XX CONGRESSO NAZIONALE DI CATALISI XX CONGRESSO NAZIONALE … · XX Congresso Nazionale di Catalisi...

BOOK OF ABSTRACTS

XX CONGRESSO NAZIONALE DI CATALISI

XX CONGRESSO NAZIONALE DELLA DIVISIONE DI CHIMICA INDUSTRIALE

2-5 SETTEMBRE 2018

Politecnico di MilanoCampus Bovisa - Edificio BL28Milano - Italy

Divisione di ChimicaIndustriale

Gruppo Interdivisionaledi Catalisi

XX Congresso Nazionale di Catalisi XX Congresso Nazionale della Divisione di Chimica Industriale

Contributi Orali Domenica 2 Settembre


The Water Gas Shift Reaction: are new findings possible for a widely investigated reaction?

G. Brenna1, R. Faure2, G. Fornasari1, D. Gary2, C. Lucarelli3, C. Molinari1, N. Schiaroli1 and A. Vaccari1

1 Dip. di Chimica Industriale “Toso Montanari”, Via Risorgimento 4, 40136 BOLOGNA (I) 2 CRCD Air Liquide, 1 Chemin de la Porte des Loges, 78354 Jouy-en-Josas (F)

3Dip. di Scienza ed Alta Tecnologia, Via Valleggio 9, 22100 COMO (I)

e-mail: [email protected]

H2 is a key raw material in chemical and petrochemical industries, with further increasing interest as promising energy vector. The water gas shift reaction (WGSr) is an industrially relevant reaction, which takes place in large scale plants and represents a key upgrading step allowing to adjust different syngas (CO + H2) compositions [1.2]. The WGSr is an exothermic reaction thermodynamically favored at low temperature, while higher reaction rates are favored at higher temperature, which is why it is currently carried out in 2 steps [1]: i) immediately after the steam reforming reactor (SRr) operating at about 350°C with Cr-rich Fe-based catalysts (HTS); ii) in the subsequent converter at about 220 °C using highly active Cu-based catalysts (LTS).

Although on account of its high industrial relevance, the WGSr has been widely investigated, in the last years new subjects arised, with an increasing interest for new formulations able to operate in one step at middle temperature (MTS) [3] or to replace the Cr-rich catalysts for HTS step. The former formulations operate at about 300°C with high activity, selectivity and stability with time-on-stream (TOS) reducing capital and operational expenditures (CAPEX and OPEX, respectively). The CO conversion may be increased expanding the Prox step, already present when the application of the H2 stream is low temperature fuel cells. In the second case, the main drawbacks of current Cr-promoted Fe-based HTS catalysts are the toxicity of Cr(VI) ions and the requirement to use high inlet steam flow to avoid the formation of metallic Fe, able to catalyze hydrocarbons formation. Thus, new formulations have to be Cr- and Fe-free and to operate with low steam/dry gas ratios, allowing to work more efficiently in the previous SRr, with catalytic performances better than those of commercial catalysts.

In this talk the R&D from the laboratory to the pilot plant of new formulations for MTS and HTS applications are presented, to evidence how also already widely investigated reactions such as the WGSr may offer interesting opportunities of new research lines and applications of both academic and industrial interest. To obtain active catalysts and avoid interferences due to structure dishomogeneity or phase segregation, hydrotalcite-type (HT) anionic clays were selected as catalyst precursors, which are characterized by homogeneous cation distribution and are simple and relatively inexpensive to prepare on laboratory or industrial scale. The catalysts were fully characterized before and after reaction and the activity determined as a function of the reaction parameters, allowing to determine best compositions for each temperature range. Tests performed in a lab-scale pilot plant for more than 450 h of time-on-stream do not evidence any significant deactivation both in MTS and HTS conditions.

References 1. M.Y. Twigg (Ed.), Catalyst Handboock, 2nd Ed,. 1989, Wolfe, London.

2. T.E. Springer, T. Rockward, T.A. Zawodzinski, S. Gottensfeld, J. Electrochem. Soc. 2001, 148, A11-A23.

3. E.M. Fuentes, F.J. Cadete Santos Aires, S. Prakash, A. da Costa Faro Jr, T. De Freitas Silva, J. Mansur Assaf, M. do Carmo Rangel, Hydr. Energy 2014, 3, 815-828.

4. S. Winter-Madsen, H. Olsson, Hydr. Eng. 2007, 7, 37-40.

PM1


Role of electronic structure theory in catalysis: concepts, examples, and

perspectives

Gianfranco Pacchioni Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca,

via R. Cozzi, 55 - I-20125 Milano, Italy e-mail: [email protected]

The role of electronic structure theory in the rationalization of catalytic processes on solid surfaces and in the design of new catalysts has grown continuously over the past 20 years. The two fundamental approaches to the solution of the Schrödinger equation, based on wave function determination (e.g. Hartree-Fock and post-Hartree-Fock) or based on electron density determination (density functional theory, DFT) have been applied to the problem, both with advantages and limitations. Particular important is the identification of proper descriptors in catalytic reactions, and the derivation of general concepts from theoretical studies. As specific example of simulations in heterogeneous catalysis we will consider the case of metal/oxide interfaces. Nanoparticles deposited on an oxide support, or nanostructured oxides grown on a metal surface may result in new efficient catalysts. We will discuss in particular the high reactivity of the oxygen atoms at the boundary region between a metal cluster and the oxide surface in CO oxidation, a prototype reaction [1-3]. Au nanoparticles on TiO2 and ZrO2 supports will be used to provide compelling evidence that the reaction occurs at specific sites of the Au/oxide interface and that even a non-reducible oxide such as ZrO2 can become reducible when interfaced with gold. Also the deposition of oxide ultrathin films on metals may result in completely different properties of deposited metal clusters, and recent examples of this effect will be discussed for ultrathin ZnO layers on Cu [4,5]. Examples of successful stories as well as cases of complete failures in predicting catalytic mechanisms from first principles will be addressed, in order to provide a coherent picture of the present status of theoretical simulations of heterogeneous catalysis. References 1. A. Ruiz Puigdollers, P. Schlexer, S. Tosoni, G. Pacchioni, “Increasing oxide reducibility: the role of metal/oxide interfaces in the formation of oxygen vacancies”, ACS Catalysis, 7, 6493 (2017). 2. A. Ruiz-Puigdollers, G. Pacchioni, “CO oxidation on Au nanoparticles supported on ZrO2: role of metal/oxide interface and oxide reducibility”, ChemCatChem, 9, 1119 (2017). 3. P. Schlexer, D. Widmann, J. Behm, G. Pacchioni “CO oxidation on a Au/TiO2 nano-particle catalyst via the Au-assisted Mars-van-Krevelen mechanism”, ACS Catalysis 8, 6513-6525 (2018). 4. S. Tosoni, C. Li, P. Schlexer, G. Pacchioni, “CO adsorption on graphite-like ZnO bilayers supported on Cu(111), Ag(111) and Au(111) surfaces”, J. of Physical Chemistry C, 121, 27453 (2017). 5. H. V. Thang, S. Tosoni, G. Pacchioni, “Evidence of charge transfer to atomic and molecular adsorbates on ZnO/X(111) (X = Cu, Ag, Au) ultrathin films. Relevance for Cu/ZnO catalysts.”, ACS Catalysis, 8, 4110-4119 (2018).

PM2


L’industria chimica italiana dalla Bovisa alla fotografia attuale

F. Trifirò Professore emerito Università Bologna

Dipartimento Chimica Industriale “Toso Montanari” Viale Risorgimento 4 40136 Bologna [email protected]

L’industria chimica italiana è nata praticamente alla Bovisa nel 1882 con la realizzazione del primo grande impianto di acido solforico e successivamente ci fù l’ insediamento di diverse industrie in gran parte di chimica specialistica e nel passato è stato il più importante polo chimico italiano, ma occorre ricordare che negli anni 70 tutti gli impianti chimici furono chiusi. I primi industriali che scelsero di localizzare i propri stabilimenti alla Bovisa furono Giuseppe Candiani, e Antonio Biffi che possono essere considerati pionieri della chimica italiana che costruirono l’impianto di acido solforico. I vantaggi della Bovisa a quei tempi come insediamento industriale era la localizzazione nella direttrice che congiungeva Milano con le aree industriali del nord e soprattutto, in seguito all’apertura del Traforo del San Gottardo nel 1882, direttamente con l’Europa centrale(1). Nel 1886 l’ing. Luigi Vogel avviò la produzione di perfosfato che insieme alla Candiani fu poi aggregata nel 1920 alla Montecatini. Accanto alla Candiani sorsero negli anni seguenti numerosi altri stabilimenti chimici che diedero vita ad un vero e proprio polo della chimica inorganica di base e successivamente anche della chimica secondaria attraverso la produzione di concimi, vernici e saponi. In particolare la Fabbrica dei saponi Calamari (poi Sirio), la Edoardo Piatti (poi Ivi - Industria Vernici Italiane), la Carlo Erba che insediò i propri stabilimenti di produzioni farmaceutiche e la Brill, azienda leader nella produzione di lucido per scarpe. La Lepetit la prima produttrice di antibiotici di sintesi creò nel 1963 un centro di ricerca e sviluppo Nei 1905 entrò in funzione alla Bovisa il più grande stabilimento d’Italia per la produzione e distribuzione del gas e la lavorazione dei sottoprodotti, Infine nel 1937, Rodolfo Squinzi fondò la M.A.P.E.I. – Materiali Autarchici Per Edilizia. Ma la chiusura della Bovisa non è stato un problema per la chimica italiana, perché si è decentrata su tutta la Lombardia . L’industria chimica italiana con circa 2.800 imprese e oltre 107 mila addetti – realizza in Italia un valore della produzione pari a circa 55 miliardi di euro (anno 2017) e si conferma il terzo produttore europeo, dopo Germania e Francia, e il nono a livello mondiale(2). L’Italia si posiziona al secondo posto in ambito europeo per numero di imprese attive nella ricerca (circa 680) con un’incidenza sull'occupazione ben più elevata della media industriale italiana (5% rispetto a 3%). L’industria chimica destina oltre la metà della produzione all'export (30 miliardi di euro nel 2017) e si è affermata quale terzo settore esportatore italiano con ritmi di crescita, dal 2010, superiori ai principali produttori europei. Le imprese straniere producono per valore 20 miliardi di euro ed è. rilevante il loro impegno nella R&S (170 milioni di euro all’anno) e nel 2014, le prime due imprese italiane per numero di brevetti depositati all’EPO sono risultate aziende chimiche a capitale estero. Il settore della chimica specialistica è il settore più importante e la Lombardia è la regione con la maggiore percentuale di aziende chimiche, possiamo dire che il polo chimico della Bovisa si è distribuito su tutta la regione.

1) aim.milano.it/tool/download.php?id=5446&idst=551

2) http://federchimica.it/dati-e-analisi/i-numeri-della-chimica

KN1


Contributi Orali Lunedì 3 Settembre


Exploitation of Lewis and Brønsted acid sites of catalytic materials based on silica and alumina

Guido Busca

Dipartimento di Ingegneria Civile, Chimica e Ambientale, Università di Genova e-mail: [email protected]

Materials based on the composition of silica and alumina display tunable acidobasic properties justifying their wide use as catalysts as well as catalyst supports [1]. Transitional aluminas, such as -Al2O3, -Al2O3, -Al2O3 and -Al2O3, are typical ionic oxides whose surface chemistry is characterized by strong Lewis acid sites and by strong acido-basic couples. For these reasons they are used as industrial acid catalysts (e.g. for alcohol dehydrations to ethers and olefins, and for the Claus process) but also as highly dispersing supports for a number of metallic, oxide, sulphide and halide catalysts [2]. The nature and location of the active sites on transitional aluminas is still in part under discussion. New experimental data suggest that they are mainly due to 3- and 4-coordinated Al ions coupled to highly exposed oxide anions placed on edges between non-basal planes of the spinel-like crystal structure of these materials, and that they may mask themselves upon surface reconstruction occurring in vacuum atmospheres used for some spectroscopic investigations. Alumina surfaces also present surface hydroxy-groups characterized by weak but non negligible Brønsted acidity. Doping, e.g. with lanthanum [3,4], allows to tune strength and density of sites. Amorphous silica-aluminas (ASAs) are a family of materials also largely used as catalysts and catalyst supports. The silica-rich materials are actually completely amorphous. These materials are characterized by the presence of strong Lewis acid sites similar in quality to but less in amount than the strongest Lewis sites of aluminas (3-coordinated Al ions). ASAs however do not present the basic counterpart of these sites, being their surface oxygen atoms bonded to two silicon atoms (siloxane bridges). These materials display also a small density of moderately strong Brønsted acid sites, whose origin is still under discussion. Experimental data suggest that these sites are terminal silanols prerturbed by mobile Al cations in a "stuffed amorphous silica" structure [5]. Alumina-rich silica-aluminas and silicated aluminas are also relevant materials in catalysis. Silicated aluminas contain surface terminal hydrogensilicate species interacting on the strongest Al-O acidobasic couples, that reduce dispersion of the supported species (e.g. nickel particles of Ni/Al2O3 hydrogenation catalysts [6], molybdate species for MoO3/Al2O3 oxidation catalysts as well as hydrotreating sulphide catalysts precursors [7]) thus improving properties of supported catalysts. Alumina-rich silica-aluminas are essentially biphasic materials, presenting together an amorphous silica-rich phase typical of ASAs and an alumina-rich phase typical of silicated aluminas. The strong Brønsted acidity of protonic zeolites is associated to a different generation mechanism where the microporous covalent silica-rich framework stabilizes strongly acidic bridging groups [8]. Reactants behaving as n-bases (i.e. using non-bonding electron pairs) can be activated by both Lewis and Brønsted sites, depending on their relative strength, while - and -bases (i.e. those molecules having avilable and electron pairs) are activated by protonation on Brønsted acid sites. Also coke deactivating catalysts is different when generated by Lewis and Brønsted sites. References

1. Busca, G., Heterogeneous Catalytic Materials, Elsevier, 2014, pp. 103-196 2. Busca, G., Advan. Catal., 2014, 57, 319-404 3. Garbarino,G. et al., Appl. Catal. B, Envir, 2018, 236, 490-500 4. Garbarino,G., et al., Appl. Catal. B, Envir, 2017, 200, 458-468 5. Sanchez Escribano, V., et al., Topics in Catal., 2017, 60, 1554-1564 6. Garbarino, G., et al. Appl. Catal. A Gen., 2015, 502, 86-97. 7. Villarreal A., et al., submitted paper 8. Busca G., Microp. Mesop. Mater. 2017, 254, 3-16.

Acknowledgements: The collaboration of Elisabetta Finocchio, Gabriella Garbarino, Thanh Khoa Phung and Vicente Sanchez Escribano is gratefully acknowledged.

KN2


Hydrogenation of 5-Hydroxymethylfurfural to Diols: Comparison of Batch and Flow Reactors

S. Fulignatia, C. Antonettia, D. Licursia, M. Pieraccionia, H. J. Heeresb, A. M. Raspolli Gallettia

a Chemistry and Industrial Chemistry Department, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy. b Chemical Engineering Department, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.


Nowadays, the dwindling supplies of worldwide fossil resources and the growing of environmental pollution make the production of chemicals and fuels from renewable resources a key topic of the industrial chemistry 1. Under this perspective, 5-hydroxymethylfurfural (HMF) is considered as one of the top 12 bio-based compounds: it can be obtained from the dehydration of biomass-derived sugars 2,3 and its reactive structure makes it a very important platform-chemical, being precursor of fuels, monomers and other valuable products 4. In this work, the selective hydrogenation of HMF to two diols, 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-(hydroxymethyl)tetrahydrofuran (BHMTHF), both promising monomers for the synthesis of renewable polymers 5, was investigated and optimized both in batch and flow reactors.

In the batch reactor, the hydrogenation was carried out starting from HMF aqueous solution and several supported metal catalysts were tested. Ru/C resulted to be the most promising one, allowing us to obtain BHMF yield of 93 mol% and BHMTHF yield of 95 mol%, under the respectively optimized reaction conditions. The spent catalyst was recovered at the end of the reaction and its stability was evaluated trough BET, TGA, ICP and TEM techniques, which showed the presence of humins on catalyst surface, negligible leaching of ruthenium and also slight sintering of the catalyst. On the other hand, in the flow reactor HMF hydrogenation was carried out adopting comparable conditions. In this case, Ru/C was stable up to 14 hours of time-on-stream, due to the deposition of humins on its surface, as proved by BET analysis of the spent catalyst. However, Ru/C resulted especially promising also in the flow reactor. In fact, it allowed us to obtain BHMF and BHMTHF with yields of 88 mol% and 93 mol%, respectively, working under the same reaction conditions (100 °C and 50 bar) and easily changing the residence time. Moreover, the presence of mass transfer limitation phenomenon was estimated through both mathematical (Weisz-Prater criterion) and empirical approaches, proving the presence of diffusion intra-particle limitation of HMF, which can contributes to the limitation of the kinetic. Finally, the spent catalyst was analysed through ICP and TEM techniques, which underlined its high stability, demonstrating that the catalyst deactivation was connected only to the humins deposition. References

1. Yu, I. K. M.; Tsang, D. C. W. Biores. Technol. 2017, 238, 716-732. 2. Antonetti, C.; Melloni, M.; Licursi, D.; Fulignati, S.; Ribechini, E.; Rivas, S.; Parajó, J. C.; Cavani, F.; Raspolli

Galletti, A. M. Appl. Catal. B: Env. 2017, 206, 364-377. 3. Antonetti, C.; Raspolli Galletti, A. M.; Fulignati, S.; Licursi, D. Catal. Commun. 2017, 97, 146-150. 4. Hu, L.; Lin, L.; Wu, Z., Zhou, S., Liu, S. Renew. Sust. Ener. Rev. 2017, 74, 230-257. 5. Tang, X.; Wei, J.; Ding, N.; Sun, Y.; Zeng, X.; Hu, H.; Liu, S.; Lei, T.; Lin, L. Renew. Sust. Ener. Rev. 2017, 77,

287-296.

O01AM


Selective Recovery of carbon supported catalyst

A. Bellè, A. Perosa, M. Selva Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Via Torino 155, Venezia-Mestre, 30175 – Italy.

Email: [email protected]

Multiphase systems (MPs) composed of multiple immiscible phases have been extensively used to run organic reactions in the presence of heterogeneous metal-based catalysts.1,2 Although this configuration allows an efficient recovery of catalysts and products, it may often limit the activity of catalysts, thereby requiring harsher conditions to push reactions to completion. With the aim of investigating solutions to this issue, we were able to develop a simple and effective procedure for the selective separation of C-supported metal catalysts from an aqueous to an organic (hydrocarbon-based) phase. As an example, starting from a bi-phasic water-isooctane system, a model reaction such as the hydrogenation dehydration of levulinic acid (LA) has been explored in the presence of a Ru/C catalyst. At 65 °C and 35 bar (H2), not only the reaction occurred in the aqueous phase by producing the expected product, γ-valerolactone, with almost quantitative selectivity and yields, but also the metal catalyst could be selectively transferred in the isooctane phase. The protocol has been extended to more complex reaction such as the reduction of LA in presence of formic acid and the reductive amination and cyclization of LA to pyrrolidones (Figure 1 left). In all cases, complete conversions and yields up to 85-95% were reached, while the catalyst was efficiently recycled without any loss of activity (Figure 1 right). A plausible explanation for the observed behaviour considers the effect of the pH of the reactant solution. Also, the hydrogenolysis of glycerol has been studied, during which the segregation of Ru/C catalyst in the organic was achieved by compressed (supercritical) CO2 able to confer the required acidity to the MP system.3 Yet, the selectivity of the reaction was (and still is) an issue due to the occurrence of competitive side-reactions of C-C bond cleavage.

Figure 1: scheme of the reactions studied (left), picture of the recycling process (top right) and recycling data for the Levulinic acid

hydrogenation (bottom right).

References: 1. A., Perosa, Chem. Soc. Rev., 2007, 36, 532-550. 2. M., Selva, ACS Sustainable Chem. Eng., 2013, 1, 180-189 3. K. L., Toews, Anal. Chem., 1995, 67, 40-40.

O02AM


New synthetic strategies for an efficient production of organic carbonates and related innovative applications

T. Tabanellia, S. Cailottob, E. Montia, J. Strachanc, A. F. Mastersc, T. Maschmeyerc, A.

Perosab, M. Selvab and F. Cavania aDipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna, Viale Risorgimento 4, 40136 Bologna,

Italy. bDipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari, Via Torino 155, 30172 Venezia Mestre,

Italy cLaboratory of Advanced Catalysis for Sustainability, School of Chemistry-F11, The University of Sydney, NSW 2006,

Australia e-mail: [email protected]

Organic carbonates (OCs) are an important class of molecules with a wide range of applications, such as aprotic polar solvents, monomers, surfactants, plasticizers and electrolytes to name a few. OCs peculiarities are the non-toxicity and a good biodegradability.1 Because of these reasons their importance as chemical intermediates is continuously increasing. Nowadays, cyclic carbonates (e.g ethylene carbonate, EC) are synthesized from the corresponding epoxides and CO2 by a cycloaddition reaction, on the other hand, the direct condensation of CO2 and alcohols to yield linear OCs suffers from strictly thermodynamic limitations and needs of high energy input that make difficult the application on an industrial scale.2 Therefore, the simplest linear carbonate, dimethyl carbonate (DMC) is produced by the transesterification of EC and methanol, also referred to as carbonate-interchange reaction (CIR). This reaction is a promising synthetic pathway also for the production of higher OCs, carried out by reacting a commercial carbonate (mainly DMC or EC) with alcohols and diols. Unfortunately, these are equilibrium-limited reactions, especially for the synthesis of aromatic carbonates, such as diphenyl carbonate (DPC). Therefore, special reaction systems able to promote the continuous removal of at least one product are required, in order to shift the reaction equilibrium.3 In this context, we have investigated the synthesis of an innovative cyclic aromatic carbonate, the catechol carbonate (CC), starting from catechol and DMC (that act also as the reaction solvent, so limiting the formation of waste) in the presence of a basic catalyst (either NaOCH3 or ionic liquid) and working with a reactive distillation system (RDS) able to promote the removal of the co-produced methanol. Moreover, we have implemented our RDS with the selective adsorption of methanol inside molecular sieves, an option that finally allowed us to remarkably improve yield and selectivity to CC (yield≥95% after 24h), with a negligible loss of DMC that could be recycled.4 Afterwards, CC was investigated as an alternative, more efficient carbonate source for the selective synthesis of a wide plethora of both dialkyl and alkylene carbonates in the presence of a basic catalyst. Indeed the results obtained in very mild reaction conditions (40-80°C, ambient pressure) and low reaction time (30 to 60 minutes) proved an unprecedented outstanding potential of CC, that promoted the quantitative formation of aliphatic symmetric carbonates (ROCO2R) and glycerol carbonate (GlyC), these products being elusive in the CIR of both EC and DMC.5 Finally, a completely innovative and greener synthetic pathway toward 2-hydroxymethyl-1,4-benzodioxane (HMB), a key intermediate for the pharma, has been developed and patented, taking advantage of the peculiar reactivity of GlyC as alkylating agent for catechol (HMB yield up to 88%).6 References

1. J.H. Clements. Industrial & Engineering Chemistry Research, 2003, 42(4), 663-674. 2. E. A. Quadrelli et al. ChemSusChem, 2011, 4 (9), 1194-1215. 3. H-J. Buysch. Carbonic Esters. Ullmann’s Encyclopedia of Industrial Chemistry, 2012. 4. T. Tabanelli et al. Catal. Sci.Technol. 2018, 8, 1971-1980. 5. T. Tabanelli et al. Green Chem. 2017, 19, 1519-1528. 6. T. Tabanelli et al. PCT/EP2018/000113 (2018).

O03AM


Catalytic upgrading of lactose: a rest raw material from the dairy industry

F. Zaccheria, V. Pappalardo, N. Scotti, R. Psaro, N. Ravasio

aISTM CNR, Via Golgi 19, 20133 Milano, Italy e-mail: [email protected]

The valorisation of wastes originating from the agro-food industry is a highly strategic way to face the circular economy challenge.1 Among these, milk whey from cheese production is a significant one and the high quantity of lactose derived after protein extraction (e.g. 80 000 tons per year in the plant of Arla in Denmark) pushes to its upgrading into more valuable derivatives, not only as a food ingredient, but also as a raw material for the bio-based industry. The one-pot transformation of lactose into sorbitol and dulcitol has been tested by using two low loading copper catalysts prepared by the chemisorption-hydrolysis technique over different kinds of silica (See figure and table). Silica supported copper catalysts gave effectively good results in the one-pot transformation of lactose into a high yield mixture (75–86%) of sorbitol and dulcitol.2 Both conversion and selectivity to reduced alcohols were found to increase with temperature up to 180 °C and the experiments carried out at different temperatures allowed us to shed some light on the contribution of the two pathways shown in Scheme. The process selectivity can be switched to direct hydrogenation of lactose to lactitol only by changing the solvent. The effect of the textural properties of the different silica has been also studied. References

1. A. S. Matharu, E. M. de Melo, J. A. Houghton, Bioresour. Technol., 2016, 215, 123 2. F. Zaccheria, M. Mariani, N. Scotti, R. Psaro, N. Ravasio, Green Chem., 2017, 19, 1904

Acknowledgements: COST Action TD1203 EUBis “Food waste valorization for sustainable chemicals, materials & fuels” is acknowledged for support

Cat T (°C) Conv % % 4 %3 % 5+6 Cu/SiO2 A 180 100 5 8 80 Cu/SiO2 B 150 72 16 17 22 Cu/SiO2 B 160 96 18 17 57 Cu/SiO2 B 180 100 5 8 75

O04AM


Vanadium(V) Aminotriphenolate Complexes as Catalysts for Lignin Oxidative Depolymerization

D. Carraro, E. Amadio, W. Denis, C. Zonta and G. Licini

Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padova, Italy. e-mail: [email protected]

In recent years, valorization of non-food renewable carbon feedstocks has been gaining much more attention. Among these sources, lignin is one of the cheapest and most Earth abundant biomasses. With its unique structure, lignin can be therefore regarded as the major aromatic resource of the bio-based economy and, therefore, a wide variety of aromatic compounds may result from its efficient valorization1. However, despite its potential as a feedstock for the production of fuels and chemicals, lignin remains the most poorly utilized of lignocellulosic biopolymers. This is mainly due to its complex nature, inert resistance to chemical reactivity and the lack of suitable conversion technologies. Therefore, selective lignin depolymerization to value-added products remains a challenge2. In particular, the development of robust catalysts that selectively target C-C bonds cleavage in lignin structure can be a key in overcoming the problem3. In recent years, it emerged that VV aminotriphenolate complexes (VO(R,R’))4 are good candidates to achieve such ambitious goals in a very active and selective manner under rather mild reaction conditions (Figure 1).

Figure 1. Selectivity in the aerobic oxidative bond cleavage of lignin model (1) by VO(R,R’).

In this communication, we therefore describe the catalytic activity of (VO(R,R’)) in oxidative cleavage of lignin models containing β-O-4 bonds (1). In particular, we will report results about the selectivity with respect to the kind of cleavage that such systems can undergo (specifically Cα-Cβ vs Cβ-O vs Cα-H).

References 1 Flores, F. G. C.; Dobado, J. A.; ChemSusChem 2010, 3, 1227. 2 Zakzeski, J.; Bruijnincx, P.; Jongerius, A.L.; Weckhuysen, B. M. Chem. Rev. 2010, 110, 3552. 3 Amadio, E.; Di Lorenzo, R.; Zonta, C.; Licini, G. Coord. Chem. Rev. 2015, 301-302, 147. Hanson, K. S.; Baker, R. T. Acc. Chem. Res. 2015, 48, 2037 and references therein. 4 M. Mba, M. Pontini, S. Lovat, C. Zonta, G. Bernardinelli, E.P. Kündig, G. Licini, G. Inorg. Chem. 2008, 47, 8616. Acknowledgements: This work was funded by University of Padova.

O05AM


Towards the continuous production of supported metal nanoparticles in

continuous for applications in catalysis

S. Cattaneoa,b, N. Dimitratosa, S. J. Freakley,a M. Sankar,a L. Pratib, G. J. Hutchingsa aCardiff Catalysis Institute, Cardiff University, Cardiff, CF10 3AT, United Kingdom

bDipartimento di Chimica, Università degli Studi di Milanoy, Via C. Golgi 19, 20133, Milano, Italy *Corresponding author: [email protected]

Metal supported nanoparticles are commonly produced chemically by batch methods, such as deposition-precipitation, impregnation or sol-immobilisation1. All these techniques, however, suffer from some common problems like inhomogeneous mixing of the reactants, inhomogeneous heat transfer, and difficult scale-up, and these problems may lead to differences in terms of nanoparticles dimension from one batch to another or broad particle size distributions2. To overcome these problems, microreactors have been proposed as alternative technique for the production of metal colloids in continuous systems; although they can provide better mixing and heat transfer, they are often difficult to fabricate, expensive and hard to scale-up3. We report a semi-continuous millifluidic apparatus (Figure 1a) that combines the advantages of both batch and microflow techniques, in order to produce stable monometallic nanoparticles with a very small dimension (2-3 nm) and narrow size distribution. The catalysts as prepared were thoroughly analysed with UV-Vis, DLS and HRTEM, and finally tested for nitrophenol reduction, a model reaction very sensitive to changes in nanoparticles dimension and thus suited to highlight and emphasise structure-activity relationships4. By using Au as a test metal we optimised several operational parameters, such as flow rate, reactor length, reactor geometry and concentration of PVA, NaBH4, and Au. The reactor geometry, in particular, was studied by designing and printing custom-made connections and reactors with different shapes; a stereolithography 3D printer was employed for this purpose. Finally, we integrated a stream of support suspended in water to the as prepared Au colloid (Figure 1, red box) in order to produce the whole catalyst in a continuous process. Smaller nanoparticles were produced compared with both the semi-continuous and the batch-benchmark catalysts, and this is also confirmed by the catalytic tests (Figure 1b). It is obvious that the immediate supporting of the Au colloid onto the TiO2 is beneficial, probably because of two effects, the absence of stirring that makes more difficult any agglomeration phenomena and the immediate removal of the NaBH4 remained in solution that can no longer interact with the PVA.

0 2 4 6 8 10 12 14 16

0

5

10

15

20

25

30

35

40

k (1

03 s

-1)

Metal surface area (m2/mg)

Batch

Continuous

Figure 1: (a) Scheme of the continuous setup for the production of supported metal nanoparticles and (b) correlation

between nanoparticle dimension and catalytic activity for the nitrophenol reduction reaction. References (10 pt)

1. M. Sankar et al., ACS Nano 2012, 6, 6600-6613.

2. J. Wagner et al., Nano Lett. 2005, 5, 685-691.

3. S. E. Lohse et al., ACS Nano 2013, 7, 4135-4150.

4. C. Linn et al., Molecules 2013, 18, 12609-12620.

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Effect of the preparation method of Pd/TiO2 catalysts on the activity and

selectivity in the hydrogenation of citronellal

S.Alijani, A.Villa, F.Tessore

Department of Chemistry, University of Milan, via Golgi 19, 20133 Milano (Italy) [email protected]

Citronellal represents an organic substrate of significant interest for the preparation of several high-demand chemicals [1]. Palladium catalysts rank among hydrogenation catalysts most frequently in use, predominantly due to some of their specific propertied such as high activity in the hydrogenation of many types of bonds, ability to absorb large volumetric quantities of hydrogen at room temperature and atmospheric pressure, and high stability [2]. The chemoselective

hydrogenation of citronellal mainly produces the tertiary alcohol (3,7-Dimethyl-octanol), the unsaturated alcohol (citronellol), the unsaturated cyclic alcohols (isopulegol, an important intermediate for producing menthol), and a minor amount of medium-chain aldehyde (3,7-Dimethyl-octanal) (scheme.1) [3]. In the present study, the hydrogenation of citronellal was carried out with Palladium/TiO2 catalyst, synthesized by sol immobilization or wet impregnation, using different solvents (water, ethanol and methanol). The reactions have been performed in a batch reactor under mild conditions (30 °C and 3 bar hydrogen) and the products of reaction have been analyzed by a combination of GC and GC-MS. The results indicated that the Pd/TiO2 catalysts prepared by wet impregnation and sol immobilization methods, with water as the solvent were the most active and selective catalysts

reaching a selectivity to 3,7-Dimethyl-octanol of (90-92%) after six hours of reaction. Finally, the synthesized catalysts were characterized by TEM and XPS. The main aim of this research is to evaluate the effect of the protective agent and the solvent utilized in the catalyst preparation on the activity and selectivity towards the desired products. References.

1. Dhiaul.E, Indo. J. Chem., 2010, 10 (2), 208 – 213. 2. Nishimura.S, John Wiley & Sons, Inc, Canada, 2001. 3. Weiyong.Y, Issue 1,44, 2000, 21-29.

Scheme 1. Proposed pathway for citronellal hydrogenation

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H2-induced reconstruction of Pt nanoparticles in Pt/Al2O3 monitored by coupled DRIFT/XAS approach

M. Carossoa, E. Votteroa, A. Lazzarinib, S. Morandia, M. Manzolic, K. A. Lomachenkod,

A. Piovanoe, R. Pellegrinif, C. Lambertia, E. Groppoa aDepartment of Chemistry, NIS and INSTM, University of Turin, Via P. Giuria 7, Turin, Italy bCentre for Materials Science and Nanotechnology, Dep. of Chemistry, University of Oslo, Norway cDepartment of Drug Science and Technology, NIS, University of Turin, Via P. Giuria 9, Turin, Italy dEuropean Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France eInstitut Laue-Langevin (ILL), 71 Avenue des Martyrs, 38000 Grenoble, France fChimet S.p.A. – Catalyst Division, Via di Pescaiola 74, Viciomaggio Arezzo, Italy


Determining the electronic and morphological features of metal nanoparticles as a function of the employed support, the type of adsorbate and the reaction temperature is currently one of the main challenge in the field of metal-supported catalysts. In this work, the behavior of a 5wt% Pt/Al2O3 catalyst is investigated under different conditions by means of FT-IR spectroscopy at first, and successively by a synchronous DRIFT/XAS approach. Pt-hydrides (PtHx) are formed in a H2/N2 flow at 120 °C and detected by FT-IR spectroscopy. Surprisingly, when H2 is removed by the reaction feed, the IR bands associated to linear PtHx increase in intensity with a slow kinetic, rapidly disappearing only after the achievement of a maximum (Figure 1a). With the aim to correlate the FT-IR results with the structural properties of the Pt nanoparticles, we have successively coupled DRIFT with XAS spectroscopy at the Pt L3-edge in both XANES and EXAFS regions (Figure 1b). In this way, we monitored the electronic and morphological changes occurring at the metal phase during the dehydrogenation of Pt/Al2O3. Our data are in very well agreement with a series of theoretical models (Figure c) proposed in the literature, that predict important morphological changes occurring at the Pt nanoparticles in the presence and in the absence of H2 [1, 2]. It is worth noticing that, to the best of our knowledge, this is the first attempt to couple DRIFT and XAS spectroscopies in the study of H2-treated Pt-based heterogeneous catalysts.

Figure 1. Part a): 2D map showing the evolution of the FT-IR spectra as a function of time for the Pt/Al2O3 catalyst during dehydrogenation in N2 flow (20 mL/min) at 120 °C. The previous reduction step was accomplished in the presence of 10% H2 in N2. Three FT-IR spectra selected at specific times (1, 2 and 3 in the 2D map) are also shown. Part b): Pt L3-edge XANES and EXAFS spectra at 4 selected times in the DRIFT/XAS experiment. Part c): H2-induced reconstruction of Pt nanoparticles as a function of the H coverage, as predicted in Ref. [1].

References

1. Mager-Maury C., Bonnard G., Chizallet C., Sautet P., Raybaud P.; Chem. Cat. Chem. 2011; 3; 200-207. 2. Wang L., Johnson D. D.; J. Am. Chem. Soc. 2007; 129; 3658-3664.

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Simultaneous Production of Sulfur and H2 by Catalytic Oxidative Decomposition of H2S

D. Barbaa, V. Vaianoa, V. Palmaa, M. Colozzib, E. Palob

aUniversity of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy bKT Kinetics Technology, Viale Castello Della Magliana 75, 00148 Rome, Italy


The direct recovery of H2 and sulfur from H2S has attracted some research interests and many approaches have been published1. Today, H2S is converted by the Claus process to Sulphur and H2O, but it isn’t profitable because the price of sulphur is depressed and the hydrogen is lost as low grade steam. In this regard, an attractive alternative could be that to produce Sulphur and H2 from H2S, but this reaction is very endothermic and it isn’t thermodynamically favored, if not for extremely high temperatures, requiring subsequent separation stages, large amounts of energy, high fixed and operating costs. A possible solution is to couple the decomposition reaction with an exothermic reaction, making the system autothermal by adding an appropriate amount of oxygen, in order to use the heat produced by the oxidation of a rate of H2S, to obviate to the endothermicity of the decomposition reaction, obtaining simultaneously sulphur, H2O and H2

2. In our previous works, we have studied the reaction of H2S thermal decomposition in presence of oxygen in homogeneous phase3 and with alumina-based catalyst4. To our knowledge no papers regarding the use of a catalyst different than alumina in the oxidative H2S decomposition for the simultaneous production of H2 and sulfur have been published. For this reason, in this work, the oxidative decomposition of H2S has been assessed for the first time using a metal sulfide-based catalyst supported on Al2O3. The influence of the main operating conditions on H2S conversion, H2 yield and SO2 selectivity has been investigated in order to improve the process selectivity towards H2 and sulphur with SO2 zero emission . The increase of the H2S inlet concentration from 10 up to 40 vol% has determined a decrease of H2 yield and a slight increase of the SO2 selectivity; the same behaviour was observed by increasing the feeding molar ratio O2/H2S, evidencing that the SO2 formation is strictly related to the presence of the oxygen in the reaction system. The tests at different reaction temperatures (700-1100 °C) evidenced that, with respect to the Al2O3 support and to the homogeneous reaction, the catalyst was able to minimize the SO2 selectivity allowing to obtain H2S conversion and H2 yield values very close to those ones expected by the thermodynamic equilibrium. Based on the obtained results, the optimal operating conditions suitable to obtain a high H2S conversion (59 %), a good H2 yield (20 %) with a very low SO2 selectivity (< 0.05 %) were identified (T=1100 °C, O2/H2S = 0.2, H2S =10 vol%). In summary, the molybdenum-based catalyst has favoured both the H2S thermal decomposition reaction to produce H2 and sulfur and the H2S partial oxidation reaction to sulfur and water, promoting also the consumption of SO2 by the Claus reaction. References

1. Zaman, J., Chakma, A., Fuel. Proc. Tech. 1995, 41, 159–198. 2. Palo, E., Barbato, L., Colozzi, M., Angelini, F., Palma, V., Vaiano, V. 2014, Patent No WO2014073966 A1. 3. Palma, V., Vaiano, V., Barba, D., Colozzi, M., Palo, E., Barbato L., Cortese, S., Intern. J. Hydr. Energy. 2015, 40,

106-113. 4. Palma, V., Vaiano, V., Barba, D., Colozzi, M., Palo, E., Barbato L., Cortese, S., Ind. Eng. Chem. Res. 2017, 56,

9072-9078.

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…and sustainable processes for the synthesis of fine and specialty chemicals

O. Piccolo

Studio di Consulenza scientifica, Sirtori, Italy,


Here will be presented some of the more significant steps of my own multi-year journey, but

obviously always working together with many valuable colleagues and collaborators in industries

and universities, to explore, develop and realize «wise» paths (Figure) in the synthesis of various

fine or specialty chemicals and of suitable and smart work tools , with data often unpublished or

disclosed only in patents or conferences.

My acknowledgements to prof. Pino, a true mentor, who opened me to the world of catalysis and gave me an important teaching on the way to work, with gratitude and memory.

PM3


Continuous Flow as enabling tool for the prompt scale-up of Gas-Liquid Catellani type reactions

A. Casnatia,b, H. P. L. Gemoetsa, E. Mottib, N. Della Ca’b, T. Noëla

aDepartment of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands

b Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy e-mail: [email protected]

Continuous processing is the most promising field in the perspective of pursuit a green chemistry and engineering for a sustainable business and environment. In 2005 the American Chemical Society (ACS), Green Chemistry Institute (GCI) and several global pharmaceutical corporations founded the ACS GCI Pharmaceutical Roundtable[1]. Their goal is to implement green chemistry and engineering into drug discovery, development and production. In 2007 the Roundtable provided a list of promising research areas that can fulfill this noble aim. Continuous processing was at the top of this rank. In this light, we reasoned that current relevant batch methodologies necessitate substantial alterations in order to allow a smooth transition towards continuous manufacturing [2]. The Pd/norbornene-catalyzed Catellani reaction represents a unique example of a Pd0/II/IV catalytic cycle, combining the effectiveness of cross-coupling with the neatness of C−H functionalization [3]. Historically, Catellani reactions have been limited to liquid or solid reagents. This can be ascribed to the fact that the use of gaseous olefins has long been avoided due to safety concerns and process constraints. Furthermore, the use of gaseous olefins would expand the scope of Catellani-like reactions, providing direct access to a series of relevant ortho-disubstituted styrenes and vinyl arenes in an atom-efficient fashion.

Our first issue was to transform the reaction procedures into homogeneous conditions for flow. After a carful survey of bases, tetrabutylammonium acetate (TBAA) proved its value by granting full conversion in 2 hours, while being completely miscible in DMF. Then a new and efficient flow methodology was developed. To test the robustness of the novel approach, different molecules were synthetized employing liquid-liquid conditions. Moreover we devoted specific attention to employ gaseous reagents, which can highly benefit from continuous-flow conditions. Ethylene, propylene and 3,3,3-trifluoro-1-propene were engaged as starting materials, allowing the possibility to insert these moieties in the targeting molecules. We tested the scalability of this new procedure and to our delight the productivity of the process was 2.8 g/d, an impressive result considering the complexity of these ortho-disubstitued styrenes. References [1] C. Jimenez-Gonzalez, Org. Process Res. Dev., 15, 2011, 900. [2] H. P. L. Gemoets, Y. Su, M. Shang, V. Hessel, R. Luque, T. Noel, Chem. Soc. Rev., 45, 2016, 83 [3] a) N. Della Ca’, M. Fontana, E. Motti, M. Catellani, Acc. Chem. Res., 49, 2016, 1389. b) E. Motti, G. Ippomei, S. Deledda, M. Catellani, Synthesis, 17, 2003, 2671 c) F. Faccini, E. Motti, M. Catellani, J. Am. Chem. Soc., 126, 2004,78

O10AM


Synthesis Effect On Structural Properties and Catalytic Performances of Ni/La2O3 Catalysts for Methane Dry Reforming

F. Puleoa, G. Pantaleoa, M.V. Grabchenkob, O. Vodyankinab L.F. Liottaa a Istituto per lo Studio dei Materiali Nanostrutturati, Palermo, Italia.

bTomsk State University, Tomsk, Russia. e-mail: [email protected]

[email protected] [email protected]

Abstract

Dry reforming of methane (DRM) is a convenient and feasible process to produce synthesis gas according to the equation: CH4 + CO2 ↔ 2CO + 2H2 [1]. The reaction is highly endothermic (ΔH°25°C = 247 kJ/mol) and normally requires temperatures above 650°C in order to reach desirable conversion levels. The composition of the produced syngas approaches a ratio H2/CO near 1 when a high selectivity towards CO2 reforming of methane is achieved. For energy saving purposes is suitable the development of new efficient catalysts active below 700 °C and highly selective to syngas production. Ni-based catalysts have been studied extensively for such purpose, being quite active and cheaper than noble metals [2]. However, the main drawback of monometallic Ni catalysts is the deactivation at high temperature due to sintering of nickel particles, nickel oxidation and coke deposition that cause catalyst poisoning [3-4]. Until now, many studies have demonstrated that metal oxides such as CeO2, MgO, ZrO2 have positive effects on catalytic activity, stability and carbon suppression of nickel catalysts for DRM [5-6]. In the present work the structural properties, the related catalytic activity and the long-run stability of Ni-La2O3 catalysts have been evaluated in DRM reaction. The aim was to investigate the effect of ammonia addition during the synthesis of La2O3 oxide carried out by sol-gel method in presence of citric acid. Ni(10%wt) was deposited by wetness impregnation over two La2O3 oxides prepared with and without adding NH3 solution during the synthesis, the corresponding catalysts were labelled as Ni-La CA and Ni-La CA-NH3, respectively. XRD patterns of the supports calcined at 800 °C showed that ammonia addition favors the formation of La2O3 phase with respect to La(OH)3. La2O3 was the only lanthanum phase detected in the XRD pattern of Ni-La CA-NH3, after calcination at 600 °C and reduction treatment at 700 °C, moreover, weak features attributed to dispersed metallic Ni particles were found. While, in the case of Ni-La CA, both phases, La2O3 and La(OH)3 were present along with well visible peaks of metallic Ni suggesting the presence of big clusters. DRM gradient catalytic test, performed between 400°C and 800°C, revealed higher catalytic activity of Ni-La CA, nevertheless long run test showed a better stability of Ni-La CA-NH3 catalyst. The spent catalysts were characterized by XRD and TGA analyses. In both samples La2O2CO3 phase was formed together with C graphite peak of higher intensity in the case of Ni-La CA in agreement with greater weight loss revealed by TGA and stronger deactivation during long run with respect to Ni-La CA-NH3. References

1. Lavoie, J.M.; Front Chem. 2014, 11, 2-81. (review) 2. Zhu, X.; Huo, P.; Zhang, Y.P.; Cheng, D.G.; Liu, C.J.; Appl. Catal. B 2008, 81, 132-140. 3. Jia, Z.; Kou, K.; Qin, M.; Wu, H.; Puleo, F.; Liotta, L.F.; Catalysts 2017, 7, 256-276. 4. Horváth A. Guczi L., Kocsonya A., Sáfrán G., La Parola V., Liotta L.F., Pantaleo G., Venezia, A.M.;

Applied Catalysis A: General 2013, 468 250– 259. 5. Mesrar, F.; Kacimi, M.; Liotta, L.F.; Puleo, F.; Ziyad, M.; Int J Hydrogen Energy 2017, 42, 19458-19466. 6. Fan, M.S.; Abdullah, A.Z.; Bhatia, S.; ChemSusChem 2011, 4, 1643-1653.

Acknowledgements: This work was supported by the Russian Presidential Scholarship assigned to M.V. Grabchenko for a stage at ISMN-CNR in Palermo, Italy.

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Innovative synthesis of nanostructured composite materials by a spray-

freeze drying process: efficient catalyst and photocatalyst preparation.

S. Albonetti a,b, M. Blosib, S. Ortellib, A. L. Costab, R. Bacilea, S. Andreolia, G. Fornasaria.

a. Dipartimento di Chimica Industriale “Toso Montanari”, University of Bologna, viale del Risorgimento 4, 40136

Bologna, Italy.

b. ISTEC-CNR, Institute of Science and Technology for Ceramics, National Research Council, Via Granarolo 64,

48018, Faenza, Italy

e-mail: [email protected];

1. Introduction Spray-Freeze-drying (SFD) is a drying method often encountered in pharmaceutical industry as well as in the processing of food. With this procedure, thermo-labile compounds can be dried at low temperatures to produce spherical porous particles and forming high-surface area systems. Indeed, using this method, a solvent can be removed without exposing the systems to tensile forces of a receding meniscus. Therefore, it is a suitable drying technique to develop porosity in inorganic and polymeric materials. For catalyst preparation, freeze-drying has been suggested to reduce precursor solution mobility during drying and therefore control the location of deposition of the precursor phase [1]. Moreover, the technique can be utilized to the homogeneous embedding of the active phases into the support, minimizing the possibility of phase separation on a molecular scale, as also demonstrated for drugs. Nevertheless, few applications have been reported in the catalytic field until now.

In this work, SFD was successfully applied for the preparation of nanostructured mixed oxides (TiO2/SiO2, Pt containing systems) and polymer/oxide composites (perfluorosulfonic superacid resin- Aquivion® PFSA with SiO2) with very high surface area and homogeneous dispersion of different components. The prepared materials were tested in various reaction such as: 1) the gas-phase dehydration of ethanol to ethylene (Aquivion® /SiO2 systems); 2) the oxidation of hydroxymethylfurfural (Pt containing catalysts) [2]; 3) the photodegradation of rhodamine B, used as a stain model (TiO2/SiO2 materials) [3]. The mixed-oxides and polymer/oxide composites were produced at different compositions using a colloidal heterocoagulation method - expected to give rise to “matrix encapsulation” - associated with the spray-freeze drying. Sols containing the different oxides, latex or metal precursors were characterized by ζ-potential analyses and Dynamic Light Scattering (DLS) measurements to evidence the effect of particles charge and dimension on the material synthesis. In the process of SFD, the evaporation induced condensation of the sols, containing the different nano-oxides or polymeric latex, intimately mixed, occurs during a very short time, forming a stable network. As-synthesized and calcined catalysts were lightweight flowable powders with low bulk density as well as very high specific surface area, also in the case of perfluorosulfonic superacid resin utilization. Active species were demonstrated to be incorporated and well dispersed in the matrix network. Prepared catalysts and photocatalysts were very active in the targeted reaction; in particular, acid resin-based catalysts gave much higher conversion and selectivity in ethylene at very low temperature respect to catalysts prepared by conventional impregnation methods. References 1. Eggenhuisen T.M., Munnik P.. Talsma H., de Jongh P.E., de Jong K.P. J. Catal. 297, 2013, 306–313. 2. Lolli A., Albonetti S., Utili L.,Amadori R., Lucarelli C, Cavani F. Appl. Catal A 504, 2015, 408-419. 3. Costa A.L., Ortelli S., Blosi M, Albonetti S, Vaccari A., Dondi M J. Photochem. Photobiol. 276, 2014, 58– 64.

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Accessible acid sites in hierarchical architectures for Beckmann rearrangement

E. Gianottia, I. Milettoa, C. Ivaldia, S. Chapmanb, R. Rajab, L. Marchesea

aDepartment of Science and Technological Innovation and Nano-SiSTeMI Centre, Università del Piemonte Orientale, Viale T. Michel 11, 15121 Alessandria, Italy

bDepartment of Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton, SO17 1BJ. U.K

e-mail: [email protected] Hierarchical H-ZSM-5 and SAPO-34 catalysts have been obtained following both “bottom-up” and “top-down” approach. The nature, strength and accessibility of the acid sites present in the hierarchical materials were elucidated by means of a fine physical-chemical characterization using FTIR spectroscopy of adsorbed molecules together with SS MAS-NMR.

In this contribution, a post-synthetic desilication strategy in alkali media was followed to achieve hierarchical H-ZSM-51 and a bottom-up approach to obtain hierarchical SAPO-342,3. Both H-ZSM-5 and SAPO-34 possess acid active sites and are widely used as acid heterogeneous catalysts. In particular, a novel, facile, bottom-up approach was used to synthesize a hierarchical SAPO-34 acid catalyst that mitigates the use of sophisticated surfactants, instead using ordered mesoporous silica (MCM-41) with CTAB as both silicon source and mesoporogen. To get information on the nature, strength and the accessibility of the acid sites in the hierarchical zeotype catalysts, a fine physical-chemical characterization using FTIR spectroscopy of adsorbed probe molecules together with SS MAS-NMR was performed. In addition, structural and textural properties of the hierarchical zeolites were also explored by means of XRD and volumetric analyses. In this study, CO was used to assess the acidic properties of the hierarchical zeolites and bulky basic molecules as pyridine, 2,4,6-trimethylpyridine and 2,6-di-tert-butylpyridine, that cannot enter the micropores, were used to get information on the enhanced accessibility of the active sites. Probe-based studies are particularly pertinent in catalysis for establishing structure-property relationships. The hierarchical materials showed superior activity in the Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam (precursor of Nylon-6) with respect to the parent microporous systems. This superior catalytic activity can be explained by the overcoming of the diffusion constraints due to the introduction of mesoporosity, well documented by the volumetric analysis and by the enhanced accessibility of active sites. References

1. Erigoni, A.; Newland, S.H.; Paul, G.; Marchese, L.; Raja, R.; Gianotti E. ChemCatChem, 2016, 8, 3161–3169. 2. Miletto, I.; Paul, G.; Chapman, S.; Marchese, L.; Raja, R.; Gianotti E. Chem. Eur. J., 2017, 23, 9952-9961. 3. Miletto, I; Ivaldi, C.; Paul, G.; Chapman, S.; Marchese, L.; Raja, R.; Gianotti E. Chemistry Open, 2018, 7,

297-301 Acknowledgements: This work was funded by the European Union’s Horizon 2020 research and innovation program under grant agreement N. 720783 - MULTI2HYCAT.

Figure 1. Graphical representation of a hierarchical zeolite

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OSAM


Technical innovations for demanding applications of FT-IR spectrometry

D. Salia

aBruker Italia Unipersonale S.r.l., V.le V. Lancetti 43, 20158 Milano e-mail: [email protected]

Molecular spectroscopy is an important analytical area with wide impact and extent. In last decades applications related to material sciences and basic research have become more and more demanding about several topics, like the possibility to probe the THz spectral range with accessible instrumentations, to perform standard far field microspectroscopy down to the diffraction limit or fast spectroscopy for kinetics studies. Today all the latest technologies have been applied by Bruker to FT-IR Spectrometers, and for the first time a hybrid technology is used into commercial spectrometer to cover a really broad spectral range from UV to sub-THz. The new continuous wave (CW) technology will be presented, showing the unmatched performances for a benchtop spectrometer, based on FT technique. Also additional innovations will be presented as well, including the last optical bench launched on the market.

O01PP


Overall mass transfer coefficients and controlling regimes in open cell foams

Carmen W. Moncada Quintero, Giuliana Ercolino, Stefania Specchia Politecnico di Torino, Dept. of Applied Science and Technology, Torino, Italy


In many heterogeneous catalytic reactions, the overall rate of reaction is often limited by mass transfer processes, which include both the internal diffusion (at intermediate temperatures) and external diffusion (at sufficiently high temperatures) of components into and out of the catalyst, especially for highly exothermic or endothermic reactions such as combustion or steam reforming. Open ceramic foams are a promising alternative as structured catalyst supports due to faster mass/heat transfer at reasonable pressure drop and higher contact efficiency than honeycomb monoliths and, mainly, packed beds.1 In this work, we investigated the influence of catalyst loading (100-250mg) on the geometric properties of open ceramic foams, the relative importance of diffusion resistances (controlling regime), and the catalytic performance towards the complete oxidation of methane. Zirconia open cell foams (Zir-OCF) with 30 pore per inch (ppi) were coated with 3% Pd/Co3O4 as a catalyst towards the lean combustion of methane. The carrier (Co3O4) was coated on OCF by solution combustion synthesis (SCS) and the catalytic active phase (Pd) was deposited on the carrier by wetness impregnation (WI). During the tests, the reactor was fed with 100, 200, and 300 NmL min−1 (equivalent to a weight hourly space velocity, WHSV, of 30, 60, and 90 NL s−1 gcat

−1, respectively) of a gaseous mixture containing 1 and 0.5 vol.% methane in nitrogen, with an excess of oxygen. To simplify the problem of reaction-diffusion in the catalytic layer, we combined the internal (Shi) with the external (She) mass transfer coefficient to obtain an overall mass transfer coefficient (ShOv).2,3

Fig. 1. Various resistances (A) and controlling regimes (B) as a function of Temperature at WHSV=30, 1 vol.% of CH4 and 100mg of Co3O4. References

1. Thompson, C.R. Chem. Eng. J. 221 (2013) 44–54. 2. Joshi, S.Y. Chem.Eng. Sci. 64 (23) (2009) 4976–4991. 3. Gupta, N. Chem. Eng. Sci. 56 (2001) 4771–4786.

A

AB

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Boosting up renewable hydrogen: efficient titania-based photocatalysts for gas phase photoreforming

D. Zanardo a, A. Olivo a, E. Ghedini a, M. Signoretto a, M. Manzoli b, G. Cruciani c

a Dipartimento di Scienze Molecolari e Nanosistemi, CATMAT lab., Università Ca’ Foscari Venezia, via Torino 155,

30172, Venezia Mestre, Italy b Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, via Saragat 1, I-44100, Ferrara, Italy

c Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, via P. Giuria 9, 10125 Torino, Italy

e-mail: [email protected] Hydrogen, a useful chemicals and promising fuel, can be obtained from organic compounds (e.g. biomass-derived) and water through photocatalysis [1], and the process in nowadays termed as photoreforming. Nonetheless, reaction conditions and catalyst design should be tuned to get a reliable and efficient photocatalytic process. Gas phase conditions are less studied than liquid one but more interesting due to easy catalyst recovery and reduced light scattering losses [2]. Concerning catalyst development, titanium dioxide (TiO2) is certainly the most studied [3], but a promoter is usually added to improve its activity. Noble metals are usually used for this purpose [4], but non-noble ones (e.g. copper) have been proven to have a comparable activity [2] while having a remarkably lower cost. Throughout this work, a pristine commercail TiO2 (P25) was promoted with copper (II) oxide (CuO) through two different techniques: impregnation [5] and complex-precipitation (CP) [6], the latter using two different ligands as additives. Then, prepared photocatalysts were tested on a lab-scale reaction rig using an ethanol-water vapour mixture (1:3 ethanol-water ratio) at 60°C and UV light as energy source. Ethanol is known to be more difficult to completely convert to CO2 and H2 compared to other compounds like methanol or sugars [1,7]: we observed only acetaldehyde as H2 co-product, as reported by other gropus [2,8]. Copper addition was proved to increase hydrogen productivity ten-fold compared to pristine titania. Moreover, CP samples were 30% more active than impregnated ones, regardless of the ligand used in the synthesis. The best samples showed an apparent quantum yield (AQY) of about 60%. Transmission Electron Microscopy (TEM) on promoted TiO2 showed highly dispersed CuO particles on both impregnated and CP-prepared catalyst, although no remarkable differences were observed between the two samples. In conclusion, non-noble metal-based photocatalysts were developed and tested. Copper promotion on a commercial TiO2 showed a remarkable effect on catalytic activity and, in particular, CP method was proven to be a more effective synthesis technique than impregnation to boost up hydrogen production. References

1. Kawai, T.; Sakata, T. R. J. Nature. 1980, 286, 474-476 2. Ampelli, C.; Genovese, C.; Passalacqua, R.; Perathoner, S.; Centi, G. Appl. Therm. Eng. 2014, 70, 1270‐1275 3. Ma, Y.; Wang, X.; Jia, Y.; Chen, X.; Han, H.; Li, C. Chem. Rev. 2014, 114, 9987-10043 4. Daskalaki, V.M.; Kondarides, D.I. Catal. Today 2009, 144, 75-80 5. Olivo, A.; Trevisan, V.; Ghedini, E.; Pinna, F.; Bianchi, C.L.; Naldoni, A.; Cruciani, G.; Signoretto, M. J. CO2

Utiliz. 2015, 12, 86-94 6. Chen, W.-T.; Jovic, V.; Sun-Waterhouse, D.; Idriss, H.; Waterhouse, G.I.N. Int. J. Hydrogen Energy 2013, 38,

15036-15048 7. Chiarello, G.L.; Aguirre, M.H.; Selli, E. J. Catal. 2010, 273, 182-190 8. Taboada, E.; Angurell, I.; Llorca, J. J. Catal. 2014, 309, 460-467

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Photocatalytic production of hydrogen from carbohydrates

Elnaz Bahadoria, Antonio Tripodia, Ilenia Rossettia, Michela Signorettob, Gianguido Ramisc*

a Chemical Plants and Industrial Chemistry Group, Dip. Chimica, Università degli Studi di Milano, INSTM Unit Milano-Università and CNR-ISTM, via C. Golgi, 19, Milano, Italy

b CatMat Lab, Department of Molecular Sciences and Nanosystems, Università Ca’ Foscari di Venezia, INSTM Unit Venezia, Via Torino 155, Venezia, Italy;

c DICCA, Università degli Studi di Genova, INSTM Unit Genova, via all’Opera Pia 15A, Genova, Italy


The photocatalytic production of H2 from water is seen as a promising way for the storage of solar light into a clean energy vector. The direct water splitting is poorly efficient and a common solution to improve hydrogen productivity is to add an organic sacrificial agent, which may be oxidised more effectively than water. In this work we have selected as organic sacrificial agents some model carbohydrates that can be obtained by hydrolysis of cellulose or lignocellulosic material. The process conditions have been at first optimised using a 1.3 L photoreactor and changing the operating conditions, including pressure, temperature, catalyst amount and pH using glucose as model reactant and commercial TiO2 (P25 by Evonik) as catalyst. The temperature showed an important effect on hydrogen productivity, since at T 60°C high glucose conversion was observed, but with negligible hydrogen yield. By contrast, at higher temperature (80°C), the consecutive reaction paths to hydrogen were fulfilled leading to appreciable productivity of H2, CO and CO2 in gas phase. In some cases, also some ethane and ethylene were observed. Then, the screening of different catalytic materials was carried out under the best reaction conditions (P = 4 bar, T = 80°C, 0.25 g/L catalyst, 5 g/L glucose, pH = 5.5). The commercial titania was compared with one prepared by precipitation (TiO2) and one prepared by flame pyrolysis (FP). The samples were added with CuO in different loading (0.2 or 1 wt%), added by impregnation (I), deposition precipitation (D) or using citrate ions as complexing agents (C). The highest hydrogen productivity was achieved with 0.2 wt% CuO prepared by impregnation over the FP-prepared titania, which led to 5 mol H2 per hour per kg of catalyst. By looking at the performance during time, a constant productivity was observed for the whole duration of the test, without any evidence of deactivation.

Acnowledgements The financial contribution of MIUR through the PRIN2015 grant (20153T4REF) is gratefully acknowledged. I. Rossetti and E. Bahadori are grateful to Fondazione Cariplo and Regione Lombardia for financial support (2016-0858 – “Up-Unconventional Photoreactors”).

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Effective thermal conductivity in open cellular structures: a fundamental analysis of the effect of the geometrical properties and a comparison of

the performances

M.Bracconia, M.Ambrosetti a, M.Maestria, G.Groppia, E.Tronconia aLaboratory of Catalysis and Catalytic Processes, Dipartimento di Energia, Politecnico di Milano, Milano,Italy

[email protected]

Heat management and thermal control are key aspects in the design and operability of several catalytic processes. To overcome radial heat transfer limitations of common packed bed reactors, structured catalysts have been proposed as a suitable solution for the efficient management of strongly exo- and endothermic processes. Among these structures, open-cell foams and periodic open cellular structures (POCS) are considered the most promising candidates. They are random or ordered interconnected porous solid structures, whose repeated open cells are composed by solid struts and open windows. The totally interconnected solid matrix promotes high heat transfer rates, being the conduction in the solid matrix the main contribution to the heat transport. In this work, we

analyzed the heat conduction in the solid matrix in both structures by exploiting 3D numerical simulations carried out on virtually reconstructed structures, aiming to derive engineering correlations for the effective thermal conductivity. We generated the computational domain for the numerical simulations by means of accurate reconstructions of the geometries. Random open-cell foams are generated according a previously proposed methodology [1,2], whereas the computational domain for POCS are built from CAD files generated where the basic unit cell, i.e. cubic, diamond, tetrakaidekahedral (TKKD), are repeated in the space. The numerical procedure is assessed by comparing the effective heat transfer properties with literature data for open-cell foams as shown in Figure 1(a). A good agreement has been obtained for porosities higher than 0.85, while widely scattered experimental data are observed at lower porosity. Our results show that the main parameter controlling the heat conduction is the solid volumetric fraction. Moreover, the effect of different cellular structures, e.g. disordered foams, TKKD, cubic, diamond, is investigated. Figure 1(b) compares the heat conduction performances of foams and POCS. At high porosity, the open-cell foams shows poorer heat transfer compared to ordered structures. Conversely, the performances

of all the structures are similar at low void fractions. The performances of cubic and diamond cells are usually slighthly lower than the TKKD. As a whole, our analysis enabled to accurately describe the effect of the geometrical properties in open-cell foams and periodic open cellular structures enabling their rational design.

References [1] M. Ambrosetti et al., Chem. Ing. Tech. 2017 89 915-925. [2] M. Bracconi et al., Chem. Eng. J., 2017. 315 608–620. Acknowledgements: This project has received funding from the European Research Council under Grant Agreement no. 694910 (INTENT).

Fig 1. Effective thermal conductivity for

open-cell foams evaluated with numerical simulations and experimental activities

(a) and for several ordered and disordered cellular material (b)

(a)

(b)

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Water Photo-Electrolysis onto Highly Ordered Nanotube Arrays Based on TiO2 and Ta-oxy-N

F. Tavellaa, C. Ampellia, C. Genovesea, D. Giusia, S. Perathonera, G. Centia

aDepts. MIFT and ChiBioFarAm (Industrial Chemistry), University of Messina, CASPE/INSTM and ERIC aisbl, Messina, Italy

Solar energy utilization can help to tackle global warming by drastically reducing CO2 emissions and providing sustainable energy for the ever-growing world population. In particular, the production of solar fuels (e.g. H2) by water photo-electrolysis is one of the most attractive technologies to produce clean and sustainable energy [1]. In this context, we synthesized highly ordered TiO2 nanotube arrays by controlled anodic oxidation, under the application of a constant voltage and in the presence of fluoride-based electrolyte. The calcined nanostructured TiO2 samples were tested as photoanodes in a compact photo-electrochemical (PEC) device, designed on purpose to minimize overpotential inside the cell [2]. A careful study on the optimization of the synthesis parameters (i.e. applied voltage, anodization time) allowed to obtain the relationship between nanostructure properties (i.e. the length of the nanotubes) and catalytic performances, through the evaluation of the photo-conversion efficiency (also called solar-to-hydrogen -STH- efficiency). The main results have been summarized in Figure 1, evidencing for a 1 µm-thick catalytic layer a maximum H2 production rate of 22.4 mol h-1 cm-2 and an STH efficiency as high as 2.5%. This value is among the best ever reported insofar as PEC cells use undoped TiO2 photoanodes and in absence of external bias or sacrificial agents.

time, min

0 50 100 150 200 250 300

H2 e

volu

tion,

m

ol

0

100

200

300

400

500

600

(1) TNT/Ti 30 min(2) TNT/Ti 45 min(3) TNT/Ti 1 h(4) TNT/Ti 3 h(5) TNT/Ti 5 h

(3)

(1)(4)

(5)

(2)

STH = solar to hydrogen

Figure: H2 production rate and STH efficiency for TiO2 nanotubes with different lengths. In the attempt to improve catalytic performances in the visible light region, we also prepared Ta oxy-nitride nanotubes by anodic oxidation followed by ammonia treatment to replace partially O with N. The preliminary results are very promising in terms of reduced bandgap (1.9-2.5 eV) with respect to TiO2 (3.0-3.2 eV). Photo-catalytic tests on Ta-oxy-N nanotube arrays are under progress. References

1. Lanzafame, P., Abate, S., Ampelli, C., Genovese, C., Passalacqua, R., Centi, G., Perathoner, S. ChemSusChem, 2017, 10, 4409-4419.

2. Ampelli, C., Tavella, F., Perathoner, S., Centi, G. Chem. Eng. J. 2017, 320, 352-362. Acknowledgements: This work was funded by PRIN 2015 SMARTNESS project nr. 2015K7FZLH “Solar driven chemistry: new materials for photo- and electro-catalysis”, which is gratefully acknowledged.

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Lanthanum as a promoter for Al2O3 and Ni-Al2O3 catalysts G. Garbarinoa, P. Rianib, E. Finocchioa, M. Flytzani-Stephanopoulosc, G. Buscaa

a DICCA Department of Civil, Chemical and Environmental Engineering, University of Genova, Genova, Italy. b DIFar Department of Pharmacy, University of Genova, Genova, Italy.

c Department of Chemical and Biological Engineering, Tufts University, Medford (MA),USA. e-mail: [email protected]

The development of new and efficient catalysts for the conversion of renewable feedstock claims the need to design catalysts with suitable characteristics, improved stability and, in many cases, with tailored acido-basic properties. The aim of this work is to have a better understanding on Lanthanum addition to alumina and Ni-Al2O3 catalysts applicable to different processes, i.e. (bio)-ethanol to (bio)ethylene, (bio)hydrogen through ethanol steam reforming, tar abatement and CO2 methanation.

For (bio)ethylene production from bioethanol, we have performed a systematic study on both home-made catalysts (on a small pore alumina) and La-modified aluminas, recently commercialized by Sasol. The addition of lanthanum to -Al2O3 in small amounts stabilizes alumina with respect to sintering and loss of surface area. However, when higher amounts of lanthanum are impregnated (80% calculated as %wtLa2O3/wtAl2O3), bulk lanthanum containing phases form with an important decrease of surface area. 5%La2O3/Al2O3 (calculated as 5% wtLa2O3/wtAl2O3) catalyst retains a significant Lewis acidity and displays some new basic centers, thus providing strongest acido-basic couples. This catalyst, even if less active in ethanol dehydration than alumina, results to be even more selective to diethyl ether at partial ethanol conversion and to ethylene at high ethanol conversion than bare alumina, producing less high hydrocarbons and carbonaceous material during reaction [1]. Commercial La-Al2O3 with 1%wt and 4%wt La2O3 contain well dispersed La3+-O2- species or in the case of 4%wt small LaxOy clusters. From the catalytic point of view, lanthanum doping reduces also in this case the number of active sites for both ethanol dehydration and DEE cracking, confirming the behaviour observed for home-made catalysts [2]. For these materials, a progressive reduction of coke formation has been observed, suggesting that La doping might produce stable catalysts for ethanol dehydration to (bio)ethylene.

Lanthanum also acts as a promoter for Ni/Al2O3 catalysts used in ethanol and tar steam reforming processes, where the promoting effect has been attributed to an enhanced activation of water given by metallic nickel promoted by lanthanum species [3].

Recently, our group investigated 13%wt Ni-La/Al2O3 with different La2O3 loadings (0, 4, 14 and 37 wt%, denoted as NixLA) in CO2 methanation with the same conditions reported in [4]. The addition of La strongly improves catalytic activity in CO2 methanation at low temperature and the best methane yield, in parenthesis, is reached at 573 K and 55000 h-1 for Ni14LA (0.71) followed by Ni4LA and Ni37LA (0.53 and 0.52, respectively) and NiA (0.39). Summarizing, Lanthanum acts as a stabilizer for Al2O3 and it improves the performances in ethanol dehydration to ethylene. Moreover, it improves the activity of Ni/Al2O3 catalysts for both steam reforming and methanation reaction, in accordance to the micro-reversibility principle. References

1. Garbarino, G. Appl. Catal. B: Environ. 2017, 200, 458-468 2. Garbarino, G. Appl. Catal. B: Environ., 2018, accepted, published on the web 3. Garbarino, G. Appl. Catal. B: Environ., 2015, 174-175, 21-34 4. Garbarino, G. Int. J. Hydrogen Energy, 2015, 40, 9171-9182

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Development of La doped Ni-based catalysts for methane dry reforming

F. Menegazzoa, C. Pizzolittoa, E. Ghedinia, M. Signorettoa, A. di Micheleb

a CATMAT Lab, Department of Molecular Sciences and Nanosystems, Ca’ Foscari University Venice and INSTM RU of

Venice, via Torino 155, 30172 Venezia Mestre, Italy b Department of Physics and Geology, University of Perugia, Via Pascoli 1, 06123, Perugia, Italy


The catalytic reforming of methane with carbon dioxide, rather than steam, for the production of synthesis gas (CH4 + CO2 2H2 + 2CO ΔH°=+247,3 KJ/mol) has attracted a considerable interest in the past years for both environmental and commercial reasons. The major problems preventing commercialization of this process are the quick deactivation of the catalyst due to carbon deposition and the high endothermicity of the process. The focus is therefore the stabilization of nickel active phase in order to suppress side reactions and to reduce coke.

In particular, the aim of this work is the development of Ni-based catalysts supported on ceria that are active, selective and stable in methane dry reforming at low temperature conditions. To improve the properties of the support we have decided to add lanthanum. Indeed, this promoter could improve the thermal stability of ceria and at the same time increase the oxygen vacations on the carrier by modifying its redox and structural properties1,2.

With the purpose of optimize support-promoter interaction, we have investigated the synthetic approach for lanthanum introduction: i) incipient wetness impregnation of promoter into both calcined and not calcined support; ii) co-precipitation of promoter and support. After calcination of the doped support at 550 °C, the active phase was introduced on the material by impregnation in order to obtain 10 wt% Ni. Catalytic tests were investigated at temperatures between 400 and 550 °C for 48 hours. The samples were characterized by different techniques in order to understand their catalytic performances.

All the samples are active for methane dry reforming showing different activities and selectivity. At 400 °C the samples are less active but give higher H2 selectivity. As the temperature increases, there is an improvement in the activity and a change in the products distribution, which leads to a decrease in the H2/CO ratio.

It has been found that lanthanum introduction improves both catalytic activity and hydrogen yield. The technique of lanthanum impregnation on calcined ceria is the best one. Such technique allows on one hand a better dispersion of the active phase, which interacts more effectively with the support; on the other it allows structural modifications that involve the increase of the latex parameters and the improvement of the redox pump. These characteristics are reflected in the decrease in carbonaceous compounds during the methane dry reforming. Stability tests were carried out for 100 hours of time on stream. References 1. Capdevila-Cortada, M., Vilé, G., Teschner, D., Pérez-Ramírez, J., López, N., Appl. Catal., B 2016, 197, 299–312. 2. Liu, F., Zhao, L., Wang, H., Bai, X, Liu, Y., Int. J. Hydrogen Energy 2014, 39, 10454-10466.

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Sonochemical synthesis of Ni-Based catalysts for Ethanol Steam Reforming

A. Di Michelea, A. Dell’Angelob, N. Dimitratosc , G. Ramisd, I. Rossettib aDipartimento di Fisica e Geologia, Università di Perugia. Via Pascoli 1, 06123, Perugia. Italy

bChemical Plants and Industrial Chemistry Group, Dip. Chimica, Università degli Studi di Milano, INSTM Unit Milano-Università and CNR-ISTM, Via Golgi 19, Milano, Italy

cCardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CF103AT Cardiff, UK d Dip. di Ingegneria Civile, Chimica e Ambientale, Università degli Studi di Genova and INSTM Unit Genova, via

all’Opera Pia 15A, Genoa, Italy e-mail: [email protected]

Increasing attention is focused on hydrogen as a clean energy vector, because its oxidation is highly exothermal and the only product is water. Despite the huge potential benefits, the use of hydrogen is currently limited by the insufficient capacity of hydrogen storage technologies and by the safety issues related with its storage and transportation under mild conditions. Furthermore, nowadays 47% of global hydrogen is produced from natural gas, 30% from oil, 19% from coal and the remaining fraction via water electrolysis; therefore, ca. 96% of hydrogen derives from the conversion of fossil resources, which means a net co-production of CO2. New sources and new processes are needed to produce hydrogen in a sustainable way. Ethanol steam reforming (ESR) has received considerable attention, because ethanol is mainly obtained by renewable sources, it is simple to store, handle and transport because of its low volatility and toxicity. This process could be industrially advantageous, ideally yielding 6 moles of H2 per mole of ethanol reacted. Several metal-based catalysts have been proposed for the steam reforming of alcohols. Nickel is particularly attractive because of its high activity and selectivity in breaking C-C bonds and its lower cost if compared with noble metals [1]. In this study, MgAl2O4 was employed as support for Ni-based catalysts. Mg–Al mixed oxide supported Ni catalysts showed high activity in terms of H2 productivity and catalyst stability compared to nickel catalysts supported on pure oxides. MgAl2O4 was chosen as the preferred choice of support due to the following factors: (i) it is a slightly basic material, (ii) it exhibits moderate acidic and basic site strength and density, (iii) it limits the promotion of collateral reactions and, thus, minimises coke formation and therefore enhances catalyst stability. Therefore, we investigated a series of Ni/MgAl2O4 catalysts with different Ni loading and prepared with an ultrasound assisted technique to achieve high surface area and higher metal dispersion. Catalysts were characterized before and after catalytic tests by different techniques: FE-SEM, EDX, TEM, XRD, BET, TPR, MicroRaman and FT-IR. Ethanol Steam Reforming (ESR) tests were carried out in a continuous bench scale reactor operated at 625 °C, 500 °C and 400 °C, especially focusing at low temperatures for this application, aiming at process intensification. The effect of metal loading on activity and hydrogen selectivity was investigated, together with possible deactivating phenomena. Finally, hypotheses on the reaction mechanism were drawn on the basis of DRIFTS analysis.

References 1. Rossetti I., Biffi C., Bianchi C. L., Nichele V., Signoretto M., Menegazzo F., Finocchio E., Ramis G., Di Michele

A. Applied catalysis B. 2012, 117-118, 384-396.

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25000 20000 15000 10000 50000.0

2.5

5.018300

Kub

elka

-Mun

k

Wavenumbers [cm-1]

AUROliteAu/ZrO

2

18450

From biomass to value-added chemicals: microwave-assisted levulinic acid conversion over gold catalysts

M. Manzolia, S. Tabassob, G. Grilloa, F. Bucciola, F. Menegazzoc, M. Signorettoc, G. Cravottoa

aDepartment of Drug Science and Technology and NIS—Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via P. Giuria 9, Turin 10125, Italy.

bDepartment of Chemistry, University of Turin, Via P.Giuria 7, Turin 10125, Italy cDepartment of Molecular Sciences and Nanosystems, Ca’ Foscari University Venice and

INSTM Consortium RU Ve, Via Torino 155, 30170 Venezia Mestre, Italy. e-mail: [email protected]

Microwaves (MW) are currently applied as a non-conventional enabling technology to promote fast chemical transformations producing rapid internal heating, that has been hypothesized to originate from a direct interaction of the electromagnetic field with specific molecules, intermediates, or even transition states in the reaction medium1. Indeed, the debate is still open and focused on discerning among thermal effects, due to the rapid heating, and high bulk reaction temperatures reached under MW dielectric heating, and other specific or non-thermal effects. Such effects, which are not linked to a macroscopic change in reaction temperature, involve the non-uniform heating at the surface of heterogeneous catalysts and the production of hot spots by MW irradiation, resulting in non-equilibrium local heating localized at the surface of the metal nanoparticles present on the catalysts2. Levulinic acid (LA) is among the most promising platform molecules obtained from biomass and it can be converted into high value-added molecules that can be used as green solvents, biofuel additives, in pharmaceutical industry and in the synthesis of biopolymers3. In this study, we will focus on the MW-assisted LA hydrogenation over gold catalysts (commercial 1 wt% Au/TiO2 by AUROlite™ and 1.25 wt% Au/ZrO2 prepared by deposition-precipitation) to obtain -valerolactone (GVL) and 1,4-propandiol (1,4-PDO). LA hydrogenation was performed in water or without any solvent either by (i) H-transfer (using methanol, propanol or formic acid) or (ii) in the presence of molecular H2. In the former case, Au/ZrO2 gave lower conversion to GVL than Au/TiO2, but higher selectivity, reaching 100 % with formic acid as H-donor. However, the Au/TiO2 catalyst was able to convert completely the LA and to further reduce GVL to 1,4-PDO in the presence of 50 bar H2 already at 150 °C (4 h reaction time). Interestingly, the selectivity to 1,4-PDO was complete at 200 °C. Complete ethyl levulinate reduction to 1,4-PDO was obtained at 160 °C using 1,4-dioxane as solvent (6 h reaction time) with 60 bar H2 over a CuAlZn catalyst4. An extended characterisation, including HRTEM and XRD measurements, was carried out to establish structure activity relationships. Moreover, diffuse reflectance UV-Vis analysis (Figure 1) revealed the presence of Au nanoparticles, that have a more homogeneous size (~2 nm5) on Au/ZrO2, further pointing out a role played by the support.

References

1. Kappe, O.K., Pieber, B., Dallinger, D. Angew. Chem. Int. Ed. 2013, 52, 1088-1094. 2. Tsukahara, Y., Higashi, A., Yamauchi, T., Nakamura, T., Yasuda, M., Baba, A., Wada, Y. J. Phys. Chem. C

2010, 114, 8965-8970. 3. Rackemann, D. W., Doherty, W. O. S. Bioprod. Bioref. 2011, 5, 198-214. 4. Ren, D., Wan, X., Jin, F., Song, Z., Liu, Y., Huo, Z. Green Chem. 2016, 18, 5999-6002. 5. Hakeem, A. A., Zhao, Z., Kapteijn, F., Makkee, M. Catalysis Today 2015, 244, 19-28.

Figure 1. Diffuse Reflectance UV-Vis spectra of Au/TiO2 e Au/ZrO2.

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Tailoring hierarchical zeolites for catalysis by one-pot synthesis routes V. Crocellàa, M. Signorilea, F. Boninoa, E. Groppoa, P. Quagliottoa, G. Viscardia,

S. Bordigaa

a Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Torino, Italy. e-mail: [email protected]

Hierarchical zeolites are crystalline silicates or aluminosilicates possessing multiple levels of porosity (interconnected micro and mesopores).1 They exhibit improved catalytic properties with respect to the traditional ones: reduction of the steric limitations for converting bulky molecules, increase in the rate of intracrystalline diffusion and decrease in the deactivating processes.2 In the past years, the “top-down” or post-synthetic modifications, usually not involving the use of templates (e.g. dealumination and desilication), have been commonly adopted to obtain hierarchical zeolites. However, the limitations and drawbacks of these strategies have been the driving forces for the discovery of new routes, known as “bottom-up” or primary syntheses, which mostly involve the use of templates. Among these, the soft-templating procedure seems to be the most promising. In the present work, we employed different soft-templates for the synthesis of hierarchical zeolites (containing Al or Ti). A first series of attempts have been performed using a standard commercial template to induce mesoporosity together with a typical structure directing agent for the microcrystallinity generation. Unfortunately, these templates usually work in a competitive rather than in a cooperative manner and the formation of micropores is favored, whereas the mesoporosity, if present, is associated to the remaining amorphous silica matrix, whose crystallization is not completed. As reported in the literature, 3 the most effective way to avoid phase separation is the use of a two-in-one template, which has dual structure-directing abilities in two different length scales. For this reason, we decided to synthesize a mesoporous ZSM-5 zeolite, following the procedure reported by Ryoo and coworkers,4 with the final target to modulate this synthesis strategy to obtain a new hierarchical titanium silicalite-1 with ordered interconnected porosities. To this purpose, we synthesized a non-commercial dual template with hydrophilic multi-ammonium head groups covalently linked to long hydrophobic tails. With this surfactant, we were able to generate hexagonally-ordered mesostructures with crystalline microporous walls (see Figure 1). All the synthesized materials have been deeply characterized by means of different techniques.

Figure 1. TEM image (left) and N2 adsorption/desorption isotherm at 77 K (right) of the hexagonally-ordered mesoporous ZSM-5. References

1. Bae W. G., Kim H. N., Kim D., Adv. Mater., 2014, 26, 675–699. 2. Serrano D. P., Escola J. M., Pizarro P., Chem. Soc. Rev., 2013, 42, 4004–4035. 3. Liu Z., Hua Y., Wang J., Dong X., Tian Q, Han Y., Mater. Chem. Front., 2017, 1, 2195—2212. 4. Na K., Jo C., Kim J., Cho K., Jung J, Seo Y., Messinger R., Chmelka B., Ryoo R., Science, 2011, 333, 328–

332.

10 nm


Transfer Hydrogenolysis of lignin derived aromatic ethers promoted by heterogeneous Pd/Ni catalyst

Emilia Paonea, b, Rosario Pietropaoloa, Alina M. Balub, Rafael Luqueb,c, Francesco Maurielloa

a Dipartimento DICEAM, Università “Mediterranea” di Reggio Calabria, Loc. Feo di Vito, I-89122 Reggio Calabria,

Italy b Departamento de Quımica Organica, Universidad de Cordoba, Edificio Marie-Curie (C-3), Ctra Nnal IV, Km 396,

Cordoba, Spain. cPeoples Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya str., 117198, Moscow, Russia


One of the major challenges of modern refineries is the production of bio-chemicals and bio-materials from non-edible lignocellulosic biomass.1,2 Since the lignin sub-structure is characterized by large amounts of etheric bonds, catalytic hydrogenolysis has received strong attention, allowing the C-O bond breaking by adding molecular hydrogen.3 At the same time, CTH reactions represent a valid green alternative to the direct use of H2 in sustainable catalysis.4,5 In this contribution, the catalytic transfer hydrogenolysis (CTH) of diphenyl ether (DPE), benzyl phenyl ether (BPE) and 2-phenethyl phenyl ether (PPE) - as model molecules of 4-O-5, β-O-4 and α-O-4 lignin linkages - promoted by bimetallic Pd-Ni systems is reported. Pd/Ni (Pd loading of 3 wt%) catalysts were synthesized by using a simple and economic co-precipitation technique and its detailed physico-chemical characterization was performed by means of H2-TPR, XRD, TEM and XPS analysis. In presence of palladium as co-metal, an almost complete conversion of DPE was reached after 90 min at a temperature of 240 °C while the C-O bond breaking of BPE and PPE was achieved under milder reaction conditions. The investigated substrates were also tested in the presence of the analogous monometallic Ni catalyst: the presence of palladium as co-metal was proved to increase the catalytic activity in C-O bond cleavage as well as to lower the selectivity to aromatic ring hydrogenation. The catalytic tests on all possible reaction intermediates clearly show that, by using 2-propanol as H-source, the primary key step in the etheric C–O bond breaking is the hydrogenolysis cleavage while the hydrogenation process only takes place in a successive step. Moreover, it has been demonstrated that the hydrogenation of phenol formed from CTH is strongly influenced by the nature of the aryl groups that form the aromatic ether structure.

References 1. Besson, M.; Gallezot P.; Pinel, C. Chem. Rev. 2014, 114, 1827–1870. 2. Tuck, C. O.; Peŕez, E.; Horváth, I. T.; Sheldon, R. A.; Poliakoff, M. Science. 2012, 337, 695–699. 3. Ruppert, A. M.; Weinberg, K.; Palkovits, R. Angew. Chem. Int. Ed. 2012, 51(11), 2564–2601. 4. Wang, D.; Astruc, D. Chem. Rev. 2015, 115(13), 6621–6686. 5. Gilkey, M. J.; Bingjun, E. X. ACS Catalysis. 2016, 6, 1420–1436.

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Non Thermal Plasma Assisted Reactions for Chemical Processes Intensification and Environmental Applications

V. Vaiano, G. Iervolino, E. Meloni, A. Ricca, V. Palma

aDepartment of Industrial Engineering, University of Salerno, Fisciano (SA) ITALY. e-mail: [email protected]

In recent years, research on “non-thermal plasma technology” (NTP) has notably increased. The NTP is a gas ionized by an externally applied electric field. In these conditions the electrons, due to their small mass, are usually at temperatures of the order of 105 K, whereas background gas molecules are close to the room temperature. NTP can be generated in atmospheric pressure discharges-pulsed corona, pulsed glow discharge, micro-hollow cathode discharge, dielectric barrier discharge (DBD), RF discharge, microwave discharge, and generally contains ions, electrons, radicals or molecules with very high reactivity [1]. NTP exhibit higher selectivity compared to thermal plasmas, and is a very active research area devoted to the intensification of chemical processes, as well as to the environmental depollution [2]. The industrial interest of NTP lies into the easy formation of stable plasmas, its effectiveness, scalability and low operational cost. In this work, different applications of DBD generated NTP were investigated [3]. In particular, the research group of “Industrial Chemistry and Catalysis” at University of Salerno has started to study two different applications based on DBD reactors concerning: i) chemical processes intensification, both endothermic and exothermic, and ii) wastewater treatment. In this work we evaluated the performances of a DBD plasma assisted falling film reactor for the removal of organic compounds (methylene blue of phenol) in aqueous solution (Figure 1a). The influence of operating parameters such as applied voltage (7-30 kV), gas flow rate and its composition (air or oxygen) has been assessed. Results showed that in the same conditions, the NPT process is faster if compared with the UV and photocatalytic processes giving an almost complete discoloration and mineralization of methylene blue (Figure 1b) after only 5 minutes. In addition, some preliminary tests were performed to verify the feasibility of NTP in CO2 methanation catalytic reactor (Figure 1c). A stoichiometric mixture (H2/CO2 = 4) at room conditions was fed to the system, in which a 7 cm3 of commercial catalyst was loaded. The results, shown in Figure 1d, evidenced that the plasma-assisted reactor was able to activate the Sabatier reaction, since H2 and CO2 were effectively converted in CH4 (and steam). The system reached stationary conditions in few minutes also evidencing an impressive CH4 selectivity without CO formation along the test. References

1. Jiang, L. et al., J. Environ. Sci., 2017, 55, 266-273 2. Eid, A. et al, International Journal of Plasma Environmental Science & Technology, 2015, 9(2), 120-126. 3. Czapka, T. et al. , Przeglad Elektrotechniczny, 2017, 1(8), 190-193.

Figure 1: a) DBD reactor for water treatment; b) Methylene blue degradation using different processes; c) DBD reactor for gas phase catalytic reactions; d) behavior of reactants and products during reaction.

DBD REACTOR FOR WATER

CH4

H2

CO2 CO

a b

dc

Time [min]

O12PP


Hydrogen production and purification via methane oxyreforming coupled with a water gas shift membrane reactor

F. Basilea, S. Abateb, A. Fasolinia, E. Lombardia, G. Centib

a University of Bologna, Via Risorgimento, 4 Bologna, 40136, Italy

b University of Messina, Salita Sperone, 31, Messina, 98122 Italy e-mail: [email protected]

The development of an oxy-reforming process followed by integrated WGS and membrane separation reactor is a valuable route for small-scale hydrogen production, as it reduces the number of reactors and unities needed for the whole process. In particular the oxy reforming combines Steam Reforming and Catalytic Partical Oydation of methane in a configuration that feeds low amount of oxygen (O/C=0.21) and steam (S/C=0.7-1.5) and is characterized by short residence times (36-150 ms). In this way, it is possible to reduce the temperature gradients as the exothermic oxidation is compensated by the highly endothermic SR. The reforming outlet was submitted to a water gas shift membrane reactor, in order to increase hydrogen yield and purify it. The WGS catalyst was a Pt/Ce0.5Zr0.5O2 synthesized by microemulsion technique1,2 and was able to work on low steam/dry gas ratio and high space velocities. In particular, best results were obtained using in the first oxy-reforming step a Rh/Ce0.5Zr0.5O2 catalyst1. In the membrane reactor the WGS reaction was favored in every condition with respect to methanation, due to the decrease of the hydrogen partial pressure given by hydrogen separation through the membrane. Moreover, the overall carbon monoxide conversion by WGS was higher than those calculated at the equilibrium for a fixed bed WGS reaction in the same conditions. The integration with the membrane provided total hydrogen selectivity, although a not negligible amount was left in the retentate stream. At low GHSV (30000 h-1), the difference in hydrogen partial pressure between the two sides of the membrane at the end of the membrane reactor approached 0, indicating the complete exploitation of the separation driving force. Nevertheless, still high percentage of hydrogen was left in the retentate at 5 atm with more than 40% of hydrogen still in the retentate. The best performances were obtained at T=400°C, P=10 atm, GHSV=100000 h-1 and S/C=1,5 and provided a permeate stream characterized by a high flux (731.44 ml/min) of pure hydrogen, while only the 10% of hydrogen in the retentate (404.65 ml/min). The integrated membrane reactor was run for 200 hours.

Figure 1. Dry gas outlet composition before and after the membrane in the optimized conditions OR: Toven=750°C; P=10 atm; GHSV=100000h-1; S/C=1.5; WGS: T=400°C. References

1. Basile, F. et al. Journal of the European Ceramic Society, 2018, in press. 2. Martínez-Arias, A. et al. Langmuir. 1999, 15, 4796-4802.

O13PP


Catalisi: Come controllare un microflusso di gas o liquido attraverso i nostri

misuratori di portata! R. Fontanesi

aAffiliation of the first author, Roberto, Milano, Italia e-mail: [email protected]

Dal 1998 offriamo gli strumenti di misura più efficaci per il controllo dei fluidi. Grazie a un Know-how sempre crescente, operiamo in tutte le realtà produttive e industriali, dal settore chimico alle acciaierie, dai cantieri navali ai centri di ricerca universitari. I marchi che rappresentiamo sono una garanzia di precisione e affidabilità e ci permettono di operare con successo nel mondo della chimica industriale e della catalisi. In questa breve presentazione avremo il piacere di introdurvi nel mondo Bronkhorst che è in grado di offrire una gamma completa di strumentazione per questo settore:

• Misuratori e regolatori di portata massici termici per gas con un particolare focus al

nuovo modello della serie El-flow Prestige ® che viene offerte con precaricate 25 curve di calibrazione per 25 differenti gas e miscele degli stessi

• Misuratori di portata massici a effetto Coriolis in grado di gestire micro portate, al di sotto dei 5 gr/h, di gas e liquidi e che possono essere associati a valvole integrate o separate e a pompe per un dosaggio estremamente accurato e ripetibile

• Sistema CEM: generatore di vapore che associando un regolatore di portata gas, misuratore di portata liquido e un riscaldatore/generatore di vapore permette di mantenere sotto controllo tutte le variabili di processo: pressione, portata, temperatura (fino a 200°C) e grado di umidità relativa

Infine, sarà un occasione per presentare per la prima volta in territorio italiano le innovative pompe del costruttore Tedesco Flusys in grado di generare microportate di liquidi a pressione elevate, fino a 400 Bar (g). Anche queste pompe possono essere associate, mediante un PID integrato, ai misuratori di portata Coriolis garantendo in questo modo una corretta e adeguata analisi dei principali fattori in gioco.

OSPP


Contributi Orali Martedì 4 Settembre


Energy R&D at Eni: technologies for decarbonisation

Francesca Ferrazza

Eni S.p.A., San Donato Milanese (Mi), Italy ) .


Abstract Liquid carbon-neutral biofuels are largely considered a possible way to face the new energy needs without dramatically increasing the carbon dioxide concentration in the Earth atmosphere. Few technologies are currently applied to produce bio-fuels based on renewables, most of them based on first generation feedstock, in competition with the food, feed and land use. This contribution will be focused on the emerging technologies for the production of “advanced” biofuel starting from waste biomass including those under development by eni SpA. Considerable industrial achievements have been recently reported, for instance, in the hydrotreating of vegetable oils and animal fats (HVO). Ecofining HVO technology, jointly developed by eni/UOP, has been already applied by eni in the green refinery of Venice (Italy). In order to find alternative feedstocks, there is also significant interest for routes to transform cellulosic sugar (i.e., produced via a proper hydrolysis of lignocellulosic biomass) into microbial lipids. This fermentation would provide a possible way to overcome the productivity limitations of classic oleaginous crops. Even larger oil productivity can be achieved, by cultivation of photo synthetic microalgae, growing on carbon dioxide from industrial activities, power plants and natural gas wells, able to accumulate a significant amount of oils (triglycerides) as energy storage material inside the cell. Alternatively, diesel biofuels can be obtained by thermochemical transformation, such as pyrolysis, gasification and hydrothermal liquefaction of waste biomass followed by the upgrading of the resulting liquid or gaseous intermediates. As for photovoltaics, the company has started an important initiative called “Progetto Italia” to make use of Eni’s decommissioned industrial land to implement renewable energy projects. Eni has identified about 15 projects so far, with a total capacity of around 220 MWp from PV to be installed before 2022. Other activities Outside Italy, ENI has already started utility-scale PV projects in Pakistan, Egypt, Algeria, and Ghana with a total planned capacity of more than 200 MWp. Besides these activities, Eni is carrying out research projects on new generation photovoltaics, namely polymer- and perovskite-based solar modules, and luminescent solar concentrators. Some examples of demonstrators (e.g., smart window and inflatable OPV) will be shown. To guarantee continuity to electric energy supply and to remedy the issue of discontinuity, typical of renewable sources (solar, wind) Eni is also studying solutions for energy storage, in particular is developing original electrochemical systems for redox flow batteries. Finally, nuclear fusion may offer a power plant scale energy production with an almost unlimited fuel supply. Also it is safe; it has no emission of the harmful gas CO2, no long life radioactive waste and it is independent from the local weather and geographical conditions. Eni has stared at the beginning of 2018 a long-term collaboration with MIT and CSF Inc. aimed to demonstrate the feasibility of this technology.

KN3


THE FLAMMABILITY LIMITS OF H2S/CH4/AIR MIXTURES

G. Pioa, V. Palmab, E. Salzanoa a Dip. di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via U. Terracini 28, 40131

Bologna (IT) bDip. di Ingegneria Industriale, Università di Salerno, via Giovanni Paolo II 132, 84084 Fisciano, Salerno (IT)


The presence of Hydrogen Sulfide (H2S) in Methane (CH4) streams may change the chemical behavior and induce severe safety challenges when extracting hydrocarbons (sour gas) [1], in the biogas chain and in other industrial applications. Indeed, the combined effect of flammability and toxicity of such gases has the potential to increase the hazard level to critical value, and to aggravate the consequences for human and assets even at large distances from the release point. In this work, the Flammability Limits (FLs) for CH4 - H2S – Air mixture were evaluate by means of a fully validated, detailed kinetic model and Limiting Burning Velocity theory, which defines the Flammability Limits as the composition such that the Laminar Burning Velocity is equal to a threshold value SU,Lim given by the following equation:

(1)

where ρu and ρb are respectively the unburned and burned gas density, α is the effective diffusivity and g the gravitational acceleration. The effect of initial temperature, equivalence ratio and H2S content was evaluated by varying the temperature in the range 250 K – 325 K, thus simulating extremely low and high ambient temperatures, and by considering H2S concentration up to 15 %v with respect to CH4. Results are shown in Table 1. Table 1. Flammability limits in terms of %v/v as a function of initial Temperature for different H2S content. Mix 1) CH4: 99.25 %v; H2S: 0.75 %v; Mix 2) CH4: 98.50 %v; H2S: 1.50 %v; Mix 3) CH4: 85.00 %v; H2S: 15.00 %v.

LFL [%v] UFL [%v] TIN 325 K 300 K 275 K 250 K 325 K 300 K 275 K 250 KPure CH4 4.90 4.99 5.03 5.08 16.70 16.63 15.50 14.31 Mix 1 4.81 4.95 5.02 5.09 17.51 17.38 17.10 16.66 Mix 2 4.82 4.92 5.01 5.11 17.62 17.39 17.13 16.68 Mix 3 4.79 4.90 5.03 5.15 19.62 19.07 18.60 17.91 Pure H2S 4.42 4.60 4.95 5.30 35.60 35.00 33.02 30.00

Quite clearly, it was found that either LFL or UFL are strongly affected by temperature and concentration. These effects are particular relevant for the UFL, which shows a substantial decrease at lower temperature and a clear, non-linear variation with the increasing amount of H2S in the methane gas. The results may be usefully adopted in several offshore and onshore industrial applications, for the definition of safety distances, for the simulation of accidental scenarios and, overall, for the quantitative assessment of risks in the case of accidental release of sour gas. References

1. Barba, D., Cammarota, F., Vaiano, V., Salzano, E., Palma, V., Fuel. 2017, 198, 68-75.

O14AM


Thermal behaviour of Peracetic Acid for the epoxydation of vegetable oils in the presence of catalyst

C. Vianelloa, E. Salzanob, G. Maschioa

aDipartimento di Ingegneria Industriale, University of Padova, Via F. Marzolo 9, 35131 Padova (IT) bDipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Alma Mater Studiorum - Università di

Bologna, Via Terracini 28, 40131 Bologna (IT) e-mail: [email protected]

Peroxyacids are commonly used in chemical processing, synthesis and bleaching. Recently, they have been demonstrated to be very versatile for the epoxidation of unsaturated oil, aiming at the synthesis of polyepoxides (plasticizer, resins and adhesives). These processes are characterized by high yields and selectivity. However, due to their hazard and instability, the peroxy reactants are often obtained from the corresponding organic acid in situ by combination with hydrogen peroxide, in the presence of a mineral (sulphuric or phosphoric) acid as catalyst. Furthermore, the processes are highly exothermic (about 230 kJ/mol for each double bond) and therefore can undergo thermal runaway reaction leading to a dramatic rise in the reactor temperature and eventually to explosion. This work presents the study of the decomposition of peroxyacetic acid in aqueous phase by using a Thermal Screening Unit (TSu) and the effect of the presence of the acid catalysts was analyzed. The experimental runs are carried out in a TSu, a pseudo-adiabatic and Non Differential Thermal Analysis instrument: a spherical sample holder is placed in the oven. During the tests the temperature and pressure profile of the sample is observed. Scanning or isothermal test can be run. The decomposition has been performed with peroxyacetic acid (PAA), generated in situ, by reacting concentrated hydrogen peroxide and acetic acid (AA), in the presence or not of catalyst. Thermal screening tests of components and reaction mixtures are required to assess chemical hazard, as they are useful for the identification of process conditions under which a thermal explosion can occur, and for the definition of several safety parameters as the onset of decomposition temperature, the time and the pressure corresponding to the onset, the maximum of the spike for the divergent reaction and an indication of the heat of reaction. The aim of work is evaluated the safety parameters and estimated the pseudo-kinetic parameters, i.e. based on pseudo first-order reaction, by a sensitivity analysis. The experimental tests have shown the runaway behaviour of the decomposition of Peracetic Acid reactions. The safety parameters highlight the sudden and significant increment of the temperature and pressure. From the thermal and kinetic results, it is quite evident that Sulphuric Acid has a considerable catalytic activity, whereas Phosphoric Acid has a lower catalytic activity. References

1. Santacesaria, E. Chem. Eng. J. 2011, 173, 198–209 2. Salzano, E. Chem. Eng. Trans. 2012, 26, 39–44. 3. Vianello, C. Process Safety and Environmental Protection 2018, in press. 4. Vianello, C. Chem. Eng. Trans. 2015, 43, 237-2376.

O15AM


Toward a novel standard vessel for testing dust explosion

A. Di Benedettoa, R. Sanchiricob, V. Di Sarlib aDipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli

Federico II, Piazzale Tecchio 80, 80125, Napoli (IT) bIstituto di Ricerche sulla Combustione, CNR, Via Diocleziano 328, 80124, Napoli (IT)

In chemical processes, a high number of accidents are imputable to explosions of flammable dust or dust-gas/vapor in air causing failure to equipment, injuries and damages to people and surrounding environment. Protection from accidental explosion coming from dust-air or dust-gas-air mixtures necessarily requires prevention and mitigation measures. Such measures are based on the knowledge of the main parameters that characterize the flammability and explosion features of both dust-air and dust-gas-air mixtures. Measurement of the most important explosion and flammability parameters is performed according to standard procedures, in a standard explosion apparatus that consists of a closed steel combustion chamber with an internal volume of 20 l, spherical or cylindrical in shape. One of the major requirements of the apparatus is that it must be capable of dispersing a fairly uniform dust cloud in the vessel and of realizing a controlled turbulence level. Recent studies have shown that the standard procedure suffers from many issues. The main issue is the inability to control the turbulence level inside the sphere which varies in time, space and with the properties of the dust (Dahoe et al., 2001; Di Benedetto et al., 2013a; Hauert et al., 1994; Pu et al., 1990). Furthermore, it has been shown through CFD simulations that with the standard procedure/equipment it is not possible to generate a uniform dust-air cloud dispersion (Di Benedetto et al., 2013a; 2013b; Di Sarli et al., 2014). The third issue is that the method of dust injection in the sphere may cause severe particle fragmentation, thus changing the particle size distribution of the dust and altering its flammability and explosion features (Kalejaiye et al., 2010; Sanchirico et al., 2015). In this work, we show the effect of the method and equipment of testing on the values of the minimum explosive concentration (MEC). In particular, we show, through coupled CFD simulations and experiments, that the measurements according to the standard procedure in the standard equipment give MEC values significantly higher than the real values. All these results drive a novel equipment design for testing dust explosion. References 1. Di Benedetto A., Russo P., Sanchirico R., Di Sarli V., CFD Simulations of Turbulent Fluid Flow and Dust

Dispersion in the 20 Liter Explosion Vessel, AICHE J. 2013a Vol. 59, No. 7 pp.2485 2. Di Sarli, V., Russo, P., Sanchirico, R., Di Benedetto, A, CFD simulations of the effect of dust diameter on the

dispersion in the 20 l bomb, Chemical Engineering Transactions, Volume 31, 2013b, Pages 727-732 3. Di Sarli, V., Russo, P., Sanchirico, R., Di Benedetto, A. CFD simulations of dust dispersion in the 20 L vessel:

effect of nominal dust concentration, Journal of Loss Prevention in the Process Industries, 2014, 27 (1), pp. 8-12 4. Kalejaiye O, Amyotte PR, Pegg MJ, Cashdollar KL. Effectiveness of dust dispersion in the 20-L Siwek chamber.

Journal of Loss Prevention in the Process Industries. 2010; 23: 46-59. 5. Sanchirico R., Di Sarli V., Russo P., Di Benedetto A., Effect of the nozzle type on the integrity of dust particles in

standard explosion tests, Powder Technology, 279 2015 203-208 6. Pu YK, Jarosinski J, Johnson VG, Kauffman CW. Turbulence effects on dust explosions in the 20-L spherical

vessel. In Proceedings of 23rd International Symposium on Combustion. Pittsburgh, PA: The Combustion Institute. 1990: 843-849.

7. Dahoe AE, Cant RS, Scarlett B. On the decay of turbulence in the 20-liter explosion sphere. Flow, Turbulence and Combustion. 2001; 67: 159-184.

9. Hauert F, Vogl A, Radandt S. Measurement of turbulence and dust concentration in silos and vessels. In Proceedings of the 6th International Colloquium on Dust Explosions, Shenyang, PRC. 1994.

Acknowledgements: Authors acknowledge Mr. Andrea Bizzarro for his relevant support in the experimental work.

O16AM


Crosslinked Polymer Electrolytes Improving the Safety of Rechargeable Batteries

F. Bellaa, G. Pianaa, F. Colòa, M. Falcoa, G. Meligranaa, C. Gerbaldia

aGAME Lab, Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)


Safety of lithium-based batteries has attracted much media and legal attention. Therefore, all batteries carry a safety risk, and battery makers are obligated to meet safety requirements. Lithium-ion systems (and post-lithium technologies) are safe but - with millions of consumers - failures are bound to happen. Profoundly ion conducting, self-standing and tack-free ethylene oxide based polymer electrolytes are successfully prepared via a rapid and easily up-scalable free radical polymerization (UV/thermal curing). It can be an interesting alternative to produce polymer electrolytes, being highly advantageous due to its easiness and rapidity in processing, high efficiency and eco-friendliness as the use of solvent is avoided. The crosslinking produced during curing allows the incorporation of high amount of ionic liquids (e.g., imidazolium, pyrrolidinium) or tetraglyme and lithium salt (TFSI anion), leading to a material with remarkable homogeneity and robustness. The polymer network can efficiently hold plasticizers without leakage. Samples are thermally stable up to 375 °C under inert conditions, which is particularly interesting for application in Li-ion batteries with increased safety. Excellent ionic conductivity (>0.1 mS cm–1 at 25 °C), wide electrochemical stability (> 5 V vs. Li), stable interfacial properties and dendrite nucleation/growth resistance are obtained. The lab-scale Li-polymer cells assembled with different electrode materials (e.g., LiFePO4, Li-rich NMC, LiCoPO4, TiO2) show stable charge/discharge characteristics with limited capacity fading upon very long-term reversible cycling [1-3]. The overall remarkable performance of the novel polymer electrolytes postulates the possibility of effective implementation in the next generation of safe and durable secondary Li-based polymer batteries working at ambient and/or sub-ambient temperatures.

Fig. 1 Typical appearence of a cross-linked polymer electrolyte with truly elastic characteristics, used to replace flammable, liquid organic electrolytes.

1. Porcarelli, L.; Gerbaldi, C.; Bella, F.; Nair, J.R. Sci. Rep. 2016, 6, art. no. 19892. 2. Colò, F.; Bella, F.; Nair, J.R.; Gerbaldi, C. J. Power Sources 2017, 365, 293-302. 3. Nair, J.R.; Bella, F.; Angulakshmi, N.; Stephan, A.M.; Gerbaldi, C. Energy Storage Materials 2016, 3, 69-76.

O17AM


Rational design and synthesis of biodegradable renewable polyesters by exploiting biocatalysis

A. Guarneria, M. Cespuglia, V. Cutifania, C. Eberta, L. Gardossia

aUniversità degli Studi di Trieste, Dipartimento di Scienze Chimiche e Farmaceutiche, Trieste, Italy e-mail: [email protected]

In recent years, we have demonstrated that biocatalysts have the potential of adding higher

value to bio-based polymers by catalyzing the synthesis, modifications and degradation of polyesters that are not possible with conventional chemical strategies.1,2 Hydrolase enzymes can also catalyze the synthesis of structured, functionalized, and biodegradable polyesters through highly selective and benign synthetic processes. Notably, enzymes can catalyze the synthesis of polyesters with moderate MW (generally < 20.000 Da), which can be exploited in the preparation of pharmaceutical and cosmetic formulations. Prepolymers with functional groups can also be chemically modified using effective strategy for obtaining polymers with higher molecular weight. Itaconic acid represents an interesting bio-based monomer because the vinyl group offers a functional group ideally exploitable for the anchoring of biomolecules or further chemical modifications. Unfortunately, itaconic acid undergoes isomerization and crosslinking under conventional polycondensation conditions. Lipases can overcome this drawback by catalyzing polycondensation of dimethylitaconate at 50-70°C and under solvent-less conditions. Biocatalyzed polycondensation yields products having MW between 1000 and 2000 Da.3 The present study will illustrate the rational design and synthesis of polyesters of itaconic acid. Polyalcohol were selected on the basis of compuatational studies that elucidated the ability of lipase B from Candida antarctica to accept different olygomers as substrates and, more importantly, promote elongation.

Figure 1: Solventless synthesis of polyitaconate catalyzed by lipases and structural model illustrating the

structural basis of enzyme-olygomer recognition.

The study also disclosed the structural constraints that enable the functionalization of C=C bond of itaconic acid derivatives or, as an alternative, the degradability of polyitaconate in the presence of primary amines. Understanding the molecular basis of enzymes ability to accept polymers as substrates paves the way to new more effective strategies for polymers functionalization, degradation and recycling.

References

1. Pellis A., et al. Green Chem., 2017, 2017,19, 490-502. 2. Pellis A., et al. Biotechnol. J., 2016, 11, 642-647. 3. Ferrario V., et al. Adv. Synth. Cat., 2015, 357, 1763-1774.

O18AM


Sustainable production and enzymatic functionalization of microbial Polyhydroxyalkanoates

C. Pezzellaa, I. Corradoa, M. Vastanoa, A. Pellisb, B. Immirzic, G. Dal Poggettoc, G. Guebitzb,

M. Malinconicoc, G. Sanniaa aUniversità Federico II, Dipartimento di Scienze Chimiche, Napoli, Italy.

bAustrian Centre of Industrial Biotechnology GmbH, Tulln, Austria. cInstitute for Polymers, Composites and Biomaterials, Napoli, Italy


Polyhydroxyalkanoates (PHAs) are microbial polyesters attracting great interest as “green” alternatives to conventional petroleum-based plastics1. In this study, various Escherichia coli based production systems, were designed to enhance the accumulation of PHAs with high medium chain length moieties. Media optimization and system engineering were applied, yielding to the production of up to 260 mg/L of PHAs. Polymers characterization revealed a low grade of crystallinity and remarkable hydrophobic features. For further functionalization, a novel enzyme based strategy was developed. Lipase B from Candida antarctica (CaLB) was used to catalyze the terminal coupling of PHA with: i) dimethyl itaconate (DMI) in order to introduce reactive side chain vinyl moieties for easy coupling of functional molecules and/or ii) biocompatible polyethylene glycol (PEG) to tune polymer hydrophilicity. The functionalized polymers obtained in this study open new perspectives for the use of PHAs as biodegradable and biocompatible materials of choice for biomedical applications2. In view of total process sustainability, PHA production process has been coupled to the conversion of waste materials. The use of Waste frying oils (WFO) as raw materials sustaining PHA production will be presented. References 1. Tan, G.Y Angew. Polymers. 2014, 6, 706-754. 2. Vastano, M. Green Chem. 2017, 19, 5494-5504. Acknowledgements: This work was funded by Fondazione CARIPLO, Industrial Biotechnology Project BEETOUT – Sugar Beet biorefinery for the integrated production of biofuel and polyesters.

O19AM


Model analysis of a Plasma Enhanced Catalytic reactor for methane abatement in an automotive aftertreatment system

M. Molteni, A. Donazzi Laboratory of Catalysis and Catalytic Processes, Politecnico di Milano, Milano, Italy.


A one-dimensional model of a two-stage reactor for the Plasma Enhanced Catalytic (PEC) abatement of CH4 emissions is presented. The reactor is intended for use in automotive applications and consists of a chamber for the production of non-thermal plasma (NTP) followed by a catalytic packed bed with Pt/α-Al2O3 pellets[1]. 0.1% CH4 in humid air is supplied at varying input energy density (10 – 100 J/L) and inlet gas temperature (200 – 500°C). For the NTP process, the model solves conservation equations of mass and enthalpy for neutral, charged and radical species (73 total species). The formation of NTP is modeled with two additional equations for electron density and electron temperature[2]. The kinetic scheme for CH4 abatement includes the GRI-Mech[3] detailed set of radical reactions (325 steps) coupled with several sets of NTP reactions (107 steps), which include elastic collisions, direct ionization, dissociative ionization, excitation and attachment reactions[4,5]. The packed bed reactor is described with a 1D heterogeneous model based on a validated kinetic scheme. The interactions between NTP and heterogeneous catalysis within the porous matrix of the packed bed are rigorously accounted for. The kinetic scheme for plasma is verified on a-priori basis on dedicated literature results (Fig. 1A) and successfully extended to the analysis of the experimental results from the PEC system. The species concentrations, the gas temperature and the temperature of the solid are evaluated along the axis of the PEC reactor. Reaction path analysis reveals the rate determining step of the plasma mechanism and the modification of the heterogeneous kinetics by introduction of radical species. The model is also applied to investigate key-features of the PEC process under different operative conditions, such as the interplay between gas-phase and surface chemistry, the composition of the gas delivered to the catalytic bed, and the average temperature level reached in the system. The results highlight the crucial role of gas phase heating by plasma collisions in determining the conversion achieved in the PEC reactor, suggesting that a precise measurement of the temperature is necessary to characterize the performance and establish whether NTP is promoting the reaction thermally or chemically. An analysis of the energy input required to achieve the target CH4 conversion reveals that a close control of the heat management (Fig. 1B) is necessary to rationalize the measurements (e.g. dissipations, adiabaticity).

Fig 1. Panel A) comparison between CH4 conversion as a function of the NTP energy input with an inlet gas temperature of 450°C.

Panel B) simulated gas T profile along the plasma chamber evaluated under different thermodynamic conditions.

References 1. S. Da Costa et al, U.S. Patent 2008/0173534 A1, 2000. 2. A. Hurlbatt et al., Plasma Process and Polymers. 2017, 14, 1600138. 3. http://cumbustion.berkley.edu/gri-mech/version30/text30.html 4. https://nl.lxcat.net/home/ 5. J. T. Gudmundsson et al., Plasma Sources Sci. Technol., 2010, 19, 055008.

A B

O20AM


Synthesis of highly active Ru/Al2O3 catalysts and experimental investigation of internal diffusional limitations in CO2 methanation

A. Portaa, L. Falboa, C.G. Viscontia, L. Castoldia, L. Liettia, P. Deianab, C. Bassanob

aDipartimento di Energia, Politecnico di Milano, Milano, 20156, ITALY bENEA, Santa Maria di Galeria (Roma), 00123, ITALY


Carbon dioxide is the most abundant greenhouse gas and its utilization as carbon source is environmentally and industrially attractive. Among the proposed CO2 (re)utilization technologies, CO2 hydrogenation to methane through the Sabatier reaction is particularly appealing1. The highly exothermic CO2 methanation is limited by thermodynamics at the high temperatures required by conventional Ni-based catalysts. In these conditions, CO selectivity is also rather high. In this regard, Ru-based catalysts are of interest because are active at lower temperatures, allowing higher CO2 per-pass conversion with almost complete selectivity to methane2. Aiming at the optimization of the efficiency of the process at industrially relevant conditions, the effect of the size of the catalytic pellet on the catalytic performance has been investigated. For this purpose, γ-Al2O3 spheres of various diameters (100, 800 and 2300 μm) have been impregnated with 0.5 wt.% of Ru. Interestingly, the conventional incipient wetness impregnation method led to the preparation of eggshell catalysts on supports bigger than 100 μm. Eggshell catalysts are commonly employed in reactions limited by internal diffusional limitations and their preparation is rather complex, involving at least two impregnation steps3. The possibility to easily obtain an eggshell catalyst suggests a strong interaction between the Al2O3 support and the Ru precursor, which is deposited only at the outer shell of the spherical pellets. By changing this interaction via tuning the acidity of the impregnating solution with an inorganic acid, it is possible to effectively control the thickness of the catalytic layer, and homogeneously impregnated pellets could eventually be obtained. The impregnated pellets have been tested in conditions of industrial interest for CO2 methanation, in a kinetically controlled regime (i.e. after crushing and sieving). No differences in CO2 conversion nor in CH4 selectivity were observed between the powdered homogeneously impregnated pellet and the powdered eggshell pellet, indicating that the acid introduction does not affect the catalytic performance. Subsequently, homogeneously impregnated pellets have been tested to assess the role of internal diffusional limitations. No significant differences in the catalytic activity were observed when varying the dimension of the pellets, indicating the absence of intraporous limitations with a Ru loading of 0.5 wt.%. In order to increase the catalytic activity, the synthesis method and the activity tests have been repeated with a higher Ruthenium loading (5 wt.%). Interestingly, no differences in CO2 conversion nor in CH4 selectivity were observed between the powdered 0.5 and 5% catalysts at constant space velocity per gram of Ru working under chemical regime, indicating that the specific reactivity of the catalyst does not depend on the Ru loading. At variance, on large pellets on the homogeneously impregnated 5 wt.% Ru samples both conversion and selectivity are affected by internal diffusional limitations. Notably, the data collected under internal diffusional regime are relevant both in terms of mechanistic understanding of the Sabatier reaction and in view of the intensification of the process, and will be discussed in the presentation. References (1) Janke, C.; Duyar, M. S.; Hoskins, M.; Farrauto, R. Catalytic and Adsorption Studies for the Hydrogenation of

CO2 to Methane. Appl. Catal. B Environ. 2014, 152–153 (1), 184–191. (2) Frontera, P.; Macario, A.; Ferraro, M.; Antonucci, P. Supported Catalysts for CO2 Methanation: A Review.

Catalysts 2017, 7 (2), 59. (3) Wolan, J. T.; Gardezi, A. US8716170B2 Eggshell Catalyst and Method of Its Preparation, 2012.

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Kinetics of Hg oxychlorination and NH3-SCR over V/Mo/Ti: evidence of an inhibing effect of NH3 and a promoting effect of NO

A. Lanzaa*, A. Berettaa, R. Matarresea, L. Liettia, S. Alcove Claveb, J. Collierb

a Dipartimento di Energia, Politecnico di Milano, via la Masa 34, 20156 Milano, Italy. bJohnson Matthey Technology Center, Sonning Common, RG4 9NH, United Kingdom.

*e-mail: [email protected] This study investigates the kinetics of NH3-SCR and Hg oxidation over commercial V/Mo/Ti

catalysts, extending previous studies from the group and the literature [1-3]. The pursued goal is an improved kinetic description of the two reactions, based on the recognition of the redox nature of the common V-site. At this scope, independent experimental techniques and modelling analysis were combined to deepen the kinetics of the single reduction and oxidation steps in the two processes. A wide experimental campaign of NH3-SCR tests in micro-packed bed reactors allowed to recognize two important kinetic effects: (a) the inhibiting effect of NH3, in line with findings by Nova et al. [2]; (b) a promoting effect of NO on the re-oxidation step (in line with the theoretical findings by Arnarson et al. [3] who studied the redox cycle of NH3-SCR on V by DFT). The following rate expression was proposed and fully described the whole bulk of data:

The kinetics of Hg oxidation was studied over the same catalyst, at the pilot scale; experiments were performed at varying O2 content and with co-feed of NO and NH3. Remarkably, a weak O2 dependence, an inhibiting effect of NH3 and a promoting effect of NO were observed, in close similarity with the kinetics of NH3-SCR. This suggests that also the Hg oxidation can be described by a kinetic expression of the form:

This expression was implemented in the model of the multichannel reactor cell and Figure 1-3 show the comparison between experiments and model predictions. In conclusion, common features are clearly shown by the two chemical processes, which strongly supports the hypothesis of a common redox pathway. Notably, this work provides a generalized evidence of the NH3 inhibition (likely due to a spillover from the acidic to the redox sites, as proposed by [2]) and of the role of NO in the re-oxidation step, as intrinsic features of V-redox kinetics.

Figure 1) NO influence on Hg conversion. Figure 2) NH3 influence on Hg conversion. Figure 3) O2 influence on Hg conversion.

1. Usberti et al. Appl. Catal B: Environ. 193, 121-132, 2016. 2. Nova et al. AIChE J., 52, 3222-3233, 2006. 3. Arnason et al., J. Catal. 346, 188-197, 2017.

-ΔHHCl

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Chimica Industriale e Industria Chimica in Italia

Vittorio Maglia, aFederchimica, Milano, Italia

[email protected]

La Chimica Industriale e l’Industria chimica sono per eccellenza un ambito dove l’interazione tra Scienza e Industria, tipica della Chimica, deve essere ai massimi livelli. Ancor di più in Italia perché la specializzazione crescente dell’industria è nella parte finale della filiera chimica, cioè nelle specialities, che applicano la formulation chemistry e che contribuiscono all’innovazione e alla competitività di Industria e Costruzioni in Italia. Le sfide del mercato globale spingono tutti gli attori della filiera verso una ricerca più strutturata e questa è una sfida importante ma difficile per la media impresa italiana che per superare il vincolo dimensionale deve pensare a collaborazioni con il mondo scientifico, fin dal momento della formazione di giovani chimici. C’è poi la sfida della Sostenibilità che nella Chimica ora è molto legata, ma non solo al REACH e al rischio di dover sostituire molte sostanze.

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Technological and crystal-chemical aspects of nano-dispersions of hydrous silicates as cement additives.

Part 1: General and technological aspects

G. Artiolia, G. Ferrarib, M.C. Dalconia, L. Valentinia aCIRCe Centre, Dep. of Geosciences,University of Padova, Padova, Italy

bMAPEI R&D, Milano, Italy. e-mail: [email protected]

The use of calcium silicate hydrate (C-S-H) nanoseeds considerably accelerates the hydration process in cement pastes (Fig. 1) and induces a systematic modification of the paste texture and mechanical properties (Thomas et al. 2009, Nicoleau 2010, Artioli et al. 2014, Ferrari et al. 2015). The effect is attributed to the large increase in structurally-compatible surface enhancing the crystallization of the hydration products, which in turn is linked to the dissolution of the clinker phases and the saturation of the solution. This has relevant consequences in concrete and building technology because of improved durability and early strength development in the final materials. Commercial admixtures are already available, based on this technology.

References

1. Thomas, J.J., Jennings, H.M., Chen, J.J. J. Phys. Chem. 2009, C113, 4327–4334. 2. Nicoleau L. J. Transp. Res. Board 2010, 2142, 42–51 3. Artioli, G., Valentini L., Dalconi, M.C., Parisatto, M., Voltolini, M., Russo, V., Ferrari, G. Int. J. Mater. Res.

2014, 105, 628– 631 4. Ferrari, G., Russo, V., Salvioni, D., Surico, F., Artioli, G., Dalconi, M.C., Secco, M., Valentini, L. 11th Int.

Conference on Superplasticizers and Other Chemical Admixtures in Concrete. Ottawa, Canada, 12-15 July 2015. Conference Proceedings, 2015, SP-303-12, 167-181

5. Ferrari G., Russo V., Salvioni D., Artioli G., Dalconi M.C., Favero M., Valentini L., Secco M., Geppi M.: 14th Int. Congress on the Chemistry of Cement. Beijing, China 13-16 October 2015. Conference Proceedings CD, FSN 1050.

Acknowledgements: This work was supported through the collaboration agreement between MAPEI Spa and

PM4


Design and synthesis optimization of Prussian Blue materials for the removal of potentially radioactive cesium contaminants from aqueous solutions

C. Bisioa,b, F. Carniatoa, G. Gattia, A. M. Katsevc, S. L. Safronyukc, M. Guidottib

aUniversity of Piemonte Orientale, Alessandria, Italy bCNR - Institute of Molecular Sciences and Technologies, Milano, Italy

cMedical Academy, V.I. Vernadsky Crimean Federal University, Simferopol, Crimea, Russian Federation e-mail: [email protected]

The risk of a potential release of hazardous radionuclides into the environment is a topic attracting a growing attention, especially following some recent events linked to the accidental release of contamination from uncontrolled nuclear waste effluents or relevant incidents to power plants (e.g. Fukushima, 2014) [1]. Iron(III) hexacyanoferrate(II), Fe4[Fe(CN)6]3, also known as Prussian Blue (PB) had proved since the 1960s to be an ideal chelating agent for the removal of radioactive 137Cs contamination in aqueous media (waste effluents or biological fluids) [2]. The present study dealt with the design of a tuned and tailored synthesis strategy of PB, in order to maximize the capability of the lattice to remove radioactive species (Fig. 1a). The materials were fully characterized by textural (N2 adsorption isotherms), spectroscopic (XRD, FT-IR, DLS) and microscopic (SEM) techniques. It was then possible to optimize the physico-chemical features of the solid, in terms of specific surface area, pore volume and particle size (Fig. 1b). The contamination removal capability was tested in the abatement of non-radioactive 133Cs(I) from an aqueous solution (500 ppm) mimicking the enteric fluid and compared with a reference commercial decontamination sample (Fig. 1c). The optimized PB material removed after 1 h up to 85% of the Cs content vs. 63% for the reference sample, showing a noteworthy improvement with respect to the current state of the art. The toxicological properties of the two PB samples were evaluated by bioluminescence inhibition tests on two luminescent bacteria strains isolated from Black and Azov Seas (Vibrio fischeri F1 and Photobacterium leiognathi Sh1). Despite their difference in physico-chemical properties, the effects of the samples on bacterial luminescence were similar. In both acute and chronic toxicity tests, the solids exhibited only a weak inhibition in bacterial luminescence and a growth at concentrations up to 0.5 mg/ml. These results showed negligible (or a low) ecotoxicity for the PB compounds.

a) b) c)

Figure 1. a) PB lattice structure; b) particle size distribution as from dynamic light scattering analysis; c) Cs(I) uptake profiles from 500 ppm enteric solution. Red: optimized PB; black: reference PB sample. References

1. Yasunari, T. et al., PNAS 2011, 108, 19530-19534. 2. Nagy L. T., et al., J. Mater. Chem. 2012, 22, 18261-18267.

Acknowledgements: C. B. and M. G. gratefully acknowledge Mr. G. Cinquantini and NBCsystem for partial economic support.

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Cosmetic formulation: From the idea to a ready to market product

M. Signorettoa, E. Ghedinia, F. Menegazzoa

, E. Tanduoa a CATMAT Lab, Department of Molecular Sciences and Nanosystems, Ca’ Foscari University Venice and INSTM RU of

Venice, via Torino 155, 30172 Venezia Mestre, Italy .


The cosmetics industry is a science-driven and highly innovative sector, which makes large investments in research and development in order to obtain increasingly performing and sustainable products. The cosmetic formulation from the idea to a ready to market items involves a multidisciplinary and complex approach. In the proposed contribution, it will be presented a real example of research and development of innovative and Hi-Tech cosmetic products. In particular, the attention was focused on the development of a gel for the skin care, namely products to prevent skin aging, or designed to correct skin defects, such as blemishes and scars. At this purpose it was used the Drug Delivery Systems technology (DDS, controlled release of an active molecule), which is already known and widely used in the pharmaceutical field but not effectively exploited in cosmetics [1]. These systems help to optimize dosing, bioavailability and efficacy of active pharmaceutical ingredients already known and administered by traditional route. This approach, when used in cosmetics, allows to maximize the effectiveness of the active ingredients, overcoming the intrinsic limitations of the same (for example poor bioavailability) making the final products efficient and consequently more attractive for the consumer. The synthesis used is based on sol-gel method. A hybrid organic-inorganic network made of polysaccharides, inorganic derivates as silica or titania and fatty acid such as azelaic and glycolic acids was used as matrix. The formulation was optimized from time to time by adding the appropriate rheological modifiers and the appropriate excipient but avoiding the use of surfactants or preservatives. The active components were selected favoring natural or agri-food waste derivates whose efficiency will be maximized with the use of advanced technologies.

1. a) Signoretto, M., Ghedini, E., Nichele, V., Pinna, F., Casotti, D., Cruciani, G., Aina, V., Martra, G., Cerrato, G.A. Formulation of Innovative Hybrid Chitosan/TiO2 and Chitosan/SiO2 based Drug Delivery Systems,Multi-Volume SET (I-V) "Therapeutic Nanostructures, Volume 2: Drug Delivery”, Editor: Alexandru Mihai Grumezescu, Bucharest, 2016. b) Ghedini, E., Signoretto M., Nichele, V., Cerrato, G. Chem. Eur. J. 2012, 18, 10653-10660;

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The Role of Additives for Concrete Sustainability

M. Magistri, G. Ferrari, M. Mazzetti all of Mapei S.p.A., Milan, Italy


Construction industry is important to sustain the development of the modern society, in order to guarantee safe and comfortable buildings for people, modern and functional infrastructures and to promote the social development and the economy. Concrete is the primary material for these purposes. The global production of concrete is continuously increasing, most in the development countries, and reached 30,000 MIO Tons/year, corresponding to the consumption of 4,600 MIO Tons of cement1. Even if the embedded energy per unit is low, the CO2 emissions associated with the global concrete production is huge, more than 2,000 MIO Tons CO2/year2. Cement and concrete additives, originally developed to improve the technical performances of cement and concrete, nowadays play an important role also in reducing their environmental impact. In the present paper, the main issues of sustainability of cement and concrete additives, are described. Grinding aids additives are extensively used during the milling operations at the cement production plant to reduce the energy consumption and improving the cement performance. Accelerators and activators are essential for the production of concrete with high volume supplementary cementitious materials (SCMs), allowing the production of concrete with reduced carbon footprinting and excellent mechanical properties and durability. The last generation superplasticizers, based on polycarboxylate copolymers, allow the production of highly flowable concrete with reduced dosage of cement and high strength and durability. New additives allow to reduce the impact of waste in the concrete production, allowing the transformation of residual unused concrete to artificial aggregates, which can be used for the production of new concrete, representing an excellent example of circular economy. These new additives completely eliminate the dumping of returned concrete, and reduce substantially the emissions of CO2 associated with its disposal to landfill. Cement and concrete additives represent an important tool in the general strategy for reducing the environmental impact of concrete. References

1. Cembureau, Activity Report 2016, https://cembureau.eu/media/1635/activity-report-2016.pdf 2. Ashby, M., Materials and the Environment, 2nd ed., 2013, Elsevier.

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Design, formulation and characterization of anhydrous/highly concentrated surfactant mixtures

A. Fabozzia, L. Paduanoa,b, C. Jonesc, M.Di Serioa, G. D’Erricoa,b aDepartment of Chemical Science, University of Naples “Federico II”, Via Cinthia 4, 80126, Naples, Italy.

bCSGI (Consorzio Interuniversitario per lo Studio dei Sistemi a Grande Interfase) – Unit of Naples. cProcter and Gamble (P&G) Strombeek-Bever, Temseelan 100, BIC, Brussels.


A microstructural and dynamical investigation of aqueous mixtures of a new zwitterionic surfactant, synthesized at University of Naples “Federico II”, is presented. Particularly, N,N-dimethyl-2-propyl-1-amine-N-oxide (C10-branched) is compared with the commercial linear analogue N,N-dimethyldecyl-1-amine-N-oxide (C10-linear). The final goal is rationalizing the effect of the branches on the self-aggregation process of a zwitterionic surfactant. Nowadays, home care formulations for solid surfaces mainly contain two types of surfactants: the trialkylamine oxides (usually referred to as N-oxides) and the sodium alkyl ethoxysulfates. Specifically, the N-oxides control the foaming and cleaning properties of the final product. The N,N dimethylalkylamine oxides (CH3(CH2)n-1N+(CH3)2O-) are the most common N-oxide surfactants. In aqueous mixtures, these surfactants present an equilibrium between the protonated and the non-protonated form. At pH lower than the surfactant pKa, these molecules are protonated and behave as cationic surfactants, while in mixtures with a pH value higher than the pKa, they are in the non-protonated form and behave as nonionic (more precisely, zwitterionic) surfactants. The most investigated term of the series is N,N-dimethyldodecyl-1-amine oxide (C12-linear) [1]. In Figure (1) we report the binary phase diagram of C12-linear in water.

The phase diagram shows an extended micellar phase; however, liquid lyotropic crystalline phases, are stable above around 0.3 mole fraction. These phases, tend to limit the functionality of the detergent formulations. Consequently, during formulate production, a large amount of water must be included to assure mixture flow-ability. In this framework, we present the characterization of new N-oxides able to overcome these limitations. In principle C10-branched can enlarge the stability region of isotropic micellar aggregates. Thus, using branched species, it would be possible to formulate innovative surfactant mixture with higher active concentration, maintaining the feature to be ship-able, flow-able and stable. Their aqueous mixtures are characterized by surface tension, DLS, POM, QCMD, SANS, and rheology which allow the morphology of the aggregates to be deeply analysed.

References

[1] Lutton, E. J. Am. Oil Chem. Soc. 1966, 43, 28-30.

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Nanoporous crystalline polymers and industrial innovations Gaetano Guerra, Christophe Daniel, Paola Rizzo, Vincenzo Venditto

a Department of Chemistry and Biology “Adolfo Zambelli”, University of Salerno, Fisciano,I-84084, Italy

*Corresponding author: E-mail address: [email protected]

For two commercial thermoplastic polymers, syndiotactic polystyrene (s-PS)1-3 and poly(2,6-dimethyl-1,4-phenylene)oxide (PPO),4,5 crystalline phases including empty cavities of molecular size in their unit cell have been obtained and named nanoporous-crystalline phases. These nanoporous-crystalline phases exhibit density lower than the corresponding amorphous phases and are obtained by guest removal from co-crystalline host-guest phases, between a polymer host and low-molecular-mass guest.

Nanoporous-crystalline phases are able to absorb guest molecules also from very dilute solutions. Most studies have been devoted to s-PS, which exhibits two different nanoporous-crystalline phases, 1 and ,2 whose nanoporosity is organized as isolated cavities and channels, respectively. Physically crosslinked monolithic aerogels, whose physical knots are crystallites exhibiting a nanoporous crystalline form, will be also discussed.6,7 These aerogels present beside disordered amorphous micropores (typical of all aerogels) also all identical nanopores of the crystalline phases. Their outstanding guest transport properties combined with low material cost, robustness, durability and easy of handling and recycle make these aerogels suitable for applications in chemical separations, purification and storage.6,7 Most of the presentation will be devoted to possible industrial innovations based on materials with co-crystalline and nanoporous crystalline s-PS phases. In particular, applications of nanoporous films for active packaging of fruit and vegetable (by removal of ethylene and carbon dioxide),8 of nanoporous staple for removal of pollutants from water and air9 and of nanoporous aerogels as support for nanostructured catalysts,10 will be presented. References

1. C. De Rosa; G.Guerra; V. Petraccone; B. Pirozzi Macromolecules 1997, 30, 4147. 2. V. Petraccone; O. Ruiz de Ballesteros; O.Tarallo, P.Rizzo; G.Guerra Chem. Mater. 2008, 20, 3663. 3. M.R. Acocella, P. Rizzo, C. Daniel, O. Tarallo, G. Guerra, Polymer 2015, 63, 230 4. C.Daniel; S.Longo; G.Fasano; J.G.Vitillo; G.Guerra Chem. Mater. 2011, 23, 3195. 5. P.Lova; C.Bastianini; P.Giusto; M.Patrini; P.Rizzo; G.Guerra; M.Iodice; C.Soci; D.Comoretto ACS Appl. Mater.

Interf. 2016, 8, 31941. 6. C. D'Aniello, C. Daniel, G. Guerra, Macromolecules 2015, 48, 1187. 7. C. Daniel; M.Pellegrino; V.Vincenzo; S.Aurucci; G.Guerra Polymer 2016, 105, 96. 8. P. Rizzo; A.Cozzolino; A.R. Albunia; A.M. Giuffre; V.Sicari; L. Di Maio; C. Daniel; V. Venditto; M. Galimberti; G.

Mensitieri; G. Guerra J. Appl. Polym. Sci. 2018, 135. 9. C.Daniel; P.Antico; H.Yamaguchi; M.Kogure; G.Guerra Micropor. Mesopor. Mat. 2016, 232, 205. 10. V. Vaiano; O. Sacco; D. Sannino; P. Ciambelli; S. Longo; V. Venditto; G. Guerra, J. Chem. Technol. Biotechnol. 2014,

89, 1175.

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Designing properties of Pressure Sensitive Adhesives polymers by engineering their chemical structure

Marco Cerra*, Mario De Filippis*

VINAVIL SpA, Villadossola , Italy e-mail: [email protected]

Water based Pressure Sensitive Adhesives (PSA) are a class of polymers with average to low Molecular Weight (MW from 40.000 to 200.000 D)1 compared to conventional water based polymers that have a very high MW (over 1 Million), their film has to be tacky at room temperature and thanks to their visco-elastic structure are able to adhere to many surfaces and maintain a holding power (cohesion) sufficient to withstand weight of the substrate or other technical requirement. Generally are polymers based on acrylic esters obtained by radical polymerisation in aqueous media, the polymeric structure is very important and the interactions among of the polymer chains are of paramount importance to reach the desired tackiness and cohesion2.

After a brief introduction, we describe some phenomena that, properly exploited, can allow to further increase the final properties of the polymers. The study has been carried out by exploring the following concepts:

1) Morphology of the polymeric network (polymer chains) 2) Energy dissipation 3) Morphology of the latex particles 4) Morphology of the adhesive film

Of course these concepts, if properly exploited can lead to a massive improvements of the technical properties3. Then we report some examples, taken from literature, of acrylic PSAs with high peel adhesion and good cohesion mention, very shortly, the underlying phenomena responsible for that. In the second part we discuss the effect of water on PSAs and the strategies to improve water resistance Please use ACS settings for ChemDraw schemes. References

1. W.C. Dale, M.D. Paster, J.K. Haynes, Advances in Pressure Sensitive Adhesive Technology-2, 1995 C4, 88-89

2. James E. Mark , Burak Erman, Structures and Properties of Rubberlike Networks, OUP 1997, Ch 13 3. Andrew B. Foster, Peter A. Lovell, Michael A. Rabjohns, Control of adhesive properties through structured

particle design of water-borne pressure-sensitive adhesives, Polymer 50, 2009,1654–1670

Acknowledgements: This work is partially based on the studies of our past Senior Scientist Antonio Mader to whom we give our great gratitude.

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Structure-activity relationships of Zr-containing mixed oxides during catalytic hydrogenation of carbon oxides to methanol

G. Bonura, A. Mezzapica, F. Costa, C. Cannilla, F. Frusteri

CNR-ITAE, Via S. Lucia sopra Contesse 5, 98126 Messina, Italy e-mail: [email protected]

To date, several catalytic formulations were applied to develop an active, selective and stable methanol Cu-based methanol catalyst, but the most interesting results were obtained by incorporation of ZrO2 in the basic CuO-ZnO composition.1,2 In this work, a series of coprecipitated binary Cu-ZrO2 catalysts was found to show an interesting activity–selectivity pattern during methanol synthesis from catalytic hydrogenation of carbon oxides (PR, 20–30 atm; TR, 200–240°C; CO/H2=1:2 or CO2/H2=1:3). The effects of various pre–treatments as well as the copper/zirconia ratio on the structural and chemical properties of these samples were examined. The isoconversional Ozawa-Flynn-Wall method was apply to study the reduction behaviour, while the best fit modelling was used to establish the mechanism of copper reduction. Table 1. Phase modifications upon catalyst calcination and reduction.

SAMPLEdry calc@350°C calc@650°C

Phase Phase Crystal system Phase Crystal system

Cu‐ZrCuZr oxyhydroxides andCu2 (OH)2CO3 (malachite) +amorphous cubic ZrO2

CuO (tenorite) +ZrO2

Amorphous cubic

CuO (in air) or Cu2O (in Ar flow) +ZrO2

(surface CuO segregation on mixed oxide)Tetragonally distortedcubic (pseudo‐cubic)

Cu‐Zn‐Zr

(Cu,Zn)5(OH)6(CO3)2 (aurichalcite) +Zn5(OH)6(CO3)2 (hydrozincite) +Amorphous cubic ZrO2

CuO (tenorite) +ZnO (wurtzite)+ZrO2

Mixture of individual oxide phasesCuO (tenorite), ZnO (wurtzite)and Cu1–xZnxZr2O4 (spinel)

SAMPLEcalc@350°C/reduced calc@650/reduced

Model reduction Model reduction

Cu‐Zr&

Cu‐Zn‐Zr

Two different Cu2+ species,reducing independently:

AB1st order Prout–Tompkins

CD1st order Prout–Tompkins

ABCFirst stage: 0th‐order

Second stage: 1st order Prout–Tompkins(reduction of surface CuO segregated on surface)

H2 reduction@ 300°C

As reported in Table 1, surface reconstruction, re–crystallization and phase segregation phenomena in dependence of the conditions of catalyst activation (i.e., pre–treatment atmosphere and temperature) account for defined kinetic models of CuO reduction. The productivity to methanol in CO hydrogenation process followed the row of oxide precursors: tetragonal Cu–ZrO2 << amorphous Cu–ZrO2 << wurtzite–like Cu,Zr–ZnO, while the specific productivity to methane changed in the opposite manner. In CO2 hydrogenation, no noticeable amount of methane was detected, while introduction of Zn resulted in a higher methanol productivity. After calcination at 650°C, the ex–tetragonal Cu–ZrO2 sample exhibited an increased specific rate of CO2 conversion, but with a lower MeOH selectivity, being activity in WGSR even stronger enhanced. References

1. Minyukova T.P., Khassin A.A., Yurieva T.M., Kinet. Catal., 2018, 59, 112–122. 2. Bonura G., Cordaro M., Cannilla C., Arena F., Frusteri F., Appl. Catal., B, 2014, 152-153, 152–161.

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Valorizzazione dell’alginato via aqueous phase reforming per la produzione di idrogeno

G. Pipitonea, D.Toschesa, S. Bensaida, R. Pironea

aDepartment of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin,

Italy. e-mail: [email protected]

L’aqueous phase reforming (APR) di composti ossigenati è un processo molto studiato negli ultimi anni per la produzione di una miscela di gas ricca in idrogeno. Le molecole principalmente investigate sono dei semplici composti modello come glicole etilenico, glicerolo, sorbitolo. Obiettivo del lavoro è stato concentrarsi su una molecola più complessa, l’alginato, un carboidrato presente in abbondanza nella parete cellulare esterna delle macroalghe. Nell’ottica di sviluppo del concetto di bioraffineria, è infatti fondamentale provare ad ottimizzare lo sfruttamento dell’intera biomassa. La ricerca mira quindi a contribuire a riempire quel gap investigando una molecola abbondante nella biomasssa acquatica, andando oltre lo studio dei composti modello. L’APR di una soluzione diluita di alginato è stato effettuato a 225 °C in un reattore batch. I test sono indicati riportando la concentrazione in peso della soluzione di partenza (0.5, 1, 2%) e la quantità di catalizzatore utilizzato (0.8 o 0.4 g); quando è stato analizzato l’effetto del pH, il valore iniziale è stato inoltre indicato. In tabella sono riportati alcuni dei risultati ottenuti, evidenziando l’influenza di alcune condizioni di reazione sulle performance del processo. Si sottolinea come il test non catalitico abbia portato a una conversione del carbonio in fase gas pari al 7,5% (definita come il rapporto tra le moli di carbonio in fase gas e le moli di carbonio nel substrato); la presenza del catalizzatore (test 1% 0.8) ha aumentato la conversione fino al 20.4%. Questo è attribuito alla capacità del Pt di promuovere la rottura del legame C-C. L’aumento della conversione è combinato con una maggiore selettività: questa può essere dedotta dal rapporto H2/CO2, che aumenta da 0.21 nel test non catalitico a 0.57 in presenza del catalizzatore. Si osserva che dimezzando il loading di catalizzatore diminuisce la conversione del carbonio a gas mentre vi è un aumento della selettività. Pertanto, sembra che sia necessario trovare un valore ottimale nel loading del catalizzatore per massimizzare complessivamente la resa in idrogeno1. Nello studio dell’influenza della concentrazione si è notato come lavorare con soluzioni più concentrate porti a una costante diminuzione della conversione del carbonio. Questo risultato è coerente con quanto riportato in letteratura1: si ritiene infatti che l’aumento della concentrazione favorisca reazioni omogenee (non catalitiche) in fase liquida. È stato riscontrato un effetto benefico all’aumentare del pH. Come riportato in Tabella 1, maggiore è il pH maggiore è la selettività, con una diminuzione meno importante della conversione del carbonio, portando globalmente a una maggiore resa in idrogeno. Le performance ottenute nelle condizioni di pH acido possono essere attribuite alla possibilità che l’alginato subisca reazioni di deidratazione (catalizzate in ambiente acido), e quindi a idrogenazione (producendo un alcol) con una conseguente riduzione della produzione globale di idrogeno. References

1. Luo, N.; Fu, X.; Cao, F.; Xiao, T.; Edwards, P. P. Fuel 2008, 87, 3483–3489.

Table 1. Principali risultati ottenuti nell’APR dell’alginato (tempo di reazione: 4h)

Test Conversione del carbonio in fase

gas

H2/CO2

No cat 7.5% 0.21 0.5% 0.8 25.9% 0.44 0.5% 0.4 21.9% 0.57 1% 0.8 20.4% 0.55 1% 0.4 18.6% 0.63 2% 0.8 15.3% 0.46 2% 0.4 13.8% 0.48

1% 0.8 pH = 3 24.3% 0.09 1% 0.8 pH = 12 19.9% 0.5

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Figure 1 HMF oxidation pathways

Cooperative effect between Au, AuPd and NiO for the base-free oxidation of HMF

D. Bonincontroa,d, A. Lollia, A. Villab, L. Pratib, N. Dimitratosc, F. Cavania, S. Albonettia

aDepartment of Industrial Chemistry “Toso Montanari”, Università degli studi di Bologna, Bologna, 40136, Italy bDepartment of Chemistry Università degli studi di Milano, Milano, 20133, Italy

cCardiff Catalysis Institute, School of Chemistry, Cardiff University,Cardiff CF10 3AT, UK dCPE Lyon, C2P2, Université de Lyon1 UCBL, 69616, Villeurbanne, France


The depletion of fossil-derived resources and the need to decrease the emission of green-house gases led scientists to look for sustainable materials to replace the already existing fossil-derived ones. For instance, 2,5-furandicarboxylic acid (FDCA) has been pointed out as the bioderived counterpart of terephthalic acid for the synthesis of polyesters. In fact, FDCA could be obtained by means of selective oxidation of 5-hydroxymethylfurfural (HMF), a bio-derived platform molecule produced by glucose hydrolysis. HMF oxidation (Fig.1) is usually performed in batch reactor using water as solvent, oxygen as oxidant and supported metal nanoparticles (NP) as catalysts. Supported AuNPs and AuPdNPs have been found to be suitable catalyst in the conversion of HMF into FDCA1, but considerable amount of inorganic bases is needed to reach good conversion. Recently, it has been demonstrated the possibility of oxidizing aromatic and aliphatic alcohols under base free conditions using metal supported nano-sized nickel oxide (nNiO) catalysts2. In the present study, Au, and AuPd nanoparticles (Au:Pd metal molar ratio equal to 6:4) were deposited on nNiO and their catalytic behaviour was tested in the liquid-phase oxidation of HMF in base-free conditions.

The oxidation of HMF performed in the presence of the bare nNiO demonstrated the inability of the support to catalyse the reaction (Fig.2). On the contrary, the results obtained using Au/nNiO sample demonstrate that, even without the addition of the base, the 71% of HMF is converted after 6h of reaction with 25% of yield in FDCA. The preparation of a bimetallic AuPd system led to an increase of the activity (95% of HMF conversion and 69% FDCA yield), confirming that the alloyed bimetallic structure enhances catalyst performance as already reported for other supports1. Pd/nNiO did not show any relevant catalytic activity. The reaction mechanism studies and the spent catalyst analysis proved that DFF has a poisoning effect on the Au/nNiO catalyst performances, which is avoided by using the alloyed AuPd/nNiO.

In conclusion, an environmentally benign route to FDCA was designed, being AuPd/nNiO the best catalyst among the tested ones. References

1. Lolli, A.et al., Applied Catalysis A: General 2015, 504 (Supplement C), 408-419 2. Villa, A.et al. ChemCatChem 2011, 3 (10), 1612-1618

FDCAFFCA

DFF

HMFCA

HMF

Figure 2 HMF conversion and products yield for Au, and Au/Pd catalysts supported on nNiO.

Reaction conditions: 90°C, 6h, 10 bar O2,. Legend: ■ HMF, ■ HMFCA, ■ FFCA, ■ FDCA, ■ DFF.

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Contributi Orali Mercoledì 5 Settembre


Unravelling Surface Basicity and Bulk Morphology in N-doped 2D & 3D Carbon-based Materials for the Steam- and O2-Free Dehydrogenation Catalysis

G. Giambastiani,a,b G. Tuci,a C. Pham-Huu,b L. Luconi,a A. Rossina

a Institute of Chemistry of OrganoMetallic Compounds (ICCOM-CNR), Sesto F.no, Florence, Italy. b Institute of Chemistry and Processes for Energy, Environment and Health (ICPEES-CNRS), Strasbourg, France.

e-mail: [email protected] The last years have witnessed a wonderful technological renaissance that has boosted the development of light-heterodoped carbon-based nanomaterials as metal-free systems for a number of key industrial catalytic transformations. With a styrene (ST) global demand approaching 25 million tons per year, the ethylbenzene (EB) dehydrogenation to ST is nowadays one of the most challenging processes at the core of polymer synthesis. The current technology for ST production is a highly energy-demanding process that uses a large amount of steam and it is typically promoted by a K-Fe2O3 catalyst (K-Fe) at temperatures between 580 and 630 °C. Despite the general process feasibility, K-Fe lists the classical disadvantages of metal-based heterogeneous catalysts: e.g. a drastic deactivation/passivation due to the rapid generation of “coke” deposits and metal leaching or structural collapse occurring under harsh operative conditions. Carbon-based systems as such or in the form of heterodoped materials are known to catalyze the direct dehydrogenation reaction (DDH) with superior performance in terms of activity and selectivity compared to K-Fe.1 However, some key issues related to the complex puzzle of their physicochemical and morphological properties still remain to be addressed.2 The role of the surface basicity in N-doped carbons on DDH selectivity and catalyst stability on stream still remains a matter of debate within the scientific community. In this contribution, we describe a class of microporous, N-doped 3D and 2D systems as catalysts with superior activity and stability in the steam- and oxygen-free DDH of EB to ST. Selected materials from this series (Covalent Triazine Frameworks - CTFs) have unambiguously shown superior activity and remarkable selectivity in the ST production compared with other carbon- and/or metal-based benchmark systems of the state-of-the-art (Figure 1).3 A control of their chemico-physical properties and composition has unveiled for the first time the role of the chemically accessible surface basicity as a key factor for the inhibition of the catalyst deactivation, typically caused by the formation of coke deposits. Such a result paves the way to the rational design of effective and stable catalytic materials for the process. References

1. a) Zhang, J.; Su, D. S.; Blume, R.; Schlögl, R.; Wang, R.; Yang, X.; Gajović, A. Angew. Chem. Int. Ed. 2010, 49, 8640-8644. b) Ba, H.; Luo, J.; Liu, Y.; Duong-Viet, C.; Tuci, G.; Nhut, J.-M.; Nguyen-Dinh, L.; Ersen, O.; Su, D. S.; Giambastiani, G.; Pham-Huu, G. Appl. Catal. B-Environ. 2017, 200, 343-350.

2. Ba, H.; Liu, Y.; Truong-Phuoc, L.; Duong-Viet, C.; Nhut, J.-M.; Nguyen, D. L.; Ersen, O.; Tuci, G.; Giambastiani, G.; Pham-Huu, C. ACS Catal. 2016, 6, 1408-1419.

3. Tuci, G.; Pilaski, M.; Ba, H.; Rossin, A.; Luconi, L.; Caporali, S.; Pham-Huu, C.; Palkovits, R.; Giambastiani, G. Adv. Funct. Mater. 2017, 27, 1605672.

Acknowledgements: This work was funded by TRAINER project (DGPIE/MOPGA/2017-589) “Catalysts for Transition to Renewable Energy Future” and SMARTNESS project (2015K7FZLH) “Solar driven chemistry: new materials for photo- and electro-catalysis.”

Figure 1. A vs. A’ DDH of EB with CTF-ph and K-Fe catalysts at increasing reactor temperature: cat. 300 mg; 2.8 vol.% of EB in He at 30 mL min-1; temperature range: from 550 to 600°C.

KN4


Sustainable microwave-assisted processes for biomass valorization

S. Tabassoa, G. Grillob, F. Mariatti,b E. Calcio Gaudino,b Maela Manzoli,b G. Cravottob a Department of Chemistry, University of Turin, Via P.Giuria 7, Turin 10125, Italy.

b Department of Drug Science and Technology and NIS—Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via P. Giuria 9, Turin 10125, Italy.

. e-mail: [email protected]

The diminishing availability of fossil sources has stimulated the search for alternative means to produce energy and chemicals. Lignocellulosic biomass (LB) is the most abundant renewable source of biofuels and chemical compounds. Among LB, agricultural wastes are a valuable feedstock for the production of platform chemicals, as they do not compete with foodstuffs. In the search for sustainable processes for biomass conversion, microwaves (MW) represent an efficient energy source, enabling energy saving and process intensification.1 Indeed, the peculiar properties of MW as a volumetric and selective dielectric heating strongly promote chemical modifications reducing the reaction time and temperatures, and improving selectivity. In this presentation, various MW-assisted processes for the valorization of all the components of LB are described. In particular, the cellulose fraction of agricultural waste was converted into monosaccharides, levulinic acid or lactic and glycolic acid through a flash MW-assisted conversion. These different products were obtained selectively by simply changing the temperatures and/or the catalytic system. Levulinic acid was produced with high selectivity in acidic conditions and was then hydrogenated to γ-valerolactone (GVL) on Pd/C, through a new solvent-free protocol under MW.2 GVL was then used for the deconstruction of the lignocellulosic biomass itself, promoting the separation of lignin and hemicellulose from levulinic acid under acid conditions. On the other hand, a flash catalytic conversion using divalent metal cations afforded lactic and glycolic acids. The batch protocol was then adapted to a flow process, paving the way to scale up. The C2 and C4 units thus obtained were directly used for a MW-assisted polycondensation affording oligomers in good yields with a solvent- and catalyst-free protocol.3 A process for the valorization of the lignin portion of biomass is also presented. Vanillin and syringaldehyde were obtained after catalyst-free oxidative depolymerization of native lignin using oxygen or air as oxidants under MW irradiation. The biomass processing afforded cellulose as the solid residue for further valorization. References

1. Tabasso, S., Carnaroglio, D., Calcio Gaudino, E., Cravotto, G. Green Chem. 2015, 17, 684-693. 2. Tabasso, S., Grillo, G., Carnaroglio, D., Calcio Gaudino, E., Cravotto, G. Molecules, 2016, 21, 413-422. 3. Carnaroglio, D., Tabasso, S., Kwasek, B., Bogdal, D., Calcio Gaudino, E., Cravotto, G. ChemSusChem, 2015, 8,

1342-1349.

Acknowledgements: This work was funded by University of Turin (Fondi Ricerca Locale)

O23AM


A comparison among various strategies to boost the performance of TiO2-based photocatalysts

S. Scirèa, R. Fiorenzaa, L. D’Ursoa, P. Mineoa, G. Compagninia, M. Bellarditab, L. Palmisanob

aDipartimento Scienze Chimiche, Università di Catania, Viale A. Doria 5, 95125 Catania, Italy b DEIM, Università di Palermo, Viale delle Scienze, 90128 Palermo (Italy).


Since its application in water cleavage using a TiO2 photoanode in 1972 [1] photocatalysis attracted great interest as green technology. Photodegradation of aqueous or gaseous pollutants and production of clean fuels by photocatalytic water splitting or CO2 photoconversion have been the hottest topics. TiO2 is the most used photocatalyst due to its non-toxicity, good stability and low cost. However, there are still some drawbacks to a wide application of TiO2, such as the wide band gap, the fast recombination of photo-generated electron-hole pairs and the large overpotential for water splitting leading to low photocatalytic efficiency. Therefore, many efforts have been aimed at enhancing the TiO2 photoefficiency, enlarging the effective photocatalytic surface, forming Schottky junctions or heterojunctions, and engineering the band structure with structural or chemical modifications. Here we compare different strategies to modify the chemico-physical properties of TiO2 investigating the effects of these changes on the photocatalytic performance both in the H2 production by water splitting and in the photodegradation of aqueous pollutants. In the first approach we coupled TiO2 with another oxide (CeO2) and added metals (Au or Ag) as dopants. The enhanced redox properties of CeO2 had a key role in increasing the photoactivity of TiO2 [2, 3]. The better performance of Au and Ag on TiO2-CeO2 systems under UV irradiation were ascribed to more efficient interfacial charge transfer in the presence of metal nanoparticles (NPs), whereas the high activity under Vis irradiation was attributed to surface plasmon resonance (SPR) effects. The photo-excited electrons of the Au or Ag surface plasmon can be injected to the TiO2 conduction band, boosting the electrons-holes separation and then increasing their lifetime. Au (or Ag) NPs also favor the electron transfer from the TiO2 surface to the adsorbed molecular oxygen. The second strategy consisted in causing structural changes on the surface and the bulk of TiO2 through laser irradiation, an easy and green method to obtain reduced black TiO2, reported to be highly photoactive [4]. In this case the great increase of water splitting activity, observed under UV light, was related to the presence of Ti3+defects and oxygen vacancies in the TiO2 structure. The third approach was based on the combination of a template strategy to obtain TiO2 with a macroporous inverse opal structure, leading to slow photon effects with high light absorption, and chemical modifications achieved by the addition of host components as BiVO4, CeO2 or CuO, acting as photosensitizers, or doping agents as N, W or Hf, introducing defects. This mixed approach strongly enhanced the TiO2 photoactivity mainly under solar light irradiation. Finally, considering that TiO2, when used as powder in the liquid phase, cannot be easily recovered and reused, we investigated the possibility to immobilize it in polymethylmethacrilate (PMMA) matrices which are UV transparent, durable and low cost [5]. An improved photoactivity was in this case observed mainly when very thin PMMA/TiO2 films were used. References

1. Fujishima, A., Honda, K. Nature 1972, 238, 37-38. 2. Fiorenza, R., Bellardita, M., D’Urso, L., Compagnini, G., Palmisano, L., Scirè, S. Catalysts 2016, 6, 121. 3. Fiorenza, R., Bellardita, M., Palmisano, L., Scirè, S. J. Mol. Catal. A: Chem. 2016, 415, 56-64. 4. Filice, S., Compagnini, G., Fiorenza, R., Scirè, S., D’Urso, L., Fragalà, M. E., Russo, P., Fazio, E., Scalese. S. J.

Colloid Interface Sci. 2017, 489, 131-137. 5. Klaysri, R., Preechawan V., Thammachai N., Praserthdam P., Mekasuwandumrong O. Mat. Chem. & Phys.

2018, 211, 420-427.

O24AM


Inducing defects in gel-derived ZrO2 for visible light absorption

C. Imparatoa, A. Aronnea, G. D’Erricob, M. Fantauzzic, C. Passiud, C. Riccae, U. Aschauere, L. De Stefanof, I. Reaf, A. Rossicd

aDipartimento di Ing. Chimica, dei Materiali e della Prod. Industriale, Università di Napoli Federico II, Napoli, Italy. bDipartimento di Scienze Chimiche, Università di Napoli Federico II, Napoli, Italy.

cDipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Cagliari, Italy. dDepartment of Materials, ETH Zurich, Zurich, Switzerland.

eDepartement für Chemie und Biochemie, Universität Bern, Bern, Switzerland. fIstituto per la Microelettronica e Microsistemi, Consiglio Nazionale delle Ricerche, Napoli, Italy.


Zirconium oxide (ZrO2) has relevant applications as catalyst or support, either pure or mixed with other metal oxides. Despite the large band gap energy (> 5 eV), which limits its light absorption to the UV range, ZrO2 is gaining interest also for its photocatalytic properties. Its functional properties are largely influenced by structural defects: intrinsic defects are related to the non-stoichiometry deriving from the synthesis method and treatments employed, while extrinsic defects can be created by doping, introduction of organic molecules, etc. Oxygen vacancies are the main intrinsic defect in ZrO2, with a key role in defining ionic conductivity, surface reactivity, luminescence, and in the stabilization of the metastable tetragonal polymorph. They were recently proposed also as the origin of ferromagnetism and enhanced photocatalytic activity1,2. Therefore, understanding the formation and effects of vacancies and other types of defects would allow the design of oxide structures with tailored specific properties. Here we present a deep investigation of a series of ZrO2-based materials synthesized by a simple sol-gel procedure with the introduction of small organic molecules forming hybrid xerogels3. Thermal treatment in different conditions (temperature, gas atmosphere) induces the removal of the organic component and a remarkable coloration, related to nature and amount of generated defects. Complementary spectroscopic techniques are used for the characterization of the chemical and electronic structure of the materials: FTIR, diffuse reflectance UV-visible, X-ray photoelectron (XPS), electron paramagnetic resonance (EPR), steady state and time-resolved photoluminescence (PL). The samples annealed at 400 °C present tetragonal crystalline phase and a substoichiometric composition (ZrO2-x): selecting more oxidative or reducing treatment conditions differently charged oxygen vacancies could be observed. Theoretical DFT calculations on the formation energy and stability of different oxygen vacancies on tetragonal ZrO2 have also been performed, showing a good coherence with the experimental data. The ZrO2 xerogels exhibit an extended radiation absorption into the visible range, correlated to new energy levels formed in the band gap. The capability to efficiently separate photoexcited electron/hole pairs to induce redox reactions will be evaluated in view of the application of ZrO2 in photocatalytic processes, for instance for pollutants degradation or hydrogen production. A comparison can be made with a similar study led on TiO2, the most investigated photocatalytic semiconductor, where a significant reduction to Ti3+ was found as a consequence of the xerogel annealing, with effects on the material photoresponsivity4. References

1. S. Kumar, A. K. Ojha, J. Alloys Comp. 2015, 644, 654–662. 2. A. Rahman, S. Rout, J. P. Thomas, D. McGillivray, K. T. Leung, J. Am. Chem. Soc. 2016, 138, 11896-11906. 3. A. B. Muñoz-García, F. Sannino, G. Vitiello, D. Pirozzi, L. Minieri, A. Aronne, P. Pernice, M. Pavone, G.

D’Errico, ACS Appl. Mater. Interfaces 2015, 7, 21662-21667. 4. A. Aronne, M. Fantauzzi, C. Imparato, D. Atzei, L. De Stefano, G. D'Errico, F. Sannino, I. Rea, D. Pirozzi, B.

Elsener, P. Pernice, A. Rossi, RSC Adv. 2017, 7, 2373-2381.

O25AM


Alkyl carbonates as non-toxic reagents for selective gas-phase alkylation of phenolics

J. De Marona, T. Tabanellia, L. Ganzerlaa, C. Lucarellib, F. Cavania

a Dipartimento di Chimica Industriale “Toso Montanari”, Alma Mater Studiorum Università di Bologna, Viale del Risorgimento 4, Bologna, Italia

b Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, Como, Italia e-mail: [email protected]

Alkyl carbonates are biodegradable and non-toxic compounds widely employed as aprotic polar solvents; moreover, they are industrially produced valorizing renewable carbon feedstocks (CO2)1 and are useful building blocks in organic synthesis due to their adjustable reactivity varying reaction temperature, co-reactant nature and catalyst properties. For these reasons, they represent a sustainable and safer alternative to hazardous reagents such as methyl iodide, dimethyl sulfate and phosgene2. When used as alkylating agents of phenolics (softer nucleophiles compared to aliphatic substrates), organic carbonates reactivity over basic catalysts is far higher than that of parent alcohols, with a chemo-selectivity strongly directed towards oxygen-alkylation3. This behavior was confirmed by reacting phenol with diethyl carbonate (DEC) over a basic magnesium oxide obtaining complete conversion of the aromatic substrate and ethyl phenyl ether (EPE) with 70% selectivity at relatively low temperature (350°C). In order to expand the versatility of this approach, the present research focused on the development of bifunctional Mg/Al/O catalyst (possessing both acidic and basic properties). This way, phenol ethylation was investigated in a continuously fed gas-phase reactor.

The obtained results show that at low temperature (≤300°C) only basic sites are active, leading, over the Mg/Al/O mixed oxide, to an EPE selectivity similar to the one observed with MgO. However, at higher reaction temperatures, acidic sites (Al3+O2-) can catalyse the transposition/disproportion of the alkyl phenyl ethers previously produced by phenols O-ethylation over basic Mg2+O2- sites. This cascade effect allowed us to shift the overall chemo-selectivity from O-alkylated to C-alkylated products and the overall regio-selectivity towards ortho-isomers, even if a minor contribute of direct C-alkylation cannot be excluded. Therefore, the modulation of catalyst surface properties (obtained replacing part of Mg2+ with Al3+ ions) and reaction temperature, represents a promising approach for the synthesis of both C- and O-alkylated phenolics using alkyl carbonates as highly reactive and safe reagents. References

1. Honda, M. ChemSusChem. 2013, 6, 1341-1344. 2. Aricò, F. Russ. Chem. Rev. 2010, 79, 479-489. 3. Selva, M. Green Chem. 2008, 10, 457-464.

O26AM


A step-by-step approach to heterogeneous catalysts for olefin conversion

A. Piovano University of Torino, Department of Chemistry, NIS Centre and INSTM, via Quarello 15A, 10135 Torino, Italy


Synthetic polymers are nowadays one of the main features of the continuously evolving society. Among all these materials, polyolefins count for more than 60% of the World polymer demand.1 Their widespread commercial relevance started in the early 1950s, after the discovery of Ziegler-Natta and Phillips catalysts, which allowed the large scale production in mild condition and with a good control of the thermal and structural properties of the products. Successive breakthroughs modified these heterogeneous catalysts improving their activity, making the processes more efficient and enhancing the selectivity to specific products.2 However, despite more than sixty years of industrial practice, all the advances in the catalysis have been based so far on a trial and error approach, by serially screening the activity of differently composed catalyst.3 Some fundamental questions are still open about the structural and electronic properties of the active sites on the catalysts and their functioning during the olefins reaction. Answering these questions can disclose the way for a real rational design of the catalysts, to selectively produce in the most efficient way the most suitable materials for any specific application. In such a context, this thesis project pointed out the potentiality of a step-by-step approach, characterizing through a physico-chemical analysis all the intermediate stages upon the formation of the catalysts and their operational test. In particular, the characterization took advantage of several spectroscopic techniques, giving information about the coordination and oxidation state of the metal centers, the functional groups at the surface of the catalysts, and the mutual interactions among all the components.4 Such an investigation required the development of dedicated experimental setups, allowing the performance of the spectroscopic measurements under realistic reaction conditions, for a direct comparison with the industrial systems.5

References 1. Market Report: Global Catalyst Market; 3rd ed.; Acmite Market Intelligence: Ratingen, Germany, 2015. 2. Nowlin, T. E. Business and Technology of the Global Polyethylene Industry; Wiley-Scrivener: New York, 2014. 3. Busico, V.; Cipullo, R.; Mingione, A.; Rongo, L. Ind. Eng. Chem. Res. 2016, 55, 2686-2695. 4. Groppo, E.; Seenivasan, K.; Barzan, C. Catal. Sci. Technol. 2013, 3, 858-878. 5. Bañares, M. A. Catal. Today 2005, 100, 71-77. Acknowledgements: The thesis work was carried out under the supervision of Professor Elena Groppo. Besides, it took advantage from the contribution of several co-workers, in particular I am sincerely grateful to Giorgia A. Martino and Caterina Barzan, and to Professors Silvia Bordiga, Mario Chiesa and Adriano Zecchina.

PM5


Modern methods of synthesis for innovative materials obtained

from renewable resources: Synthesis of biopolyurethanes

A. G. Laurenzaa, V. Pantone b, C. Annesea, F. Fracassia, C. Fuscoc, A. Russob, L. D’Accoltia aDipartimento di Chimica, Università di Bari Aldo Moro, Bari, Italy.

bGreenswitch S.r.l., Ferrandina, Italy. cICCOM-CNR, Bari, Italy.


Bio-polyols synthesized from vegetables oils are a great alternative to petrochemical polyols for polyurethanes industry. [1] The simplest approach to bio-polyols synthesis involves epoxidation of carbon–carbon double bond of unsaturated fatty ester moieties and subsequent epoxide ring-opening by nucleophilic reagents. In order to improve the latter process by increasing both productivity and product quality, the advantages of flow chemistry were exploited, such as facile automation, reproducibility and improved safety, investigating for the first time in the literature the methanolysis reaction of epoxidized soybean oil (ESBO) (Fig. 1a) in a continuous flow mode using the Vapourtec R-series reactor (Fig. 1b).

Fig. 1. (a) Metanolysis reaction of ESBO in continuous flow mode (b) Vapourtec R-series reactor.

Compared with batch reaction, flow mode allowed the cut of the reaction time from 30 min to 2 min, and the reduction of catalyst concentration by an order of magnitude, which brought significant benefits in terms of cost efficiency and eco-sustainability, rendering the method suitable for industrial applications. [2] Subsequently, the bio-polyol was used for the realization of a bio-polyurethane (Fig. 2a) to be used for the first time in the Digital Doming technique (Fig. 2b). Bio-resins produced can favorably compete with the analogous fossil polymers, giving high-quality surface coatings. [3]

Fig. 2. (a) Bio-based polyurethane synthesis, (b) Representation of the Digital Doming technique and its effect.

References 1. S. Petrovic, Z. S Polym Rev. 2008, 48, 109-155. 2. Pantone, V., Laurenza, A. G., Annese, C., Fracassi, F., Fusco, C., Nacci, A., Russo, A., D’Accolti, L. Ind Crops

Prod. 2017, 109, 1-7. 3. Pantone, V., Laurenza, A. G., Annese, C., Comparelli, R., Fracassi, F., Fini, P., Nacci, A., Russo, A., Fusco, C.,

D’Accolti, L. Materials 2017, 10, 848. Acknowledgements: This work was supported by “PIANI di SVILUPPO INDUSTRIALI attraverso PACCHETTI INTEGRATI di AGEVOLAZIONE (PIA) Regione Basilicata codice progetto 227179”.

a) b)

a) b)

PM6


Preparation and Characterization of Zinc Oxide Photoanodes for Water-Based Dye-Sensitized Solar Cells

E. Marucciaa, F. Bellaa, S. Gallianob, V. Caudac, C. Barolob, C. Gerbaldia

aGAME Lab, CHENERGY Group, Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.

bDepartment of Chemistry and NIS Interdepartmental Centre, Università degli Studi di Torino, Via Giuria 7, 10125 Torino, Italy.

cTrojan Nano Horse Laboratory (ERC), MPMNT Group, Department of Applied Science and Technology – DISAT, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.

[email protected] This work focuses on the preparation and characterization of zinc oxide based photoanodes conceived for application in water-based dye-sensitized solar cells (DSSCs). The results achieved, combined with the use of biosourced electrolyte components, open up a variety of very interesting features in the scenario of sustainable, low-cost and easy processable aqueous DSSCs. Nowadays, one of the main challenges in the field of DSSCs is to replace the commonly used organic electrolyte solvents, which are highly volatile, flammable, toxic and sensitive to moisture/water contaminations with water, the universal, greenest and cheapest solvent 1. In this work, water was used as the unique solvent to dissolve the redox couples in the electrolyte system; moreover, in order to improve the long-term stability of devices, a biosourced jellifying agent was added, namely carboxymethylcellulose. In the framework of photoanode development, the most commonly used titanium dioxide was replaced by zinc oxide (ZnO). ZnO has similar semiconducting characteristics and some additional advantages, such as enhanced electron mobility and a variety of possible nanostructures with peculiar morphological characteristics, which can be exploited to tailor the photoanode architecture. In particular, three different microstructures (i.e., desert roses, multipods and microwires) were obtained through hydrothermal synthesis in order to maximize, at the same time, the surface area of the semiconducting layer and the electron transfer rate 2. This target was reached with the desert rose morphology that, among others, was confirmed as the most suitable photoanode also by photovoltaic measurements. At the same time, in order to tailor as desired the photoanode architecture, the ZnO dissolution caused by prolonged contact with the acidic groups present in the electrolyte/dye solution was taken into account. Indeed, the optimization of the sensitizing conditions, i.e. immersion time of the electrode and co-adsorbent concentration (chenodeoxycholic acid, CDCA) in the dye solution, was carried out through a chemometric approach in order to limit/overcome this issue. This method allowed to identify the optimal manufacturing conditions in 1 h of sensitizing time and in a molar ratio of 1:50 between dye and CDCA concentrations, through which an efficiency of 0.34% was achieved (Figure 1).

Figure 1 J‐V curve of lab‐scale DSSC with ZnO photoanode sensitized under optimized conditions. Inset: FESEM micrograph illustrating the peculiar desert rose morphology of ZnO.

References

1. Bella F., Gerbaldi C., Barolo C., Grätzel M., Chem. Soc. Rev. 2015, 44, 3431-3473. 2. Cauda V., Stassi S., Lamberti A., Morello M., Pirri C. F., Canavese G., Nano Energy. 2015, 18, 212-221.

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Soot Oxidation Activity of a Core/Shell CeZrO2/C Mixture with Improved Interfacial Contact

E. Aneggi,a,* L. Soler,b J. Llorca,b P. Vernouxc, M. Aouinec, Trovarellia

aUniversità degli Studi di Udine, Udine, Italy

bUniversitat Politècnica de Catalunya, Barcelona, Spain c Univ. Lyon, Université Claude Bernard Lyon 1, CNRS – IRCELYON – UMR 5256, Villeurbanne, France


Ceria-based materials, and particularly CeO2-ZrO2 (CZ) solid solutions, have a great soot oxidation potential and over the last years a large number of studies have investigated the behavior and the role of CeO2 in this complex reaction environment. This mechanism deeply relies on the degree of contact between CeO2 and carbon. Therefore, it is of great importance to investigate the morphology of catalyst and carbon contact at nanoscale, to highlight the promotion of soot oxidation in the interfacial region1. In this study the effect of different atmosphere and diverse contact conditions on soot combustion over CeO2-ZrO2 based catalyst has been investigated to better understand the oxygen transfer ability of ceria-zirconia at low temperatures. The difference in the contact morphology between carbon soot and CZ particles is shown to strongly affect soot oxidation activity; in particular, increasing the carbon-ceria interfacial area, the oxidation temperature significantly decreases. In addition, with a higher degree of contact, the reaction is less affected by the presence of NOx: while in loose contact mode the use of NOx+O2 mixture contributes to lower soot oxidation temperature by several degrees, no promotion is observed in samples where soot/catalyst contact is improved. Specifically, when the interfacial ceria-zirconia/soot interaction is strongly enhanced through the formation of a core/shell like structure, gas phase O2 promote the formation of active oxygens through oxygen vacancies located at the interface2, resulting in a more powerful oxidant than NO2. This has been also observed by in situ environmental transmission electron microscopy which evidences that improving carbon soot/CZ contact the carbon particles are oxidized in the presence of oxygen and the electron beam already at room temperature (Figure 1). The NO oxidation over CZ in the presence of soot has also been analyzed. The existence of a core/shell structure strongly enhances reactivity of interfacial oxygen species while affecting negatively NO oxidation characteristics. The active oxygen species formed through interaction of gas-phase oxygen with interfacial ceria vacancies immediately react with soot enhancing the combustion at very low temperature and hindering NO oxidation that usually takes place in that temperature range (Figure 2). These findings are significant in the understanding of redox chemistry of ceria and help determining the role of active oxygen species in soot oxidation.

References

1. Aneggi E. et al., Angew. Chem. Int. Ed. 2015, 54, 14040–14043. 2. Soler L. et al., ChemCatChem 2016, 8, 2748-2751

Figure 1: ETEM images extracted from a video recorded under 0.37 mbar of O2 at room temperature on a sample with improved soot/CZ contact. Beam voltage: 300 kV; a) starting time t0, b) t0 +5s, c) t0 + 10s, d) t0 + 15s, e) t0 + 20s and f) t0 + 25s.

Figure 2: Temperature programmed oxidation profiles of NO2 evolved from CZ/C mixtures at different contact condition under NO+O2 gas flow: loose contact (blue), tight contact (green), improved core/shell contact (red).

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A PGM-free NOx Adsorber + Selective Catalytic Reduction system (AdSCR) for the control of cold start NOx emissions

F. Gramignia, T. Selleria, I. Novaa, E. Tronconia

a Politecnico di Milano, Milano, Italy e-mail: [email protected]

Most of NOx emissions from Diesel engines occur during the cold-start period due to poor activity of SCR converters and to the urea injection temperature threshold1. Starting from previous fundamental investigations2,3, this work presents a novel concept of multifunctional catalytic device suitable to capture and store NOx at room temperature and to reduce them with NH3 at higher temperatures (AdSCR = Adsorption + Selective Catalytic Reduction)4. The strategy of the AdSCR system is to add a storage functionality to a state-of-the-art SCR catalyst, enabling both capture of NOx at room temperature and direct reduction of the stored NOx at higher temperatures in a single device. It is free of PGM materials and does not require lean-rich cycling, being operated just like a SCR catalyst. Thus, it can replace conventional SCR converters, leading to improved DeNOx efficiencies without modifications of the aftertreatment chain. An experimental study was performed over different combinations (physical mixtures) of two SCR catalysts (Fe-ZSM-5 and Cu-CHA) and two NOx storage materials (BaO/Al2O3 and CeO2/Al2O3). Cold start mimicking experiments were performed to analyze the overall DeNOx performances under realistic conditions: NO (300 ppm) and CO2 (8% if present) were cofed at r.t. followed by a T-ramp (15 °C/min). In some experiments, H2O (8%) was added to the feed stream after 100 s, mimicking the H2O delay observed in real systems at engine startup. When the temperature reached 170 °C (here regarded as a T-threshold for urea injection), NH3 (800 ppm) was fed to the reactor to start the SCR reactions. Our results show that the AdSCR system can adsorb NO in O2 during the cold-start period. In particular, in cold-start mimicking runs in absence of water and CO2 the best performance were obtained over Cu-CHA + BaO/Al2O3: (1) after the NO (300 ppm) step feed, the NO outlet concentration exhibited a long dead time (420 s) before NOx breakthrough; (2) the overall engine-out NOx were reduced by 93% before NH3 (800 ppm) injection; (3) as soon as NH3 was fed, a peak of N2 (850 ppm) was released and the NO concentration started to decrease due to the onset of the Standard SCR reaction. Additional data show also that the effects of water and CO2 are detrimental for the AdSCR performances, but can be counteracted by a careful optimization of the ratio between the SCR component and the NOx storage material, and by selecting NOx storage materials more tolerant to CO2 (such as CeO2). These promising results may warrant further studies aimed at developing and optimizing new aftertreatment systems based on the AdSCR concept. References

1. Lee, J., Ryou, Y., Cho, S.J., Lee, H., Kim, C.H., Appl. Catal. B, 2018, 226,71–82 2. Ruggeri, M.P., Selleri, T., Colombo, M., Nova, I., Tronconi, E., J. Catal., 2014, 311, 266–270 3. Selleri, T., Ruggeri, M.P, Nova, I., Tronconi, E., Topics in Catalysis, 2016, 59, 678–685 4. Selleri, T., Gramigni, F., Nova, I., Tronconi, E, Dieterich, S., Weibel, M., Schmeisser, V., Catal. Sci. Tecnol., 2018,

8, 2467-2476

Acknowledgements:We thank S. Dieterich, M. Weibel, V. Schmeisser (all Daimler A.G.) for the support

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NH3-SCR reaction for NOx removal over Cu- and Fe-exchanged hydroxyapatite catalysts

S. Campisia, M.G. Gallonia, A. Gervasinia, T. Delplancheb aUniversità degli Studi di Milano, Dipartimento di Chimica, Via C. Golgi, 19 – 20133 Milano, Italy.

bSolvay, Soda Ash & Derivatives, rue de Ransbeek 310, 1120 Brussels, Belgium. e-mail: [email protected]

Nitrogen oxides (NOx) are known to have a harmful impact on the environment and human health. Selective catalytic reduction with NH3 as the reducing agent (NH3-SCR) is the most valuable technology for NOx emissions abatement1,2. In view of ever more stringent regulations for the emission of NOx, besides the optimization of well-known catalysts (i.e., Cu and Fe zeolites), the development of new catalysts represents an unavoidable challenge. Hydroxyapatites (HAPs, Ca10-

x(PO4)6-x(HPO4)x(OH)2-x, with 0<x<1) are a class of natural minerals, which, similarly to zeolites, are able to accommodate metal ions without altering their own structural and morphological properties. In this work, we explored the potentiality of metal functionalized HAP as novel catalysts for NH3-SCR reaction3. In particular, we investigated the introduction of Cu or Fe on the HAP

framework in different amount (metal loading: 1.5 < wt.% < 12), from different salt precursors and by different preparation methods (ion exchange and wet impregnation). The catalytic performances of the functionalized hydroxyapatite materials have been evaluated in NH3-SCR tests carried out in a wide temperature interval (120-500°C) with different NH3/NO ratios and at fixed contact time. XRPD, Uv-vis-DRS, EPR, and Mössbauer analyses provided fundamental details on the metal (Cu or Fe) sitting on HAP surface. As a general

trend, Cu/HAP samples resulted more active than Fe-based ones, which worked at higher temperature (Figure). It was found that an optimum Cu-concentration on HAP of ca. 6 Cu wt.% could be associated with the best active and selective SCR catalysts, independent of the used Cu-deposition method. This behaviour indicated that, likely, there is a critical dimension of the formed Cu-species for the obtainment of high activity in the NH3-SCR reaction. References

1. Moliner, M., Martínez, C., Corma, A. Chem. Mater. 2014, 26, 246-258. 2. Schiavoni, M., Campisi, S., Gervasini, A. Appl. Catal. A 2017, 543, 162-172. 3. Delplanche, T., Gervasini, A. U.S. Provisional Patent Application with U.S. Serial N°. 62/431406 and N°.

62/431407, 2016. Acknowledgements: This work was funded by Solvay, Soda Ash & Derivatives, Bruxelles

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Catalytic and photocatalytic processes for the production of alternative fuels and chemicals from renewable sources

M. Compagnonia, I. Rossettia

a Dip. Chimica, Università degli Studi di Milano, via C. Golgi 19, 20133 Milan, Italy

This work presents the PhD research project of Matteo Compagnoni. In particular, the presentation focuses on the valorization of bioethanol through the heterogeneously catalysed production of H2 and ethylene. The whole thesis was based on innovative heterogeneous catalytic processes, addressed from an industrial chemistry point of view. Besides the screening of different catalyst formulations, the attention was predominantly focused on process design, including the optimisation of process conditions, the use of less purified (less expensive) raw materials, less demanding conditions, etc. A preliminary economic assessment was also carried out for the centralised production of hydrogen from diluted bioethanol.

References

1. Rossetti, I. et al. Chem. Eng. J. 2015, 281, 1036–1044. 2. Compagnoni, M. et al. Catal. Sci. Technol. 2016, 6, 6247–6256. 3. Compagnoni, M. et al. Appl. Catal. B Environ. 2017, 203, 899–909 4. Rossetti, I. et al. Appl. Catal. B Environ. 2017, 210, 407–420. 5. Compagnoni, M. et al. Energy & Fuels 2017, 31, 12988–12996.

Acknowledgements: This work was funded by Università degli Studi di Milano

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The chemical-loop reforming of bio-ethanol for H2 production O. Vozniuk1,2,3, S. Albonetti1, F. Cavani1, N. Tanchoux2, F. Quignard2, F. Di Renzo2, J.M.M.

Millet3 1Dipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna, Viale Risorgimento 4, 40136 Bologna,

Italy 2Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, ENSCM, 8 Rue Ecole Normale, 34296 Montpellier

Cedex 5, France 3IRCELYON, UMR5256 CNRS- Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne, France

e-mail: [email protected] Hydrogen production is presently based on the reforming of natural gas or naphtha. Less energy intensive and more sustainable processes for H2 production are appealing for both industry and consumer applications. A highly attractive route is steam reforming of bio-alcohols, in principle CO2 neutral. Costly separation processes can be avoided by splitting the process into two alternated steps (chemical-loop reforming), in the aim of achieving two separate streams of H2 and COx.

The principle of the thermochemical-loop cycle is that an oxygen-storage material is first reduced by an ethanol stream, and then re-oxidized by water, in order to produce H2 and restore the original oxidation state of the looping-material. In this work, we report about the reactivity of spinel ferrites in the production of H2 from ethanol by chemical-loop reforming.1,2 The following spinel ferrites were prepared by co-precipitation and used as electrons/O2- vectors: MFe2O4 (CoFe2O4, NiFe2O4, CuFe2O4)1 M1

0.6-xM2xFe2.4Oy, (Co0.6Fe2.4Oy, Mn0.6Fe2.4Oy,

Mn0.3Co0.3Fe2.4Oy, Cu0.3Mn0.3Fe2.4Oy and Cu0.6Fe2.4Oy).2 Redox properties and catalytic activity to generate H2 by oxidation with steam obtained with the materials are reported. In addition, the research includes in-situ DRIFTS and in-situ XPS studies that allowed gaining information at

molecular level and following surface changes within the reduction/oxidation process during the chemical loop. Bulk characterizations performed using XRD and Raman/Mössbauer spectroscopy showed that substitution of Fe cations by other transition metals leads to the formation of inverse, normal, or mixed spinels with different degree of inversion. Besides this, introduction of a foreign M-cation into magnetite (Fe3O4) structure appeared to modify the redox properties and alter cycling stability of the ferrospinel.

Co-, Ni- and Cu-incorporation effectively improves decomposition/oxidation of ethanol; however a greater amount of coke is accumulated leading to COx generation during the re-oxidation step with water. Addition of Mn(II) into the system helps to significantly reduce the amount of coke and hence avoids a fast deactivation of the material. Therefore, changing the catalyst composition and thus tuning its redox properties in order to optimize the ratio between the degree of reduction and the amount of coke deposition, allowed decreasing the amount of COx generated by oxidation with water steam, which is an important issue to produce clean H2. References 1. Ochoa, J.V.; Trevisanut, C.; Millet, J.-M. M.; Busca, G.; Cavani, F., J. Phys. Chem. C., 2013, 117 (45), 23908–23918. 2. Vozniuk, O.; Agnoli, S.; Artiglia, L.; Vassoi, A.; Tanchoux, N.; Di Renzo, F.; Granozzi, G. and Cavani, F., Green Chem., 2016, 18, 1038–1050.

Acknowledgements: This work was co-funded through a SINCHEM Grant. SINCHEM is a Joint Doctorate program selected under the Erasmus Mundus Action 1 Program (FPA 2013-0037).

Figure 1 : TEM image of cycled Co0.3Mn0.3Fe2.4Oy

Figure 2: Integrated values of H2 produced during re-oxidation with H2O

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Hydrogen production via steam reforming of methanol over a Cu/ZrO2 catalyst: Effect of Si addition

F. Bossolaa, N. Scottia, C. Evangelistia, V. Dal Santoa

aInstitute of Science and Molecular Technology – CNR, Via Golgi 19, Milan, Italy. e-mail: [email protected]

Methanol steam reforming (MSR) is a promising process for the on-board H2 production in fuel cell-powered vehicles. Low CO levels and cheap catalysts as free as possible of rare metals are required. Cu/ZrO2 catalysts have been extensively studied at this purpose, finding that the support–and the preparation protocol–greatly affects the final catalytic performances1-2. In fact, the presence of tetragonal phase of zirconia appears to be much more beneficial to the reaction compared the monoclinic or amorphous phases3. Unfortunately, in order to stabilize such phase, high calcination temperatures or the addition of exotic elements, such as yttrium, are necessary at expenses of the surface area. Silica can be used instead as it is reported to increase the surface area of zirconia, but Cu/SiO2 catalysts have demonstrated poor activity in MSR, hence silica segregation must be avoided1, 4. In this work, silica was used as cheap doping agent in zirconia rather than as support. A sol-gel procedure was used, and catalysts with different amounts of silica were studied. The reactivity tests were performed at 260 °C by feeding a methanol/water solution (steam-to-carbon ratio of 1.3) at a GHSV of 3500 h-1. The results show that relatively low levels of silica (max 10 wt.%) are extremely beneficial to the catalytic activity, whereas higher levels are detrimental. The H2 productivity of the catalyst with the 10 wt.% of silica is the highest compared to other Cu-based catalysts reported in the open literature at similar working conditions, and no CO was detected2. The improved surface area of these catalysts, evaluated by the BET method, clearly plays a crucial role in boosting the H2 productivity, but that is not enough to explain the promoting effect of silica. In fact, the difference in surface area between the Cu/ZrO2 and the Cu/ZrO2-SiO2 catalysts is not sufficient to account for the improved H2 productivity. H2-TPR experiments, however, indicate that the addition of silica into the zirconia matrix hinders the formation of the monoclinic zirconia since the peak ascribable to Cu deposited on this phase disappears with the addition of silica. Preliminary HRTEM investigations support these findings evidencing that in the Cu/ZrO2-SiO2 catalysts Cu is homogeneously dispersed on crystalline zirconia, with no silica segregation observed. These results highlight that no expensive dopants are required to achieve high H2 production from methanol, but rather a fine control of the crystalline phases of the zirconia support by using the proper synthesis protocol. X-ray based analyses and FITR studies with probe molecules will be performed to definitely elucidate the promoting role of silica in the Cu/ZrO2-SiO2 catalyst and to better characterize the Cu phase. References

1. Yong, S. T.; Ooi, C. W.; Chai, S. P., Wu, X. S. Int. J. Hydrogen Energ. 2013, 38, 9541-9552. 2. Davidson, S. D.; Zhang, H.; Sun, J., Wang, Y. Dalton Trans. 2014, 43, 11782-802. 3. Samson, K.; Śliwa, M.; Socha, R. P., Góra-Marek, K.; Mucha, D.; Rutkowska-Zbik, D.; Paul, J. F.; Ruggiero-

Mikołajczyk, M.; Grabowski, R.; Słoczyński, J.ACS Catal. 2014, 4, 3730-3741. 4. Zhao, Q.; Shih, W. H.; Chang, H. L., Andersen, P. Appl. Catal. A: Gen. 2004, 262, 215-221.

Acknowledgements: This work was funded by EIT Raw Materials through project FREECATS (Project no. 15054).

Figure 1. MSR activity on Cu/ZrO2 and Cu/ZrO2-SiO2.

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A DoE approach to the formulation of aqueous-based electrolytes for Dye-Sensitized Solar Cells

S. Gallianoa, F. Bellab, F. Giordanoc, G. Boshoolood, A. Hagfeldtc, M. Graetzelc, G. Viscardia,

C. Gerbaldib, C. Baroloa

aDepartment of Chemistry, NIS Interdepartmental Centre and INSTM Reference Centre, Università degli Studi di Torino, Torino, Italy

bGAME Lab, Department of Applied Science and Technology (DISAT), Politecnico di Torino, Torino, Italy cInstitute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland

dDepartment of Chemistry Ångström Laboratory, Uppsala University, Uppsala, Sweden e-mail: [email protected]

In the last five years, Dye-Sensitized Solar Cells (DSSCs) based on aqueous electrolytes have attracted a lot of attention, being considered as one of the possible breakthroughs towards sustainable DSSCs.1 If opportunely developed and optimized, aqueous solar cells can be truly considered a step forward to zero-impact photovoltaic device.2-3 Moreover, the possibility of gellyfing the electrolyte into a solid matrix can reduce the leakage outside the device, thus increasing the long-term stability. In this respect, bio-derived polymers (i.e. carboxymethyl cellulose, xanthan gum, alginate derivatives…) appear promising candidates for electrolyte stabilization, being renewable and easy available at low cost.4 In this contribution the use of a chemometric Experimental Design approach (DoE) in the optimization of lab-scale DSSCs will be discussed. DoE was applied to investigate the relationships between the relevant experimental parameters concerning the formulation of iodine and cobalt-based 100% aqueous electrolytes and the electrochemical and photovoltaic parameters of the resulting devices. Thanks to the statistically optimized preparation conditions and engineered formulations we were able to obtain reproducible and stable lab-scale devices based on liquid5 and gelled aqueous electrolytes. References

1. Bella, F.; Gerbaldi, C.; Barolo, C.; Grätzel, M. Chem. Soc. Rev. 2015, 44, 3431-3473. 2. Bella, F.; Galliano, S.; Falco, M.; Viscardi, G.; Barolo, C.; Grätzel, M.; Gerbaldi, C. Chem. Sci. 2016, 7, 4880-

4890. 3. Galliano, S.; Bella, Gerbaldi, C.; Falco, M.; Viscardi, G.; Grätzel, M.; Barolo, C. Energy Technology 2017, 5,

300-311. 4. Bella, F.; Galliano, S.; Falco, M.; Viscardi, G.; Barolo, C.; Grätzel, M.; Gerbaldi, C. Green Chem. 2017, 19, 1043-

1051. 5. Galliano, S.; Bella, F.; Piana, G.; Giacona, G.; Viscardi, G.; Gerbaldi, C.; Grätzel, M.; Barolo, C. Sol. Energy

2018, 163, 251-255.

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Structural and Electrochemical Characterization of NdBa1-xCo2-yFeyO5+δ as Cathode for Intermediate Temperature SOFCs

G. Cordaroa, A. Donazzib, R. Pelosatoa, c, I. Natali Sorac, C. Cristiania, G. Dotellia

aPolitecnico di Milano, Dip. di Chimica, Materiali e Ingegneria Chimica, P.zza Leonardo da Vinci 32, Milano, Italy bPolitecnico di Milano, Dip. di Energia, Via Lambruschini 4, Milano, Italy

cINSTM R.U. e Università di Bergamo, Dip. di Ingegneria e Scienze Applicate, Viale Marconi 5, Dalmine, BG, Italy e-mail: [email protected]

Cobalt-based layered perovskites are promising compounds for application as cathodes in IT-SOFCs, thanks to their mixed ionic and electronic conductive behavior and high catalytic efficiency in the Oxygen Reduction Reaction (ORR) [1, 2]. In this work, the effects of Fe doping and Ba deficiency are investigated by production and characterization of the series NdBa1-xCo2-yFeyO5+δ (NBCF), with x = 0, 0.1 and y = 0, 0.1, 0.2, 0.3, 0.4. The materials are synthesized via the molten citrate technique, and their physicochemical properties are characterized by XRD, TG-DTA, SEM, TPO and cerimetric titration. The electrical conductivity is measured with a 4-point DC method, and Electrochemical Impedance Spectroscopy (EIS) experiments are performed to determine the ORR activity. In order to derive the main kinetic dependences and the consequences of Fe doping on the ORR activity, the results are quantitatively analyzed with the Equivalent Circuit Method (ECM) and with a multistep, physical model of the electrode. All the compounds have an A-site ordered perovskite structure. The Fe-free sample arranges in an orthorhombic crystal lattice, while the Fe-containing samples in a tetragonal cell. The oxygen content decreases due to Ba deficiency and increases due to Fe doping. The effect of Ba deficiency is more pronounced on samples with Fe doping and leads to the generation of a high concentration of oxygen vacancies. Fe doping reduces the conductivity, although even at the highest Fe amount (NBCF4) the conductivity (200 S/cm at 700°C) doubles the threshold value for applications (100 S/cm). The EIS tests show that Fe doping enhances the electrochemical activity but impairs the activity improvement due to Ba deficiency. The Area Specific Resistance (ASR) progressively reduces when increasing the Fe amount, i.e. passing from no doping (NBC) to NBCF4 (Fig. 1A). The opposite trend is found with Ba deficiency, and the best performance is reached at low Fe doping. For all the samples, the ECM analysis reveals that the surface electronation at the gas/electrode interface (middle frequency) and the oxygen ion transfer (high frequency) are the main ORR contributions. The physically-sound model (Fig. 1B) indicates the first electronation of the O adatom as the Rate Determining Step of the mechanism: the increase of Fe doping mainly affects the electronation step.

Figure 1. Logarithmic plot of ASR values versus the inverse of the temperature. A) Increasing Fe amount with no Ba

deficiency. B) Increasing Fe amount with 10% Ba deficiency (x = 0.1).

References: [1] Pelosato R. J. Power Sources 2015, 298, 46-67. [2] Donazzi A. Electrochim. Acta 2015, 182, 573-587.

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ANALYSIS AND KINETIC CONSEQUENCES OF CARBON FORMATION IN METHANE DRY REFORMING ON RHODIUM IN OPERANDO-RAMAN

ANNULAR REACTOR

G. Moronia, A. Donazzia, M. Maestria aLaboratory of Catalysis and Catalytic Processes, Dipartimento di Energia, Politecnico di Milano, via La Masa 34,

20156, Milano, Italy e-mail: [email protected]

In this study, we have performed a combined spectroscopic kinetic analysis of Methane Dry Reforming (MDR) reaction by using an operando-Raman annular reactor1. MDR on Rh/α-Al2O3 runs have been carried out in isothermal conditions (300-750°C) at different CO2/CH4 ratios in order to investigate the effect of the co-reactant concentration on the formation of carbon deposits at the catalyst surface. When CO2 is supplied in excess with respect to the stoichiometry of the reaction (CO2/CH4 > 1), no carbonaceous deposits have been detected. Instead, when an equimolar feed (CO2/CH4 = 1) is supplied to the reactor, the typical G and D peaks of graphitic and disordered carbonaceous species can be identified in the Raman spectra. This is accompanied by a concomitant decrease of the methane conversion. These operando-Raman kinetic tests have been interpreted via reaction path analysis using microkinetic modeling2-3. This analysis reveals that the catalytic mechanism consists of a series of dehydrogenations of the hydrocarbon until the formation of C-species at the surface of the catalyst. This dehydrogenation process is accompanied by a reduction pathway for CO2 which eventually forms OH species at the surface. Then OH oxidizes the carbonaceous species, leading to CO and H2. When the co-reagent is supplied in excess with respect to CH4, the CO2 activation is quasi-equilibrated and the solely kinetically relevant step is the CH4 dehydrogenation. Thus, the overall reaction rate is not influenced by CO2 concentration. At CO2/CH4 = 1, the CO2 activation pathway is no longer equilibrated. This introduces a kinetic dependence on the CO2 concentration of the reaction rate and in a reduction of the coverage of OH-species at the surface. As a result, this reduced concentration of OH-species is not able to efficiently remove the C-species, which then accumulate, as revealed by the appearance of the G and D peaks in the Raman spectra. This mechanistic interpretation is further confirmed by adding a small amount (0.1%) of O2 to the feed stream for CO2/CH4 = 1. In fact, the co-feeding of O2 in the system is able to provide an additional route at the surface for the formation of OH. As a result, C-species do not accumulate and G and D peaks are not detected in the Raman spectra. We also performed MDR experiments at fixed CO2/CH4 = 2 with different CH4 concentration (CO2/CH4 = 4/8, 8/16, 10/20, N2 to balance). By increasing the methane concentration, the experiments revealed a clear deactivation of the catalysts as consequence of accumulation of carbon on its surface, resulting in a progressive masking of the active sites. This interpretation was confirmed by the microkinetic analysis of the experiments. References

1. Maghsoumi, A.; Ravanelli, A.; Consonni, F.; Nanni, F.; Lucotti, A.; Tommasini, M.; Donazzi, A.; Maestri, M. React. Chem. Eng. 2017, 2, 908-918.

2. Maestri, M.; Vlachos, D.G.; Beretta, A.; Groppi, G.; Tronconi, E. J. Catal. 2008, 259, 211-222. 3. Maestri, M.; Livio, D.; Beretta, A.; Groppi, G. Ind. Eng. Chem. Res. 2014, 53 (27), 10914–10928

Acknowledgements: Financial support from the European Research Council (Grant 677423 – www.shape.polimi.it) is gratefully acknowledged.

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Kinetic aspects for Inulin hydrolysis

V. Russoa,b, A.P. Nebredab, H. Grénmanb,c, R. Turcoa, R. Vitielloa, R. Tessera, M. Di Serioa, T. Salmib

aUniversità degli Studi di Napoli Federico II, Chemical Sciences Department, Napoli, Italy. bÅbo Akademi University, Johan Gadolin Process Chemistry Centre, Turku/Åbo, Finland.

cÅbo Akademi University, Molecular process and materials technology, Turku/Åbo, Finland. e-mail: [email protected]

Fructose is widely used in alimentary industry due to its unique sweetness and its physical and functional properties. It is considered the sweetest sugar found in nature and when it is added to food and drinks it improves the flavor, color, palatability and product stability [1]. The conversion of inulin to fructose was investigated, deepening the kinetic and technological aspects dealing both with homogeneous and heterogeneous catalysis. The HCl-catalyzed hydrolysis was investigated in a laminar flow reactor, while SMOPEX-101 (heterogeneous ion-exchange resin) was used in packed bed reactors. The HCl catalyzed experiments were conducted in an isothermal tubular continuous reactor in laboratory scale, working in the ideal laminar flow regime. A dynamic mass balance-based reactor model was developed, including convection and molecular diffusion in axial and radial directions, as well as autocatalytic kinetics of the reaction. The model gave a very satisfactory description of the experimental data (Figure 1).

0 400 800 12000.0

0.2

0.4

0.6

0.8

1.0pH = 2.0

T = 348K T = 358K T = 368K

Inu

lin c

on

vers

ion

[-]

RT [s]A. B. Figure 1 – A. Inulin conversion as a function of residence time at different temperatures for HCl catalyzed reactions. B. Fructose yield as a function of dimensionless reactor length for SMOPEX-101 catalyzed reactions at different feed flow-rate. Concerning the SMOPEX-101 catalyzed reaction, two types of reactors were utilized: a single-bed reactor and a multibed reactor with sample withdrawal between catalyst beds. The results from the single-bed reactor allowed finding optimal reaction conditions which were extrapolated and used for the experiments in the multiple-bed reactor. The fit of the mathematical model to the experimental data was very good and this provides a useful tool for further development and scale-up purposes (Figure 1B). The results of this work highlight the potential of new reactor design strategies towards the realization of more efficient, sustainable and green processes, which can easily be scaled-up and implemented in bio-based industry. References 1. White, J.S. Sucrose, HFCS, and Fructose: History, Manufacture, Composition, Applications, and Production, in:

Springer (Ed.) 2014, 13–33. Acknowledgements: This work was funded by Johan Gadolin Process Chemistry Centre (Åbo Akademi University) and Academy of Finland.

O27PP


Selective dehydration of methanol to dimethyl ether on ferrierite nanocrystals

E. Catizzonea, S. Van Daeleb, M. Biancoa, M. Miglioria, V. Valtchevb, G. Giordanoa

aDepartment of Environmental and Chemical Engineering, University of Calabria, Rende, Italy. bLaboratoire Catalyse et Spectrochimie, CNRS, ENSICAEN, Université de Caen Basse-Normandie, Caen, France.


Tailoring of physicochemical properties of synthetic zeolites represents an intriguing aspect in the field of zeolite science, in particular when these materials are applied in catalysis1. The FER-type zeolite was recently considered as a reliable catalyst for DME synthesis via both one-pot CO2 hydrogenation or methanol dehydration2. In this work, the effect of the crystal size on the catalytic behavior of FER-type zeolites during methanol-to-DME is investigated and discussed. For this propose, three FER-type zeolites with different crystal sizes (from 0.1 nm to 10 µm) were synthesized, characterized in terms of the main physicochemical properties (e.g. crystal morphology, internal/external Brønsted/Lewis acidity, textural properties) and tested in the methanol-to-DME reaction for a wide range of reaction temperature (120-280 °C) in order to investigate the effect of crystal characteristics on methanol conversion, DME selectivity, stability and coke formation. Some results are reported in Table 1. We showed that the decrease in zeolite crystal size from micro- to nano-metric scale offers several benefits in terms of catalytic performances; for instance, an increase of methanol turnover frequency due to reduced intracrystalline mass transfer limitations was observed. Furthermore, at 280 °C, DME selectivity increases from 0.90 to 0.99 suggesting that the reduction of crystal size decreases the intra-crystalline residence time of MeOH/DME inhibiting formation of by-products (e.g. olefins). Moreover, a thorough assessment of the carbon deposition process revealed that: (i) carbonaceous consist of polymethyl benzene (PMB) molecules whose composition depends on both the crystal morphology and the reaction time (ii) coke deposition can be reduced and slowed down by using zeolites with smaller crystals (iii) the deposited coke can be removed by combustion at relatively lower temperature for nano-sized crystals.

Crystal size

[µm]

TOFa

[h-1]

DME selectivityb

[-]

Coke depositc

[mg/g]

Sample1 5-10 50 0.90 74

Sample2 0.3-0.5 65 0.95 66

Sample3 ~0.1 75 0.99 45 aTurnover frequency estimated at 180 °C bDME selectivity at 240 °C cDeposited coke after 60 h Time-on-Stream at 240°C

Table 1 – Some catalytic results

References

1. Corma, A. J. Catal. 2003, 216, 298-312. 2. Catizzone, E.; Bonura, G.; Migliori, M.; Frusteri, F.; Giordano, G. Molecules, 2018, 23, 31-58.

O28PP


Il processo catalitico di abbattimento del N2O (EnviNOx): valutazione delle performance e dell’impronta ambientale (OEF/PEF) nella filiera di

produzione del PA66.

Stefano Alini (a), Irma Cavallotti (b), Marta Ferreri (b)

(a)Radici Chimica S.p.A. via Fauser 50, 28100 Novara – [email protected] (b) ICA, Società di Ingegneria Chimica p.er l’Ambiente srl, Via Stezzano, 87 c/o Parco Scientifico Tecnologico

Kilometro Rosso, I-24126 Bergamo e-mail: [email protected]

Scopo del presente lavoro è stato quello di valutare gli effetti, in termini di impatto ambientale, degli interventi realizzati con l’installazione di un nuovo sistema di abbattimento catalitico EnviNOx, in grado di abbattere oltre agli NOx anche il protossido di azoto N2O, per il trattamento delle emissioni derivanti dal processo di produzione dell’acido nitrico. E’ stata applicata la metodologia OEF (Organization Environmental Footprint)/PEF (Product Environmental Footprint) secondo la raccomandazione 2013/179/UE al fine di valutare le performance e l’impronta ambientale. Lo studio ha dimostrato in maniera oggettiva che le modifiche impiantistiche realizzate hanno consentito la riduzione dell’impatto ambientale come valutato in fase di progettazione senza effetti negativi su altre matrici ambientali. L’analisi LCA con approccio OEF/PEF si è rivelata utile anche per individuare altre possibili aree di miglioramento all’interno dello stabilimento ed è quindi un ottimo strumento di supporto alla Direzione per prendere decisioni inerenti la sostenibilità dei prodotti o dei processi. Per questo tipo di utilizzo richiede tuttavia un approccio sequenziale, cioè lo studio deve essere ripetuto nel tempo. In una visione più allargata l’approccio PEF si presenta come un ottimo strumento per comunicare i valori d’impatto ai Down Stream Users e consentire anche a loro di calcolare la PEF sui prodotti che vengono effettivamente immessi sul mercato per l’utente finale. In quest’ottica può essere uno strumento anche di “supply chain optimization”.

O29PP


Sessione Poster

Lunedì 3 Settembre


Laccase pretreatment for agrofood wastes valorisation

C. Pezzellaa,b, S. Giacobbeb, V. Letterab, A. Piscitellia,b,G. Sanniaa,b aUniversità Federico II, Dipartimento di Scienze Chimiche, Napoli, Italy.

bBiopox srl, Napoli, Italy. e-mail: [email protected]

Agrofood wastes (AFWs) are attractive feedstocks for the production of biofuels, due to their abundance and high carbohydrate content. As lignocellulosic biomasses, AFWs conversion is challenged by the presence of lignin, a recalcitrant structure that prevents enzymatic hydrolysis of sugars. In this work, three AFWs, apple residues, potato peels, and coffe silverskin, were selected based on the European availability, carbohydrate content and market price. The effectiveness of a laccase based pretreatment to improve saccharification of analysed AFWs was assessed. Enzymatic pretreatment of the analysed AFWs was carried out at 28°C for 24h by using different combinations of Pleurotus ostreatus laccase mixes (mix1 and mix2)1,2, in presence or absence of vanillin as natural mediator. Optimized conditions were assessed for all biomasses reaching partially delignification and high detoxification yields. The lignin and phenols reduction were directly correlated with an improvement of enzymatic saccharification. Obtained results claimed that laccase mixes alone allowed to obtain high sugars yield with the following order: apple residues > coffee silverskin > potato peels. Especially noteworthy was the effect of laccase pretreatment on apple residues, for which up to 40% of lignin reduction was observed, resulting in high sugar recovery (83%).

References

1. Palmieri, G. Appl. Environ. Microbiol 2000, 920-924 2. Pezzella, C. J. Biotechnol. 2017, 175-181.

Acknowledgements: This work was funded by the research project Waste2Fuels ‘Sustainable production of next generation biofuels from waste streams’ (N. 654623), funded under the European Union’s research and innovation program Horizon 2020

SPL01


Metagenomics: a valuable source of novel enzymes from non-cultivable microbes

F. Berinia,b, F. Marinellia,b

a Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy. b The Protein Factory research center, Politecnico di Milano and University of Insubria, Milan, Italy.


There is a growing demand for novel biocatalysts with high process performances to be used for replacing traditional chemistry with a more ‘green’ environmental-friendly approach. To date, microorganisms encompass by far the richest source of biocatalysts used in industrial sectors. Notwithstanding this extraordinary contribution, the major part of the microbiota in natural ecosystems (up to 99-99.9%) risks to remain untapped, due to its unculturability by using traditional isolation and cultivation methods. To avoid this, in the last two decades different culture-independent methods have been developed. Among them the metagenomics, i.e., the analysis of the collective genome of an entire microbial community by DNA direct extraction, is considered the most likely and promising methodology for the identification of new and innovative biocatalysts. Indeed, metagenomics-based studies have been applied to a range of environments, including terrestrial, marine and freshwater habitats, as well as wastewater treatment sludges, compost, and extreme environments. Similarly various are the enzymes targeted in metagenomic investigations, which include glycosyl hydrolases (cellulases, hemicellulases, amylases, chitinases), lipases/esterases, oxidoreductases, and proteases, just to cite a few. The number of biocatalysts discovered by metagenomics is astonishing: a literature analysis indicated that from January 2014 to March 2017, more than 300 novel metagenome-sourced enzymes were identified and at least partially characterized [1]. With the aim of identifying enzymes involved in the degradation of recalcitrant biomasses, in the frame of the EU MetaExplore consortium, we applied ad hoc activity- and/or sequence-based screenings to different metagenomic libraries, leading to the discovery of novel biocatalysts. Among them, our work is currently focused on two chitinases, called Chi18H8 [2,3] and 53D1 [4], and one laccase, LacM [5]. The biochemical and functional characterization of these proteins revealed that they had interesting and useful feature: after having developed efficient protocols for their production/purification, we are testing their activity and applicability in different industrial and agricultural processes.

1. Berini, F. et al. FEMS Microbiol. Lett. 2017, 364(21). 2. Hjort, K. et al. Appl. Microbiol. Biotechnol. 2014, 98(6), 2819-2828. 3. Berini, F. et al. Microb. Cell. Fact. 2017, 16(1), 16. 4. Cretoiu, M. S. et al. Appl. Microbiol. Biotechnol. 2015, 99(19), 8199-8215. 5. Ausec, L. et al. Appl. Microbiol. Biotechnol. 2017, 101(15), 6261-6276.

Acknowledgements: This work was funded by the EU FP7-KBBE project MetaExplore -grant agreement No 222625-, and by MAECI (Ministero degli Affari Esteri e della Cooperazione Internazionale) for the Chitobiocontrol project – agreement of scientific, technological and industrial cooperation between Italy and Israel, industrial track. MIUR fellowship to FB is acknowledged.

SPL02


Mo-doped TiO2 nanoparticles obtained by sol-gel templated assisted synthesis: photocatalytic and physico-chemical properties

R. Nasi,a T. A. Gadhi,a S. Esposito,b N. Ditaranto,c S. Hernandez,a M. Armandi,a Barbara

Bonelli*a

a Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy.

b Dip. di Ingegneria Civile, Chimica e Ambientale, Università degli Studi di Genova and INSTM Unit Genova, via all’Opera Pia 15A, Genova, Italy.

c Dip. Chimica, Università degli Studi di Bari "Aldo Moro" via Orabona 4, I-70125, Bari, Italy


TiO2 anatase is a very promising photocatalyst and has been extensively studied. Transition metal ions doping not only affects the band gap and increases the optical absorption in visible range, but also leads to changes in the oxidation state and redox potentials as well as structural parameters, which play a primary role in the photocatalytic activity [1]. Molybdenum based catalysts have shown promising activity because of the low oxidation potential and high Lewis acidity in the highest oxidation state [2]. Inverse micelle sol-gel method was used to produce mesoporous MoOx-TiO2 nanoparticles (with a diameter of ca. 20 nm) of different compositions (from 1 to 10 %w Mo/(Mo+TiO2)) with a surface area of ca. 90 m2/g. Characterization of the produced samples was performed by X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and N2 adsorption measurements. Finally, photocatalysis experiments were conducted using a model rhodamine-B (Rh−B) dye reaction using visible irradiation source showing that a fast photodiscoloration of the dye can be achieved using the synthetized nanomaterial under visible light.

References 1. M. R. Hoffmann, S. T. Martin, W. Choi and D. W. Bahnemann Chem. Rev.1995, 95, 69−96. 2. J. Tang, B. Kong, Y. Wang, M. Xu, Y. Wang, H. Wu and G. Zheng, Nano Lett. 2013, 13, 5350-5354.

SPL03


Photodegradation of (emerging) N-containing pollutants in wastewater

F. S. Freyria,a M. Compagnoni,b E. Bahadori,b T. A. Gadhi,a N. Ditaranto,c M. Armandi,a I. Rossetti,b G. Ramis,d B. Bonelli*a

a Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy.

b Dip. Chimica, Università degli Studi di Milano, INSTM Unit Milano-Università and CNR-ISTM, via C. Golgi, 19, I-20133 Milano, Italy.

c Dip. Chimica, Università degli Studi di Bari "Aldo Moro" via Orabona 4, I-70125, Bari, Italy dDip. di Ingegneria Civile, Chimica e Ambientale, Università degli Studi di Genova and INSTM Unit Genova, via

all’Opera Pia 15A, Genova, Italy.


In aquatic environments, such as rivers, lakes, etc., it is possible to find a noteworthy number of emerging pollutants (EPs), which are compounds that are not commonly removed, but might cause negative ecological and human health effects by entering the environmental system. Among these, N-containing pollutants, such as simazine, phenyl urea, diazepam, azo-dyes are particularly dangerous, since they are recalcitrant to the current remediation methods and due to the toxicity of their sub-products. We have been studying the degradation of some organic N-containing pollutants under illumination (both UV and solar light), in the presence of either pure or doped mesoporous TiO2 (MT). Different transition metals (V, Fe and Mo) have been used to dope the MT samples, (obtained by template-assisted syntheses) with the main aim of red-shifting the band-gap of the catalyst and to harvest a larger fraction of the visible spectrum. Another set of samples was obtained by impregnation of either MT and commercial TiO2 (Degussa P25) and was used for comparison. The samples were characterized by X-ray powders diffraction, N2 adsorption isotherms at -196°C, SEM and Energy Dispersive X-ray Spectroscopy, Diffuse Reflectance UV-Vis and X-ray Photoelectron Spectroscopy. The samples doped by direct synthesis showed nanoparticles of pure

anatase (≈15 nm diameter), with high specific surface area (120 – 150 m2 g-1). The effects have been studied of different H2O2 concentrations and different type of illumination (UV vs. solar light) on the photodegradation activity. Different reaction mechanisms have been found, depending on both chemical composition and preparation method (Scheme). Very promising results1

have been obtained with the samples prepared by direct synthesis with a total content of 2.5 wt.% Fe under simulated solar light.

Scheme References F. S. Freyria, M. Compagnoni, N. Ditaranto, I. Rossetti, M. Piumetti, G. Ramis, B. Bonelli Catalysts. 2017, 7, 213.

SPL04


Noble Metal Replacement in Catalytic Biomass Conversion: Molybdenum as modifier of Pt-C catalysts for Furfural Transformation.

M, Stucchia, S. Cattaneoa, I. Barloccoa, J. Lizarazub, L.Pratia and A. Villaa

a Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi 19, 20133 Milano, Italy. b University of the Basque Country - UPV/EHU, Faculty of Chemistry of San Sebastian, Spain.


Furfural derives from biomass through hemicellulose conversion by hydrolysis and further xylose cyclodehydration [1]. Furfural selective hydrogenation and hydrogenolysis result mainly in C5 value-added chemicals [2] (Scheme 1). Although noble metal-based catalysts effectively transform biomass resources [3], they have high costs and limited availability. Decrease the amount of noble metal into catalytic system, could be beneficial in terms of both economic and environmental impact. Transition metals constitute a possible alternative and many papers reported that the introduction of transition metal into noble-metals based catalysts had a significant influence on the catalytic activity and selectivity [4-5]. Here, we investigated the behavior of Mo and Pt/Mo supported on activated carbon (AC) derived from birch wood in furfural hydrogenation. Furfural hydrogenation reactions was carried out in a batch autoclave at 50 °C and 3 bar of hydrogen.

Catalyst (substrate/metal ratio=500, mol/mol) was suspended in 10 ml of furfural solution (0.3 M in EtOH). GC analyses showed the furfural conversion and products formation over time (6 h). 40% Mo/AC representative TEM image is shown in Figure 1. A similar metal dispersion has been observed when 1 % Pt was added for obtaining bimetallic catalyst. Both Pt and Mo supported on AC were able to convert furfural to furfuryl alcohol and tetrahydrofurfuryl alcohol. Also, GC analysis showed the formation of the ether from the reaction between substrate and solvent. However, we found a different products distribution comparing the two metals. Moreover, the presence of Mo influenced both the activity and selectivity of the Pt-supported catalyst, showing a different ratio between alcohols and ether.

References 1. Xing, R., Qi, W., Huber, G. W. Energy Environ. Sci. 2011, 4(6), 2193−2205. 2. Sun, Y., Cheng, J. Bioresour. Technol. 2002, 83, 1– 11 3. Li, X., Pei, J., Wang, T. ACS Catal. 2016, 6(11), pp 7621–7640. 4. Gallezot, P. Chem. Soc. Rev. 2012, 41, 1538–1558. 5. Villa, A., Campisi, S., Giordano, C., Otte, K., Prati, L. ACS Catal. 2012, 2, 1377−1380.

Fig. 1 HR-TEM image of Mo/AC catalyst

Scheme1. C5 chemicals from furfural hydrogenation/hydrogenolysis.

SPL05


Photocatalytic processes for water treatment: removal of N-containing pollutants

Elnaz Bahadoria, Antonio Tripodia, Ilenia Rossettia, Gianguido Ramisb


b DICCA, Università degli Studi di Genova, INSTM Unit Genova, via all’Opera Pia 15A, Genova, Italy


Nitrogen containing pollutants, such as ammonia, nitrites and nitrates, are substances of concern due to their increasing amount in water, mainly in agriculturally intensive areas. They are correlated to many health issues, especially for infants and children, as well as with environmental problems given they are nutrients and induce uncontrolled increase of algal growth, especially in closed basins. Conventional biological treatment is insufficient to remove these pollutants from water, so that a tertiary specific treatment is needed. Photocatalytic processes may be effective for the oxidation of ammonia and the reduction of nitrites and nitrates [1,2]. However, in the literature these processes are poorly explored and, furthermore, the attention is mainly focused on the materials rather than on reactors and process set up. Furthermore, scale up issues are mostly unaddressed. Therefore, in this work we focused on some simple TiO2-based materials, in case added with Ag, Au, Pt or Pd as co-catalysts, for the photocatalytic removal of NH3, NO3

- and NO2-. The activity of each sample was compared by using

two different slurry type photoreactors, ca. 300 mL in volume, operated either in batch or semibatch mode. In the latter case air or inert gas was continuously flown during the photooxidation or photoreduction, respectively. Ca. 32% ammonia conversion was achieved over Pd/TiO2 sample in 5 h, with 100% selectivity to N2. Nitrate photoreduction was less effective, leading to max 10.5% conversion after 5 h, but with insufficient selectivity to N2 (44% NH3 selectivity). These results have been combined with the treatment of the same model solutions with sludge of a water treatment plant, which evidenced that the biological nitrate reduction treatment was effective and sufficiently selective, whereas ammonia oxidation activity was by far unsatisfactory. Therefore, a two step process can be designed, with a first NOx

- photocatalytic or biological reduction stage, followed by the photooxidation of ammonia, abating the one originally present and the one possibly formed during the reduction step. Finally, process scale up has been addressed, testing some of the most interesting materials in a 10 L photoreactor c/o the ISWA facility in Stuttgart, Germany with real waste water. Maximum ammonia conversion of 4 % was achieved with commercial TiO2 (P25 by Evonik) after 30 minutes (maximum allowed reaction time) with competitive oxidation of organics. Indeed, the COD abatement after 30 minutes of reaction was 20-30%.

Acnowledgements The authors are grateful to Fondazione Cariplo (Italy) for financial support (2015-0186 “DeN – Innovative technologies for the abatement of N-containing pollutants in water”). I. Rossetti and E. Bahadori are grateful to Fondazione Cariplo and Regione Lombardia for financial support (2016-0858 – “Up-Unconventional Photoreactors”). References

1. Compagnoni, M.; Ramis, G.; Freyria, F.S.; Armandi, M.; Bonelli, B.; Rossetti, I. Journal of Nanoscience and Nanotechnology, 2017, 17, 3632–3653.

2. Freyria, F.S.; Armandi, M.; Compagnoni, M.; Ramis, G.; Rossetti, I.; Bonelli, B. Journal of Nanoscience and Nanotechnology, 2017, 17, 3654–3672

SPL06


Process simulation of ammonia synthesis over optimized Ru/C catalyst and multibed Fe + Ru configurations

Antonio Tripodi, Elnaz Bahadori, Ilenia Rossetti

Chemical Plants and Industrial Chemistry Group, Dip. Chimica, Università degli Studi di Milano, INSTM Unit Milano-Università and CNR-ISTM, via C. Golgi, 19, I-20133 Milano, Italy


Ammonia synthesis over different Iron- and Ruthenium-based catalysts was modelled with appropriate rate equations, used for the simulation of the process under different configurations and operating conditions. The kinetic models have been validated against experimental data. The classic Temkin equation was used for Fe-based catalysts, either derived from magnetite or wustite, while a modified Temkin model was used to describe the Ru-based material, to account for the much lower inhibition by NH3, but higher for H2 with respect to Fe [1,2]. A scaled up reactor has been designed, at first with a once through configuration. On this model reactor we performed a sensitivity analysis to optimise the reaction conditions. Then, the sizing of an ammonia separation unit and the optimisation of the recycle loop allowed to compare different possible configurations. A multibed catalytic reactor with intercooling was then designed, using the same catalyst or combining different catalyst types so to maximise the ammonia productivity. In particular, Fe-based catalysts were used in the first catalytic bed(s), followed by the Ru/C one, in order to push the ammonia productivity towards the equilibrium value. The process has been modelled with Aspen Plus process simulator according to the following scheme. The best conditions for the single-pass operation of the Ru/C material were selected in the 400 – 450 °C range, while the decrease of the operating pressure from 125 to 100 bar can decrease the gross compressors duty by ca. 7%. A multibed reactor configuration, with intercooling, was selected, holding different catalyst amounts and types. Mixing initial iron-based catalysts in the first bed(s) with Ru-based catalyst in the last one(s) revealed the best option to improve the yield with optimised catalyst loading. Accordingly, less demanding operating conditions can be envisaged for mixed multibed configurations.

References

1. Rossetti, I.; Pernicone, N.; Ferrero, F.; Forni, L. Ind. Eng. Chem. Res., 2006, 45, 4150. 2. Pernicone, N.; Ferrero, F.; Rossetti, I.; Forni, L.; Canton, P.; Riello, P.; Fagherazzi, G.; Signoretto, M.; Pinna, F.

Appl. Catal. A: General, 2003, 251, 121.

SPL07


Genesis of the active sites in the Cr/SiO2 Phillips catalyst for ethylene polymerization

G. A. Martino,a A. Piovano,a C. Barzan,a S. Bordiga,a E. Groppoa

aDepartment of Chemistry, NIS and INSTM, University of Torino via Quarello 15A, 10135 Torino, Italy. e-mail: [email protected]

Producing annually more than 30 MTons of High Density Polyethylene (HDPE) (i.e. about one third of the polyethylene global production capacity), the Cr/SiO2 Phillips catalyst is one of the world’s most important industrial catalysts since more than half a century.1 It is also among the most investigated and yet controversial catalytic systems. Indeed, despite the apparent simplicity of its chemical formulation (Cr ions at the surface of amorphous silica), the Phillips catalyst remains largely mysterious. A crucial point of debate concerns the mechanism through which the ethylene polymerization reaction is initiated at the Cr sites in the presence of ethylene (i.e. the genesis of the active sites). This question is strictly connected to the Cr oxidation states and conflicting views are present in the literature. Unlike other widely used olefin polymerization catalysts, such as the Ziegler-Natta and metallocene catalysts, the Phillips does not require the use of any alkylating co-catalyst to trigger the activity. In contrast, aluminum-alkyls are used in the industrial practice to promote in situ branching, decrease the induction time and enhance the sensitivity to H2 for the molecular weight regulation.

In this contribution, we will review a series of recent results obtained by our research group by applying sensitive spectroscopic techniques to investigate the genesis of the active Cr sites in the Phillips catalyst, in the absence2 and in the presence of Al-alkyls. A critical discussion of our results in comparison to the literature will be done. References 1. McDaniel, M.P. Adv. Cat. 2010, 53, 123. 2. Barzan, C., Piovano, A., Braglia, L., Martino, G. A. Lamberti, C., Bordiga, S., Groppo, E., J. Am. Chem. Soc. 2017,

139, 17064−17073.

SPL08


Low temperature regenerating catalytic Diesel Particulate Filter

E. Melonia, V. Palmab aUniversity of Salerno, Department of Industrial Engineering, Fisciano (SA), Italy

b University of Salerno, Department of Industrial Engineering, Fisciano (SA), Italy e-mail: [email protected]

Diesel engines are widely used thanks to good performance in terms of fuel consumption, drivability, power output and efficiency, but the high heterogeneity of the charge in the combustion chamber leads to a simultaneous production of NOx and soot emissions, two pollutants very harmful to the environment1. The current Euro-6 legislation for light-duty vehicles imposes very strict targets to be reached for these pollutants, and these standards are difficult to meet with combustion optimization techniques. In such a scenario it is clear that the after-treatment is mandatory and Diesel Particulate Filter (DPF) is the most common system available on commercial vehicles2. Wall-flow DPF consist of a series of parallel channels alternatively plugged at each end to force the exhaust gas flow through the porous filter wall. During engine operation, the soot is trapped in the filter with an increase of exhaust back-pressure, therefore a regeneration process is required. In our previous works we studied soot deposition and on-line filter regeneration, showing that the simultaneous use of microwaves and copper-ferrite catalytic filter at low gas flow rate allows to reduce the energy supplied and the regeneration time compared to that required for the uncatalysed filter3. In this work we optimized the formulation of the copper-ferrite catalytic filter in order to simultaneously improve the catalyst MW dissipation efficiency and the final catalytic DPF performance, to maintain a sustainable pressure drop, and to verify the feasibility of this technology by assessing the energy balance of the regeneration phase in comparison with current regeneration technologies. The results of the catalytic filters characterization showed that the optimized4 preliminary acid treatment of the bare SiC monoliths resulted in an increased average pore diameter of the catalytic samples, if compared with the analogues without acid treatment. The modified porosity had a very positive effect on filter perfomance, since the on-line soot deposition tests (figure 1) showed that in the case of filters with a 20%wt copper ferrite loading but different porosity the DP limit value corresponding to a soot load of about 5 g/l of filter was reached in about 450 and about 750 minutes, consequently decreasing the regeneration step frequency. In addition the further increase of copper ferrite loading up to 30%wt on a modified porosity filter resulted in a soot deposition phase time still longer than the one of the unmodified filter but with a lower loading of catalyst. This very important result allows to obtain two fundamental consequences, (i) to increase the duration of the deposition phase, and (ii) the higher catalyst loading resulted in a higher catalytic activity during the regeneration phase (figure 2). In fact the filter with a simultaneous porosity modification and a higher catalyst loading (30%wt of copper ferrite) showed a threshold catalyst temperature decreased to about 350°C, and a regeneration step duration decreased from about 22 to about 15 minutes.

References 1. T.G., Vlachos, P., Bonnel, A., Perujo, M., Weiss, P.M., Villafuerte, F., Riccobono, SAE Int J Commer Veh, 2014, 7 (1),199–

215 2. M., Bergmann, U., Kirchner, R., Vogt, T, Benter, Atmospheric Environment, 2009, 43, 1908-1916 3. E. Meloni, V. Palma, V. Vaiano, Fuel, 2017, 205, 142 – 152 4. V. Palma, E. Meloni, Fuel, 2016, 181, 421 – 429

Figure 1. Effect of modified porosity and CuFe2O4 loading on SiC monoliths in terms of pressure drop (DP/DP0) during the soot deposition phase as function of the test time

Figure 2. Effect of modified porosity and CuFe2O4 loading on SiC monoliths in terms of pressure drop (DP/DP0) and temperature profile during the microwave assisted regeneration phase as function of the test time

SPL09


NH3-SCR catalysts for lean-burn natural gas vehicles: CH4 effect on deNOx

catalytic activity

R. Villamainaa, I. Novaa, E. Tronconia, T. Maunulab, M. Keenanc a Department of Energy, Laboratory of Catalysis and Catalytic Processes, Politecnico di Milano, Milano, Italy

bDinex Ecocat Oy, Global Catalyst Competence Centre, Vihtavuori, Finland cRicardo UK Ltd, Shoreham Technical Centre, Shoreham-by-Sea, UK


One of the main goals in the field of transportation is the reduction of harmful emissions from combustion sources. The control of NOx emissions from mobile sources, necessary to comply with the current European emission standards, can be effected through primary and secondary measures. Among the secondary measures, the Selective Catalytic Reduction (SCR) with NH3/urea is nowadays considered the most effective technology for the abatement of NOx emissions from Diesel and other lean burn engines [1]. This work focuses on the study of the NH3-SCR technology for after-treatment systems of heavy-duty vehicles equipped with lean-burn natural gas engines. In particular, the aim is to test and compare different classes of well-known NH3-SCR catalysts under reference conditions typical of heavy duty vehicles with lean-burn natural gas (NG) engines. The NH3-SCR activity of two aged state-of-the-art SCR catalysts supplied by Dinex Ecocat [2], namely an Fe- and a Cu-zeolite, both coated onto corrugate metal sheets, was investigated in all the main reactions typical of the NO-NO2/NH3-SCR reacting systems varying the NO2/NOx feed ratio. Then the results were compared with those obtained in the same reacting systems with the addition of CH4, in order to simulate the typical conditions of the after-treatment systems (ATS) of lean-burn NG vehicles. Moreover, the reactivity of CH4 with NOx was also specifically addressed. The best performance of each catalyst was obtained with the NO2/NOx feed ratio equal to 0.5 due to the occurrence of the Fast SCR reaction. In particular, over Cu-zeolite and Fe-zeolite catalysts, NH3 conversions reach about 100% already at 200 °C while NO conversions exceed 90% in the low temperature region. Instead, under Standard SCR conditions (NO2/NOx=0) the catalysts showed different behaviors: the Cu-zeolite has a superior low temperature deNOx activity, while the Fe-zeolite is characterized by greater deNOx activities and N2 selectivities at high temperatures. A sequential arrangement of the two metal-promoted zeolites was therefore investigated to verify if it is possible to combine the high low-temperature deNOx activity of Cu-zeolite with the greater high-temperature deNOx activity of Fe-zeolite. The combination of the two zeolites with the Fe-zeolite upstream indeed granted an excellent compromise over the whole temperature range, also with respect to the undesired formation of N2O. Concerning the CH4 effect, under Standard and Fast SCR conditions all the catalysts showed exactly the same behavior in presence and in absence of the hydrocarbon and then CH4 can be considered as an inert in NH3-SCR under these operating conditions. However, under NO2-SCR conditions, CH4 exhibited a reactivity with NO2 at T>400°C, specifically a higher NO2 reduction to NO was observed when CH4 was present in the gas mixture, in correspondence of a production of COx due to the oxidation of CH4. Dedicated experiments under specific oxidizing conditions were also performed in order to explore such a reactivity: CH4 can be effectively oxidized to COx by NO2+O2 already at 300°C over all the investigated catalytic systems.

References 1. Nova, I. Tronconi, E. (Eds.), “Urea-SCR Technology for deNOx After Treatment of Diesel Exhausts”, Springer,

New York, 2014 2. Maunula, T. and Wolff, T. SAE Technical Paper 2016-01-2214, 2016.

Acknowledgements: The research leading to these results has received funding from the European Community’s Horizon 2020 Programme under grant agreement No. 653391 (HDGAS).

SPL10


Preparation of Structured Catalysts by Chemical Conversion Coating for the CO-Water Gas Shift Reaction

V. Palma, M. Martino

University of Salerno, Department of Industrial Engineering, Via Giovanni Paolo II 132, 84084 Fisciano (SA), Italy e-mail: [email protected]

The CO-Water Gas Shift (WGS), operating downstream of the reforming processes, allows to reduce the percentage of carbon monoxide in syngas stream to less of 0,3 vol%, increasing the yield in hydrogen, therefore it can be considered the first purification step of hydrogen, upstream of important processes such the ammonia synthesis. WGS is an exothermic reversible reaction, thermodynamically favored at low temperature; the industrial process provides two adiabatic stages, High Temperature Shift (HTS) and Low Temperature Shift (LTS), with an intermediate cooling1. The heat of the reaction induces a thermal gradient on the catalytic bed, with a much higher temperature at the outlet of the bed, with respect the inlet, limiting the CO conversion. The strategy currently used to overcome these limitations, is a two-stages process, that allows the most of the conversion in a short time in the HTS, and allows to reach high conversion in the LTS. The multi-stage reactors allow to obtain the kinetically optimum reaction pathway, with a large number of small steps, but of course the plant and operating costs must be weighed up against the productivity of the global configuration. Moreover the growing need of small-scale plants, in the distributed production of hydrogen as energy vector, make this kind of configuration unsuitable and unprofitable. From the above consideration, it is clear that a strong intensification of the WGS process, is highly advisable; in particular our group focused the attention on the preparation and the study of structured catalysts, based on highly conductive aluminum foams2. In this work we present our results on the use of structured catalysts for the WGS reaction, obtained by chemical conversion coating with a cerium chloride plating bath, of aluminum foams.

The plated foams catalyst showed high resistance to the mechanical stress with respect the washcoated foams catalyst. The activity of the catalysts was related to their specific surface area, and reducibility, while a stability test highlighted the instability of the plated catalysts, probably due to the coke formation. References

1. Palma, V., Pisano, D., Martino M., Ciambelli P. Chem. Eng. J. 2016, 304, 544. 2. Palma, V., Pisano, D., Martino M. Int. J. Hydrogen Energ. 2017, 42, 23517.

Acknowledgements: This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 734561".

SPL11


Towards air emission control system based on Plasma-Catalysis

C. M. Brancatoa,b, S. Morandia, K. Costabellob, F. Parisib, S. Bordigaa

aDipartimento di Chimica and NIS Interdepartmental Centre, Università di Torino, Via Giuria 7, 10125 Torino, Italy. bGrinp s.r.l., Via A. de Francisco 123, 10036 Settimo Torinese (TO), Italy.


The abatement of pollution at its source is one of the overarching principles of the Thematic Strategy on Air Pollution (communication from the Commission of the European Communities to the Council and the European Parliament). For these reasons, in recent years, different systems for removing pollutants have been studied, but these still have many disadvantages, constrain and limitation. In particular, many air remediation approaches require high temperature, large installation to become interesting in respect to real applications, they present high costs and lead to low yields. The coupling between plasma systems and heterogeneous catalysts has received growing attention in the last years due to its attractive and efficient success at room temperature in the removal of polluting molecules for environmental applications [1,2]. Heterogeneous catalysts can be combined with plasma in two ways: in-plasma catalysis (IPC), with the catalyst inside the reactor or post-plasma catalysis (PPC), with the catalyst downstream of the reactor (Scheme 1). Plasma-catalysis can be defined as any combination of plasma with a catalyst, resulting in an improvement of the processing of the input gaseous stream. Commonly, it is more often referred to a narrower category of gas stream processing, specifically the treatment of waste gas or polluting contaminants usually by employing non-thermal plasma (NTP) at atmospheric pressure. Plasma-catalysis is used not only in oxidizing conditions (VOC abatement) but also in reducing process (NOx abatement) with the aid of different specific catalyst. However, the reducing conditions for a plasma-catalyst system are less well-known than the oxidizing ones. Consequently, the coupled plasma-catalyst system able of working in a reducing environment will be expected to require greater attention from the scientific and industrial world. Our work is focused on the design, development, testing and validation of an innovative, multi-contaminant, flexible air emission control system, for the active and efficient reduction of pollutants deriving from the widest range of industrial and agricultural activities. For pursuing this big outcome, we started to focus the attention on the VOCs abatement. Four MnOx-based catalysts were chosen and tested in CO and toluene oxidation: two catalysts are commercially available and sold by Haldor Topsøe and Sasol, the other two were synthesized. The final purpose is the in-plasma catalysis, but, first of all, it was important to characterize the catalysts in a reactor without the plasma assistance. Their catalytic performances were tested at different temperature by monitoring the gas phase composition and the surface species formed during the catalytic run. The surface species were characterized by in situ and operando FT-IR spectroscopy. The catalyst with the best performances will be introduced in the plasma system. The introduction in the plasma is a crucial step that is requiring a lot of efforts for setting the best operation methodology. References

1. Talebizadeh, P.; Babaie, M.; Brown, R.; Rahimzadeh, H.; Ristovski, Z.; Arai, M. Renewable and Sustainable Energy Reviews 2014, 40, 886-901.

2. Sultana, S; Vandenbroucke, A. M.; Leys, C.; De Geyter, N.; Morent, R. Catalysts 2015, 5, 718-746.

Scheme 1. Schematic diagram of

continuous plasma‐catalysis processes [2].

SPL12


Synthesis of methanol from biosyngas

F. Gallia, L.M. Cipollaa, D. Previtalib, A. Di Michelec, G. Bozzanob, M. Manentib, C. Pirolaa

aUniversità degli Studi di Milano, Dipartimento di Chimica, via Golgi 19, 20133 Milano, Italy. bPolitecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", piazza Leonardo da

Vinci 32, 20133 Milano, Italy. cUniversità degli Studi di Perugia, Dipartimento di Fisica, via Pascoli 1, 06123 Perugia, Italy


In the last 2 years, 4345 scientific documents have been published regarding carbon dioxide capture and storage (CSS) (research made the 9/2/2018 in the TOPIC field of the Web of Science Core Collection with the keywords “(carbon dioxide capture) OR (Carbon capture and storage)”). Carbon capture technologies rely on the adsorption or mineralization of carbon dioxide over solids or liquids. However, high process costs and technical issues such as corrosion limit the expansion of CSS at larger scale. Hansan et al. estimated that the sequestration of streams with a concentration of CO2 higher than 10 % costs between 30 and 70 $/ton CO2, depending on the flowrate and composition of the exhausted [1]. Converting CO2 into chemicals or fuel is a strategy that enables the reuse of the carbon instead of landfilling it. An analysis on recent papers (Web of Science Core Collection, year 2015-2017, keywords “(CO2 conversion) OR (CO2 hydrogenation)”) reveals that the research is focusing on selective hydrogenation to give syngas, methane and various liquid products. Here, we converted biosyngas, i.e. a mixture of CO, H2 and CO2 into methanol. H2 to CO molar ratio (stoichiometric) was always 2 whereas CO2 concentration varied between 0 and 13 %vol. The catalyst was a commercial CZA (mixture of Cu, Zn and Al oxides, from Alpha Caesar ID: 45776), which is the most employed catalyst for methanol production [2]. Its typical composition is: CuO 63.5 %wt, ZnO 24.7 %wt, Al2O3 10 %wt and MgO 1.3 %wt. We collected all the data in a lab scale fixed bed reactor. Its diameter is 6 mm. Four mass flow controllers set the flow of CO, H2, CO2, and N2 (internal standard for the analytical part). A type K thermocouple measured the temperature of the catalytic bed and a Brooks pressure controller back regulated the pressure to a value between 20 and 35 barg, depending on the test. A cold trap at 3 °C condensed water, methanol and eventually any other by-products. A Ritter TG01/05 totalizer quantified the total volume flowed in the plant from the beginning of each test. A micro-GC (Agilent 3000A) measured the unreacted CO flowrate (Eq. 1). SEM, TEM, TPR, and XRD characterized the catalysts. Before each test, we activated the catalyst at 5 bar and 300 °C with 50 NmL min-1 of H2 for 4 h.

(1)

From the mass balance, we derivated CO conversion. Methane and carbon dioxide were the main byproducts. Equation 2 calculated products selectivity:

(2)

where all the flowrates are expressed in mol min-1. CO conversions increased with total pressure (5 %, 6.3 % and 7 % at 230 °C respectively at 20, 25 and 30 bar). The higher the temperature, the higher the conversion. At 20 bar, CO conversion is 5 % at 230 °C and 12 % at 250 °C while it is 15 % at 270 °C. However, byproducts selectivity raises at 270 °C. CZA catalyzed methanol production and biosyngas may be employed as new potential feedstock for this process. References

1. Hasan, M.M.F., Baliban, R.C., Elia, J.A., Floudas, C.A. Ind. Eng. Chem. Res. 2012, 51, 15642-15664. 2. Klier, K., Chatikavanij V., Herman R.G., Simmons J.W. J. Catal. 1982, 74, 343-360.

SPL13


Influence of phosphate groups in Guerbet reaction

G. Innocentia, D. Manzinib, J. Velasquez-Ochoaa, I. Rossettib, F. Cavania aDipartimento di Chimica Industriale “Toso-Montanari”, Università di Bologna, Bologna, Italy.

bDipartimento di Chimica, Università degli Studi di Milano and INSTM Unit Milano-Università, Milan, Italy.

e-mail: [email protected] n-Butanol is a widely used additive in daily use products (such as paints, skin care products...) and an important chemical intermediate to produce more valuable compounds; moreover, it is thought to be a valid alternative to gasoline. To date, n-butanol is mainly produced via oxo-synthesis which relies on petrochemical sources. The demand for an efficient green chemical route has highlighted the Guerbet condensation of alcohols.1 The reaction mechanism of this reaction is still subject of debate. The widely-accepted mechanism, that involves a first dehydrogenation step followed by the aldol condensation and a hydrogenation step has been recently discarded on MgO and basic zeolites.2 In fact, in 2015 a direct condensation of two ethanol molecules involving a carbanion intermediate has been proposed as reaction pathway.3 Several catalysts have been tested in this reaction but the selectivity to butanol obtained using hydroxyapatite (calcium hydrogen phosphate) is still the highest ever reported in the literature for the gas phase.1 In order to understand how the phosphate group influence the reaction in terms of both selectivity and reaction mechanism, it was decided to impregnate MgO (that is known to be a quite unselective catalyst) with different H3PO4 amounts (0.5, 1 and 5 w/w %) by means of incipient wetness impregnation. The catalysts were, then, tested in a bench scale gas-phase continuous flow reactor. The catalytic activity was studied as function both of temperature and contact time. In Figure 1 it is reported a comparison among the catalyst performances at 350 °C and 1 g s ml-1. In terms of conversion, MgO is similar to the impregnated catalysts. On the contrary, the MgO butanol selectivity is almost doubled even in presence of small amount of H3PO4. The best catalyst seemed to be the one containing 5% H3PO4 since it shows high butanol selectivity, low carbon loss and the lowest selectivity to other products. Hence, a complete catalytic study has been carried out on this sample. Finally, both this sample and MgO will be studied by DRIFTS in order to highlight the differences that lead to such different behavior. References 1. Gabriels, D. et al, Catalysis Science & Technology 2015, 5 (8), 3876-390 2. Scalbert, J. et al, Journal of Catalysis 2014, 311, 28-32. 3. Chieregato, A. et al ChemSusChem 2015, 8 (2), 377-388.

Acknowledgements: The Valsovit project is co-funded by the Emilia Romagna Region through the POR FESR 2014-2020 funds (European Regional Development Fund).

Figura 1 Comparison among MgO, 0.5% H3PO4/MgO, 1% H3PO4/MgO and 5% H3PO4/MgO catalytic performances at 350 °C and 1 g s ml-1

SPL14


Dry Reforming of Methane in Catalytic Membrane Reactors

R. Garcia de Castroa, A. Comitea, V. Perronea a Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Genoa, Italy.

e-mail: [email protected] There has been a recent growing interest in the dry reforming of methane (DRM) reaction, since it offers some advantages face to the traditional hydrogen production pathways, such as steam reforming (SR). This pathway is inevitably associated to the appearance of CO2, generally released into the atmosphere as a waste product. Instead, DRM products contain relatively low amounts of CO2, being the main H2 and CO at a ratio close to the unit1:

CH4 + CO2 ↔ 2CO + 2H2 These facts make DRM a more interesting source of hydrogen for the industrial production of paraffins, such as the Fischer-Tropsch reaction, while using two greenhouse gases to produce high purity syngas. DRM is generally carried out on alumina-supported Ni(Co) catalysts, where cokification side reactions take place2. These parallel reactions are a source of carbon deposition on the active sites. The coke often forms as nanotubes that block the porous matrix of the catalysts upon the progress of the reaction, ultimately impeding the access of the active sites. Research efforts have been pointing towards this direction in order to improve the overall economy of the process. Catalytic Membrane Reactors (CMR) have been proposed as an alternative to classical fixed bed reactors which suffer from early deactivation phenomena and higher operational costs due to significant pressure drops3 (which convey mass transfer limitations). Porosity could be tuned in CMR in order to limit the growth of polymeric coke species. In this work, the influence of porosity of the CMR on the selectivity (H2/CO ratio) and conversion was studied for the DRM reaction using Ni/Al2O3 catalysts. Moreover, the flow-through configuration of the CMR was studied in addition to the monolith-like configuration in order to verify the variation on performance with the flow regime and mass-transfer related parameters. According to the obtained results, the DRM reaction was efficiently carried out in the CMR. It was shown that deactivation by coke-blocking of the active sites did not occur when the majority of the catalyst was located within a thin mesoporous layer. Even if carbon formation did occur at the vicinity of the active sites confined in the mesoporous layer, no deactivation was observed as there was no evidence of nanotubes. Instead, at intermediate sections, where the pore size progressively increases, nanotubes were free to grow and were expectedly identified. This results suggested a mechanical limitation for the carbon nanotube to grow in areas where the pore size does not allow it. Permeation tests along with the calculated mass transfer-related parameters from experimental data allowed to conclude that the reaction is not diffusion-limited in the CMR. References 1. Pakhare, D., Spivey, J. Chem Soc. Rev. 2014, 43, 7813-783. 2. Fischer, F., Tropsch, H. Brennst-Chem. 1928, 3(9), 39-46. 3. Bosko, M.L., Munera, J.F., Lombardo, E.A., Cornaglia, L.M. J. Membr. Sci. 2010, 364, 17-26

SPL15


Study of the catalytic transfer hydrogenation of levulinate esters with

alcohols in the gas phase

P. Blair Vásqueza, T. Tabanellia, E. Montia, S. Albonettia, F. Cavania

a Dipartimento di Chimica Industriale ‘‘Toso Montanari’’, Università di Bologna, Risorgimento 4, 40136 Bologna, Italia


Levulinic acid (4-oxopentanoic acid, LA) is a polyfunctional molecule that is obtained from biomass. Because of its particular structure and reactivity, The United States Department of energy has classified LA as one of the top 12 building block chemicals (1). Nowadays, the most common strategy for the valorization of LA (or its esters) is the chemical reduction in order to obtain valuable chemicals such as fuel additives, solvents and other added value chemicals such as γ-valerolactone (GVL). The most common approach is the hydrogenation with molecular hydrogen (H2). This is typically done in batch systems, with high H2 pressures and employing noble metal catalysts, which makes this approach expensive and less applicable due to the extreme conditions (2). The need for an alternative approach has led to the study of catalytic transfer hydrogenation (CTH) through the Meerwein–Ponndorf–Verley (MPV) reaction with heterogenous transition metal oxide catalysts. This approach uses organic molecules, such as alcohols that are capable of acting as a hydride transfer agent (H-donor), in order to reduce a molecule that contains a carbonyl group. Among these, secondary alcohols show more marked reactivity as the carbocationic intermediate is more stable (3). Studies have reported the batch liquid-phase CTH of levulinate esters with isopropanol. The best results (in terms of GVL yield) have been obtained over ZrO2

based catalysts. (4-5). However, there are no studies in the literature that report the continuous gas-phase CTH of levulinate esters. Hence, in this study, several metal oxides (MgO, Mg/Fe/O, Mg/Ga/O, ZrO2) were tested for the gas-phase CTH of methyl levulinate (ML) at different temperatures using different alcohols as H-donor. In particular, it was decided to investigate methanol as an alternative

reagent since it is decomposed to light products (CO and H2), facilitating the purification of the products of interest, and it has already been verified to be active in the reduction of furfural in similar systems (6). With methanol, the highest GVL yield obtained (18.7%) was using ZrO2 catalyst at 300 °C reaching a conversion of ML of 64.3%. Since ZrO2 gave the best results, further studies were conducted with isopropanol as H-donor reaching a GVL yield of 82% and a conversion of 93.1%. References (1) Werpy, T. & Petersen, G. Top Value Added Chemicals from Biomass Volume I. U.S. Department of Energy: Energy Efficiency and Renewable Energy, 2004. doi:10.2172/15008859 (2) Rackemann, D. W. & Doherty, W. O. Biofuels, Bioprod. Biorefining, 2011, 5, 198–214 (3) Chia, M. & Dumesic, J. A. Chem. Commun. 2011, 47, 12233 (4) Xie, Y., Li, F., Wang, J., Wang, R., Wang, H., Liu, X. Mol. Catal. 2017, 442, 107–114 (5) Kuwahara, Y., Kaburagi, W., Osada, Y., Fujitani, T. & Yamashita, H. Catal. Today 2017, 281, 418–428 (6) Pasini, T., Lolli, A., Albonetti, S., Cavani, F. & Mella, M. J. Catal. 2014, 317, 206–219

Acknowledgements: This work was funded by Erasmus Mundus Ph.D Programme in Sustainable Industrial Chemistry- SINCHEM http://www.sinchem.eu/

Figure 1. Yield and conversion with ZrO2, reaction time 2.5 h, T=300 °C, alcohol:ML-10:1. a monoclinic phase, b commercial c reaction time 2h, d high sup. area – tetragonal phase, e i-PrOH:ML-4:1.

SPL16


Optimization of grafting SBA-15 synthesis for lignocellulosic biomass valorization

C.Pizzolittoa, M. Signorettoa, F. Menegazzoa, E. Ghedinia, G. Cerratob,

aCATMAT Lab, Department of Molecular Sciences and Nanosystems, Ca’ Foscari University Venice and INSTM RU of Venice, via Torino 155, 30172 Venezia Mestre, Italy

b Department of Chemistry, University of Turin, via Pietro Giuria, 7, 10125 Torino, Italy


Currently 80 % of fuels and 95 % of chemicals are produced by fossil sources, that despite their high efficiency, have environmental and social problems. For this reason, a bio-based resources revolution is highly expected. Biomass utilisation has gained considerable interest in this sense, for its high potentiality as a resourceful substrate both for chemicals and fuels. Nonetheless, catalysis covers great importance in the development of efficient yet sustainable processes for biomass exploitation. In this work, the attention has been focused on the valorisation of lignocellulosic biomass for the productions of bio-chemicals.1 For this study, a territorial and economically relevant 2nd generation wine wastes biomass, whose volume is 4 million tons in Italy, has been used. This waste is made up of 50-60 wt. % of water so, looking also at the greenest and most suitable reaction medium, water was used as solvent of reaction. Chemical reactions involved in this transformation are hydrolyses that are catalysed by either homogeneous or heterogeneous Brønsted acid catalysts. However, the potentiality of a heterogeneous catalyst is huge, since it avoids rig corrosion and problems of regeneration. At the same time leaching of the active acid sites and pore obstruction are possible source of deactivation, as long as mass transfer limitations to the efficiency of the process. The aim of this work is the development and optimisation of synthetic procedure for the production of heterogeneous solid acid catalysts based on SBA-15. High surface area material was used as base to guarantee a strong interaction between reagents and active sites; this point has a crucial aspect because it’s the limit of heterogeneous catalysis application in this field. In order to achieve acid properties at SBA-15 material, grafting method was used. In this sense, 3-Mercaptopropyltrimethoxysilane (MPTMS) was used as grafting agent and tree different solvents were employed for the synthesis: esane, toluene and a mixture of water and NaCl.2,3 Materials were characterised using different techniques such as N2-physisorption, FTIR and SEM. Catalytic tests were conducted in a stainless still autoclave at the temperature between 160 °C- 200 °C in autogenous pressure using glucose as model molecule. It was found that preparation methods highly affect the morphological and chemical features of the materials. The different characterization techniques allow to understand the importance of surface area, hydrothermal stability and Brønsted acid sites and allow to correlate the morphology and structural features of the catalysts with their catalytic activity and selectivity. References 1. S.S.Chen, T. Maneerung, D.C.W. Tsang, Y.S.Ok, C.Wang, Chem. Eng. J., 2017, 328, 246-273 2. C. Pirez, A. F. Lee, J. C. Manayil, C. M. A. Parlett and K. Wilson, Green Chem., 2014, 16, 4506-4510 3. G.M. Ziarani, N. Lashgari, A.Bafieri, J. Mol. Catal. A: Chem, 2015, 397, 166-191

SPL17


Microwave-Assisted preparation of Fe/Co catalysts for Fischer-Tropsch synthesis on biomass derived syngas

M. Russo, M.L. Testa, V. La Parola, G. Pantaleo, A. M. Venezia

Istituto per lo Studio dei Materiali Nanostrutturati, CNR-ISMN, Palermo, Italy

e-mail: [email protected] In recent years, considerable efforts have been done to reduce worldwide fossil fuels dependence exploiting renewable feedstock for the production of biofuels and thus reducing greenhouse gas emissions. In this context, there has been a revitalized interest for the Fischer-Tropsch synthesis (FTS) (1) applied in the valorisation of biomass for the biofuels production. In particular, improvements in the catalytic efficiency of classical Fe and Co based catalysts have been driven by the need to enhance the characteristic low H2/CO ratio of biomass-derived syngas. Under these conditions, Fe has a low FTS catalytic efficiency but is able to promote the water gas shift reaction (WGS) (2) with the result of increasing the H2 content of the reaction mixture. Cobalt shows a better catalytic activity toward medium and long chain hydrocarbons but can undergo partial deactivation/sintering at high temperature.1-3

FTS: CO + 2H2 -CH2- + H2O (1)

WGS: CO + H2O H2 + CO2 (2) According to these premises, in the present work the catalytic efficiency of mono- and bimetallic Fe/Co catalysts on the FTS on biomass-derived syngas, was investigated keeping into account the effect of the metal loadings, the different supports (SiO2, TiO2 and Al2O3) and the different reaction conditions. The materials were synthesised by a microwave assisted co-precipitation procedure and tested at atmospheric pressure in a flow reactor using different H2/CO feed ratio, temperature and flow rate. The surface and structural properties of the catalysts were investigated by means of N2 adsorption isotherms (BET), temperature programmed reduction analysis (TPR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) performed on fresh and spent materials. Preliminary results show a direct correlation between the catalytic efficiency and the nature and surface area of the support used.

50 100 150 200 250 3000

500

1000

1500

2000

2500

3000

3500

4000

4500

CH4 C2 C3 CO2

Co

nce

ntr

atio

n (

pp

m)

Time (min)

T = 275 °C = 30ml /min

T = 275 °C = 15ml /min

T = 300 °C = 15ml /min

T = 350 °C = 15ml /min

FeCo/TiO2

FTS conversion of 6%wtFe-6%wtCo/TiO2 catalyst at different indicated temperature and flow conditions.

References 1. James, O. O.; Mesubi, A. M.; Ako, T. C.; Maity, S. Fuel Process. Technol. 2010, 91, 136-144. 2. Logdberg, S.; Tristantini, D.; Borg, O.; Ilver, L.; Gevert, B.; Jaras, S.; Blekkan, E. A.; Holmen, A. Appl. Catal. B

2009, 89, 167-182. 3. Hu, J.; Yu, F.; Lu, Y. Catalyst 2012, 2, 303-326.

Acknowledgements: The Cooperation between Italy and India (Prot. No. MAE01054762017) is kindly acknowledged.

SPL18


First2run: flagship demonstration of an integrated biorefinery for dry crops sustainable exploitation towards biobased materials production

Andrea Vassoia, Tommaso Tabanelli a, Francesca Digioiab, Fabrizio Cavani a

aDipartimento di Chimica Industriale “Toso Montanari”, Università degli studi di Bologna Viale del Risorgimento, 4, 40136, Bologna

bNovamont S.p.a., Via Fauser, 8, 28100, Novara e-mail: [email protected]

The role of University of Bologna team, a partner of the Flagship First2Run project, is focused on the study of the catalytic process for the transformation of fatty esters (triglycerides) and fatty acids into shorter dicarboxylic acids, more specifically the oxidative cleavage of oleic acid (or the corresponding triglyceride), from cardoon flower, into Pelargonic acid and Azelaic acid (or the corresponding ester). These acids are industrially used as component in a series of applications such as polyamides, polyesters, cosmetics, pharmaceuticals, plasticizers, lubricants, or hydraulic fluids (Figure 1)[1]. This process is currently carried out in industry with ozone as the oxidant, which however implies the use of dangerous process conditions. Matrìca, a joint venture between Versalis and Novamont, has developed a process for the oxidative cleavage in two-steps, consisting first in an hydroperoxidation of the triglyceride to the corresponding glycol and then in the oxidative cleavage of the glycol into the shorter chain acids[2] (Figure 1). Aim of my research work will be to investigate various options for the catalytic oxidation of fatty acids and esters, by means of more sustainable oxidants and catalysts. For example, one option will be the design and implementation of a heterogeneous catalyst for the oxidative cleavage step. Fig. 1: Main reaction pathways for the cleavage of Oleic acid to Azelaic acid and Pelargonic acid. References [1] Ullmann’s Encyclopedia of Industrial Chemistry, Release, 7th Edition, Wiley-VCH, Weinheim 2010. [2] Bastioli C., Milizia T., Borsotti G., US Patent 0245995 (2008) Acknowledgements: This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 669029

SPL19


Oxidation Of Glucose To Glucaric Acid Using Supported Gold Catalysts

E.Montia, S. Solmia, C. Morrealea, T.Tabanellia, F.Cavania aDipartimento di Chimica Industriale “Toso Montanari”, Alma Mater Studiorum – Università di Bologna, Bologna,

Italy e-mail: [email protected]

Glucaric acid (GA) is one of the 12 building blocks derived from sugar biomass with higher added value and better perspective for future employments.1 GA can be synthesized by oxidation of D-Glucose (Glu) and it can be used for many purposes; for instance, it is a precursor of adipic acid, a monomer for Nylon-6,6.2 Nowadays, GA can be produced by oxidation of D-Glucose with either stoichiometric oxidants, or by means of electrochemical or biochemical synthesis. However, these processes show disadvantages from either the environmental or the economic viewpoint.3 Therefore, the study of a more sustainable process to produce GA from D-Glucose is of great scientific and practical interest.

We investigated the oxidation of D-Glucose in water solvent with oxygen, and catalysts based on supported Au nanoparticles (NPs). We prepared mono- and bi-metallic NPs supported on activated carbon (metal loading 1% wt, atomic ratio for bimetallic catalysts Au:Metal = 3:1). We tested the reactivity in a batch reactor and investigated the effect of different reaction parameters. Experiments with monometallic catalysts, prepared with different procedures, indicated that with smaller nanoparticles the undesired Gluconic acid (GO) degradation to lighter carboxylic acids prevailed over its selective oxidation to GA. After a preliminary investigation with bimetallic catalysts, the best system resulted to be AuBi/AC. Optimal reaction conditions were as follows: mild reaction temperature to limit degradation reactions (T < 60°C), need of a base to increase both Glu conversion to GO and its further oxidation to GA, precise O2:Glu and Glu:metal ratios in order to promote oxidation and limit the adsorption of organic species on catalyst surface. With a Glu:Metal:NaOH feed molar ratio equal to 500:1:1500, 5 wt% Glu initial concentration, at 60°C after 24 h of reaction, with 10 bar of O2, we achieved 31% GA selectivity, with 18% selectivity to GO and 40% to by-products, at complete conversion of the substrate.4

References

1. T. Werpy, G. Petersen: Top Value Added Chemicals from Biomass; US Department of Energy, Washington DC, 2004

2. University of York: Polyamides; The Essential Chemical Industry Online, 2013 3. H. Roper: Starch/Starke, 1990, 42, 346 4. S. Solmi, C. Morreale, F. Ospitali, S. Agnoli, F. Cavani; ChemCatChem, 2017, 9, 2797 –2806

SPL20


An in-situ Raman and reactivity study of the transformation occuring in Nb-doped vanadyl pyrophosphate catalyst

L. Setti a*, A. Caldarelli a, F. Cavani a, T. Tabanelli a, F. Puzzo a, C. Lucarelli b, C. Cortelli c, S.

Luciani c

a Dipartimento di Chimica Industriale e dei Materiali, Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy

b Dipartimento di Scienza e Alta Tecnologia, Università degli studi dell’Insubria, 22100, Como, Italy c Polynt SpA, Via E. Fermi 51, 24020 Scanzorosciate (BG), Italy

* [email protected]

The industrial production of maleic anhydride is achieved either by the selective oxidation of benzene or the selective oxidation of n-butane. The first one is the oldest process and present some disadvantages, in term of cost (n-butane: 750 €/ton; benzene: 1000 €/ton) and safety (benzene is a proven carcinogenic compound); since the 70’s n-butane has gradually been replaced benzene as reactant for the synthesis of maleic anhydride and nowadays approximately 80% of this compound is produced starting from n-butane. The major incentives of the C4 hydrocarbon are the lower cost and the lower environmental impact, that render n-butane an inexpensive and non-toxic feedstock. As show in Figure 1, the reaction is catalyzed by V/P/O based catalysts, namely the vanadyl pyrophosphate (VPP), with formula (VO)2P2O7.

Figure 1. Selective oxidation of n-butane to maleic anhydride.

Various structural and morphological characteristics affect the catalytic behavior of the V/P/O system, but the most important one is the presence of a slight excess P with respect to the stoichiometric amount required for the vanadyl pyrophosphate formation. In this regard, it has recently been reported that the key factor to obtain a moderately active but highly selective catalyst is the in-situ generation, under reaction conditions, of a discrete amounts of -VOPO4 on the vanadyl pyrophosphate surface, and that the generation of this V5+ phosphate is favoured in the presence of the P excess1,2. In order to further improve the catalytic performance of the industrial catalyst, the vanadyl pyrophosphate has been doped with controlled amounts of a Nb5+ compound, precursor for the generation of either a Nb or a mixed Nb/V5+ phosphate. The role and the amount of Nb was investigated by means of both reactivity experiments and in-situ Raman spectroscopy. It was found that the promoting effect shown by Nb occurred already for a very low amount of it, i.e., for a V/Nb atomic ratio as high as 150. It was found that a moderate amount of Nb may favour, under specific conditions, the generation of a discrete amount of the desired -VOPO4 compound, developing the optimal V5+/V4+ on the surface, and its performance was improved over that of the undoped vanadyl phyrophosphate 3. References:

(1) Cavani, F.; Luciani, S.; Esposti, E. D.; Cortelli, C.; Leanza, R. Chem. - A Eur. J. 2010, 16 (5), 1646–1655. (2) Cavani, F.; De Santi, D.; Luciani, S.; Löfberg, A.; Bordes-Richard, E.; Cortelli, C.; Leanza, R. Appl. Catal. A

Gen. 2010, 376 (1), 66–75. (3) Caldarelli, A.; Bañares, M. A.; Cortelli, C.; Luciani, S.; Cavani, F. Catal. Sci. Technol. 2014, 4 (2), 419–427. Acknowledgements: This work was funded by Polynt SpA.

SPL21


A one step transformation of furfural into 2-butyl-furfuryl-ether. N. Scotti, F. Zaccheria, V. Pappalardo, R. Psaro, N. Ravasio

CNR ISTM, via C. Golgi 19, 20133 Milano e-mail: [email protected]

Furfural (FAL) can be obtained very easily from xylan-type hemicelluloses such as those present in soft woods and straw and it is a very valuable platform molecule for the synthesis of both fuels and chemicals.1 One of the most important product of furfural processing is furfuryl alcohol (FOL), that is an important intermediate in fine chemicals and polymer industry and it is industrially obtained by selective hydrogenation with copper-chromite catalysts and H2. In turn, FOL can be converted to ethyl levulinate by ethanolysis in the presence of homogeneous or heterogeneous acids, while etherification with another alcohol has rarely been reported. During our work on hydrogen transfer reaction from 2-butanol to furfural we found that Zirconia and allumina gave excellent selectivity to FOL. In particular a high surface zirconia allowed to obtain quantitative transformation of FAL to FOL in 2,5 h at 140°C.

O O O OHO OZrO2SiO2-ZrO2

OHOH

100%64%

Table 1. Transfer hydrogenation of furfural with n-BuOH at 140°C

catalyst SA (m2/g) t (h) Conv (%) Sel FOL(%) Sel BFE (%) Al2O3 140 1 51 92 -

“ “ 5 89 93 - ZrO2 358 1 81 100 -

“ “ 2.5 100 100 - SiO2-ZrO2 304 1 56 12 88

“ 3 79 7 81 However, the use of a 5% ZrO2 on silica as catalyst gave butyl-furfuryl-ether (BFE) as the major product. This catalyst already showed a well-defined Lewis acid character and proved to be very active in the esterification of fatty acids with polyols owing to its resistance to the water formed.2 In the one pot reaction of furfural its behavior is very similar to the one reported for a pure Lewis acid as Sn-Beta that gave a 58% yield in the ether after 5 hours at 120°C.3 References

1. Mariscal R., Maireles-Torres P., M. Ojeda M., López Granados M., Energy Environ. Sci. 2016, 9, 1144–1189. 2. Zaccheria F., Mariani M., Psaro R., Bondioli P., Ravasio N. Appl.Catal. B: Envir. 2016, 181, 581–586 3. Antunes M. M., Valente A.A. et al., J. Catalysis 2015, 329, 522-537

Acknowledgements: COST Action FP1306 LignoVal “Valorisation of lignocellulosic biomass side streams for sustainable production of chemicals, materials & fuels using low environmental impact technologies” is acknowledged for support

SPL22


Levulinic acid esterification kinetics with ethanol in the presence of Amberlyst-15

C. Rossanoa, V. Russoa, R. Turcoa, R. Vitielloa, T. Salmib, M. Di Serioa aUniversità degli Studi di Napoli Federico II, Dipartimento di Scienze Chimiche. IT-80126 Napoli.

bÅbo Akademi University, Laboratory of Industrial Chemistry and Reaction Engineering, FI-20540 Turku/Åbo. e-mail: [email protected]

Levulinic acid (LA) has been recognized by the U.S. Department of Energy as one of the top biomass-derived platform molecules, due to its reactivity and because it can be produced at relatively low cost from lignocellulose waste. Levulinic acid esters may find an application as alternative green solvent, polymer plasticizers and fragrances [1]. LA esterification with alcohols is typically acid-catalyzed by homogeneous catalysts (i.e. sulfuric acid, phosphoric acid). Although this approach remains the most frequently utilized, a variety of heterogeneous acid catalysts have been used since recent times (i.e. zeolites, sulfated metal oxides, silica) [2]. Among the catalyst mentioned, Amberlyst-15 showed a remarkable high yield of ethyl levulinate. This behavior is due to the acidity provided by SO3H functional groups. In the present work, the kinetics of the levulinic acid esterification with ethanol in the presence of Amberlyst-15 was investigated. Experiments were performed by varying different operative conditions, i.e. stirring rate, temperature, catalyst loading and reactants ratio. As an example, the effect of temperature is displayed in Figure 1.

0 1 2 3 4 5 6 7 80

20

40

60

80

100

Lev

ulin

ic a

cid

co

nve

rsio

n [

%]

t [h]

T = 50°C T = 70°C T = 90°C

Figure 1 – Temperature effect on the levulinic acid conversion. Experiments performed at 600 rpm,

levulinic acid/ethanol 5:1 mol/mol, 5bar N2, 2.5wt.% Amberlyst-15. The collected experimental data were interpreted with reliable models taking into account both the chemical and mass transfer phenomena involved in the reaction network, such as external and internal mass-transfer limitations. The mixed PDE/DAE systems given by the mass balance equations, Eq. 1 were solved with advanced numerical techniques.

N

kk

siss

ieffsi rx

Cx

xx

D

t

C

1

,,,

(1)

The results can be considered as good starting point for the optimization of continuous reactors. References:

1. Trombettoni V., Bianchi L., Zupanic A., Porciello A., Cuomo M., Piermatti O., Marrocchi A., Vaccaro L. Efficient catalytic upgrading of levulinic acid into alkyl levulinates by resin-supported acids and flow reactors. Catalyst 2017, 7, 235.

2. Ramli N.A.S., Zaharudin N. H., Amin N.A.S. Esterification of renewable levulinic acid to levulinate esters using amberlyst-15 as a solid acid catalyst. Journal Teknologi 2017, 79:1, 137–142.

SPL23


Comparison of kinetic models in methanol production from hydrogenation of pure CO2

Grazia Leonzioa, Pier Ugo Foscoloa

aDepartment of Industrial and Information Engineering and Economics, University of L'Aquila, Via Giovanni Gronchi 18, 67100 L'Aquila, Italy;


Methanol is an important building block for chemical syntheses: the current world demand is over 80 Mt (year 2016) and the outlook is that its production will be about 100 Mt in 2020 [1]. Methanol is produced mainly by a synthesis gas mixture over Cu/ZnO/Al2O3 catalysts at 15 to 55 bar total pressure and at a temperature between 220 and 280 °C. However, in order to reduce carbon dioxide emissions, it is possible to produce methanol by pure CO2 and H2. Pilot and commercial plants for methanol synthesis using only CO2 as a carbon source have already been launched [2, 3]. As a consequence of the industrial importance of methanol, numerous kinetic models already exist to describe the reaction. Generally, when syngas is used as feeding stream Van den Bussche and Froment [4] kinetic is used. It is important to set up kinetic equations for CO2 hydrogenation in order to develop a high-efficiency reactor for methanol synthesis in this case. For these consideration, Kubota et al. [5] developed their own kinetic model. In this research, a comparison between Van den Bussche and Froment [4] and Kubota et al. [5] kinetic model is developed using the data of an industrial methanol reactor [6]. A model of the reactor is developed to this purpose in MATLAB software. The industrial methanol reactor is a Lurgi type methanol synthesis reactor: a shell-and-tube configuration with catalyst packed in tubes and boiling water, the coolant, is circulated in the shell side. The feeding stream is composed by pure carbon dioxide and hydrogen, in stochiometric ratio. Results show that no difference are present between the two considered models, as shown in figure 1 where the methanol and carbon dioxide molar fraction profile versus the weight of catalyst are reported.

Figure 1 Profile of MeOH and CO2 concentration inside the reactor according Van den Bussche and Froment [4] and Kubota et al. [5] kinetic models References

1. Iaquaniello, G., Bioresource Technology, 2017, 243, 613-619. 2. Mitsui Chemicals, Annual report 2010. 3. Carbon Recycling International Website, http://www.carbonrecycling.is(accessed on 29.10.15). 4. Van Den Bussche K.M., Journal of Catalyst, 1996, 161, 1-10. 5. Kubota, T., Applied Inorganic Chemistry, 2001, 15, 121-126. 6. Yusup, S., IJRRAS, 2010, 5, 213-222.

Acknowledgements: This work was funded by University of L’Aquila

Tube number 850Tube length 1.5 m Tube ID diameter 0.0445 m Catalyst density 1100 kg/m3 Molar feeding rate 100 mol/s CO2:H2 1:3Inlet pressure 55 bar Inlet temperature 225 °C GHSV 0.2 m3/hkg

Table 1 Reactor operating conditions

SPL24


Hydroxyapatite materials: from remediation of heavy metal pollution to new catalytic applications

M. Ferri, S. Campisi, A. Gervasini

a Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi, 19 20133 Milano (Italy) e-mail: [email protected]

Among all the calcium phospates, hydroxyapatite (HAP, Ca10(PO4)6(OH)2) has proven through the years to be a versatile material, able to play a role in different fields of the applied science, from medical engineering[1] to pollution remediation[2]. In environmental applications, as solid adsorbent, HAP as gained attention because of its unique characteristics of chemical stability, low cost, large availability, and water insolubility. HAP has proven its ability to permanently immobilize polluting (or toxic) metallic cations, with interesting yield of removal from aqueous phase in respect to the most known adsorbents[2-3]. Previous and actual studies, conducted in our laboratories, confirmed the massive and stable immobilization of several heavy metal cations, such as Cu, Pb, Cr, among others, on different HAPs[4].

HAP has even found a role in catalysis because its easy functonalization[5]. Different metallic species of catalytic interest (Cu, Co, Mn, and others) can be deposited on the HAP surface with assured uniform dispersion of the metallic centers. Such catalytic materials show a double functionality; acid-basic sites typical of bare HAP are summed to the electron transfer ability and catalytic feature of the metal ions. Until now, HAP catalysts have found a modest implementation in the field of electrocatalysis, in reactions of industrial (such as ethanol oxidation[6]) and sensoring/environmental interest (sensing/degradation of organic pollutants[7]).

In view of a more sustainable industrial chemistry, this study proposes to employ HAP material at first as sorbent of polluting metallic species and then to re-use the metal-loaded-HAP as electrocatalyst. To explore this feasibility, HAP has been charged with different metals species in tests of simulated polluted water containing given concentration of metallic species (i.e., Cu, Co, and Ni) and then the metal-loaded-HAP has been tested as electrocatalyst for glucose to gluconolactone oxidation, a model reaction of carbohydrates oxidation. Electrocatalytic effect, activity and robustness of such materials have been evaluated. Electrochemical testing (principally, cyclovoltammetric and chronoamperometric analyses) of electrodes modified with the electrocatalysts permitted to estimate the catalytic contribution of the materials to the reaction; yield and selectivity of the electrocatalysts have been also investigated. Comparison with more conventional catalysts and laboratory functionalized HAPs (ad hoc impregnated/charged) have been employed in the same model redox reaction, allowing to evaluate the catalytic usefulness of the re-used HAP catalysts. References

1. J. Kolmas, S. Krukowski, A. Laskus, M. Jurkitewicz, Ceramics International, 2016, 42, 2472–2487 2. I. Mobasherpour, E. Salahi, M. Pazouki, Arabian Journal of Chemistry, 2012, 5, 439–446 3. T. Tsuchida, J. Kubo, T. Yoshioka, S. Sakuma, T. Takeguchi, W. Ueda, J. Catal., 2008, 259, 183–189 4. S. Campisi, C. Castellano, A. Gervasini, New Journal of Chemistry, 2018, 42, 4520-4530 5. A. Fihri, C. Len, R. S. Varma, A. Solhy, Coordination Chemistry Reviews, 2017, 347 48–76 6. Q. Cui, S. Chao, Z. Bai, H. Yan, K. Wang, Lin Yang, Electrochimica Acta, 2014, 132, 31–36 7. H. Yin, Y. Zhou, S. Ai, X. Liu, L. Zhu, L. Lu, Microchim Acta, 2010, 169, 87–92

Acknowledgments: This work was funded by the INAIL project 2017-2019, for the authors are grateful for the financial support.

SPL25


Heterogeneous and homogeneous catalytic approaches for the sustainable synthesis of 5-Hydroxymethylfurfural

C. Antonetti, S. Fulignati, D. Licursi, N. Boschi, A.M. Raspolli Galletti

a Chemistry and Industrial Chemistry Department, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy. e-mail: [email protected]

In recent years, global warming and diminishing fossil resources have driven society to find renewable alternatives and biomass has attracted much attention due to its potential to produce valuable compounds, biofuels and chemicals. Among biomass-derived products, 5-hydroxymethylfurfural (HMF) has been classified by the United States Department of Energy as one of the top-12 promising building blocks and it is considered a “sleeping giant” which can be further transformed into a wide variety of value-added derivatives, due to the presence of an aldehyde group, a hydroxymethyl group and a furan ring in its structure1,2. HMF can be obtained by the acid catalysed dehydration of C6 fraction of biomass, which includes monosaccharides, such as glucose and fructose, and the more complex polysaccharides as cellulose, starch and inulin. However, the majority of the current syntheses are carried out under not sustainable reaction conditions. In this scenario, the exploitation of biomass requires the development of green strategies for the synthesis of HMF and for its upgrading to valuable products. Therefore, HMF synthesis from fructose, glucose and inulin has been studied in water in the presence of heterogeneous or homogeneous catalysts, such as acid resins and metal salts, identifying reaction conditions as much sustainable as possible3. Under this perspective, in both approaches (heterogeneous and homogeneous), appreciable substrate concentration (10-30 wt%), low amount of heterogeneous or homogeneous catalyst and microwave heating have been adopted, moving towards greener reaction conditions. In particular, high HMF yield, up to 46 mol%, was ascertained in the presence of the commercial acid resin Amberlyst-70 working with a 10 wt% fructose solution at 180°C for 20 minutes adopting a high substrate/catalyst weight ratio of 803. Regarding the employment of metal salts, sulphate, chloride and nitrate of Al, Na, K, Ni and Cu showed interesting performances toward the production of HMF. In particular, copper salts, and specifically copper (II) nitrate, led, among the investigated salts, to the best results in term of HMF yield and selectivity starting from 10 wt% fructose solution, reaching HMF yield up to 54 mol% at 188 °C for 9 minutes with very low catalyst amount (3 mM). In addition, when 10 wt% glucose solution was adopted as starting material, HMF yield of 25 mol% was obtained working at 160°C for 10 minutes in the presence of Al chloride. Finally, the polysaccharide inulin was tested as starting material and for all the investigated catalysts HMF yields comparable to those reached from fructose were ascertained, thus opening the way to the direct exploitation of inulin-rich biomasses, such as chicory root and Helianthus tuberosus.

References

1. L. Hu, L. Lin, Z. Wu, S. Zhou, S. Liu, Renew. Sust. Ener. Rev. 2017, 74, 230-257. 2. I.K.M. Yu, D.C.W. Tsang, Biores. Technol. 2017, 238, 716-732. 3. C. Antonetti, A.M. Raspolli Galletti, S. Fulignati, D. Licursi, Catal. Commun. 2017, 97, 146-150.

SPL26


Mixed NbO and NbP as effective catalysts in the direct inulin conversion to 5-hydroxymethylfurfural (HMF)

S. Campisia, M. N. Catrinckb, R. F. Teófilob, V. Dal Santoc, P. Carniti a,c, A. Gervasini a,c

aUniversità Degli Studi di Milano, Dipartimento di Chimica, Milano, Italy. bUniversidade Federal de Viçosa, Chemistry Department, Viçosa, Brazil.

c CNR-Istituto di Scienze e Tecnologie Molecolari, Milano, Italy e-mail: [email protected]

5-Hydroxymethylfurfural (HMF) is a well-known biomass-derived platform molecule that can be converted into a large number of fine chemicals, polymeric materials, solvents and fuels1. Although monosaccharides (glucose or fructose) are the most commonly studied substrates for the synthesis of HMF, the direct conversion of polysaccharides (e.g. inulin, cellulose, amylose, etc.) is a more sustainable and convenient strategy for HMF production from an industrial point of view. When glucose-containing polysaccharides are used as raw-materials for HMF synthesis, three distinct acid-catalyzed actions are involved: hydrolysis of polysaccharides, isomerization of the formed glucose monomers to fructose, and cyclo-dehydration of fructose to HMF. Consequently, the control of the selectivity to HMF is the result of a delicate balance between acid site number, strength and nature (Lewis, LAS, and Brønsted, BAS). Niobium-containing solid acids, such as niobium oxide (NbO) and niobium phosphate (NbP), owing to their strong acidic properties and water-tolerance have been successfully employed as catalysts in the transformation of biomass2. Both NbO and NbP possess BAS and LAS, with NbP showing a higher ratio of BAS to LAS than NbO3. Herein, the combination4 of NbO and NbP has been investigated in the direct inulin transformation to HMF. The composition of physical mixtures of NbO and NbP has been optimized to properly modulate the acidity and then maximize the HMF yield. Three physical mixtures with NbO:NbP mass ratio of 1:3, 1:1, and 3:1 have been prepared. The sample acidity has been characterized by liquid-solid titrations carried out in a modified liquid-chromatograph (HPLC) line by basic solutions of phenylethylamine (PEA) in an apolar-aprotic solvent (intrinsic acidity) and in water-isopropanol mixture (effective acidity). The LAS and BAS nature and relevant ratios of the acid sites were determined by infrared spectroscopy (FT-IR) analysis by pyridine adsorption under dry condition and in the presence of water. In the view to optimize the catalyst(s) able to directly convert inulin to HMF, the catalytic performances (activity, selectivity and stability) in the two single-step reactions of inulin hydrolysis to fructose/glucose and of fructose/glucose dehydration to HMF were, at first, separately investigated. Catalyst deactivation, which is the most severe limitation to the high catalytic performances in these reactions, has been deeply examined by carrying out TGA analysis on the used catalysts and by evaluating the deactivation kinetics. The comparison of catalytic behavior allowed to individuate the most promising candidates for the direct conversion of inulin to HMF. Direct synthesis of HMF starting from inulin was then studied with the selected catalysts in a two-fixed-bed reactor. References

1. Van Putten, R., Van Der Waal, C., De Jong, E., Rasrendra, C.B., Heeres, H.J., De Vries, G. Chem. Rev. 2013;113, 1499-1597

2. Marzo, M., Gervasini, A., Carniti, P. Carbohyd. Res. 2012, 347, 23-31. 3. Carniti, P., Gervasini, A., Bossola, F., Dal Santo, V. Appl Catal B 2016, 193, 93-102. 4. Catrinck, M.N., Ribeiro, E.S, Monteiro, R.S., Ribas, R.M., Barbosa, M.H., Teófilo, R.F. Fuel, 2017, 210:67-74.

Acknowledgment The authors are grateful to CAPES/PDSE for providing the scholarship to Mariana Neves Catrinck (grant nº 88881.135387/2016-01)

SPL27


Synthesis of innovative materials from natural and renewable sources

A. Salvinia,b, A. Papacchinia, R. Olivaa, F. Ridia,b, M. A. Ortenzic, aDepartment of Chemistry Ugo Schiff, University of Florence, Sesto Fiorentino (FI), Italy.

bCSGI, Sesto Fiorentino (FI), Italy. cCRC Materiali Polimerici (LaMPo), Department of Chemistry, University of Milano, Milano, Italy.


In recent times, the use of biopolymers for the production of green formulations has considerably increased in many different fields, because they easily degrade to products that are not harmful for the environment and because they are obtained from natural renewable sources. On this basis, several new biopolymers and nanocomposites were synthesized from “green monomers”, obtained using saccharides as renewable feedstocks (α,α’-trehalose and D-glucose). Properly designed synthetic procedures were used to obtain copolymers with high purity and without protection/deprotection steps in agreement with the principles of green chemistry and industrial sustainability. The choice of renewable starting materials was made in accordance to the growing interest for the exploitation of lignocellulosic biomasses and the valorization of wastes recovered from food processing and agro-industries. Moreover, saccharides were chosen as starting materials for the synthesis of bio-based monomers, in order to introduce units with a structure similar to that of the cellulosic materials in the final products. This allowed to obtain new biopolymers that showed high affinity and compatibility for the cellulosic substrates, like paper or wood, and which are suitable for applications like adhesion or consolidation in the field of cultural heritage. In the last years, different kinds of polyamides with different chemical-physical characteristics according to the choice of monomers were obtained from natural raw materials. In particular, water soluble oligoamides have been obtained from derivatives of natural substances, that are biocompatible, biodegradable, cheap and with high stability, such as L-tartaric acid, α,α-trehalose and L-lysine.1,2 Recently, allyl saccharide monomers were synthesized from α,α’ trehalose or methyl α/β-D-glucopyranoside and copolymers of these allyl monomers were obtained with vinyl acetate through radical copolymerization reactions.3 Allyl α,α’-trehalose/vinyl alcohol and allyl methyl α/β-D-glucopyranoside/vinyl alcohol copolymers were obtained by hydrolysing the correspondent vinyl acetate copolymers in order to have water soluble products. All the copolymers were characterized through FT-IR, NMR, SEC and thermal properties were evaluated by DSC. Finally, several nanocomposites with core-shell structure and potential antimicrobial and antifungal activity have also been synthesized using functionalized TiO2 nanoparticles. The nanocomposites were characterized by FT-IR spectroscopy and SEM while applicative studies on cellulosic substrates were performed to test their antifungal properties.4

References

1. Oliva, R.; Albanese, F.; Cipriani, G.; Ridi, F.;, Giomi, D.; Malavolti, M.; Bernini, L.; Salvini, A. 2014. J. Polym. Res. 21(7), 1-12. (doi: 10.1007/s10965-014-0496-2)

2. Oliva, R.; Ortenzi, M.A.; Salvini, A., Papacchini, A.; Giomi, D.; RSC Adv., 2017, 7, 12054-12062. 3. Papacchini, A.; Telaretti Leggieri, M. R.; Zucchini, L.; Ortenzi, M.A.; Ridi, F.; Giomi, D.; Salvini, A. Royal

Society Open Science 2018, accepted. 4. Oliva, R., Salvini, A., Di Giulio, G., Capozzoli, L., Fioravanti, M., Giordano, C., Perito, B. J. Appl. Polym. Sci.

2015 DOI: 10.1002/app.42047 Acknowledgements: This work was funded by Ente Cassa di Risparmio di Firenze

SPL28


Synthesis and characterization of acrylate monomers used in the “Hydrophobic Alkali Swellable Emulsion (HASE)” synthesis.

R. Vitielloa, C. Rossanoa, R. Turcoa, V. Russoa, R. Tessera, I. Russo Kraussa, G. D’Erricoa, M. Di Serioa

aUniversità degli Studi di Napoli Federico II, Dipartimento di Scienze Chimiche. IT-80126 Napoli. e-mail: [email protected]

Synthetic associative acrylic monomers functionalized by oxo alcohol based hydrophobic group have been synthetized and then used in “Hydrophobic Alkali Swellable Emulsion (HASE)”. One of the features of use these associative acrylic monomers resides in that once added into the aqueous phase containing a latex and possessing an alkaline nature, they lead to a phenomenon of increased viscosity over a wide range of shearing gradients without adding a neutralization agent. This constitutes a major asset compared to the conventional HASE polymers, which thickened a medium after adding a neutralization agent to it; such an addition has not possible in the emulsion as it has, as it might increase its viscosity to a level that would make it unworkable [1]. Higher thickening efficiency is achieved by the self-associating properties of the attached hydrophobic groups to the polymer backbone. The importance of HASE polymers is due to the great market demand since they are used in a wide range of industrial applications such as viscosizers, paint formulations, cosmetics, cleaning products and coatings paper [2]. The synthesis of the associative monomers has been carried out by an esterification reaction. The reagents used are methacrylic acid, an ethoxylated alcohol and sulfuric acid to catalyze the reaction. Because the properties of the HASE polymers are certainly related to the structure and composition, several associative acrylic monomers can be synthetized changing the ethoxylated alcohol structure (i.e. number of ethoxy groups, length of alkyl chain, linear or branched chain). The characterization of associative monomers has been performed by acid-base titration and IR spectroscopy for structural information. Another aim of the present work, as mentioned above, is to use these associative monomers synthetized in HASE polymers formulation. An example of the polymeric structure is reported in Figure 1.

Figure 1 – Molecular structure of a hydrophobically modified alkali-soluble emulsion polymer. x, y, z are structural parameters. n is the number of poly(ethylene oxide).

HASE polymers have been synthetized by emulsion polymerization. In particular, have been synthetize HASE with higher molecular weight, low residual solid and with a correct value of polydispersity index. To characterize the HASE polymers have been performed rheological tests to analyze the increasing of viscosity. References:

1. US 8,697,797 B2; Apr. 15, 2014. Inventors: Jean-Marc Suau and Denis Ruhlmann. 2. A. A. Abdala, S. Amin, J. H. van Zanten, S. A. Khan, “Tracer microrheology study of a Hydrophobically

Modified Comblike Associative Polymer,” Langmuir, 31, 3944−3951, 2015.

SPL29


New Insights into the Role of the Synthesis Procedure on the Performance of Co-Based Catalysts for Ethanol Steam Reforming

I. Rossetti,a B. Bonelli,b G. Ramis,c E. Bahadori,a R. Nasi,b A. Aronne,d S. Espositoe*

aDip. Chimica, Università degli Studi di Milano, INSTM Unit Milano-Università and CNR-ISTM, via C. Golgi, 19, I-20133 Milano, Italy.

bDipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, INSTM Unit of Torino-Politecnico, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy.

cDip. di Ingegneria Civile, Chimica e Ambientale, Università degli Studi di Genova and INSTM Unit Genova, via all’Opera Pia 15A, Genova, Italy.

dDipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Piazzele Tecchio, 80 – I-80125 Napoli (Italy)

eDipartimento di Ingegneria Civile e Meccanica and INSTM Unit- Università di Cassino, Via G. Di Biasio 43, 03043 Cassino (Fr), Italy.


Co/SiO2 catalysts with two Co contents of 10 and 30 mol % were prepared and used in ethanol steam reforming.1 With the aim of tailoring the materials features by varying the synthesis parameters, two different sol-gel procedures were designed, namely a modified hydrolytic alkoxide sol-gel synthesis and a (non-ionic) surfactant assisted one. Effect of the synthesis procedure on the physico-chemical properties of the prepared catalysts is in the focus of the present investigation. The obtained Co/SiO2 catalysts were characterized by means of X-rays powder diffraction (XRPD); Diffuse Reflectance UV-Vis spectroscopy; N2 adsorption/desorption isotherms at -196°C; field emission scanning electron microscopy equipped with Energy Dispersive X-ray probe (FESEM-EDX); temperature-programmed reduction (TPR) and CO adsorption at nominal -196C° as followed by IR spectroscopy. The oxidation state of Co species within the SiO2 matrix was affected by the synthesis method. In particular, the non-ionic surfactant, acting both as pores template and as chelating agent of Co ions during the synthesis, prevented the formation of Co3O4 phase, leading to a higher dispersion, and higher temperature reducibility, of Co species, with respect to samples with same Co content synthesized without surfactant. The fine balance between Co dispersion and reducibility was the fundamental parameter governing the activity of the Co/SiO2 catalysts in terms of H2 production; CO/CO2 ratio and C balance during ethanol steam reforming.

References 1. Rossetti, I., Bonelli, B., Ramis, G., Bahadori, E., Nasi, R., Aronne, A., Esposito, S. Top. Catal. 2018,

doi.org/10.1007/s11244-018-0969-3.

SPL30


Revealing Cu Speciation in Cu-CHA zeolites with different composition by in situ spectroscopies.

S. Bordigaa*, A.Martinia,b, C. Negria, M. Signorilea, E. Borfecchiaa,c, K. Lomachenkod, G. Berliera, C. Lambertib,e.

aDepartment of Chemistry, NIS Centre and INSTM Reference Center, University of Turin, Turin, Italy. bThe Smart Materials Research Center, Southern Federal University, Rostov-on-Don, Russia

cHaldor Topsøe A/S, Haldor Topsøe Lyngby, Denmark dEuropean Synchrotron Radiation Facility, Grenoble, France

eDepartment of Physic, CrisDi Centre and INSTM Reference Center, University of Turin, Turin, Italy. Silvia [email protected]

Cu-exchanged chabazite (Cu-CHA) is currently the object of intensive research efforts to rationalize its outstanding performance in the NH3-assisted selective catalytic reduction (SCR) of NOx

1 and its recently proved activity in the direct conversion of methane to methanol (MTM).2 Cu is usually introduced into the zeolites via aqueous ion exchange, resulting in the formation of [Cu(OH)]+ and/or Cu2+ counterions. Recent works pointed out that the relative abundance of [Cu(OH)]+ and Cu2+ depends on the Cu/Al and Si/Al ratios, and proposed that only [Cu(OH)]+ can be ‘self-reduced’ to Cu+ sites during activation in inert atmosphere.3 To shed light on this aspect, which has important implications on the design and understanding of active catalysts for both SCR and MTM reactions, we prepared a large set of Cu-CHA samples with different Cu/Al and Si/Al ratios. These were characterized in situ by X ray Absorption (XAS) and FTIR of adsorbed probe molecules, to

follow Cu speciation and evolution during activation in different conditions.4,5 Use of multivariate data-modelling allowed us to access an unprecedented level of understanding in a complex multi-component catalytic system, yielding novel insights into the birth of Cu-active sites in the cages of the CHA zeolite. 4

Pictorial scheme reporting the main experimental and theoretical tools used to shed light on the structure of the active Cu sites in CHA frameworks and their reactivity towards NH3 SCR and direct conversion of methane to methanol reactions. References 1 Beale, A. M.; Gao, F.; Lezcano-Gonzalez, I.; Peden, C. H. F.; Szanyi, J. Chem Soc Rev 2015, 44, 7371-7405. 2 Wulfers M.J., Teketel, S., Ipek, B., Lobo R. F., Chem. Commun. 2015, 51, 4447-4450. 3 Paolucci, C.; Parekh, A. A.; Khurana, I.; Di Iorio, J. R.; Li, H.; Caballero, J. D. A.; Shih, A. J.; Anggara, T.; Delgass, et al. J Am Chem Soc. 2016, 138, 6028-6048; 4 Borfecchia, E.; Lomachenko, K. A.; Giordanino, F.; Falsig, H.; Beato, P.; Soldatov, A. V.; Bordiga, S.; Lamberti, C. Chem. Sci. 2015, 6, 548-563. 5. Pappas, DK; Borfecchia, E; Dyballa, M; Pankin, IA; Lomachenko, KA; Martini, A; Signorile, M; Teketel, S; Arstad, B; Berlier, G; Lamberti, C; Bordiga, S; Olsbye; Lillerud, KP; Svelle, S; Beato, P; J Am Chem Soc 2017, 139, 14961-14975.

SPL31


Amino acid-based ionic liquids for Carbon Capture and Storage V. Crocellàa, G. Latinib,c, M. Signorilea, S. Bocchinib, C. F. Pirrib,c, S. Bordigaa

a Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Torino, Italy.

b Centre for Sustainable Future Technologies CSFT@PoliTo Istituto Italiano di Tecnologia, Torino, Italy.. c Department of Applied Science and Technology, Politecnico di Torino, Torino, Italy.


Carbon dioxide (CO2) atmospheric concentration is continuously increasing and has already reached dangerous levels. In this context, the post-combustion Carbon Capture and Sequestration (CCS) is an important route to achieve a meaningful reduction in CO2 emissions.1 For this reason, the development of efficient systems for the reversible CO2 capture has gained considerable attention. Ionic Liquids (ILs), organic salts liquid at room temperature, have been emerging as solvents for CO2 absorption and have been considered as an interesting alternative to the usual aqueous amine solutions.2 In particular, choline-based ILs are “greener” with respect to the usual ILs thanks to their higher biocompatibility.3 On the basis of the well-known reactive interaction mechanism between CO2 and amines, the use of Amino Acids (AAs) as anions can improve the CO2 loading and, at the same time, decrease the environmental impact of these systems. In this work, different amino acids-based ILs with choline as cation were synthesized following a new synthetic route. After the synthesis, the mechanism of CO2 absorption inside the liquid was studied by means of a multiple reflection ATR-IR setup that allows spectra to be collected in liquid phase, varying both temperature and pressure. The interaction between CO2 and the different ILs were studied in in situ conditions following the chemical reactivity of the amino acid moieties with CO2: two main steps have been identified which leads to the formation of carbamate species and carbamic acid (see scheme).

The amino acid-based ILs have been studied as such or in solution with dimethyl sulfoxide (DMSO) to contrast their extremely high viscosity and, consequently, to overcome possible diffusion problems. This study allowed, for the first time, a real explanation of the species generated by the reactivity with CO2, understanding that the different functionalities of the amino acid moiety are able to deeply affect the CO2 uptake/release mechanism. References

1. Nanda S., Reddy S.N., Mitra S. K., Kozinski J.A., Energy Sci. Eng., 2016, 4, 99. 2. Zhang X. P, Zhang X. C., Dong H.F., Zhao Z. J., Zhang S. J., Huang Y., Energy Environ. Sci., 2012, 5, 6668. 3. Shengjuan Y., Yang Z., Ji X., Chen Y., Sun Y., Lu X., Energy Fuels, 2017, 31, 7325.

SPL32


A comparison between spin coating and dip coating as deposition techniques for high-porosity support activation towards CO catalytic combustion

R. Balzarottia, M. Ambrosettia, C. Cristianib, G. Groppia, E. Tronconia

a Laboratory of Catalysis and Catalytic Processes, Dipartimento di Energia, Politecnico di Milano, Via La Masa 34, Milano, Italy

a Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, Piazza Leonardo Da Vinci 32, Milano, Italy


The development of structured reactors is a hot topic in heterogeneous catalysis, as it represents one of the most promising solutions to overcome intrinsic limitations of traditional packed-bed reactors. Despite many efforts has been spent to investigate the process of active phase deposition on a wide variety of structured supports (i.e. honeycomb monoliths, foams and meshed wires [1]), a complete understanding of the activation process for supports with high surface area is yet to be achieved. Despite the great potential of these supports, which may enable the design of compact reactors [2], only few works are present reporting details about active phase depositions onto cellular supports with more than 100 PPI [3]. In this work, spin coating was used for washcoat deposition on high porosity open cell foams, as an alternative to conventional dip-blowing techniques. The slurry coating procedure was used to make FeCrAl foams of different cell sizes (i.e. 1200 and 580 μm) catalytically active, using palladium supported over cerium oxide. After dip-coating, samples were spin coated in order to manage the washcoat load and results were compared to conventional dip-coated samples. Optical microscope characterization (Fig. 1-a/b) shows that the occurrence of pore clogging is manifest at the borders of dip-coated samples, while the use of spin coating results in open pores on the whole frontal area of the sample.

Figure 1 - Optical microscope analysis of dip coated (a) and spin coated (b) samples with 580 μm cell size; catalytic conversion as a function of temperature at 3 SLM (squares) and at 6 SLM (circles) for dip coated (red) and spin coated (blue) samples (c).

Samples were tested for the CO catalytic combustion process in air using a tubular lab-scale reactor. As reported in Fig.1-c, samples prepared by spin coating display higher conversions in the external mass transfer controlled regime with respect to dip-coated ones. The higher conversion associated with foams activated with spin coating can be justified by an higher active surface, due to a better and more complete coverage of the surface as, in the diffusive regime, conversion is influenced by the catalytic exposed area and the fluid-dynamic conditions.

References 1. Meille, V. Appl. Catal. A Gen. 2006, 315, 1-17. 2. Gokon, N. et al. Int. J. Hydrogen Energy. 2011, 36, 2014–2028 3. Zhou, W. et al. Fuel. 2017, 191, 46–53

Acknowledgements: This project has received funding from the European Research Council under Grant Agreement no. 694910 (INTENT).

SPL33


Multipolymer Electrolyte Membranes Designed by Oxygen Inhibited UV-Induced Polymerization for Integrated Energy Conversion and Storage

Devices

A. Scaliaa, A. Lambertia, E. Tressoa, C. Gerbaldia, F. Bellaa aDepartment of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino

(Italy) e-mail: [email protected]

The increasing energy request in off-grid conditions is forcing the scientific and industrial community to explore the feasibility of integrated photovoltaic (PV)-based harvesting storage devices. Among the third generation PV technologies a valuable compromise between cost, relatively high efficiency and stability is represented by the so called dye-sensitized solar cells (DSSCs), that improve their conversion efficiency under low illumination conditions [1]. Regarding the storage section, electrical double layer capacitors (EDLCs) are reaching wide attention due to their simple configuration, long cycle life and high power density [2]. Here we present a novel polymer-based platform applied for the fabrication of an innovative two-electrodes self-powered device integrating energy harvesting and storage sections. For the energy harvesting section, one side of the polymeric layer is adapted to enable iodide/triiodide diffusion in a DSSC, while the other side empowers sodium/chloride ions diffusion and is employed for on-board charge storage in an EDLC. The measured photo-electrical conversion and storage total efficiency is of 3.72% during photo-charge, which is among the highest values reported in literature for a DSSC-EDLC harvesting-storage device.

Fig. 1 3D Sketch representation of the integrated HS device, showing the different components and the smart multifunctional polymer electrolyte membrane.

1. Scalia, A.; Bella, F.; Lamberti, A.; Bianco, S.; Gerbaldi, C.; Tresso, E.; Pirri, C.F. J. Power Sources 2017, 359, 311-321.

2. Scalia, A.; Varzi, A.; Lamberti, A.; Tresso, E.; Jeong, S.; Jacob, T.; Passerini, S. Sustain. Energy Fuels 2018, 2, 968-977.

SPL34


Intensification of environmental catalytic processes with open-cell foams and periodic open cellular structures catalyst supports

M.Ambrosetti a, M.Bracconia, M.Maestria,G.Groppia,E.Tronconia aLaboratory of Catalysis and Catalytic Processes, Dipartimento di Energia, Politecnico di Milano, Milano,Italy

[email protected]

A central aspect in environmental processes is the tradeoff between diffusional mass transfer and pressure drops. Honeycombs are considered state-of-the-art supports because they exibith an ideal tradeoff between conversion and pressure losses thanks to the segregated and laminar flow-field [1]. An alternative solution is represented by cellular materials like open-cell foams and Periodic Open Cellular Structures – POCS. The characteristic geometry of these structures enables both high surface area and void fraction. Despite the high interest towards new structured catalyst supports, adequate engineering correlations for the description of gas-to-solid mass transfer and pressure drops are still missing. In this work, we present the results of a combined numerical (CFD) and experimental investigation of the transport properties of open-cell foams and POCS. We perfomed pressure drops measurement in both structures along with numerical simulations. Moreover, mass transfer tests running CO oxidation in the external mass transfer limited regime are employed to validate the numerical simulations in external mass transfer control. Correlations able to accuratly describe the performances of a wide set of samples with different geometrical properties and flow conditions are derived. Open-cell foams, due to their random geometry shows higher mass transfer rates than POCS at the cost of higher pressure drops [2].

1 10 100 10000.1

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100

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/3 (

-)

Exp & CDF Foams Correlation Foams Exp POCS Correlation POCS

2S

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-)

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it in

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Giani et al. [1] introduced a dimensionless merit index able to describe the tradeoff between conversion in diffusion limited regime and pressure drops. With the derived correlations, we compared the merit index of state of the art square channel honeycombs (HC in Fig. 1c ) with the one calculated for these innovative structures. This comparison shows that in a limited range of Reynolds numbers these structures are able to outperform current technologies.

References [1] L. Giani et al., Ind. Eng. Chem. Res. 2005 44 4993–5002. [2] M. Klumpp et al., Chem. Eng. J., 2014. 242 364–378.

Acknowledgements: This project has received funding from the European Research Council under Grant Agreement no. 694910 (INTENT). The activity on pressure drops of foams was performed in cooperation with Dr. X. Fan - University of Manchester.

Fig 1 c) Merit index for different supports Fig 1 a) Mass transfer correlations Fig 1 b) Pressure drops for foams

SPL35


The effect of inerts on the efficiency of Improved Explosive Device

Gianmaria Pio, Raffaela Moricone, Valerio Cozzani, Ernesto Salzano Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, Bologna (IT)

e-mail: gianmaria,[email protected]

Improvised Explosive Devices (IEDs) are an effective issue for the security of industrial and civilian infrastructures and for people safety. They are often produced by non-experts, starting from common commercial products, often following available recipes and manuals. In most cases they are ignited without proper detonator or primary explosive, due to their difficult availability. Typical of examples of IEDs are TATP (Triacetone Triperoxide) or ANFO (Ammonium Nitrate Fuel Oil) [1]. This latest is commonly adopted in mining and can be easily produced starting from fertilizer pellets and gasoline. Despite the apparent simplicity, the efficiency of IED are however strongly affected by the production methodology, by laboratory conditions and, even more, by the adoption of reactants at non-pure grade. For the specific case of ANFO, the presence of carbonates, dolomites and the low porosity of the commercial Ammonium Nitrate are indeed able to dramatically reduce the explosive efficiency. In our work, a thermal analysis (TGAQ500/DSCQ2000 from TA Instruments-Waters, operation conditions: 30-400°C, 10°C/min, 0.1MPa, initial sample weight < 2mg) of different samples containing Ammonium Nitrate (AN), Calcium Carbonate (CaCO3) and Nonane (as the Fuel) has been performed. The solid mixtures were prepared by using both reactants at the pure grade and the commercial fertilizer (BCR178, Calcium ammonium nitrate fertilizer) obtained from Sigma Aldrich. Results are reported in Table 1 in terms of decomposition energy for different samples measured in pure nitrogen. Data are given per unit mass of sample or per unit mass and mole of the main component (AN). The AN data reflects the heat of decomposition at low temperature for the coupled reactions [2]:

Besides, the heat of decomposition is affected by the addition of CaCO3 or using BCR178 instead of the pure-grade AN. The heat of evaporation of Nonane (0.339 kJ/g) should be taken into account for the mixtures with the fuel. That is essential for the definition of explosion energy of IED and should be considered when dealing with the security of critical infrastructures. Table 1. Decomposition energy per gram of sample or AN, as evaluated by thermal analysis.

Sample name Composition (%wt) ΔHd (kJ/g) ΔHd (kJ/gAN) ΔHd (kJ/molAN)AN 100 1.603 1.603 128.228 AN + Fuel (ANFO) 86 : 14 1.586 1.850 147.982 AN+ CaCO3 (CAN) 75 : 25 0.946 1.260 100.775 AN+ CaCO3+ Fuel 66 :22 : 12 1.092 1.649 131.911 BCR178 100 1.046 1.394 111.488 BCR178+ Fuel 88 : 12 1.071 1.620 129.568 References 1. Basco, A, Salzano, E. Propellants, Explosives, Pyrotechnics, 2012, 37, 724 -731. 2. Han, Z., Sachdeva, S., Papadaki, M.I, Mannan, S., Journal of Loss Prevention, 2015, 35, 307-315. Acknowledgements: the authors wish to thank Giulia Pelat for her useful contribution.

SPL36


THE EXPLOSION HAZARD OF CHEMICALS UNDER FIRE CONDITIONS

E. Danzia, E. Salzanob, L. Marmo aDip. Scienza Applicata e Tecnologia, Politecnico di Torino Torino (IT)

e-mail: [email protected] b Dip. di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via U. Terracini 28, 40131

Bologna (IT)

Chemical substances are classified under the H (hazards) and P (precautionary) statements. In particular, H2xy and H3xy indicate substances which imply physical and health hazards. However, issues are not only related to the single elements, but concern also the incompatibility of different substances, when accidentally come into contact with each other. Indeed, chemicals could enhance exothermal and explosive reactions when in contact with other materials, as reported by their Material Safety Datasheet. Furthermore, substances which are relatively safe at ambient conditions can be unstable and could enhance fire effects due to release of oxygen in air due to decomposition, or can produce explosion under thermal shock or in fire conditions. This evidence has occurred in a recent dramatic accident in the North of Italy in warehouse storing several substances, including Hydroxylamine sulphate (NH3OH)2SO4. There, a relatively weak fire, still contained inside the building and apparently affecting only a portion of the warehouse, induced a series of severe explosions, possibly related to the explosion of Hydroxylamine produced for the decomposition of the sulphate salt. The building was then totally destroyed, and the fire spread considerably. Two firemen suffered minor bursts. Three different craters (hence three detonations) were found during the investigation in situ, with different depths below ground. Degradation of sulfate is highly exothermic and explosive at temperatures higher than 170°C, which is above its melting point. Hydroxylamine generated is an unstable and hazardous element, classified as H200 (unstable explosive) and behaves similarly to traditional explosives such as TNT. Several episodes of explosion related to presence of hydroxylamine are reported among recent. According to CLP (1272/2008) no “explosive” definition is due to this substance, although several public reports indicate that at temperature above 130°C the substance decomposes with an explosive behavior. The accident occurred is the direct outcome of the inadequate management and storage procedures. Storage policy was defective for many reasons: primarily non-compatible products were stored together, large amount of strongly oxidizing substances (chlorate and perchlorates, hydroxylamine sulfate) were kept close to combustible materials (such as PEG and lignite). Detonation occurred when hydroxylamine and chlorates compounds reached their decomposition temperature and reacted explosively. Indeed, it is likely that fire irradiated and impinged the bags containing the first substance and enhance the reaction to give the first detonation, while the more powerful second explosion could have raised due to the higher reaction surface of the hydroxylamine sulfate bags, generated by the first pressure wave. This assumption could explain also the different position of the craters. References 1. U.S. Chemical Safety and Hazard Investigation Board, The Explosion at Concept Sciences: Hazards of

Hydroxylamine, Washington, DC, 2002.

SPL37


Sessione Poster

Martedì 4 Settembre


Production of bio-lubricants from non-edible oil via esterification reaction catalyzed by immobilized lipase from Candida rugosa on Fe3O4/Ag NPs

M. Sarnoa,b, M. Iulianoa aDepartment of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy. bNANO_MATES, Research Centre for Nanomaterials and Nanotechnology at the University of Salerno, University of

Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy. email: [email protected]

Lubricants act as anti-friction media and help in reducing wear of the components in contact during motion of the machine parts. Nowadays, the majority of the used lubricants are from petroleum oils1. These type of oils present serious environmental concerns due to the high contaminant and poor biodegradability2. Furthermore, the increase in the price of petroleum oil have requirement development for sustainable and eco-friendly products. Trend of use vegetable oils for production of bio-lubricant is an effective example in this concern. Compared to petroleum-derived lubricant, vegetable oil have characteristics as good viscosity index, high flash point, low volatility and good metal adherence3. The molecules that make up vegetable oils have a polar group and a long chain hydrocarbon4. These molecules have a strong affinity with metal surfaces and are oriented away from the metal surface to form a layer with excellent lubricating properties. Involvement of edible vegetable oil feedstock’s could cause eco-logical imbalances due to the cutting down of forest land for plant at ion purposes5. Therefore, non-edible plant oils are prominent for application as bio-lubricants in the diesel engine industry6 Here, we report the potential use of non-edible vegetable oil for the production of bio-lubricants using immobilized enzymatic catalyst on Fe3O4/Ag thought esterification process in presence of pentaerythritol (PE). Fe3O4/Ag nanoparticles have been synthesized in a single step7 to allow the adsorption of the lipase from Candida rugosa (CRL). Immobilized CRL lipase was tested for olive oil hydrolysis at different pH, temperature, reaction time and studied for operational stability. Finally, the new immobilized lipase nano-biocatalyst was used in a solvent free-system for the production of bio-lubricants from non-edible oil. Immobilized lipase on Fe3O4/Ag shows high enzymatic activity and stability and results less sensitive to temperature and pH changes than the native counterpart. In addition immobilized lipase shows high bio-lubricant conversion than the free counterpart and high purity. Overall the developed process is a green alternative to the existing oil derived lubricant production.

Non edible oil

1OR O O OR3

O

O

OR2O

O

Bio‐lubricant

Immobilized Candida Rugosa lipase

References

1. Ponnekanti, N., Savita, K. Renew Sust. Energ. Rev. 2012, 16, 764-774. 2. Luther, R. Ullmann’S Encycl. Ind. Chem. 2002. 3. Madankar, C. S., Dalai, A. K., Naik, S. N. Ind. Crops Prod. 2013, 44, 139–144. 4. Jain, A., Suhane, A. Adv. Eng. Appl. Sci. Int. J. 2012, 1, 23–32. 5. Atabani, A.E., Silitonga, A.S., Ong, H.C., Mahlia, T.M.I., Masjuki,H.H., Badruddin, I.A. Renew. Sustain.

Energy Rev. 2013, 18, 211–245. 6. Biresaw, G. J.Am. Oil Chem. Soc. 2006, 83, 559–566. 7. Sarno, M., Iuliano, M. Appl. Surf. Sci. 2018, 10, 3379-3383.

SPM03


Long-term stability of solution combustion synthesized Pd-based catalysts for methane combustion in presence of steam

S. Colussia, A. Tosoa, A. Trovarellia

aDipartimento Politecnico, Università di Udine, Italy. e-mail: [email protected]

Unburned CH4 emissions coming from natural gas fuelled vehicles are becoming of great concern, due to the exponential growth of NGVs in the world market. Pd-based catalysts are known to be the most active for CH4 combustion, but they suffer of severe deactivation during time-on-stream especially in the presence of steam [1]. Here we present our results on Pd-based systems (1 wt% Pd) supported on CeO2, ZrO2 and Ce-Zr prepared by solution combustion synthesis (SCS). These catalysts, that already gave very good results in transient light-off experiments [2], are now tested during time-on-stream CH4 oxidation in presence (wet) and absence (dry) of 10 vol% of water in the feed (0.5% CH4, 2% O2, 10% H2O He to balance). The activity of a reference 1 wt% Pd/Al2O3 prepared by incipient wetness impregnation is shown for comparison. Figure 1 shows the deactivation trends for all samples in dry and wet conditions at 673 K. After 24 hours in dry atmosphere the degree of deactivation is similar for all catalysts, with a slightly better behavior for 1PdCe SCS. A completely different picture appears in wet conditions. In this case there is a great difference between 1PdAl IW and the SCS catalysts, with the latter almost maintaining the original CH4 conversion.

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Figure 1: Time-on-stream methane conversion in dry (left) and wet (right) conditions for all catalysts.

CO chemisorption measurements and TEM analysis revealed indeed that on SCS samples Pd dispersion increases after the 24 hours exposure to wet reaction atmosphere. This indicates that the treatment, comparable to a hydrothermal aging, induces a re-dispersion of Pd nanoparticles similar to what reported by Habibi et al. for PdPt bimetallic particles [3]. The stability of SCS catalysts appears promising in light of their application in real exhaust atmosphere, where the presence of a significant amount of steam (~ 10-15 vol%) cannot be avoided. References

1. Gholami, M. et al. Catalysts 2015, 5, 561. 2. Colussi, S. et al. Angew. Chem. Int. Ed. 2009, 48, 8481-8484. 3. Habibi, A. et al. Appl. Catal. A 2018, 556, 129-136.

Acknowledgements: This work was funded by Ford Motor Company under University Research Program n°2014-2195R

SPM04


Effect of Pt-deposition order on Co-based Fischer-Tropsch catalysts with low and high Co-oxide dispersion

L. Fratalocchia, C.G. Viscontia, L. Liettia


The improvement of the catalyst reducibility is one of the key-aspects to design intensified FTS reactors, which can be improved with the addition of Pt in the catalyst formulation [1]. However, most of the studies available in literature are performed using ≈15-30wt.% of Co and Pt ≥0.3 wt.% [2]. Since a strong effect is observed on the catalyst reducibility upon varying the Pt/Co ratio, a more detailed understanding on the effect of low amount of Pt (≤ 0.5 wt.%) is needed. To this end, in this work we investigate the effect of the addition of 0.1 wt.% of Pt in the formulation of two different 18wt.% Co-based catalysts, which strongly differ from each other for the size of the Co3O4 crystallites (varied with and without diethylene glycol (DEG) in the Co-impregnating solution). The Pt-promotion is performed using the commonly used sequential deposition order (SDO), according to which Pt is impregnated on the catalyst after Co [2], or using the reverse sequential deposition order (RSDO), in which Pt is deposited on the support before Co. The latter was never used for the FTS. The results obtained in this work are a clear evidence that the effect of Pt on the catalysts reducibility depends both on the catalyst preparation method and order of impregnation (Pt before/after Co). In the catalysts prepared without DEG (large Co3O4 particles), do not reduce completely to metallic Co upon reduction at 400°C, and CoO particles are still present on the catalyst surface along with Co0 crystallites. Accordingly, rather large Co0 crystallites are formed. In these catalysts, Pt favors the reduction of the smallest Co3O4 crystallites as well and hence small Co0 particles are also formed. Notably, in the sample prepared with the RSDO method, Pt is more effective in the reduction of the smallest Co3O4 if compared to the sample where Pt is added after Co (SDO method). This is likely related to the stronger interaction that is established between Pt and Co when Pt is deposited before Co. Also in the case of the samples prepared with DEG (small Co3O4 particles) Pt increases the reducibility. However, in these catalysts the effect of the Pt deposition order on the catalyst reducibility seems slightly different. In fact, the sample prepared with the RSDO method exhibits a lower degree of reduction. This is likely related to the fact that these samples contain a significant fraction of highly dispersed Co3O4 particles, as a consequence of the presence of Pt that catalyzes the decomposition of cobalt nitrates in the presence of DEG during the catalyst calcination. These very small Co3O4 particles are fairly difficult to reduce and accordingly this prevents their full reduction. The effect of Pt on the catalytic activity is rather complex. In fact, it depends on a complex interplay involving catalyst reducibility, number of the Co0 sites and dimension of the Co0 aggregates. For the catalysts prepared without DEG, the activity is related to the catalyst reducibility, and hence the addition of Pt increases the catalyst activity. In these samples the average size of the Co0 centers are in a range where the reactivity of the active sites is unaffected by the particle size. At variance, in the case of the samples prepared with DEG, a more complex picture is apparent because the presence of Pt increases the catalyst reducibility and the number of the active Co0 centers, but decreases the catalysts reactivity. This is related to the fact that the presence of Pt favors the formation and the reduction of very small Co0 particles that are however characterized by lower reactivity with respect to bigger particles. In fact the Fischer-Tropsch synthesis becomes structure sensitive for Co0 crystallites smaller than 8-10 nm, and the TOF of the active sites quickly decreases even more than one order of magnitude upon varying the average crystallite size by a few nanometers. References

1. G. Jacobs, T. K. Das, Y. Zhang, J. Li, G. Racoillet, B. H. Davis, Appl. Catal. A-Gen., 2002, 233, 263-281 2. K. M. Cook, H. D. Perez, C. H. Bartholomew, W. C. Hecker, Appl. Catal. A-Gen., 2014, 482, 275-286

SPM06


Adoption of packed metal foams for the improvement of heat transfer in Fischer-Tropsch tubular reactors

L. Fratalocchia, C.G. Viscontia, G. Groppia, L. Liettia, E. Tronconia


In the last decade, the interest in the Fischer-Tropsch synthesis (FTS) has been considerably renewed in view of exploiting both associated and remote natural gas fields. The FTS is a highly exothermic reaction with a standard reaction enthalpy of -165 kJ/molCO. The heat removal from the reactor is thus a key issue for the development of an intensified FTS reactor [1]. The use of conventional packed-bed reactors (PBRs) is severely limited by heat removal causing a series of constraints which limit the performances of the catalyst. The poor heat transport properties in PBRs lead to non-isothermal operation of the reactor. This negatively affects the catalyst selectivity since the FTS product distribution results shifted to undesired light hydrocarbons, and, in the worst case, to the onset of thermal runaway. For the first time in the scientific literature, we propose herein the possibility to enhance the heat transport properties of a FTS packed bed reactor through the adoption of highly conductive open-cell metal foams packed with catalyst pellets [2]. Our data show that, thanks to the adoption of the conductive foams, the mean temperature inside the reactor can be controlled much better providing new operating windows, which are not accessible using the conventional packed-bed reactor technology. The conductive packed-foams enable in fact running the FT reaction under severe conditions (i.e. high CO conversion and large reaction heat release) with an intensified T-control. Indeed, in a crucial comparative experiment using the conventional packed-bed reactor, although it was operated under milder conditions (i.e. the catalyst volumetric density was halved with respect to the foam), thermal runaway occurred already at very low temperatures, i.e. with limited release of reaction heat. These results are a direct indication that the heat exchange is significantly enhanced thanks to the structured conductive substrate of the foam. Highly conductive packed-foams also represent an innovative solution to increase the catalyst inventory in structured tubular reactors, since the catalyst load which can be packed in the open-cell foam is much greater than the amount which can be loaded by washcoating the same foam. In this way, the productivity per reactor volume can be boosted. Furthermore, the packed-bed configuration allows exploiting the most effective heat transfer mechanisms available, i.e. conduction within the highly conductive structured substrate in the bulk of the bed and convection due to local mixing in the packed bed at the boundary between the bed and the tube wall. Accordingly, the concept of conductive packed foams may provide an effective design strategy in the case of compact tubular reactor units for strongly exothermic processes. The results obtained in this work clearly prove that the adoption of highly conductive packed-foams is an innovative strategy to boost the productivity per reactor volume of the reactions under kinetic control, while granting at the same time enhanced heat transfer performances within the reactor. Notably, the same concept can also be exploited for lab-scale kinetic studies of strongly exothermic catalytic reactions, as it enables an excellent temperature control even under severe operating conditions, which would not be otherwise accessible, thus extending the feasible range of kinetic investigations. References

1. M. E. Dry, Catal. Today, 2002, 71, 227-241 2. L. Fratalocchi, C.G. Visconti, G. Groppi, L. Lietti, E. Tronconi, Chem. Eng. J., 2018, 349, 829-837

Acknowledgements: This project has received funding from the European Research Council under Grant Agreement no. 694910 (INTENT)

SPM07


THE EFFECTS OF INTRAPARTICLE DIFFUSION PHENOMENA ON DIMETHYL ETHER DIRECT SYNTHESIS

S. Guffantia, C. G. Viscontia, G. Groppia

aPolitecnico di Milano, Dipartimento di Energia, Milano, Italy e-mail: [email protected]

Dimethyl ether (DME) is considered a valid alternative to liquefied petroleum gas (LPG) and diesel fuel. Traditionally DME is produced from syngas in a two-step process consisting in methanol synthesis followed by methanol dehydration (indirect synthesis) [1]. To improve the process efficiency, many efforts have been made in the last decades to develop the one-step direct synthesis, combining methanol (Cu/ZnO/Al2O3) and dehydration catalyst (zeolites or γ-Al2O3). The two catalysts can be either mechanically mixed or intimately coupled by producing hybrid pellets [2]. The intraparticle diffusion phenomena have a strong influence on the reaction kinetics, which in turn affects the thermal behavior of the reactor. These effects have not been deeply investigated in literature. In order to compare the two configurations, heterogeneous models of a single tube of a multi tubular fixed bed reactor for the direct DME synthesis have been developed. The models consist of i-species mass, energy and momentum 2D balances for the gas-phase, coupled with i-species mass and energy balances for the catalyst phases (one solid phase for the hybrid pellets, two solid phases for the mixed pellets) accounting for concentration gradients (1D) in isothermal pellets. A reaction scheme including methanol (MeOH) synthesis from CO2, Reverse Water Gas Shift (RWGS) and MeOH dehydration has been adopted with kinetics taken from the literature [3]. The model equations have been implemented in gPROMS® for the numerical resolution of the boundary value problem. As part of the FLEDGED project, simulations have been performed considering different feed compositions (consisting of H2, CO, CO2, CH4) obtained from biomass gasification. In the hybrid catalyst pellet (full lines), the DME synthesis reaction consumes the methanol produced by the MeOH synthesis, while WGS removes H2O produced by both MeOH and DME syntheses. This results in a synergistic effect on the conversion rate with respect to the mechanical mixture (dotted lines), where, due to intraparticle diffusion limitation, the catalyst efficiencies decrease both in the MeOH and DME catalyst pellets, because of the equilibrium approach (Fig. a). As consequence of this the DME yield is increased in the hybrid pellet configuration (Fig. b).

References 1. Azizi Z., Rezaeimanesh M., Tohidian T., Rahimpour M.R., Chem. Eng. Process. 2014, 82, 150-172. 2. Kim J.-H., Park M.J., Kim S.J., Joo O.-S., Jung K.-D., Appl. Catal., A 2004, 264, 37-41. 3. Ng K.L., Chadwick D., Toseland B.A., Chem. Eng. Sci., 1999, 54, 3587-3592. Acknowledgements: This contribution has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 727600.

SPM08


Reactivity analysis and in-situ characterization of Ru/γ-Al2O3 catalysts during CO2 methanation in the presence of CO

L. Falboa, A. Portaa, C.G. Viscontia, L. Liettia, J. Szanyib

aDepartment of Energy - Politecnico di Milano, Milano, Italy bInstitute on integrated catalysis - Pacific Northwest National Laboratory, Richland, USA


Catalytic CO2 conversion to fuels is of utmost importance to energy and environmental goals, because it produces an energy carrier by using the most abundant greenhouse gas.1 The CO2 hydrogenation to Synthetic Natural Gas (SNG) is particularly attractive because produces a fuel which is easily transportable by using existing infrastructure.2

In this work, the reactivity of Ru-based catalysts in the CO2 methanation is investigated with the focus of understanding the effect of CO presence in the feed stream. This goal was pursued by running catalyst reactivity experiments and by in-situ DRIFTS-MS surface characterizations. A commercial 0.5 wt.% Ru/Al2O3 catalyst (Aldrich, 206199), activated by H2-reduction at 350 °C, was tested in a lab-scale reactor at P=1 ata, GHSV=5 L(STP)/h/gcat, H2/C=4 v/v, P0

inert=0.01 ata. Temperature was varied from 250 to 410 °C, while the CO/CO2 inlet ratio was varied from 0 to 4. A second catalyst was prepared by impregnation of γ-Al2O3 with an aqueous Ru(NO)(NO3)3 solution (Aldrich, 373567). In-situ infrared spectra of the in-house prepared catalyst were collected during COx hydrogenation in a high temperature DRIFT cell, and the effluent gas was analyzed by a mass spectrometer. Process conditions for DRIFTS experiments were set at P=1 ata, GHSV=10 L(STP)/h/gcat, H2/C=4 v/v, P0

inert=0.9 ata, T=200-350 °C and CO/CO2=0-4 v/v. Both the catalysts grant stable performance during CO2 methanation, with high CO2 conversion and high carbon selectivity to methane (higher than 99%, with CO being the only byproduct).3

Reactivity studies show that when CO is present in the feed and the temperature is higher than 350 °C, the catalyst is stable, and the CH4 yield is even higher than in the absence of CO. However, if the temperature is below 350 °C, Ru-catalysts are deactivated at an appreciable rate. The rate of deactivation increases by increasing CO/CO2 ratio in the inlet gas stream and by decreasing the temperature, suggesting a CO self-inhibition mechanism. DRIFTS experiments show that, in the presence of CO in the feed, the CO surface coverage is higher than that observed during methanation of pure CO2. Accordingly, as the CO coverage becomes high on the Ru particles (i.e. by decreasing T or by increasing CO/CO2 ratio), the methanation becomes kinetically inhibited due to the lack of available hydrogen on the metal sites. Carboxylate and hydrocarbon species are also formed under these conditions. When CO is removed and the catalyst is exposed to H2 (or H2/CO2) at low T, hydrocarbons on Ru rapidly disappear, while carboxylates on alumina are not removed. Hence the stable oxide-bonded carboxylate species effectively block adsorption sites for CO2, thus lowering the CO2 methanation activity of the catalyst even after the removal of CO from the feed. This phenomenon, however, can be avoided by increasing the T, primarily due to the thermal decomposition of the surface blocking species. Methanation of CO/CO2 streams can be effectively carried out on Ru-based catalysts by working at temperatures high enough to avoid high CO coverage on the metal sites and to prevent the formation of surface species that effectively block CO2 adsorption sites on the support. Furthermore, by working at these process conditions and keeping constant the H2/C inlet ratio, the presence of CO can even boost CH4 yields with respect to pure CO2 methanation. References

1. Wang, X.; Shi, H.; Szanyi, J. Nat. Commun. 2017, 8, 513 2. Aresta, M.; Dibenedetto, A.; Angelini, A. Chem. Rev. 2014, 114, 1709-1742. 3. Falbo, L.; Martinelli, M.; Visconti, C.G.; Lietti, L.; Bassano, C.; Deiana, P. Appl. Catal. B Environ. 2018, 225, 354-363

SPM09


Dynamics of N2O formation/reduction during operation of model and commercial LNT catalysts.

R. Matarresea, L. Castoldia, S. Morandib, L. Liettia* aDipartimento di Energia, Politecnico di Milano, Milano, ITALY bDipartimento di Chimica, Università di Torino, Torino, ITALY

*[email protected] LNT technique is a viable approach for the removal of NOx under lean conditions for both diesel and lean gasoline fueled engines. This technology is based on a cyclic engine operation alternating between lean and rich conditions: NOx are adsorbed on the catalyst surface during lean operations, while the surface of the trap is regenerated under the fuel rich environment. The operation of LNTs reduces NOx mainly to N2 although undesired by-products like NH3 or N2O may also be generated. NH3 is not generally a concern since an ammonia Selective Catalytic Reaction (SCR) catalyst can be placed downstream of the LNT system, such as in the case of combined NOx storage and NH3-SCR catalytic systems. At variance, N2O formation, which is a highly undesired by-product in view of its very high global warming potential (nearly 300 times that of CO2), is still an open issue. This work focuses on the mechanisms involved in the formation of N2O during the cyclic operations of typical LNT catalysts. For these purposes, lean/rich cycles under isothermal conditions have been carried out over both homemade and commercial LNT catalysts investigating the role of operating conditions (e.g. temperature, reductant type and concentration, presence of CO2+H2O, length of the lean phase, presence of NO in the rich phase and presence of inert purges between the lean/rich and rich/lean transitions). Moreover, in order to clarify the picture on the pathway involved in N2O formation the reactivity of gaseous NO and of stored NOx species (i.e. nitrites and nitrates) has been studied under temperature programming. Micro-reactor and operando FT-IR spectroscopy experiments were used as complementary techniques to provide details on the pathways leading to N2O evolution. Isothermal experiments results showed that, during lean/rich cycling operation of the LNT catalysts N2O formation occurs both upon the lean/rich (primary N2O) and rich/lean (secondary N2O) transitions. The production of both primary and secondary N2O was found to decrease on increasing temperature. Moreover, when hydrogen is used as reductant primary N2O formation is significant, while secondary N2O is negligible. Besides, when a poor reductant like propylene is used, the secondary N2O production is higher than the primary one and surface intermediate species, i.e. isocyanates and CO adsorbed on Pt sites, are well detected by FT-IR. This suggests that N2O formation occurs onto partially reduced metal sites and involves undissociated NO molecules either present in the gas-phase or released from the stored NOx species. In fact, the experiments carried out under temperature programming indicated that N2O formation is enhanced by conditions that inhibit the reduction of the noble metal and hence prevent the fast dissociation of NO, i.e. low temperatures and poorly reactive reducing agents. Secondary N2O formation (rich/lean transition) involves reducing agents (e.g. NH3, isocyanates) left on the surface during the rich phase, as pointed out by FTIR experiments. These species react with NO/O2 upon the lean transitions leading to the formation of N2O (and N2). Accordingly, secondary N2O emissions are affected by several factors including temperature, catalyst composition (e.g. ability to store ammonia) and nature of reducing agent (formation of isocyanates). More recently, to get more insights on the reaction pathways occurring in the evolution of N2O, the decomposition/reduction of N2O has also been investigated over the same catalytic systems under Temperature-Programmed Reduction (TPR) experiments. References

1. Bartova S. et al. Catal. Today 2014, 231, 145-154 2. Choi, J.-S. et al. Catal. Today 2012, 184, 20-26

SPM10


Investigation of low temperature NOx adsorption on Pd-promoted zeolites by FT-IR spectroscopy and microreactor experiments

A. Portaa, L. Castoldia, R. Matarresea, S. Morandib, S. Dzwigajc, L. Liettia*

aDipartimento di Energia, Politecnico di Milano, Milano, ITALY bDipartimento di Chimica, Università di Torino, Torino, ITALY

cCNRS UMR 7197, Université Pierre et Marie Curie, Paris, FRANCE *[email protected]

In order to comply with current - and future - emission standards, the catalytic reduction of nitrogen oxides (NOx) from lean exhaust gases is essential. Currently, two main technologies are employed for this purpose: the selective catalytic reduction (SCR) and the NOx storage and reduction (NSR). Both systems are able to achieve high NOx reduction efficiencies above 200°C, while the NOx emissions at lower temperatures are still an issue. A possible solution is the use of passive NOx adsorbers (PNA), i.e. materials able to adsorb NOx at low temperatures and then thermally desorb the stored NOx once the downstream conventional catalysts reach a suitable operating temperature. In recent years, the use of metal-promoted (e.g. Pd) zeolites has been suggested for this purpose 1,2. In this study Pd-promoted zeolites (BEA, MOR, ZSM5 and FER) have been synthesized and investigated in the low-temperature NOx adsorption. The catalysts were characterized by BET, XRD, UV-Vis and XRF, while the storage capacity of the samples was investigated by NOx adsorption/TPD tests, with and without water in the feed. Furthermore, the nature of the adsorbed NOx species has been analyzed by operando FT-IR spectroscopy. Under dry conditions at 50°C all investigated zeolite frameworks store significant amounts of NOx, up to 1 mmol/gcat in the case of MOR. This has been ascribed to the capacity of the zeolite framework to promote the NO to NO2 oxidation at low temperature due to confinement effects, and to the subsequent storage of NOx from NO2 over the zeolitic support. Indeed, the presence of Pd does not seem to have a significant impact on the amounts of the stored NOx, as similar amounts have been stored both on the bare zeolites and on the Pd-promoted samples. This evidence was confirmed by FTIR spectra, indicating that NOx are mostly adsorbed on the zeolite framework as NO+ ions; some samples also evidenced the presence of nitrate ions bonded to Na+ sites that are present as impurities. Indeed, NO- species coordinated to Pdn+ ions have been detected to a much lower extent, only on promoted samples. The thermal stability of the adsorbed species was investigated with TPD tests, during which two separate desorption peaks arise on every sample: one in the 50-150°C region and a second one at higher temperatures, in the 200-400°C range. Operando FTIR tests correlated the low temperature evolution with the desorption of NO+ species, while the high temperature peak was correlated with the desorption of the more stable nitrates and Pd-NO species. In presence of water, the NOx storage capacity is strongly depressed over all investigated samples. This is probably due to the inhibiting effect of water on NO oxidation: on the basis of NO2 adsorption experiments, NO oxidation has been identified as a crucial step in the adsorption of NOx. However, significant amounts of NOx are still adsorbed on the catalysts, especially on the Pd/ZSM5 sample showing a NOx storage capacity of 60 µmol/gcat. Notably, in the presence of water Pd plays a role on the storage, as pointed out by adsorption experiments carried out over Pd-promoted samples and on the corresponding bare supports, showing that higher amounts of NOx could be stored over the Pd-doped carriers. References (1) Murata, Y.; Morita, T.; Wada, K.; Ohno, H. SAE Int. J. Fuels Lubr. 2015, 8 (2), 1–6. (2) Chen, H.-Y.; Collier, J. E.; Liu, D.; Mantarosie, L.; Durán-Martín, D.; Novák, V.; Rajaram, R. R.; Thompsett,

D. Catal. Letters 2016, 146 (9), 1706–1711.

SPM11

XX Congresso Nazionale di Catalisi XX Congresso Nazionale della Divisione di Chimica Industriale New Insights on the SCR reaction mechanism by FTIR operando

spectroscopy R. Matarrese a*, A. Lanza a, L. Lietti a, A. Beretta a, S. Alcove Claveb, J. Collierb

a Dipartimento di Energia, Politecnico di Milano, via la Masa 34, 20156 Milano Italy bJohnson Matthey Technology Center, Sonning Common, RG4 9NH, United Kingdom

*e-mail: [email protected]

Selective catalytic reduction (SCR) of NOx by ammonia is the state-of-the-art NOx emission control technology for stationary and mobile sources. The reaction mechanism over VOx/TiO2-based catalysts has been extensively investigated since the early ’90 [1,2]; it is generally agreed that the SCR reaction implies a red-ox process where ammonia adsorbed species react with NO (either from the gas phase or weakly adsorbed) leading to the formation of N2 along with the simultaneous reduction of the surface vanadium oxides. Eventually the red-ox cycle is closed upon vanadium reoxidation by O2. In a recent DFT study, Arnarson et al. [3] proposed a complete catalytic mechanism for the SCR reaction where the rate of the Standard SCR reaction is determined by H2O formation and desorption. Also, the participation of NOx adsorbed species (nitrites, nitrates) has been envisaged in the catalytic cycle. This has prompted us to further address these aspects by performing FTIR experiments under operando conditions where the adsorption and reactivity of NO/O2 has been investigated. Accordingly, experiments have been performed where the adsorption of NOx has been addressed over reduced and oxidized model V2O5/TiO2 catalysts both in the presence and in the absence of H2O. The reactivity of the adsorbed NOx species with NH3 and with NO has also been investigated.

Figure 1 shows the results obtained after 30 min of exposure to a NO/O2/He stream at 50°C over the pre-oxidized and pre-reduced sample (dry conditions). In both cases the formation of surface nitrates is observed (bands at 1240, 1285, 1500, 1580 and 1615 cm-1); notably, their surface concentration is larger on the pre-reduced sample (dotted line) than on the pre-oxidized one (solid line). This indicates that NOx adsorption is favored by the presence of oxygen vacancies. NOx adsorption is also accompanied by the formation of a negative band at 1035 cm-1 (coupled with a band at 2050 cm-1), which is associated with the perturbation of surface vanadyl species. This confirms the participation of these species in the adsorption of NOx from NO+O2. The presence of water during the NO/O2 adsorption inhibits the formation of surface nitrates, thus pointing out the role of water on the active sites.

Finally, the thermal stability and the reactivity of the adsorbed NOx species has been investigated upon heating under inert atmosphere and in the presence of NO or NH3. The presence of NO favors nitrate reduction if compared to inert atmosphere. Based on the obtained results, new insights on the SCR chemistry and mechanism could be derived. References

1. Ramis, G et al. Appl. Catal.1990, 259-278 2. Topsøe N.Y. Science, 1994, 265, 1217-9 3. Arnason, A. et al. J.Catal. 2017, 346, 188-197.

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Figure 1. FT-IR spectra of the adsorbed species arising from 30 min contact of pre-reduced (dotted) and pre-oxidized (solid) V2O5/TiO2 under NO/O2/He stream at 50°C.

SPM12


A new renewable route to acetonitrile: process design and life-cycle analysis

Antonio Tripodia, Elnaz Bahadoria, Daniele Cespib, Fabrizio Cavanic, Fabrizio Passarinic, Gianguido Ramisd, Ilenia Rossettia


b Environmental Management and Consulting (EMC) Innovation Lab S.r.l., Viale Italia 29, 47921 Rimini, Italy c Dept. of Industrial Chemistry “Toso Montanari”, University of Bologna, viale del Risorgimento 4, Bologna, Italy

d DICCA, Università degli Studi di Genova, INSTM Unit Genova, via all’Opera Pia 15A, Genova, Italy

e-mail: [email protected] The research for new routes to acetonitrile developed of catalysts active for the ammoxidation of various substrates. Among these ethanol represents a good substrate in terms of atom economy and, being renewable, in principle can improve the sustainability of the process. A fully integrated process has been designed ex novo for the production of acetonitrile from bioethanol, with 10 kg/h of acetonitrile set as unit of production for calculations. The reactants are ethanol, ammonia and air, but in the separation train, further CO2 is consumed, besides all that produced in the process. All the byproducts, mainly ammonium bicarbonate and sodium cyanide, are recovered as marketable chemicals. In principle, all the carbon atoms and 90% of the nitrogen atoms are turned into reaction products, the main loss being gaseous N2. The Aspen Plus® process simulator has been used for process design and, further, a life cycle analysis was carried out including all the stages involved in the bioacetonitrile production (from raw materials extraction up to the gate plant). The results were then compared with those achieved for the traditional fossil route (SOHIO process), showing a sensible decrease of the environmental burdens in terms of non-renewable resources and damage to ecosystems (e.g., toxicity, climate change, etc.). Finally, a simplified sensitivity analysis was carried out by substituting the starting raw material for the production of bioethanol (corn) with other materials conventionally used worldwide, such as sugar cane and wood. The latter option seems to make the system more competitive in terms of carbon neutrality, thanks to the usage of the residual lignocellulosic fraction available on the market. The basic scheme of the process is reported in the following Figure.

SPM13


Innovative catalysts for H2 conversion to SNG via CO2 methanation

L. Trudaa, A. Riccab, V. Palmac aDepartment of Industrial Engineering, University of Salerno, 84084 Fisciano (SA), Italy bDepartment of Industrial Engineering, University of Salerno, 84084 Fisciano (SA), Italy cDepartment of Industrial Engineering, University of Salerno, 84084 Fisciano (SA), Italy.


Power to Gas (PtG) process is an emerging and interesting solution for renewables intermittence problems. Such technology results very attractive since SNG could be produced from CO2 derived from fumes and H2 produced by electrolysis of water by means surplus energy, which came from renewable sources. However, the main problem of this technology is the high exotermicity of methanation reaction, so researchers’ aim is to study innovative reactor solutions able to guarantee a good thermal control, and to find more efficiency catalytic formulations. The aim of this work is to investigate new catalytic formulations at low metal content for the Sabatier reaction by stressing the role of both metal active phase and support. In order to investigate the effect of nickel on CO2 methanation reaction, 6 catalytic samples were prepared with the impregnation-precipitation method [1], by selecting a CeO2-ZrO2 solid solution as support, and varying Nickel loading from 3 wt% to 13 wt%. Moreover, the addition of Platinum (1 wt%) was investigated on selected samples, also stressing the deposition method (co-impregnation, subsequent impregnations). Experimental tests were carried out at atmospheric pressure by fixing feed ratio (H2/CO2 = 4), dilution ratio (N2/CO2 = 5) and space velocity (WHSV = Qtot/mcat = 30 NL h-1 gcat-1); reaction temperature ranged between 200°C and 500°C with an increasing rate of 2°C/min. As reported in figure 1 (a), by increasing nickel from 3 wt% to 7 wt% CO2 conversion exhibited a dramatic enhancement. Farther nickel loading increasing did not lead to relevant enhancement catalytic performances, although higher conversion could be observed for the 10 wt% nickel sample in the almost totally of investigated temperature range. The presence of a ceria-zirconia support with high oxygen storage capacity allowed activation temperature lower that the commercial catalysts based on alumina support, which have a typical activation temperature of 350 °C.

Figure 1. Effect of nickel loading (a) and platinum addition (b) on carbon dioxide conversion.

In figure 1(b) was summarized the effect of platinum addition on the nickel based catalyst. It promoted the reverse water-gas-shift reaction with the subsequent CO-methanation result in a global lower reaction rate. The reported study evidences that an optimal nickel loading maximized CO2 conversion, remarking the role of active specie dispersion in the catalyst. Platinum addition seems to reduce activation temperature of the system although the optimization of the bimetallic catalyst preparation is required. References 1. Palma, Ruocco, Meloni, Ricca, J Clean Prod. 2017, 166, 263-272.

SPM14


On the stability of bimetallic catalysts for ethanol reforming in fluidized beds

C. Ruocco, V. Palma, A. Ricca Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 83040 Fisciano (SA), ITALY


The aim of the present work is to study the application of a fluidized bed reactor for oxidative steam reforming of ethanol (OESR) over a bimetallic Pt-Ni/CeO2-SiO2 catalyst at 500°C, H2O/C2H5OH and O2/C2H5OH ratios of 4 and 0.5, respectively. In particular, the effect of cerium salt precursor (nitrate, ammonium nitrate and acetylacetonate) on catalyst activity and stability was investigated. Three catalysts were synthetized. In all cases, the support was composed of a CeO2-SiO2 mixed oxide, prepared by impregnating calcined silica gel with an aqueous solution of cerium nitrate, cerium ammonium nitrate and cerium acetylacetonate. After impregnation, the solid was filtered, dried overnight at 120°C and calcined in a muffle furnace at 600°C for 3 hours. The ceria content for all the catalysts was fixed to 30 wt%. Ni followed by Pt were deposited on the mixed oxide by the same procedure, starting from platinum chloride and nickel nitrate as salt precursors: the metals loading were Ni (10 wt%) and Pt (3 wt%), both referred to ceria mass. The samples prepared from cerium nitrate, ammonium nitrate and acetylacetonate were denoted as A, B and C, respectively. For catalytic tests in fluidized bed quartz reactor, the composition of the feed was a mixture of ethanol, water and oxygen (1:4:0.5). Experiments were performed at 500°C for almost 100 h and theweigh hourly space velocity (WHSV) was fixed to 12.3 h-1. Products gas distribution was monitored on-line by means of an FT-IR spectrophotometer coupled to ABB analyzers. The results were compared in terms of ethanol conversion, hydrogen yield and carbon formation rate. The results of stability tests, carried out at 500°C for 100 h, are shown in Figure 1 in terms of ethanol conversion (a) and hydrogen yield. Al the samples displayed a partial deactivation and ethanol was completely converted only for few hours. The initial hydrogen yield was very close to the predicted thermodynamic value (41.5%) and a gradual yield lowering was observed over the three catalysts. However, after 80 h of test, all the samples reached a plateau condition, with no more variation in selectivity. It is worthwhile noting that, for the sample C, prepared by employing acetylacetonate, the final conversion was attested to 75%, while the other two catalysts displayed a similar behavior with plateau X of almost 60%. In addition, a higher H2 yield (20%) was recorded after 100 h of test for the sample C. Carbon formation rate measured after the test on the sample C was almost 1 half (1.4ꞏ10-6 gcoke/(gcarbon in the feedꞏgcatalystꞏh)) of the values found for the catalysts A and B: the good ceria dispersion of sample C, in fact, resulted in a very reactive catalyst, which assured high reducibility, ethanol conversion and activity towards coke gasification reaction.

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Figure 1. Ethanol conversion (a) and H2 yield (b) as a function of time-on-stream; 500°C, C2H5OH:H2O:O2:N2=10:40:5:55, WHSV=12.3 h-1..

SPM15


Muconic acid and sodium muconate hydrogenation to bio-adipic acid

S. Capellia, C. L. Bianchia, L. Pratia, A. Villaa, C. Pirolaa aUniversità degli Studi di Milano, Milan, Italy


The limited fossil resources availability and the climate change are raising wide interest between the scientific researchers and the civil community. Among the several subjects, the production of bulk chemicals from renewable sources is one of the great challenge that researchers are facing. Concerning this theme, adipic acid (AdA) production from wood biomass is one of the most important topic due to the large amount of AdA consumed and the market growth, in particular for the production of polyamides (Nylon 6,6). Bio-AdA can be produced from t,t-muconic acid (MA), a metabolic intermediate of the catechol ortho-cleavage pathway.1 In nature, microorganisms displaying this pathway are quite common and they can accumulate at least 13.5 g/l of MA as sodium muconate2. The so produced sodium muconate is then converted to AdA with a heterogeneous hydrogenation chemical reaction. Using mild operating conditions (70°C and hydrogen pressure 4 bar) and commercial catalyst (Pt/AC 5% wt or Pd/AC 5% wt) in 1 hour a full conversion and a complete selectivity toward AdA is achieved3. MA coming from the fermenter needs a purification step due to the high purity grade required for the market. The purification process consists in an acidification and crystallization steps, that transform sodium muconate into muconic acid, separating this chemical from all the compounds used in the fermenter. Considering water as hydrogenation reaction media, unfortunately MA is less soluble than sodium muconate. On the basis of these considerations different hydrogenation reactions were performed varying the operating conditions both on muconic acid and sodium muconate. The results reveal a different behavior during hydrogenation reaction performed at 70°C at different hydrogen pressures. Pd/AC 5%wt commercial catalyst was used, maintaining the catalyst/substrate ratio equal to 200:1 (mol basis). The results are reported in Fig.1. Using t,t-MA than Na-muconate a higher activity and selectivity to AdA have been observed. Moreover, the effect of reaction conditions, such as reaction temperature, hydrogen pressure and catalyst amount have been investigated.

Fig.1 Conversion and AdA selectivity obtained at 70°C, 1,3 bar of hydrogen, using t,t-Ma and sodium muconate (Na-Muc) as substrate. References 1. Kaneko, A., Ishii, Y. & Kirimura, K. Chem. Lett. 2011, 40, 381–383. 2. Vardon, D.R. Franden, M.A., Johnson, C.W., Karp, E.M., Guarnieri, M.T., Linger, J.G., Salm, M.J.Strathmann, T.J., Beckham, G.T. Energy Environ. Sci. 2015, 8, 617–628. 3. Capelli, S., Rosengart, A., Villa, A., Citterio, A., Di Michele, A., Bianchi, C.L.M., Prati, L., Pirola,C. Appl. Catal. B Environ. 2017, 218, 220–229.

SPM16


Aziridine Functionalized Carbon Nanotubes as Highly Efficient Electrocatalysts for the Selective CO2 Reduction to CO

G. Tuci,a J. Filippi,a L. Luconi,a A. Rossin,a C. Pham-Huu,b F. Vizza,a G. Giambastiania

aInstitute of Chemistry of Organometallic Compounds, ICCOM-CNR, Sesto Fiorentino, Italy bInstitute of Chemistry and Processes for Energy, Environment and Health (ICPEES), UMR 7515 CNRS- University of

Strasbourg (UdS), Strasbourg Cedex 02, France e-mail: [email protected]

The constant increase of CO2 levels in the atmosphere as a result of anthropic activities is directly linked to climate changes and global warming issues.[1] Multiple approaches need to be implemented to curb with these phenomena, including carbon sequestration, electrification of the transportation sector and switching from fossil fuels to renewable energy. One of the most promising methods to mitigate CO2 impact while providing a means of mass energy storage, is the electrochemical reduction of CO2 (CO2RR) into chemicals and fuels of added value.[2] However, electrocatalysts for CO2 conversion into products such as CO, formic acid, methanol, and small hydrocarbons, still suffer of moderate productivity and/or poor selectivity. To date, Ag and Au-based electrocatalysts exhibit the best performance for the conversion of CO2 to CO, but they irremediably suffer of poor sustainability. On this ground, metal-free systems have recently emerged as highly attractive candidates to replace metal-based systems in the process. To date, relatively few examples of metal-free catalysts for CO2RR exist, most of them raising from the class of light-heterodoped carbon nanomaterials (CNMs). In particular, a series of N-doped systems have been investigated but the nature of active sites responsible for CO2RR remains highly controversial.[3] Recent findings from some of us have demonstrated how a fine tuning of the surface properties of CNMs can be conveniently achieved by chemical functionalization of their outer surface with tailored N-containing heterocycles.[4] The chemical approach allows a precise control of N-dopants in terms of N-configuration and electronic charge distribution, offering a unique tool for the comprehension of the role of specific N-functionalities in the activation of small molecules. In this contribution we report the chemical decoration of MWCNTs with NH-aziridine functionalities (MW@NAz) and their application as highly efficient and selective metal-free electrocatalysts for CO2 reduction into CO. With a Faradaic efficiency (FE) close to 90% at -1.2V (vs. Ag/AgCl/KClsat.) and productivity as high as 48 NLCOh-1gN

-1, MW@NAz ranks among the metal-free systems with the highest performance reported so far providing, at the same time, a privileged view-point on the structure-reactivity relationship of light-heterodoped CNMs and a powerful tool to the unambiguous comprehension of the underlying CO2RR mechanism.[5]

References

1. S. J. Davis, K. Caldeira, et al., Science 2010, 329, 1330. 2. A. M. Appel, et. al. Chem. Rev. 2013, 113, 6621. 3. a) X.-D. Zhou, et al. Angew. Chem. Int. Ed. 2015, 54 , 13701. b) P. M. Ajayan, et al. ACS Nano 2015, 9, 5364. 4. a) G. Tuci, G. Giambastiani et al., ACS Catal. 2013, 3, 2108; b) Chem. Mater. 2014, 26, 3460; c) Catal. Sci.

Technol. 2016, 6, 6226; d) Catal. Sci. Technol. 2017, 7, 5833. 5. G. Tuci, J. Filippi, H. Ba, A. Rossin, L. Luconi, C. Pham-Huu, F. Vizza, G. Giambastiani, submitted.

Acknowledgements: Authors thank the TRAINER project (Catalysts for Transition to Renewable Energy Future - Ref. DGPIE/MOPGA/2017-589) and Italian MIUR (PRIN 2015, Project SMARTNESS 2015K7FZLH) for financial support.

SPM17


The catalytic versatility of Ruthenium Arene Complexes with α-Aminoacidato Ligands: selected examples

Marcello Crucianelli,a Issam Abdalghani,a Lorenzo Biancalana,b,c Fabio Marchettib,c

aDepartment of Physical and Chemical Sciences, University of L'Aquila,

Via Vetoio, 67100 L'Aquila, Italy bDepartment of Chemistry and Industrial Chemistry, University of Pisa,

Via Moruzzi 13, 56124 Pisa, Italy. cCIRCC, Via Celso Ulpiani 27, 70126 Bari, Italy

e-mail: [email protected] Ruthenium(II) arene compounds, bearing a typical three leg piano stool structure, have stimulated a huge interest for their numerous catalytic and biological applications. In particular, they have been intensively investigated in the last decade as catalytic precursors for hydrogenation reactions,1 following the success encountered by the catalytic systems developed by Noyori (Figure 1a) and culminating with the Nobel Prize award.2 In addition, several Ru(II) complexes incorporating, among others, the amphiphilic 1,3,5-triaza-7-phosphaadamantane (pta) ligand (Figure 1b), or containing a bidentate ethylenediamine ligand (Figure 1c), exhibit promising anticancer properties, that have stimulated the attention on many other analogous complexes.

(d)

Figure 1. Selected Ruthenium(II) arene compounds Among the different ligands that can be coordinated to the ruthenium arene frame, naturally occurring α-amino acids represent a class of attracting compounds, in view of their easy availability and low toxicity, and the presence of a stereogenic centre, which may play some role in asymmetric reactions. Herein, the recent results we have obtained having in mind the evaluation of the versatility of either, a series of neutral Ruthenium(II) complexes containing α-aminoacidato ligands (Figure 1d) or the ionic derivative [Ru(-p-cymene)(N,O-L-serinato)(PPh3)][CF3SO3], as catalytic precursors for the transfer hydrogenation reaction of acetophenone,3 or in the NaBH4 promoted reduction of nitro compounds and, finally, in the N-methyl morpholine N-oxide mediated selective oxidation of alcohols, working either in aqueous medium or with ionic liquids, will be described. References

1. a) Wu, X.; Xiao, J. Chem. Commun., 2007, 2449–2466. b) Canivet, J.; Süss-Fink, G. Green Chem. 2007, 9, 391–397.

2. a) Noyori, R. Adv. Synth. Catal. 2003, 345, 15–32; b) Noyori, R. Angew. Chem. Int. Ed. 2002, 41, 2008–2022. 3. Biancalana, L.; Abdalghani, I.; Chiellini, F.; Zacchini, S.; Pampaloni, G.; Crucianelli, M.; Marchetti, F. Eur. J.

Inorg. Chem., DOI: 10.1002/ejic.201800284. Acknowledgements: The University of Pisa (PRA_2017_25, “composti di metalli di transizione come possibili agenti antitumorali”) and University of L'Aquila are gratefully acknowledged for financial support. I. A. thanks the Phoenix Study Programme (PX14DF0786 code) for his PhD scholarship.

SPM18


Valorization of clean biogas to syngas

N. Schiarolia, C. Lucarellib, G. Fornasaria, F. Passarinia, M. Volantia

aDipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy.

bDipartimento di Scienza e Alta Tecnologia,Università dell’Insubria, via Valleggio 9, 22100 Como. email: [email protected]

The depletion of world fossil fuels is pushing the scientific research to investigate new alternative energy sources. In this context, “clean biogas” (CB) may represent the main candidate to replace the natural gas in the developing market for renewable energy and chemicals. Currently, this mixture is burned to produce energy in internal combustion engines, which are not efficient enough to exploit its energetic content and a search for more valuable applications of CB is desirable. Between the possible reforming processes, Dry Reforming (DR) appears the best option though the requirement of high temperatures and rapid deactivation of the catalyst due to high carbon formation rate. Another option may be represented by the so called “Steam Reforming/Dry Reforming” (SR/DR), a combination of the two reforming reactions in one-step process. This study has been focused on the development of Ni-based catalysts for the valorization of CB (equimolar mixture of CH4 and CO2). The attention has been focused on the influence of the support basicity and of small percentages of Rh on the catalyst activity/stability. The catalysts were deeply characterized before and after reaction, using XRD, BET, RAMAN, TEM, TPR/O, TPD and TG analyses. The effective convenience in the use of CB instead of natural gas to produce Hydrogen or Syngas has been studied by LCA. The effect of Rh on NiMgAlX_RhY catalysts was deeply investigated. The activity tests (Fig.s 1a and b) showed that the Ni-based catalyst performances are strictly related to the Rh content. Increasing the amount of noble metal, the CB conversion increased considerably until a plateau was reached when the NiMgAl4_Rh0.50 and NiMgAl4_Rh1.40 catalysts showed the same catalytic activities. The study on the influence of the support basicity on the catalyst properties was performed by increasing the MgO content in the NiMgAlX_Rh05 catalysts, changing the M2+/M3+ ratio to a value of 2, 3 or 4. It was found that the formation of an increasing amount of NiO/MgO solid solution in the calcined catalysts lead to stronger interaction between the support and the active phase. The H2-TPR analysis showed that the NiO reduction temperature increased with the M2+/M3+ ratio up to 900 °C in the case of NiMgAl4_Rh05 sample. This catalyst showed higher activity and stability with the time-on-stream and the TEM images of the catalysts before and after reaction showed that also the sintering process of the Ni0 particles was suppressed.

Fig. 1: a) CO2 conversion and b) CH4 conversion of the catalysts in different conditions. The first test was repeated at the end of the cycle to evaluate the catalyst deactivation (on the right).

a) b)

SPM19


How water selective membrane affects the catalytic behaviour of acid

catalysts during esterification reaction for biodiesel synthesis

C.Cannilla, G. Bonura, F. Costa, F. Frusteri

CNR-ITAE, Istituto di Tecnologie Avanzate per l’Energia “Nicola Giordano” e-mail: [email protected]

It is well know that the esterification reaction of fatty acid for the production of biofuels, using heterogenous catalysts, is negatively influenced by the formation of water. In fact, water, in addition to preventing total oil conversions, due to strictly thermodynamic limits (reaction to equilibrium) plays an important role in the competitive absorption on acid sites with consequent deactivation of the catalyst [1]. For this reason, it is of great interest, from a practical point of view, to study separation processes able to eliminate the water formed during the reaction [2]. The esterification of oleic acid (OlAc) can represent well the biodiesel production being present in most of oil crops, and methanol, ethanol and butanol are the most employed alcohols. Anyhow the EtOH biological nature and its extra carbon atom, which slightly increases the heat content and the cetane number of the esters, make ethyl esters more interesting than methyl esters. On this account, in this study, the benefits that can be obtained in OlAc esterification in presence of both methanol and ethanol by using a batch reactor coupled with a membrane separation system in pervaporation configuration is clearly demonstrated. Particularly, by optimizing the reaction conditions, total oleic acid conversion can be achieved by continuously subtracting the water from the reaction medium, even in the presence of zeolite catalysts, whose activity is lower than that of acid resins, as Amberlyst-15. The use of the ethanol instead of methanol favors the water selective permeation of the water through the membrane with consequent positive effects. A fundamental parameter to improve water permeation through the membrane is the recirculation rate of the gas phase, to ensure a turbulent

flow regime. The best results with both methanol and ethanol have been achieved at 80°C with a low membrane surface (Sm) and gas volume (Vg) ratio (0.20 cm-1), low acid/ethanol molar ratio (2/1 and 1/1 respectively), using A-15. Interesting results with zeolite were obtained slightly increasing the temperature at 100°C.

Fig. 1 Esterification reaction of OlAc with MeOH and A-15 in presence of the permeoselective membrane: TR=80°C; RMeOH/OlAc = 2 mol/mol; Rcat/OlAc. = 5 wt.%. Influence of Sm/Vg ratio.

References

1. Park, Y.M., Kim, D.K., Lee, J.S., Bioresour. Technol. 2010, 101, S62-S65. 2. Cannilla, C., Bonura, G., Frusteri, F., Catalysts 2017, 7, 187.

Acknowledgements: This work was funded by the Bilateral Agreement of Scientific and Technological Cooperation CNR-MTA/HAS.

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SPM20


Integration of particulate filter and selective catalytic reduction for diesel exhaust treatment

F. Martinovica, S. Bensaida, F.A. Deorsolaa, R. Pironea

aPolitecnico di Torino, DISAT, Torino, Italy. e-mail: [email protected]

Exhaust gas treatment devices for diesel engines are usually complex, expensive and large. One way to reduce size, cost and improve performance is to integrate several functionalities on a single device such as the combination of SCR on DPF (SCRoF). The largest disadvantage of current commercial systems is that soot oxidation by NO2 is inhibited by NO2 consumption in the SCR reaction [1,2,3]. The aim has been to construct a reactor configuration where the SCoF has both soot oxidation and SCR functions. This is achieved by placing the soot oxidation catalyst on top, while the SCR catalyst on the bottom (Fig.1). The challenge was to find a catalyst good for soot oxidation while avoiding ammonia oxidation. Catalysts were investigated in a laboratory scale tubular reactor with powdered catalyst mixed with soot in loose contact and synthetic reaction mixture constituted of 500 ppm NH3, 250 ppm NO, 250 ppm NO2, 4% O2, heated by a rate of 2°C/min. Dual-layer was achieved by separating the two catalyst by quartz wool. It was found that alkali carbonates supported on neutral or basic oxide support (e.g. MgO, MgAlO, ZrO2, etc.) were highly active for soot oxidation however inactive for ammonia activation (Fig.2). By using 10% K2CO3/CeO2-ZrO2 as the top layer, maximum soot oxidation temperature was lowered to 380ºC (Fig.2). This is compared to the case of Fe-ZSM5 catalyst only, where it is non-catalytic and inhibited by NO2 consumption (Fig.2). At the same time, by using Fe-ZSM5 as SCR catalyst, NOx conversion and selectivity above 80% was achieved in the whole range in both cases, indicating that soot oxidation has no significant effect on SCR activity (full lines on Fig.2).

Fig.2. TPO profiles of soot oxidation on Fe-ZSM5 and in dual layer configuration (left) and conversion profiles of NOx and NH3 (right).

References: 1. Marchitti, F. Catal. Today 2016, 267, 110-118. 2. Rappé, K. Ind. Eng. Chem. Res. 2014, 53, 17547–17557. 3. Karamitros, D. Chem. Eng. Sci. 2017, 173, 514-524. Acknowledgements: This work was funded by SINCHEM Grant. SINCHEM is a Joint Doctorate programme selected under the Erasmus Mundus Action 1 Programme (FPA 2013-0037).

Fig.1. Proposed reactor configuration

SPM21


Inorganic membrane silanization for the preparation of hydrophobic macroporous separation interfaces or microporous silica membranes

M. Paglieroa, A. Bottino a, C. Costaa, A. Comite a amembrane&membrane, Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Genoa,

Italy e-mail: [email protected]

Silica membranes are usually produced by the sol-gel technique which needs complex silica sol preparation and a very careful control of the deposition conditions in order to obtain a homogeneous surface with the desired porosity [1]. Moreover, ceramic membranes due to the presence of hydroxyl groups exhibit a hydrophilic character, which hinders their application as phase interface in membrane contactors and membrane reactors working with an aqueous phase. In this work the silanization technique has been applied to commercial ceramic membranes in order to easily prepare either hydrophobic inorganic membranes (e.g. for membrane distillation) or silica layered membranes (for gas separation or catalyst supports). Macroporous and mesoporous tubular commercial alumina membranes have been functionalized using methyltrichlorosilane in anhydrous ethyl acetate. The surface hydroxyl groups of alumina reacting with the organo-silane made the inorganic membrane switch from a hydrophilic to a hydrophobic behaviour [2]. The contact angle was measured before and after the silanization and while the untreated membranes absorbed the water drop in few seconds, the treated ones showed a contact angle of about 120°. The effects of the nominal pore size and of methyltrichlorosilane concentration have been investigated by various techniques such as water vapour transport rate, gas permeation, physisorption, FT-IR and FE-SEM. The silanization treatment had a little influence on the permeance and pore texture of macroporous (from 200 nm to 30 nm) membranes, while it strongly affected the pore size of 5 nm alumina membranes by reducing their mesopores to micropores. The hydrophobic macroporous membranes were tested in a lab-scale vacuum membrane distillation plant showing good performances both in terms of water flux and salts rejection. The effect of a calcination post-treatment was studied showing that the hydrophobic behaviour remained unchanged until about 400°C, while by further increasing the temperature the membrane surface returned totally hydrophilic. On the surface of the smallest pore size membrane a thin microporous silica layer on the surface of the alumina support was formed. The microporous silica-alumina membranes were tested for gas separation properties on streams containing H2O, N2, H2 and CO2 showing interesting separation factors.

References

1. A. Larbot et al. J. Memb. Sci. 1988, 39, 203-212. 2. S. Alami-Younssi et al. J. Memb. Sci. 1998, 143, 27-36.

SPM22


Improving the stress tolerance of the oleaginous yeast Lipomyces starkeyi for industrial purposes

Danilo Porro, Francesca Martani, Mattia Torchio, Letizia Maestroni, Paola Branduardi.

University of Milano Bicocca, Dept BTBS, Milan, Italy.


An emerging potential alternative for biodiesel production is represented by microbial lipids, also referred as single-cell oils (SCOs), which could lead to a green and sustainable biodiesel production process, with no competition with the food supply chain. Many microorganisms belonging to the genera of algae, bacteria, yeast and fungi can accumulate lipids under specific cultivation conditions. Among them, the utilization of oleaginous yeast is advantageous due to fast growth rate and high oil content compared to algae. A sustainable production of SCOs implies the utilization of lignocellulosic biomasses as substrate for growth. Unfortunately, during their hydrolysis different inhibitory molecules are formed, limiting cell growth and, consequently, SCOs production. The development of robust cell factories is therefore crucial for the establishment of sustainable processes. Strategies to improve the stress tolerance of the oleaginous yeast Lipomyces starkeyi will be described, together with their effect on SCOs production. Acknowledgements: This work was funded by Fondazione Cariplo (#conFondazioneCariplo), project BEETOUT.

SPM23


Synthesis of (1H)-Isochromen-1-ones by Palladium-Catalyzed Carbonylation of 2-Alkynylbenzoic Acids

R. Mancuso, M. Novello, I. Ziccarelli, B. Gabriele

Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technology, University of Calabria, Via Pietro Bucci, 12/C, 87036 Arcavacata di Rende (CS), Italy;

[email protected] In this communication we report a novel method for the synthesis of functionalized isochromenone 2 derivatives based on PdI2-catalyzed oxidative heterocyclization-carbonylation of 2-(3,3-dimethylbut-1-yn-1-yl)benzoic acids 1 (Scheme 1). Reactions were carried out a 100°C and under 20 atm of 4:1 mixture of CO-air, in the presence of catalytic amount of PdI2 (1 mol %) in conjunction with KI (10 mol %).

Scheme 1

The presence of the tert-butyl group on the triple bond favored the 6-endo cyclization mode, with exclusive formation of (1H)-isochromen-1-ones 2. Products were obtained in good isolated yields (60-95%), and the structure of some representative products was confirmed by XRD analysis.

SPM24


Effect of iron addition on the catalytic activity of manganese oxides electrodeposited films in the water oxidation reaction

M. Etzi Coeller Pascuzzi,a S. Hernandez,a,b A. Sacco,b M. Castellino,b P. Rivolo,a B. Bonelli,a,c

M. Armandia aDepartment of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin, Italy

bCenter for Sustainable Future Technologies, CSFT@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Turin, Italy

cINSTM Unit of Torino-Politecnico e-mail: [email protected]

There is currently a great interest towards the water splitting (WS) reaction as a promising means to store solar energy [1]. Out of the two half-reactions involved in WS, water oxidation (WO) is the most challenging one, and it is usually considered as the bottleneck of the whole WS process. Manganese oxides (MnOx), being active, earth-abundant and low-toxicity materials, are currently considered as promising water oxidation catalysts [2]. In this context, we firstly report on the optimization and characterization of mixed Fe/Mn oxide films as catalysts for the WO reaction at neutral pH (0.1 M buffer phosphate). Cathodic electrodeposition at constant current density allows a facile and rapid synthesis and a homogeneous coverage of the electrode. The optimal range of Fe(NO3)3 concentration in a KMnO4 deposition solution was investigated, showing the beneficial effect of Fe addition both in terms of activity and stability of the catalyst. Electrochemical Impedance Spectroscopy (EIS) measurements showed that both electrode charge-transport properties and electrode–electrolyte charge transfer kinetics are enhanced for optimal iron content.

Figure: Tafel Plot (left) and Chronopotentiometry at 0.1 mA cm-2 (right) for samples electrodeposited from 1.5 mM KMnO4 solutions containing different Fe(III) amounts.

References

1. Bensaid, S., Centi, G., Garrone, E., Perathoner, S., Saracco, G. ChemSusChem 2012, 5, 500-521. 2. Ottone, C., Armandi, M., Hernandez, S., Bensaid, S., Fontana, M., Pirri, C.F., Saracco, G., Garrone, E., Bonelli,

B. Chem. Eng. J. 2015, 278, 36-45.

SPM25


Green Strategies for the Synthesis of Sugar-Fatty Acid Esters

V. Pappalardo, F. Zaccheria, R. Psaro, N. Ravasio Consiglio Nazionale delle Ricerche - Istituto di Scienze e Tecnologie Molecolari, Milano, Italia


Sugar fatty acid esters are amphiphilic compounds widely employed as food-grade, biodegradable, non-toxic, and non-ionic surfactant in industrial formulations in place of the synthetic ones.1 They are easily digested as a mixture of sugars and fatty acids in the stomach and some of them showed antimicrobial, anticancer and insecticidal activity.2 These compounds can be produced from renewable and low-cost raw materials (viz carbohydrates, fatty acids or oils) by using both chemical and enzymatic esterification. Even if the chemical route, that is transesterification of the fatty acid methyl ester with the sugar, is the most widespread at an industrial level, in the last decade the enzymatic route has arouse interest because of the higher regioselectivity and the eco-friendly reaction conditions. We synthesized L-(+)-arabinose-palmitic acid monoesters by using immobilized Candida antarctica lipase B (Novozyme 435) as a biocatalyst, to provide environmental and human safer surfactants. The effect of the reaction medium, temperature and molar ratio of reagents, that strongly affect the activity and specificity of lipases, has been investigated. The product was purified by flash chromatography and characterized by NMR, ATR-FTIR, ESI-MS analyses. The thermal properties were evaluated by DSC.3

To the best of our knowledge, the direct esterification of L-(+)-arabinose and free palmitic acid has not been exploited, and few studies on the direct esterification of other underivatized sugars and free fatty acids have been so far performed.4 By using this approach, we synthesized other sugar-fatty acid monoesters such as arabinose oleate, glucose palmitate and glucose oleate. The enzymatic route allows to obtain sugar monoesters as main products, however many industrial applications require the use of polyesters. Another drawback of this approach is the poor solubility of sugars in non-polar solvent in which lipases show activity, or vice versa the low lipase activity in polar solvents in which sugars are soluble, leading to long reaction time and low yields. To overcome these limitations, following our previous works on solid Lewis acid materials5, we began to study the activity of clays as heterogeneous acid catalysts, in particular Montmorillonite, a layered aluminosilicate that showed a high activity in the esterification of polyols with long-chain fatty acids, being also environmentally friendly, cheap, thermally stable and easily to recover.6

References

1. Van Kempen, S. E. H. J., Boeriu, C. G., Schols, H. A., De Waard, P., Van der Linden, E., Sagis, L. M. C., Food Chem. 2013, 138, 1884-1891.

2. Xin, L., J. Chem. Pharm. Res. 2014, 6, 944-946. 3. Pappalardo, V. M., Boeriu, C. G., Zaccheria, F., Ravasio, N., Mol. Catal. 2017, 433, 383-390. 4. Van Den Broek, L.A.M., Boeriu, C.G., Carbohydr. Polym. 2013, 93, 65-72. 5. Zaccheria, F., Mariani, M., Psaro, R., Bondioli, P., Ravasio, N., Appl. Catal., B. 2016, 181, 581-586. 6. Chaari, A., Neji, S. B., Frikha, M. H., J Oleo Sci. 2017, 66, 455-461.

SPM26


Epoxidation of Millettia pinnata oil methyl esters in the presence of hydrogen peroxide over a simple niobium-grafted catalyst

N. Scottia, N. Ravasioa, C. Evangelistia, R. Psaroa, M. Pensoa, F. Zaccheriaa,

P. Niphadkarb, V. Bokadeb, M. Guidottia aCNR - Institute of Molecular Sciences and Technologies, Milano, Italy

bCSIR-National Chemical Laboratory, Pune, India e-mail: [email protected]

Epoxide derivatives of vegetable oil fatty acid methyl esters (FAMEs) proved to be among the most versatile intermediates in oleochemistry, as they can be easily transformed into a broad series of key products through oxirane ring opening [1]. In this aim, niobium-based silica catalysts are suitable and robust heterogeneous catalysts for the environmentally-friendly epoxidation reactions of unsaturated FAMEs in the presence of use of aqueous hydrogen peroxide [2]. The present study aims at considering the performance of a conceptually simple, novel Nb-SiO2 catalyst, obtained via a chemisorption-hydrolysis procedure, starting from cheap and viable reactants [3]. Such system was then tested in the liquid-phase epoxidation, in the presence of aqueous (30 wt.%) hydrogen peroxide, of methyl oleate (Me-OLE), as a model substrate, and of the mixture of methyl esters obtained by transesterification with methanol and purification by distillation of the karanja oil, extracted from an autochthonous Indian variety of Millettia pinnata tree. Karanja FAME mixture contains a remarkable fraction of unsaturated esters: 51.6, 17.7, 0.7, 0.8 wt.% for C18:1, C18:2 and C20:1 and C22:1, respectively. The Nb-SiO2 catalyst (0.95 Nb wt.%) was prepared by alkaline deposition of NH4Nb(C2O4)2ꞏH2O in the presence of fructose as a stabiliser and subsequent calcination at 350°C, 4 h in air and then characterized by physico-chemical characterization (XRD, DRS-UV-vis, HR-TEM and STEM). The sample showed a relevant fraction of isolated Nb(IV) sites, with UV absorption maxima around 225-230 nm, no major bulky aggregates of Nb2O5 species being evident. In batch epoxidation tests (Tab. 1) the Nb-SiO2 solid showed a promising performance in terms of Me-OLE conversion (up to 75%) and epoxide selectivity (up to 80%). These data are consistent with those recorded over a benchmark catalyst, such as an ordered mesoporous Nb-MCM-41 catalyst, which was slightly more active, albeit prepared via a more complex and expensive synthesis route. The catalyst was then tested on the FAME mixture from karanja oil, where interesting conversion values were attained, although with lower selectivities and yields to the desired mixture of desired epoxidized FAMEs.

Table 1. Performance of Nb-SiO2 catalyst (0.95 wt.%) in the catalytic epoxidation of FAMEs FAME H2O2:C=C ratio time (h) ConvC=C (mol%) Selepox (mol%) Yieldepox(mol%)Me-OLE 1:4 4 57 74 42 Me-OLE 1:4 24 75 80 60 Karanja mix 1:4 24 78 58 45 Conditions: 100 mg catalyst pre-treated 500°C dry air; 6 mL CH3CN; batch reactor. References

1. Guidotti M., Palumbo C., in: Atwood D.A. (Ed.), Encyclopaedia of Inorganic and Bioinorganic Chemistry. 2016, Wiley, Chichester, 373–385.

2. Dworakowska S., et al., J. Cleaner Prod., 2017, 166, 901-909. 3. F. Zaccheria, et al., Dalton Trans., 2013, 42, 1319-1328.

Acknowledgements: ISTM and NCL gratefully acknowledge the CNR, Italy – CSIR, India Bilateral Programme “Development of Catalytic Renewable Process by Converting Indian Origin Non-Edible Oil to Valuable Chemicals” for partial financial support.

SPM27


Cynara Cardunculus seed oil: a promising source for the production of biodegradable Poly(lactic acid) plasticisers

R. Turcoa, G. Santagatab, S. Mallardob, M. Malinconicob, M.E. Cucciolitoa, R.Tessera

aUniversity of Naples Federico II, Department of Chemical Sciences, Complesso Universitario di Monte Sant’Angelo, 80126 Naples, Italy

bInstitute for Polymers, Composites and Biomaterials, National Council of Research, Via Campi Flegrei 34, 80078 Pozzuoli, Italy


Cardoon seed oil (Cynara Cardunculus) has been attracting an increasing interest in Italy for the bio-plastic industry. Cardoon is a wild robust perennial plant, native from the Mediterranean basin. Its production can reach 30–35 t/(ha year), and the dried flowers of this plant have been used since ancient times in southern Europe as vegetable rennet, to prepare high-quality traditional milk from goat and sheep. Cardoon seeds contain high oil content (25–33%), and their composition is based on mono-, di- and triglycerides [1]. The composition in fatty acids of the Cardoon oil (CO) is similar to that of the sunflower oil, around: 60.9% linoleic, 23.6% oleic, 12.1% palmitic and 3.4% stearic acid. Moreover, Cardoon does not compete for land as far as edible resources are concerned, and the related crop does not need high quality of arable land nor fertilisers/herbicide pre-treatment, differently from what happens for materials coming from sunflower or soybean [2]. CO represents an interesting potential non-food plant oil: it can be cultivated on the contaminated soils of the Campania region (Italy), i.e. the land known with the name “terra dei fuochi” (land of fires), because it very well adapts with the local climate conditions, and through a phytoremediation process it is possible to have available a suitable plant-oil otherwise not usable for the human food. The aim of this work is the preparation of biodegradable and non-toxic plasticisers by epoxidation reaction of CO and the study of their potential plasticising effect in environmentally friendly polymers like poly(lactic acid) (PLA). This aliphatic polyester, coming from plants fermented starch, is regarded as a promising alternative to some petro-based polymers due to its noteworthy mechanical properties such as tensile strength and Young’s modulus. As most of the polyesters, the main drawback of PLA that prevents some commercial applications, concerns its brittleness and lower impact resistance [3]. Over the past, the use of proper plasticisers has been shown as a valid solution to enhance its flexibility and toughness. The epoxidized soybean oil (ESO) is well recognised to be an efficient plasticiser for PVC and other plastics, in addition with the beneficial aspects derived by its biodegradable and non-toxic nature [4]. However, this edible plasticiser feedstock may raise serious issues concerning the competition with food supply and deforestation due to the massive propagation of edible plants. Therefore, the use of CO appears advantageous to prepare biodegradable plasticisers for PLA. For this purpose, in this work, after a preliminary characterization, CO has been successfully epoxidized by performic acid, in fed-batch modality. Then some blends of PLA_ECO, i.e. with different amounts of epoxidized Cardoon oil (ECO), have been prepared and characterised by thermal, mechanical and spectroscopic analysis. A final comparison with analogous blends of PLA_ESO has shown that ECO is an effective green plasticiser for PLA. References

1. Alexandre A.M.R.C., Dias A.M.A, Seabra I.J., Portugal A.A.T.G., de Sousa H.C., Braga M.E.M., L. J. Supercritical Fluids. 2012, 68, 52-63.

2. Torres C.M., Rios S.D., Torras C., Salvado J., Mateo-Sanz J.M. Fuel. 2013,111, 535-542. 3. Angelini S., Cerruti P., Immirzi B., Santagata G., Scarinzi G., Malinconico M. International Journal of Biological

Macromolecules. 2014, 71, 163–173. 4. Turco R., Pischetola C., Di Serio M., Vitiello R., Tesser R., Santacesaria E., Ind. Eng. Chem. Res. 2017, 56,

7930–7936. Acknowledgements: This work was funded by Finanziamento della Ricerca di Ateneo (000023ALTRI_DR_3450_2016_Ricerca di Ateneo-CA_BIO).

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Copper homeostasis as a target to improve Saccharomyces cerevisiae tolerance to oxidative stress

N. M. Berterame, Francesca Martani, Danilo Porro, Paola Branduardi

Department of Biotechnology and Biosciences, University of Milano Bicocca, Piazza della Scienza 2, 20126, Milan, Italy

e-mail: [email protected] The yeast Saccharomyces cerevisiae is widely used as a cell factory for the biotechnological production of various industrial products. During these processes, yeasts meet different kinds of stressors that often cause oxidative stress and thus impair cell growth. Therefore, the development of robust strains is indispensable to improve production, yield and productivity of fermentative processes. Copper plays a key role in the response to oxidative stress, as cofactor of the cytosolic superoxide dismutase (Sod1) and being contained in metallochaperone and metallothioneines with antioxidant properties. In this work, we observed a higher naturally copper internalization in a robust S. cerevisiae strain engineered to produce the antioxidant L-ascorbic acid (L-AA), compared with the wild type strain. Therefore, we investigated the effect of the alteration of copper homeostasis on cellular stress tolerance. CTR1 and FRE1 genes, codifying for a plasma membrane high-affinity copper transporter and for a cell-surface ferric/cupric reductase, respectively, were overexpressed in both wild type and L-AA cells. Remarkably, we found that the sole FRE1 overexpression was sufficient to increase copper internalization leading to an enhanced stress tolerance toward H2O2 exposure, in both strains under investigation. These findings reveal copper homeostasis as a target for the development of robust cell factories. Acknowledgements: This work was partially supported by the University of Milano Bicocca with the FA (Fondo di Ateneo) to PB and the post-Doctoral fellowship to FM, and by Food Social Sensor Network (Food NET) funded by Programma Operativo Regionale 2014-2020 (Regione Lombardia) to PB and NMB.

SPM29


New sustainable solvents of vegetable origin

Martino Di Serio, Vincenzo Benessere, Maria Elena Cucciolito, Roberto Esposito, Massimo Melchiorre, Francesco Ruffo

aDipartimento di Scienze Chimiche, Università di Napoli Federico II Complesso Universitario di Monte S.Angelo, via Cintia 21, 80126 Napoli (Italia)


Fats and oils are fractions of biomass that deserve attention, due to their availability and reasonable costs, and because they possess functional groups suitable for industrial applications. Unsaturated acids derived from vegetable oils are privileged materials, since their oxidation yields diacids, useful for several industrial applications. The oxidation of oleic acid (monounsaturated C18:1 fatty acid) provides the C9 mono- and dicarboxylic acids (pelargonic and azelaic acid), which are rare in natural systems:

While azelaic acid is already extensively applied in the manufacture of plastic materials, cosmetics and pharmaceuticals, the stoichiometric counterpart, pelargonic acid, has not yet found a definite use, and, hence, the presence of this by-product greatly lowers the atomic efficiency of the oxidation process. This circumstance, combined with the convenience of the synthetic method developed by our laboratory,1 has inspired us to verify the suitability of its esters as solvents for varnishes. In this report, we describe the successful scale-up of the oxidation process, that has allowed us to prepare pelargonic acid esters in sufficient amounts to formulate varnishes in combination with a commercial resin (Rosin ester). References 1. Benessere V., Cucciolito M.E., De Santis A., Di Serio M., Esposito R., Ruffo F., Turco R. J. Am. Oil. Chem. Soc.

2015, 92, 1701-1707.

SPM30


Packed foams: a novel reactor configuration for enhancing heat transfer properties in methane steam reforming process

R. Balzarottia, A. Berettaa, G. Groppia, E. Tronconia

a Laboratory of Catalysis and Catalytic Processes, Dipartimento di Energia, Politecnico di Milano, Via La Masa 34, Milano, Italy


Enhancing the performances of catalytic reactors is a pivotal aspect for process intensification [1]. Even though the adoption of structured supports (honeycombs/foams) activated via washcoat deposition has been widely studied as a promising solution for packed beds reactors [2], drawbacks such as smaller catalyst inventory and issues like washcoat adhesion discourage the application of this technology at the industrial scale [3]. In this work, a novel structured reactor configuration is proposed and tested for the steam reforming of CH4. It consists of packing the voids of highly conductive open-cell foams with small catalytic pellets. This reactor layout aims at enhancing the radial heat transfer of the tubular reactor by exploiting the thermal conductivity of the solid interconnected matrix, without a significant loss of catalyst inventory. For the catalytic tests we used a Rh-based catalyst in form of alumina egg-shell particles (particles diameter of 1.8 mm) packed in FeCrAlY open cell foams (Porvair) of 12 PPI with 5 mm cell size and 0.92 void fraction (foam diameter and height of 29 mm and 25 mm, respectively). The foam void volumes were filled with catalytic particles, as shown in Fig. 1-a. Temperature profiles were recorded longitudinally across the catalytic bed by sliding thermocouples at three radial positions.

Figure 1a. Close-up view of the packed foam in the reactor; Figure 1b. Radial temperature profiles at catalytic bed outlet for packed foam (dashed line, open symbol) and packed bed (full line, full symbol) at GHSV = 5000-1 (square) and 10000 h-1 (triangle) The packed foam configuration was compared to a conventional packed bed system at the same GHSV. In order to have the same reactor volume as for the packed foam layout, SiC particles were added to the bed (SiC/catalyst weight ratio of 1.54). Catalytic tests were performed in the 600-800 °C range feeding a steam/CH4 mixture with S/C ratio of 3.5 at GHSV of 5000 and 10000 h-1. Results show an improvement of CH4 conversion in the packed foam over the packed bed, at fixed furnace temperature (i.e. from 92% to 95% at GHSV = 10000 h-1 and furnace temperature of 800 °C). This behavior can be ascribed to the reduced heat transfer resistances from reactor wall to the catalyst, which enabled smaller temperature gradients and flatter T-profiles along the radial direction (Fig. 1-b) thanks to the conductivity of the interconnected open cellular matrix. References

1. Gascon, J. et al., Catal. Sci. Technol. 2015, 5, 807-817. 2. Tronconi, E. et al., Curr. Opin. Chem. Eng. 2014, 5, 55-67. 3. Visconti, C.G. et al., Cat. Today 2016, 273, 178-186.

Acknowledgements: This project has received funding from the European Research Council under Grant Agreement no. 694910 (INTENT).

SPM31


Preparation and evaluation of Ti/TiO2 photoanodes fabricated via dip-coating technique for photo-electrochemical water splitting

Lucio Scandolaa, Saverio Latorrataa, Roberto Matarreseb, Cinzia Cristiania, Isabella Novab

aChemistry and materials science department, Politecnico di Milano, Milan, Italy. b Laboratory of Catalysis and Catalytic Processes, Energy department, Politecnico di Milano, Milan, Italy.


TiO2 has been the reference material for photo-electrochemical water-splitting application since the 70s [1]. The reasons behind its use lie in the high stability of this substance in aqueous environments together with its proper band structure. The latter however is also the cause of its low conversion efficiencies, which led many researches towards the chemical and morphological modification of the TiO2 photoactive layer, often through complex and expensive deposition techniques, in order to increase the number of absorbed photons and their mobility [2]. Basing on that, the aim of this work was the preparation, characterization and evaluation of the photoelectrochemical water splitting activity of TiO2 films obtained via dip-coating technique. In particular, the existing correlations between the oxide layer properties, such as thickness and adhesion, and photoelectrochemical behavior were analyzed, with the aim of identifying the optimal structures for water splitting applications. The photoanodes were prepared using a slurry whose recipe was developed in a previous work [3], starting from a powder form of TiO2 (Degussa P25), which was dispersed in water, using PVA and glycerol as stabilizers and, subsequently, dip-coated on top of acid-treated Ti slabs. Of note, one of the main critical issues to be dealt with, when producing these objects by dip-coating using an aqueous dispersion, is the surface cracking [4], due to the liquid phase removal during the thermal treatment. On this regard, the SEM analysis of the specimens pointed out a correlation between the thickness of the oxide layer and the percentage of area occupied by the crevices, which appeared during the consolidation step. In addition, the coating adhesion appeared to be strongly related to the extent of the cracking phenomena, since less cracked samples showed much lower weight losses during the adhesion tests. The slurry composition was modified, by managing the PVA and glycerol content, to achieve a lower viscosity at a 10 s-1 shear rate, considered as representative of the dip-coating application [5], for the sake of reducing the final coating thickness and increasing its quality. Ultimately, the lower adhesion of thicker coatings was found to affect the photo-catalytic performances of the photoanodes, showing lower photocurrents and efficiencies when compared with thinner ones. Finally, the acid treatment, performed on the Ti slabs, before the coating deposition, was also found to enhance the photo-catalytic properties of the final specimen. 1. Fujishima, A. and K. Honda, Electrochemical Photolysis of Water at a Semiconductor Electrode. Nature,

1972. 238(5358): p. 37-38. 2. Hans-Joachim Lewerenz, L.P., Photoelectrochemical Water Splitting, Materials, Processes and Architectures.

2013: RCSPublishing. 3. Balzarotti, R., New Formulations and Processes for Ceramic Layers Deposition on Complex Geometry

Substrates. 2016, Politecnico di Milano. 4. Santanach Carreras, E., et al., Avoiding "mud" cracks during drying of thin films from aqueous colloidal

suspensions. J Colloid Interface Sci, 2007. 313(1): p. 160-8. 5. C. Cristiani, M.V., M. Merazzi, S. Neglia, P. Forzatti, Effect of ageing time on chemical and rheological

evolution in g-Al2O3 slurries for dip-coating. Catalysis Today, 2005.

SPM32


Kinetic investigation of the Oxygen Reduction Reaction on LSCF-GDC composite electrocatalysts

Alessandro Donazzia, Giulio Cordarob, Andrea Bariccia, Matteo Zagoa, Matteo Maestria aDipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, Milan, Italy

bDipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan e-mail: [email protected]

LSCF-GDC composites are state-of-the-art cathodes for Solid Oxide Fuel Cells active at intermediate temperature (600-700°C). LSCF (La0.4Sr0.6Co0.2Fe0.8O3-δ) is a perovskite oxide with mixed ionic and electronic conductive (MIEC) properties, which confer this material the capability of supplying electrons to the adsorbed oxygen atoms and transfer the oxide ions within the lattice. This multifunctional character allows to break the paradigm of an oxygen reduction reaction (ORR) mechanism based on the Three Phase Boundary (TPB) concept, and opens an additional transport route wherein oxygen is activated and transferred in the LSCF phase, asking only for two active interfaces (2PB) [1,2]. A quantitative understanding of this alternative oxygen reduction mechanism is a requisite to optimize the cathode structure with respect to LSCF/GDC ratio, layer thickness and particle size. In the present work, a physically-based electrode model with a detailed kinetic scheme is applied to rationalize electrochemical impedance spectroscopy (EIS) experiments performed on LSCF-GDC cathodes, covering a wide range of operating conditions in terms of temperature (550-700°C) and O2 molar fraction (5-21%). The model is dynamic and heterogenous, and solves rigorous conservation equations of mass and charge in the electrode volume, taking into account gas-phase and solid-phase diffusion processes. The detailed scheme includes steps of O2 adsorption and desorption, first and second electronation of O adsorbed atoms, formation and transport of the oxygen vacancies within the bulk of the LSCF and GDC phases. When available, kinetic parameters and transport properties (vacancy diffusion, ion conductivity) are taken from the literature, whereas thermodynamic consistency criteria are applied to derive the unknown parameters. The model is validated by comparison with the experimental impedance spectra and Bode plots: a close match between simulated and measured curves is obtained (Fig. 1A). A sensitivity analysis allows to highlight the most important morphologic and kinetic parameters and to individuate the Rate Determining Step of the ORR (Fig. 1B). The reaction path analysis shows that a competition between the 2PB and the TPB routes emerges at high temperature (700°C), while the first electronation of oxygen governs the mechanism at lower temperatures. The consequences of these results are analyzed and design criteria are proposed to minimize the polarization resistance of the composite cathode.

Figure 1. Panel A) Comparison between simulated and measured impedance spectra. 650°C, OCV, P O2 = 5 → 21%.

Panel B) Sensitivity analysis for the impedance experiment at 650°C with air supply. References

1. S. Haile, Annu. Rev. Chem. Biomol. Eng., 3 (2012) 313 2. S.B. Adler, Chem. Rev., 104 (2004) 4791–4843

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Fig 1. Calculated effect of Rh surface on hot spot T

Autothermal reforming of fossil and renewable fuels

R. Batistaa, L. Castoldia, A. Ferrettib, S. Brandãoc, G. Groppia, A. Berettaa aLaboratorio di Catalisi e Processi Catalitici, Dipartimento di Energia, Politecnico di Milano, Milano, Italy.

bCNR - ISTM c/o Dipartimento di Chimica, Università degli Studi di Milano, Milano Italy bUniversidade Federal da Bahia, Programa de Pós-Graduação em Engenharia Química, Salvador, Brasil.

e-mail: [email protected] The Catalytic Partial Oxidation (CPO) of hydrocarbons and oxygenated fuels over noble metal catalysts is a promising solution for the small-scale production of H2-rich streams. The reaction is exothermic and extremely fast; it is typically carried out in auto-thermal conditions, in compact structured reactors, at millisecond contact time. It is thus a highly intensified process, typically characterized by important temperature and concentration gradients which develop across the small catalytic bed. For all fuels, the temperature distribution is characterized by the sequence between a front oxy-reforming zone, where O2 is consumed via highly exothermic oxidation reactions and a hot spot develops and a subsequent reforming zone where endothermic steam reforming reactions lead to the formation of H2 and CO and partly reduce the temperature. In the case of logistic fuels and bio-fuels, such a iso-octane or ethanol (of interest for on-board H2 applications), high adiabatic temperatures are predicted at the reactor outlet (>1000°C) and critical issues arise or become more severe than for light hydrocarbons, such as the intensity of the hot-spot temperature, the catalyst stability, the onset of gas-phase reactions, the formation of C-deposits. In this work, we investigate the role of the support on the reactor performances with emphasis on heat management and coke formation. Rh-catalysts were prepared, characterized and coated onto ceramic monoliths.

A modelling analysis of the autothermal reformer, accounting for all the chemical and transport phenomena, indicates that a possible strategy for the minimization of the hot-spot temperature is the enhancement of the dispersion of the active element in the catalyst washcoat. Figure 1 shows as an example the effect of the increase of Rh specific surface on the calculated maximum catalyst temperature in CH4 CPO. The effect relies on the promotion of the steam reforming reactions, responsible for heat consumption.

An experimental validation was searched: a 2% wt. Rh/MgAl2O4 catalyst was prepared, characterized and tested in a lab-scale adiabatic reformer. Results

were compared with those obtained over 2% wt. Rh/α-Al2O3. Spatially resolved sampling techniques were applied for a detailed characterization of the reactor T and concentration profiles. As shown in Figure 2, much less pronounced temperatures were measured along the catalyst monolith. H2-chemisorption and HRTEM measurements confirmed that higher Rh dispersions were obtained over the MgAl2O4 support than in the over -Al2O3. TPO experiments of the tested catalysts also showed a lower tendency to C-formation. A beneficial effect on the thermal behavior and the coking resistance was observed also in the case of the

CPO of liquid HC fuels and ethanol.

Fig 2. Measured T profiles in CH4 CPO tests

SPM34

XX Congresso Nazionale di Catalisi XX Congresso Nazionale della Divisione di Chimica Industriale Supported amines for CO2 capture: DiEthanolAmine, Taurine and

PolyEthyleneImine on Alumina

P.Castellazzi a, M.Notaro a, G.Busca b, E.Finocchio b a R.S.E. S.p.A., Milano, Italy

b Dept. of Civil, Chemical and Environmental Engineering, University of Genova, Genova, Italy.


We recently proposed a study of CO2 capture on sorbent based on the Alumina-

DiEthanolAmine system (SA-DEA), investigating the effect of different amine loadings (15%, 25%, 36% wt) on adsorption processes and mechanisms. These materials have shown good adsorption properties and a noticeable regeneration capacity. Spectroscopic techniques pointed out the formation of, mainly, carbamate species during CO2 capture, which were almost completely decomposed at mild temperature1.

In this work, we compare results obtained with SA-DEA sorbents with the behaviour of two alternative organic sorbents immobilized on alumina: PolyEthyleneImine (36% wt SA-PEI), a branched amine containing primary, secondary and tertiary amino groups, and 2-Aminoethanesulfonic acid, Taurine (15% wt SA-TAU). Both these compounds possess low volatility and high decomposition temperature, thus minimizing losses during the heating in the regeneration step. The preparation procedure requires the dissolution of the organic molecules in methanol/water mixture and following addition to the dried alumina support 1. A basification step has been applied in the case of SA-TAU functionalization. The resulting materials show a specific surface area ranging from 180 to 50 m2/g, an average pore diameter 8-10 nm and a total pore volume of 0.4-0.1 cm3/g, depending on organic loading and chemical structure. IR spectroscopy evidences a main interaction of the organic molecules with surface OH groups. Several cycles of adsorption tests have been carried out in dry or wet conditions over the modified alumina samples in form of pellets, feeding a mixture 10% v/v CO2, 3% O2, N2 at balance (10% H2O in wet conditions). The best adsorption and reusability results have been obtained on DEA-based materials, for which spectroscopic studies evidenced the formation of surface carbamate species. The modified PEI and TAU materials show interesting adsorption capacity too, however a limited regeneration of the used sorbents was detected. CO2 adsorption performed directly in the IR cell points out that the adsorption is also limited with respect to the SA-DEA samples. The analysis of the SA-TAU surface evidences that amino groups are free to interact with CO2 and several intermediate adsorption species are formed, including: carbamate and amide-like groups (from reaction of CO2 with –NH2 of TAU) and bidentate and monodentate carbonate species (formed after reaction with residual adsorbed water and hydroxy groups at the alumina surface). Similar findings are reported for SA-PEI: amino groups are available for CO2 adsorption, which results in the detection of adsorbed species resisting to decomposition up to 200°C. At this temperature, however, also some chemical modifications of the PEI structure occur.

In sum: the complexity of the spectra recorded after CO2 adsorption suggests the formation of several adsorbed species having different chemical nature and thermal resistance. This effect could explain the different behavior in the regeneration step we found in our conditions for these solid sorbents. References 1. Castellazzi, P., Notaro, M., Busca, G., Finocchio, E. Microporous Mesoporous Mater. 2016, 226, 444-453.

SPM35


Gas Explosions Under Process Conditions

V. Di Sarlia, F. Cammarotaa, E. Salzanob, A. Di Benedettoc aIstituto di Ricerche sulla Combustione, Consiglio Nazionale delle Ricerche, Napoli, Italy.

bDipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Alma Mater Studiorum - Università di Bologna, Bologna, Italy.

cDipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Napoli, Italy.


Gas explosions are one of the main hazards in chemical and process industries. In order to prevent and mitigate their risks, the explosion behavior of flammable gases has to be fully characterized and quantified in terms of the so-called “explosion parameters” [1]. Most of the literature studies in the field of gas explosions have been focused on phenomena that occur starting from ambient conditions (typically, fuel/air mixture ignited at ambient temperature and pressure, and starting from quiescence). However, in the practice, explosions may occur under much more severe process conditions, and this issue may strongly affect their course [2-5]. This work is a review of the results we obtained from gas explosion experiments performed under realistic process conditions. The dependence of the explosion behavior and parameters (maximum explosion pressure, maximum rate of pressure rise, and deflagration index) on initial temperature, pressure and turbulence level will be discussed. Furthermore, a novel explosion mode, which we have called “Combustion-induced Rapid Phase Transition” (CRPT), arising under oxy-combustion conditions (i.e., when the fuel is burned in oxygen-enriched air) [6] will be described. References

1. Crowl, D. A. Understanding Explosions (Center for Chemical Process Safety of the American Institute of Chemical Engineers, New York) 2003.

2. Gieras, M., Klemens, R., Rarata, G., Wolański, P. J. Loss Prev. Process Ind. 2006, 19, 263-270. 3. Cammarota, F., Di Benedetto, A., Di Sarli, V., Salzano, E., Russo, G. J. Loss Prev. Process Ind. 2009, 22, 607-

613. 4. Giurcan, V., Mitu, M., Razus, D., Oancea, D., Process Saf. Environ. Prot. 2017, 111, 94-101. 5. Mitu, M., Brandes, E. Fuel 2017, 203, 460-468. 6. Di Benedetto, A., Cammarota, F., Di Sarli, V., Salzano, E., Russo, G. Combust. Flame 2011, 158, 2214-2219.

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SPM38


Study of the ageing of Lean DeNOx Trap Catalyst

T.Pellegrinellia, A.Gogueta, G.McCollougha , I.Murrayb, R.Caporalib aQueen’s University Belfast, Belfast, BT71NN, UK.

bFord Motor Company, Brentwood Essex, CM133BW, UK. e-mail: [email protected]

Introduction

Lean DeNOx trap technology is one the most common NOx emission control system for diesel vehicles. Modern LNT formulations are typically composed on PtPdRh/Ba/Ce–Zr/Al2O3 and high temperature stabilizers. Although this system has been widely studied, thermal degradation remains one of the major issues with this catalyst[1]. Thermal ageing is induced by periodical de-sulphuration cycles performed by the engine at temperatures of about 650°C to recover from sulphur poisoning. However, the extreme conditions required lead to an irreversible deterioration of the PGMs[2]. In this study, hydrothermally aged LNT samples are adopted to investigate how the degradation of the PGMs effect the performances of the system. These results will be used to develop a model of the ageing process which is able to predict the loss of performance of the system over the time.

Materials and Methods

The study was conducted on two LNT monolith provided by Ford Motor Company. The washcoat formulation was of the type PtPdRh/Ba/Ce–Zr/Al2O3. One sample was treated with a mild-hydrothermal ageing process and it is referred as fresh sample. The second sample, referred as aged sample, was treated with a severe hydrothermal ageing process. The catalytic activities were evaluated on a synthetic bench-scale reactor using NOx storage capacity experiments at temperatures between 200°C and 400°C in presence of a lean mixture. Purge tests to evaluate the reduction abilities of the catalyst were also carried out between 200°C and 400°C. Light off experiments were performed feeding a lean gas mixture during a temperature ramp from 100°C to 500◌ۣ°C at a rate of 10°C/min.

Results and Discussion

As can be seen from fig.1, the aged sample shows a net loss in terms of storage capacity which may be attributed to a decrease of interface between platinum and barium[3][4]. The loss of Pt-Ba intimacy is under current study and may be caused by phenomena of sintering or migration of PGMs particles. A decrease PGMs activity was aksi in the light-off curves with an increase of light-off temperature of about 20°C for both CO and C3H6 following the hydrothermal ageing treatment. Moreover, during the purge tests the aged sample exhibits a net loss of performances. The decrease in N2 selectivity and increase of ammonia, CO and NOx slip reported in fig.2 denotes an overall decrease of reduction and oxygen storage properties.

[1] W.S. Epling, L.E. Campbell, A. Yezerets, N.W. Currier, J.E. Parks, Catal. Rev. 46 (2004) 163–245. [2] M. Maurer, T. Fortner, P. Holler, S. Zarl, H. Eichlseder, Automot. Engine Technol. 2 (2017) 63–77. [3] B.M. Weiss, K.B. Caldwell, E. Iglesia, J. Phys. Chem. C 115 (2011) 6561–6570. [4] D.H. Kim, Y. Chin, G.G. Muntean, A. Yezeretz, N.W. Currier, W.S. Epling, H. Chen, H. Hess, C.H.F. Peden, (2006) 8815–

8821. [5] L. Lietti, I. Nova, P. Forzatti, J. Catal. 257 (2008) 270–282. [6] Y. Ji, V. Easterling, U. Graham, C. Fisk, M. Crocker, J.S. Choi, Appl. Catal. B Environ. 103 (2011) 413–427. Acknowledgements: This research is sponsored by Ford Motor Company.

Figure 1: NOx storage capacity of thefresh sample and the aged sample overthe temperature.

Figure 2: Results of purge tests in terms of selectivity towards N2, N2O,NH3 and N2 and CO conversion of the fresh sample (a) and the agedsample(b) over the temperature.

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