III IV V VI VII · III IV V VI VII III IV V VI VII EN (aumenta il n. protoni => maggiore attrazione...
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1 III IV V VI VII III IV V VI VII EN (aumenta il n. protoni => maggiore attrazione degli e-) EN (e- più vicini al nucleo)
Transcript of III IV V VI VII · III IV V VI VII III IV V VI VII EN (aumenta il n. protoni => maggiore attrazione...
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III IV V VI VII
III IV V VI VII
EN (aumenta il n. protoni => maggiore attrazione degli e-)
EN
(e-
più
vici
ni a
l nuc
leo)
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Il carbonio sp3
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S 2px
2py2pz
4 orbitali sp3
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C H
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METANO
CH4
H C
H
H
H
H
CH
HH
H
CH
HH
H
CH
HH
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1 Angstrom = 1.0 × 10-10
metri
1.10 Å
109.5°
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Melvin Spencer Newman (March 10, 1908 - May 30, 1993) an American chemist of Ohio State University who introduced the Newman projections in 1952
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1 2
3
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Stessa FormulaMINIMA?
Non sonoISOMERI
Differiscono per rotazione libera
attorno a legami?CONFORMERI
NO
SISTEREO-ISOMERI
StessaCONCATENAZIONE
di atomi?
????
SI
NO
SI
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C C C C H
H
H
H
H
H
H
H
H
H
H C C C H
H
H
H H
H
CH
H
H
C4H...
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Stessa FormulaMINIMA?
Non sonoISOMERI
StessaCONCATENAZIONE
di atomi?
Differiscono per rotazione libera
attorno a legami?
ISOMERICOSTITUZIONALI
(di struttura)
CONFORMERI
??????????
NO
SI
NO
SI SI
NO
STEREO-ISOMERI
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sec- e terz- non influiscono l’ordine alfabetico.Pertanto il terz-butile precede l’etile e l’etile precede l’isobutile.
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H
H H
CH3
CH2CH3H
isoottano
Research Octane Number (RON):
diesel 15-25benzina 95 (obbl. IT)
benzina arricch. 100-101.5
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H3C
CH2
CH2
CH2
CH2
CH2
CH3
CH3(CH2)5CH3
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Scrivere gli alcani di formula
C3H8 C4H10C5H……
C6H…………….
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Proprietà chimico-fisiche
degli alcani
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24
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Aumento del p.toebollizione
Strutture più compatte => sviluppo superficiale minore degli alcani lineari
=> Forze di London minori => p.to eboll. e p.to fusione minori
Video WILEY CD CHEMISTRY
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20°C
150°C
200°C
300°C
370°C
400°C
> C70
C20÷C70
C20÷C50
C14÷C20
C10÷C16
C5÷C10
C5÷C9
C1÷C4
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•The insect cuticle is covered by alayer of lipids. This layer protect theinsect from infection and to reducewater loss.
•In social insects (wasps, bees, ants,and termites) cuticular compoundsalso allow individuals to recognizeeach other. Thus, individuals are ableto discriminate colony members onthe basis of the cuticular signature.
•In social insects the majorcompounds found on the cuticle arehydrocarbons. These are usuallylong-chained (C20 to C37) and maybe saturated or unsaturated.
•In social wasps (Polistes sp.)cuticular hydrocarbons have beenfound to differ between colonieswithin species and allow colonymembers to recognize nestmates.Furthermore, the nest has beenshown to be an important source ofthese hydrocarbons as well as glandspresent in the wasps.
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0
Polistes dominulus: cuticular hydrocarbons
Abu
ndan
ce
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18-23
13
11
8
7
6
432
17
2415
16
29
26
28
33 34
35-38
5
9 12
14
2527 30
32
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}
}
1. C252. 13-/ 11-/ 9-, meC253. C264. 2-meC265. C27:16. C277. 13-/ 11- meC278. 7-meC279. 5-meC2710. 9, y dimetil-C2711. 3-meC2712. 5, 15 dimetil-C2713. C2814. 14-/ 13-/ 12- meC2815. 2-meC2816. C2917. 15-/,13- meC2918. 7-meC2919. 5-meC2920. 11, y dimetil-C2921. 7, y dimetil-C2922. 3-meC2923. 5, y dimetil-C2924. C3025. x, y dimetil-C2926. Unknown27. C3128. 15-/, 13-, meC3129. 7-meC3130. 13, 17 dimetil-C3131. 7, 15 dimetil-C3132. 5, 15 dimetil-C3133. x, y dimetil-C3334. Unknown35. 17-/, 15-/, 13-, meC3336. 13, y dimetil-C3337. 7, y dimetil-C3338. 5, y dimetil-C33
•Chromatogram after SMPE of a live individual of Polistes dominulus
•The cuticular signature consists mainly of saturated hydrocarbons ranging from chain length C25 toC33.
•Many of these are mono- or di-methylated, unsaturated hydrocarbons are present in very smalltiti
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(CH2)23
Pentacosane (C25)
(CH2)24
Hexacosane (C26)
(CH2)25
Heptacosane (C27)
(CH2)26
Octacosane (C28)
(CH2)27
Nonacosane (C29)
(CH2)28
Triacontane (C30)
(CH2)29
Hentriacontane (C31)
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Ma soprattutto danni cerebrali
9
Aprile
2013
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9
Aprile
2013
