1

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)

2

3

Il carbonio sp3

4

S 2px

2py2pz

4 orbitali sp3

5

C H

6

METANO

CH4

H C

H

H

H

H

CH

HH

H

CH

HH

H

CH

HH

7

1 Angstrom = 1.0 × 10-10

metri

1.10 Å

109.5°

8

9

Melvin Spencer Newman (March 10, 1908 - May 30, 1993) an American chemist of Ohio State University who introduced the Newman projections in 1952

10

11

12

1 2

3

13

Stessa FormulaMINIMA?

Non sonoISOMERI

Differiscono per rotazione libera

attorno a legami?CONFORMERI

NO

SISTEREO-ISOMERI

StessaCONCATENAZIONE

di atomi?

????

SI

NO

SI

21

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...

14

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

15

16

sec- e terz- non influiscono l’ordine alfabetico.Pertanto il terz-butile precede l’etile e l’etile precede l’isobutile.

17

18

19

H

H H

CH3

CH2CH3H

isoottano

Research Octane Number (RON):

diesel 15-25benzina 95 (obbl. IT)

benzina arricch. 100-101.5

20

H3C

CH2

CH2

CH2

CH2

CH2

CH3

CH3(CH2)5CH3

21

Scrivere gli alcani di formula

C3H8 C4H10C5H……

C6H…………….

22

Proprietà chimico-fisiche

degli alcani

23

24

25

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

26

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

27

•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.

40.00 42.00 44.00 46.00 48.00 50.00 52.00 54.00 56.00 58.00

0

Polistes dominulus: cuticular hydrocarbons

Abu

ndan

ce

1

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

31

10

}

}

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

28

(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)

29

Ma soprattutto danni cerebrali

9

Aprile

2013

30

9

Aprile

2013