有机化学课件chapter第三章重点讲解内容

三三1（Unsaturated1PAGEPAGE2 Question1:WhatisunsaturatedAnswer:Hydrocarbonsthosecontainsp2orsphybridcarbonsarecalledunsaturatedQuestion2:Howmanykindofunsaturatedhydrocarbonsaret Answer:Theyc lassifiedintoalkenes,alkynesandaromatichydrocarbons. 1

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66PAGEPAGE7构型——使用“Z”(德文zusammen,同)，“E”BBCCADCB>D为"Z"若A>C为"E"8(E)-3,6-二甲基-5- 1345679CHCHCH2C-2,5,9-十二碳三烯 CH3CHCHC CH3CCH2CH2CHCCH

HCCCHCH 烯烃和炔烃:加成反应（π键断裂发生加成反应 CHCH

乙醇

烯烃和炔烃:加成反 R'

RCO

R R''

R'

H

OO or

RO+

RO+

O

不饱和碳氢化合物的稳定燃烧热（∆HcӨ—— + O2(g)2

nCO2(g)+nH

生成热（∆HfӨ——nC+ h氢化热（∆HӨ)1mol烯烃，在标准条件h——双键+ ————氢化热越高， ~<<~<<<<

烯烃的稳定性CH3CHCH anisolated

acumulated CH aconjugatedC+++-70.5-60.8-54.1CCCCC=CCCCC HHCCHHCHCH面；p轨道垂直于该平面，体系即形成大电子离域，产生离域能(共轭能)。共轭键与键的。(电子离域,体系稳定AnunusuallylargeresonanceenergyBenzeneparticularlystablebecauseoftheresonanceenergyButcyclobutadieneandcyclooctatetraenecontainscyclictwoorfourpi-bond,theyarenotstable.1938年,德国化学家ErichHückel根据对苯以及多种轮烯的研究，总结出了休克尔规则（Hückel’sItisalsocalled4n+244+4+4+4+ _

平面正八边形环辛四烯双负离子 +

芳香性芳香性 Exnation1——价键理SinglebondbetweenC-Cformedbysp2-vrl ln fh hr thereforethebondisstronger.

154150146139 +-70.5

+

+-60.8-54.1 Buthowcanwe (3)为什么环

Expanation2antibondingpi-molecular 2patomic

2patomicbondingpi-molecular最高被占轨道（HOMO，thehighestoccupied最低空轨道（LUMO，thelowestunoccupied 0

antibonding 2

p

1,3-

1,3,5- 0

antibondingnonbonding 2

bondingp

1,3-

1,3,5- 0 2

1,3-1,3,5-己三 + = （0.445×21.247×21.802×26.988） 2环 in6 (远远大于6，也大于1,3,5-己三烯的成键in道的电，相当于双自由基，应具有反香性，8inotheraromaticmoleculesor p-electronsinconjugateddienesandbenzeneare离域的电子结构可以用经的 AcompoundwithdelocalizedelectronsissaidtoTheapproximatestructureusinglocalizedelectronsiscalledaresonancecontributor,aresonancestructure,oracontributingresonancestructureTheactualstructure,drawnusingdelocalizeletrons,iscalledaresonancehybrid（杂化thefollowingwaysMoveπelectronstowardaπthefollowingwaysMoveπelectronstowardapositive

thefollowingwaysMoveanonbondingpairofelectronstowardaπthefollowingways Move