北京大学：《有机化学》第二章 烷烃

Chapter2烷烃( Alkanes) 烃类化合物( Hydrocarbons 脂肪族( Aliphatic 芳香族( Aromatic) 烷烃烯烃炔烃脂坏烃 Alkanes Alkenes Alkynes Cyclic Aliphatic

Chapter.2 烷烃 (Alkanes) 烃类化合物(Hydrocarbons) 脂肪族(Aliphatic) 芳香族(Aromatic) 烷烃 Alkanes 烯烃 Alkenes 炔烃 Alkynes 脂环烃 Cyclic Aliphatic

二烷烃的结构和命名:( Structure and nomenclature) 1.结构: SP杂化,四面体结构,键角109°28 C-C O Bond Is Is Is 2p 2p a bond a bond o bond A B C

1. 结构： SP3杂化， 四面体结构， 键角 109º28´ C-C :σ Bond 一.烷烃的结构和命名：(Structure and Nomenclature)

2通式:( General Formula) Alkane: CnH2n+2 CH3叔仲伯 CH3-C-CH-CH2-CH3 Alkyl: Cn2n+1季CH3CH 3命名:(N (1). Common Names of Alkanes 1~10碳:甲,乙,丙,丁,戊,已,庚,辛,壬,癸 Methane, Ethane -a-Decane 同分异构:( sommers)

2.通式： （General Formula) Alkane: Cn H2n+2 Alkyl: Cn H2n+1 CH3 C CH CH2 CH3 CH3 CH3CH3 叔 仲 伯 季 3.命名：( N (1). Common Names of Alkanes: 1~10碳： 甲， 乙，丙，丁，戊，己，庚，辛，壬，癸 Methane, Ethane,---------------------Decane 同分异构：(Isomers)

同分异构:( somers CH3CH2CH2CH2 IE( n-butyl CH3--CH-CH2- (iso-butyl CH3 3 CH3-CH 叔(t-buty) CH3 3 CH3CHC2新(neo- penty CH3

CH3 CH2 CH2 CH2 正 ( n-butyl.) CH CH3 CH3 CH2 异 ( iso- butyl) 同分异构：(Isomers) CH CH3 CH3 叔 (t- butyl) CH3 CH CH3 CH3 CH2 CH3 新 （neo-pentyl)

(2).IUPAC Names of Alkanes 直链: Unbranched a| kanes 支链: Branched alkanes a.常见的烷基: Alkyl group CH3-CHCH2iso-buty异 CH CHCH2CHCH3 sec-butyl仲 3 CH3 tert- butyl叔 CH3 CH3 CH Neo-pentyl 2 新 CH 3

(2). IUPAC Names of Alkanes 直链： Unbranched Alkanes 支链: Branched Alkanes a. 常见的烷基：Alkyl group CH CH3 CH3 CH3 CH2 CH2 CH3 { CH iso-butyl sec-butyl 异 仲 CH3 CH3 CH2 { C CH3 CH3 CH3 C CH3 tert -butyl Neo-pentyl 叔 新

b.主链的选择:选择含取代基多的碳链 CH3-CH2-CH-CH2-CH3 CH-CH3 CH3 C主链的编号:取代基编号的位次最小 23 CH3-CH-CH2-CH-CH-CH2-CH3 CH3 6 >2--C13 CH3-CH-CH 8 2,6二甲基5乙基辛烷 d书写取代基的规则:优先基团列在后面

b. 主链的选择： CH3 CH2 CH3 CH CH2 CH CH3 CH3 选择含取代基多的碳链 c.主链的编号： CH3 CH CH CH3 CH2 CH2 CH CH2 CH3 CH3 CH2 CH3 1 2 3 4 5 6 7 8 取代基编号的位次最小 2，6-二甲基-5-乙基辛烷 d.书写取代基的规则： 优先基团列在后面

e.复杂支链烷烃的命名 12 3 5678 CH3-CH,-CH-CH-CHCH-CH2-CH2 CH2-CH3 CH3 CH3-C-CH2-CH3 CH3 3甲基6(1,1二甲基丙基)癸烷 二构象( Conformation): Sawhorse Model锯木架式: Newman Projection投影式 透视式 Perspective

e. 复杂支链烷烃的命名 CH2 CH C CH3 CH3 CH CH3 CH2 CH2 CH3 CH3 CH2 CH3 1 2 3 4 5 6 7 8 9 CH2 CH2 CH2 10 3-甲基-6（1，1-二甲基丙基）癸烷 二 构象 ( Conformation): Sawhorse Model 锯木架式: Newman Projection 投影式: 透视式 Perspective

H H H H H H H H O 、→ OH HH

(二)构象变化及能量图: CHa HCH3 CH H3CCH3 CHa H HaC CHa ctc H H H H hhH H CHa Anti Gauche Gauche

(二） 构象变化及能量图：

HaC CH3 H CH H CHa H H3 E Ea2=3.6 kcal Eal-3. 8 keal Ea3-2.9 kcal 1 o 0.9 kcal mol-l CH3 CH3 CH H HC H CHs H H CH3 CHa 0 120 240