Chapter 8 Alkenes and alkynes l Properties and synthesis 8.1 Introduction Alkenes are hydrocarbons whose molecules contain the carbon -carbon double sonde ethylene Hydrocarbons whose molecules contain the cardencicarbonsteiple abond arengalled alkynes
Chapter 8 Alkenes and alkynes I. Properties and synthesis 8.1 Introduction Alkenes are hydrocarbons whose molecules contain the carbon-carbon double bond. Hydrocarbons whose molecules contain the carbon-carbon triple bond are called alkynes. C C H H H H Ethene or ethylene HC CH or acetylene or ethyne
8.2 Nomenclature of alkenes and cycloalkenes H2C-C CH3 IUPAC Propene common; Propylene H2c=C—cH IUPAC: 2-MethylPropene Common; Isobutylene CH C vcIohexane Cyclohexene 相应的烷-ane变成烯-ene
8.2 Nomenclature of alkenes and cycloalkenes H2 C C H CH3 IUPAC: Propene common; Propylene H2 C C CH3 CH3 IUPAC: 2-MethylPropene Common; Isobutylene Cyclohexane Cyclohexene 相 应 的 烷 -ane变 成 烯 -ene
The IUPAC rules for naming alkenes are similar in many respects to those for naming alkanes Selecting the longest chain that contains the double bond 2. Number the chain 23 234 6 H2C=CHCH2 CH3 CH3CH=CHCH2 CH2CH3 32 654321 1-Butene 2-Hexene (not 3-butene) (not 4-hexene
The IUPAC rules for naming alkenes are similar in many respects to those for naming alkanes 1. Selecting the longest chain that contains the double bond 2. Number the chain H2 C CHCH2 CH3 1-Butene (not 3-butene) 1 2 3 4 4 3 2 1 CH3 CH=CHCH2 CH2 CH3 1 2 3 4 5 6 6 5 4 3 2 1 2-Hexene (not 4-hexene)
3. Indicate the locations of the substituent groups CH CH 3 H3C—c=cHcH2CH3 CH2 C=CHCH CHCH 12345 123456 2-Methy1-2-pentene 2, 5-Dimethyl-2-hexene (not 4-Methyl-3-pentene) (not 2, 5-Dimethyl-4-hexene) CH3 H3C—c=cHcH2C—cH3 CHCH=CHCHbCI 4321 5, 5-Dimethyl-2-hexene 1-Chloro-2-butene (not 2, 2-Dimethyl-4-hexene) (not 4-chloro-2-butene)
3. Indicate the locations of the substituent groups C CHCH2CH3 2-Methyl-2-pentene (not 4-Methyl-3-pentene) CH3C=CHCH2CHCH3 1 2 3 4 5 6 2,5-Dimethyl-2-hexene (not 2,5-Dimethyl-4-hexene) CH3 H3C 1 2 3 4 5 CH3 CH3 C H CHCH2C 5,5-Dimethyl-2-hexene (not 2,2-Dimethyl-4-hexene) CH3CH=CHCH2Cl 4 3 2 1 1-Chloro-2-butene (not 4-chloro-2-butene) H3C 1 2 3 4 5 6 CH3 CH3 CH3
4. Number substituted cycloalkenes in the way that gives the carbon atoms of the double bond the 1-and 2 positions and that also gives the substituent groups the lower numbers at the first point of difference 1- Methylcyclopentane(1-甲基环戊烯)35 Dimethylcyclohexene(3,5二甲基环己烯) (not 2-methylcyclopentene) (not 4, 6-Dimethylcyclohexene)
4. Number substituted cycloalkenes in the way that gives the carbon atoms of the double bond the 1- and 2- positions and that also gives the substituent groups the lower numbers at the first point of difference 1-Methylcyclopentene (1-甲 基 环 戊 烯 ） (not 2-methylcyclopentene) 1 2 3 3,5-Dimethylcyclohexene (3,5-二 甲 基 环 己 烯 ） (not 4,6-Dimethylcyclohexene) 1 2 3 4 5