110 likes | 223 Views
Chapter 12. Alkenes and Alkynes Geometric Isomers of Alkenes. Saturated and Unsaturated Compounds. Saturated compounds (alkanes) have the maximum number of hydrogen atoms attached to each carbon atom Unsaturated compounds have fewer hydrogen atoms attached to the carbon chain than alkanes
E N D
Chapter 12 Alkenes and Alkynes Geometric Isomers of Alkenes
Saturated and Unsaturated Compounds • Saturated compounds (alkanes) have the maximum number of hydrogen atoms attached to each carbon atom • Unsaturated compounds have fewer hydrogen atoms attached to the carbon chain than alkanes • Unsaturated compounds contain double or triple bonds
Alkenes • Carbon-carbon double bonds • Names end in -ene H2C=CH2 ethene (ethylene) H2C=CH-CH3 propene (propylene) cyclohexene
Alkynes • Carbon-carbon triple bonds • Names end in -yne HCCH ethyne(acetylene) HCC-CH3 propyne
Naming Alkenes and Alkynes When the carbon chain has 4 or more C atoms, number the chain to give the lowest number to the double or triple bond. 1 2 3 4 CH2=CHCH2CH3 1-butene CH3CH=CHCH3 2-butene CH3CCCH3 2-butyne
Naming Alkenes and Alkynes Name and number all groups bonded to the parent alkene or alkyne, and place the name and number in front of the name of the parent compound. 1 2 3 4 CH3C=CHCH3 2-chloro-2-butene Cl
You Try These! Write the IUPAC name for each of the following unsaturated compounds: A. CH3CH2CCCH3 CH3 B. CH3C=CHCH3 C.
Answers to You Try These! Write the IUPAC name for each of the following unsaturated compounds: A. CH3CH2CCCH3 2-pentyne CH3 B. CH3C=CHCH3 C. 2-methyl-2-butene 3-methylcyclopentene
Naming Alkenes and Alkynes If more than one double or triple bond is present, indicate the position of each and use one of the suffixes –diene, -triene, and so on. • CH2=C-CH=CH2 2-methyl-1,3-butadiene CH3
Cis and Trans Isomers • Double bond is fixed • Cis/trans Isomers are possible CH3 CH3 CH3 CH = CH CH = CH cis trans CH3