Chapter 17: Alcohols and Phenols
Chapter 17: Alcohols and Phenols
C O O H H
sp3
alcohol pKa~ 16-18
phenol (aromatic alcohol) pKa~ 10
Alcohols contain an OH group connected to a saturated carbon (sp3) Phenols contain an OH group connected to a carbon of a benzene ring
O H C C
H C C
O
chemistry dominated by the keto form
76
enol
keto
H
O
H
R
O
H
R
O
R
R
O
O
R'
water
alcohol
R S H
ether
R S R
peroxide
R S S R'
thiols
thioether
disulfides
Alcohols are classified as primary (1°), secondary (2°) or tertiary (3°), which refers to the carbon bearing the hydroxy group
methanol
H C O H H H
primary
R C O H H H
secondary
R C O R H H
tertiary
R C O R R H
77
1° carbon
2° carbon
3° carbon
39
17.1: Nomenclature: 1. In general, alcohols are named in the same manner as alkanes; replace the -ane suffix for alkanes with an -ol for alcohols
CH 3CH 2CH 2CH 3 CH 3CH 2CH 2CH 2OH OH
butane
1-butanol
2-butanol
2. Number the carbon chain so that the hydroxyl group gets the lowest number 3. Number the substituents and write the name listing the substituents in alphabetical order. 4. For phenols, follow benzene nomenclature and use phenol as the parent name. The carbon bearing the -OH group gets number 1. 78
OH
OH OH NO2 NO2
2-methyl-2-pentanol
3-phenyl-2-butanol
3,4-dinitrophenol
Many alcohols are named using non-systematic nomenclature
OH
OH
H3C C OH H3C H3C
OH HO OH HO OH
benzyl alcohol (phenylmethanol)
allyl alcohol (2-propen-1-ol)
tert-butyl alcohol (2-methyl-2-propanol)
ethylene glycol (1,2-ethanediol)
glycerol (1,2,3-propanetriol)
79
40
17.2: Properties of alcohols and phenols: Hydrogen bonding: The structure around the oxygen atom of an alcohol or phenol is similar to that in water and is sp3 hybridized Alcohols and phenols have much higher boiling points than similar alkanes and alkyl halides
H2 O MW=18 bp= 100° C C6H6
C O O H H
sp3
alcohol pKa~ 16-18
phenol (aromatic alcohol) pKa~ 10
Alcohols contain an OH group connected to a saturated carbon (sp3) Phenols contain an OH group connected to a carbon of a benzene ring
O H C C
H C C
O
chemistry dominated by the keto form
76
enol
keto
H
O
H
R
O
H
R
O
R
R
O
O
R'
water
alcohol
R S H
ether
R S R
peroxide
R S S R'
thiols
thioether
disulfides
Alcohols are classified as primary (1°), secondary (2°) or tertiary (3°), which refers to the carbon bearing the hydroxy group
methanol
H C O H H H
primary
R C O H H H
secondary
R C O R H H
tertiary
R C O R R H
77
1° carbon
2° carbon
3° carbon
39
17.1: Nomenclature: 1. In general, alcohols are named in the same manner as alkanes; replace the -ane suffix for alkanes with an -ol for alcohols
CH 3CH 2CH 2CH 3 CH 3CH 2CH 2CH 2OH OH
butane
1-butanol
2-butanol
2. Number the carbon chain so that the hydroxyl group gets the lowest number 3. Number the substituents and write the name listing the substituents in alphabetical order. 4. For phenols, follow benzene nomenclature and use phenol as the parent name. The carbon bearing the -OH group gets number 1. 78
OH
OH OH NO2 NO2
2-methyl-2-pentanol
3-phenyl-2-butanol
3,4-dinitrophenol
Many alcohols are named using non-systematic nomenclature
OH
OH
H3C C OH H3C H3C
OH HO OH HO OH
benzyl alcohol (phenylmethanol)
allyl alcohol (2-propen-1-ol)
tert-butyl alcohol (2-methyl-2-propanol)
ethylene glycol (1,2-ethanediol)
glycerol (1,2,3-propanetriol)
79
40
17.2: Properties of alcohols and phenols: Hydrogen bonding: The structure around the oxygen atom of an alcohol or phenol is similar to that in water and is sp3 hybridized Alcohols and phenols have much higher boiling points than similar alkanes and alkyl halides
H2 O MW=18 bp= 100° C C6H6