Alcohols

1
Alcohols
organic analog of water
Hydrogen bond donor
O-Hd
Hydrogen bond acceptor
- 42oC
propane
boiling point
ethanol
78 oC
2
Alcohols
Solubility in H2O (g/100 mL)
formula
boiling point
C2H5OH 78 miscible C4H9OH 117 7.9
miscible
CH3OH
65
C6H13OH 158 0.5
C8H17OH 194 insoluble
d
d-
3
Alcohols - Nomenclature
1. Longest continuous chain with - OH 2. Root
name -ol 3. Position of - OH given smallest
number 4. Ring of cyclic alcohols numbered from
- OH 5. Compounds with more than one - OH
called diols or triols
4
Alcohols
heptan
ol
2
4
6
3-
4-ethyl-
1
7
3
5
2
4
1
3
5
diol
octane
2,4-
6-methyl-
6
7
8
phenol
5
classes of alcohols
1o alcohol
1
2
3
4
butanol
1-
2o alcohol
propanol
2-
3o alcohol
propanol
2-
2-methyl-
6
Alcohols
Classify and name
1o 2o 3o
cyclohexanol
1-methyl
1-propanol
1o
2-phenyl-
7
Alcohols - reactions
dehydration
reverse of hydration of alkenes
H2O
a) electrophile b) nucleophile
step 1
H


H
8
step 2

step 3
H
regenerate catalyst
9
hydration - dehydration
H
H2O
alcohol
Q
K 5
alkene
H2O
?G
-RT ln K/Q
10
4
1
2
3
2-butanol
4
3
1
3
1
2
2
4
2-butene
trans-
1-butene
major
minor
major product
most substituted
11
What are dehydration products of
1-methylcyclohexanol?
OH
a) major product b) minor product
CH3
H
major product
12
Oxidation of alcohols
Primary alcohols
1
2-
2-
1
2-
3
1-
1
1
1
1
2-
carboxylic acid
aldehyde
1o alcohol
O oxidizing agent
dichromate
Cr2O72-
Cr3
permanganate
MnO4-
1. binding O 2. removing H
oxidation
loss of e- density from C
13
Oxidation of alcohols
Secondary alcohols
no reaction
2o alcohol
ketone
14
Oxidation of alcohols
Tertiary alcohols
no reaction