Download Review - Alkenes

Alcohols
organic analog of water
Hydrogen bond donor O-Hd+
.. dHydrogen bond acceptor O
..
boiling point
propane
- 42oC
ethanol
+ 78 oC
Alcohols
formula
boiling point
CH3OH
C2H5OH
C4H9OH
C6H13OH
C8H17OH
H3C
Od
H3C
65
78
117
158
194
H
d
miscible
miscible
7.9
0.5
insoluble
O-
d+
O-
Solubility in H2O
(g/100 mL)
d
d+
H
+
d
H
CH2CH2CH3 H
CH2
O
H
CH2CH2CH2 H23C
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”
Alcohols
7
6 5 4 3 2
5 4
6
7
1
3 2 1
4-ethyl-3- heptan ol
6-methyl- 2,4- octane diol
8
phenol
classes of alcohols
4
3
2
1
1o alcohol
1- butanol
2o alcohol
2- propanol
3o alcohol
2-methyl-2- propanol
Alcohols
Classify and name:
1o
2o 1-methylcyclohexanol
3o
1o 2-phenyl-1-propanol
Alcohols - reactions
dehydration reverse of hydration of alkenes
H
H
H
C
C H
H
OH
H
H
C
C
H
step 1
H
H
H
C
C H
H+
H
H
a) electrophile
b) nucleophile
H
H
C
C H
H O
H
H
:
:
H : OH
H+
+ H2O
H
C
C H
step 2
H
H O
H
H
H
H
C
C H +
:
H
step 3
H
H
C
H
C
+ H+
H
regenerate catalyst
H
: :
H
H
O
H
hydration - dehydration
+ H2O
H+
[alcohol]
Q=
[alkene] [H2O]
G = -RT ln K/Q
K=5
1
2
3
4
2-butanol
H
H
C
1
C
H
2
3
C H
H
1-butene
4
CH3
H3C
1
2
C
3
C
H
4
CH3
H
trans- 2-butene
major
minor
major product = most substituted
What are dehydration products of
1-methylcyclohexanol?
OH
CH3
a) major product
b) minor product
H
H
major product
Oxidation of alcohols
Primary alcohols:
1+
1-
2- 1+
1+
1o alcohol
1+
2-
3+
1+
aldehyde
2-
2- 1+
carboxylic acid
[O] = oxidizing agent dichromate
permanganate
Cr2O72- Cr3+
MnO4-
oxidation = loss of e- density from C 1. binding O
2. removing H
Oxidation of alcohols
Secondary alcohols:
no reaction
2o alcohol
ketone
Oxidation of alcohols
Tertiary alcohols:
no reaction