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
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:
1-methylcyclohexanol
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 product = most substituted
What are dehydration products of
1-methylcyclohexanol?
OH
CH3
H
Alcohols
Condensation Reaction
CH3 – OH + HO – CH3
H2SO4
CH3 – O – CH3 + H2O
two molecules combine to form
larger molecule + water
alcohol + alcohol
ether + H2O
Ethers
d-
R
water
alcohol
ether
H-bond acceptor Odno H-bond donor
dipole-dipole interactions
low b.p.
soluble in polar solvents
Ethers
Common nomenclature : name both R groups + ether
1
2
1
3
O
propyl
methyl
methyl propyl ether
methyl dimethyl ether
methyl
Ethers
Reactions
Formation:
H2SO4
condensation reaction
Peroxide formation:
peroxide