Chemistry Reference
In-Depth Information
-
K
+
O
2
N
OH
+
KOH
O
2
N
O
+
H
2
O
b.
Alcohols do not react with aqueous base. The equilibrium favors the starting
material because hydroxide ion is a weaker base than the alkoxide ion:
H
H
+
+
H
H
2
O
_
K
+
OH
O
7.14
Write the structure of the alcohol, and consider products with a double bond between
the hydroxyl-bearing carbon and each adjacent carbon that also have at least one
hydrogen attached.
a.
CH
3
H
3
C
CH
3
H
2
O
H
+
CC
CH
3
CH
2
C
CH
2
CH
3
H
CH
2
CH
3
OH
+
H
CH
3
CH
2
+
CC
C
H
3
C
CH
2
CH
3
CH
3
CH
2
CH
2
CH
3
b.
OH
H
2
H
+
O
+
CH
3
CH
2
CH
3
The predominant product is generally the alkene with the most substituted double
bond. In part a, the products with trisubstituted double bonds should predominate over
the disubstituted product. To predict more precisely is not possible. In part b, the
product with the double bond in the ring (1-methylcyclohexene) is trisubstituted and will
predominate.
7.15
Unlike the alcohol in Example 7.2, the alcohol in this case is primary instead of tertiary.
The rate-determining step is the S
N
2 reaction:
X
_
S
N
2
slow
step
CH
3
(C H
2
)
3
X
CH
3
(CH
2
)
3
OH
+
H
+
CH
3
CH
2
CH
2
CH
2
O
H
+
+
H
2
O
H
The rate of this step varies with the nucleophilicity of X
-
; this order of nucleophilicity is
I
-
> Br
-
> Cl
-
.
7.16
a.
CH
3
CH
3
+
2
O
+
r
Br
OH
b.
OH
+
r
+
2
O
Br
