Transcript CARBOXYLIC ACIDS

Halogen
+
NaOH
O
C
R
CH3
solvent
then H+
R
O
H
C
C
OH
X
X
X
Since carboxyl group consists of carbonyl and hydroxyl groups, it is expected
that acids show reactions due to both these groups. However the reactions
expected of these groups are modified as a result of interaction between these
groups due to close proximity.
Carboxylic acids are resonance hybrid of the following structures.
It is clear that the carbonyl part of the carboxyl group does not have a double
bond character but a reduced double bond character. Thus it does not give the
reactions of the carbonyl group. The carbonyl carbon in carboxyl group is less
electrophilic than the carbonyl carbon in aldehydes and ketones due to
resonance. Therefore many nucleophilic addition reactions of aldehydes and
ketones do not take place with carboxylic acids. The same effect makes the
hydroxyl group of carboxylic acids more acidic than the hydroxyl group of
alcohols and phenols justifying why they are called acids.
A
B
COOH
A
B
A
B
COOH
COOH
A
A
B
COOH
B
COOH
HO
HO
HO
NO 2
O 2N
NO 2