13 Carboxylic acids.ppt

Chapter 13 Carboxylic acids
Nomenclature
Acidity of carboxylic acids
Factors affecting the acidity of
carboxylic acids
Dicarboxylic acids
Preparation of carboxylic acids
Preparation of carboxylic acids by
carbonation of Grignard reagents
Preparation of carboxylic acids by
the preparation and hydrolysis of
nitriles
Reactions of Carboxylic acids
Esterification
α-Halogenation of carboxylic acids:
Hell-Volhard-Zelinsky reaction
Decarboxylation of malonic acid
and pounds
Spectroscopic analysis of carboxylic
acids
Carboxylic acid:
Carboxyl group
(羧基)
Acyl group
(酰基)
All of carboxylic acid derivatives
contain the acyl group.
Nomenclature
1. e oic acid
4-Hexenoic acid
(4-己烯酸)
2-Hydroxy-2-
phenylethanoic
acid
Mandelic acid
(扁桃酸)
4-Methylhexanoic acid
(4-甲基己酸)
2. For pounds
with polyfunctional group carboxylic acids
outrank all mon group.
Ch. P281
P308
3-Bromocyclohexane-
carboxylic acid
(3-溴环己烷甲酸)
HY > RCOOH > H2CO3 >C6H5OH > H2O > RCH2OH >
pka: 4 ~ 5 10 16 ~ 19
~ 25 ~ 34 ~50
Acidity of carboxylic acids
sp2 hybridization,
p - πconjugation
3-Ethyl-6-methyl
octanedioic acid
(3-甲基-6-乙基
辛二酸)
1-Cyclopentene-
carboxylic acid
(1-环戊烯甲酸)
1
2
3
4
5
Stronger
base
Weaker
base
Weaker
acid
Stronger
acid
Sodium bicarbonate
RCOOH: Water insoluble;
RCOO-M+(Carboxylic salt): Water soluble
Carboxylic acids can be separated from
alcohols and phenol.
Factors affecting the acidity of
carboxylic acids:
Inductive effects of the substituents
pKa
With more electron-withdrawing groups,
acidity of the carboxylic acid is stronger.
Inductive effects fall off rapidly as number
ofσbond increases.
P313,
pKa:
2-Chlorobutanoic 3-Chlorobutanoic 4-Chlorobutanoic
acid acid acid
Carbon es more electron-
withdrawing as its s character increases:
sp3 < sp2 < sp
pKa:
Dicarboxylic acids:
Oxalic acid
(草酸或乙二酸)
Malon