Chemistry Reference
In-Depth Information
ESTERS
Esters are the reaction product of an acid and an alcohol with the simulta-
neous formation of water.
Some esters with fruity odors:
CH
3
COOC
4
H
9
butyl acetate
pear
CH
3
COO(CH
2
)
2
CH(CH
3
)
2
isoamyl acetate
banana
CH
3
CH
2
COOCH
2
CH(CH
3
)
2
isobutyl propionate
rum
C
3
H
7
COOC
4
H
9
butyl butyrate
pineapple
Note that ester names contain first the alcohol, then the acid portion and end
in -
ate
. Thus, the ester from the reaction of ethanol with acetic acid is called
ethyl acetate.
The whole range of carboxylic acids and alcohols can be reacted to form
esters. They are found in a large number of natural and synthetic scents and
perfumes because of their pleasant odor. Many are used as solvents for paints
and resins. Esters are converted back into the original acids and alcohols by
reaction with strong bases in water in a process called
saponification
(soap
formation),
RCOONa
RCOOCH
2
CH
2
OH
CHOH
CH
2
OH
H
2
O
+ NaOH
R'COONa
+
R'COOCH
R''COONa
R''COOCH
2
fat
soaps
glycerine
or by
hydrolysis
(which means splitting by water).
CH
3
COOC
2
H
5
+
H
2
O
CH
3
COOH
+
CH
3
CH
2
OH
