Esters

- An ester is a condensation product of an acid and an alcohol.
- The formation of an ester from an acid and an alcohol is
termed esterification.
- During esterification a molecule of water is eliminated.
- The formation of an ester from the acid and alcohol requires
the use of heat and a dehydrating agent like conc. sulfuric acid.
(Is there a difference between a dehydrating agent and a drying
agent?)
- Most esters are pleasant smelling compounds and are useful
as constituents of perfumes, cosmetics and food flavouring agents.
- Many esters are of medicinal importance.
- Methylsalicylate is a constituent of many ointments like
Vicks, Amrutanjan, Tiger Balm, Bengay and so on. (It is a muscle
relaxant). Here is a list of some esters, their odours, the acid
and alcohol from which they are derived.
| Acid |
Alcohol |
Ester |
Smell |
| Acetic acid
|
Benzyl alcohol |
Benzyl acetate |
Jasmine |
| Butyric acid |
Methyl alcohol |
Methyl butyrate |
Apple |
| Butyric acid |
Ethyl alcohol |
Ethyl butyrate |
Pineapple |
| Acetic acid |
Isoamyl alcohol |
Isoamyl acetate |
banana |
| Anthranilic acid |
Methyl alcohol |
Methyl anthranilate |
grapes |
| Salicylic acid |
Methyl alcohol |
Methyl salicylate |
oil of wintergreen (Vicks) |
|