Formation of the ester ethyl propanoate from a carboxylic acid

An acid anhydride is formed by removal of a molecule of water from two carboxylic acid molecules.

Ethanoic anhydride reacts with methanol to make the ester methyl ethanoate

• Describe the esterification of carboxylic acids with alcohols in the presence of an acid catalyst, and also of acid anhydrides with alcohols.

• Describe the hydrolysis of esters.

• State the uses of esters in perfumes and flavourings.

Esters

Acid hydrolysis of propyl ethanoate

Alkaline hydrolysis of ethyl propanoate

Wintergreen - ester methyl salicylate

Benzyl ethanoate