Esters are produced by the esterification of carboxylic acid with alcohol in the presence of an acid catalyst. This process is essentially a condensation reaction in which a molecule of water is released along with the formation of the ester.
For example consider the reaction of acetic acid (CH3COOH) with methanol (CH3OH):
CH3COOH + HOCH3 → CH3COOCH3 + H2O
The product formed is acetoacetic ester along with a molecule of water.
