18.2.1—Preparation of esters

An ester forms when an alcohol and carboxylic acid react in a condensation reaction. Concentrated H₂SO₄ catalyses the reversible process and water is eliminated.

Name the acid-derived alkyl and alcohol-derived alkyl parts, then balance the equation. Heating and removal of water can improve the ester yield, but equilibrium remains relevant.

Ethanoic acid + ethanol ⇌ ethyl ethanoate + water. The ester has the linkage CH₃COOCH₂CH₃ and a characteristic fruity smell.

The catalyst is not incorporated into the ester, and esterification is not the same as hydrolysis in reverse conditions.