Reaction pattern

Carboxylic acid + alcohol <-> ester + water. The reaction is reversible and uses an acid catalyst with gentle heating.

Named example

Ethanoic acid + ethanol <-> ethyl ethanoate + water. The alkyl part ethyl comes from ethanol and ethanoate comes from ethanoic acid.

Condensation idea

Water is eliminated when the ester linkage forms, so esterification is a condensation reaction. At this level, the detailed mechanism is not required.

Properties and observation

Many small esters have distinctive fruity smells and are used in flavourings, perfumes or solvents. Smell tests must use wafting and only when laboratory safety permits.

High-value recall and connections

Essential recall: What are the products of esterification? An ester and water. Name the ester from ethanol and ethanoic acid. Ethyl ethanoate. What catalyst is used? An acid catalyst. Practical connection: Warm a small carboxylic-acid/alcohol mixture with an acid catalyst in a water bath under teacher supervision and identify the product from the reactants. Examination connection: Name the ester alkyl first and alkanoate second.

Review questions and suggested answers