Illustrated Glossary of Organic Chemistry

Esterification: A reaction which produces an ester. The reaction often involves an alcohol and a Bronsted acid (such as a carboxylic acid, sulfuric acid, or phosphoric acid).

In this example of the Fischer esterification reaction, benzoic acid (a carboxylic acid; the reactant shown in red) is esterified with methanol (an alcohol, the reaction solvent, and the reactant shown in blue) in the presence of sulfuric acid (an acid catalyst) to form methyl benzoate (an ester). Water, the other reaction product, is removed as formed in order to shift the reaction equilibrium towards the products (via Le Chatelier's principle).

The first step in glycolysis is an esterification reaction. Phosphorylation of glucose with ATP and hexokinase (an enzyme) gives glucose-6-phosphate, a phosphate ester.