Fischer Esterification involves the reaction between a carboxylic acid and an alcohol.

• Reaction: $R-COOH+R^{\prime }-OH\stackrel{H^{+}}{\rightleftharpoons }R-COO{R}^{\prime }+H_{2}O$
• Features: It is a reversible reaction catalyzed by an acid (usually concentrated $H_{2}S{O}_4$). To shift the equilibrium toward the ester (product), water is typically removed as it form.
• Isotopic labeling studies have shown that the '$O$' atom in the water molecule comes from the acid, while the '$-O{R}^{\prime }$ group comes from the alcohol.