HClO₄-SiO₂ Catalyst for Esterification of Carboxylic Acids with Alcohols

Significance

A novel efficient protocol for the esterification of carboxylic acids with alcohols using perchloric acid immobilized on silica gel (HClO₄-SiO₂) was described. The direct condensation of carboxylic acids with alcohols under solvent-free conditions in the presence of HClO₄-SiO₂ gave the corresponding esters (55 examples, 52-98% yield). The catalyst was reused four times (yields of one ester: 1^st use: 92%, 2^nd use: 92%, 3^rd use: 90%, 4^th use: 83%, 5^th use: 80%).