‘Dry’ hydrolysis of nitriles effected by microwave heating

Abstract

The preparation of carboxylic acids from their corresponding nitriles by a ‘dry hydrolysis’ with dicarboxylic acids, in the absence of solvent, has been investigated. The reaction proceeds very slowly at atmospheric pressure, but high yields can be obtained in much shorter reaction times under pressure. The mechanism of the reaction has been studied and its rate constant and activation energy determined in the case of a model reaction (preparation of phenylacetic acid from benzyl cyanide with phthalic acid) under both microwave and conventional heating. No ‘microwave kinetic effect’ has been detected, but at high temperatures microwave heating gives better yields and selectivities.