Process for preparing aromatic hydroxy-carboxylic acid alkyl esters

Abstract

An improved process for the preparation of aromatic hydroxycarboxylic acid alkyl esters had been found which avoids working with organic solvents and especially avoids the formation of alkyl ether compounds by reaction of the dialkyl sulfate with the phenolic hydroxy groups. The final products are obtained in a high selectivity and with high yields. The novel process is carried out by esterification of an aromatic hydroxy-carboxylic acid with a dialkylsulfate in an aqueous medium at a pH-value in the range of from about 4 to 6.5, preferably at a temperature in the range of from 40.degree. to 80.degree. C, and it may advantageously be used as a subsequent reaction of a technically suitable carboxylation process of aromatic hydroxy compounds by esterification of its aromatic hydroxy-carboxylic acid final compounds.

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