Patent ID: 8907118

Claim:
A process for preparing an acyloxybenzoic acid of the formula (I) wherein R 1 is a linear or branched, saturated alkyl group having 6 to 30 carbon atoms, a linear or branched, singly or multiply unsaturated alkenyl group having 6 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms, comprising the steps of a) admixing para-hydroxybenzoic acid, in a solvent mixture comprising water and at least one organic solvent, with an alkali metal hydroxide, in an alkali metal hydroxide : para-hydroxybenzoic acid molar ratio ≧1.9:1 and only thereafter adding a carboxylic halide of formula R 1 COHal, in which R 1 is defined above and Hal is a halide, at a temperature ≦25° C., and carrying out reaction, b) adjusting the reaction mixture after step a), at a temperature ≦25° C., to a pH of 6 to 8.5 by addition of acid, if the pH at the end of step a) is not already within this range, c) subsequently heating the reaction mixture to a temperature of 35 to 80° C. and thereafter adjusting it to a pH of 1 to 4 by addition of acid, and e) adding the entire amount of alkali metal hydroxide in step a) before the addition of the carboxylic halide to the reaction mixture, and otherwise adding no further base in the process.