Ion-exchange resin catalysis in benign synthesis of perfumery grade p-cresylphenyl acetate from p-cresol and phenylacetic acid

Abstract

p-Cresylphenyl acetate is a very important perfume that finds wide applications and possesses an organoleptic character similar to those of honey, nuts, and butter. It is produced by mineral acid-catalyzed esterification of p-cresol with phenylacetic acid. Use of homogeneous acid catalysts leads to posttreatment pollution problems apart from the quality-related issues. The current work is focused with an eco-friendly and benign catalytic process, employing the solid acid catalysts such as dodecatungstophosphoric acid (DTP) supported on K-10 clay, ion-exchange resins, sulfated zirconia, etc. for esterification of p-cresol with phenylacetic acid to p-cresylphenyl acetate. The order of catalytic activity was found to be Amberlyst-15 ≈ Indion-125 > 20% w/w DTP/K-10 > sulfated zirconia. Indion-125 was used for further experiments. It was observed that the catalyst has excellent reusability and that the reaction was 100% selective towards p-cresylphenyl acetate. A pseudo-first-order kinetic model was built up to fit the experimental data, and the apparent activation energy was found to be 9.56 kcal/mol.