Isoamyl acetate preparation from reaction of vinyl acetate and Isoamyl alcohol catalyzed by H-ZSM-5 zeolite: a kinetic study

Abstract

Microporous H-ZSM-5 zeolite having good crystallinity and with the presence of Brønsted acid sites exclusively, was prepared by hydrothermal treatment of Expanded Perlite. The as-prepared H-ZSM-5 was used as heterogeneous catalyst for the reaction between vinyl acetate and isoamyl alcohol, as a greener alternative for the traditional preparation of isoamyl acetate. In this reaction, isoamyl acetate was generated by an acyl nucleophilic substitution mechanism, mediated by an acetylated zeolite complex, while acetaldehyde diisoamyl acetal has been produced as a secondary product due to a nucleophilic addition to acetaldehyde carbonyl carbon. The reaction was studied under different alcohol/ester molar ratio, supporting a second order kinetics when working under excess of one reactant. Moreover, an Eley-Rideal kinetic model has been suggested for a reaction mechanism of five steps, involving the ketalization of isoamyl alcohol and acetaldehyde as a parallel reaction that competes with transesterification.