Kinetic study of the enzymatic synthesis of 2-phenylethyl acetate in discontinuous tank reactor

Abstract

There is increasing interest in new processes to produce aromatics labeled as “natural” and, as a consequence, enzymatic processes, in some organic solvent or in solvent-free medium, have been developed. This paper offers a kinetic study of lipase-catalyzed transesterification for synthesizing 2-phenyl-ethyl acetate in a batch reactor, using Novozym® 435 and hexane as solvent. Influence of five variables on the conversion is studied. A pseudo-first order kinetic model, derived as a simplification of a Bisubstrate Ping-Pong kinetics, is presented. The amount of catalyst was the variable most affecting kinetic and yield, while initial substrate concentration had little effect on the reaction kinetic. Yield increased gradually as the molar ratio increased, and was more pronounced with vinyl acetate than 2-phenethyl alcohol. Michaelis constants of both substrates and maximum reaction rate, for the range of assayed experimental conditions of temperature, stirring speed and enzyme concentration, were determined and compared with others in the literature. Finally, the proposed kinetic model was validated with high correlation coefficients.