Intrinsic Kinetics Resolution of an Enantioselective Transesterification Catalyzed with the Immobilized Enzyme Novozym435

Abstract

This work investigates the kinetics of the enantioselective transesterification of ethyl butyrate and (R)-2-pentanol in a solventless medium biocatalyzed by Novozym435, an immobilized Candida antarctica Lipase B. A reaction-diffusion reversible Ping-Pong bi-bi model was developed to represent the reaction rate with the additional estimation of the internal mass transfer using an orthogonal collocations method. A total of 18 experiments (774 data points) were realized in the SpinChem Vessel V2 batch reactor at a constant stirring speed of 400 rpm, varying temperatures (30–60 °C), component initial molar fraction (0.2–0.8), catalyst ratio (1–4% wt), and size fraction (200–1000 μm). Kinetics data were fitted using the model with a mean average percentage error of 3.45%, the 10 optimized kinetic parameters being coherent with the expected behavior of the Ping-Pong Michaelis–Menten mechanisms. Values for the effectiveness factor η for intraparticle mass transfer diffusion vary between 0.37 and 1, confirming the necessity to include mass transfer into kinetic modeling in our case.