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The lipase-catalysed optical resolution of a racemic mixture of 2-methyl-1-pentanol by transesterification using vinyl acetate as acyl donor has been studied experimentally. A mechanistic model has been developed for the double-substrate reaction sequence treating both enantiomers as competing substrates. The model is based upon a ping-pong mechanism with alternative substrates involving an acyl-enzyme intermediate. The kinetic constants of the model have been evaluated using initial rate experiments and nonlinear regression analysis. The model successfully predicts the evolution of the enantiomeric excess of substrate (eeR) and the degree of conversion with time for batch experiments with various initial concentrations of vinyl acetate and (R,S)-2-methyl-l-pentanol. Furthermore, the rate equations have been used to theoretically study the dynamic progression of a continuous enzyme-catalysed resolution process. The enantiomeric excess as a function of conversion for different process configurations is discussed. It is found, that the maximum attainable eeR is strongly dependent on the residence time distribution of the continuous reactor and is rather low for a continuous stirred tank reactor (CSTR) due to competitive inhibition effects.KEY WORDS Enzyme kinetics, mathematical modelling, optical resolution, lipase, 2-methyl-lpentanol. LIST OF SYMBOLS

A continuously stirred tank reactor equipped with a microfiltration membrane unit for effective retention of solid enzyme particles in organic solvent systems was constructed. A microfiltration membrane with pore size 0.1 μm based on a polypropylene matrice was used for enzyme retention and showed no loss of performance or denaturation by the organic solvent. The stereoselective transesterification reaction of (±)‐trans‐sobrerol with vinyl acetate as both acyl donor and solvent was chosen as a model system. Lipase PS from Pseudomonas sp. was used in its native form without further modification steps and remained active and highly stereoselective at 50 °C when applied to the reaction system for about 600 h of continuous operation. (‐‐)‐(1S,5R)‐sobrerolacetate and (+)‐(1R,5S)‐sobrerol could be obtained in the reactor outlet stream at approximately 48% conversion with enantiomeric excesses eeP ≈︁ 92% and eeS≈︁ 80%, respectively. Furthermore, theoretical kinetic studies showed that limitations in enantiomeric purity due to the characteristics of an ideal mixed tank may be sufficiently overcome by designing a simple two‐stage process.

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