Kinetic study of lipase catalyzed asymmetric transesterification of mandelonitrile in solvent-free system

Optically active mandelonitrile was obtained by the lipase-catalyzed asymmetric transesterification of mandelonitrile in solvent-free system. The lipase Alcaligenes sp. was screened to be used in this system. Effects of various parameters were studied to deduce the kinetics and mechanism of the reaction. The optimal reaction temperature was 40 °C. The external diffusion limitation could be reduced greatly by raising the rotation speed and the internal diffusion could be ignored. The experimental results indicated that benzaldehyde and benzoic acid could greatly inhibit the enzyme activity. Using King–Altman method, a kinetic model of the transesterification of mandelonitrile with vinyl acetate in solvent-free system without substrate and production inhibition was proposed based on ping-pong bi–bi mechanism. Using Matlab program to simulate the processes and six parameters are obtained. The simulated values can fit the experimental values quite well and the relative error of the model was 8.61%.