Transesterification of 2-o-Benzylglycerol with Vinyl Acetate by Immobilized Lipase: Study of Reaction and Deactivation Kinetics

摘要

The transesterification of 2-o-benzylglycerol with vinyl acetate has been studied in dichloromethane using free and immobilized lipase from Pseudomonas cepacia with particular emphasis on the effect of the pertinent variables and kinetic aspects of the reaction. The activity of the immobilized lipase was found to be maximum in the temperature range of 30-50 ℃, and it retained about one-third of the initial activity up to the third cycle after repeated use. The kinetics of the reaction was analysed by the so-called Ping Pong Bi Bi mechanism, and the model parameters were estimated by nonlinear regression analysis using Marquard's technique. The immobilized lipase, which had the activity in general, 3 times greater than that of the free lipase was deactivated by both temperature and vinyl acetate. The deactivation was found to be insignificant up to a certain level of vinyl acetate concentration above which, however the lipase activity fell rapidly. The deactivation kinetics was analysed by using a mathematical model which accounts for a series type of reaction mechanism.