abstract
- The authors thank Fundacção para a Ciência e Tecnologia (Portugal) for A.S.R.’s Ph.D. grant (SFRH/BD/13084/2003) and for the financial support of the project POCI/EQU/56732/2004, FEDER for financing LSRE (FEDER/POCI/2010), Professor Romualdo Salcedo from FEUP for the optimization code, and Novozymes and Amano Enzyme Inc. for kindly providing the catalysts.
- The kinetics of the lipase-catalyzed synthesis of decyl acetate, by the transesterification reaction of vinyl acetate with decanol, was investigated at 30 °C using n-hexane as the solvent. Novozym 435 was found to be the most active catalyst among the immobilized lipases tested. Given the nonideality of the reaction mixture, only a thermodynamic activity-based kinetics was found to be suitable to represent the experimental data in the entire range of compositions tested (0.1-1.4 M). The reaction follows a ping-pong bi-bi mechanism, in which inhibition only by excess of alcohol was identified. Although intraparticle diffusional limitations were detected, intrinsic kinetic parameters were obtained by crushing the catalyst particles. The results were compared to those obtained with supercritical CO2 as the solvent. For the conditions tested, Candida antarctica lipase B showed higher activity in the organic medium.