Kinetics of the enzymatic alcoholysis of palm kernel oil in supercritical CO2

Recently, the use of supercritical CO2 (SCCO2) as a solvent in enzyme-catal yzed reactions has been a matter of considerable research because of its fa vorable transport properties that can accelerate mass-transfer-limited enzy matic reactions. Further, biocatalysts, especially lipases, have substrate speciff city and catalyze the syntheses of esters from a variety of acids a nd alcohols in SCCO2. Fatty acid esters obtained from alcoholysis of vegeta ble oils have many applications, such as antifriction agents, food preserva tives, and emulsifiers. However, despite the industrial importance of the p roducts obtained from alcoholysis of vegetable oils, conversions of such re actions in SCCO2 have hardly been reported in the literature. Hence, the ma in objective of this work is to study the ethanolysis of palm kernel oil in SCCO2 as catalyzed by two commercial Lipases. The experiments were perform ed in a reactor vessel in the temperature range of 40-70 degreesC and from 60 to 200 bar using a water concentration of 0-10 wt % and oil/ethanol mola r ratios fl om 1:3 to 1:10. The initial reaction rate was found to be a fun ction of both pressure and the oil/ethanol molar ratio. A simple model, cap able of representing the conversion-time relationship curve, is proposed.