Lipase-catalyzed synthesis of 2-ethylhexyl palmitate in a solvent free system using step changes in temperature

Abstract

Lipase-catalyzed synthesis of 2-ethylhexyl palmitate (2-EHP) from 2-ethylhexyl alcohol and palmitic acid was carried out in a solvent-free system. A commercial liquid lipase (Eversa Transform 2.0, Novozymes) from Thermomyces lanuginosus was immobilized on Lewatit VP OC 1600, a macroporous hydrophobic carrier. The efficacy of this Eversa immobilized lipase prepared in this study was evaluated on the synthesis of 2-EHP compared with that of Novozym 435 (from Candida antarctica), Lipozyme RM IM (from Rhizomucor miehei), Lipozyme TL IM (from Thermomyces lanuginosus), and the liquid Eversa lipase (commercial name: Eversa Transform 2.0). Among these lipases, the Eversa immobilized lipase was the most effective for the synthesis of 2-EHP. Optimum conditions for the synthesis of 2-EHP using this enzyme were a temperature of 55 °C and enzyme loading of 2% (based on the total weight of substrate). The conversion of 97% was achieved under these optimum conditions. Finally, as a cost-saving strategy, a step change in the reaction temperature was introduced. When a step change in the reaction temperature between 55 °C and 45 °C used, an identical degree of conversion was achieved compared to a constant reaction temperature of 55 °C throughout the reaction.