Lipase‐catalyzed synthesis of butyl esters by direct esterification in solvent‐free system

Abstract

AbstractBACKGROUND:Reactions performed under solvent‐free conditions give processes that are environmentally friendly, since most solvents are polluting agents. In this work, the performance of Candida rugosa lipae (CRL) immobilized on styrene‐divinylbenzene (STY‐DVB) or controlled pore silica (CPS), and the commercial lipase Novozym 435, was evaluated for the synthesis of butyl esters in solvent–free systems (SFS). A 22 full factorial design was used to study the influence of the organic acid chain length and the biocatalyst concentration on the esterification performance.RESULTS:When CRL on STY‐DVB was used, the ester formation was influenced by both variables and their interaction. The reaction conversion was higher (63%) using 10% of immobilized system and lauric acid, corresponding to a productivity of 3.62 g L−1 h−1 For CRL on CPS, only the effect of biocatalyst concentration was significant, and the highest yield was attained using 20% of immobilized system and caprilic acid. In the case of Novozym 435, the highest yield (49%) was obtained using butyric acid as acyl donor at 15% of immobilized lipase.CONCLUSION:The results allowed better understanding of the influence of important parameters in this environmentally friendly process, which also has the process advantage of a higher volumetric productivity when compared with a solvent system. Copyright © 2007 Society of Chemical Industry