Biolubricant production in ionic liquids by enzymatic esterification

Abstract

Esterification of oleic acid with short carbon chain alcohols gives biofuels, with long chain alcohols biolubricants can be produced. Previously biolubricants was successfully produced from fusel oil and isoamyl-alcohol substrates by enzyme catalised esterification, but solution of polar substrates was problematic, that was solved by using ionic liquids. The optimal reaction parameters such as substrate molar ratios, initial water content, amount of enzyme and type of ionic liquid were determined by experimental design using Statistica software. Some of the ionic liquids have catalytic effect by itself, therefore control reactions were necessary to determine which ionic liquid has negligible catalytic effect. In five of the six investigated ionic liquid the yield was the same without enzyme, while in case of B[mim]PF6, the yield was negligible. In shorter time higher yield was achieved in presence of ionic liquid against other methods. Increasing the temperature results higher yield till a limit, higher temperature does not make moreproduct, but thermal desactivation of the enzyme was not occur.