Reactivity of Triglycerides and Fatty Acids in Sub/Supercritical Dialkyl Carbonates for Biodiesel Production

Abstract

Recently, interest in dialkyl carbonates as an environmentally benign chemical for green chemistry is increasing but its utilization for biodiesel production in non-catalytic supercritical method has never been discussed earlier. Therefore, we studied the reactivity of triglycerides and fatty acids with several dialkyl carbonates in the non-catalytic sub/supercritical treatment in order to evaluate the potential of various dialkyl carbonates for the production of fatty acid alkyl esters (FAAE) and other value-added by-products. In batch-type and flow-type reaction systems, reaction condition was set at 300°C/20 MPa when dimethyl carbonate, diethyl carbonate, dipropyl carbonate and dibutyl carbonate have been utilized as reactants. The results showed that esterification of fatty acids proceeds at higher reaction rate than the interesterification of triglycerides in non-catalytic supercritical dialkyl carbonates. Shorter alkyl chains of dialkyl carbonates also showed higher reactivity than the longer ones. Based on the obtained results, potential of dialkyl carbonates for biodiesel production in non-catalytic supercritical process was discussed.

This work is an excerpt of PhD dissertation by Z. Ilham in Kyoto University who is presently in Institute of Biological Science, University of Malaya, Kuala Lumpur 50603, Malaysia.