Noncatalytic biodiesel synthesis from rubber seed oil via supercritical methanol and ethanol

This paper reports the production of fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) by the transesterification reaction of rubber seed oil (RSO) in supercritical methanol and ethanol without using any catalyst. Experiment were carried out in a batch reactor, and reactions were studied at 260, 280, 300 and 320 oC at a pressure of 8.1-19 MPa with various mole ratios of ethanol – to - methanol from 0 to 100%. The extent of the reaction was explored using a convertibility parameter, which corresponds to the maximum ester content attainable from the feedstock. The highest FAME and FAEE contents achieved were 91.8 % and 86.4%, respectively. Results show that transesterification of RSO in methanol was more efficient than that in ethanol; the temperature had the strongest influence.