Abstract
Edible oil such has been used as raw material for biodiesel fuel (BDF). However, if the production of biofuel increases, it may compete with food and livestock feed and the price of oil may rise. Therefore, non-edible Jatropha curcas oil containing toxic phorbol esters has attracted attention. Recently a new BDF process which coproduct is not glycerin but triacetin has been developed. For triacetin can also be used as an anti-knock agent for biodiesel fuel, it is not necessary to remove triacetin from biodiesel fuel. The purpose of this study was to investigate the production of biodiesel fuel and reduction of toxic phorbol esters by transesterification of Jatropha curcas oil with methyl acetate. The formation of monoacetin, diacetin and triacetin was also confirmed by the spectrum estimated as the peaks of those substances. The peak of glycerin was not found among the major peaks of the chromatogram. As the molar ratio of methyl acetate to material oil was increased from 5 to 50, the yield of FAME was increased. The maximum FAME yield was 90 %. and the maximum concentration of FAME in the final product was 0.71 g/g. The concentration of phorbol esters in crude Jatropha curcas oil used in this study was 1.7 mg/g. The phorbol ester concentration of degummed oil decreased by a small amount from the crude oil. Phorbol esters decreased after deacidification and the concentration in phorbol esters in deacidified oil was 1.2 mg/g. The concentration in phorbol esters decreased to 0.22 mg/g after mixing step of oil with potassium methoxide. No phorbol esters were detected in any reaction time in the final product after the transesterification reaction in this study. The process used in this study is superior in that the phorbol ester contained in Jatropha curcas oil can be completely decomposed, compared with the conventional method using methanol as a raw material.
