Fatty acid methyl ester synthesis over Fe3+vanadyl phosphate catalysts

A heterogeneous acid catalyst, Fe3+-vanadyl phosphate, prepared by the isomorphous substitution of some VO3+ groups in vanadyl phosphate with trivalent metal Fe3+, was found to be active for the transesterification of soybean oil with methanol. When the transesterification reaction was carried out with a molar ratio of methanol to oil of 30: 1, a reaction temperature of 473 K, a reaction time of 3 h and a catalyst amount of 5 wt%, the maximum conversion of soybean oil was 61.3%. Moreover, the catalytic activity of this catalyst was not significantly affected by the presence of free fatty acids and water in the reactants, and it also exhibits catalytic activity towards the esterification of free fatty acids with methanol. Further, it was shown that the spent catalyst could be easily reactivated by calcination at 773 K in air. There was very little change in the catalytic activity of the regenerated catalyst, even after five cycles.