Mesoporous solid acid catalysts of 12-tungstosilicic acid anchored to SBA-15: Characterization and catalytic properties for esterification of oleic acid with methanol

12-tungstosilicic acid (HSiW) anchored to mesoporous molecular sieves SBA-15 was prepared and characterized for esterification of oleic acid with methanol. The influences of various HSiW loadings on their physicochemical properties were comparatively studied. The results showed that the as-prepared HSiW/SBA-15 retained the hexagonal mesoporous structure and the Keggin characteristic, although the textural parameters decreased with increasing loading of HSiW. The catalytic results showed that the environmentally benign mesoporous solid acid catalysts were efficient in the esterification of oleic acid for the synthesis of biodiesel. The catalyst with 30 wt.% HSiW loading exhibited the best activity under the reaction conditions.