Recent progress on supported polyoxometalates for biodiesel synthesis via esterification and transesterification

Biodiesel is now recognized as a green fuel that has several advantages over conventional diesel. In the present review we discuss the catalytic esterification and transesterification reactions to the clean synthesis of biodiesel, over most readily investigated supported polyoxometalates to meet future societal demands. Here for the first time, we are reviewing biodiesel synthesis using supported lacunary polyoxometalates; also how the prevailing reaction conditions like reaction time, alcohol content, temperature, and catalyst amount affect the catalytic activity of the catalyst is discussed in detail. The new results for supported lacunary polyoxometalates are included where the effect of catalysts and supports was correlated with the catalytic activity.