Advancement in Catalysts for Transesterification in the Production of Biodiesel: A Review

Biodiesel is mono alkyl ester of long chain fatty acids derived from transesterification of triacyl glycerol present in renewable feed stocks such as vegetable oils and animal fats. Transesterification is a reversible process and proceeds appreciably by the addition of a catalyst. The catalysts can be homogenous, heterogeneous or enzymatic catalysts. It is affected by molar ratio of oil to alcohol, type and amount of catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats. The present review is an effort to give insight into the various catalysts used, their advantages and disadvantages in the context of biodiesel production.