Synthesis of Glycerides of Fatty Acids by Inorganic Solid Catalysts: A Review

Abstract

Homogeneous catalysts in the synthesis of mono- and di-glycerides have received wide acceptability due to their fast reaction rates. However, environmental issues and purification costs have led to the search for alternatives. Heterogeneous catalysts gained the attention of researchers because they can be applied to continuous processes, can be regenerated and can be used multiple times. This study reviews the available literature on solid catalysts used in the production of glycerides of fatty acids. It discusses the preparation methods, the reaction conditions and the results obtained in the three more important synthesis reactions: fatty acid esterification with glycerol, glycerolysis of fatty acid methyl ester and glycerolysis of triglycerides. The reported heterogeneous catalysts that were found to be the most active in the esterification reaction are the ones with strong acid sites. In the case of the glycerolysis, the most studied solid catalysts are Mg, Zn and Ca oxides, resulting in high monoglyceride yield.