Novel and Highly Efficient SnBr2-Catalyzed Esterification Reactions of Fatty Acids: The Notable Anion Ligand Effect

Abstract

In this work, the efficiency of Lewis acid catalysts, SnX2 (X = F−, Cl−, Br−, or −OAc), was investigated on the esterification reactions of fatty acids (i.e., myristic, palmitic, stearic, oleic, linoleic, and linoleic) with different alcohols (i.e., methyl, ethyl, propyl, isopropyl, and butyl alcohol). Tin(II) bromide was the most active catalyst in all reactions studied. We investigated the effects of main reaction parameters, such as catalyst concentration, temperature, and nature of alcohol and fatty acid. The highest activity of SnBr2 catalyst was discussed in terms of its lower activation energy, higher Lewis acid strength, and higher softness of anionic ligand. Finally, the SnBr2 catalyst can be easily recovered and reused without loss of catalytic activity. Effect of the tin catalyst nature on the oleic acid esterification with ethyl alcohol.