Eco-Friendly Production of Fatty Amides Using 1-Monoacylglycerols as Acyl Donors

Abstract

An efficient and environmentally friendly method to produce fatty amides by enzymatic amidation with 1-monoacylglycerols (MAGs) as acyl donors is described. When 1-monoolein was employed as a fatty donor to synthesize oleoyl ethanolamide, the product yield was up to 96% under optimum conditions. Subsequently, a comparative study using various acyl donors including 1-monoolein, oleic acid, triolein, and ethyl oleate was performed. The results displayed that 96.2, 76.4, 0, and 51.8% oleoyl ethanolamide were formed, respectively. Additionally, a two-step method was developed to prepare fatty ethanolamide with vegetable oil as a substrate. The results demonstrated that excess glycerol had a significant effect on lipase stability and a 3 h glycerolysis and a 3 h amidation resulted in the formation of 95.2% fatty ethanolamide. Last, various fatty amides were synthesized with MAGs as substrates. The results showed MAGs were equally effective reactants for the preparation of other amides. This was the first study reporting the use of MAGs as acyl donors to prepare fatty amides. MAGs are safer substrates compared to toxic fatty acid chlorides and fatty acid vinyl esters. In conclusion, a greener approach is developed for fatty amide preparation and the method is more efficient than those using other acyl donors.