Low-temperature chemical synthesis of high-purity diacylglycerols (DAG) from monoacylglycerols (MAG).

A chemical method was developed for low-temperature synthesis of DAG from MAG followed by an easy purification procedure in order to obtain high-purity DAG. Solvent-assisted and solvent-free reaction conditions were used, combined with different catalysts (sodium methoxide, p-toluenesulfonic acid, methanesulfonic acid, and sulfuric acid). All reactions were performed at 35 and 70 °C. By increasing both acidity and polarity of the catalyst the equilibrium shifts towards the formation of DAG. When using sulfuric acid in solvent-assisted condition at 70 °C, 88% conversion was obtained after 20 min of reaction (77% w/w DAG in the reaction mixture after evaporation of the solvent). After purifying by means of column chromatography, 96% pure DAG were obtained. The overall yield of DAG was 81%.