Glyceride synthesis in a solvent-free system

Synthesis of partial glycerides in a solvent-free system has been investigated with various acyl donors and glycerol as substrates and a 1,3-specific immobilized lipase to catalyze the reaction. Capric acid was the most efficient acyl donor, compared with ethyl caprate and tricaprin. However, to obtain a high yield of dicaprin and a low amount of tricaprin, ethyl caprate was the acyl donor of choice. The composition of the product mixture was determined by the ratio of ethyl caprate to glycerol; a molar ratio of 3:1 was optimum for dicaprin synthesis. The water content in glycerol did not influence the final yield of dicaprin, but initial production of capric acid increased with increasing water content. The reaction was found to be controlled entirely by external mass transfer. The yield of diglyceride could be increased from 70 to 90% by lowering the reaction temperature, so that the diglyceride precipitated during the reaction.