Synthesis of fatty acid monoglycerides from palm oil by glycerolysis with protected glycerol

Abstract

Fatty acid monoglycerides are used as emulsifers in the food, cosmetics, and detergents industries. Conventional routes of monoglyceride production are the direct esterification of glycerol with fatty acids or the transesterification of triglycerides. Since glycerol has three hydroxyl groups, the higher esters, such as diglycerides and triglycerides can also be simultaneously produced. To selectively produce monoglycerides, the protected glycerol having only one hydroxyl group available for transesterification is used instead of glycerol. Initially, two adjacent OH groups in glycerol are converted to the isopropylidene group; then the protected glycerol will be used in transesterification with triglycerides. Subsequently, the resulting monoglycerides will be deprotected. The products are identified by Fourier-Transform Infrared Spectroscopy (FT-IR) and High Performance Liquid Chromatography (HPLC) with and ultraviolet detector. As expected, the very high selectivity towards monoglycerides is obtained when the protected glycerol was utilized. The influence of protected glycerol to refine palm oil mass ratio and transesterification temperature on protected monoglycerides were also investigated. It observed that the protected monoglycerides content increased with the increasing mass ratio of protected glycerol to refined palm oil while other undesired esters decrease. Furthermore, the protected monoglycerides selectivity increases with transesterification temperature.