Application of Phosphonium- and Choline Chloride Based Deep Eutectic Solvents as Catalyst for Emulsifier Production from Low Quality Oil Assisted by Microwave Irradiation

Abstract

Monoglycerides (MAG) and Diglycerides (DAG) have wide applications in the food, pharmaceutical and cosmetic industries. Despite the economic competitiveness of producing this type of emulsifier from vegetable oils, the increasing demand for products with high nutritional value makes certain types of healthy oils such as rice bran oil (RBO) a potential raw material for high quality fats to serve this growing market. However, the high free fatty acids (FFA) and RBO content which is insoluble in acetone make it difficult to process and is categorized as a low-quality oil, causing RBO to be only used as biodiesel feedstock. Enzymatic catalytic route for glycerolysis of vegetable oil offers milder operating conditions and higher product selectivity (MAG) but it has high production costs and long processing time. In this study, biodegradable catalysts were used, namely deep eutectic solvents (DES) based on phosponium and choline chloride for glycerolysis of dewaxed/degummed RBO (DDRBO) assisted with microwave irradiation. Effects of different types of DES catalysts (phosphonium and choline chloride based DES) on DES-catalyzed glycerolysis of low quality oil will be evaluated using 5%wt of DES, 300 W(150°C) for about 15 minutes. Out of the four DESs used, DES [TBAB][PTSAM] and DES [ChCl][AcAd] both showed outstanding catalytic performance. Especially [ChCl][AcAd] as a reaction catalyst for DDRBO glycerolysis showed the best catalytic activity, and high selectivity for the formation of monoglycerides (MG). Meanwhile [TBAB][PTSAM] showed high selectivity (92.57%) for diglyceride (DG) formation.