LDH-catalyzed esterification of lauric acid with glycerol in solvent-free system

Abstract

Direct esterification of waste oil materials (high FFA contents) and glycerol can be an important way to improve the energy goals and afford alternative sources to emulsifier production for food and cosmetics industry. This work reports an experimental study of free-solvent esterification of lauric acid with glycerol using a LDH (layered double hydroxide, Mg–Al–CO3) as catalyst. The experiments were performed in a mechanically stirred reactor evaluating the effect of temperature (100–180°C), lauric acid to glycerol molar ratio (1:1–3:1) and catalyst content (2–8wt%). The results showed that relative high glycerol conversions (99%) can be obtained for the lauric acid esterification with glycerol leading to monolaurine and dilaurine. Results show that free-solvent LDH-catalyzed lauric acid esterification with glycerol might be a potential alternative route to conventional methods, as high contents of reaction products and selectivity was achieved. Furthermore, the results show that the LDH catalyst used was able to drive the reaction to the equilibrium in a relative short time – up to two hours.