Influence of Process Conditions on Glycerol Esterification Catalyzed by Tetra-NButylammonium-Modified Montmorillonite Catalyst

Abstract

Selective synthesis of glycerol monolaurate from glycerol and lauric acid was investigated. Loading of tetra-n-butylammonium modified montmorillonite catalyst (1-5 wt. %), reaction temperature (110-140 °C) and glycerol to lauric acid ratio (4:1 to 8:1) were used as variables and the performance was based on lauric acid conversion and glycerol monolaurate yield. Geometrical constraint in the pores retarded the formation of higher glycerides. Increasing catalyst loading improved the monolaurate yield. Fast reaction occurred within the first 8 h and 3 wt. % was deemed the optimum catalyst loading. No further benefit was achieved above 130 oC and 6:1 for the reactant ratio. Impressive lauric acid conversion of about 80 % with corresponding glycerol monolaurate yield of 70 % were achieved in 8 h at 130 °C, using a reactant ratio 6:1 and 3 wt. % of catalyst. The modified montmorillonite was therefore active and highly selective for the production of monolaurate