Promotional effect of calcination temperature on structural evolution, basicity, and activity of oil palm empty fruit bunch derived catalyst for glycerol carbonate synthesis

Abstract

The synthesis of glycerol carbonate (GC) from glycerol and dimethyl carbonate (DMC) catalyzed by oil palm empty fruit bunch ash (EFBA) was developed in this work. The catalyst was calcined at a temperature range of 300–600 °C, and the effect of temperature was correlated with the catalyst structure-activity relationship, the total basicity, and basic strength. The catalyst characteristics were investigated by the N2-adsorption-desorption, Fourier transform infrared, FTIR, X-ray diffraction, XRD, and Scanning electron microscope and energy dispersive spectroscopy, SEM/EDS. The results show that increasing calcination temperature propagates crystalline phase transition from KAlSiO4 to K2Mg(SiO4) by incorporating more K+ in the tetrahedral framework of SiO2 connected with Mg2+O4. Consequently, catalyst basic strength was enhanced and a significant amount of basic sites was generated with a corresponding increase in the GC yield. Also, the reaction temperature, initial DMC/glycerol molar ratio, catalyst dosage, and reaction time influence the yield of GC. Hence, 95.7% GC yield was achieved under 5 wt.% catalyst concentration, 90 °C, and initial DMC/glycerol molar ratio of 3:1 under 45 min reaction time. The catalyst sustained 85.2% GC yield after four times reuse, indicating relatively high stability without severe deactivation.