Synergistic effect of Cu-Zn in mixed oxides derived from layered double hydroxides for the catalytic valorization of glycerol to glycerol carbonate

Abstract

Due to the interest in transforming the surplus glycerol generated in biodiesel production into valuable chemical products, such as glycerol carbonate, the catalytic transesterification of glycerol with dimethyl carbonate was studied to synthesize glycerol carbonate. Cu-Zn-Mg-Al mixed oxides with a variation of Cu-Zn were used as catalysts. These materials were obtained by calcination of their precursors, the layered double hydroxides, previously synthesized by co-precipitation, and were characterized physicochemically by XRD, MP-AES, N₂ sorption, SEM-EDS and DTP-CO₂. The best yield of glycerol carbonate was obtained with the catalyst with the highest Zn content, a result taken as background to modify parameters and find the optimal reaction conditions. The highest yield (82%) was obtained at 85 °C, 270 min, molar ratio DMC/glycerol=2, solvent-free and 7.5% by weight of catalyst; results attributed to the synergistic effect of Cu-Zn that promoted adequate basicity and textural properties.