Studies on Mg–Ba mixed oxide catalysts for continuous glycerol transesterification to glycerol carbonate

Abstract

Mg–Ba mixed oxide catalysts are synthesized using the co-precipitation method by varying the molar compositions of MgO and BaO. The catalysts' surface/structural properties are characterized by N₂ physisorption, PXRD, CO₂-TPD, FT-IR spectroscopy, X-ray photoelectron spectroscopy, and laser Raman spectroscopy. The characterization results showed that the insertion of Mg²⁺ into the BaO lattice results in the generation of stable mixed oxide solid solutions. These catalysts are evaluated for continuous glycerol transesterification with dimethyl carbonate to yield glycerol carbonate under solvent free and atmospheric pressure conditions. The activity of catalysts mainly relied on strong basic centres (c-MgO) originating from Mg and Ba of different molar ratios and the catalyst with a 3 : 1 molar ratio exhibited an excellent glycerol carbonate yield of up to 70% with nearly 100% selectivity. The activities of the catalysts are well explained based on their surface-structural integrity. The catalysts exhibited exceptional stability during the time on stream study over a period of 100 h.