Green and facile synthesis of glycerol carbonate from bio-glycerol assisted by lithium titanate: A robust and selective heterogeneous catalyst

Glycerol carbonate, an essential value-added product obtained from biodiesel byproducts, has diverse utilizations in pharmaceuticals, food, cosmetics, and chemical industries. The high price of glycerol carbonate constrains its remarkable applications; thus, research society has effectively focused on the synthesis of such compounds. A highly efficient heterogeneous catalyst Li/TiO2 was synthesized via the wetness impregnation method and applied for transesterification of glycerol with DMC to afford glycerol carbonate. The designed catalyst was studied by performing various characterization techniques such as XRD, TGA-DTA, XPS, FT-IR, FESEMEDAX, HR-TEM and ICP-MS analysis to obtain its physicochemical properties. 1H and 13C NMR spectroscopic methods were performed to determine the conversion of glycerol-to-glycerol carbonate. The reaction parameters were also optimized, and the best conversion was obtained at a 1:3 molar ratio of Glycerol and DMC, 90 °C reaction temperature, 2 h’ reaction time, 500 rpm agitation speed and at 5 weight % catalyst loading. The highest conversion obtained was 95.5%, with a selectivity of 95.9% towards glycerol carbonate. These studies shows Li/TiO2 as an efficient catalyst for transesterification of glycerol to glycerol carbonate. Reusability study established that 25 wt.% Li/TiO2 catalyst can be successfully run for successive five catalytic cycles with effective glycerol conversion.