Production of glycerol carbonate from glycerol and carbon dioxide using metal oxide catalysts

This work is focused on a green production of glycerol carbonate through converting glycerol, as a by-product of biodiesel production, and a greenhouse gas, carbon dioxide, using metal oxide catalysts of MgO, CaO, and Al2O3. The catalysts were prepared by precipitation method and characterized by surface area and pore size, TGA, XRD, CO2-TPD, and SEM analyses. The catalysts' performance was mostly influenced by the number of basic sites and the BET surface area of the catalysts. The catalysts' activity results displayed that MgO showed the highest glycerol conversion of 22.7% and the highest yield of 10.6% among the investigated catalysts. The turnover number of the optimum catalyst was 14.9 μmol glycerol carbonate/μmol CO2. The effect of reaction parameters on the performance of the reaction was also investigated and the highest glycerol carbonate yield of 12.76 % was achieved at a catalyst loading of 5.5 wt% of glycerol amount, the temperature of 150 ⁰C, and pressure of 8 MPa. The physicochemical properties of catalysts were correlated with their activities and abilities for CO2 activation.