(538v) Study on Catalytic Carbonylation of Glycerol with CO2 in Mild Condition over Cerium Oxide/Zinc Oxide Catalysts

In recent years, biodiesel has gained its popularity as an alternative fuel source due to its biodegradability and sustainability. However, with an increasing demand of the biodiesel, the byproduct during biodiesel production, i.e. glycerol, has been oversupplied. Therefore, seeking a process to transform glycerol to high-value products, such as glycerol carbonate and glycerol acetate, are needed. In this work, glycerol carbonate and glycerol acetate synthesized from glycerol and carbon dioxide over cerium oxide/zinc oxide (CeO₂/ZnO) as catalysts were attempted and studied. The catalysts were prepared with wet impregnation process to dope the pre-determined amount of Ce³⁺ on ZnO granules and followed by calcination at 500 ℃ for 6 hours. For convenience, x-y CeO₂/ZnO stands for the amount of CeO₂ doped is x wt% of the overall mass of CeO₂/ZnO catalyst. The catalysts were characterized by various instruments, including XRD, -adsorption, SEM-EDX, ICP-OES, and CO₂-TPD.

The carbonylation of glycerol with CO₂ in presence of dehydration agent, either acetonitrile (ACN) or 2-cyanopyridine (2-CP), was performed at 120 ℃ and 5 – 6 bar in a semi-batch system with a continuous CO₂ flow. With 10-90 CeO₂/ZnO, the yields of glycerol acetate near 2.55 % and glycerol carbonate at 18.8% could be achieve, as shown in Figure. In general, the yields of glycerol acetate and glycerol carbonate decrease as more cerium oxide were loaded onto (CeO₂/ZnO) as catalysts.