(571b) Direct Carbonylation of Glycerol with CO2 to Organic Carbonates Catalyzed By Zinc Oxide/Zirconium Oxide

This study investigates the catalytic direct carbonylation of glycerol with CO₂ to produce glycerol carbonate. However, due to the high stability of both glycerol and CO₂, the reaction is difficult to proceed, requiring high-temperature and high-pressure conditions, which significantly increase equipment and operational costs [1, 2]. Several factors influence the reaction outcome, including reaction temperature, pressure, solvent ratio, and catalyst dosage. Typically, the carbonylation reactions in this work were carried out at 5 MPa CO₂ at 180°C with 2-cyanopyridine and ethanol as dehydrating agents, shown as Figure below.

ZnO/ZrO₂ catalysts were synthesized with the incipient wetness impregnation method to facilitate the reaction. Specifically, Zn(NO₃)₂·6H₂O was used as the precursor, while ZrO₂ served as the support. ZnO was loaded onto ZrO₂ via the wet impregnation method, forming a ZnO/ZrO₂ catalyst. The catalyst was characterized using various analytical techniques, including XRD, SEM, EDS, Nitrogen physisorption analyzer, CO₂-TPD, and ICP-OES. The yield of glycerol carbonate was adopted as the response variable, while the optimal reaction condition was sought via the response surface methodology (RSM) with a central composite design (CCD) [3]. Explicitly, a quadratic polynomial equation to describe the yield of glycerol carbonate was obtained by fitting the experimental data. The optimal condition was thus extracted from the established further verified with independent sets of experiments performed in the proximity to the optimal condition.

References:

[1] Liu, J. and D. He, Transformation of CO₂ with glycerol to glycerol carbonate by a novel ZnWO₄-ZnO catalyst. Journal of CO₂ Utilization, 26, 370-379 (2018).

[2] Lukato, S., Kasozi, G.N., Naziriwo, B., Tebandeke, E. Glycerol carbonylation with CO₂ to form glycerol carbonate: A review of recent developments and challenges. Current Research in Green and Sustainable Chemistry, 4, 100199 (2021).

[3] Montgomery, D.C., Design and Analysis of Experiments. 2012: Wiley.