Direct dimethyl carbonate synthesis from CO2 and methanol over a flower-like CeO2 catalyst with 2-cyanopyridine as a dehydrating agent in continuous packed-bed reactor

A flower-like CeO₂ catalyst was successfully synthesized using an acrylamide graft copolymerized on glucose under hydrothermal conditions and used for the direct synthesis of dimethyl carbonate (DMC) from CO₂ and CH₃OH in a packed-bed reactor with 2-cyanopyridine as a dehydrating agent. The synthesized flower-like CeO₂ exhibited both basicity and acidity properties with values of 300 μmol g⁻¹ and 80 μmol g⁻¹, respectively, according to CO₂-TPD and NH₃-TPD results. The effect of reaction parameters such as reaction temperature, feed ratio, catalyst quantity, and operating pressure on the DMC production over the flower-like CeO₂ catalyst was investigated. The optimum conditions were found to be a temperature of 120 °C, catalyst weight of 1.0 g, CH₃OH : CO₂ ratio of 1 : 1, and pressure of 30 bar, which provided the highest CH₃OH conversion, DMC selectivity, and DMC yield of 86.6%, 99.3%, and 86.0%, respectively. Furthermore, no changes were observed in the structure, morphology, and particle size of the flower-like CeO₂ catalyst after the DMC synthesis reaction, indicating that the synthesized catalyst was resistant to the reaction test under such optimum reaction conditions.