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.

Abstract

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.