Synthesis of dimethyl carbonate from CO2 and methanol over CeO2: Role of copper as dopant and the use of methyl trichloroacetate as dehydrating agent

Abstract The effect of copper as dopant on ceria (CeO 2 ) was investigated in the direct synthesis of dimethyl carbonate (DMC) from CO 2 and methanol. Ceria with different copper loadings (0.02 and 0.5 wt%) was synthesized using the dry impregnation method and characterized by H 2 -TPR, XRD, EPR, UV–VIS/DRS, acid-base properties and N 2 physisorption. CeO 2 with 0.02 wt% of Cu showed the highest catalytic activity and selectivity to DMC, mostly due to its basic sites, associated with the presence of oxygen vacancies. Higher Cu concentration (0.5 wt%) promotes dehydrogenation, favoring the formation of methyl formate as the main product. Pure CeO 2 also produced dimethoxymethane as by-product. To circumvent the thermodynamic limitations of the reaction, methyl trichloroacetate was tested as dehydrating agent, showing superior performance than 2-cyanopyridine, due to its higher reactivity toward hydrolysis.