Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol over CexZr1-xO2 and [EMIM]Br/Ce0.5Zr0.5O2

Abstract

The solid solution series CexZr1-xO2 (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0) with a bimodal pore structure was prepared by the citric acid sol−gel method. Results from X-ray diffraction, Raman spectroscopy, scanning electron microscopy, mercury porosimetry, and N2 adsorption/desorption measurements indicated that the physical properties of the solid solutions were significantly affected by the Ce/Zr molar ratio and the calcination temperatures. These solid solutions can be used in the synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide. Results indicated that the structure of the solid solutions and the Ce/Zr molar ratio in CexZr1-xO2 were the key factor in determining the catalytic activity for the synthesis of DMC. Higher catalytic performance was observed with a 1:1 Ce/Zr molar ratio at a calcination temperature of 1273 K. 1,1,1-Trimethoxymethane (TMM) was used to remove residual H2O in situ, and was found to increase the methanol conversion from 1.8 to 7.9% at 373 K under a pressure...