Direct synthesis of dimethyl carbonate on H3PO4 modified V2O5

The catalytic properties of modified V2O5 catalysts for the dimethyl carbonate (DMC) synthesis from CO2 and CH3OH were investigated. Experimental results showed that the modified V2O5 catalysts were effective for the direct and selective synthesis of DMC from carbon dioxide and methanol. The characterization of modified V2O5 catalysts was performed by means of X-ray diffraction (XRD), thermogravimetric (TG) and diffuse reflectance FTIR (DRIFT) spectra. XRD patterns showed that the crystal phase changed from orthorhombic to orthorhombic-tetragonal double phase. TG results showed that the weaker acid sites increased when V2O5 was treated with varying H3PO4 contents. DRIFT spectra of the CO2 and CH3OH absorbed on catalysts indicated that both CO2 and CH3OH were effectively activated on the catalysts. Finally, the experiment results demonstrated that the crystal phase of the catalyst influenced greatly on the reaction yield and selectivity of DMC. (c) 2005 Elsevier B.V. All rights reserved.