Synthesis of dimethyl carbonate from propylene carbonate and methanol using CaO–ZrO 2 solid solutions as highly stable catalysts

Abstract

CaO–ZrO 2 catalysts were prepared by coprecipitation and their catalytic performances were evaluated in the synthesis of dimethyl carbonate from propylene carbonate and methanol. The characterization by XRD, N 2 adsorption, XPS and CO 2–TPD indicated that Ca 2+ ion substituted for Zr 4+ ions in the host lattice to form homogeneous CaO–ZrO 2 solid solution when Ca/(Ca + Zr) ratio changed from 0.1 to 0.3, and CaO segregated at grain boundaries with Ca/(Ca + Zr) ratio from 0.4 to 0.5. As a result, the catalysts showed different activity and stability towards the transesterification of propylene carbonate and methanol into dimethyl carbonate. The activity of catalysts was improved with increase in Ca content, whereas high stability was shown with Ca/(Ca + Zr) ratio below 0.3. The formation of homogeneous CaO–ZrO 2 solid solution was responsible for the stability of catalysts.