CaO-ZrO₂ catalysts with CaO content ranging from 10% to 50% were prepared by coprecipita-tion and their catalytic performances were evaluated in the synthesis of dimethyl carbonate from propylene carbonate and methanol. The characterization by XRD, FT-IR, BET, ICP, XPS and CO₂-TPD indicated that when CaO content was higher than 30%, CaO segregated at grain boundaries and the catalysts showed high activity but low stability. Whereas, Ca^2＋ ion substituted for Zr^4＋ ions in the host lattice to form homogeneous CaO-ZrO₂ solid solution when CaO content changed from 10% to 30%, as a result, the base strength were enhanced and the catalysts showed both high activity and stability towards the synthesis of dimethyl carbonate. The formation of homogeneous CaO-ZrO₂ solid solution was responsible for the stability of catalysts.

Key words: solid base, stability, solid solution, dimethyl carbonate