K‐doped CuO/ZnO with dual active centers of synergism for highly efficient dimethyl carbonate synthesis

Abstract

The application of heterogeneous catalysts in dimethyl carbonate (DMC) synthesis from methanol is hindered by low activation efficiency of methanol to methoxy intermediates (CH3O*), which is the key intermediate for DMC generation. Herein, a catalyst of alkali metal K anchored on the CuO/ZnO oxide is rationally designed for offering Lewis acid–base pairs as dual active centers to improve the activation efficiency of methanol. Characterizations of CO2‐TPD, NH3‐TPD, XPS, and DRIFTS revealed that the addition of Lewis base K observably boosted the dissociation of methanol and combined with Lewis acid CuO/ZnO oxide to adsorb the formed CH3O* stably, thus synergistically promoted the transesterification. Finally, the CuO/ZnO‐9%K2O catalyst exhibited the optimal catalytic activity, achieving a high yield of 74.4% with an excellent selectivity of 98.9% for DMC at a low temperature of 90°C. The strategy of constructing Lewis acid–base pairs provides a reference for the design of heterogeneous catalysts.

Characterization of alkaline earth metal-doped CeO2 nanocatalysts and their catalytic activities in the synthesis of dimethyl carbonate through a reaction between methanol and CO2

“…[4][5][6][7] The Chinese production capacity of dimethyl carbonate was 2339 kt a À1 in 2022 and the production capacity is predicted to be 5849 kt a À1 in 2026. 8 Dimethyl carbonate can be synthesized through several chemical reaction routes, such as reactions between methanol and phosgene, 9 methanol oxidative carbonylation on copper and zeolite-supported Co(II)-Schiff base complex catalysts, 6,10 transesterification of ethylene carbonate/propylene carbonate with methanol using methoxide and K-doped CuO/ZnO catalysts, 6,11,12 alcoholysis of urea with methanol, 8 and catalytic reactions of methanol with gaseous CO 2 catalyzed on Ce-based catalysts. 13 Although the processes of methanol oxidative carbonylation and transesterification of ethylene carbonate/propylene carbonate with methanol have been commercialized worldwide, 8 the synthesis of dimethyl carbonate through the catalytic reaction between methanol and gaseous CO 2 still attracts great attention from researchers because through this route, dimethyl carbonate and water could be dominantly produced with lower waste production, eqn (1).…”