Synergistic Catalysis on Adjustable Acid−Base Active Sites: Efficient Synthesis of Dimethyl Carbonate by Transesterification

Abstract

The green chemical dimethyl carbonate has become indispensable in multiple industries and is commonly produced by transesterification. Heterogeneous catalysts have received considerable research attention owing to their recyclability and environmental benefits. This work reports a series of Na-doped C3N4 catalysts with adjustable acid−base sites. The synergistic effect between acid−base sites significantly enhances methanol adsorption and dissociation, thereby promoting dimethyl carbonate formation. Theoretical calculations reveal charge redistribution in 0.15Na-CN, and the calculated adsorption energy and bond dissociation energy confirm that the synergistic effect accounts for enhanced methanol activation. In situ characterization confirms the adsorption and activation of reactants on the catalyst surfaces. The 0.15Na-CN catalyst achieves a dimethyl carbonate yield of 89.94% and a selectivity of 99.56% at 80 °C after 4 h of reaction, with a turnover frequency of 37.37 h−1. Moreover, 0.15Na-CN demonstrates excellent catalytic stability. This work provides an approach for the synergistic catalytic synthesis of dimethyl carbonate.