Regulating the Lipophilicity of an Acid–Base Bifunctional Catalyst to Enhance the Performance of Catalytic Synthesis of Ethyl Methyl Carbonate

Ethyl methyl carbonate (EMC) is the most extensively used solvent in lithium-ion battery electrolytes. In recent years, the technology for producing EMC through the highly atom-economical transesterification of dimethyl carbonate and diethyl carbonate has garnered widespread attention. However, the commonly used sodium alkoxide basic catalysts exhibit poor catalytic activity due to their insolubility in this nonpolar reaction system. To address this, basic ionic liquids were confined and supported on a lipophilic carrier (UiO-66-NDC) by controlling the lipophilicity, ionic liquid loading, and pore structure through substituent groups on UiO-66-NDC. This led to the development of a catalyst with superior catalytic performance, [DBU⁺][IM^-]@UiO-66-NDC(50). At 108.7 °C, a catalyst dosage of 9.7 wt %, and a 1.4:1 DMC:DEC ratio for 4 h, the yield of EMC reached 62.5%, achieving high catalytic activity for the transesterification synthesis of EMC. Furthermore, the study explored the lipophilicity variations during the modification of [DBU⁺][IM^-]@UiO-66-NDC(<i>X</i>) with naphthyl groups, revealing the mechanism behind the formation of lipophilicity. Finally, using the prepared [DBU⁺][IM^-]@UiO-66-NDC(50) catalytic material, the reaction kinetics for the transesterification synthesis of EMC from dimethyl carbonate and diethyl carbonate was investigated, providing support for the development of lithium-ion battery energy storage technology.