The role of interactions between the cationic backbone and basic anions in green and ultra-selective catalytic synthesis of ethyl methyl carbonate in tunable ionized frameworks

Abstract

The significance of renewable energy sources underscores the importance of developing efficient battery technologies. Ethyl methyl carbonate (EMC), with its superior performance as an electrolyte, is widely utilized in lithium-ion batteries. However, the production of EMC through green transesterification of dimethyl carbonate (DMC) with ethanol encounters challenges due to low EMC selectivity and catalyst reusability issues. In this study, we present the initial instance of utilizing an imidazole-based ionic framework, [CPIL-M]_n[PhO], which exhibits an interaction between its cationic backbone and basic anions. This interaction is specifically designed to catalyse the selective transformation of basic anions with suitable Lewis basicity in the production of EMC via transesterification. The introduction of N,N′-carbonyldiimidazole into the ionic framework allows for tunable modulation of Lewis basicity on an electronic level, enhancing catalytic activity without compromising selectivity. These innovative designs enable [CPIL-M]₄[PhO] to exhibit remarkable performance, achieving 69.02% EMC yield and 90.19% selectivity, outperforming most reported catalysts. These findings could pave the way for the accelerated development of efficient catalysts for the sustainable production of EMC through transesterification methods in the future, thereby supporting the energy-efficient transition towards renewable energy sources.