Fine-Tuning Electron–Donor Capability in the Basic Anion of Poly(ionic liquid) Frameworks for Revolutionizing Catalytic Synthesis of Ethyl Methyl Carbonate with Both Ultrahigh Catalytic Activity and Selectivity

Abstract

Ethyl methyl carbonate (EMC) is a crucial solvent extensively utilized in lithium-ion battery electrolytes; the transesterification of dimethyl carbonate (DMC) with ethanol is a pivotal reaction for EMC production. However, this reaction faces challenges due to the trade-off between catalytic activity and selectivity from the basic catalysts. In this issue, we report an innovative strategy through fine-tuning the electron-donor capability of the basic phenolate anion ([PhO]) in a novel poly(ionic liquid) (PIL) framework, as synthesized via an alkylation reaction between 1,3,5-tris(bromomethyl)benzene, biphenyldiimidazole, and N,N′-carbonyldiimidazole (CDI) to trigger targeted basicity that can directionally catalyze the transesterification of DMC with ethanol, so as to achieve both ultrahigh catalytic activity and selectivity toward EMC. By varying the substituent groups with electron-withdrawing and electron-donating effects on the phenolate anion, the PILs show expected changes in the catalytic performance, following well with the trend of charge density on these substituted phenolate anions. The optimized catalyst [CPIL-CDI][MeOPhO], induced by p-methoxyphenolate anions, allows an extraordinary EMC yield of 72.19% and an EMC selectivity of 91.48% under mild conditions without any process intensifications, suppressing all of the reported catalysts reported to date. Outcomes and approaches shown in this work have the potential to expedite the systematic design of cations and anions within PILs for industrial-scale EMC production through environmentally friendly transesterification processes.

Intensification Mechanism of Acidic Imidazole-Based Ionic Liquids on the Synthesis of 1,3,5-Trioxane Catalyzed by Sulfuric Acid

“…The addition of [EMIm]­HSO 4 intensified the reaction of TOX synthesis from FA solution was also found . The acidity and polarity of acidic ILs are also different due to the different number of sulfonic acid groups. , They showed good catalytic performance in different reactions. − They may show different effects on the reaction of TOX synthesis from FA solution for their different properties. Therefore, the effects of introduced acidic ILs on the liquid reaction of TOX synthesis from FA solution are needed to be studied systematically, and the intensification mechanism of ILs on the reaction itself is also needed to be clarified.…”