Regulating basicity of porous poly(ionic liquid)s for CO2 fixation into dimethyl carbonate under mild condition

Abstract

Direct carbon dioxide (CO₂) conversion into valuable chemicals like dimethyl carbonate (DMC) is an atom efficient avenue for CO₂ utilization but greatly challenges the catalyst designation because the requirement of multiple active sites. Herein, regulation of the basicity of porous poly(ionic liquid)s (PPILs) was reached by post-treating epoxy-functional precursor and utilizing 1,5,7-triazodicyclic [4.4.0] Dec-5-ene (TBD) to convert epoxy functional ionic moieties into the multifunctional sites with nucleophilic-leaving capable anions, hydroxyl group and TBD derived basic sites. The constructed catalyst was highly active in the one-pot and two-step DMC synthesis by coupling the CO₂ cycloaddition with epoxide and successive transesterification. A high yield up to 93% was observed by using atmospheric CO₂ under the metal-solvent-additive free condition. Stable reusability and extendibility by using multiple epoxides further reveal the efficiency and potentiality of the present catalyst in CO₂ fixation.