One-step multiple-site integration strategy for CO2 capture and conversion into cyclic carbonates under atmospheric and cocatalyst/metal/solvent-free conditions

Abstract

The capture of CO2 and subsequent conversion into high value-added chemicals under atmospheric conditions is an on-going challenge. This work reports a facile multiple-site integration strategy for the capture of low-concentration CO2 and subsequent cocatalyst/metal/solvent-free coupling with epoxides to synthesize cyclic carbonates under atmospheric conditions. Through the one-step integration of commonly-used imidazolium ionic liquids (ILs) and quaternary ammonium salt, porous polyILs with acidic/basic moieties (–NH2, –COOH), active cations (imidazolium, quaternary ammonium) and nucleophilic counterions (Br–, Cl–, OH–) have been fabricated. The cooperation of nucleophilicity, basicity and acidity, which is critical for the activation of CO2 and epoxides, has been flexibly modulated via regulating the type and content of the multiple-sites. The polyILs show good low-concentration CO2 affinity, high catalytic activity under atmospheric conditions, efficient recyclability and excellent tolerance for a variety of epoxides, and the new strategy developed shows great potential for practical applications in low-energy fixation of CO2.