Mesoporous poly(ionic liquid)s with dual active sites for highly efficient CO2 conversion

Abstract

Atmospheric CO2 concentrations are soaring due to the continued use of fossil fuels in energy production, an anthropogenic activity that is playing a leading role in global warming. Thus, research aimed at the capture and conversion of CO2 into value-added products, such as cyclic carbonates, is booming. While CO2 is an abundant, cheap, non-toxic, and readily accessible C1 feedstock, its thermodynamic stability necessitates the development of highly efficient catalysts that are able to promote chemical reactions under mild conditions. In this work, a novel mesoporous poly(ionic liquid) with dual active sites was synthesized through a facile method that involves co-polymerization, post-synthetic metalation, and supercritical CO2 drying. Due to a high density of nucleophilic and electrophilic sites, the as-prepared poly(ionic liquid), denoted as P2D-4BrBQA-Zn, offers excellent performance in a CO2 cycloaddition reaction using epichlorohydrin as the substrate (98.9% conversion and 96.9% selectivity). Moreover the reaction is carried out under mild, solvent-free, and additive-free conditions. Notably, P2D-4BrBQA-Zn also efficiently promotes the conversion of various other epoxide substrates into cyclic carbonates. Overall, the catalyst is found to have excellent substrate compatibility, stability, and recyclability.

Keywords

• Mesoporous poly(ionic liquid)
• Nucleophile/electrophilic sites
• Carbon dioxide cycloaddition
• Heterogeneous catalysis
• Supercritical CO2 drying