One-pot synthesis of pyridine-based ionic hyper-cross-linked polymers with hierarchical pores for efficient CO₂ capture and catalytic conversion

A kind of pyridine-based ionic hyper-cross-linked polymers (Py-HCP-X, X = Cl, Br) with high surface area, plentiful hierarchical pores and abundant catalytic active units were prepared via a one-pot method. Adsorption measurements showed that the as-prepared Py-HCP-X exhibited high CO₂ capture capacity (up to 1.72 mmol g⁻¹, 273 K and 1 bar). Importantly, Py-HCP-Br displayed excellent catalytic activity for the cycloaddition of CO₂ to epoxides under metal/cocatalyst/solvent-free conditions. And the propylene carbonate was produced in 97% yield with an excellent selectivity of 99% at 120 °C and 2.0 MPa CO₂ for 8 h. The high performance of the present catalyst is ascribable to synergistic contributions of plentiful hierarchical pores and abundant nucleophilic bromide ions and pyridine-based active units in the Py-HCP-Br catalyst. Additionally, the catalyst is able to be simply separated by centrifugation and reused for four runs without significant loss in the performance, furthermore, the catalyst exhibits great structural stability and substrate universality.