N-doped porous polymer with protonated ionic liquid sites for efficient conversion of CO2 to cyclic carbonates

A N-doped porous polymer with protonated ionic liquid sites was fabricated by a solvent-free self-assembly synthesis of resorcinol/formaldehyde resin, followed by modification with hydrobromic acid (HBr) to introduce ionic sites. Compared with the parent polymer PIP-HP, polymer PIP-HP-HBr maintains a high specific surface area after ion site construction, and the elevated activity was also acquired under metal/solvent/cocatalyst-free conditions with up to 99% yield of cyclic carbonates. Furthermore, the PIP-HP-HBr as a heterogeneous catalyst can be readily recovered and demonstrate excellent cycling stability. In addition, a plausible catalytic mechanism had been proposed that the high catalytic activity originates from the synergistic effect of hydrogen bond donor -OH and nucleophilic anion Br-.