Hierarchical Porous and Zinc-Ion-Crosslinked PIM-1 Nanocomposite as a CO2 Cycloaddition Catalyst with High Efficiency

Graphical A metal-ion-crosslinked PIM-1 framework as heterogeneous catalyst is reported for promoting the CO 2 cycloaddition with epoxides. The new catalyst PIM-COONa-Zn demonstrates both high catalytic efficiency and good recyclability. CO 2 cycloaddition to epoxides is an effective and economical utilization method to alleviate the current excessive CO 2 emission situation. The development of catalysts with both high catalytic efficiency and high recyclability is necessary but challenging. In this context, a heterogeneous catalyst was synthesized based on a zinc-ion-crosslinked polymer with intrinsic microporosity (PIM-1). The high microporosity of PIM-1 promoted a high Zn 2+ loading rate. Additionally, the relatively stable ionic bond formed between Zn 2+ and the PIM-1 framework through electrostatic interaction ensured high loading stability. In the process of CO 2 cycloaddition with propylene epoxide, an optimized conversion of 90 % with a turnover frequency as high as 9533 h −1 could be achieved within 0.5 h at 100 °C and 2 MPa. After 15 cycles, the catalytic efficiency did not demonstrate a significant decline, and the catalyst was able to recover most of its activity after Zn 2+ reloading. This work thereby provides a strategically designed CO 2 conversion catalyst based on an ionic crosslinked polymer with intrinsic microporosity.