Modulating pore microenvironment in a robust ionic porous polymer for efficient propyne/propylene separation

Developing highly selective and stable adsorbents for capturing trace propyne from propylene to produce polymer-grade propylene is of great significance but challenging. Porous organic polymers with high stability are promising for propyne removal, but display trade-off effect between capacity and selectivity. Here, we report a novel ionic porous polymer with stable structure and well-tuned pore microenvironment featured abundant microporosity and inorganic anions, which realized efficient propyne/propylene separation. Gas adsorption experiments demonstrate excellent propyne/propylene selectivity (43) and boosted diffusion performance. Meanwhile, polymer-grade propylene (≥99.5 %) could be obtained with the highest productivity (5.7 mol kg−1) among porous organic polymers. Molecular simulations reveal the high-density anions in P(Ph4Im-Br-DVB) enable effective discrimination of propyne from propylene with hydrogen-bonding like interactions. This work highlights how pore microenvironment tuning in porous organic polymers can realize the efficient gas separation.