Construction of a Stable Crystalline Polyimide Porous Organic Framework for C2 H2 /C2 H4 and CO2 /N2 Separation.

Utilization of porous materials for gas capture and separation is a hot research topic. Removal of acetylene (C2 H2 ) from ethylene (C2 H4 ) is important in the oil refining and petrochemical industries, since C2 H2 impurities deactivate the catalysts and terminate the polymerization of C2 H4 . Carbon dioxide (CO2 ) emission from power plants contributes to global climate change and threatens the survival of life on this planet. Herein, 2D crystalline polyimide porous organic framework PAF-120, which was constructed by imidization of linear naphthalene-1,4,5,8-tetracarboxylic dianhydride and triangular 1,3,5-tris(4-aminophenyl)benzene, showed significant thermal and chemical stability. Low-pressure gas adsorption isotherms revealed that PAF-120 exhibits good selective adsorption of C2 H2 over C2 H4 and CO2 over N2 . At 298 K and 1 bar, its C2 H2 and CO2 selectivities were predicted to be 4.1 and 68.7, respectively. More importantly, PAF-120 exhibits the highest selectivity for C2 H2 /C2 H4 separation among porous organic frameworks. Thus PAF-120 could be a suitable candidate for selective separation of C2 H2 over C2 H4 and CO2 over N2 .