Construction of a Stable Crystalline Polyimide Porous Organic Framework for C2H2/C2H4 and CO2/N2 Separation

Utilization of porous materials for gas capture and separation is a hot research topic. Removal of acetylene (C2H2) from ethylene (C2H4) is important in the oil refining and petrochemical industries, since C2H2 impurities deactivate the catalysts and terminate the polymerization of C2H4. 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 C2H2 over C2H4 and CO2 over N-2. At 298 K and 1 bar, its C2H2 and CO2 selectivities were predicted to be 4.1 and 68.7, respectively. More importantly, PAF-120 exhibits the highest selectivity for C2H2/C2H4 separation among porous organic frameworks. Thus PAF-120 could be a suitable candidate for selective separation of C2H2 over C2H4 and CO2 over N-2.