Porphyrin-based porous polyimides: Synthesis, porous structure, carbon dioxide adsorption

A novel dianhydride 3,3'-bis(3,4-dicarboxyphenoxy)-4,4'-diphenylethynyl biphenyl dianhydride (BPEBPDA) and a new tetramine monomer 5,10,15,20- tetra[4-[(3-aminophenyl) ethynyl] phenyl] porphyrin (TAPEPP) were successfully synthesized. Porphyrin-based polyimides (PPBPIs) were synthesized from BPEBPDA and porphyrin-based building blocks (TAPP and TAPEPP) via polymerization reactions. The porphyrin-based porous polyimide networks (PPBPI-CRs) were obtained from PPBPIs through thermal crosslinking reactions. The PPBPI-CRs exhibited BET surface areas (682 m(2) g(-1) and 693 m(2) g(-1)) and CO2 uptakes (2.0 mmol g(-1) and 1.67 mmol g(-1) at 273 K and 1 bar) as well as the separation factors of CO2/N-2 (37.63, 28.97) and CO2/CH4 (7.51, 5.61). Meanwhile, PPBPI-CRs showed an enhanced CO2 isosteric enthalpies of adsorption (25.1 kJ mol(-1) and 30.1 kJ mol(-1)) than other porous polymers.