Synthesis and characterization of crosslinked porphyrin-based polyimides from different terminal alkynyl groups for carbon dioxide adsorption and separation

摘要

We fabricated three crosslinked porphyrin-based polyimides (PPBPI-CRs) from PEPHQDA, TAPP and three terminal anhydrides (PA, PEPA and PENA) via alkynyl groups crosslinking reactions. PPBPI-CRs had permanent porosities and revealed outstanding thermal stabilities. Affected by u-stacking and molecular sizes effect, with increasing conjugate and molecular sizes effect in different terminal anhydrides, porphyrin-based polyimides (PPBPIs) revealed decreased specific surface areas (106.8-8.3 m(2 )g(-1)), whereas, PPBPI-CRs showed increased BET surface areas (1.8-633 m(2) g(-1)). Meanwhile, PPBPI-CRs had considerable CO2 uptakes (1.37, 2.01 and 2.37 nunol g(-1)) and isosteric heats of CO2 adsorption (34.8, 27.5 and 22.6 kJ mol(-1)). The PPBPI-CRs had CO2/N-2 (39.83, 36.95, 40.08) and CO2/CH4 (14.13, 9.78, 10.87) separation selectivities.