High Gas Uptake and Selectivity in Hyper-Crosslinked Porous Polymers Knitted by Various Nitrogen-Containing Linkers.

By introducing various N-containing compounds as efficient linkers, a series of hyper-crosslinked porous polymers with high surface areas and gas-uptake values were synthesized by using the Friedel-Crafts alkylation reaction. Structural characterization indicated the presence of nitrogen atoms, and gas-sorption experiments revealed that the high gas uptake benefitted from the high surface areas and the incorporation of N-containing linkers as Lewis basic sites. Among these porous polymers, HCP-4 had the highest H2 uptake of 9.29 mmol g-1 at 77 K and 0.1 MPa and the highest C2 H2 uptake of 6.69 mmol g-1 at 273 K and 0.1 MPa, whereas HCP-3 showed the best CO2 uptake of 4.42 mmol g-1 at 273 K and 0.1 MPa. To understand better the important role played by nitrogen in these polymers, the isosteric heat of adsorption and adsorption selectivity of CO2 over N2 were calculated. The results showed that the triazine-based polymer HCP-1 had the highest CO2 over N2 selectivity of 75.4 at 295 K and 0.1 MPa, which makes it the most potential candidate for CO2 capture.