Hypercrosslinked microporous polymers based on carbazole for gas storage and separation

Abstract

Two hypercrosslinked microporous organic polymer networks from carbazole derivatives have been synthesized via Friedel–Crafts alkylation using a formaldehyde dimethyl acetal crosslinker promoted by anhydrous FeCl₃. Both of the polymer networks are stable in various solvents and thermally stable. The polymer network FCTCz produced from a dendritic carbazole building block shows much higher Brunauer–Emmet–Teller specific surface area of 1845 m² g⁻¹ than the dicarbazolic polymer network of FCBCz (1067 m² g⁻¹). FCTCz exhibits a high carbon dioxide uptake ability of 4.63 mmol g⁻¹ at 1.13 bar and 273 K with a hydrogen uptake ability of 1.94 wt% (1.13 bar/77 K). In addition, both of the polymer networks exhibit good ideal CO₂/N₂ selectivity (26–29) and CO₂/CH₄ selectivity (5.2–5.8) at 273 K. These results demonstrated that this kind of polymer network is a very promising candidate for potential applications in post-combustion carbon dioxide capture and sequestration technology.