Hydroxyl-Based Hyper-Cross-Linked Microporous Polymers and Their Excellent Performance for CO₂ Capture

Abstract

A series of benzyl alcohol (BA)-based hyper-cross-linked microporous polymers (HCPs) were designed and synthesized via facile Friedel–Crafts alkylation using formaldehyde dimethyl acetal (FDA) as external cross-linker promoted by anhydrous ferric chloride (FeCl3). Results demonstrated that Brunauer–Emmett–Teller (BET) specific surface area and pore volume for the HCPs could be controlled by adjusting the amount of FDA and FeCl3. The HCPs obtained under optimal conditions showed a BET specific surface area up to 1101 m2/g, whose capacity of CO2 uptake could be as high as 3.03 mmol/g at 273 K/1.0 bar. The isosteric heats of CO2 sorption for the BA-based HCPs exceed 27 kJ/mol at the low coverage. In addition, the polymer networks possessed high CO2/N2 selectivity of 42. Compared with those BA-based HCPs which is without FDA, the prepared material has higher BET specific surface area and superior CO2 adsorption properties. These results demonstrated that these prepared HCPs are promising for CO2 capture and sequestration.