Carbonate-based hyper-cross-linked polymers with pendant versatile electron-withdrawing functional groups for CO2 adsorption and separation

Abstract

The simple and highly efficient preparation of porous hyper-cross-linked polymers (HCPs) with high surface area and manifold functionalities for high-performance CO₂ uptake and selective separation has drawn significant attention in the past decade. Herein, three low-cost carbonates rich in electron-withdrawing carbonyl and ester groups, fluorine atoms and electron-donating heteroatoms such as N, were used as building blocks to fabricate a series of novel and functional HCPs via the typical one-step Friedel–Crafts alkylation reaction under mild conditions, which has been scarcely reported to date. The resulting functional polymers were permanently microporous and the polymer enriched with nitrogen atoms and carbonyl and ester groups possessed the highest BET surface area of 1367 m² g⁻¹, Langmuir surface area of up to 2058 m² g⁻¹, CO₂ uptake of 14.61 wt% at 273.15 K/1.00 bar, H₂ adsorption of 1.28 wt% at 77.3 K/1.00 bar, and CH₄ storage of 1.79 wt% at 273.15 K/1.00 bar. Besides, the structurally accessible functional groups and heteroatoms were able to endow the resultant polymers with improved gas adsorption selectivity for CO₂/N₂ (20.16) and CO₂/CH₄ (41.84) at 273.15 K and a low-pressure coverage of less than 0.3 bar according to Henry's law (initial slope ratio). In addition, it was found that by fine tuning the molecular structure of the employed building blocks, the texture property and gas capturing capacity of the obtained polymers can also be rationally tuned, and detailed insight from the viewpoint of structure–property relationships has been provided.