Extensive Screening of Solvent-Linked Porous Polymers through Friedel-Crafts Reaction for Gas Adsorption

Scalability, cost and feasibility of porous structures in gas capture are prerequisites for emerging materials to be promising in industry. Here, we present a simpler variant of Friedel-Crafts synthesis of highly porous covalent organic polymers (COPs) based on an unprecedented solvent mediated cross-linking. Alkyl chlorides behave as both solvents and linkers in the presence of AlCl3. Studies on three classes of 18 different monomers using dichloromethane, chloroform, and 1,2-dichloroethane lead to produce 29 new COPs (124-152). Polymers were characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, elemental composition analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and porosity analyzer. The synthesized COPs exhibited structures from nonporous to highly porous morphologies with Brunauer–Emmett–Teller (BET) surface areas as high as 1685 m2 g-1. These COPs showed high gas uptake towards CO2 (up to 4.71 mmol g-1 at 273 K, 1.1 bar), CH4 (up to 1.31 mmol g-1 at 273 K, 1.1 bar), and H2 (up to 2.02 wt.% at 77 K, 1.1 bar). The findings point to significant potential in producing sustainable porous materials through simple and scalable methodology developed here.