Direct Integration of Functionalized Bridges by One-Step Superacid-Catalyzed Reaction to Fabricate Porous Polymers for CO2 Capture and Separation

A novel class of ultra-microporous functionalized porous organic polymers (POPs) was developed starting from glyoxylic acid as a cross-linker and triflic acid as a catalyst on polyaromatic monomers, generating in situ methine bridges with carboxylic acids. This one-pot synthetic method generated functionalized POPs with high connectivity per each aromatic group and a high density of aliphatic carboxylic acids decorating the pore walls. Remarkably, the functional groups were transformed into esters, Na- and Li-carboxylates by post-synthetic modification with high yields, generating polyionic porous polymers. These porous polymers displayed excellent CO2 adsorption at 298 K and isosteric heat of adsorption with values as high as 50 kJ mol-1 for the Na-containing POP endowed with numerous ionic charges, as estimated by direct measurements with microcalorimetry coupled to CO2 adsorption isotherms. Dynamic breakthrough experiments on self-supporting monolithic composites demonstrated high selectivity for CO2 adsorption over N2 up to 500 for diluted streams and 340 under relevant conditions for carbon capture from flue gases (0.15 CO2 partial pressure).