Processing nanoporous organic polymers in liquid amines

Covalent Amine Tethering on Ketone Modified Porous Organic Polymers for Enhanced CO2 Capture

Effective removal of excess greenhouse gas CO₂ necessitates new adsorbents that can overcome the shortcomings of the current capture methods. To achieve that, porous materials are often modified post-synthetically with reactive amine functionalities but suffer from significant surface area losses. Herein, we report a successful amine post-functionalization of a highly porous covalent organic polymer, COP-130, without losing much porosity. By varying the amine substituents, we recorded a remarkable increase in CO₂ uptake and selectivity. Ketone functionality, a rarely accessible functional group for porous polymers, was inserted prior to amination and led to covalent tethering of amines. Interestingly, aminated polymers demonstrated relatively low heats of adsorption, which is useful for the rapid recyclability of materials, due to the formation of suspected intramolecular hydrogen bonding.

Quantifying the nitrogen effect on CO2 capture using isoporous network polymers

The impact of nitrogen atoms on CO₂ binding was evaluated for two isostructural porous bisimidazole-linked polymers (BILPs), which serendipitously had identical surface areas and pore size distributions, a very rare observation. The two structures differ only in the core of the trialdehyde component, the nitrogen atom (BILP-19) versus benzene ring (BILP-5). Such a slight difference, however, has brought about a stronger CO₂ capture capacity of BILP-19 and hence increased CO₂/N₂ separation capability.