Aromatic Amine-Functionalized Covalent Organic Frameworks (COFs) for CO 2 /N 2 Separation.

CO 2 is a prominent example for an exhaust gas, and it is known for its high impact on global warming. Therefore, carbon capture from CO 2 emissions of industrial processes is increasingly important to halt and prevent the disruptive consequences of global warming. Covalent organic frameworks (COFs) as porous nanomaterials have been shown to selectively adsorb CO 2 in high quantities and with high CO 2 /N 2 selectivity. Interactions with amines are recognized to selectively adsorb CO 2 and help capture it from exhaust emissions. Herein, a novel COF (Me 3 TFB-(NH 2 ) 2 BD), which was not accessible via a direct condensation reaction, was synthetized by dynamic linker exchange starting with Me 3 TFB-BD. Despite the linker exchange, the porosity of the COF was largely maintained, resulting in a high BET surface area of 1624 ± 89 m 2 /g. The CO 2 and N 2 adsorption isotherms at 273 and 295 K were studied to determine the performance in carbon capture at flue gas conditions. Me 3 TFB-(NH 2 ) 2 BD adsorbs 1.12 ± 0.26 and 0.72 ± 0.07 mmol/g of CO 2 at 1 bar and 273 and 295 K, respectively. The COF shows a high CO 2 /N 2 IAST selectivity under flue gas conditions (273 K:83 ± 11, 295 K: 47 ± 11). The interaction of the aromatic amine groups with CO 2 is based on physisorption, which is expected to make the regeneration of the material energy efficient.