Efficient CO2 capture by triptycene-based microporous organic polymer with functionalized modification

• A series of TPPs were firstly achieved through one-step Friedel–Crafts reaction.
• The TPPs have been designed with surface functionalized porosities.
• The post-synthetic modification method was adopted to produce TPP-1-NH2.
• TPP-1-NH2 showed excellent CO2 adsorption capacity and high CO2/N2 selectivity.

Microporous organic polymers (MOPs) are an emerging class of materials constructed from organic molecular building blocks. However, to design MOPs with surface functionalized porosities and high CO2 adsorption capacity is still a critical challenge. In this work, starting from different chemical functionalized triptycene monomers, including amino (–NH2), formyl (–CHO), acetyl (–COCH3) and nitro (–NO2) functional groups, we achieved a series of three-dimensional rigid framework of pre-functionalized triptycene-based polymers (TPPs) through a simple one-step Friedel–Crafts reaction. Moreover, alkyl-substituted amino groups were further incorporated into the network by the post-synthetic modification of amine pre-functionalized polymer TPP-1. The resulted microporous organic polymer TPP-1-NH2 presented an excellent CO2 adsorption capacity (4.17 mmol g−1 at 273 K, 1 bar) and a high CO2/N2 selectivity (43.6 at 273 K), which was ascribed to the predominant micropores and high CO2 isosteric adsorption heat of 41 kJ mol−1. Therefore, it is believed that these MOPs with high physicochemical stability are promising candidates for selective CO2 capture by employing this functionalized modification method.

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