Triptycene based microporous polymers (TMPs): Efficient small gas (H-2 and CO2) storage and high CO2/N-2 selectivity

摘要

In contemporary research, there is a growing interest in the development of novel porous materials that can be used as adsorbents for small gas molecules such as CO2 and H-2. This is important from a perspective of more efficient energy alternative and a cleaner environment. Hyper-cross-linked polymers are a subclass of microporous organic polymers that are also reportedly known to efficiently adsorb H-2 and CO2. In this context, triptycene based microporous polymers are known to exhibit high gas storage and separation properties. Herein, facile synthesis of a set of three triptycene based microporous polymers (TMPs) is described. TMPs were prepared by crosslinking triptycene monomers with various (bromomethyl)benzene units using AlCl3 catalyzed Friedel-Crafts alkylation reactions in high yield. Gas uptake experiments indicate that TMPs are microporous having moderately high surface areas (up to 1372 m(2) g(-1)). Interestingly, TMP3 demonstrated very high reversible adsorption of molecular H-2 (221% by mass at 1 bar/77 K) and it may be considered in the league of porous organic frameworks demonstrating outstanding H-2 uptake at low pressure. Simultaneously, these polymers also show quite high CO2 uptake at 273 K and 1 bar (up to 223 mg g(-1)). Additionally TMPs have also exhibited very high CO2/N-2 gas selectivity (up to 70). Considering the facile synthetic protocol of TMPs (mandatory for scale-up synthesis), large H-2 and CO2 uptake and concurrent high CO2/N-2 (up to 70) selectivity, these are potential materials for clean energy applications. (C) 2017 Elsevier Inc. All rights reserved.