A comparative gas sorption study of dicarbazole-derived microporous hyper-crosslinked polymers

Tailoring selective gas uptake properties of porous organic polymers is very crucial for their future use in gas separation and storage, however, unraveling the impact of polymerization methods and linkers while fixing the core of the polymers remains a great challenge. Here, a comparative study of three microporous networks synthesized by linking dicarbazole (4,4 '-di(9H-carbazol-9-yl)-1,1 '-biphenyl, YBN) building blocks with dimetoxymethane, dimetoxybenzene, and cyanuric chloride. Linkers for giving hypercosslinked, hypercosslinkedcovalent and covalent triazine frameworks through FeCl3 and AlCl3 catalyzed Friedel-Crafts reactions have been presented. The resulting microporous polymers, namely YBN-DMM, YBN-DMB, and YBN-CC were fully characterized by spectral and analytical methods then comparatively tested for gas uptake (CO2, CH4, O-2, CO, and H-2) and selectivity (CO2/N-2, CO2/O-2, for CO2/CO and CO2/CH4) under ambient pressure and three different temperature. These obtained polymers exhibit high BET specific surface area up to 968 m(2) and predominantly ultramicroporous character, and remarkable thermal (up to 350 degrees C) and chemical stability in various solvents including concentrated hydrochloric acid. According to the linker, polymers have high gas uptake properties reaching 12.66 wt % CO2, 1.64 wt%. CH4, 1.04 wt% CO adsorption at 1 bar/273 K and 1.59 wt % H-2 adsorption at 1 bar/77 K with interesting N-2-phobia down to 0.04 wt% with relatively O-2 phobia down to 0.22 wt% at 1 bar/ 320 K respectively. According to IAST calculations, it was observed that the selectivity properties, especially required for post-combustion processes at high pressures and temperatures, increase unusually by changing the linkers reaching up to 159 for CO2/N-2, 63.5 for CO2/O-2, 63.76 for CO2/CO, 7.47 for CO2/CH4.

Automated summary

Tailoring selective gas uptake properties of porous organic polymers is crucial for gas separation and storage. In this study, three microporous networks with different linkers were synthesized and characterized, showing that the gas uptake properties and selectivity of the polymers can be controlled by the choice of linker. The obtained polymers exhibit high BET specific surface area, ultramicroporous character, thermal and chemical stability, and high gas uptake properties and selectivity.