Synthesis and Characterization of Covalent Triazine Frameworks Based on 4,4'-(Phenazine-5,10-diyl)dibenzonitrile and Its Application in CO(2)/CH(4) Separation.

Covalent triazine frameworks (CTFs) have gained recognition as stable porous organic polymers, for example, for CO(2) separation. From the monomer 4,4'-(phenazine-5,10-diyl)dibenzonitrile (pBN), new pBN-CTFs were synthesized using the ionothermal method with a variation in temperature (400 and 550 °C) and the ZnCl(2)-to-monomer ratio (10 and 20). N(2) adsorption yielded BET surface areas up to 1460 m(2)g (-1). The pBN-CTFs are promising CO(2) adsorbents and are comparable to other benchmark CTFs such as CTF-1 with a CO(2) uptake of pBN-CTF-10-550 at 293 K of up to 54 cm(3) g(-1) or 96 mg g(-1), with a CO(2)/CH(4) IAST selectivity of 22 for a 50% mixture of CO(2)/CH(4). pBN-CTF-10-400 has a very high heat of adsorption of 79 kJ mol(-1) for CO(2) near zero coverage in comparison to other CTFs, and it also stays well above the liquefaction heat of CO(2) due to its high microporosity of 50% of the total pore volume.