Synthesis And Porosity Engineering Of Triazine-based Nanoporous Organic Polycarbazole (NOPs)

:Nanoporous organic polymers are constructed via strong covalent bonds between the organic linkers. Currently, NOPs are a fascinating class of nanoporous materials with high surface area and poristy, lightweight skeleton construction, controllable physical-chemical property, permanent pore structure, abundant construction and modification methods. These materials have attracted ever-increasing attention from different field scientists, owing to their potential application in gas storage, heterogeneous catalysis, adsorption separation and heavy metal ions adsorption. In this work, four carbazole-modified polytriazine networks were synthesized by utilizing the optimized dynamic trimerization reaction in ZnCl2ionothermal conditions. Series of characterization methods were used to study gas storage and adsorption separation of the polymers.Firstly, the commercially available carbazole was choosen as the starting unit, the aromatic nitrile was obtained throughout a series of reactions. A consolidated ionothermal strategy was developed for the polymerization of thermally unstable carbazole-based nitriles to construct nanoporous organic polymer (NOP-18). The chemical structures were confirmed by FTIR, XRD, SEM, TEM, et al. The low pressure nitrogen adsorption desorption isotherm shows that the material BET surface area up to1187m2/g. NOP-18possesses a considerable CO2uptake (133mg/g,273K,1bar) and isoteric heats value (Qst,34kJ/mol) and displays CO2/N2ideal selectivity of45(273K).Secondly, the porosity was controlled as well as the pre-functionalization of pore walls of a carbazole-modified polytriazine framework by the introduction of three different appended functional groups (methyl, ethyl acetate and phenyl). All the synthesized nanoporous organic polytriazines (NOPs) display good thermal stability, high BET surface areas and microporosities. The phenyl-anchored framework (NOP-21) exhibits the highest CO2capacity (12.3wt%at 273K/1bar) and isoteric heats value (Qst,37kJ/mol). Besides, the highest selectivity based on ideal adsorbed solution theory (IAST) model at273K was amazingly observed for the ethyl acetate-appended framework (NOP-20):CO2/N281(273K,1.0bar), because of uniform ultramicropores through pore engineering. These results suggest a good feasibility for constructing high performance organic porous CO2sorbents by controlling porosity.