Design, Synthesis And Properties Of Bisazozolyl Organic Microporous Polymers

Energy and environmental issues are the main factors that limit the development of science and social in the long-term.Human consumes a lot of energy to maintain modern life style such as for manufacture,travel and food.In fact,almost everything we can do is inseparable from energy.Currently,the consumable energy mainly comes from fossil fuels such as oil,coal and natural gas,and the burning of these hydrocarbons is one of the main factors leading to the current environmental problems.The growing depletion of fossil fuels and environmental problems have led to research on new renewable energy and improved environmental practices.In this case,porous organic polymers fraturing with high surface area,excellent physicochemical stability,controllable structure and synthetic diversity,have attracted much attention because of their broad applications in areas such as gas adsorption,catalysis and energy storage.In general,porous organic polymers can be divided into six categories,manily including hyper-cross-linked polymers(HCPs),polymers of intrinsic microporosity(PIMs),porous aromatic frameworks(PAFs),covalent organic frameworks(COFs),Conjugated microporous polymers(CMPs),and covalent triazine frameworks(CTFs).Many studies have revealed that the design and selection of building block are critical to the porosity and performance of the resulting polymers.In this thesis,we selected N,N'-bicarbazole as the basic building unit based on a large number of literature review and data collection,and synthesized a series of porous organic polymers via various polymerization reactions using N,N'-bicarbazole derivatives with different functional groups,and structure-property relationship of these porous polymers was studied in detail.The main research contents and results are summarized below:(1)Two covalent triazine-based frameworks with high specific surface area were synthesized using trifluoromethanesulfonic acid(TFMSA)catalyzed trimerization reaction with tetra-cycano N,N'-bicarbazole derivatives.The resulting polymers showed high aurface area up to 868 m2g-1,and both polymer materials exhibited excellent carbon dioxide adsorption capacity and the gas selectivity.Cz-CTF1 showed a carbon dioxide adsorption capacity of 3.71 mmol g-1 at 273 K/1.13 bar,and the adsorption seclitivity of 100:1 for carbon dioxide to nitrogen.(2)The porous organic polymer of Cz-POP with porphyrin ring was synthesized by electrophilic substitution reaction from N,N'-bicarbazole derivative with formyl groups and pyrrole.This polymerization involves one-step reaction to form porphyrin ring,which is simple and inexpensive.Cz-POP showed high carbon dioxide adsorption capacity of 3.03 mmol g-1 at 273 K/1.13 bar,since the strong interaction between porphyrin ring and carbon dioxide molecule leads to the increased adsorption heat(31.3 kJ mol-1).(3)Two novel microporous two-dimensional(2D)bicarbazole-based covalent organic frameworks(Cz-COFs)with redox-active units and high degree of crystallinity were successfully synthesized via Schiff-base condensation reaction.Both Cz-COFs consist of layered lattices with periodic bicarbazole columns and tetragonal open micropores.The Cz-COFs show high Brunauer-Emmett-Teller specific surface area up to 2387 m2 g-1 and uniform micropore size,which allow for the high gas adsorption capacity of the Cz-COFs.In addition,the lithium ion batteries fabricated from the 2D Cz-COFs exhibited high charge capacity,excellent rate capability and long cycle life because of the high physicochemical stability,the high content of redox-active carbazole units,high surface area and uniform open nanopores in the Cz-COFs.(4)Porous carbon materials were prepared via different carbonation temperatures from the bicarbazole-based hyper-cross-linked porous organic polymer precursor.CzHCP-600 exhibited the highest surface area of 3478 m2 g-1 and carbon dioxide adsorption capacity of 5.54 mmol g-1,among the three porous carbon materials.In addition,the porous carbon materials showed excellent electrochemical properties for supercapacitors.The capacitance of CzHCP-700 based electode was found to be 362 F/g at a current density of 0.5 A/g.