Design,synthesis And Properties Of Ionic Heteroatom Porous Organic Polymers

The development of society cannot be achieved without energy,and fossil fuels are still the main means of energy supply in today’s society.However,the excessive use of fossil fuels has resulted in excessive emissions of carbon dioxide,which has led to a series of serious environmental problems such as global warming,ocean acidification and sea level rise.In addition,the reckless discharge of organic pollutants has caused serious water pollution problems,which seriously threaten the health and safety of the earth’s organisms.The decline of air and water quality has seriously affected human production and life,and effective treatment of environmental problems caused by carbon dioxide and organic dyes has become a focus of society.Converting carbon dioxide into high value-added chemicals is the most economical and feasible way to reduce greenhouse gas emissions and slow down global warming on a large scale in the future;Photocatalytic technology is an efficient,green and safe treatment method for removing organic pollutants from water.Catalyst materials are an important part of the catalytic conversion of CO2 and photocatalytic degradation of organic pollutants.Porous organic polymers(POPs)are porous materials composed of light elements(C,H,O,N,etc.)linked by covalent bonds.There are broad application potential and prospects in the field of heterogeneous catalysis because of POPs’ special advantages,such as adjustable pore properties,rich synthesis methods,diverse modification methods,and excellent acid-base stability.In this thesis,we design and synthesized a variety of heteroatom porous organic polymers with cationic frameworks,and investigated in detail their catalytic performance in CO2 cycloaddition reactions and degradation of organic pollutants under visible light.The main research results of this thesis are as follows:1.The Sonogashira-Hagihara coupling reaction between viologen-based dibromine and triethynylbenzene was utilized to construct viologen-based porous organic polymers(VPOPs)with cationic backbones.Subsequently,the polymer HVPOPs with hollow structure were constructed by the hard template method,and the anions in the polymer were exchanged by operation of ion exchange to obtain a series of HVPOP-X(X = Cl,Br,I)with different anions.We have tested the catalytic performance of(H)VPOPs for CO2 cycloaddition reaction,and after a series of comparative experiments,HVPOP-Br with hollow structure can achieve efficient conversion of CO2 to cyclic carbonate under non-cocatalyst,solvent-free and metalfree conditions,and has good substrate universality and catalytic cycle stability.This work confirms that the enhancement of the catalytic properties of POPs can be achieved by simply modifying the microscopic morphology and can reduce the introduction of expensive monomers and the intervention of metals.2.The ionic heteroatomic porous organic polymer VTz Tz T bridged by thiazolo[5,4-d]thiazole(Tz Tz)with both Tz Tz,pyridinium and triazine ring structures was designed and synthesized,which exhibited good catalytic performance in CO2 cycloaddition reactions and photocatalytic dye degradation.A low catalytic amount of VTz Tz T(0.4 mol%)can completely convert 20 mmol epichlorohydrin to cyclic carbonate within 6 h at 5 bar CO2 and 100 °C.In addition,VTz Tz T with cationic backbone can selectively adsorb anionic dyes in water and degrade them efficiently under visible light.The above results indicate that VTz Tz T is a bifunctional porous organopolymer catalyst with powerful catalytic performance,which provides a reference for the development of new multifunctional porous organocatalytic materials.