N-containing Porous Organic Polymers For CO₂, H₂S Adsorption And Conversio

The main component of natural gas is methane,but it also contains impurities such as CO₂ and H₂S gas.The presence of these impurities affects the quality of natural gas and also escapes into the atmosphere along with the use of natural gas,causing environmental problems such as the greenhouse effect or acid rain.However,the efficient and selective removal of CO₂ and H₂S gas from natural gas is still a challenging issue due to the differences in physicochemical properties between CO₂,H₂S and CH₄gas molecules.Commonly used low-temperature methanol,ammonia（amine）scrubbing and other natural gas purification processes have high operating costs,equipment corrosion,secondary pollution and other problems,especially the lack of resource utilization of captured CO₂ or H₂S highly selective capture pathway,the urgent need to develop efficient CO₂ and H₂S capture and conversion technology.While adsorption is considered as a cost-effective method,this paper revolves around the construction of porous organic polymers with CO₂ adsorption and conversion capabilities and selective separation of H₂S.A series of N-containing porous organic polymers were constructed by introducing different types of N-containing monomers and different kinds of linkers,focusing on the conformational relationship between adsorbent and CO₂ and H₂S adsorption and conversion capacity.The main research content of this paper is as follows:（1）CO₂ resource utilization,i.e.,the preparation of cyclic carbonate from CO₂ and epoxide is one of the green ways of CO₂ resource utilization.However,the preparation of catalysts with efficient catalytic ability of CO₂ is a challenging research topic.Therefore,an easily prepared Zn coordination polymer（ZnBr₂-CPs）with homogeneous catalytic properties and recoverable was synthesized for catalytic synthesis of cyclic carbonates from CO₂ and epoxide.The effects of temperature,pressure,catalyst amount and time on the catalytic reaction system were investigated using styrene oxide as a model substrate.Furthermore,the dual active sites in the structure of ZnBr₂-CPs synergistically catalyze the efficient conversion of CO₂.（2）Although ZnBr₂-CPs possess high efficiency in CO₂ catalytic conversion,the low specific surface area makes the CO₂ adsorption capacity of ZnBr₂-CPs low.Therefore,this subject introduces different N-containing monomers for Friedel-Crafts alkylation reactions and quaternization reaction with crosslinkers to obtain a series of N-containing porous organic polymers i.e.,hyper-crosslinked polymers（IHCPs）containing ionic sites.The high specific surface area of IHCPs makes them have good CO₂ adsorption capacity,and the interaction between CO₂ and IHCPs was investigated by thermodynamic and in situ-Fourier transform infrared spectroscopy.The Friedel-Crafts alkylation reaction between the N-containing monomer and the crosslinker is accompanied by quaternization of the N-containing monomer with benzyl groups to form ionic sites,which endows the IHCPs with the ability to catalyze the formation of cyclic carbonates from CO₂ and epoxides.The catalytic cycling experiments,Fourier transform infrared spectroscopy,and thermal filtration experiments further demonstrate that IHCPs not only have good CO₂ adsorption capacity,but also possess good structural stability during the catalytic reaction.（3）During the study of CO₂ adsorption and conversion of IHCPs,we found that IHCPs not only have good CO₂ adsorption ability but also have good H₂S adsorption ability.Based on this,a series of IHCPs were synthesized by the Friedel-Crafts alkylation and quaternization reactions of different N-containing monomers with crosslinkers in one step.The interaction between H₂S and IHCPs was investigated by thermodynamic and in situ-Fourier transform infrared spectroscopy,and in addition,IHCPs had a good H₂S/CH₄/N₂ selective adsorption capacity by IAST calculations.After six adsorption-desorption cycles,the H₂S adsorption capacity was still good and the chemical structure remained stable.