Design And Preparation Of Alkaline Porous Ionic Materials And Its Catalytic Application Of CO₂ Cycloaddition Reactions

Ionic liquids?ILs?have attracted wide attention as a kind of typical green and environmentally friendly catalyst,owing to their unique properties such as less pollution,negligible vapor pressure,structure designability.Meanwhile,porous ionic materials derived from ILs take the advantages of porous materials,which can effectively overcome the shortcomings of many homogeneous catalysts in the chemical industry.In this thesis,the traditional base-catalyzed reactions such as cycloaddition of carbon dioxide with epoxides and Knoevenagel condensation reaction were selected to control the monomers structure,monomers content,temperature,time,catalyst dosage and polymerization solvent and used as to achieve the green and efficient catalytic process.The details are as follows:First,a series of different structures and basic ILs were synthesized and used for CO₂ cycloaddition reaction at atmospheric pressure.The results indicated that ILs with linear structure,strong basicity,active H,and small spatial structure were beneficial to the cyclization addition reaction.Compared with other homogeneous catalysts,the reaction conditions are milder,with excellent catalytic performance and efficient recycling performances.Through investigated the interaction of N-H⁺bonds in ILs with epoxides,a possible mechanism of cycloaddition catalysis was proposed.Secondly,in order to resolve the shortcomings of the homogeneous catalytic system?e.g.,difficult to recycle?.Based on the above research,we designed and synthesized a porous ionic monomer,having pore-rich structure,by a simple free radical copolymerization reaction.The mechanism of interaction between the catalyst and the substrates was explored by means of a serious of characterizations?XPS,BET,FTIR,SEM,TEM?.In addition,the effect of catalyst structure was further explored in cyclization addition.Results show that the porous ionic materials show good thermal stability,excellent recyclability,and efficient substrate universality.To the best of our acknowledge,it is the first time to convert CO₂ at low-pressure?0.15 bar?into cyclic carbonate with high yield??99%?without any metal or solvents additives.Moreover,the catalyst exhibited extremely efficient activity at room temperature and atmospheric pressure?25°C,1 bar?.Finally,based on the basicity of the porous ionic materials,it's further used in the Knoevenagel condensation reaction of benzaldehyde with ethyl cyanoacetate.After investigating the effects of conditions such as the ionic monomers content,monomers basicity,polymerization solvent,temperature,time and the amount of catalyst,it found that porous ionic material catalyst[PDVB-[AlTMG]Br-1 using EA as polymerization solvent shows higher catalytic performance in this catalytic process.In addition,the recyclability of the catalyst indicated that the porous ionic materials not only shows good thermal stability in the Knoevenagel condensation reaction but also display excellent thermal stability and recyclability in the cycloaddition reaction.