Design And Synthesis Of Lewis Acidic Ionic Liquid And Its Application In Friedel-Crafts Reactions

4,4’-Dichlorodiphenyl sulfone is the main raw material for manufacturing engineering plastics such as polysulfone and polyethersulfone,as well as an important intermediate for pharmaceuticals,dyestuffs and pesticides.At present,the domestic 4,4-dichlorodiphenyl sulfone production capacity is generally adequate,but it is limited by the shortcomings of the traditional 4,4’-dichlorodiphenyl sulfone preparation process,which has the problem of unstable product quality.As a monomer raw material for polysulfone,the purity of 4,4-dichlorodiphenyl sulfone raw material must be of stable and reliable quality,and the quality paramefers must meet the requirements.The content of this study is planned to improve from the sulfoxide chloride method,compare the advantages and disadvantages of the process route,and design an optimized alkylation catalyst from the perspective of economic benefits cost and environmental protection.Lewis acidic ionic liquids offer the designability of both Lewis acidic and ionic liquids.In recent years,Lewis acidic ionic liquids have attracted more and more attention as catalysts for Friedel-Crafts alkylation reactions,and good results have been achieved in the application of Lewis acidic ionic liquids,and the application prospects of Lewis acidic ionic liquids have been expanded.Lewis acidic ionic liquids were used as catalysts for the alkylation of chlorobenzene with chlorosulfoxide to prepare 4,4’-dichlorodiphenyl sulfoxide,which was then oxidized by H₂O₂ to produce 4,4’-dichlorodiphenyl sulfoxide.The amount of catalyst is reduced and the ionic liquid can be recycled,which is in line with the original intention of environmental protection.In this work,metal-based 1-butyl-3-methylimidazole chloride salt ionic liquid catalysts and heteropolyacid ionic liquid catalysts were synthesized.The catalytic performance and selectivity of different catalysts for the Friedel-Crafts alkylation reaction of chlorobenzene/SOCl₂ were examined.Kinetic analysis was also performed and reliable reaction pathways were proposed.The main studies are as follows.1.Metal-based ionic liquids with different metal chloride salt additions and different Al Cl₃ contents were synthesized for the chlorobenzene/SOCl₂ alkylation reaction.The structure,stability,acidity and acid strength of the prepared metal-based ionic liquid catalysts were characterized and analyzed by FT-IR,Py-IR,TG,¹H NMR and UV spectroscopy,and the catalytic effect of metal-based ionic liquids on and synthesized composite metal-based ionic liquids for the chlorobenzene/chlorinated sulfoxide alkylation reaction were investigated.The effect of Lewis acidity and Br?nsted acidity on the alkylation reaction of chlorobenzene/SOCl₂ was investigated by adding metal chloride salts to Al Cl₃.And Al Cl₃ was selected as the catalyst for the kinetic analysis of the chlorobenzene/SOCl₂ alkylation reaction.2.Different heteropolyacid ionic liquid catalysts were synthesized for the chlorobenzene/SOCl₂ alkylation reaction.The structure,stability,acidity and acid strength of the prepared heteropolyacid ionic liquid catalysts were characterized and analyzed by FT-IR,SEM,TG,XRD and UV spectroscopy to investigate the catalytic effect of different heteropolyacids and ionic liquid oxidation on the chlorobenzene/chlorinated sulfoxide reaction.The catalyst with the best catalytic fuction,HPMo-[Bmim]Cl-Al Cl₃,was also screened for kinetic analysis and a possible reaction mechanism was proposed.