Preparation Of Alkylation Catalysts Based Ionic Liquid And Study Of Properties

Alkylbenzene plays an important role in production and people's life.At present,the design and synthesis of alkylation catalysts have attracted the researchers'attention.There are various problems and limitations of traditional alkylation catalysts.In industrial production,exploration and optimization have been carried out in order to solve the problems and realize the production.In recent years,the emergence of ionic liquid catalysts has revolutionized common industrial alkylation production.According to the unique physicochemical properties of ionic liquid?IL?and polymeric ionic liquid?PIL?,considering the characteristics of different olefin alkylation,different types of acidic catalysts can be designed which involve solid acid and liquid acid,and PIL type.The acid catalyst can be designed from the aspect of pore structure,specific surface area and acid site distribution.When it comes to IL acid catalyst,a monoacid type,a di-acidic type,and a mixed acid type catalyst can be designed to increase the acidity of the catalyst.In this paper,three types of catalysts were synthesized:?1?PIL-solid acid catalyst?2?solid acid catalyst loaded with IL after PIL was used as template to synthesize porous support?3?modified IL-liquid catalyst.The specific research contents are as follows:?1?Acidic ionic liquid catalysts were prepared by cross-linking copolymerization of 1-vinyl-3-butylimidazolium bromide with divinylbenzene under the structure guiding action of P123 and ion exchange.The effects of the molar ratio of monomer and crosslinker and temperature on the morphology and pores of the materials were investigated systematically.The results showed that the prepared poly ionic liquids possessed mesopores and high surface area,the active sites were dispersed in the framework highly,which facilitates the contact reaction of the reactant molecules and the diffusion and dissociation of the product,thereby exhibiting high styrene conversion?100%?and PXE yield?96.43%?in the alkylation of styrene and o-xylene.?2?The influence of polymerization solvent and P123 dosage on MPIL structure was also investigated.The effects of various catalytic conditions on olefin conversion and product yield were also studied.The results showed that as the amount of P123increased,the pore volume and specific surface area of MPIL increased.When P123was added to 4.0 g,the prepared MPIL pore volume was 1.16 cm³/g,and the specific surface area was up to 737 m²/g.Under the optimized reaction conditions,the catalyst PW/MPIL-THF?3.0 g?showed the highest styrene conversion?100%?and PXE yield?96.21%?.?3?A series of double mesoporous silica materials were successfully prepared by using P123 and PIL as structure directing agents.The HPW anion-based supported catalyst was successfully synthesized by ion exchange and applied to the alkylation reaction of styrene and o-xylene.The results showed that the synthesized porous silicon material PIL-1.0g-2 has two different sizes of pores at 3.88 nm and 6.76 nm.The prepared catalyst PIL-1.0g-2-IL-HPW displayed the superior performance in the alkylation.The stability and cycle performance is high due to the strong interaction between the active component and the carrier.?4?Modified chloroaluminate ionic liquids catalysts were prepared by modifying traditional chloroaluminate IL with FeCl₃.The results show that there are strong Lewis acid sites([Al₂Cl₇]^-and[Al₂FeCl₁₀]^-)in the modified catalyst,and the relative specific gravity of the catalyst is significantly higher than product,so it's facilitate to separate to the product and the catalyst.By studying the product bromine value of the different reaction temperature,reaction time,catalyst dosage,benzene ratio and other factors,the conversion of olefins in the reaction is observed.Under the optimized conditions?the dosage of FeCl₃ is 1.0%of AlCl₃,the molar rate of C16 and toluene is 10:1,the catalyst to olefin molar ratio is 2:1,the reaction temperature is 50°C,the reaction time is 25min?,the bromine value is 0.07 g/100 mL.The cycle experiment shows that the modified catalyst can be used for 15 times continuously in the batch reaction,which showing the superior recovery performance.In summary,according to the characteristics of ionic liquids and poly ionic liquids,considering the features of different olefin in the alkylation reactions,an acidic poly ionic liquid catalyst with mesoporous channels and a large specific surface area was prepared,which was suitable for the alkylation of styrene with o-xylene.The activity and stability of FeCl₃ modified chloroaluminate IL has improved than traditional chloroaluminate,which showing high catalytic activity in the alkylation reaction of C16with toluene.