Study On Synthesis Of4-isobutyl Chloropropiophenone From Friedel-crafts Acylation Of Isobutylbenzene

Friedel-Crafts acylation is the primary method for the preparation of aromaticketones,which involves the employment of metal chlorides as the acid catalysts.Thoseenvironmentally unfriendly catalysts have always been an issue in the long-termapplication in industries. Therefore, the study of developing new catalysts for theFriedel-Crafts acylation to form aromatic ketones been important and critical.In the present dissertation, anhydrous AlCl3has been used as catalyst forFriedel–Crafts acylation of isobutylbenzene, the process conditions has beensummarized to provide a reference for the investigation of new catalysts which wereexpected to be used under the original conditions.In the third chapter of this thesis, three kind of ionic liquids has been synthesized,the solubility and catalytic activity with different amount of metal halides has beenstudied. The result showed that, according to the solubility, the catalysts can be reusedafter being extracted from the reaction system with appropriate solvent. The content ofmetal halide has a great impact on the catalytic activity of ionic liquids, the catalystshowed a highest activity when the metal halide content reached0.7and the yield ofthe product is64.9%at this moment.In the fourth chapter, A series of solid superacids such as sulfated zirconia andsulfated titania has been synthesized and characterized by Hammett indicator,meanwhile all the prepared superacids were used as catalysts for Friedel–Craftsacylation of isobutylbenzene under the same conditions to filter out the one withhighest activity for further study. The results showed that among all the prepared samples the catalytic performance of sulfated zirconia was the best. Strong Lewis acidare easier to form because of the low electrically negative of Zr, and the atomiccoordination8made it more likely to be an unsaturated ligand situation.In the fifth chapter, The catalyst of sulfated zirconia was modified byincorporating appropriate amounts of Al2O3and the effect of Al content on theperformance of the catalysts has been investigated, meanwhile the catalysts werecharacterized by means of XRD and BET. The result showed that the incorporation ofAl enhances the catalytic activities and properties prominently owing to an increase ofsurface area and stability of active tetragonal zirconia. The activity inereased by about34%(from50%to67%).The reusability of modified catalyst were studied with a method of calcined afterimpregnating, the result showed that, adsorption capacity for SO24was decreased withthe stability of catalyst crystalline structure, and the catalytic performance decreasedslightly as the loss of SO24.