Study On Green Catalysis Of Anthraquinone Synthesis By Solid Acid

Friede-Crafts acylation is a typical acid-catalyzed reaction,which has important development prospects in the fields of petrochemicals,perfumes,dyes and other fields.However,traditional acid catalysts mainly include Lewis acid catalysts such as AICl3 and proton acid catalysts such as H2SO4 and HF.During the production process,a large amount of aluminum-containing and acid-containing wastewater will be generated,which will cause serious environmental pollution.In this paper,anthraquinone synthesis reaction was studied as a probe reaction by using solid acid catalysts instead of traditional AlC13,H2SO4 catalysts for green catalytic synthesis of anthraquinones,and the process conditions was optimized in order to propose a green,safe and efficient anthraquinone production process.The main contents are as follows:(1)Heteropoly acid was used as a catalyst to catalyze the dehydration of BBA to anthraquinone.HPW had the best catalytic activity for this reaction.Aiming at the problems of the large viscosity of the BBA synthesis reaction and the difficulty of reusing the catalyst,the effects of different reaction conditions on the yield of anthraquinone were explored under solvent conditions.The research results show that HPW has the best catalytic activity when sulfolane was used as the solvent,the yield of anthraquinone can reach 89.6%,and the selectivity can reach 89.98%.Compared with the solvent-free reaction,the catalyst has better reusability.However,the use of pure HPW catalyst has a small specific surface area(only 7.1 m2/g)and the catalyst recovery rate was low.(2)HPW/SiO2 catalyst prepared by the impregnation method has better specific surface area(155.2 m2/g)and thermal stability,thereby improving the catalytic activity of the catalyst and achieving catalyst recycling.The optimized reaction conditions were obtained with sulfolane as the solvent:calcination temperature 250?,calcination time 2 h,HPW loading 50%,reaction temperature 200?,reaction time 2 h,mBBA:mcat=1:1,mBBA:msolvent=1:9,the yield of anthraquinone can reach 91.12%,and the selectivity can reach 92.33%.Compared with pure HPW catalyst,the catalyst has better reusability.After four times of reuse,the catalyst's catalytic activity only decreased by 17.44%,and carbon deposition deactivation was the main reason for the decline in catalyst performance.(3)A fixed-bed reactor was designed and used for anthraquinone synthesis reaction.A solid acid catalyst was used to study the one-step synthesis of anthraquinone in the phthalic anhydride method.Using phthalic anhydride and benzene as raw materials and H? zeolite molecular sieve as catalyst,the optimal reaction conditions were reaction temperature 300?,weight hourly space velocity(WHSV)of benzene is 10 h-1,the yield of anthraquinone can reach 18.91%,and the H? zeolite molecular sieve has good reusability.