Dehydration Of 2-(4'-Ethylbenzoyl) Benzoic Acid To 2-Ethylanthraquinone Over Modified Hβ Zeolite Catalysts

2-Ethylanthraquinone(2-EAQ) is an important intermediate and raw material for the synthesis of hydrogen peroxide,pharmaceuticals,pesticides and dyes.With the increasing demands for hydrogen peroxide in the international market,it is necessary to increase the production of 2-EAQ.The traditional manufacture process of 2-EAQ consists of two reaction steps:Firstly,phthalic anhydride reacts with ethyl benzene to produce 2-(4'-ethylbenzoyl) benzoic acid(BEA) catalyzed by AICI₃ or HBF₄,the second step is the dehydration of BEA, which is commonly catalyzed by concentrated H₂SO₄ or oleum.In the traditional process,a large amount of waste acid is generated,which hazards to the environment,human being and production system.Therefore,an environmentally friendly process is desired.Based on the former research work of our team,we futher use the environmentally friendly Hβzeolite as catalyst in the dehydration of BEA.The work mainly refers to 3 aspects. 1.The catalytic performance of severalβzeolites synthesized with different methods was studied.2.Hβzeolite was modified with organic acid,and the effect to its catalytic performance was studied.3.Based on the above research,one-step reaction of phthalic anhydride with ethyl benzene for 2-EAQ was carried out on batch reactor and fixed-bed reactor.The conclusions are drawn as the followings:1.The catalytic activity of Hβzeolite is strongly affected by its crystal size.The smaller of the Hβzeolite particles are,the easier for the diffusion of the reactant and product molecules,and the better its catalytic acticity will be.2.Hβzeolite was impregnated with citric acid after impregnation,the rudimental citric acid and some non-framework aluminum could be washed away by deionized water,resulting in relatively smooth pores.The Hβsample washed after impregnation showed great catalytic performance in the dehydration reaction of BEA to 2-EAQ.The conversion of BEA was 96.6%,the selectivity to 2-EAQ was 96.0%.3.Organic acid with -OH functional group can cause realumination in the process of modifying Hβzeolite,resulting in proper amount of active centers.Hβzeolites modified with citric acid,tartaric acid,malic acid and propanedioic acid showed great catalytic performance in the dehydration reaction of BEA to 2-EAQ.The conversion of BEA and the selectivity to 2-EAQ were both up to 95.0%. 4.A suitable amount of acid sites with proper acid strength is needed for the dehydration of BEA to 2-EAQ.The excess of concentration and strength of acid sites would result in dehydration between two molecules;otherwise,it could not supply enough active sites.5.One-step reaction of phthalic anhydride with ethyl benzene for 2-EAQ was carried out on fixed-bed reactor and batch reactor.The highest conversion of phthalic anhydride was 16.5%,and the selectivity to 2-EAQ was 91.0%.6.The activation energy of each reaction step in the process of one-step reaction of phthalic anhydride with ethyl benzene for 2-EAQ is calculated.