Preparation Of 2-ethylanthraquinone Catalyzed By Alkali And Acid Modified H-beta Zeolite Catalyst

As one of the important industrial raw materials,2-ethylanthraquinone is widely applied in the industry to prepare hydrogen peroxide in a large scale.AlCl₃ and H₂SO₄are often used as catalysts to prepare 2-ethylanthraquinone in industry,in which lots of waste water may be generated and cause adverse influence on the environment.In order to solve such a problem,it is necessary to use more economic and environmental friendly solid acid catalysts to catalyze and synthesize2-ethylanthraquinone.As a kind of synthetic solid acid catalyst,zeolite has the advantages of environmental protection and good regeneration,the basic crystal structure of?zeolite was introduced in our work and it was used as catalyst to catalyze the dehydration reaction of 2-?4'-ethyl benzoyl?benzoic acid?BE acid?to form2-ethylanthraquinone?2-EAQ?.The optimal reaction conditions for dehydration of BE acid catalyzed by?zeolite catalyst was obtained.The optimal reaction temperature and reaction time for no-solvent system was 230?for 1.5h.The mass ratio between catalyst and BE acid was 1:2.And then the H-?zeolite was modified to improve catalytic activity for dehydration of BE acid.The modified H-?zeolites were characterized and their activity were tested.Zeolite structure was dissolved partially when treated by NaOH and ammonium hydroxide,resulting in reduction of crystalline and formation of mesoporous structure.After alkali treatment,total acid contents of samples and weak acid contents were decreased.It generated non-framework alumina ions,while obtaining mesoporous structure,thus reactivity and yield of samples after alkali treatment were lower than untreated samples.In order to eliminate non-framework alumina ions produced by alkali treatment and improve product yield,samples conducted alkali treatment were modified with citric acid,which was able to insert non-framework alumina ions in the skeleton to improve zeolite crystalline and enhance strong acid centers of zeolite molecular sieve,resulting in the increase of strong acid contents and reduction of total acid contents.After alkali treatment and citric acid treatment,the above-mentioned samples present the better catalytic activity and the conversion rate and yield can be improved.Treated by ammonium hydroxide followed by citric acid modification,the?zeolite showed improved performance..Meanwhile,ammonium hydroxide treatment had no need to do ammonium exchange,showing simple preparation and cheap costs.