Dehydration Of 2-(4'-Alkylbenzoyl) Benzoic Acid To 2-Alkylanthraquinone Over Solid Acid Catalysts

2-alkylanthraquinone is an important intermediate for the synthesis of hydrogen peroxide, pharmaceuticals,pesticides and dyes.With the increasing demands for hydrogen peroxide in the international marker,it needs to increase the production of 2-alkylanthraquinone.The traditional manufacture process which commonly catalyzed by concentrated H₂SO₄ or oleum generate a large.amount of waste acid which hazards to environments,human being and production system.On the base of the former researched work of our team,we research futher use the environmentally friendly zeolite as catalyst.The work refers to mainly three aspects.1. Further study of the effect of the molar ratio of SiO₂/Al₂O₃ and crystal size of Hβzeolite on the dehydration of 2-(4'-ethylbenzoyl)benzoic acid(BEA) into 2-ethylanthraquinone(2-EAQ); 2.Study of the reason for the loss of catalytic activity and looking for regenerating way,3. Study of the dehydration of 2-(4'-tert-butylbenzoyl)benzoic acid into 2-tert-butylanthra quinone(2-TBAQ) over solid acid catalysts.The conclusions are drawn as the followings:1.The acidity and crystal size of the catalyst affect the dehydration of BEA into 2-EAQ. At low temperature,the effect of crystal size of Hβzeolite on the reaction is obvious because the diffusion of the reactants and products controls the vdlocity of the reaction.But the catalytic performance of different catalysts is nearly the same when the effect of diffusion decreases at high temperature.2.Large molecules form in the process of this reaction which is responsibie for the loss of catalytic activity.The deactivated catalysts can be regenerated by washing with ethanol solution followed by calcination.The treated catalyst is reused for four times and it still keep. a BEA conversion of 99.5%and a 2-EAQ selectivity of 99.4%.3.Synthesis of 2-EAQ that use fixed-bed reactor is operated,a BEA conversion of 64.0%and a 2-EAQ selectivity of 60.7%is achieved.4.The process of synthesis of anthraquinone is simulated primarily by computer, reaction mechanism is deduced further.5.The dehydration of 2-(4'-tert-butylbenzoyl)benzoic acid into 2-TBAQ is carried out over Hβ,HY zeolites etc.Among the catalysts,HY shows the best catalytic performance.The performance of catalysts is strongly affected by the molar ratio of SiO₂/Al₂O₃,the best catalytic performance of HY is got over HY catalyst with the molar ratio of SiO₂/Al₂O₃ 90; The performance of HY zeolite will be improved when it is treated by citric acid solution;The increase in the reaction temperature leads to the increase in the catalytic properties.Under the optimum reaction conditions,the conversion of 2-(4'-tert-butybenzoyl)benzoic acid can reach 86.5%,and the Selectivity to 2-TBAQ is up to 85.%.