Study on Friedel-Crafts Acylation of Benzene with Phthalic Anhydride Catalyzed by Ionic Liquids
|School||Hebei University of Technology|
|Keywords||Phthalic anhydride O - benzoyl benzoic acid Friedel-Crafts acylation reaction Heteropoly acid Ionic liquids|
Friedel-Crafts acylation reaction of benzene with phthalic anhydride is one of the main methods of synthesis of anthraquinone , traditionally the reaction AlCl3 as a catalyst , but will cause corrosion of the equipment , environmental pollution and other issues . Friedel-Crafts acylation reaction of ionic liquid benzene and phthalic anhydride , has important theoretical significance and application value . This paper examines the Keggin type heteropoly acid - phosphotungstic acid , phosphorus of molybdate and silicon tungsten acid acylation reaction of benzene with phthalic anhydride in catalytic activity , which activity is better catalyst for the phosphotungstic acid . Determine the phosphotungstic acid roasting temperature of 150 ° C , the better the reaction conditions as follows: reaction temperature of 130 ° C , reaction time 2h , m ( phthalic anhydride ) : v ( benzene ) = 3:40 m ( phosphotungstic acid ) : m ( phthalic anhydride) = 1:5, o - benzoyl benzoic acid in a yield of 7.6% under this condition . Experimental prepared the phosphotungstic acid aluminum , phosphorus and potassium tungstate and phosphotungstic cesium and investigated their catalytic activity in the reaction of benzene with phthalic anhydride acylation . The experimental results show that only the phosphotungstic acid cesium has a lower catalytic activity , o - benzoyl benzoic acid yield LT ; 1 % . Preparation of a non- chlorine Ionic liquids and chloroaluminate ionic liquid ([Emim] Br-AlCl3), and used for the catalytic benzene and phthalic anhydride acylation reaction . Experiments found only chloroaluminate ionic liquid catalytic activity . Chloroaluminate ionic liquid catalyst optimization of reaction conditions , the optimum conditions : the reaction temperature is 30 ℃ ℃ , reaction time 3h , n ( benzene ) : n ( PHA) = 3:1 , m ( [Emim Br -AlCl3 ) : m (PHA ) = 7:1, o-benzoyl benzoic acid yield of 88.4% . And speculated that the reaction mechanism . Preparation of activated carbon as a carrier supported chloride ionic liquids ([Emim] Br-AlCl3 / C), and used for the catalytic benzene and phthalic anhydride acylation reaction . Determine the catalyst impregnation time is 16h. Jiaoyou reaction conditions : reaction temperature of 80 ° C , reaction time 4h , m (PHA ) : v ( benzene ) = 1:50, m ( chloroaluminate ionic liquid ) : m (PHA ) = 10.5:1 , the conditions under the yield of benzoylbenzoate 17.8%. The supported catalyst first reuse , BBA yield dropped to 9.0 % by the supplement of the active ingredient can be BBA yield increased to 12.4% .