Study On The Synthesis Of Anthraquineone From Phthalic Anhydride And Benzene On Solid Acid Catalyst

In this paper, the synthesis of anthraquineone (AQ) from phthalic anhydride (PHA) and benzene (BEN) on solid acid catalysts, as a green process for producing anthraquineone, was studied. The details are given as follow:A rapid and precise GC analysis method for the reaction system was developed, with dimethyl brassylate as an internal standard and SE-30, OV-101 and PEG-2000 columns.Several solid catalysts were prepared for the Friedel-Crafts acylation reaction of synthesis of anthraquinone. Performances of the catalysts were examined, and the better catalysts for this reaction was determined as SiO₂-Al₂O₃ with Si/Al=55/45 and SO₄^2-/TiO₂. A reaction mechanism was suggested by characterizing the catalysts with NH3-TPD and Py-IR.Effects of reaction conditions on performance of the catalyst SiO₂-Al₂O₃ with Si/Al=55/45 were investigated. Optimal conditions for the reaction were obtained. For the liquid phase reaction, the optimal conditions are as follow: particle size 40-60 mesh, PHA:BEN=l:25(mol), cat.:PHA=l:l(wt), reaction temperature 220℃ and reaction time 3h. Under the conditions above the selectivity and yield of AQ were 59.37% and 4.54%, respectively. Under the optimal conditions of the gas phase reaction as cat.:PHA=l:l(wt), reaction temperature 300℃ the yield of AQ reached to 22.55%. The stability of the catalyst was examined and it was found that the activity of the catalyst after regenerated three times decreased to one half of the fresh catalyst's. The reason of the catalyst deactivation was determined by characterizing the fresh and used catalysts.The catalyst SO₄²/TiO₂ was modified using MoO₃ as a promoter, and the catalyst activity was enhanced. Under the same conditions the yield of AQ increased to 7.1 % over the modified catalyst, compared with the value of 4.54% obtained over the un-modified catalyst.Studied the performances of solid acid catalysts for producing anthraquineone from2-benzoybenzoic (BBA), and found that HPW catalyst was the best one of the catalysts studied. The factors influencing the catalyst performance were investigated and the main factor was determined as the amount of the catalyst. Optimal conditions for the reaction were obtained as cat.:BBA= 1:20, reaction temperature 200°C.