Application Of Ionic Liquids In Synthesis Of 2-Ethylanthraquinone

The chloroaluminate ionic liquids were used to catalyze Friedel-Crafts acylation of ethylbenzene with phthalic anhydride to synthesis 2-(4-ethylbenzoyl) benzoic acid. Acetonitrile was utilized as an FT-IR probe to determine the acid types and Lewis acid strength of the ionic liquids. The effects of reaction conditions such as the proper proportion between [bmim]Cl and AlCl3 in the ionic liquid,the molar ratio of ethylbenzene and phthalic anhydride, reaction temperature, reaction time were investigated. When [bmim]Cl-AlCl3 was used as the Lewis catalyst, phthalic anhydride conversion of 100% and 2-(4-ethylbenzoyl) benzoic acid selectivity of 97.14% could be obtained at the reaction condition of ethylbenzene: phthalic anhydride molar ratio was 1:1, reaction temperature was 50℃and reaction time was 4h.The results showed that ionic liquids exhibited better catalytic performance for synthesis 2-(4-ethylbenzoyl) benzoic acid than theLewis acid catalyst.A series of supported ionic liquids were prepared by impregnation method. The catalysts were characterized by means of FT-IR,BET,SEM and XRD. The supported ionic liquids were used to catalyze the Friedel-Crafts acylation of ethylbenzene with phthalic anhydride. The supported materials, preparation temperature, preparation loading of ionic liquids, reaction temperature, and catalyst dosage were studied. The results showed that the best preparation conditions of catalyst were SiO2 as supported material, 50℃, P=0.83. The supported ionic liquids catalyst exhibited higher activity and selectivity for the acylation reaction. Under optimal conditions: catalyst dosage W=18%, reaction temperature 80℃, conversion of phthalic anhydride and selectivity to 2-(4-ethylbenzoyl) benzoic acid can reach 100% and 91.1%. After regeneration, the catalyst could be used repeatedly. Supported ionic liquids were solid phase, thus they could be separated and recovered easily. A carbocation mechanism for synthesis of 2-(4-ethylbenzoyl) benzoic acid catalyzed by [Bmim]Cl-AlCl3/SiO2 was proposed.The dehydration of 2-(4-ethylbenzoyl) benzoic acid(BE acid) into 2-ethylanthraquinone (2-EAQ) was investigated over oleum. Different feed in methods and the reaction conditions were studied in detail. Under optimized conditions, the conversion of BE acid could reach 100% , and the selectivity to 2-EAQ was up to 86%.