Alkylation Of Benzene With Ethyl Chloride To Ethyl Benzene

Ethylation of benzene is the main method to form ethyl benzene, in industry, ethanol or ethylene is mostly used as alkylating agents, catalyzed by solid acid to alkylate directly, but less used ethyl chloride as alkylating agent to alkylate with benzene to ethyl benzene, therefore the alkylation reaction process of benzene with ethyl chloride to form ethylbenzene was investigated over chloroaluminate ionic liquid, HZSM-5 zeolites and modified HZSM-5 zeolites, and the performance differences among these catalysts were also investigated combining the catalytic reaction experiments and the characterization of the catalysts.Firstly, chloroaluminate ionic liquid was used as catalyst, and its catalytic performance on the alkylation of benzene with ethyl chloride was studied experimentally.The effect of sunch influencing factors was investigated as the anion of ionic liquids, feeding methods, the molar ratio of AlCl3 to [Et3NH]Cl, temperature, the molar ratio of benzene to ethyl chloride, the amount of ionic liquid, time and the regeneration approach of the used ionic liquid catalyst was studied.The results suggested that the feeding methods impact on the conversion of benzene and selectivity of ethyl benzene,under the same conditions, compared feeding method II to feeding method I, the former conversion of benzene and selectivity of ethyl chloride is higher.Increasing the temperature can helpt to increase the conversion of benzenen, but decrease the selectivity of ethyl benzene.It helps to increase the selectivity of ethyl benzene by increasing the molar ratio of AlCl3 to [Et3NH]Cl, the amount of catalyst and molar ratio of benzene to ethyl chloride.At optimal conditions,that is,10wt% of catalyst with benzene and ethyl chloride,2:1 of molar ratio of AICl3 to [Et3NH]Cl,70℃,10:1of molar ratio of benzene to ethyl chloride, the conversion of benzene can reach 9.48%, and the selectivity of ethyl benzene can reach 93.65%. The activity of the catalyst can be basically remained after ten times reuse. For the used ionic liquid, its catalytic activity can be recovered via adding some extra AlCl3. In the process of the whole experiment, there is a small amount of diethylbenzene and rarely triacetate benzene generated, and no xylene isomers generated.Secondly, the effect of reaction conditions on the alkylation process for ethylbenzene synthesis over the HZSM-5 zeolite catalyst was systematically discussed and the optimal reaction conditions were researched. The result shows that the appropriate operating conditions are as follows:temperature was 300～340℃, the molar ratio of benzene to ethyl chloride was 8～10 and the weight hourly space velocity was 4～6h-1. Finally, the modified HZSM-5 zeolite used as catalysts, under the same condition of unmodified HZSM-5 zeolite, that is,320℃,10:1of molar ratio of benzene to ethyl chloride,4h-1 of the weight hourly space velocity, the conversion of benzene was lower than unmodified HZSM-5 zeolite's, but the selectivity of ethyl benzene was higher.5% boron modified HZSM-5, it's selectivity of ethyl benzene was 99.27%,3% phosphorus modified HZSM-5 was 97.92%, and 1% magnesium was 96.98%. Combining the performance evaluation (activity, selectivity) and the characterization of the catalysts (XRD, TPD, FT-IRand BET), showed that the total acid quantity of modified HZSM-5 was smaller than unmodified HZSM-5, simultaneously the acid strength slightly decreased, and the surface area and pore volume decreased too, the surface acidity of zeolite catalyst is the main factor which impact on the conversion of benzene and the selvctivity of ethyl benzene.