Study On The Properties Of Catalysts For Direct Alkylation Of Ethane And Benzene To Ethylbenzene

Ethylbenzene is a versatile chemical intermediate that can be used to produce various chemicals such as styrene,acetophenone,and synthomycin.The traditional way of producing ethylbenzene mainly relies on the alkylation of benzene and ethylene.The price of raw material ethylene is high,and the reaction process of ethane dehydrogenation to ethylene is high in temperature,serious in energy consumption,and high in production equipment requirements.The use of low-cost ethane instead of ethylene to produce ethylbenzene with high added value is of great significance for the rational utilization of resources and the development of ethylbenzene industry in my country.research work.First of all,the technical scheme of one-step production of ethylbenzene from ethane and benzene has well solved the problems of high dehydrogenation reaction temperature,high energy consumption,high dehydrogenation reaction temperature and high energy consumption in the catalytic dehydrogenation of ethane and the alkylation of benzene and ethylene to produce ethylbenzene.Process length,etc.On this basis,a metal-acid multi-active center catalytic model(Pt Zn Pr&ZSM-5)was proposed with Pt species as metal dehydrogenation active center,Zn and Pr as auxiliaries,and ZSM-5 as acid active center.Through the systematic regulation of process conditions and metal-acid active centers,the effects of the spatial distance of active centers,acid properties,and the regulation of auxiliaries on the reaction were studied.Combined with in situ infrared,X-ray photoelectron spectroscopy(XPS)and other characterization methods,the structure-activity relationship between the morphology and catalytic performance of the catalytic model was studied in depth.The results show that the addition of Zn and Pr additives can increase the proportion of L acid in ZSM-5 zeolite while adjusting the electronic state of the metal cluster surface.When the space distance of the active center is smaller,the ratio of L/B acid is larger,the activity of the catalyst is better.Zn and Pr modification increased the ethylbenzene yield of the catalyst by 29% and the stability for more than 50 hours.Aiming at the deactivation of the catalyst caused by the sintering agglomeration of Pt species and the coking reaction of molecular sieves,we synthesized short b-axis ZSM-5 with regular morphology by hydrothermal synthesis,establishing faster catalytic diffusion channels and high Dispersing metal surfaces to improve catalyst stability is one of the innovations of this work.The morphology and structure of the catalytic model,the structure-activity relationship between the electronic valence state of the metal surface and the catalytic performance were deeply studied by various characterization methods such as XPS and TEM.The results showed that the model catalyst constructed with short b-axis ZSM-5 as the acid active center,Pt species as the metal dehydrogenation active center,and Zn and Pr as the promoters further improved the product selectivity and stability.Aiming at the problems of high cost of noble metal catalysts and too single catalyst system,in this work,low-cost transition metals such as Fe,Co,and Ni are used as dehydrogenation active centers.By changing the carrier,changing the introduction method of the dehydrogenation active center and other means to seek an ideal catalyst system to further reduce the production cost and inhibit the metal agglomeration,and lay the foundation for the related research work on other catalyst systems for the alkylation of ethane and benzene.