Study On The Catalysts Applied In Ethylbenzene Dehydrogenation In The Presence Of Carbon Dioxide

Dehydrogenation of hydrocarbons is one of the challenges in thepetroleum chemical industry, since it is often confined by the thermodynamicequilibrium. Styrene, one of the monomers of synthetic polymers, is mainlyproduced by the dehydrogenation of ethylbenzene under high temperature,leading to the high operation cost and excessive energy consumption.Recently, in the process of oxidative dehydrogenation, CO₂ is taken as anoxidant instead of O₂, which is an effective way to reducing energyconsumption and decreasing CO₂ pollution. It is important to study newtechnology in preparation of high effective catalysts.In the present work, ethylbenzene conversion on different atmospherewas calculated, which gave guidance to experiments.The sol-gel method was used to prepare VxT mixed oxides catalysts,which TiO₂ was the main body and the catalysts were applied withethylbenzene dehydrogenation in the presence of carbon dioxide at 450℃.And we get Fex/V6T by add promoter Fe. By means of XRD, XPS, TG-MSand physical adsorption techniques, the catalysts were characterized. Several significant results and conclusions were obtained as follows:1) It was found that CO₂ was attributed to the increase of EB conversion.2) V6T catalyst revealed a very excellent activity in CO₂-EBDH, theconversion of ethylbenzene and the yield of styrene were 11.0ï¼…and98.3ï¼…respectively at 450℃.3) Fe was added to V6T, getting Fex/V6T catalyst, which can improve theEB conversion. Fe2/V6T is the best of Fex/V6T catalysts.4) Characterization of V6T catalyst showed that V⁵⁺ could be the activecenter for the reaction. The anatase phase of TiO₂ in V₅T catalyst offeredhigher styrene selectivity, while the rutile phase sharply depressed thecapability of catalyst in the dehydrogenation of ethylbenzene.5) Catalysts deactivation is mainly caused by coke deposition and thereduction of V⁵⁺ and Fe³⁺.