Dehydrogenation of Ethylbenzene to Styrene over LaVOx/SBA-15 Catalysts in the Presence of CO2
|Course||Physical and chemical|
|Keywords||Ethylbenzene oxidative dehydrogenation styrene carbon dioxide LaVOx/SBA-15 catalyst vanadium -loading carbon deposition|
Styrene is a very important raw materials in petrochemical engineering.It’s monomer was mainly produced by the catalytic dehydrogenation of ethylbenzene over K- doped（or Mg,Cr,Zn etc.） hematite catalyst at 600-700℃.Due to strong endothermic effect,a large amount of superheated steam is added in this process to reduce the reactant partial pressure and to avoid coke formation.Recently,CO2 as a mild oxidant has been investigated extensively for ethylbenzene dehydrogenation. In this articles,a series of LaVOx/SBA-15 catalysts with different vanadium loadings was investigated for the dehydrogenation of ethylbenzene to styrene in the presence of CO2.The introduction of La3+ has an effect of hindering carbon deposition and enhancing the stability of the catalysts.10%La2O3-15%V2O5/SBA-15（weight%） catalyst exhibited the best activity and stability,giving a styrene yield of 74%.The properties of the LaVOx/SBA-15 catalysts were characterized and the results of TPR and TG/DTG analysis confirmed that the activity of the catalyst could be attributed to the mono-dispersion of VO43- species and synergistic action of lanthanum and vanadium.The catalysts were characterized by small and wide angle XRD,BET,H2-TPR, CO2—TPD,FT-IR,TG-DTG.