Dehydrogenation Of Ethylbenzene To Styrene Over LaVOx/SBA-15 Catalysts In The Presence Of CO₂

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 VO₄^3- 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.