Kinetics of the dehydrogenation of ethylbenzene to styrene over unpromoted and K-promoted model iron oxide catalysts

摘要: The dehydrogenation of ethylbenzene to styrene over unpromoted and potassium-promoted model iron oxide catalysts has been studied using ultrahigh vacuum techniques in conjunction with elevated pressure reaction kinetics. Model were prepared by oxidizing a polycrystalline Fe sample that was subsequently dosed metallic potassium. At 875 K the catalyst exhibited turnover frequency 5×10−4 molecules/ site s an activation energy 39 kcal/mol, both excellent agreement results found for analogous powder catalyst. Potassium promotion increased 1.0×10−3 molecules/site lowered 36 kcal/mol reaction. Similarities between energies on promoted indicate active is same catalysts. Creation dependent upon formation Fe3+ metastable species, consistent KFeO2 phase, addition