Study On Oxidative Dehydrogenation Of Propane To Propylene Over Vanadium Based Catalysts

In this paper,γ-Al₂O₃,SiO₂,TiO₂,ZSM-5 and Y were used as carrier respectely,V was used as the active component,and boron（B）and magnesium（Mg）were added as modification additives,series vanadium loadings catalysts were prepared by impregnation,and the catalytic performance for propane oxidative dehydrogenation.characterized by XRD,Raman,and cyclic voltammetry（CV）,FT-IR and micro-reactor.the result show that:1.V₂O₅ crystals appear on xV-γAl₂O₃,xV-SiO₂,xV-ZSM-5 catalyst,V₂O₅crystals do not appear on xV-Y molecular sieve,xV-TiO₂ catalyst,and V-O-V appears on xV-γAl₂O₃,xV-SiO₂ catalyst.Bond and V=O bond and V-O-Al bond and V-O-Si bond appear.xV-TiO₂and xV-Y molecular sieve catalysts only show V-O-Ti bonds,V-O-Al bonds,and V-O-Si bonds.V-O-B bond and V-O-Mg bond appeared after adding B and Mg additives.2.Cyclic voltammetry was used to determine vanadium-based catalysts.With the increase of vanadium loading,the reducing properties of xV-γAl₂O₃,xV-TiO₂,xV-SiO₂,xV-ZSM-5,and xV-Y molecular sieve catalysts and the structure of vanadium oxygen species Its degree of dispersion is closely related.3.FT-IR measurement shows that the gradual increase of the CO₂ vibration peak may be due to the oxidation of propane in oxygen,or the C-H bond in propane is broken into other carbon compounds to form CO₂.4.The propylene selectivity of xV-γAl₂O₃,xV-TiO₂,xV-SiO₂,xV-Y molecular sieves,and xV-ZSM-5 catalysts were 75.9%,87.82%,73.4%,87.8%,and 53.17%,respectively.The selectivity of 3V-γAl₂O₃ catalyst gradually decreased after adding B and Mg.The selectivity of 6V-TiO₂,6V-SiO₂,and 15V-ZSM-5 catalysts gradually increased after adding B,and the selectivity gradually decreased after adding Mg.The selectivity of 15V-Y molecular sieve catalyst does not change after adding B and Mg.