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C 4 alkanes are widely present in the liquefied petroleum gas, refinery gas and natural gas, its source, and the price is very low, the vast majority is used as fuel directly burn off, resulting in energy pole big waste. C 4 olefin (including 1 - butene, 2 - butene and 1,3 - butadiene) are important chemical raw materials, its resources are relatively scarce. Therefore by C 4 alkanes taken by catalytic dehydrogenation or oxidative dehydrogenation of high value-added the C 4 olefin either in theory or in the economy has important practical significance. C 4 alkanes widely used rely on the of its dehydrogenation catalyst research and development, which is one of the challenging task in the field of catalytic. In this thesis, the SiO 2 for the carrier, VO x as the active component, prepared by the calcination temperature was 550 ℃ under the conditions of different vanadium loading the VO x / SiO 2 catalyst. N-butane, air and nitrogen as raw materials, in a micro fixed bed reactor in the oxidative dehydrogenation reaction of n-butane, the reaction product using gas chromatography-line analysis. The catalysts were prepared by impregnation method, first of vanadium loading on the catalyst performance; catalyst then investigated under different reaction conditions on the catalytic properties of n-butane oxidative dehydrogenation of. On this basis, using the Li, K, Mg, Ca, Sr, Al, Fe, Ni, Zn, and other metal oxide on the VO x / SiO 2 catalyst to change the research, preparation of different metal-modified VO x / SiO 2 catalyst modifier type and content on the oxidative dehydrogenation of n-butane performance . Finally, XRD, FT-IR, TPD-NH3, TPR-H 2 and BET analysis techniques were used to characterize the catalyst, the active component of the catalyst composition, structure, metal valence reduction and surface acidity, these characterization results catalytic performance of the catalyst for the oxidative dehydrogenation of n-butane. Chapter VO x / SiO 2 catalyst was investigated VO x loading the the VO x / the SiO 2 catalyst catalytic performance of the VO x / SiO 2 catalyst VO x 3% load when the catalytic performance. 3 wt.% VO x / SiO 2 as a catalyst, the reaction temperature is 550 ° C, the feed gas n-butane / O 2 / N 2 = 4/4/42, space velocity WHSV = 1.5 × 104 ml · h -1 g cat -1 of the conditions available under the n-butane conversion rate of 45.1% and 18.6% of C 4 olefin yield. ScS life of the catalyst and under this condition, the reaction of n-butane conversion after 3 hours from 45.9% to 42.3%, and then remains substantially constant, the catalyst demonstrated good stability. By XRD, FT-IR, TPR-H the 2 tPD vs.-NH 3 and other characterization methods investigated the VO x load amount of the catalyst structure, reduction, the surface acidic characteristics, and found that the key cooperate with the activity of the catalyst surface vanadium species with the surface of the carrier, has been improved so that the VO x of reductive, also found in lower vanadium load amount, VO x is highly dispersed on the support surface, when the VO x load exceeds a certain range, the surface of the carrier to V << / sub> sub> 2 O 5 crystal. Catalyst in the presence of Si-O-V key, V = O bond and V-O-H key. The SiO 2 surface acidic sites, no catalytic activity, the increase in the amount of As the VO x load, the surface acidic sites of the catalyst in the active vanadium species increased, thereby enhancing the activity of the catalyst, but also exacerbated the oxidation of n-butane depth. Chapter with Li 2 O, K 2 O, MgO, CaO, SrO, Al 2 O 3 FE 2 O 3 , NiO, ZnO and other metal oxides 3 wt% the VO x / SiO , 2 catalyst modified study, first of MgO content on the catalytic activity found appropriate amount of MgO to some extent in the VO x / SiO 2 catalyst improve the C 4 olefin yield. NiO as modifier on VO x / SiO 2 modified catalyst is more conducive to generating 1,3 - butadiene and cracked into ethylene and propylene, while the unfavorable to the formation of n-butene, while the modifier K n-butane cracking reaction is greatly exacerbated. Other modifiers in accordance with its impact on the catalytic performance can be divided into two categories: The first category is Li 2 O, CaO, SrO, ZnO, their introduction reduces the activity of the catalyst, but also greatly improve the depth of the degree of oxidation of n-butane, improve the C 4 olefin selectivity; the other for Al , 2 O 3 The Fe 2 O 3 , they not only reduces the activity of the catalyst, but also greatly increased the depth of the degree of oxidation of n-butane, C 4 olefin The selectivity is also greatly reduced. By TPR-H 2 analysis found that the to VO x / SiO 2 Add to MgO, Li 2 O, CaO other metal of SrO catalyst activity of the surface vanadium species is more difficult to be restored.
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