Oxidative dehydrogenation of alkylheteroaromatic compounds 1. Catalysts containing vanadium and molybdenum for the oxidative dehydrogenation of alkylpyridines

The dehydrogenation of a series of alkylpyrïdines has been studied on vanadium and molybdenum oxide-containing catalysts in the presence of oxygen of the air and sulfur dioxide gas. A dependence was shown of the catalytic and physicochemical properties of the catalysts indicated on their composition and method of preparation. The optimum catalyst composition and the conditions of carrying out the reaction to provide high activity and selectivity when making vinylpyridines were determined. The relative reactivity of the alkylpyridines investigated on dehydrogenation and further oxidation was determined.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 802–811, June, 1994. Original article submitted April 19, 1994.     

Catalytic Oxidative Dehydrogenation and O_2-Free Dehydrogenation of Isobutane on Some Molybdates

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Oxidative dehydrogenation of propane

At temperatures near 650°C and residence times ofca. 3 s, the homogeneous oxidative dehydrogenation (OXD) of propane to propylene and ethylene approached oxygen limiting conditions, even when the reactor was filled with quartz chips. The addition of catalysts that are known to be effective in the OXD of ethane slightly increased the reaction rate, but the selectivities at a given conversion level were the same as those that were achieved in the homogeneous reaction.     

Oxidative dehydrogenation of n-decane

Russian Chemical Bulletin -     

Oxidative Dehydrogenation of 4-Arylurazoles

4-Arylurazoles are selectively oxidized with Fe₂(NO₃)₃ · 9H₂O to the corresponding ¹-1,2,4-triazoline-3,5-diones.     

乙醇氧化脱氢实验的深度研究

通过实验验证和理论分析,说明教材乙醇脱氢反应的实验设计存在不足。分析研究乙醇的2种脱氢方式,认为使用氧化铜欠妥,在此基础上提出了较为科学、合理的实验设计。     

Oxidative dehydrogenation of dihydropyrimidinones and dihydropyrimidines

[reaction: see text] A mild, practical procedure for oxidative dehydrogenation with catalytic amounts of a Cu salt, K2CO3, and tert-butylhydroperoxide (TBHP) as a terminal oxidant has been developed. This oxidation procedure is generally applicable to dihydropyrimidinones and most dihydropyrimidines.     

铁系催化剂上乙苯与CO2氧化脱氢反应

采用浸渍法和溶胶-凝胶法制备了三种含Mg,Fe和Al量相同的Fe2O3-MgO/γ-Al2O3,Fe2O3/MgAl2O4和MgFe0.1Al1.9O4催化剂,在580°C考察了它们催化乙苯与CO2氧化脱氢反应性能,并采用X射线衍射,表面元素分析,H2-程序升温还原和CO2-程序升温脱附等技术对催化剂体相及表面性质进行了表征.结果表明,催化剂制备方法影响Fe物种的存在形态,进而影响催化剂的稳定性和活性.采用浸渍法制备的Fe2O3/MgAl2O4催化剂含有高度分散的Fe2O3活性物种,该物种具有较好的初活性,但是稳定性较差;而采用溶胶-凝胶法制备的MgFe0.1Al1.9O4催化剂中,Fe物种主要以同晶取代的形式存在于尖晶石骨架中,因而具有较高的乙苯与CO2氧化脱氢催化活性和稳定性.     

Oxidative Dehydrogenation of 1-Butene Over Magnetite

Magnetite (FC₃O₄), a partially reduced iron oxide, has long been considered as inactive in the oxidative dehydrogenation of butene. By studying a clean Fe₃O₄ powder, we found that Fe₃O₄, similar to other spinel ferrites, is not only active, but also more active and selective than α-Fe₂O₃. The active site densities and the desorption temperatures of oxidation products on Fe₃O₄ were also measured. Fe₃O₄ is, however, unstable under flow reaction conditions. Even if the bulk of the oxide is stabilized in the form of Fe₃O₄ at high temperatures and low O₂/C₄ ratios, its surface is gradually oxidized to a form close to α-Fe₂O₃, resulting in a decrease in both the activity and selectivity. The restructuring of the FC₃O₄ surface is temperature dependent. At 300°C, the high selectivity and activity of a low-surface-area Fe₃O₄ can be long preserved even if the bulk is oxidized to α-Fe₂O₃.     

Catalytic Conversion of Methanol by Oxidative Dehydrogenation

This study investigates the effects of addition of oxygen on the oxidative dehydrogenation (ODH) of methanol when a fluorotetrasilicic mica ion-exchanged with palladium (Pd2 -TSM) was used as the catalyst. The reaction proceeded at a very low temperature in the presence of oxygen, and HCOOCH3 was obtained at high selectivity. By calculating the equilibrium conversion, it has been shown that substantial ODH took place for HCOOCH3 production. Consequently, this reaction would make dehydrogenation the dominant reaction at equilibrium. Not all the H dissociated from CH3OH was converted to H2O by oxidation. It has been shown that the H2O was not produced from oxidative dehydrogenation by the direct reaction of CH3OH and O2 when an attempt was made to carry out oxidative dehydrogenation using an isotope oxygen trace method in the gas phase. Therefore, when CH3OH was converted to CO2 and dehydrogenated to HCOOCH3, the C—O bonds were not dissociated.     

正丁烷在金属钼酸盐催化剂上的氧化脱氢

 用柠檬酸盐法合成了第一系列过渡金属(Cr,Mn,Fe,Co,Ni,Cu和Zn)及Mg的钼酸盐催化剂,研究 了它们对正丁烷氧化脱氢反应的催化作用. 结果表明,这些钼酸盐催化剂的催化性能受阳离子的影响较大. CoMoO4催化剂具有最高的催化活性和较高的选择性,其催化性能与文献报道的对正丁烷氧化脱氢反应催化性能最好的ZrP2O7和Mg3V2O8催化剂大致相当; MgMoO4催化剂虽然选择性较高,但活性较低; Cr2(MoO4)3上基本没有C4烯烃生成; 其它钼酸盐催化剂对正丁烷氧化脱氢反应的催化活性和对烯烃的选择性都较低. XRD,NH3-TPD和H2-TPR的研究结果表明,催化剂为单一的钼酸盐晶相,催化剂的性能由其氧化还原性决定而与其表面酸量没有直接关系. 通过对产物分布的分析,提出了正丁烷在CoMoO4催化剂上的氧化脱氢反应途径. 在558 ℃,正丁烷发生氧化脱氢生成正丁烯和丁二烯以及氧化燃烧生成CO2三个平行竞争反应的竞争分率分别约为75%,10%和15%. 在正丁烷转化率较高的条件下,产物中的CO2主要来自C4烯烃的再氧化反应,而CO则完全来自C4烯烃的再氧化.     

异丁烷在Cr2（MOO4）3,Fe2（MoO4）3催化剂上的无氧脱氢与氧化脱氢

研究了Ｃｒ２（ＭｏＯ４）３、Ｆｅ２（ｍＯ４）３、对异丁烷无氧脱氢与氧化氢的催化性能，在无氧脱氧反应中，催化剂的表面酸性既有利于异丁烷活性生成异丁烯，又易引起裂和异构化等副反应，在氧化脱氢反应中，异丁烯选择性较低，催化剂的表面酸中心对反应中间体的吸附将导致深度氧化。     

Design of Selective Catalysts for Oxidative Dehydrogenation

Iron phosphate catalysts possess a unique selectivity to oxidative dehydrogenation. Unlike catalysts consisting of molybdenum and/or vanadium, they have no double-bond oxygen species (M=O), which are considered to be responsible for the oxygen insertion function and, as a result, for the degradation by C–C bond fission. The defect of iron phosphate catalysts is their lack of oxidation activity. The addition of a very small amount of molybdenum to iron phosphate markedly enhances the oxidation activity without modifying the high selectivity that originates from iron phosphate.     

α-thiocyanatocarbonyl compounds. 2*. Condensation of phosphorylated α-phenyl-α-thiocyanatoacetaldehyde with phosphorus nucleophilic reagents

We are the first to report a study of the reaction of phosphorylated α-phenyl-α-thiocyanatoacetaldehyde with triphenylphosphine, dimethylphenylphosphine, and diethylphosphorous acid, which yields bisphosphorylated 4,5-thioazolidines. * For Communication 1 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1707–1711, November, 2008.     

负载型Co-Cr氧化物催化剂上CO2氧化乙烷脱氢制乙烯反应的研究

制备了一系列不同Co／Cr比例的Co-Cr／SiO2和Co-Cr／γ-Al2O3催化剂，并应用XRD等技术对所制样品进行了表征．在常压连续流动固定床石英反应器中考察了它们对CO2乙烷氧化脱氢反应的催化性能．实验结果表明，Co-Cr／SiO2和Co-Cr／γ-Al2O对CO2乙烷脱氢制乙烯都有较高的催化活性，其活性都明显高于负载单一组分的催化剂．以γ-Al2O为载体的催化剂活性明显比以SiO2为载体的催化剂活性高．1％Co-5％Cr／γ-Al2O活性最高，973K乙烷的转化率达25．57％，乙烯的选择性和收率分别达94．28％、24．10％．     

Oxidative dehydrogenation of propane over Ni-Mo-Mg-O catalysts

In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane (ODHP). The techniques of temperature-programmed reduction with H2 (H2-TPR), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600°C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOx-NiO interface as identified by XPS.