共查询到20条相似文献,搜索用时 15 毫秒
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A. R. Brun-Tsekhovoi S. S. Kurdyumov A. L. Rozental 《Reaction Kinetics and Catalysis Letters》1992,47(1):37-42
Kinetics of methane conversion in a fluidized bed of microspherically grained nickel-alumina catalyst has been studied at pressures from 0.3 to 3.1 MPa. The rate equation shows that the reaction is inhibited by H2O.
0,3 3,1 . , .相似文献
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L. M. Kustov O. P. Tkachenko 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(12):2005-2012
Methods for preparing catalysts for the oxidative condensation of methane based on a metal support (FeCrAl foil) containing Al2O3 and SiO2 and active ingredients (Na2WO4, Mn2O3, and PbO) are developed. The prepared catalysts are studied by XRD, XPS, and EM. 相似文献
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Ternary systems of inorganic Pt salts and oxides, ionic liquids and concentrated sulfuric acid are effective at catalyzing the direct, selective oxidation of methane to methanol and appear to be more water tolerant than the Catalytica reaction. 相似文献
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Megumu Inaba Kazuhisa Murata Masahiro Saito Isao Takahara Naoki Mimura 《Reaction Kinetics and Catalysis Letters》2002,77(1):109-115
Hydrogen production by conversion of methane over Ni-supported zeolite catalysts was investigated, and Ni-supported USY-type zeolite (Si/Al2 = 14.0, 360) was found to have longer catalytic lifetime than Ni-supported silica (Cab-O-Sil) catalyst, which had been reported to have the longest catalytic lifetime for this reaction. 相似文献
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CH2O conversion over sodium-manganese oxide and oxychloride catalysts in methane dehydrodimerization have been studied under unsteady-state conditions at high temperatures (600–750 °C). It has been established that formaldehyde conversions produce deep oxidation (CO, CO2), condensation (C2H4, C2H6) and methanation products through CH3O– formation and decomposition.
(600–750°C) CH2O - . , (CO, CO2) (C2H4, C2H6), , CH3O–.相似文献
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L. L. Korobitsyna N. V. Arbuzova A. V. Vosmerikov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(6):919-922
High-silica zeolites of ZSM-5 structural type were synthesized using various structure-forming additives and without them. Mo-containing catalytic systems were prepared on the basis of these zeolites. Their physicochemical properties and activity in the course of the nonoxidative conversion of methane were studied. The Mo/ZSM-5 catalyst obtained on the basis of zeolite synthesized with hexamethylenediamine showed high aromatizing activity and stability. 相似文献
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《Journal of Energy Chemistry》2010,(5)
Rh/SiO2 was prepared for the oxidative bromination of methane. The catalyst was prepared by calcination at different temperatures and for different times to obtain catalysts with different specific surface areas for the purposes of producing either CH3Br or CH3Br and CO. It was found that the catalyst having a low specific surface area (calcined at relatively high temperature) favors the selective oxidation of methane to prepare CH3Br, while the catalyst having a high specific surface area favors the deeper partial oxidation of methane, which is good for CH3Br and CO preparation.The 650 h on stream life-time test revealed that the catalytic performance of the 0.4Rh/SiO2-900-10 catalyst was excellent.Both methane conversion and CH3Br selectivity kept increasing trends during the life-time test.No matter how serious was the Rh leaching during the reaction,the 0.4Rh/SiO2-900-10 catalyst did not deactivate at all. 相似文献
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考察了具有相同金属分散度的Pt/NaY、Pt/HNaY、 Pt/HY、Pt/NaBeta和Pt/HBeta催化剂中沸石载体的酸性对在低温下(≤250 ℃)甲烷两步等温转化反应以及由甲烷解离吸附产生的表面碳物种分布的影响。由甲烷等温两步转化生成的C2+烃类产物的总量随着载体酸性的增加而明显增加;C2~C6产物的分布也发生了变化。由表面碳物种的程序升温加氢结果表明,在各种催化剂上碳物种的形式是相似的,其总量和具有活性的Cα物种的量均因载体酸性增加而增加,反应性也增大。这种因沸石载体酸性变化而引起的载体效应是由金属和载体的相互作用造成负载在酸性载体上铂粒子的贫电子性而引起,即由金属粒子电子性质的变化而引起的催化性质的变化。 相似文献
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A. N. Shigapov M. A. Novoshilova S. N. Vereshchagin A. G. Anshits V. D. Sokolovskii 《Reaction Kinetics and Catalysis Letters》1988,37(2):397-402
Experimental data for the oxidative dimerization of methane over CaO–CaCl2 systems indicate that C2 hydrocarbons are formed with the participation of chlorine generated by the catalyst surface under the effect of a reaction medium. A heterogeneous-homogeneous scheme for this process is suggested.
CaO–CaCl2 , C2- , . - .相似文献
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A. V. Vosmerikov V. I. Zaikovskii L. L. Korobitsyna G. V. Echevskii V. V. Kozlov Ya. E. Barbashin S. P. Zhuravkov 《Kinetics and Catalysis》2009,50(5):725-733
The nonoxidative conversion of methane into aromatic hydrocarbons on high-silica zeolites ZSM-5 containing nanosized powders
of molybdenum (4.0 wt %) and nickel (0.1–2.0 wt %) was studied. Data on the acid characteristics of the catalysts and the
nature and amount of coke deposits formed on the surface of the catalysts were obtained using the thermal desorption of ammonia
and thermal analysis. The microstructure and composition of Ni-Mo/ZSM-5 catalysts were studied by high-resolution transmission
electron microscopy and energy-dispersive X-ray analysis. The formation of various chemical species in the samples was detected:
oxide-like clusters of Mo within zeolite channels (∼1 nm), molybdenum carbide particles (5–30 nm) on the outer surface of
the zeolite, and Ni-Mo alloy particles with different compositions (under reaction conditions, carbon filaments grew on these
particles). It was found that, as the Ni content was increased from 0.1 to 2.0 wt %, the rate of deactivation of the catalytic
system increased because of blocking pores in the zeolite structure by filamentous carbon up to the formation of condensed
coke deposits. 相似文献
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The kinetics of the oxidative coupling of methane (OCM) in the presence of La/MgO and NaWMn/SiO2 catalysts in a flow reactor at low reactant conversions was studied. It was found that, in spite of different compositions and properties of the test catalysts, the formation of ethane from methane and ethylene from ethane can be described within the framework of the Mars-van Krevelen redox model in both cases. The rate laws of side reactions, which lead to the formation of carbon oxides, are different from the rate laws of the target reactions of the conversion of methane into ethane and ethane into ethylene. The kinetic parameters required for the numerical simulation of the OCM process were determined for either of the catalysts. 相似文献
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Alumina supported Ru nanoparticles, with an initial average size of 5.8 nm, show high activity and yield to CO and H2 at lower temperature than the conventionally prepared catalysts.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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V. P. Zhereb E. N. Voskresenskaya L. I. Kurteeva V. F. Kargin A. G. Anshits 《Reaction Kinetics and Catalysis Letters》1993,50(1-2):327-332
Bi2EO5 (E=Si, Ge) catalysts in a metastable state have been found to possess a high activity for oxidative coupling of methane. It has been assumed that the intergrowth boundaries for the Bi2EO5 decomposition products, on which active catalytic sites may be located, play a specific role on the catalytic performance of the oxides. 相似文献
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Jacob J. Piane Steven Huss Lucas T. Alameda Stephen J. Koehler Lauren E. Chamberlain Matthew J. Schubach Ashley C. Hoover Elizabeth Elacqua 《Journal of polymer science. Part A, Polymer chemistry》2021,59(22):2867-2877
Single-chain polymer nanoparticles (SCNPs) are emerging as versatile catalytic platforms that provide excellent control over solubility. The confined nature of SCNPs can improve the rate of catalysis. While significant headway has been made in thermally-induced transition-metal catalysis with SCNPs, light-activated SCNP catalysts have received little attention. We are developing triarylpyrylium tetrafluoroborate (TPT)-functionalized SCNPs as oxidative photocatalysts. Herein, we comprehensively study the impact of light source on both SCNP compaction and TPT absorbance through gel-permeation chromatography and UV/Vis spectroscopy. We observe that compaction is expedited using light sources that excite the photocatalyst (e.g., blue LEDs), which is attributed to the ability of TPT to dimerize sytrenics under similar photoredox conditions. The resultant metal-free SCNP photocatalysts enable the oxidation of benzyl alcohols in good yields. The SCNP is further investigated for the amidation of 4-bromobenzaldehyde, wherein it affords higher yields of the benzamide product compared to both small-molecule and unfolded polymer controls. We attribute the combined results to the colocalization of the TPT photoredox catalyst and pyrene electron relay within the SCNP, which likely aids in single-electron transfer processes. The scope of amidation reactions was also extended to other aryl aldehydes, wherein deactivated substrates afforded the highest yield of the desired amide. 相似文献
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S. N. Vereshchagin E. V. Kondratenko E. V. Rabchevskii N. N. Anshits L. A. Solov’ev A. G. Anshits 《Kinetics and Catalysis》2012,53(4):449-455
A new approach to the preparation of systems that exhibit catalytic activity in the oxidative coupling of methane (OCM) is considered. With the use of ferrospheres separated from power-generation ashes from different sources as an example, it was demonstrated that OCM catalysts can be prepared by the crystallization/solidification of oxide melts with the formation of microspherical particles. The dependence of activity and selectivity for the oxidative reforming of methane on the ferrospheres containing from 36.2 to 92.5 wt % Fe2O3 into the products of deep oxidation and OCM was studied. It was found that deep oxidation reactions on ferrospheres with Fe2O3 contents higher than 85% were suppressed, and the main reaction path of CH4 conversion was its oxidative coupling with the formation of C2 products (with selectivity to 60% at 750°C); moreover, the selectivity for C2 formation in this region was proportional to the concentration of Fe2O3. Phases responsible for the catalytic conversion of methane into CO x and OCM products were considered, and it was shown that the catalytic activity and selectivity of the oxidative transformation of CH4 on ferrospheres is determined by the position of the point that corresponds to their composition on a phase diagram of CaO-Fe2O3-SiO2. 相似文献
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Pavlina Kovacheva Katya Arishtirova Albena Predoeva 《Reaction Kinetics and Catalysis Letters》2003,79(1):149-155
The oxidative methylation of toluene with methane is used as a test reaction for determining the activity, selectivity and
yield of C8 hydrocarbons (ethylbenzene and styrene) over different zeolite and zeolite-type catalysts, viz., X, Y, mordenite, ZSM-5, silicalite and AlPO4-5. Selectivity and basicity increase with decreasing Si/Al atomic ratio within the series of the same structural type. The
basicity, surface structure and structural integrity are characterized by TPD of CO2, XPS and IRS, respectively.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献