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Artykuły w czasopismach na temat "Molybdenum oxide catalysts":
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Del Río, José Daniel, Gustavo Andrés Durán, Álvaro Orjuela Londoño, Francisco José Sánchez Castellanos i Carlos Alberto Guerrero Fajardo. "Partial oxidation of methane to formaldehyde on MoO3, Fe2O3 and ferromolybdenum catalysts". Ingeniería e Investigación 27, nr 1 (1.01.2007): 19–24. http://dx.doi.org/10.15446/ing.investig.v27n1.14773.
One of the main challenges for catalysis has been direct methane conversion to useful products such as methanol and formaldehyde. Formaldehyde is currently produced by a three-step industrial process with syngas and methanol as intermediate products. MoO3 Fe2O3, and Fe2(MoO4)3 catalysts were used with four different Mo/Fe molar ratios (0.5, 1, 1.5, 2) in this work. The ferromolybdenum catalyst was prepared by coprecipitation. Pure oxides are more active; however they are not formaldehyde selective, but carbon oxide (CO, CO2) selective. The ferromolybdenum catalysts showed better HCHO selectivity at low conversions; the molybdenum oxide content did not show increased in catalytic activity. Increased reaction temperature did not increase formaldehyde selectivity.
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Garg, Pulkit. "A Review of the Catalysts Used in Propane Ammoxidation Reaction to Produce Acrylonitrile". International Journal for Research in Applied Science and Engineering Technology 11, nr 3 (31.03.2023): 2083–103. http://dx.doi.org/10.22214/ijraset.2023.49891.
Abstract: Background: Various catalysts were studied to synthesize acrylonitrile via propane ammoxidation. The catalysts used for this process can be categorized as antimony-based catalysts, molybdenum-based catalysts, zeolites, nitride material catalysts, and other catalysts. The catalyst which was proved to be an efficient catalyst among all other catalysts is the mixed metal oxide catalyst MoVNbTe due to its high selectivity and yield.
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Klienkov, Alexey V., i Alexander A. Petukhov. "Obtaining molybdenyl glycolate using ethanol as a salting out solvent". Butlerov Communications 59, nr 9 (30.09.2019): 66–70. http://dx.doi.org/10.37952/roi-jbc-01/19-59-9-66.
The global production of propylene oxide is more than 8 million tons/year and is increasing by more than 5% annually. Almost all domestic propylene oxide (72 thousand tons/year) is produced at PJSC Nizhnekamskneftekhim (Russia) according to one of the variants of the Halcon process – epoxidation of propylene with ethylbenzene hydroperoxide (HPEB) in the presence of a molybdenum catalyst. One of the most important tasks arising in improving the process for the joint production of styrene and propylene oxide at PJSC Nizhnekamskneftekhim (Russia) is the search and development of new catalysts and catalytic systems, one of the stages of this process – the epoxidation of propylene with HPEB. The complex molybdenum catalyst used in the production of propylene oxide, having high activity and selectivity, has several disadvantages, namely: low dissolved molybdenum content, high consumption of ethylbenzene hydroperoxide for its production, and instability during storage. Thus, the problem of obtaining a catalyst with a higher content of dissolved molybdenum and increasing the stability of the catalytic complex, i.e. development of new catalytic systems with the best technological and technical and economic indicators. An analysis of the scientific and technical literature and patent publications showed that in the synthesis of a complex molybdenum catalyst, various molybdenum compounds of both organic and inorganic nature can be used. During the study, molybdenum-containing solutions based on ammonium paramolybdate and monoethylene glycol were tested, distillation distillation products prepared by distilling off excess monoethylene glycol by strengthening under vacuum. Molybdenyl glycolate was isolated by salting out with ethanol from a distillation bottoms product.
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Aghayeva, N. I., i S. A. Mammadkhanova. "DEPENDENCE OF ACTIVITY OF BINARY Mo-V-O CATALYSTS IN THE REACTION OF DEHYDROGENATION AND OXIDATION OF ISOPROPYL ALCOHOL ON ACIDIC SURFACE PROPERTIES". Chemical Problems 21, nr 4 (2023): 388–95. http://dx.doi.org/10.32737/2221-8688-2023-4-388-395.
The reaction of dehydrogenation and oxidative dehydrogenation of isopropyl alcohol on molybdenum-vanadium oxide catalysts has been studied. It found that the dependences of isopropyl alcohol conversion and propylene yields on the atomic ratio of molybdenum to vanadium in reaction of dehydrogenation of isopropyl alcohol have the form of a curve with two maxima on samples Mo-V=2-8 and Mo-V=6-4. To characterize the acidic properties of the surface of molybdenum-vanadium oxide catalysts, their activity in the reaction of butene-1 isomerization into butenes-2 was also studied. It showed that on molybdenum-vanadium catalysts the dependence of the yield of 2-butenes on the ratio of molybdenum to vanadium also had the form of a curve with two maxima. The activities of molybdenumvanadium oxide catalysts were compared with their acidic properties. It revealed that on binary molybdenum-vanadium oxide catalysts in the reaction of isopropyl alcohol dehydrogenation the increase of surface acidity led to the increase in acetone yield and the decrease in propylene yield. In the reaction of oxidative dehydrogenation of isopropyl alcohol, the increase in surface acidity led to the increase in acetone yield, while propylene yield practically did not change.
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Thrane, Joachim, Lars Fahl Lundegaard, Pablo Beato, Uffe Vie Mentzel, Max Thorhauge, Anker Degn Jensen i Martin Høj. "Alkali Earth Metal Molybdates as Catalysts for the Selective Oxidation of Methanol to Formaldehyde—Selectivity, Activity, and Stability". Catalysts 10, nr 1 (6.01.2020): 82. http://dx.doi.org/10.3390/catal10010082.
Alkali earth metal molybdates (MMoO4, M = Mg, Ca, Sr, and Ba) were investigated as catalysts for the selective oxidation of methanol to formaldehyde in the search for more stable alternatives to the current industrial iron molybdate catalyst. The catalysts were prepared by either sol-gel synthesis or co-precipitation with both stoichiometric ratio (Mo:M = 1.0) and 10 mol% to 20 mol% excess Mo (Mo:M = 1.1 to 1.2). The catalysts were characterized by X-ray diffraction (XRD), nitrogen physisorption, Raman spectroscopy, temperature programmed desorption of CO2 (CO2-TPD), and inductively coupled plasma (ICP). The catalytic performance of the catalysts was measured in a lab-scale, packed bed reactor setup by continuous operation for up to 100 h on stream at 400 °C. Initial selectivities towards formaldehyde of above 97% were achieved for all samples with excess molybdenum oxide at MeOH conversions between 5% and 75%. Dimethyl ether (DME) and dimethoxymethane (DMM) were the main byproducts, but CO (0.1%–2.1%) and CO2 (0.1%–0.4%) were also detected. It was found that excess molybdenum oxide evaporated from all the catalysts under operating conditions within 10 to 100 h on stream. No molybdenum evaporation past the point of stoichiometry was detected.
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Farooq, Muhammad, Anita Ramli i Duvvuri Subbarao. "Evaluation of the Physiochemical Properties of Molybdenum Supported Catalysts". Advanced Materials Research 488-489 (marzec 2012): 206–10. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.206.
Molybdenum catalysts supported on γ-Al2O3and γ-Al2O3-MgO mixed oxide with varying loading of MgO (5, 10, 15, 20 wt% with respect to γ-Al2O3) were prepared successfully by wet impregnation method. The physiochemical properties of these synthesized Mo catalysts were studied by various analytical techniques such as N2adsorption–desorption (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Temperature-programmed reduction (TPR).The results showed that the addition of MgO into the support affected the binding energies of the elements and reducibility of the metal oxides formed after calcination of catalyst samples due to change in metal-support interaction. Further, the characterization techniques showed that the active metal was well dispersed on the surface of support material.
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Zazhigalov, V. A., K. Wieczorek-Ciurowa, O. V. Sachuk i I. V. Bacherikova. "Mechanochemystry as advanced methodology in green chemistry for applied catalysis". Catalysis and Petrochemistry, nr 31 (2021): 1–16. http://dx.doi.org/10.15407/kataliz2021.31.001.
In this survey we have assessed how mechanochemistry techniques comply with the aims of Green Chemistry to minimise the use of environmentally damaging reactants and unwanted by-products. In the publications the preparation of vanadium-phosphorus oxides as industrial catalysts for maleic anhydride production from n-butane and perspective catalysts of phthalic anhydride manufacture by direct n-pentane oxidation were analyzed. It is shown that mechanochemical activation and synthesis reduces the amount of harmful waste used in the production of the catalyst and increases its effectiveness. Improvement of a catalyst’s properties, help limit production of harmful emissions such as carbon oxides and hydrocarbons. It was established that mechanochemical treatment can by successfully used in the process of industrial vanadium-phosphorus oxide catalysts modification or in the process of introduction in its composition of additives which lead to increase of activity and selectivity of hydrocarbons oxidation. The possibility of the mechanochemistry use in the vanadium-titanium oxide catalysts preparation which are the base catalysts in industrial phthalic anhydride production from o-xylene was determined. It was established that mechanochemical treatment of the vanadium and titanium oxides mixture permits to delete the nitrogen oxides emission in atmosphere and prepared catalysts demonstrate the same phthalic anhydride yield but at low reraction temperature. Catalysts, manufactured by mechanochemical treatment (on the base of molybdenum oxide), provide new techniques for producing compounds as exemplified by the direct oxidation of benzene to form phenol which can replace industrial two-step process from cumene or proposed process of benzene oxidation by N2O. Mechanochemistry treatment could produce catalysts which eliminated the need to use highly toxic nitrogen oxides as reducing agents. The article describes activating Cu-Ce-O catalysts which reduce the temperature of the process for removing carbon monoxide from exhaust gases and as a method for purifying hydrogen u sed in fuel cells. Finally, there is a description of mechanochemically treated catalysts, containing metals and supported on stainless steel supports which are used to remove aromatic hydrocarbons from water sewers.
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Halawy, Samih A., Mohamed A. Mohamed i Geoffrey C. Bond. "Characterization of unsupported molybdenum oxide-cobalt oxide catalysts". Journal of Chemical Technology & Biotechnology 58, nr 3 (24.04.2007): 237–45. http://dx.doi.org/10.1002/jctb.280580306.
Navajas, Alberto, Inés Reyero, Elena Jiménez-Barrera, Francisca Romero-Sarria, Jordi Llorca i Luis M. Gandía. "Catalytic Performance of Bulk and Al2O3-Supported Molybdenum Oxide for the Production of Biodiesel from Oil with High Free Fatty Acids Content". Catalysts 10, nr 2 (1.02.2020): 158. http://dx.doi.org/10.3390/catal10020158.
Non-edible vegetable oils are characterized by high contents of free fatty acids (FFAs) that prevent from using the conventional basic catalysts for the production of biodiesel. In this work, solid acid catalysts are used for the simultaneous esterification and transesterification with methanol of the FFAs and triglycerides contained in sunflower oil acidified with oleic acid. Molybdenum oxide (MoO3), which has been seldom considered as a catalyst for the production of biodiesel, was used in bulk and alumina-supported forms. Results showed that bulk MoO3 is very active for both transesterification and esterification reactions, but it suffered from severe molybdenum leaching in the reaction medium. When supported on Al2O3, the MoO3 performance improved in terms of active phase utilization and stability though molybdenum leaching remained significant. The improvement of catalytic performance was ascribed to the establishment of MoO3-Al2O3 interactions that favored the anchorage of molybdenum to the support and the formation of new strong acidic centers, although this effect was offset by a decrease of specific surface area. It is concluded that the development of stable catalysts based on MoO3 offers an attractive route for the valorization of oils with high FFAs content.
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Shilov, Ivan, Andrey Smirnov, Olga Bulavchenko i Vadim Yakovlev. "Effect of Ni–Mo Carbide Catalyst Formation on Furfural Hydrogenation". Catalysts 8, nr 11 (19.11.2018): 560. http://dx.doi.org/10.3390/catal8110560.
High-loading Ni–Mo carbide catalysts were prepared by the modified gel-combustion method under various thermal treatment conditions. All samples were studied by X-ray diffraction (XRD) analysis, which showed that the catalysts could contain cubic and hexagonal molybdenum carbides, nickel, nickel oxide and Ni–Mo solid solutions, depending on the thermal treatment conditions. Study of catalyst activity and selectivity in the hydrogenation of furfural was carried out in a batch reactor at 150 °C and hydrogen pressure 6.0 MPa. Analysis of the reaction products showed that the highest yields of 2-methylfuran (2-MF) and furfuryl alcohol (FA) were achieved using catalysts synthesized by calcination of the nickel-molybdenum-carbon precursor at 400 °С with the following reduction in a stream of hydrogen at 600 °C. The best results for production of FA with a yield of 80 mol % and 2-MF with a yield of 29 mol % were observed using Ni6MoC–SiO2 (400/600) and Ni1MoC–SiO2 (400/600) catalysts, respectively. It has been shown that the addition of nickel to the carbide molybdenum catalyst significantly increases the activity of the catalytic systems. In addition, nickel also contributes to the formation of products formed by hydrogenation of the aromatic ring tetrahydrofurfuryl alcohol (THFA) and 2-methyltetrahydrofuran (2-MTHF).
Kornic, Steven Alexander. "Spectroscopic and chemical characterisation of heterogeneous molybdenum oxide catalysts". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ33241.pdf.
Bamroongwongdee, Chanut. "Surface science studies of model oxide catalysts : molybdenum oxide on single crystal iron oxide". Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54989/.
This thesis is concerned with the study of molybdenum oxide layer deposited on a single crystal iron oxide substrate. The surface structure of an iron oxide single crystal was investigated by X-ray photoelectron (XPS), low-energy He+-ion scattering (LEIS), low-energy electron diffraction (LEED), and scanning tunneling microscopy (STM). XPS measurement reveals the presence of both Fe2+ and Fe3* oxidation states. LEED and STM results obtained from this surface were consistent with a formation of an Fe304(III) surface termination. LEED pattern and STM images reveal an hexagonal array with a periodicity of 6 A and steps in multiples of 5 A. LEIS result shows the presence of both Fe and O in the topmost layer. Well ordered epitaxial molybdenum oxide films were grown on iron oxide single crystal substrates. Their surface structure, morphology and composition were characterized by XPS, LEIS, LEED, and STM. They were prepared by depositing molybdenum oxide onto the substrate and then oxidizing it in 10"7 mbar of oxygen. In the sub-monolayer regime, molybdenum oxide formed islands of ordered structure. XPS measurement yields a Mo 3dsn binding energy consistent with the presence of Mo6*. High resolution STM images reveal a large hexagonal lattice of protrusions with a 12 A periodicity. This pattern is consistent with a p(4x4) structure. At the monolayer coverage, a (23 x 23 )R30 surface structure is produced by annealing in oxygen (107 mbar) at 973 K. STM topographies show clear hexagonal distribution with the period of 1.1 nm corresponding to the pattern observed in LEED. These results suggest that molybdenum oxide may interact with Fe304(III) to form iron molybdate which is stable on the surface.
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Zoumot, Rowaida George. "Partial oxidation of methanol to formaldehyde over molybdenum-tin oxide catalysts". Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/11094.
The vapor phase air oxidation of methanol to formaldehyde was investigated over molybdenum oxide, tin oxide and their mixtures in an integral flow reactor at atmospheric pressure between temperature of 513 and 573 K, a space time of 10-40 hr g-cat/g-mol methanol and a molar ratio of 0.04-0.1 mol CH3OH/mol air. Experiments were done under such conditions that the effects of internal and external heat and mass transfer effects were negligible. The effects of several process variables, temperature, space time and methanol/air ratio on the conversion of methanol and the selectivity of the catalyst for formaldehyde production were determined. The results indicated that the impact of the process variables on the conversion, selectivity and yield of formaldehyde were in the following decreasing order T > W/F > R. A screening study indicated the optimum catalyst composition to be 50% SnO2 and 50% MoO3, while conversion increased with temperature and W/F selectivity decreased. This catalyst proved to be highly active and selective to formaldehyde production. Selectivity and yield of up to about 100% were obtained at 100% conversion at a temperature of 553 K, a space time (W/F) of 40 g-cat/g-mol methanol per hour and a molar ratio (R) of 0.04 mol CH3 OH/mol air. The rate expression r=k1P2M 1+k1P2M2k 2PO2 was deduced assuming a steady-state involving two-stage irreversible oxidation-reduction process. It represented the experimental data satisfactorily. Arrhenius plots of the two rate constants gave activation energies of 31.7 and 18.1 kcal/g-mol.
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Kuma, Ryoji. "Studies on Transition Metal Oxide Catalysts for Waste Gas Treatment". Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263353.
Oloye, Femi Francis. "Synthesis and characterisation of zirconia supported molybdenum oxide and molybdenum carbide catalysts for hydroconversion of n-heptane". Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230933.
The current upgrading catalysts are mainly based on the use of expensive noble metals, which are subject to deactivation due to sintering and coking. An alternative would be to introduce a non-noble metal-based catalyst. In this work, supported molybdenum carbide based systems have been assessed for this purpose. These catalysts were formed by impregnation of zirconia (and zirconium hydroxide) and sulfated zirconia (and zirconium hydroxide) with different loadings of MoO3, with an aim of finding a balance between acid sites and metal-like sites (a site capable of performing dehydrogenation and hydrogenation function without necessarily being a metal). The synthesised catalysts were carburised between 823 and 1123 K using a mixture of methane and hydrogen (4:1) in an attempt to obtain β-Mo2C/ZrO2 or β-Mo2C/S ZrO2. Carburisation at 923 K and above resulted in molybdenum carbide with minimal or no oxygen contents. The conversion and specific rate increased with temperature. Conversion was inversely proportional to space velocity. Analysis of the products distribution as a function of conversion implies that the reaction did not simply follow a consecutive reaction pathway, but that other parallel routes were involved. Conversion increased the research octane number (RON) to ca. 66 due to the increased fraction of pentane isomers. Catalyst carburised at 823 K was approximately four times more active compared to those carburised at 923 K and above, but were of similar activity with Pt/sulfated zirconia. The non-noble metal based catalysts were stable at the reaction temperature while the Pt/sulfated zirconia catalyst deactivates.
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Smith, Marianne R. "The partial oxidation of methane to formaldehyde over molybdenum oxide-based catalysts /". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487780865409586.
Pollard, Ashleigh J. J. "Silica and boron nitride supported molybdenum and vanadium oxide catalysts for alkane oxidation". Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55535/.
A range of silica supported molybdenum catalysts and vanadium catalysts have been prepared and tested for alkane oxidation. Further vanadium catalysts supported on boron nitride have also been prepared and tested for alkane oxidation. The silica supported molybdenum oxide catalysts demonstrated appreciable activity for propane total oxidation to carbon oxides with some trace acrolein. The silica supported vanadium catalysts were also active for propane oxidation, and although the major product was carbon dioxide, higher selectivity to acrolein was observed when compared to the silica supported molybdenum catalysts. The use of boron nitride as a support significantly increased the selectivity towards acrolein and other selective oxidation products like acrylic acid. These results lead to the catalysts being tested for propene oxidation, which produced similar results that showed the boron nitride supported vanadium catalysts were more selective than the silica supported catalysts for acrolein. Further tests were carried out on methane and ethane, which produced mostly carbon oxides as a result. The effect of co-feeding water was also tested when performing propane oxidation with the presence of water effecting the selectivity and activity of the catalysts. Some catalyst's activity was suppressed with increased selectivity to acrolein and other catalysts activity was promoted which led to total oxidation to carbon oxides. This study aim is to compare and contrast the different catalysts produced and give evidence about how the use and development of a hydrophobic support may lead to better catalyst design in the future.
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Dyer, Philip William. "Studies on molecular Oxo and Imido complexes of the group 6 metals and supported chromium oxide polymerisation catalysts". Thesis, Durham University, 1993. http://etheses.dur.ac.uk/5778/.
This thesis describes studies directed towards the preparation of bis (imido) complexes of the Group 6 metals containing olefin, phosphine, acetylene, and alkyl ligands with particular emphasis on their relationship with Group 4 bent metallocenes. The polymerisation mechanism of the Phillips catalyst (CrO(_3)/SiO(_2)) is examined using XPS (X-Ray Photoelectron Spectroscopy) and in situ mass spectroscopy. Chapter 1 highlights properties of some of the important ligand classes that are used throughout the remainder of this thesis. Chapter 2 describes a high yield one-pot synthesis of molybdenum bis (imido) complexes of the type Mo(NR')(NR")Cl(_2).DME. In addition a number of attempts to extend this strategy to other metals are described, including a novel synthesis of the chromium complex [Cr(_2)Cl(_9)] [NHEt(_3)](_3). Chapter 3 describes the synthesis, characterisation, and reactivity of the bis (imido) bis (phosphine) complexes Mo(NAr)(_2)(PMe(_3))(_2) and [Mo(N(^t)Bu)(µ-N(^t)Bu)(PMe(_3))](_2). Further studies on bis (imido) olefin complexes of the type Mo(NAr)(_2)(PMe(_3))2(η(^2)-C(_2)H (_2)) and Mo(N(^t)Bu)(_2)(PMe(_3))(η(^2)-C(_2)H(_4)) was undertaken and concentrated on their structural relationship to Group 4 metallocene species. Chapter 4 describes the preparation, structure, and reactivity of some bis (imido) acetylene complexes Mo(NR)(_2)(PMe(_3)) (PhC=CR’) (R= Ar, (^t)Bu; R'= Ph, H). Preparation of bis (imido) alkyls was undertaken in attempts to generate benzyne and alkylidene derivatives. Chapter 5 studies the Phillips polymerisation catalyst using XPS and mass spectroscopy. Model systems were used to probe reactive surface species their use reveals a number of features that are difficult to observe with the actual catalyst. Aspects of molecular chemistry have been examined which are believed to relate directly to the heterogeneous system allowing a possible polymerisation mechanism to be postulated. Chapter 6 gives experimental details for Chapters 2-5. Philip William Dyer (November 1993)
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Amakawa, Kazuhiko [Verfasser], i Reinhard [Akademischer Betreuer] Schomäcker. "Active Site for Propene Metathesis in Silica-Supported Molybdenum Oxide Catalysts / Kazuhiko Amakawa. Betreuer: Reinhard Schomäcker". Berlin : Technische Universität Berlin, 2013. http://d-nb.info/1067384308/34.
Huffman, David Earl. Studies in molybdenum oxide catalysts: I. Metal vapor reactions of molybdenum trioxide with various alkoxy silanes : II. Investigation of oxide supported molybdenum catalysts prepared from molybdenum(VI)dioxodiethoxide. 1987.
Części książek na temat "Molybdenum oxide catalysts":
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Peri, J. B. "Computerized IR Studies of Cobalt-Molybdenum-Aluminum Oxide Hydrodesulfurization Catalysts". W Catalyst Characterization Science, 422–34. Washington, DC: American Chemical Society, 1985. http://dx.doi.org/10.1021/bk-1985-0288.ch036.
BART, J. C. J., N. GIORDANO i P. FORZATTI. "Phase Relationships in the Cerium-Molybdenum-Tellurium Oxide System". W Solid State Chemistry in Catalysis, 89–101. Washington, D.C.: American Chemical Society, 1985. http://dx.doi.org/10.1021/bk-1985-0279.ch006.
Hall, W. Keith. "Catalysis by Molybdena-Alumina and Related Oxide Systems". W Chemistry and Physics of Solid Surfaces VI, 73–105. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82727-3_5.
Koteru, Bhavish Kumar Reddy, B. Praveen Kumar i Gopalakrishnan Govindasamy. "Synthesis, Characterization and Evaluation of Iron-Molybdenum Oxide Catalyst for the Hydrothermal Liquefaction of Wastewater to Bio-oil". W Springer Proceedings in Earth and Environmental Sciences, 165–73. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-79065-3_13.
Harris, I. M., J. Dwyer, A. A. Garforth, C. H. McAteer i W. J. Ball. "Molybdenum-Oxide-Modified Pentasil Zeolites". W Zeolites as Catalysts, Sorbents and Detergent Builders - Applications and Innovations, Proceedings of an International Symposium, 271–80. Elsevier, 1989. http://dx.doi.org/10.1016/s0167-2991(08)60984-2.
Zazhigalov, Valery O., Olena V. Sachuk, Olena A. Diyuk i Iryna V. Bacherikova. "Mechanochemical and sonochemical syntheses of new nanocomposites". W NEW FUNCTIONAL SUBSTANCES AND MATERIALS FOR CHEMICAL ENGINEERING, 79–92. PH “Akademperiodyka”, 2021. http://dx.doi.org/10.15407/akademperiodyka.444.079.
For the first time the possibility of the complex nanodispersed compound formation at mechanochemical and sonochemical treatment of the initial compounds mixture was shown. Mechochemical treatment of the mixture of molybdenum oxide and bismuth nitrate permits to obtain of bismuth molybdate in form of nanoparticles, in the same time the treatment of mixture of titanium oxide and calcium hydroxide leads to formation of calcium titanate in form of nanoprisms. It was shown that mechanochemical treatment of the mixture of titanium oxide and tin oxide leads to formation of titanium oxide amorphous layer on tin oxide surface. The mechanism of nanodispersed zinc molybdate formation at sonochemical treatment of initial oxides was established. It was shown that nanocomposites synthesized by these methods demonstrate the higher catalytic activity in organic compounds neutralization processes in water solutions at visible light irradiation and in the process of bioethanol selective oxidation to acetaldehyde and hydrogen in comparison with known analogous catalysts synthesized by traditional methods.
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Ito, Y. N., i t. Katsuki. "Oxidation of the C=C bond". W Asymmetric Oxidation Reactions, 19–146. Oxford University PressOxford, 2001. http://dx.doi.org/10.1093/oso/9780198502012.003.0003.
Abstract Metal complexes promote catalytic epoxidation in two different ways: (i) by activation of an oxidant and subsequent migration of an oxygen from the oxidant to olefins; (ii) by oxidation of a metal ion by an oxidant to the high-valent metal oxide and subsequent oxygen transfer to olefins with the reduction of metal ion which can be reoxidized to the metal oxide in situ.The former types of reactions are catalyzed mostly by early transition metal complexes and the latter type of reactions mainly by group VII-X transition metal complexes. For example, t-butyl hydroperoxide is activated by O=V(OR)3 or O2Mo(OR)2 and undergoes epoxidation. During these reactions, the oxidation states of the vanadium and molybdenum ions do not change (Scheme 2.1.1). In general, olefins bearing a precoordinating functional group are good substrates for this type of reaction (see Section 2.3), while epoxidation of isolated olefins is rather slow. On the other hand, stereospecific epoxidation of olefins and C—H hydroxylation of alkanes are realized in living cells with the aid of oxidizing enzymes. Based on the clarification of the catalysis of an iron porphyrin complex at the active site of the representative oxidizing enzyme cytochrome P450, investigations into the enantioselective epoxidation of simple olefins with metalloporphyrin complexes or its equivalents as catalysts were commenced. The P-450-catalysed reactions transfer oxygen atoms to substrates via a high-valent oxo iron porphyrin complex that is produced by the complex redox procedure containing the enzymatic reaction with molecular oxygen. However, the formation of the same oxo species can be chemically effected by treatment of an iron porphyrin complex with stoichiometric oxidants such as iodosylbenzene (Scheme 2.1.2). Besides iron porphyrins, many other metal complexes have been found to catalyse oxygen-transfer reactions via the corresponding high-valent metal oxides.
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Klissurski, D., V. Rives, Y. Pesheva, I. Mitov i R. Stoyanova. "Selective Oxidation of Methanol on Iron-Chromium-Molybdenum Oxide Catalysts". W New Developments in Selective Oxidation II, Proceedings of the Second World Congress and Fourth European Workshop Meeting, 787–94. Elsevier, 1994. http://dx.doi.org/10.1016/s0167-2991(08)63475-8.
Guglielminotti, E., E. Giamello, F. Pinna, G. Strukul, S. Martinengo i L. Zanderighi. "Hydrogenation of Carbon Monoxide Over Rh/ZrO2 Catalysts Promoted by Molybdenum Oxide". W Studies in Surface Science and Catalysis, 2761–64. Elsevier, 1993. http://dx.doi.org/10.1016/s0167-2991(08)64399-2.
Farias, Ana Flávia Felix, Marcos Antonio Gomes Pequeno, Suelen Alves Silva Lucena de Medeiros, Thiago Marinho Duarte, Herbet Bezerra Sales i Ieda Maria Garcia dos Santos. "Zinc oxide or molybdenum oxide deposited on bentonite by the microwave-assisted hydrothermal method: New catalysts for obtaining biodiesel". W Heterogeneous Catalysis, 327–63. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-323-85612-6.00011-5.
Streszczenia konferencji na temat "Molybdenum oxide catalysts":
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Ramaker, David, Daniel Gatewood, Andrew M. Beale i Bert M. Weckhuysen. "ED-XAS Data Reveal In-situ Time-Resolved Adsorbate Coverage on Supported Molybdenum Oxide Catalysts during Propane Dehydrogenation". W X-RAY ABSORPTION FINE STRUCTURE - XAFS13: 13th International Conference. AIP, 2007. http://dx.doi.org/10.1063/1.2644610.
Zhang, D., R. Liang, Q. Ou i S. Zhang. "Fabrication of Amorphous Molybdenum Sulfide/Tungsten Sulfide/Reduced Graphene Oxide Nanocomposites as Efficient Catalysts Toward Hydrogen Evolution Reaction Using Plasma Treatment". W 2022 IEEE International Conference on Plasma Science (ICOPS). IEEE, 2022. http://dx.doi.org/10.1109/icops45751.2022.9813146.
Sokolova, Yulia V. "Recycling of emissions at the complex processing of spent hydrotreatment fuel catalyst". W INTERNATIONAL SCIENTIFIC-TECHNICAL SYMPOSIUM (ISTS) «IMPROVING ENERGY AND RESOURCE-EFFICIENT AND ENVIRONMENTAL SAFETY OF PROCESSES AND DEVICES IN CHEMICAL AND RELATED INDUSTRIES». The Kosygin State University of Russia, 2021. http://dx.doi.org/10.37816/eeste-2021-2-43-46.
An oxidative roasting of industrial spent Co-Mo/Al2O3 catalyst for hydrotreating diesel fuel with lime in an air atmosphere with the capture of sulfur and carbon oxides in the form of gypsum and calcite has been developed. The optimal conditions for the process have been determined. It has been established that the roasting of uncrushed spent catalyst makes it possible, during further processing, to separate molybdenum from aluminum and cobalt oxides by leaching, as well as to obtain lime and send it for roasting.
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Tsakalakos, Loucas, Lauraine Denault, Michael Larsen, Mohamed Rahmane, Yan Gao, Joleyn Balch i Paul Wilson. "Mo2C Nanowires and Ribbons on Si via Two-Step Vapor Phase Growth". W ASME 2004 3rd Integrated Nanosystems Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/nano2004-46098.
Transition metal carbides are an interesting class of electronic materials owing to their high electrical conductivity at room temperature, which is only slightly lower than that of their constituent transition metal elements. For example, the room temperature electrical resistivity of bulk Mo2C is ∼70 μΩ-cm compared to that of Mo (4.85 μΩ-cm), whereas that of NbC is ∼50 μΩ-cm as compared to 15.2 μΩ-cm for Nb. Indeed, the temperature dependent resistivity of many transition metal carbides suggests metallic-like conduction. Furthermore, certain transition metal carbides are known to become superconducting, with transition temperatures ranging from 1.15 °K for TiC1−x to 14 °K for NbC. [1] They are also able to withstand high temperatures and are chemically stable. Initial synthesis of metal carbide nanorods was demonstrated using the carbon nanotube (CNT) confined reaction mechanism by Lieber and co-workers [2] and subsequent superconducting behavior was shown by Fukunaga et al. [3]. Vapor-liquid-solid growth was employed by Johnson et al. [4] to synthesize micron-sized carbide whiskers. Here, we have successfully synthesized Mo2C nanorods and ribbons on Si substrates using a novel two-step catalytic approach, which allows for synthesis of such high temperature nanostructures at manufacturable temperatures (≤ 1000 °C) and time scales (≤ 60 min). In the first step we utilize a catalytic vapor phase process to grow Mo and/or molybdenum oxide nanostructures, which are subsequently carburized in situ to form the desired Mo2C nanostructures. Unlike true VLS growth of carbides, in which high temperature (≤ 1100–1200 °C) is required to adequately dissolve carbon into the catalyst particles, our strategy is to react the nanostructures along their entire length with a carbon vapor source after creating the oxide/metal nanostructures, which for Mo2C can be achieved at relatively low temperatures. (≤ 1000 °C). The nanorods and ribbons are polycrystalline, with a mean grain size of 20–50 nm and 50–150 nm, respectively. We hypothesize that the growth mechanism is a complex mixture of VLS, VSS, and auto-catalytic growth, in which molten catalyst nanoparticles enter a three phase region once the metal precursor is supplied. The growth then presumably continues via a vapor-solid-solid process and is possible assisted by the presence of various molybdenum oxide species on the surface. Initial single nanowire electrical measurements yield a higher resistivity than in the bulk, which is attributed to the fine grain sizes and/or the presence of an oxide layer. A discussion of the growth mechanism will be presented along with issues relating to single nanowire device fabrication and control of nanowire orientation.
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Farooq, Muhammad, Anita Ramli i Duvvuri Subbarao. "Synthesis and characterization of molybdenum catalysts supported on γ-Al[sub 2]O[sub 3]-CeO[sub 2] composite oxides". W INTERNATIONAL CONFERENCE ON FUNDAMENTAL AND APPLIED SCIENCES 2012: (ICFAS2012). AIP, 2012. http://dx.doi.org/10.1063/1.4757539.
