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  • 1
    Electronic Resource
    Electronic Resource
    On the reactivity of K2O‐, CaO‐ and P2O5‐doped nickel molybdate catalysts in a periodic‐flow reactor (1999)
    Springer
    Catalysis letters 63 (1999), S. 65-71 
    Details
    ISSN: 1572-879X
    Keywords: propane ODH ; periodic‐flow reactor ; NiMoO4 ; promoters ; acid–base ; reducibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The propane oxydehydrogenation with monolayer lattice oxygen of undoped and K2O–, CaO– and P2O5–NiMoO4 was investigated by using a periodic‐flow reactor (PFR). The influence of the nature and the extent of the promoter has been emphasized relative to the doped catalysts with respect to pure NiMoO4 phases. It was observed that calcium and potassium promoters satisfactorily enhance propylene selectivity, and phosphorus promoter specifically increases the total activity while maintaining the propylene selectivity. Evidence found by thermogravimetric (TG) analyses (oxygen depletion rate) has shown a dependence on lattice oxygen mobility due to the presence of promoters. This dependence has been correlated to the propane conversion while the propylene selectivity was attributed to the acid–base properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019036114414
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  • 2
    Electronic Resource
    Electronic Resource
    Selective propene formation in periodic flow reactor: reducibility and catalytic activity of Ni–Mo–O system (2000)
    Springer
    Catalysis letters 69 (2000), S. 71-78 
    Details
    ISSN: 1572-879X
    Keywords: reducibility ; NiMoO4 lattice oxygen ; propane ODH ; apparent activation energy ; red–ox
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Oxidative dehydrogenation (ODH) of propane with lattice oxygen of α-, α'- and β-NiMoO4 phases has been studied. Reduction tests of the different phases were performed by TG analysis under hydrogen at different temperatures. Under isothermal conditions lattice-oxygen-consumption rate was found to be higher on the β-phase with respect to the α- and α'-phases. TG analyses showed the existence of different sources of lattice oxygen in the catalyst, depending on the NiMoO4 phase. Catalytic activity was measured under steady state conditions, using a periodic flow reactor and it was then correlated to the reduction curve. It was found that the activation energy for ODH reaction over NiMoO4 of 54.3–62.7 kJ/mol is nearly identical to that obtained for the catalyst reduction under hydrogen (46–50.2 kJ/mol). The correlation between the activation energy of the reaction in a periodic operating system (POS) and that of solid reduction under hydrogen suggests that the reaction obeys a red–ox mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019045201036
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  • 3
    Electronic Resource
    Electronic Resource
    Deactivation of alkane oxidative dehydrogenation catalyst by deep reduction in periodic flow reactor (1998)
    Springer
    Catalysis letters 55 (1998), S. 93-95 
    Details
    ISSN: 1572-879X
    Keywords: propane oxidative dehydrogenation ; catalyst deactivation ; periodic flow reactor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The activity loss of β‐NiMoO4 catalyst has been studied in the oxidative dehydrogenation of propane with an operating periodic flow reactor. Under severe operating conditions (i.e., high temperature and long periods of the pulses), the lattice oxygen depletion is faster than the reoxidation one. After an induction period, carbon whiskers on the catalyst surface were detected together with noticeable amounts of cracking products in the gas phase as CH4, C2 hydrocarbons and H2. Deep reduction dramatically changes the reaction path and irreversibly modifies the catalyst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1019058223307
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  • 4
    Electronic Resource
    Electronic Resource
    Carbon deposition in methane reforming with carbon dioxide (1996)
    Springer
    Journal of thermal analysis and calorimetry 47 (1996), S. 227-234 
    Details
    ISSN: 1572-8943
    Keywords: carbon deposition ; dry reforming ; Ni catalysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Coke formation in the dry reforming of methane was studied using a thermobalance (TG) and with a catalytic microreactor in the temperature range 800–950 K. Silica-supported and lanthana-supported nickel catalysts were examined. The effects of process variables such as temperature and gas composition (He dilution, CH4/CO2 ratio) on the coke formation rate were determined. The reactivity of H2 on several kinds of carbon was also investigated. The morphology of the coke was studied by scanning electron microscopy (SEM). The induction times for coke formation were significantly affected by temperature and by the CO content in the feed gas. The results of catalytic tests were consistent with the TG measurements. The behaviour of SiO2 and La2O3 supported Ni catalysts agree with a mechanism in which the lanthana support plays an important role in the carbon deposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01982701
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  • 5
    Electronic Resource
    Electronic Resource
    On the Preparation of Ni–La Supported on Silica by Sol-gel Process via Propionates (2000)
    Springer
    Journal of thermal analysis and calorimetry 62 (2000), S. 609-619 
    Details
    ISSN: 1572-8943
    Keywords: Ni–La–Si–O system ; methane dry reforming ; sol-gel preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ni–La/SiO2 catalysts were prepared by using a new metal organic precursor M(OC3H7)n, dissolved in organic solvent, hydrolysed and finally condensed to form inorganic polymers containing M–O–M or M–(µOH)–M linkages. An optimal distribution of both the active phase ‘Ni’ and the promoter ‘La2O3’ was ensured by addition of their corresponding salts, previously dissolved in propionic acid, to a silica solution prior to gelation. After drying under vacuum the precursor was submitted to thermal treatment in air at 600°C with a heating rate of 1°C min–1. The precursors and the corresponding catalysts were characterised by various techniques (TG-DTA, XRD, FTIR, TEM, BET and porosimetry) and tested for methane dry reforming.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1012004921118
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  • 6
    Electronic Resource
    Electronic Resource
    Oxidation of isobutene over cuprous oxide between 400 and 550°C (1978)
    Springer
    Reaction kinetics and catalysis letters 9 (1978), S. 23-27 
    Details
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Было найдено, что в исследованном интервале температур выход продуктов мягкого окисления сильно зависит от парциального давления кислорода. п-Аллильные промежуточные продукты претерпевают окисление до метакролеина или димеризуются до 2,5-диметил-1,5-гексадиена и после циклоароматизации образуется п-ксилол.
    Notes: Abstract In the temperature range investigated the mild oxidation products are strongly affected by the oxygen partial pressure. The π-allyl intermediates may undergo oxidation to methocrolein or dimerization to 2,5-dimethyl-1,5-hexadiene and after cycloaromatization to p-xylene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02070363
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  • 7
    Electronic Resource
    Electronic Resource
    Aging and activation of α-NiMoO4 catalyst for selective propane oxydehydrogenation into propene (1999)
    Springer
    Reaction kinetics and catalysis letters 68 (1999), S. 175-181 
    Details
    ISSN: 1588-2837
    Keywords: Aging ; polymorphic nickel molybdate ; propane activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Increase in catalytic activity performance of a stoichiometric NiMoO4 system has been studied using a periodic flow reactor system. Aging results in an increase of selectivity, a decrease in BET surface area, a weak decrease in activity and a change in surface morphological properties. α-Nickel molybdate exposed to the reaction gases and temperature tends to transform progressively toward an α-aged phase more and more like to the most selective β-phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02475499
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  • 8
    Electronic Resource
    Electronic Resource
    Use of ozonized oxygen in heterogeneous catalysis. Effect on the apparent activation energy (1976)
    Springer
    Reaction kinetics and catalysis letters 5 (1976), S. 245-249 
    Details
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Исследовано каталитическое низших олефинов. Изучен эффект кислорода, содержащего озон. Результаты указывают на понижение кажущейся энергии активации. Описанное рвление имеет промышленное значение.
    Notes: Abstract The catalytic oxidation of lower olefins has been studied. The effect of ozonized oxygen has been examined. The results show that the apparent activation energy decreases. The industrial importance of the phenomenon is pointed out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02063032
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  • 9
    Electronic Resource
    Electronic Resource
    Polymerization of propylene to syndiotactic polymer. Part. I: Valence of active vanadium in the catalytic systems (1965)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 81 (1965), S. 161-172 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: An homogenen Katalysatorsystemen für die Polymerisation von Propylen zu syndiotaktischen oder amorphen Polymeren, hergestellt aus lölichen Vanadium-Salzen und metallorganischen Verbindungen des Aluminiums, wurden bei verschiedenen Temperaturen EPR-Untersuchungen durchgeführt. Es wurde geschlossen, daß das Vanadium in diesen Katalysatorkomplexen im 3-wertigen Zustand vorliegt.
    Notes: Homogeneous catalytic systems for the polymerization of propylene both to syndiotactic and amorphous polymers, based on soluble vanadium compounds and organometallic compounds of aluminium, were investigated by EPR analysis at different temperatures. It was shown that the vanadium in the catalytic complex has a valence state of 3.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1965.020810118
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