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1
Selective Oxidation of Isobutane and Isobutene over Hydrothermally Synthesized Mo-V-Te-Ce–O Mixed Oxide Catalyst
Guan J. Q., Wu S. J., Shao Y. Q., Ma Y. Y., Shang F. P., Yu X. F., Liu J., Kan Q. B.
Polish Journal of Chemistry
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2009
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Vol. 83, nr 4
605-613
EN
MoV0.3Te0.23 and MoV0.3Te0.23Ce0.2 catalysts were prepared by a hydrothermal synthesis method and tested for the oxidation of isobutane and isobutene. Characterization results (XRD, FT-IR, TPR, BET, and XPS) showed that the structure and properties of the Mo–V–Te-based catalysts are relatively different depending on the presence of Ce element. Catalytic tests showed that the selectivity to methacrylic acid can comparatively be improved by the addition of Ce into the MoV0.3Te0.23 catalyst for the selective oxidation of isobutane.
2
Preparation of Mo-V Catalysts for Selective Oxidation of Isobutane
Guan J. Q., Wu S. J., Jing S. B., Xu C., Wang Z. Q., Shang F. P., Kan Q. B.
Polish Journal of Chemistry
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2009
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Vol. 83, nr 10
1831-1836
EN
A series of Mo-V-O catalysts for the selective oxidation of isobutane were prepared by a hydrothermal method and by a solution reaction. The synthesis method, catalyst composition and calcination temperature have great effect on the catalytic behavior. Catalytic tests showed that MoV0.3 catalyst prepared by a hydrothermal method exhibited the best catalytic behavior. Using this catalyst 10.7 per cent selectivity to methacrolein and 15.3 per cent selectivity to methacrylic acid can be achieved at an isobutane conversion of 10.4 per cent at 380 graduate C.
3
Vanadium-containing Mesoporous Molecular Sieves: Synthesis, Properties and Catalytic Performance in Oxidative Activation of Light Alkanes
Cortés Corberán V., Sulikowski B.
Polish Journal of Chemistry
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2008
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Vol. 82, nr 9
1823-1837
EN
Vanadium-containing mesoporous molecular sieves (MMS) are quasi-crystalline solids with interesting catalytic properties in the oxidative activation of light alkanes. In the present work, the methods of their synthesis, physico-chemical properties and catalytic behaviour in the oxidative dehydrogenation and selective oxidation of C2-C4 alkanes are reviewed. It is concluded that, as with conventional supported vanadium contacts, the catalytic performance in these reactions is related to the number and environment of vanadium centres, and the best selectivity and yield are obtained over isolated vanadium sites exhibiting tetrahedral coordination.
4
Selective Oxidation of Isobutane and Isobutene over Mo-Te Mixed Oxide Catalysts
Guan J. Q., Wu J. S., Shao Y. Q., Xu H. Y., Yang Y., Xu L., Zhen K. J., Kan Q. B.
Polish Journal of Chemistry
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2008
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Vol. 82, nr 8
1571-1571
EN
A series of TeMox (x = 3–6) mixed oxides were prepared and investigated for the selective oxidation of isobutane and isobutene. Both the characterization results and the catalytic properties of the samples are quite different, depending on the composition of the calcined samples. Among them, TeMo3 catalyst showed the best total selectivity to methacrolein and methacrylic acid (as high as 46%), and their yield reached 10.1% at 400°C in the selective oxidation of isobutane. How ever, TeMo4 catalyst showed the best catalytic performance in the selective oxidation of isobutene, in which 73% selectivity to methacrolein and 9% selectivity to methacrylic acid can be obtained at 77.5% isobutene conversion at 440 graduate C.
5
Content available remote CADiff - the inter and reactive diffusion simulation tool
Wierzba B., Pietrzyk M., Danielewski M.
Computer Methods in Materials Science
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2008
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Vol. 8, No. 1
47-53
EN
The CADiff software is presented in the paper. The method based on the extended Darken and Wagner models, allows to simulate the inter and reactive diffusion processes. The diffusion fluxes are defined in the volume fixed reference frame. The Darken method is extended to include the non ideal alloys showing different partial molar volumes and boundary conditions taking into account both the diffusion and the surface reactions. The CADiff simulation tool allow to compute a wide range of interdiffusion processes starting from the Fick constitutive diffusion flux formula to the combined Darken-Onsager approach. They allow to model pure interdiffusion in multi-component systems as well as a wide class of the reaction-diffusion problems associated with solid state chemistry, corrosion, surface treatment etc.
PL
W artykule zaprezentowana została metoda (model) oraz oprogramowanie CADiff. Metoda ta opiera się na uogólnionej metodzie Darkena dla układów wieloskładnikowych oraz modelu Wagnera. Pozwala ona na symulowanie zjawisk dyfuzji wzajemnej i reakcyjnej. Strumienie dyfuzyjne zdefiniowane zostały w objętościowym układzie odniesienia. Metoda Darkena rozwinięta została do symulowania zjawiska dyfuzji w układach otwartych uwzględniając różne objętości molowe składników. Metoda oraz oprogramowanie CADiff umożliwia symulowanie zjawiska dyfuzji wzajemnej z wykorzystaniem wielu matematycznych opisów, między innymi: prawa Ficka, metoda Onsagera, połączone metody Onsagera i Darkena oraz uogólnionej metody Darkena. Umożliwia ona na symulowanie zarówno samego zjawiska dyfuzji wzajemnej (w układach zamkniętych) jak również zjawisk dyfuzji wzajemnej połączonych z reakcjami na granic.
6
Content available remote Kinetic model for selective oxidation of o-xylene to phthalic anhydride in terms of catalyst deactivation
Krajewski W., Najzarek Z.
Chemical and Process Engineering
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2007
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Vol. 28, z. 4
899-908
EN
he process of selective oxidation of o-xylene in a tubular reactor over a vanadia-titania catalyst (V2O5/TiO2) with the catalyst thermal deactivation have been described by means of the Langmuir-Hinshelwood kinetics, while the Erofeev equation for the catalyst deactivation was adopted. On the basis of the model, the kinetic constants have been calculated for eight oxidation reactions from the substrate to the products. Moreover, the catalyst deactivation constants have been determined. The calculation results predict correctly measurements data for the process in the tubular reactor.
PL
Model procesu selektywnego utleniania o-ksylenu w reaktorze rurowym na katalizatorze wanadowo-tytanowym (V2O5/TiO2) z uwzględnieniem termicznej dezaktywacji katalizatora opisano kinetyką Langmuira-Hinshelwooda, a dezaktywację katalizatora wanadowo-tytanowego równaniami Jierofiejewa. Obliczono stałe kinetyczne dla ośmiu reakcji utlenienia od substratu do produktów oraz wyznaczono stałe dezaktywacji katalizatora. Wyniki obliczeń są zgodne z wynikami pomiarów dla procesu w reaktorze rurowym.
7
Selective Oxidation and Oxidative Dehydrogenation of Isobutane on Mo-V-Te-P Mixed Metal Oxide Catalysts
Guan J., Wang G., Jing S., Wang Z., Kan Q.
Polish Journal of Chemistry
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2006
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Vol. 80, nr 8
1397-1405
EN
MoV0.3Te0.23Px (x = 0-0.5) catalysts have been prepared and tested in the selective oxidation of isobutane. Among them, MoV0.3Te0.23P0.3 catalyses the direct oxidation of isobutane to methacrolein and methacrylic acid with 33% selectivity, and a total dehydrogenation (olefin plus methacrolein andmethacrylic acid) selectivity up to 63%at 400 graduate C.
8
Hydrogen Peroxide Oxidation of Mono- and Disubstituted Alkylarenes Catalyzed by Dinuclear CoIII-CuII Macrocyclic Complex
Golchoubian H., Ghaziani A.
Polish Journal of Chemistry
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2005
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Vol. 79 / nr 5
825-830
EN
C-H oxidation of anthracene and eight other alkylarenes with binuclear macrocyclic complex of CoIII-CuII as a catalyst in the presence of 30% aqueous hydrogen peroxide to the corresponding carbonyl compounds were studied. The oxidation took place selectively at the benzylic C-H bond and no oxidation was observed in aromatic ring. The reaction is simple, clean and high yielding and generates water as the only by-product.
9
Selective oxidation of Fe-Ni-Cr alloys.
Danielewski M., Filipek R., Milewska A.
Inżynieria Materiałowa
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2001
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R. XXII, nr 4
278-280
PL
W oparciu o model utleniania stopów dwuskładnikowych typu Ni-Pt, Wagnera oraz uogólnioną metodę dyfuzji wzajemnej Darkena (GDM) przeprowadziliśmy symulacje selektywnego utleniania stopów wieloskładnikowych. Uzyskane rozwiązanie pozwala badać ewolucje rozkładów koncentracji składników w układach zamkniętych i otwartych dla dowolnych warunków początkowych i brzegowych. Wykazaliśmy przydatność prezentowanej metody w obliczaniu zmian koncentracji składników przy powierzchni stopIzgorzelina (które są efektem reakcji na powierzchni stopu). Wykonane symulacje dyfuzji wzajemnej w selektywnie utlenianym stopie (Fe-48 Cr) i selektywnie siarkowanym stopie trójskładnikowym (Fe-18Cr-9Ni w % wag.) wykazują zadowalającą ilościową zgodność z wynikami eksperymentalnymi.
EN
The Wagner model of oxidation of binary Ni-Pt type alloys and the Generalized Darken Method of Interdiffusion (GDM) are combined to describe the selective oxidation of multicomponent alloys. The solution of the GDM enables one to obtain an exact expression for the evolution of component distributions in closed and open systems, for arbitrary initial distributions and time dependent boundary conditions. We show the usefulness of the presented method in estimating the changes of density of elements at the alloyIscale interface (a result of reaction at the interface). The simulations of the interdiffusion in selectively oxidized binary (Fe-48Cr) and selectively sulphidized ternary (Fe-18Cr-9Ni in wt.%) alloys show the qualitative agreement with the experimental results.
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