Redox Properties of VPO Ammoxidation Catalysts

Martin, Andreas; Lücke, Bernhard

doi:10.1002/(sici)1521-4125(199904)22:4<294::aid-ceat294>3.0.co;2-9

Cited by 3 publications

(3 citation statements)

References 10 publications

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“…Ammoxidations of substituted methyl aromatics and methylheteroaromatics have been performed with success in reactions catalyzed by vanadium phosphate materials (88)(89)(90)270,(284)(285)(286)(287)(288)(289)(290)(291)(292)(293). However, the ammoxidation catalysts commonly have higher phosphorus contents than the (VO) 2 P 2 O 7 (V:P ¼ 1:1) that is routinely used for oxidation, and they may have different vanadium oxidation states and are often supported.…”

Section: Ammoxidationmentioning

confidence: 99%

Vanadium Phosphate Materials as Selective Oxidation Catalysts

Dummer

Bartley

2011

Advances in Catalysis

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Section: Ammoxidationmentioning

confidence: 99%

Vanadium Phosphate Materials as Selective Oxidation Catalysts

Dummer

Bartley

2011

Advances in Catalysis

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“…Efficient and highly active catalysts for aldol condensations are the key for future research. Two kinds of catalysts were tested for the target reaction, including base and acid catalysts such as phosphates , . Alkali metal oxides or alkaline earth metal oxides supported catalysts were usually applied as base catalysts.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Catalytic Activity with Oxygen for Methyl Acrylate Production via Cross‐Aldol Condensation Reaction

Zuo

Wang

et al. 2018

Chem Eng & Technol

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An innovative technology for the production of methyl acrylate via vapor-phase cross-aldol condensation is described. Catalytic process intensification was realized through the enhanced catalytic activity with oxygen by catalyst design and adjustment of active sites. Crystal phases with different V valences in vanadium phosphate catalysts were controllably synthesized in the presence of oxygen. Donating electron and withdrawing electron sites arose when oxygen moved from one crystalline phase to another, just for the a-H removal of methyl acetate and formaldehyde protonation. The reaction pathway and transition states were confirmed via molecular simulation with quantum chemistry theory. The catalytic activity was evaluated in a fixed-bed reactor by adjusting the percentage of oxygen in the carrier gas. Finally, the mechanism of a-H removal of methyl acetate through the activated oxygen was clarified.

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“…1 summarizes known transformations of VPO phases under different environments, which are typically dominated by V 4+ and V 5+ phases, however, the presence of V 3+ phase is reported in the literature. 6,7 Alas the specific phases containing such phases have not been identified yet.…”

Section: Introductionmentioning

confidence: 99%

Operando and in situ Raman studies of alumina-supported vanadium phosphatecatalysts in propane ammoxidation reaction: activity, selectivity and active phase formation

Mikolajska

Rasmussen

Lewandowska

et al. 2012

Phys. Chem. Chem. Phys.

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Alumina-supported VPO materials are efficient catalysts for acrylonitrile production by the propane ammoxidation reaction. In order to understand the structure-activity relationship and the nature of active sites, operando Raman-GC analyses follow the states of vanadium and phosphorous species on an alumina support during ammoxidation. These oxides were supported on γ-alumina by incipient wetness impregnation at a total V + P loading of two monolayers, which led to incipient formation of nanoscaled VPO crystallites possessing a high surface-to-volume ratio. Since catalysis occurs at the catalyst surface, which is related to the surface and outermost layers, this approach allows studying surface species phase transformations near the surface, and relates changes in activity and selectivity to variations in composition and structure. Dispersed surface V(5+) species appear selective to acetonitrile and V(4+) species would promote selectivity to acrylonitrile. This study suggests that V(3+) is probably involved in redox processes during propane ammoxidation and that the balance between these vanadium species would be determined by activation process.

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Redox Properties of VPO Ammoxidation Catalysts

Cited by 3 publications

References 10 publications

Vanadium Phosphate Materials as Selective Oxidation Catalysts

Vanadium Phosphate Materials as Selective Oxidation Catalysts

Enhanced Catalytic Activity with Oxygen for Methyl Acrylate Production via Cross‐Aldol Condensation Reaction

Operando and in situ Raman studies of alumina-supported vanadium phosphatecatalysts in propane ammoxidation reaction: activity, selectivity and active phase formation

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