Kinetic Isotope Effect in the Ammoxidation of Propane over an Alumina Supported Vanadium Antimony Oxide Catalyst

Brazdil, Linda C.; Ebner, Ann M.; Brazdil, James F.

doi:10.1006/jcat.1996.0310

Cited by 20 publications

(6 citation statements)

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“…On the contrary, ammonia can adsorb on the V site of the rutile whereas propane can adsorb on the V site of the dispersed vanadium oxide phase, since the adsorption of propane is preferentially favored on these sites. This has previously been demonstrated since adsorbed alkoxide species on VOx sites were identified by operando Raman ( 41 ) and deuterium isotopic exchange demonstrates that propane activation occurs at its intermediate methylene carbon ( 42 ). Thus, the reaction was carried out in the opposite way and pure propane pulses were introduced into a 50 ml/min ammonia/oxygen flow with results shown in Figure 5.…”

Section: Oxidation Of Propane Over V/al Catalystsupporting

confidence: 53%

Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

Guerrero‐Pérez

McCue

Anderson

2020

Journal of Catalysis

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Rapid scan FTIR coupled with Mass Spectrometry (MS) has been used to determine the role of spectroscopically observed species in the reaction media during propane dehydrogenation over a V/Al catalyst, and propane ammoxidation on a Sb-V-O sample. During the propane dehydrogenation reaction, it was shown that oxygenates are not formed during the first minutes and propylene is formed directly from propane via dehydrogenation on a V-O site. Oxygenates may form though secondary reactions due to further propylene oxidation. Propane dehydrogenation is the first step during the propane ammoxidation reaction. This is followed by the transformation of propylene into acrylonitrile, which is the rate limiting step. Rapid scan FTIR/MS is shown to be a useful technique for monitoring chemical reactions in order to identify or eliminate observed surface species as potential reaction intermediates. Understanding of the reaction mechanism is necessary in order to improve the chemical process design and the catalytic material.

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Section: Oxidation Of Propane Over V/al Catalystsupporting

confidence: 53%

Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

Guerrero‐Pérez

McCue

Anderson

2020

Journal of Catalysis

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“…In a recent study using deuterated propanes (Brazdil et al, 1996), a kinetic isotope effect for propane ammoxidation over a promoted Sb-V-O catalyst was Figure 9. Experimental responses of (a) propane, ammonia, and oxygen, (b) propene, acrylonitrile, and acrolein, and (c) carbon monoxide + nitrogen, carbon dioxide + nitrous oxide, and water, after a step change from argon to argon containing 2500 ppm of propane, 2500 ppm of ammonia, and 5000 ppm of oxygen.…”

Section: Resultsmentioning

confidence: 96%

“…In a recent study using deuterated propanes (Brazdil et al, 1996), a kinetic isotope effect for propane ammoxidation over a promoted Sb-V-O catalyst was observed. The authors limited their rate analysis to the consumption of propane, since a rate analysis of the products was impossible due to the scrambling of hydrogen and deuterium in the formed acrylonitrile.…”

Section: Resultsmentioning

confidence: 96%

Transient Response Study of the Ammoxidation of Propene and Propane on an Sb−V−Oxide Catalyst

Nilsson

Andersson

1997

Ind. Eng. Chem. Res.

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The reaction pathways in the ammoxidation of propene and of propane over an Sb-V-oxide catalyst were studied by analyzing the modes of transient responses of reactants and products resulting from step changes from inert gas to reactant feed. The pathway from propane to acrylonitrile begins with the oxidative dehydrogenation of propane to form propene. After readsorption, the propene is then transformed into adsorbed acrolein, which eventually reacts with an NH x surface species to form acrylonitrile. The adsorption of propane is rate limiting for the propane conversion, but the desorption of water formed from the propene is slow and determines the product distribution. The response modes for the direct oxidation and ammoxidation of propene are consistent with the desorption of water being rate limiting. A comparison of the experimental responses with responses simulated under the assumption that the formation of an allylic intermediate is rate determining reveals an important difference in profiles, indicating this step to not be rate determining. The results show that substantial qualitative information concerning the reaction pathways can be obtained from the analysis of transient profile modes.

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“…However, ammonia adsorbs much more strongly on these sites. , Therefore, during propane ammoxidation competitive adsorption of NH 3 would prevent propane adsorption on the trirutile vanadium sites. However, Raman spectra during ammoxidation evidence the presence of adsorbed alkoxide species, , and deuterium isotopic exchange demonstrates that propane activation occurs at its intermediate methylene carbon site . This fact would explain the need of dispersed vanadium oxide species in the Sb–V–O catalysts for propane ammoxidation since such species have been identified on the surface of the Sb–V–O catalysts by Raman spectroscopy. ,, Furthermore, stoichiometric vanadium antimonate hardly converts propane to acrylonitrile, and operando Raman-GC spectra show that there are almost no visible vanadium alkoxide species.…”

Section: Resultsmentioning

confidence: 99%

Theoretical and Experimental Study of Light Hydrocarbon Ammoxidation and Oxidative Dehydrogenation on (110)-VSbO₄ Surfaces

et al. 2012

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Density Functional Theory (DFT) calculations have been performed for ethane, ethylene, propane, and propylene adsorption on the rutile VSbO4 structure to uncover the reaction mechanism during both ODH and ammoxidation reactions. This study is complementary to a previous paper in which the adsorption of ammonia on this structure was deeply analyzed, and in addition, experimental activity results for both reactions are shown to complete the theoretical DFT calculations. These results show that ammonia, ethane, and ethylene compete for the same active sites, the former adsorbing strongly. This explains why this catalytic system is not active for ethane ammoxidation; the presence of ammonia blocks the other molecule adsorption sites and prevents ethane oxidative dehydrogenation to ethylene. Such competition does not occur with propane or propene since the adsorption of both ammonia and hydrocarbon is possible at different sites, explaining why this catalytic system is active for propane ODH reaction. During ammoxidation, molecularly dispersed VOx species are able to transform the propane molecule into propylene. Then, intermediate propylene can coadsorb along with ammonia on the trirutile VSbO4, inserting the nitrogen atom that forms acrylonitrile. Calculations show that the adsorptions studied are more favored when the rutile structure presents a cationic vacancy.

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Kinetic Isotope Effect in the Ammoxidation of Propane over an Alumina Supported Vanadium Antimony Oxide Catalyst

Cited by 20 publications

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Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

Transient Response Study of the Ammoxidation of Propene and Propane on an Sb−V−Oxide Catalyst

Theoretical and Experimental Study of Light Hydrocarbon Ammoxidation and Oxidative Dehydrogenation on (110)-VSbO₄ Surfaces

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Kinetic Isotope Effect in the Ammoxidation of Propane over an Alumina Supported Vanadium Antimony Oxide Catalyst

Cited by 20 publications

References 0 publications

Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

Transient Response Study of the Ammoxidation of Propene and Propane on an Sb−V−Oxide Catalyst

Theoretical and Experimental Study of Light Hydrocarbon Ammoxidation and Oxidative Dehydrogenation on (110)-VSbO4 Surfaces

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Theoretical and Experimental Study of Light Hydrocarbon Ammoxidation and Oxidative Dehydrogenation on (110)-VSbO₄ Surfaces