Surface intermediates in selective propylene oxidation and ammoxidation over heterogeneous molybdate and antimonate catalysts

Burrington, James D.; KARTISEK, C. T.; Grasselli, Robert K.

doi:10.1016/0021-9517(84)90197-0

Cited by 157 publications

(29 citation statements)

References 11 publications

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“…However, the present results are inconclusive as to whether the abstraction of the second hydrogen atom occurs before (Adams and Jennings, 1964) or after the insertion of the oxygen atom. In Scheme 1 we subscribe to the latter view, for which there is substantial support (Grasselli and Burrington, 1981;Burrington et al, 1984).…”

Section: Resultsmentioning

confidence: 92%

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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Section: Resultsmentioning

confidence: 92%

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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“…An oxidation mechanism as outlined in Table 3, in which the surface is thought to consist of only antimony and oxygen species. This mechanism is based on a model proposed by Burrington et al (1984) incorporating the involvement of SbdO groups (Carbucicchio et al, 1985). Antimony at the surface can adsorb molecular oxygen yielding a peroxo complex, which decomposes yielding oxygen in the bridging position and an SbdO species.…”

Section: Modeling the Rate Of Formation Of Products On The Basis Of Rmentioning

confidence: 99%

Kinetics of Selective Partial Oxidation of C₃−C₆ α-Olefins over an Iron Antimony Oxide Catalyst

Schnobel

Steen

1997

Ind. Eng. Chem. Res.

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Various models have been tested to describe the influence of carbon number on the kinetics of the selective partial oxidation of R-olefins over iron antimony oxide. Modeling the rate of C 3 -C 6 olefin consumption according to the Mars-van Krevelen redox mechanism showed that the rate constant for the reoxidation was dependent on the carbon number of the used olefin. This and the observed shifts in selectivities cannot be explained in terms of the simplified redox model. The rate of formation of the various product groups was modeled using a power law rate model and mechanistic models on the basis of the single-site Langmuir-Hinshelwood mechanism and on an oxidation mechanism. Using either of the two mechanistic models, one can conclude that the partial oxidation/dehydrogenation products are formed on similar sites, whereas the double-bond isomerization seems to occur on a different site. The kinetic parameters were evaluated as a function of the chain length of the feed molecule.

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“…Researchers have thoroughly studied the mixtures of aforementioned three phases as a single catalyst system to study the synergy effects [2,3]. Most of the authors credit γ phase for the oxygen transport [4,5], whereas α and β phases are credited for their possession of more number of active sites for propylene chemisorption [6,7]. Recently Grunwaldt et al [8] have prepared Bi-Mo oxides by flame pyrolysis with enhanced surface area.…”

Section: Introductionmentioning

confidence: 99%

Partial Oxidation of Propylene over as Prepared and Acid Enriched Bi2Mo1-xWxO6 System

Parab

Naik

Salker

2017

Bull. Chem. React. Eng. Catal.

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The compounds Bi2Mo1-xWxO6 (x = 0.0, 0.2, and 0.4) were obtained through a Citrate sol-gel process. Thermogravimetric differential thermal analysis (TG-DTA), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques were used for characterization. Reitveld refinement of the XRD data confirmed the crystal structure of all the compositions to be orthorhombic, having Pca21 space group. XPS studies indicated the presence of +6 as well as +4 oxidation state for Mo. Surface acid enrichment of all the catalysts was done and monitored by NH3-TPD studies. Partial oxidation of propylene was studied over all the compounds. The W doping was found to increase the catalytic activity. Moreover, as-prepared catalysts and acid enriched catalysts were compared for their catalytic activity wherein, acid-enriched catalysts showed the improved conversion of propylene without hampering the product selectivity profile.

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Surface intermediates in selective propylene oxidation and ammoxidation over heterogeneous molybdate and antimonate catalysts

Cited by 157 publications

References 11 publications

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

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

Kinetics of Selective Partial Oxidation of C₃−C₆ α-Olefins over an Iron Antimony Oxide Catalyst

Partial Oxidation of Propylene over as Prepared and Acid Enriched Bi2Mo1-xWxO6 System

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Surface intermediates in selective propylene oxidation and ammoxidation over heterogeneous molybdate and antimonate catalysts

Cited by 157 publications

References 11 publications

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

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

Kinetics of Selective Partial Oxidation of C3−C6 α-Olefins over an Iron Antimony Oxide Catalyst

Partial Oxidation of Propylene over as Prepared and Acid Enriched Bi2Mo1-xWxO6 System

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Kinetics of Selective Partial Oxidation of C₃−C₆ α-Olefins over an Iron Antimony Oxide Catalyst