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Propane ammoxidation on an Al-Sb-V-W-oxide catalyst. A mechanistic study using the TAP-2 reactor system

Hinz, A and Andersson, Arne LU (1999) In Chemical Engineering Science 54(20). p.4407-4421
Abstract
The reaction mechanism of propane ammoxidation was studied on an Al-Sb-V-W-oxide catalyst using a TAP-2 reactor system. Analyses of the responses from both high-speed pulse transients with reactants and TPD experiments were performed. Since the ammoxidation process with three reactants proceeds from propane to acrylonitrile over propylene as an intermediate, the experiments comprised oxidation of propylene, oxidation of ammonia, ammoxidation of propylene, oxidation of propane, and ammoxidation of propane. The results show that propane is irreversibly adsorbed at the surface forming propylene, which desorbs. Propylene then readsorbs forming an intermediate allyl species, which reacts with lattice oxygen to give acrolein. Acrolein is... (More)
The reaction mechanism of propane ammoxidation was studied on an Al-Sb-V-W-oxide catalyst using a TAP-2 reactor system. Analyses of the responses from both high-speed pulse transients with reactants and TPD experiments were performed. Since the ammoxidation process with three reactants proceeds from propane to acrylonitrile over propylene as an intermediate, the experiments comprised oxidation of propylene, oxidation of ammonia, ammoxidation of propylene, oxidation of propane, and ammoxidation of propane. The results show that propane is irreversibly adsorbed at the surface forming propylene, which desorbs. Propylene then readsorbs forming an intermediate allyl species, which reacts with lattice oxygen to give acrolein. Acrolein is unstable and some of it reacts further to produce either carbon oxides, or, acrylonitrile. Formation of the nitrile occurs by adsorbed acrolein reacting with an NH, species. The latter species is short-lived and reacts competitively to form N-2, N2O and NO. Lattice oxygen plays an important role in the pathway to acrylonitrile. However, weakly adsorbed oxygen species are also present at the catalyst surface, and these species participate in degradation routes producing waste products. Consideration of the mechanistic scheme which is derived from the experimental results shows the possibility to achieve improvement of the ammoxidation process by using either a recirculating solids reactor, or a high propane/oxygen ratio in the feed. (C) 1999 Elsevier Science Ltd. All rights reserved. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
propane ammoxidation, Al-Sb-V-W-oxide, reaction mechanism, transient, study, TAP-2 reactor system
in
Chemical Engineering Science
volume
54
issue
20
pages
4407 - 4421
publisher
Elsevier
external identifiers
  • wos:000081864700015
  • scopus:0032701355
ISSN
0009-2509
DOI
10.1016/S0009-2509(99)00138-4
language
English
LU publication?
yes
id
f8beb4b5-8062-471f-8174-7aecb091b113 (old id 3915203)
date added to LUP
2013-07-02 08:21:41
date last changed
2017-04-30 13:18:56
@article{f8beb4b5-8062-471f-8174-7aecb091b113,
  abstract     = {The reaction mechanism of propane ammoxidation was studied on an Al-Sb-V-W-oxide catalyst using a TAP-2 reactor system. Analyses of the responses from both high-speed pulse transients with reactants and TPD experiments were performed. Since the ammoxidation process with three reactants proceeds from propane to acrylonitrile over propylene as an intermediate, the experiments comprised oxidation of propylene, oxidation of ammonia, ammoxidation of propylene, oxidation of propane, and ammoxidation of propane. The results show that propane is irreversibly adsorbed at the surface forming propylene, which desorbs. Propylene then readsorbs forming an intermediate allyl species, which reacts with lattice oxygen to give acrolein. Acrolein is unstable and some of it reacts further to produce either carbon oxides, or, acrylonitrile. Formation of the nitrile occurs by adsorbed acrolein reacting with an NH, species. The latter species is short-lived and reacts competitively to form N-2, N2O and NO. Lattice oxygen plays an important role in the pathway to acrylonitrile. However, weakly adsorbed oxygen species are also present at the catalyst surface, and these species participate in degradation routes producing waste products. Consideration of the mechanistic scheme which is derived from the experimental results shows the possibility to achieve improvement of the ammoxidation process by using either a recirculating solids reactor, or a high propane/oxygen ratio in the feed. (C) 1999 Elsevier Science Ltd. All rights reserved.},
  author       = {Hinz, A and Andersson, Arne},
  issn         = {0009-2509},
  keyword      = {propane ammoxidation,Al-Sb-V-W-oxide,reaction mechanism,transient,study,TAP-2 reactor system},
  language     = {eng},
  number       = {20},
  pages        = {4407--4421},
  publisher    = {Elsevier},
  series       = {Chemical Engineering Science},
  title        = {Propane ammoxidation on an Al-Sb-V-W-oxide catalyst. A mechanistic study using the TAP-2 reactor system},
  url          = {http://dx.doi.org/10.1016/S0009-2509(99)00138-4},
  volume       = {54},
  year         = {1999},
}