Advanced

An investigation of the Al-Sb-V-W-oxide system for propane ammoxidation

Nilsson, J; Landa-Canovas, AR; Hansen, Staffan LU and Andersson, Arne LU (1999) In Journal of Catalysis 186(2). p.442-457
Abstract
AlSb-V-W-oxide catalysts were prepared and used for propane ammoxidation to give acrylonitrile. The preparations were characterized, both as freshly prepared and after use in propane ammoxidation, using XRD, XPS, Raman spectroscopy, and transmission electron microscopy together with electron diffraction and X-ray microanalysis. Activity tests of the freshly prepared samples reveal a remarkable activation behaviour with time-on-stream under influence from the reaction medium. During the first 15-50 h on-stream, a considerable increase in the activity and the selectivity to acrylonitrile is observed in parallel with a decrease in the selectivity to waste products. The duration of the activation period depends on the W-content and increases... (More)
AlSb-V-W-oxide catalysts were prepared and used for propane ammoxidation to give acrylonitrile. The preparations were characterized, both as freshly prepared and after use in propane ammoxidation, using XRD, XPS, Raman spectroscopy, and transmission electron microscopy together with electron diffraction and X-ray microanalysis. Activity tests of the freshly prepared samples reveal a remarkable activation behaviour with time-on-stream under influence from the reaction medium. During the first 15-50 h on-stream, a considerable increase in the activity and the selectivity to acrylonitrile is observed in parallel with a decrease in the selectivity to waste products. The duration of the activation period depends on the W-content and increases with increase of the latter. Characterization with TEM, electron diffraction, and X-ray microanalysis show that the activation of the catalyst precursor under reaction conditions results in the formation of an approximate to Sb(V, W)O-4 phase of rutile-type, which is active and selective to acrylonitrile formation. The aluminum in the catalysts is present in form of delta-Al2O3, which serves as a catalyst support. Analysis of the catalysts and their precursors with XPS shows coverage of the alumina surface with oxides with Sb, V, and W, and the Raman spectra show the presence of tetrahedral and octahedral tungsten oxide species being attached to the alumina surface. Both XPS and X-ray microanalysis results indicate that the surfaces and the external layers of the precursors are enriched with antimony. Activity test of an Al-Sb-V-W-oxide catalyst with Sb:V:W = 5 : 1:2 and 50 wt% Al2O3, using a feed which is stoichiometric with respect to acrylonitrile formation, shows that the selectivity to acrylonitrile is 48% at 77% propane conversion, corresponding to a yield of 37%. Comparison with Sb-V-oxide and Al-Sb-V-oxide preparations reveals a substantial improvement of the catalytic properties with the addition of Al and W to Sb-V-oxide. (C) 1999 Academic Press. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
propane, ammoxidation, acrylonitrile formation, Al-Sb-V-oxide catalysts, catalyst characterization, XRD, XPS, Raman spectroscopy, transmission, electron microscopy, electron diffraction, X-ray microanalysis
in
Journal of Catalysis
volume
186
issue
2
pages
442 - 457
publisher
Elsevier
external identifiers
  • wos:000082789800020
  • scopus:0000002377
ISSN
1090-2694
DOI
10.1006/jcat.1999.2570
language
English
LU publication?
yes
id
ce81f592-7c19-44a3-93d3-558a1fc88409 (old id 3915207)
date added to LUP
2013-07-02 08:23:44
date last changed
2017-04-30 07:38:07
@article{ce81f592-7c19-44a3-93d3-558a1fc88409,
  abstract     = {AlSb-V-W-oxide catalysts were prepared and used for propane ammoxidation to give acrylonitrile. The preparations were characterized, both as freshly prepared and after use in propane ammoxidation, using XRD, XPS, Raman spectroscopy, and transmission electron microscopy together with electron diffraction and X-ray microanalysis. Activity tests of the freshly prepared samples reveal a remarkable activation behaviour with time-on-stream under influence from the reaction medium. During the first 15-50 h on-stream, a considerable increase in the activity and the selectivity to acrylonitrile is observed in parallel with a decrease in the selectivity to waste products. The duration of the activation period depends on the W-content and increases with increase of the latter. Characterization with TEM, electron diffraction, and X-ray microanalysis show that the activation of the catalyst precursor under reaction conditions results in the formation of an approximate to Sb(V, W)O-4 phase of rutile-type, which is active and selective to acrylonitrile formation. The aluminum in the catalysts is present in form of delta-Al2O3, which serves as a catalyst support. Analysis of the catalysts and their precursors with XPS shows coverage of the alumina surface with oxides with Sb, V, and W, and the Raman spectra show the presence of tetrahedral and octahedral tungsten oxide species being attached to the alumina surface. Both XPS and X-ray microanalysis results indicate that the surfaces and the external layers of the precursors are enriched with antimony. Activity test of an Al-Sb-V-W-oxide catalyst with Sb:V:W = 5 : 1:2 and 50 wt% Al2O3, using a feed which is stoichiometric with respect to acrylonitrile formation, shows that the selectivity to acrylonitrile is 48% at 77% propane conversion, corresponding to a yield of 37%. Comparison with Sb-V-oxide and Al-Sb-V-oxide preparations reveals a substantial improvement of the catalytic properties with the addition of Al and W to Sb-V-oxide. (C) 1999 Academic Press.},
  author       = {Nilsson, J and Landa-Canovas, AR and Hansen, Staffan and Andersson, Arne},
  issn         = {1090-2694},
  keyword      = {propane,ammoxidation,acrylonitrile formation,Al-Sb-V-oxide catalysts,catalyst characterization,XRD,XPS,Raman spectroscopy,transmission,electron microscopy,electron diffraction,X-ray microanalysis},
  language     = {eng},
  number       = {2},
  pages        = {442--457},
  publisher    = {Elsevier},
  series       = {Journal of Catalysis},
  title        = {An investigation of the Al-Sb-V-W-oxide system for propane ammoxidation},
  url          = {http://dx.doi.org/10.1006/jcat.1999.2570},
  volume       = {186},
  year         = {1999},
}