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Kinetics and mechanisms in the ammoxidation of toluene over a V2O5 catalyst. Part 2: Non-selective reactions

Otamiri, J and Andersson, Arne LU (1988) In Catalysis Today 3(2-3). p.223-234
Abstract
In the ammoxidation of toluene over a V2O5 catalyst, the variation of initial rates with partial pressures of oxygen, toluene and ammonia was determined for formation of carbon oxides. Dependencies obtained were analyzed and expressed in terms of rate equations. It was found that CO and CO2 are initial products formed at different sites, none of which are involved in selective reactions. The mechanisms derived for the formation of the two oxides have many features in common. In each mechanism there are two parallel routes originating from the same active site, which is suggested to be an ensemble exposing vanadium ions and electrophilic oxygen species. One of the routes proceeds without participation of ammonia, while in the other route... (More)
In the ammoxidation of toluene over a V2O5 catalyst, the variation of initial rates with partial pressures of oxygen, toluene and ammonia was determined for formation of carbon oxides. Dependencies obtained were analyzed and expressed in terms of rate equations. It was found that CO and CO2 are initial products formed at different sites, none of which are involved in selective reactions. The mechanisms derived for the formation of the two oxides have many features in common. In each mechanism there are two parallel routes originating from the same active site, which is suggested to be an ensemble exposing vanadium ions and electrophilic oxygen species. One of the routes proceeds without participation of ammonia, while in the other route ammonia is adsorbed. In both routes, the rate-determining step can be considered to be one of the steps in a stepwise reoxidation process. The rates for formation of carbon oxides decrease strongly with increasing partial pressure of ammonia, which is due to a combined effect of introduction of a new reaction pathway and competitive adsorption between oxygen and ammonia. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Catalysis Today
volume
3
issue
2-3
pages
223 - 234
publisher
Elsevier
external identifiers
  • scopus:0040091810
ISSN
0920-5861
DOI
10.1016/0920-5861(88)87011-1
language
English
LU publication?
yes
id
e8d36580-19f4-442d-ad7e-44efb8365cb6 (old id 3917885)
date added to LUP
2013-07-05 12:04:15
date last changed
2017-08-27 05:19:04
@article{e8d36580-19f4-442d-ad7e-44efb8365cb6,
  abstract     = {In the ammoxidation of toluene over a V2O5 catalyst, the variation of initial rates with partial pressures of oxygen, toluene and ammonia was determined for formation of carbon oxides. Dependencies obtained were analyzed and expressed in terms of rate equations. It was found that CO and CO2 are initial products formed at different sites, none of which are involved in selective reactions. The mechanisms derived for the formation of the two oxides have many features in common. In each mechanism there are two parallel routes originating from the same active site, which is suggested to be an ensemble exposing vanadium ions and electrophilic oxygen species. One of the routes proceeds without participation of ammonia, while in the other route ammonia is adsorbed. In both routes, the rate-determining step can be considered to be one of the steps in a stepwise reoxidation process. The rates for formation of carbon oxides decrease strongly with increasing partial pressure of ammonia, which is due to a combined effect of introduction of a new reaction pathway and competitive adsorption between oxygen and ammonia.},
  author       = {Otamiri, J and Andersson, Arne},
  issn         = {0920-5861},
  language     = {eng},
  number       = {2-3},
  pages        = {223--234},
  publisher    = {Elsevier},
  series       = {Catalysis Today},
  title        = {Kinetics and mechanisms in the ammoxidation of toluene over a V2O5 catalyst. Part 2: Non-selective reactions},
  url          = {http://dx.doi.org/10.1016/0920-5861(88)87011-1},
  volume       = {3},
  year         = {1988},
}