Kinetics and mechanisms in the ammoxidation of toluene over a V2O5 catalyst. Part 1: Selective reactions

Research output: Contribution to journalArticle

Abstract

A thorough kinetic investigation of the ammoxidation of toluene over a V2O5 catalyst was carried out. Pressures of reactants were varied and rates for formation of benzonitrile and benzaldehyde were determined. Kinetic expressions completely describing experimental data were derived. A mechanisms is proposed on basis of both rate equations and other types of information published in the literature. The (010) plane of V2O5 is considered to be the active plane. An ensemble of 4 V=O species, having neighbouring vanadium ions exposed, is the active site. The rate-determining step for formation of aldehyde is the abstraction of a hydrogen atom from the methyl group. Nitrile is formed from two routes. In one of the routes, the active site reacts with one ammonia molecule, which constitutes a rate-limiting step. In the second route, the active site chemisorbs two ammonia species, and the rate-determining step is the hydrogen abstraction from the methyl group. The results indicate that the electronic properties of the surface are greatly affected by adsorption of ammonia.

Details

Authors
  • J Otamiri
  • Arne Andersson
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Engineering
Original languageEnglish
Pages (from-to)211-222
JournalCatalysis Today
Volume3
Issue number2-3
Publication statusPublished - 1988
Publication categoryResearch
Peer-reviewedYes