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

✍ Scribed by Jonathan C. Otamiri; Arne Andersson

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 636 KB
• Volume: 3
• Category: Article
• ISSN: 0920-5861
• DOI: 10.1016/0920-5861(88)87010-x

✦ Synopsis

A thorough kinetic investigation of the anmnoxidation of toluene over a V 0 catalyst was carried out. Pressures of reactants were varied and rates 30# formation of benzonitrile and benzaldehvde were determined. Kinetic exoressions completely describing experimental datawere derived. A mechanism is proposed on basis of both rate equations and other types of information published in the literature. The (010) plane of V 0 is considered to be the active plane. An ensemble of 4 V=O species, havih5neighbouring 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 anonia 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.