Mechanism of the hydrodenitrogenation of quinoline over NiMo(P)/Al{sub 2}O{sub 3} catalysts
- Federal Inst. of Technology, Zuerich (Switzerland). Lab. for technical Chemistry
The hydrodenitrogenation (HDN) of quinoline and its reaction intermediates was studied over NiMo(P)/Al{sub 2}O{sub 3} catalysts. Phosphorus exhibited a promotional effect on the HDN of quinoline and ortho-propylaniline and a negative effect on the HDN of decahydroquinoline and on the hydrogenation of 1-methylcyclohexene in its simultaneous reaction with quinoline. The HDN of quinoline was found to take place via two pathways; via the saturated intermediates decahydroquinoline and propylcyclohexylamine, and via the aromatic intermediates 1,2,3,4-tetrahydroquinoline and ortho-propylaniline. Although propylcyclohexane is the main HDN product in both reaction paths, formation of propylbenzene is relatively favored in the latter path. Thus, the relative contributions of the two reaction paths in the quinoline HDN network could be estimated from the HDN product composition. In contrast to previous suggestions, the 1,2,3,4-tetrahydroquinoline-ortho-propylaniline reaction path was found to be nonnegligible: About 40% of the quinoline HDN takes place via this reaction path at 643 K, 3.0 MPa, and P{sub H{sub 2}S} = 6.5 kPa, and about 35% at 623 K. H{sub 2}S had an effect opposite that of phosphorus on the HDN of decahydroquinoline and ortho-propylaniline. H{sub 2}S as well as phosphorus had a small positive effect on the HDN of quinoline. This is due to a subtle balance between their opposite effects on the HDN of decahydroquinoline as well as ortho-propylaniline. Because of this, and of the opposite effect of phosphorus as well as H{sub 2}S on the HDNs of these two molecules, the effect of phosphorus and H{sub 2}S on the HDN of quinoline is a subtle balance between the two HDN pathways, the catalyst composition, and the reaction conditions.
- OSTI ID:
- 672457
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 179; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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