Article Dans Une Revue Nouveau Journal de Chimie Année : 1985

The catalytic reactions of CO and H2O in the presence of hydrocarbons: role of the water gas shift reaction in toluene steam dealkylation over Group VIII metal catalysts

Résumé

The water gas shift (WGS) reaction was studied in the presence of PhMe as a secondary reaction of the PhMe steam dealkylation (TSDA) because the activity in WGS substantially influences the performance of the catalyst in TSDA since CO is a selective inhibiting product of TSDA, and little is known of the activity of supported Group VIII metal catalysts in WGS performed under these conditions. At 713 K the following sequence for relative activity is obtained: Rh, 52; Ru, 20; Ni, 19; Pt, 8.8; Ir, 8.2; Pd, 7.0. Rh exhibits the same activity in TSDA (NT) and in WGS (NWGS); nevertheless, TSDA is strongly support-sensitive (NT, Rh/Al2O3 > NT, Rh/SiO2), whereas WGS is not. On the other hand, Pt is much more active in WGS than in TSDA, which limits the apparent activity of this metal in CO conversion. Ru occupies an intermediate position, it resembles Pt (NWGS .mchgt. NT) and behaves like Rh (low conversion of CO during TSDA). Results are examd. in the light of the 2 mechanisms previously proposed for WGS, the formate mechanism and the surface carbon mechanism. The latter is predominant in the conversion of CO at 713 K and accounts for the absence of support effect in WGS on Rh catalysts.

Domaines

Fichier non déposé

Dates et versions

hal-00179680 , version 1 (16-10-2007)

Identifiants

  • HAL Id : hal-00179680 , version 1

Citer

Daniel Duprez, Gerard Delahay, Abdelhalim Miloudi. The catalytic reactions of CO and H2O in the presence of hydrocarbons: role of the water gas shift reaction in toluene steam dealkylation over Group VIII metal catalysts. Nouveau Journal de Chimie, 1985, 9, pp.531-534. ⟨hal-00179680⟩

Collections

87 Consultations
0 Téléchargements

Partager

  • More