Influence of Pt concentration on tungsten oxide-promoted zirconia during n-hexane isomerization

• Published in: Applied catalysis. A, General General, 2000-06, Vol.201 (1), p.37-43
• Main Authors: Falco, M.G., Canavese, S.A., Comelli, R.A., Fı́goli, N.S.
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts: preparations and properties; Chemistry; Exact sciences and technology; General and physical chemistry; n-Hexane isomerization; Platinum concentration; Surface hydrogen availability; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Tungsten oxide-promoted zirconia
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/S0926-860X(00)00417-8

The effect of platinum concentration on tungsten oxide-promoted zirconia over the catalytic activity for n-hexane isomerization was studied. Catalysts were prepared by impregnation of tungsten oxide-promoted zirconia reaching up to 1.50% platinum, followed by calcination at 500°C. The n-hexane reaction was studied at 200°C, 5.9 bar, WHSV 4 and H 2: n-hexane (molar) ratio 7. It was found that catalytic activity and stability increase for platinum concentrations above 0.05% because of higher hydrogen availability at the surface, measured as a function of the methylcyclopentane/C 6 isomers ratio. Further increments in platinum concentration do not produce important modifications in catalytic activity or hydrogen availability. Mechanical mixtures of Pt/SiO 2 and tungsten oxide-promoted zirconia present a lower conversion than platinum over tungsten oxide-promoted zirconia due to the larger distance between the acid and metallic functions.