par Zhuang, Yiping;Frennet, Alfred 
Référence Applied catalysis. A, General, 177, 2, page (205-217)
Publication Publié, 1999-02
Référence Applied catalysis. A, General, 177, 2, page (205-217)
Publication Publié, 1999-02
Article révisé par les pairs
| Résumé : | Kinetic studies of methylcyclopentane (MCP) ring opening on EuroPt-1 (a 6.3 wt% Pt/SiO2) were carried out under both steady state and concentration step change conditions. At steady state, the activity changes monotonically on increasing MCP pressure and exhibits a maximum with hydrogen pressure. The product ratio of 2-methylpentane (2MP) to n-hexane (nH) increases with increasing MCP pressure and decreases with hydrogen pressure. No change was observed for the product ratio of 2MP to 3-methylpentane (3MP). Following a step change up of MCP pressure from 0 to ca. 9 Torr, an overshoot response at 60 Torr H2 and a monotonic increase at 750 Torr H2 were observed for all the products. The height of the overshoot response of nH is more significant than that of 2MP and 3MP and decreases as the temperature increases. Both 2MP/nH and 2MP/3MP change with time during a step change up of MCP pressure. A maximum for 2MP/3MP and a value less than unity for 2MP/nH were observed. The results were discussed on the basis of a parallel reaction model: one forming nH and the other forming MPs (2MP+3MP). A reactive adsorption mechanism for the reaction forming nH and a dissociative adsorption mechanism for the reaction forming MPs were proposed for the MCP adsorption-dehydrogenation process. A molecular hydrogen associated with an active site is most likely involved in the C-C bond rupture, which is concluded to be the rate-controlling step in this work. © 1999 Elsevier Science B.V. All rights reserved. |
