Sodium exchange over H-EU-1. zeolite. Part II: Catalytic properties
Martins, J; Birot, E; Guillon, E; Lemos, F; Ramoa Ribeiro, F; Magnoux, P; Laforge, S
| HERO ID | 2907237 |
|---|---|
| In Press | No |
| Year | 2013 |
| Title | Sodium exchange over H-EU-1. zeolite. Part II: Catalytic properties |
| Authors | Martins, J; Birot, E; Guillon, E; Lemos, F; Ramoa Ribeiro, F; Magnoux, P; Laforge, S |
| Journal | Microporous and Mesoporous Materials |
| Volume | 171 |
| Page Numbers | 238-245 |
| Abstract | Three different model reactions (methylcyclohexane, m-xylene and 1,3,5-trimethylbenzene transformations) were studied over a series of partially Na-exchanged H-EU-1 zeolites. In the case of methylcyclohexane transformation, the catalytic activity was shown to be directly correlated to the concentrations and strength distribution of the acid sites. Consequently, a maximum in activity and turn-over frequency (TOF) was obtained for an exchange ratio comprised between 26% and 34%, for which the proportion of very strong acid sites was very high. An acidity activity correlation, based on the Polanyi principle, was successfully applied to this reaction. This was not the case for m-xylene and 1,3,5-trimethylbenzene transformations. During those reactions, the activity and TOF decreased with the protonic site concentration, hence with the increase of the exchange ratio, the activity loss being more pronounced for low exchange ratios. Poisoning experiments using gamma-collidine indicated that two kinds of external acid sites could be distinguished, depending on their locations, that is, at the pore mouths and in 12-ring pockets. The fast exchange by sodium cations of the latter sites, which would be particularly active in m-xylene and 1,3,5-trimethylbenzene transformations, could explain the evolution of these activities. (C) 2012 Elsevier Inc. All rights reserved. |
| Doi | 10.1016/j.micromeso.2012.09.041 |
| Wosid | WOS:000316437800032 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Keyword | EU-1 zeolite; Sodium exchange; Model reactions; Acidity-activity relationship; External acid sites |