Arsenova-Haertel, N. and Bludau, H. and Schumacher, R. and Haag, W. O. and Karge, H. G. and Brunner, Eike and Wild, U. (2000) Catalytic and sorption studies related to the para selectivity in the ethylbenzene disproportionation over H-ZSM-5 catalysts. JOURNAL OF CATALYSIS, 191 (2). pp. 326-331. ISSN 0021-9517
Full text not available from this repository.Abstract
Earlier kinetic investigations of ethylbenzene disproportionation over medium-pore zeolite catalysts revealed that the para selectivity for the diethylbenzenes produced increases strongly with crystal size. Two models for diethylbenzene isomerization have been offered as a possible explanation for the observed dependence: secondary isomerization on the external surface of the zeolite crystallites (I) and isomerization inside the zeolite pores combined with faster diffusion of para-diethylbenzene (II). The present paper describes additional investigations, aimed at obtaining evidence for one of these models. Thus, in a series of catalytic experiments the effect of the deactivation of the outer crystallite surface of H-ZSM-5 samples on the distribution of the diethylbenzene product was examined. Further, sorption of pure para-, meta-, and ortho-diethylbenzene from the gas phase over H-ZSM-5 was studied by means of in situ infrared spectroscopy. Both types of investigations provided evidence that diethylbenzene isomerization occurs in the interior of H-ZSM-5. Thus, the para-selective features of H-ZSM-5 reflect the interplay of catalytic reaction and mass transfer phenomena. It was additionally shown that para-diethylbenzene and meta-diethylbenzene are reversibly sorbed in H-ZSM-5 in contrast to the ortho isomer, which cannot enter the zeolite pore system in the temperature range examined (359-522 K). (C) 2000 Academic Press.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ZEOLITE CATALYSTS; TOLUENE DISPROPORTIONATION; XYLENE ISOMERIZATION; ALKYLATION; METHANOL; SURFACE; ZSM-5; H-ZSM-5-zeolite; para selectivity; ethylbenzene disproportionation; diethylbenzene isomerization; adsorption; IR spectroscopy |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie > Alumni or Retired > Prof. Dr. Eike Brunner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 10 May 2022 13:53 |
| Last Modified: | 10 May 2022 13:53 |
| URI: | https://pred.uni-regensburg.de/id/eprint/42567 |
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