IR study of 1-hexene isomerization on HZSM-5 zeolites

Bezouhanova, C.; Lechert, H.; Taralanska, G.; Meyer, Andreas

doi:10.1007/bf02073795

Cited by 8 publications

(9 citation statements)

References 9 publications

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“…In the case of the isolated 54T cluster, the calculated stretching frequency of the acidic H−O bond is 3623 cm . 13,[38][39][40] Besides, the optimized geometric data of the 54T cluster were found to be in general agreement with the previous computational results concerning H-ZSM-5 36,37 and those of the crystal structure of H-ZSM-5 found in XRD study. 41 Therefore, it is a good justification to use the 54T model to represent a real ZSM-5 zeolite.…”

Section: Models and Computational Methodssupporting

confidence: 89%

“…suggesting that the TS1 exhibits significant ionic characteri- , reported by Lechert et al 12 and Bezouhanova et al, 13 respectively. Charge distribution calculations according to the Mulliken population analyses give a further insight into the high carbocation character of the TS1.…”

mentioning

confidence: 75%

“…Although extensive experimental studies have been performed to identify the reaction mechanism, 12-25 they often disagree on the intermediates and elementary steps involved in the reaction. Lechert et al 12 and Bezouhanova et al 13 reported upon a basis of IR spectroscopy investigation that the double-bond isomerization of 1-hexene involves formation of carbenium ion intermediate on H-ZSM-5. Campbell 19 and Pines 20 reached the conclusion that the isomerization of 1-hexene to 2-hexene proceeds via deprotonation from the adsorbed carbenium ion.…”

Section: Introductionmentioning

confidence: 99%

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Zeolite-catalyzed Isomerization of 1-Hexene to trans-2-Hexene: An ONIOM Study

Li¹,

Zhu²,

Liu³

et al. 2011

Bulletin of the Korean Chemical Society

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Details of the double-bond isomerization of 1-hexene over H-ZSM-5 were clarified using density functional theory. It is found that the reaction proceeds by a mechanism which involves the Brønsted acid part of the zeolite solely. According to this mechanism, 1-hexene is first physically adsorbed on the acidic site, and then, the acidic proton transfers to one carbon atom of the double bond, while the other carbon atom of the double bond bonds with the Brønsted host oxygen, yielding a stable alkoxy intermediate. Thereafter, the Brønsted host oxygen abstracts a hydrogen atom from the C 6 H 13 fragment and the C-O bond is broken, restoring the acidic site and yielding trans-2-hexene. The calculated activation barrier is 12.65 kcal/mol, which is in good agreement with the experimental value. These results well explain the energetic aspects during the course of double-bond isomerization and extend the understanding of the nature of the zeolite active sites.

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Section: Models and Computational Methodssupporting

confidence: 89%

mentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Zeolite-catalyzed Isomerization of 1-Hexene to trans-2-Hexene: An ONIOM Study

Li¹,

Zhu²,

Liu³

et al. 2011

Bulletin of the Korean Chemical Society

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“…In order to further validate the 3T cluster model, the vibrational frequencies were calculated. In the case of the isolated 3T cluster, the calculated stretching frequency of the acidic H-O bond is 3725i cm À1 , while the experimental data is of the order of 3610-3623i cm À1 [9,[33][34][35]. Clearly, the relative deviation is within 3%.…”

Section: Models and Computational Methodsmentioning

confidence: 88%

“…The reaction mechanism has been investigated intensively by experiment [9][10][11][12][13][14][15][16][17][18][19][20]. Bezouhanova et al [9] reported upon a basis of IR spectroscopy investigation that the double-bond isomerization of 1-hexene involves formation of carbenium ion intermediate on ZSM-5. Campbell [14] and Pines [15] suggested that the isomerization of 1-hexene to 2-hexene proceeds via deprotonation from the adsorbed carbenium ion.…”

Section: Introductionmentioning

confidence: 99%