Publication: Interactions of amino acids with H-ZSM-5 zeolite: An embedded ONIOM study
Issued Date
2008-10-29
Resource Type
ISSN
00222860
Other identifier(s)
2-s2.0-53049091111
Rights
Mahidol University
Rights Holder(s)
SCOPUS
Bibliographic Citation
Journal of Molecular Structure. Vol.889, No.1-3 (2008), 81-88
Suggested Citation
Bundet Boekfa, Piboon Pantu, Jumras Limtrakul Interactions of amino acids with H-ZSM-5 zeolite: An embedded ONIOM study. Journal of Molecular Structure. Vol.889, No.1-3 (2008), 81-88. doi:10.1016/j.molstruc.2008.01.026 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/19058
Research Projects
Organizational Units
Authors
Journal Issue
Thesis
Title
Interactions of amino acids with H-ZSM-5 zeolite: An embedded ONIOM study
Author(s)
Other Contributor(s)
Abstract
The adsorption of glycine and l-alanine on the H-ZSM-5 zeolite has been studied at an embedded ONIOM (MP2/6-31G(d,p):UFF) level of theory. The most stable adsorption structure involves ion-pair interactions between the protonated amino acid and the anionic zeolite framework. The adsorption energy is computed to be -31.3 and -34.8 kcal/mol for glycine and l-alanine, respectively. Two hydrogen bonded complexes are identified: one is the cyclic double hydrogen bonded complex via the interactions of the carboxyl group and the zeolite acid site having adsorption energies of -25.4 and -30.0 kcal/mol for glycine and l-alanine, respectively. The second is the hydrogen bonded complex via the interactions of the hydroxyl group and the zeolite acid site having weak interaction energies, -20.7 and -23.9 kcal/mol for glycine and l-alanine, respectively. The zwitterion form is not found in the acidic H-ZSM-5 due to the acid-base reaction, but the glycine zwitterion is found to be stably adsorbed on the Na-ZSM-5 with the adsorption energy of -24.8 kcal/mol. In addition to the interactions with the Brønsted acid site of the zeolite, the interactions with the nearby oxygen framework and van der Waals interactions with the zeolite walls are also found to be important for stabilizing the adsorbed amino acids and zwitterion, suggesting the role of the zeolite framework as a "solid solvent molecule". © 2008 Elsevier B.V. All rights reserved.