Kinetics of the Dehydration of the β-Cages of Sodium Faujasites as Studied by H-NMR Spectroscopy

Autor:	W. D. Basler, D. Carboo, A. Knöchel, H. T. Lechert
Rok vydání:	1992
Předmět:	Chemistry General Chemical Engineering Sodium Kinetics Enthalpy chemistry.chemical_element Activation energy medicine.disease Adsorption Physics::Atomic and Molecular Clusters medicine Proton NMR Physical chemistry Dehydration Physics::Chemical Physics Spectroscopy
Zdroj:	Berichte der Bunsengesellschaft für physikalische Chemie. 96:545-549
ISSN:	0005-9021
Popis:	The kinetics of the dehydration of the β-cages of sodium faujasites have been studied by NMR methods. For Na — Y type (Si/Al > 2) the rate of passing from the β-cages into the supercages is slow and only weakly dependent on temperature (activation energy EA = 4.1 kJ/mol). This is in contrast to the strongly temperature dependent (Ea = 100 kJ/mol) rate of penetration from the supercages into the β-cages. A model is proposed assuming the formation of a water-ion complex. The slow rate is explained by a negative complex formation entropy (−40R) due to spatial constraints in the β-cages. The activation energy is small because the enthalpy of the penetration is nearly canceled by the negative complex formation enthalpy.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8aefaa251f20b98b9543a5508cda2c20 https://doi.org/10.1002/bbpc.19920960406 Zobrazit plný text záznamu Plný text