High-temperature NMR study of zeolite Na-A: Detection of a phase transition
- Univ. of Nijmegen (Netherlands)
The zeolite Linde 4A is studied by {sup 23}Na, {sup 27}al, and {sup 29}Si NMR at temperatures up to 953 K. {sup 23}Na NMR shows that the quadrupole interaction of sodium ions sited at 6-rings decreases when the temperature increases. With the aid of two-dimensional nutation and exchange experiments it can be shown that large-amplitude motions of the sodium ions, which in principle could explain a decrease of quadrupole interactions, do not occur. The decrease of the quadrupole interaction can be interpreted in terms of a phase transition. From a comparison of the NMR spectra of {sup 23}Na and {sup 27}Al it is concluded that the zeolite framework undergoes a major structural change upon increasing the temperature, before the sodium ions are displaced at higher temperatures. The exchange of sodium ions for potassium ions shifts this transition to higher temperatures.
- OSTI ID:
- 5447522
- Journal Information:
- Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:2; ISSN 0022-3654; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ALUMINIUM 27
ALUMINIUM ISOTOPES
CATALYSIS
CATALYSTS
DATA
DIAGRAMS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
MINERALS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
PHASE DIAGRAMS
PHASE STUDIES
POTASSIUM COMPOUNDS
RESONANCE
SILICON 29
SILICON ISOTOPES
SODIUM 23
SODIUM COMPOUNDS
SODIUM ISOTOPES
SPECTRA
STABLE ISOTOPES
ZEOLITES