Combined MAS NMR and X-ray powder diffraction structural characterization of hydrofluorocarbon-134 adsorbed on zeolite NaY: Observation of cation migration and strong sorbate-cation interactions

Journal Article · Wed Feb 26 04:00:00 EST 1997 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja963565x· OSTI ID:466338

Grey, C P; Poshni, F I ^[1]; Gualtieri, A F ^[2]; Norby, P ^[1]; Hanson, J C ^[3]; Corbin, D R ^[4]

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1. SUNY Stony Brook, NY (United States)
2. Universita di Modena (Italy)
3. Brookhaven National Lab., Upton, NY (United States)
4. DuPont Central Research and Development, Wilmington, DE (United States)

{sup 23}Na MAS NMR and synchrotron X-ray powder diffraction methods have been used to study the binding of hydrofluorocarbon-134 (HFC-134, CF{sub 2}HCF{sub 2}H) in zeolite NaY. A contraction of the volume of the unit cell is observed on gas adsorption, and the interaction of HFC-134 with the extraframework sodium cations is so strong that extraframework sodium cations in the sodalite cages (site I`) migrate into the supercages. These sodium cations are found on positions close to the site III` positions of zeolite NaX. Both ends of the HFC molecules are bound sodium cations, the HFC molecule bridging the site II and III` cations in the supercages. The strong cation-HFC interaction results in a considerable displacement of the sodium site II cation along the [111] direction into the supercage and an increase in the T-O-T bond angle for the three oxygen atoms coordinated to this cation. A decrease in the {sup 23}Na quadrupole coupling constant on HFC adsorption from 4.4 to less than 2.8 MHz, for the sodium cations originally located in the sodalite cages (site I`), is consistent with the sodium cation migrations. 26 refs., 7 figs., 5 tabs.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 466338
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 8 Vol. 119; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ATOMS
CATIONS
CHEMICAL BONDS
GAS CHROMATOGRAPHY
HYDROCARBONS
MOLECULES
NUCLEAR MAGNETIC RESONANCE
NUMERICAL DATA
OXYGEN
POWDERS
SIMULATION
SODIUM 23
SYNCHROTRON RADIATION
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION
ZEOLITES