NMR study of the distribution of aromatic molecules in NaY zeolite

Journal Article · Wed Jan 09 23:00:00 EST 1991 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100154a056· OSTI ID:5774852

Chmelka, B F; Pearson, J G; Liu, S B; Ryoo, R; de Menorval, L C; Pines, A ^[1]

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1. Lawrence Berkeley Lab., CA (USA)

Local and macroscopic distributions of adsorbed benzene, 1,3,5-trimethylbenzene, and hexamethylbenzene (HMB) molecules among the intracrystalline cavities of NaY zeolite samples have been investigated by {sup 129}Xe and multiple-quantum NMR. Xenon-129 NMR, a sensitive probe of macroscopic distributions of molecules in zeolites at room temperature, demonstrates the importance of sample heat treatment in distributing an adsorbate homogeneously throughout a collection of zeolite particles. NaY samples containing organic guests adsorbed at temperatures near the bulk species melting point produce multiple or broad xenon lines characteristic of macroscopic (i.e., interparticle) adsorbate concentration gradients. After thorough heat treatment of the samples at elevated temperatures, the xenon spectrum collapses to a single sharp line, consistent with a macroscopically uniform distribution. For HMB adsorbed in NaY, counting hydrogen clusters by multiple-quantum NMR reveals intraparticle HMB distributions consistent with one molecular per cavity at low loadings (average bulk loading {le} 1 molecule per cavity) and two molecules per cavity at higher loadings.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5774852
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:1; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
BENZENE
DATA
DAYS LIVING RADIOISOTOPES
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
INORGANIC ION EXCHANGERS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ION EXCHANGE MATERIALS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAGNETIC RESONANCE
MATERIALS
MEASURING METHODS
MEDIUM TEMPERATURE
MINERALS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
RADIOISOTOPES
RESONANCE
STABLE ISOTOPES
SURFACE PROPERTIES
XENON 129
XENON ISOTOPES
ZEOLITES