Structures of dehydrated potassium zeolite L at 298 and 78 K and at 78 K containing sorbed perdeuteriobenzene

Journal Article · Thu Nov 02 04:00:00 EST 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100359a031· OSTI ID:6788367

Newsam, J M ^[1]

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1. Exxon Research and Engineering Co., Annandale, NJ (USA)

The complete structures of dehydrated potassium zeolite L, K{sub 9}Al{sub 9}Si{sub 27}O{sub 72}, at 298 and 78 K and of the same zeolite at 78 K containing, on average, 1 molecule of perdeuteriobenzene/unit cell have been determined by powder neutron diffraction. Comparison with earlier literature data indicates that little change in structure accompanies dehydration, benzene sorption, or temperature change 298 K {ge} T {ge} 78 K. The use of powder neutron diffraction has enabled a direct measure of the aluminum partitioning between the two inequivalent T-sites in the structure that, consistent with the complementary measure from bond length arguments, demonstrates a distinct aluminum preference for the 12-ring, Sil (T4) sites. The nonframework K{sup +} configuration shows only subtle changes over the range of conditions studied. Perdeuteriobenzene is observed at 78 K in capping positions above the channel wall (type D) K{sup +} cations. Simple atom-atom potential modeling of the benzene site based on the structural results yields only a small activation barrier to benzene molecule reorientation.

• OSTI ID: 6788367
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:22; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
360102 -- Metals & Alloys-- Structure & Phase Studies
AROMATICS
BENZENE
COHERENT SCATTERING
DATA
DATA ANALYSIS
DIFFRACTION
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
LOW TEMPERATURE
MATERIALS
MEASURING INSTRUMENTS
MEASURING METHODS
MEDIUM TEMPERATURE
MINERALS
MOLECULAR STRUCTURE
NEUTRON DIFFRACTION
NUMERICAL DATA
ORGANIC COMPOUNDS
SCATTERING
ZEOLITES