Temperature dependence of copper(II) migration and formation of new copper(II) species during catalytic propylene oxidation on copper(II)-exchanged Y zeolite and comparison with X zeolite

Journal Article · Thu Sep 20 04:00:00 EDT 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100382a055· OSTI ID:6409782

Yu, Jongsung; Kevan, L ^[1]

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1. Univ. of Houston, TX (USA)

Electron spin resonance (ESR) and electron spin-echo modulation (ESEM) spectroscopies have been used to characterize the aqueous coordination and location of catalytically active Cu(II) cation-exchanged into K-Y zeolite. The higher Si/Al ratio in CuK-Y compared to CuK-X gives rather different ESR parameters for Cu(II). Under complete hydration, ESR indicates freely rotating Cu(II) ions in the {alpha} cage, and the corresponding ESEM indicates six directly bound water molecules. Under partial dehydration, ESR shows that Cu(II) becomes immobilized near the six-ring window of the zeolite, and the corresponding ESEM indicates coordination to three water molecules. Upon dehydration and at high temperature, ESR shows that the cupric ions mainly move into the {beta} cage and hexagonal prism. The Cu(II)-catalyzed oxidation of propylene over dehydrated CuK-Y zeolite with low Cu(II) exchange was studied over the temperature range of 160 to 400{degree}C under conditions of excess oxygen in a flow system in order to investigate the temperature dependence of the catalytic activity, the migration of Cu(II) species, the Cu(II) coordination complexes formed in the zeolite framework, and the comparison with previous results on CuK-X zeolite. The catalytic activity of CuK-Y was comparable to that of CuK-X under the same conditions.

• OSTI ID: 6409782
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:19; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKENES
CATALYSIS
CHEMICAL REACTIONS
COMPLEXES
COPPER COMPLEXES
ELECTRON SPIN RESONANCE
HIGH TEMPERATURE
HYDROCARBONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MAGNETIC RESONANCE
MATERIALS
MINERALS
ORGANIC COMPOUNDS
OXIDATION
PROPYLENE
RESONANCE
SPECTROSCOPY
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPLEXES
ZEOLITES