Activation energy for isotope exchange reaction between {sup 235}UF{sub 5} nanoparticles and {sup 238}UF{sub 6} gas

Journal Article · Thu Sep 02 04:00:00 EDT 1999 · Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical

DOI:https://doi.org/10.1021/jp991484s· OSTI ID:691293

Kuga, Yoshikazu; Ando, Koji ^[1]; Onoe, Jun; Takeuchi, Kazuo ^[2]

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1. Muroran Inst. of Tech., Hokkaido (Japan). Dept. of Applied Chemistry
2. RIKEN, Wako, Saitama (Japan). Inst. of Physical and Chemical Research

The temperature dependence of the rates for two kinetic processes involved in the isotopic exchange reaction between {sup 235}U-enriched UF{sub 5} nanoparticles and natural UF{sub 6} gas was experimentally examined using a kinetic model that includes the fraction of high-reactivity molecules of UF{sub 5} on the outermost layer of the particles. The activation energies obtained from the Arrhenius plot for the fast process and the slow process were similar, 36.1 and 39.3 kJ/mol, respectively. This indicates that the two rate processes are mainly caused by the difference in the preexponential factor of the Arrhenius equation. It was suggested that such a difference in the reactivity of the UF{sub 5} molecules was caused by the difference in the adsorption configurations of UF{sub 6} molecules on the surface of UF{sub 5} molecules due to the steric hindrance of neighboring fluorine atoms.

• OSTI ID: 691293
• Journal Information: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 35 Vol. 103; ISSN 1089-5647; ISSN JPCBFK
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ACTIVATION ENERGY
ARRHENIUS EQUATION
ISOTOPIC EXCHANGE
KINETICS
URANIUM 235
URANIUM 238
URANIUM HEXAFLUORIDE
URANIUM PENTAFLUORIDE