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

Abstract

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.

Authors:
;  [1]; ;  [2]
  1. Muroran Inst. of Tech., Hokkaido (Japan). Dept. of Applied Chemistry
  2. RIKEN, Wako, Saitama (Japan). Inst. of Physical and Chemical Research
Publication Date:
OSTI Identifier:
691293
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 103; Journal Issue: 35; Other Information: PBD: 2 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; ISOTOPIC EXCHANGE; URANIUM 235; URANIUM 238; URANIUM PENTAFLUORIDE; ACTIVATION ENERGY; KINETICS; ARRHENIUS EQUATION; URANIUM HEXAFLUORIDE

Citation Formats

Kuga, Yoshikazu, Ando, Koji, Onoe, Jun, and Takeuchi, Kazuo. Activation energy for isotope exchange reaction between {sup 235}UF{sub 5} nanoparticles and {sup 238}UF{sub 6} gas. United States: N. p., 1999. Web. doi:10.1021/jp991484s.
Kuga, Yoshikazu, Ando, Koji, Onoe, Jun, & Takeuchi, Kazuo. Activation energy for isotope exchange reaction between {sup 235}UF{sub 5} nanoparticles and {sup 238}UF{sub 6} gas. United States. doi:10.1021/jp991484s.
Kuga, Yoshikazu, Ando, Koji, Onoe, Jun, and Takeuchi, Kazuo. Thu . "Activation energy for isotope exchange reaction between {sup 235}UF{sub 5} nanoparticles and {sup 238}UF{sub 6} gas". United States. doi:10.1021/jp991484s.
@article{osti_691293,
title = {Activation energy for isotope exchange reaction between {sup 235}UF{sub 5} nanoparticles and {sup 238}UF{sub 6} gas},
author = {Kuga, Yoshikazu and Ando, Koji and Onoe, Jun and Takeuchi, Kazuo},
abstractNote = {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.},
doi = {10.1021/jp991484s},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
number = 35,
volume = 103,
place = {United States},
year = {1999},
month = {9}
}