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Title: Chemical kinetics of the gas-phase reaction between uranium hexafluoride and hydrogen

Abstract

A study was made of the chemical kinetics of the homogeneous gas-phase reaction between uranium hexafluoride and hydrogen by measuring the rate of disappearance of UF/sub 6/. It has been concluded that the rate-limiting step for which the kinetics have been measured is UF/sub 6/ + HF + H (2). The reaction has been studied in a steady-state flow system over a temperature range of approx.625 to 825 K. Various surface-to-volume ratios were employed to aid in distinguishing gas-phase reactions from surface reactions. The steady-state concentration of the UF/sub 6/ after reaction with H/sub 2/ was monitored in a special multipass infrared spectrophotometer at the 626-cm/sup -1/ absorption band of UF/sub 6/. The principal problems were corrosion, plugging, surface intrusion, and the deleterious effects of minute traces of water; these problems have greatly slowed progress in this field. Several series of measurements involving different initial species concentrations and residence times, with each series at constant temperature, show that the rate is first order in UF/sub 6/. Our measurements yield a dependable Arrhenius curve in terms of a second-order expression for k, the bimolecular specific reaction rate constant for the disappearance of UF/sub 6/. It is believed that this overall ratemore » of the disappearance of UF/sub 6/ is somewhat less than twice that of the critical reaction step 2, indicated above, so that the specific reaction rate constant k/sub 2/ is approx.8.7 c 10/sup 14/ exp(-34550 kcal/RT) cm/sup 3/ mol/sup -1/ s/sup -1/. Conclusions have been reached concerning the relative importance of the various elementary reaction steps involved in the chemical mechanism.« less

Authors:
 [1];
  1. Mote Marine Lab., Sarasota, FL
Publication Date:
OSTI Identifier:
5678931
Resource Type:
Journal Article
Journal Name:
J. Phys. Chem.; (United States)
Additional Journal Information:
Journal Volume: 85:25
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; HYDROGEN; CHEMICAL REACTION KINETICS; URANIUM HEXAFLUORIDE; ARRHENIUS EQUATION; EXPERIMENTAL DATA; HIGH TEMPERATURE; INFRARED SPECTRA; ACTINIDE COMPOUNDS; DATA; ELEMENTS; EQUATIONS; FLUORIDES; FLUORINE COMPOUNDS; HALIDES; HALOGEN COMPOUNDS; INFORMATION; KINETICS; NONMETALS; NUMERICAL DATA; REACTION KINETICS; SPECTRA; URANIUM COMPOUNDS; URANIUM FLUORIDES; 400702* - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials; 400201 - Chemical & Physicochemical Properties

Citation Formats

Myerson, A L, and Chludzinski, Jr, J J. Chemical kinetics of the gas-phase reaction between uranium hexafluoride and hydrogen. United States: N. p., 1981. Web. doi:10.1021/j150625a040.
Myerson, A L, & Chludzinski, Jr, J J. Chemical kinetics of the gas-phase reaction between uranium hexafluoride and hydrogen. United States. https://doi.org/10.1021/j150625a040
Myerson, A L, and Chludzinski, Jr, J J. 1981. "Chemical kinetics of the gas-phase reaction between uranium hexafluoride and hydrogen". United States. https://doi.org/10.1021/j150625a040.
@article{osti_5678931,
title = {Chemical kinetics of the gas-phase reaction between uranium hexafluoride and hydrogen},
author = {Myerson, A L and Chludzinski, Jr, J J},
abstractNote = {A study was made of the chemical kinetics of the homogeneous gas-phase reaction between uranium hexafluoride and hydrogen by measuring the rate of disappearance of UF/sub 6/. It has been concluded that the rate-limiting step for which the kinetics have been measured is UF/sub 6/ + HF + H (2). The reaction has been studied in a steady-state flow system over a temperature range of approx.625 to 825 K. Various surface-to-volume ratios were employed to aid in distinguishing gas-phase reactions from surface reactions. The steady-state concentration of the UF/sub 6/ after reaction with H/sub 2/ was monitored in a special multipass infrared spectrophotometer at the 626-cm/sup -1/ absorption band of UF/sub 6/. The principal problems were corrosion, plugging, surface intrusion, and the deleterious effects of minute traces of water; these problems have greatly slowed progress in this field. Several series of measurements involving different initial species concentrations and residence times, with each series at constant temperature, show that the rate is first order in UF/sub 6/. Our measurements yield a dependable Arrhenius curve in terms of a second-order expression for k, the bimolecular specific reaction rate constant for the disappearance of UF/sub 6/. It is believed that this overall rate of the disappearance of UF/sub 6/ is somewhat less than twice that of the critical reaction step 2, indicated above, so that the specific reaction rate constant k/sub 2/ is approx.8.7 c 10/sup 14/ exp(-34550 kcal/RT) cm/sup 3/ mol/sup -1/ s/sup -1/. Conclusions have been reached concerning the relative importance of the various elementary reaction steps involved in the chemical mechanism.},
doi = {10.1021/j150625a040},
url = {https://www.osti.gov/biblio/5678931}, journal = {J. Phys. Chem.; (United States)},
number = ,
volume = 85:25,
place = {United States},
year = {1981},
month = {12}
}