The oxidation of uranium(IV) ions by nitrous acid in 30% tri-butyl phosphate

V. S. Koltunov, Robin J. Taylor, V. I. Marchenko, O. A. Savilova,  and K. N. Dvoeglazov

Summary

The kinetics of the oxidation of U(IV) ions by nitrous acid in a 30% TBP solution have been determined. The rate equation was found to be:

-d[U(IV)]/dt = k2a([U(IV)][HNO2][HNO3][H2O])/([HNO3]23[HNO3][H2O]+β4[H2O]2),

where, k2a=0.405±0.055 M-1 min-1 at 55 °C (β3≈0.08; β4≈0.007) and the activation energy was E=112±17 kJ mol-1. The reaction mechanism appeared to involve interaction with the 1st hydrolysis product of U(IV)–UOH3+. The data is compared with a previous study of the nitric acid oxidation of U(IV) in 30% TBP. This reaction is autocatalytic due to the formation of nitrous acid during the reaction. The kinetics of the decomposition of HNO2 in 30% TBP (in the absence of U(IV)) have also been reported.

Purchase article
Get instant unlimited access to the article.
$42.00
Log in
Already have access? Please log in.


or
Log in with your institution

Journal + Issues

Radiochimica Acta publishes original papers, review articles, and “rapid communications” (short articles of a more timely interest) on all chemical aspects of nuclear science and technology. The journal is geared toward scientists who are actively engaged in research work.

Search