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Kinetics of the reaction between plutonium (4) and neptunium (4) in nitric acid solution

Abstract

The kinetics of the oxidation of neptunium(IV) to neptunium(V) by tetravalent plutonium ions in solutions of HNO/sub 3/ + NaNO/sub 3/ at constant (..mu.. = 2) and variable (..mu.. = 0.7-2.0) ionic strengths of the solution was investigated by a spectrophotometric method. It was established that in the range of concentrations (Np(IV)) = (4.25-10.6) x 10/sup 13/; (Pu(IV)) = (2.6-3.9)x10/sup -3/ M; (H/sup +/) 0.37-1.91 M, a first order is observed with respect to the reagents, while the order of the reaction with respect to H/sup +/ ions is equal to -3. The average value of the true rate constant of the reaction is k = 27.9+-1.3 M/sup 2/xmin/sup -1/ at ..mu..=2 and 39/sup 0/C. It was shown that with increasing analytical concentration of HNO/sub 3/ and NO/sub 3//sup -/ ions (in a mixture of HNO/sub 3/ +HClO/sub 4/), the value of K decreases. On the basis of an invetigation of the dependence of the reaction rate on the temperature in the interval 31-44.8/sup 0/, we calculated the values of the energy (E = 34.6 kcal/mole), enthalpy (..delta..H* = 34 kcal/mole), free energy (..delta..F* = 19.6 kcal/mole, entropy (..delta..S* = 49 entropy units) of activation of the reaction and the  More>>
Publication Date:
Jan 01, 1976
Product Type:
Journal Article
Reference Number:
AIX-08-342844; EDB-78-038965
Resource Relation:
Journal Name: Radiokhimiya; (USSR); Journal Volume: 18:2
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; NEPTUNIUM; CHEMICAL REACTION KINETICS; PLUTONIUM; COMPARATIVE EVALUATIONS; COMPLEXES; ENTROPY; MEDIUM TEMPERATURE; NEPTUNIUM COMPOUNDS; NITRATES; NITRIC ACID; PH VALUE; PLUTONIUM COMPOUNDS; QUANTITY RATIO; ACTINIDE COMPOUNDS; ACTINIDES; ELEMENTS; HYDROGEN COMPOUNDS; INORGANIC ACIDS; KINETICS; METALS; NITROGEN COMPOUNDS; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; REACTION KINETICS; THERMODYNAMIC PROPERTIES; TRANSURANIUM COMPOUNDS; TRANSURANIUM ELEMENTS; 400702* - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials
OSTI ID:
5240666
Country of Origin:
USSR
Language:
Russian
Other Identifying Numbers:
Journal ID: CODEN: RADKA
Submitting Site:
INIS
Size:
Pages: 264-269
Announcement Date:
Dec 01, 1977

Citation Formats

Koltunov, V S, Zhuravleva, G I, and Marchenko, V I. Kinetics of the reaction between plutonium (4) and neptunium (4) in nitric acid solution. USSR: N. p., 1976. Web.
Koltunov, V S, Zhuravleva, G I, & Marchenko, V I. Kinetics of the reaction between plutonium (4) and neptunium (4) in nitric acid solution. USSR.
Koltunov, V S, Zhuravleva, G I, and Marchenko, V I. 1976. "Kinetics of the reaction between plutonium (4) and neptunium (4) in nitric acid solution." USSR.
@misc{etde_5240666,
title = {Kinetics of the reaction between plutonium (4) and neptunium (4) in nitric acid solution}
author = {Koltunov, V S, Zhuravleva, G I, and Marchenko, V I}
abstractNote = {The kinetics of the oxidation of neptunium(IV) to neptunium(V) by tetravalent plutonium ions in solutions of HNO/sub 3/ + NaNO/sub 3/ at constant (..mu.. = 2) and variable (..mu.. = 0.7-2.0) ionic strengths of the solution was investigated by a spectrophotometric method. It was established that in the range of concentrations (Np(IV)) = (4.25-10.6) x 10/sup 13/; (Pu(IV)) = (2.6-3.9)x10/sup -3/ M; (H/sup +/) 0.37-1.91 M, a first order is observed with respect to the reagents, while the order of the reaction with respect to H/sup +/ ions is equal to -3. The average value of the true rate constant of the reaction is k = 27.9+-1.3 M/sup 2/xmin/sup -1/ at ..mu..=2 and 39/sup 0/C. It was shown that with increasing analytical concentration of HNO/sub 3/ and NO/sub 3//sup -/ ions (in a mixture of HNO/sub 3/ +HClO/sub 4/), the value of K decreases. On the basis of an invetigation of the dependence of the reaction rate on the temperature in the interval 31-44.8/sup 0/, we calculated the values of the energy (E = 34.6 kcal/mole), enthalpy (..delta..H* = 34 kcal/mole), free energy (..delta..F* = 19.6 kcal/mole, entropy (..delta..S* = 49 entropy units) of activation of the reaction and the formal ionic entropy of the activated complex (PuOOHNp/sup 5 +/)*, S* = -87 entropy units. A reaction mechanism including an interaction of hydrolyzed neptunium and plutonium ions as the rate-determining step was proposed and discusses. The results obtained are compared with data for this reaction in perchloric acid wolution and for other similar redox reactions.}
journal = {Radiokhimiya; (USSR)}
volume = {18:2}
journal type = {AC}
place = {USSR}
year = {1976}
month = {Jan}
}