Kinetics of the neptunium(IV)--plutonium(VI) and the neptunium(IV)--neptunium(VI) reactions in aqueous perchlorate solutions. [At 30 to 45/sup 0/C; effects of sulfate]
The oxidation of Np(IV) by Pu(VI) was studied at four temperatures from 30 to 45/sup 0/C in 1 M (H,Li)ClO/sub 4/ solutions with (H/sup +/) between 0.04 and 0.6 M. Calculations were made to allow for the complications due to further reaction of Pu(V) and other products. The rate law for the predominant reaction is -d(Np(IV))/dt = k(Np/sup 4 +/)(PuO/sub 2//sup 2 +/), where k depends on (H/sup +/): k = a(H/sup +/)/sup -2/ + b(H/sup +/)/sup -3/ or, alternatively, k/sup -1/ = (c(H/sup +/)/sup -2/)/sup -1/ + (d(H/sup +/)/sup -3/)/sup -1/. ..delta..H* values associated with a,b,c, and d are 31.1 +- 0.9, 40.1 +- 2.0, 33.5 +- 0.8, and 37.3 +- 2.5 kcal/mol, respectively. The corresponding ..delta..S* values are 30 +- 3, 53 +- 6, 39 +- 3, and 50 +- 8 cal/(mol deg). Sulfate was found to inhibit the reaction. The oxidation of Np(IV) by Np(VI) was studied at 25 and 35/sup 0/C in 1 M (H,Li)ClO/sub 4/ solutions with (H/sup +/) between 0.04 and 0.5 M. Except for the details of the hydrogen ion dependence the results were in agreement with the previous work of Hindman et al.
- Research Organization:
- Los Alamos Scientific Lab., NM
- OSTI ID:
- 7124833
- Journal Information:
- Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 15:11; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPOUNDS
CHARGED PARTICLES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
HALOGEN COMPOUNDS
HYDROGEN IONS
IONS
KINETICS
MEDIUM TEMPERATURE
NEPTUNIUM COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PERCHLORATES
PLUTONIUM COMPOUNDS
REACTION KINETICS
REDUCTION
SULFATES
SULFUR COMPOUNDS
TRANSURANIUM COMPOUNDS