Kinetics of Pu(VI) reduction with carbohydrazide in nitric acid

Zavalina, O. A.; Dvoeglazov, K. N.; Pavlyukevich, E. Yu.; Stepanov, S. I.

doi:10.1134/s1066362217040014

Cited by 3 publications

(1 citation statement)

References 6 publications

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“…The studies on the reduction of Pu(IV) have been explored in experiments using various reductants, including the combination of U(IV) with hydrazine − and salt-free reductants such as formo- and acetohydroxamic acid, − tert -butyl hydroquinone, − aldehydes, , hydroxylamines, − hydroxyurea, − hydrazine, − oximes, − and their derivatives. Of these, oxime derivatives reduce Pu(IV) to Pu(III) in HNO 3 solution with excellent stability, fast nitrous acid scavenging, and kinetics. ,− ,− Koltunov et al first reported the reduction of Pu(IV) by acetaldoxime in nitric acid and obtained the activation energy with the value of 87.7 ± 9.8 kJ mol –1 at 298 K .…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Reduction Mechanism of Pu(IV) by Acetaldoxime

Li,

Wu,

Wang

et al. 2023

J. Phys. Chem. A

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The separation of plutonium (Pu) from spent nuclear fuel was achieved by effectively adjusting the oxidation state of Pu from +IV to +III in the plutonium uranium reduction extraction (PUREX) process. Acetaldoxime (CH3CHNOH) as a free salt reductant can rapidly reduce Pu(IV), but the reduction mechanism remains indistinct. Herein, we explore the reduction mechanism of two Pu(IV) ions by one CH3CHNOH molecule, where the second Pu(IV) reduction is the rate-determining step with the energy barrier of 19.24 kcal mol–1, which is in line with the experimental activation energy (20.95 ± 2.34 kcal mol–1). Additionally, the results of structure and spin density analyses demonstrate that the first and second Pu(IV) reduction is attributed to hydrogen atom transfer and hydroxyl ligand transfer, respectively. Analysis of localized molecular orbitals unveils that the reduction process is accompanied by the breaking of the Pu–OOH bond and the formation of the OOH–H and C–OOH bonds. The reaction energies confirm that the reduction of Pu(IV) by acetaldoxime is both thermodynamically and kinetically accessible. In this work, we elucidate the reduction mechanism of Pu(IV) with CH3CHNOH, which provides a theoretical understanding of the rapid reduction of Pu(IV).

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