Kinetics of Np(V) Reduction with Carbohydrazide Catalyzed by Tc(VII) in the Presence of U(VI)

Dvoeglazov, K. N.; Pavlyukevich, E. Yu.; Filimonova, E. D.; Alekseenko, V. N.

doi:10.1134/s1066362222020047

Cited by 2 publications

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“…17,19,21−23 Volk et al reported that carbohydrazide can quickly reduce Np(VI) to Np(V), while it further reduces Np(V) to Np(IV) very slowly. 17 23 These works suggest that the slow reduction of Np(V) to Np(IV) by carbohydrazide is probably the higher energy barrier, which is kinetically hindered. Although the reaction of Np(VI) to Np(V) by carbohydrazide was investigated experimentally, their mechanism is still unclear, so it is essential to explore the reaction mechanism of Np(VI) to Np(V) by CO(N 2 H 3 ) 2 from the perspective of theory.…”

Section: Introductionmentioning

confidence: 99%

“…Yan and his co-workers also studied the reduction reaction of Np(VI) and Np(V) by dihydroxyurea (DHU) using spectrophotometry and found that DHU can quite rapidly reduce Np(VI) to Np(V), while it very slowly reduces Np(V) to Np(IV) . Koltunov et al reported the kinetic and mechanistic studies on the reduction of Np(VI) by hydrazine and its derivatives, which directly reduces Np(VI) to Np(V) without further reduction to Np(IV) under suitably controlled conditions. ,, Recently, carbohydrazide (CO(N 2 H 3 ) 2 ), a derivative of hydrazine and urea, has received much attention because it can solely reduce Np(VI) to Np(V) in the extraction reprocessing of high-burn-up spent nuclear fuel. ,,− Volk et al reported that carbohydrazide can quickly reduce Np(VI) to Np(V), while it further reduces Np(V) to Np(IV) very slowly . Zavalina et al studied the reduction kinetics of Np(VI) by carbohydrazide in nitric acid solution and found that the reduction rate increases with increasing concentration of reductant and temperature .…”

Section: Introductionmentioning

confidence: 99%

“…Subsequently, Shilov et al further studied the reduction mechanisms of Np(VI) by carbohydrazide in perchloric acid solution and obtained activation energy with 86 ± 5 kJ mol –1 . Very recently, Dvoeglazov et al showed that the reaction rate of Np(V) reduction to Np(IV) by carbohydrazide is enhanced with increasing Tc(VII) ion concentration and temperature . These works suggest that the slow reduction of Np(V) to Np(IV) by carbohydrazide is probably the higher energy barrier, which is kinetically hindered.…”

Section: Introductionmentioning

confidence: 99%

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Insights into the Reduction Mechanisms of Np(VI) to Np(V) by Carbohydrazide

Wang

et al. 2023

J. Phys. Chem. A

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An efficient approach to Np separation in the Plutonium Uranium Reduction EXtraction (PUREX) process is to adjust Np(VI) to Np(V) by free-salt reductants, such as hydrazine and its derivatives. Recently, carbohydrazide (CO(N 2 H 3 ) 2 ), a derivative of hydrazine and urea, has received much attention, which can reduce Np(VI) to Np(V) in the extraction reprocessing of spent nuclear fuel. Herein, according to the experimental observations, we examine the reduction mechanism of four Np(VI) by one carbohydrazide molecule using multiple theoretical calculations. The fourth Np(VI) reduction with a 22.26 kcal mol −1 energy barrier is the rate-determining step, which is in accordance with the experimental observations (20.54 ± 1.20 kcal mol −1 ). The results of spin density reflect that the reduction of the first and third Np(VI) ion is an outer-sphere electron transfer, while that of the second and fourth Np(VI) ion is the hydrogen transfer. Localized molecular orbitals (LMOs) uncover that the breaking of the N−H bond and formation of the O yl −H bond are accompanied by the reaction from initial complexes (ICs) to intermediates (INTs). This work offers basic perspectives for the reduction mechanism of Np(VI) to Np(V) by CO(N 2 H 3 ) 2 , which is also expected to design excellent free-salt Np(VI) reductants for the separation of Np in the advanced PUREX process.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Insights into the Reduction Mechanisms of Np(VI) to Np(V) by Carbohydrazide

Wang

et al. 2023

J. Phys. Chem. A

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“…In Refs. [2]- [6] we considered the procedure of construction of the field operators ab initio (including for neutral particles). The Bogoliubov-Shirkov method has been used.…”

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Weyl and Majorana for Neutral Particles

Dvoeglazov

2023

J. Phys.: Conf. Ser.

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We compare various formalisms for neutral particles. It is found that they contain unexplained contradictions. Next, we investigate the spin-1/2 and spin-1 cases in different bases. Next, we look for relations with the Majorana-like field operator. We show explicitly incompatibility of the Majorana anzatzen with the Dirac-like field operators in both the original Majorana theory and its generalizations. Several explicit examples are presented for higher spins too. It seems that the calculations in the helicity basis only give mathematically and physically reasonable results.

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Kinetics of Np(V) Reduction with Carbohydrazide Catalyzed by Tc(VII) in the Presence of U(VI)

Cited by 2 publications

References 4 publications

Insights into the Reduction Mechanisms of Np(VI) to Np(V) by Carbohydrazide

Insights into the Reduction Mechanisms of Np(VI) to Np(V) by Carbohydrazide

Weyl and Majorana for Neutral Particles

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