Cerate oxidimetry: Electrolytic oxidation of cerium without use of a diaphragm cell

Smith, G. Frederick; Frank, G. T.; Kott, A. E.

doi:10.1021/ac50145a007

Cited by 21 publications

(8 citation statements)

References 2 publications

(2 reference statements)

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“…Therefore, cerium(IV) stability in a monophasic nitric acid phase was evaluated to ensure that it is not subject to reduction before extraction. Our results indicate that cerium(IV) is very stable in 4 M nitric acid for several days at 343 K and that no reduction process takes place under our conditions (Figure S2), in agreement with the reported literature . Since the distribution ratios decrease as a function of time, it actually appears that the extracted species, either Ce 2 O·6NO 3 ·3TBP (org) or Ce 4 O 4 ·8NO 3 ·6TBP (org) , are unstable.…”

Section: Resultssupporting

confidence: 92%

“…Our results indicate that cerium(IV) is very stable in 4 M nitric acid for several days at 343 K and that no reduction process takes place under our conditions (Figure S2), in agreement with the reported literature. 33 Since the distribution ratios decrease as a function of time, it actually appears that the extracted species, either Ce 2 O·6NO 3 ·3TBP (org) or Ce 4 O 4 ·8NO 3 ·6TBP (org) , are unstable. Therefore, the compound was synthesized by combining CAN with an excess of 2 equiv of TBP, and its reduction rate was studied spectrophotometrically in the dark at five different temperatures (287, 293, 298, 303, and 307 K).…”

Section: Resultsmentioning

confidence: 99%

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Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process

et al. 2019

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Modeling of plutonium(IV) behavior during an accidental fire in a reprocessing plant was considered using various non-radioactive metallic surrogates. Among those elements, cerium(IV) was supposed to be a suitable candidate due to possible formation of a complex with TPB, but its extractability and stability have not been studied previously under representative plutonium uranium reduction extraction (PUREX) conditions. In this work, we investigated the chemical analogy between cerium(IV) and plutonium(IV) in this extractive process and combustion thereof. Distribution ratios are reported for acidities of 1–4 mol L –1 in equal volumes of nitric acid and a 30:70 mixture of tributylphosphate and hydrogenated tetrapropylene. The influences of light, temperature, and extraction time were studied by UV–vis spectroscopy. The results showed that cerium(IV) is extracted quantitatively but is reduced over time to cerium(III) in the organic mixture. Spectrophotometric investigations of this reaction kinetics revealed an apparent rate constant k of 0.021 ± 0.002 mol 0.5 L 0.5 min –1 at 298 K and an apparent fractional reaction order of 0.5. The activation energy of this reduction was found to be around 82 ± 2 kJ mol –1 by the Arrhenius plot method. The combustion of mono- and biphasic solutions prepared with a cerium(IV) concentration of 10 g L –1 revealed that the extracted complexes, Ce 2 O·6NO 3 ·3TBP (org) or Ce 4 O 4 ·8NO 3 ·6TBP (org) , are reduced during the combustion. Compositions of the resulting ashes and soot were analyzed and highlighted the presence of pyrophosphates and polycyclic aromatic hydrocarbons, with some traces of cerium. Ce(IV) is not suitable to represent Pu(IV) from a chemical point of view in HNO 3 /TBP–HTP solutions.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process

et al. 2019

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“…The reaction of Ce H with H 202 [17] was chosen as a source for H0 2 radicals according to: [19]. The water used was either triple or single distilled (no difference in the spectra was observed when triple distilled water was replaced by single distilled water).…”

Section: Introductionmentioning

confidence: 99%

ESR Study of a Complex Formation Between HO₂ Radical and Peroxy‐Vanadium (V) Ion

Samuni

Czapski

1970

Israel Journal of Chemistry

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A8STRACTH0 2 radicals were generated in a flow system by the reaction: Ce 4+ +HP2-> Ce s+ + H0 2 +H+. The H0 2 radicals were mixed with V -HP2 solutions and ESR spectroscopy was used to follow the reaction. It was shown that H0 2 reacts with both VO(02)+ and VO(02}2 complexes. The ESR signal of the complexed radical consists of eight lines, indicating that the unpaired electron interacts with the Vanadium nucleus. The kinetics of the formation and decay reactions of the complexed radical were studied.

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“…Tetranitromethane was obtained from Fluka and before use it was washed and distilled as described by J. Rabani et al [18]. Ceric perchlorate was prepared by electrolytic oxidation of Ce(CI0 4 ) 3 in HCI0 4 1 M (19] and the acidity of its stock solution was kept very high (pH 0.3) in order to prevent the formation of a colloidal polymer [20].…”

Section: Introduction (I)mentioning

confidence: 99%

The Kinetics of Complexed and Free Ho₂ Radical in the Reaction of Ce⁺⁴ and H₂O₂

Czapski

Samuni

1969

Israel Journal of Chemistry

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The intermediates formed in the reaction of Ce+4 with H2O2 in 0.5 M perchloric acid were studied, spectrophotometrically and through the quenching method, using a stopped‐flow system. The spectrum in the UV range and the kinetics of the generated radicals and their dependence on Ce+3 concentration were investigated. On adding Ce+3 to the mixture, a change in the spectrum as well as in the recombination rate constant was observed. This behaviour was attributed to the formation of a complex between the cerous ion and the HO2 radical. The values of the recombination rate constant of the complexed radical is 4.0 ± 0.4·106 F−1 sec−1 while that of the free HO2 radical is 0.9 ± 0.1·106 F−1 sec−1. The stabilization constant of the complex was found to be 60 ± 18 F−1.

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Cerate oxidimetry: Electrolytic oxidation of cerium without use of a diaphragm cell

Cited by 21 publications

References 2 publications

Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process

Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process

ESR Study of a Complex Formation Between HO₂ Radical and Peroxy‐Vanadium (V) Ion

The Kinetics of Complexed and Free Ho₂ Radical in the Reaction of Ce⁺⁴ and H₂O₂

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Cerate oxidimetry: Electrolytic oxidation of cerium without use of a diaphragm cell

Cited by 21 publications

References 2 publications

Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process

Influence of Light and Temperature on the Extractability of Cerium(IV) as a Surrogate of Plutonium(IV) and its Effect on the Simulation of an Accidental Fire in the PUREX Process

ESR Study of a Complex Formation Between HO2 Radical and Peroxy‐Vanadium (V) Ion

The Kinetics of Complexed and Free Ho2 Radical in the Reaction of Ce+4 and H2O2

Contact Info

Product

Resources

About

ESR Study of a Complex Formation Between HO₂ Radical and Peroxy‐Vanadium (V) Ion

The Kinetics of Complexed and Free Ho₂ Radical in the Reaction of Ce⁺⁴ and H₂O₂