Kinetics of the Ce<sup>3+</sup>/BrO<sub>2</sub>-Reaction in Sulfuric Acid Medium

Försterling, Horst‐Dieter; Lamberz, H. J.; Schreiber, H.

doi:10.1515/zna-1985-0409

Cited by 4 publications

(3 citation statements)

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“…ClO 2 , it has never been isolated. It has been detected in matrices, by microwave, and UV/Vis spectroscopy, and it has been postulated as a central intermediate in the Belousov–Zhabotinsky oscillating reaction . We often observed violet solutions in our reactions, although always for only a short period of time.…”

Section: Methodsmentioning

confidence: 99%

Reactions of Bromine Fluoride Dioxide, BrO₂F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br₃O₄⁺ and Br₃O₆⁺

Seppelt

2019

Angew Chem Int Ed

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A reliable synthesis of unstable and highly reactive BrO2F is reported. This compound can be converted into BrO2+SbF6−, BrO2+AsF6−, and BrO2+AsF6−⋅2 BrO2F. The latter decomposes into mixed‐valent Br3O4⋅Br2+AsF6− with five‐, three‐, one‐, and zero‐valent bromine. BrO2+ H(SO3CF3)2− is formed with HSO3CF3. Excess BrO2F yields mixed‐valent Br3O6+OSO3CF3− with five‐ and three‐valent bromine. Reactions of BrO2F and MoF5 in SO2ClF or CH2ClF result in Cl2BrO6+Mo3O3F13−. The reaction of BrO2F with (CF3CO)2O and NO2 produces O2Br‐O‐CO‐CF3 and the known NO2+Br(ONO2)2−. All of these compounds are thermodynamically unstable.

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Section: Methodsmentioning

confidence: 99%

Reactions of Bromine Fluoride Dioxide, BrO₂F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br₃O₄⁺ and Br₃O₆⁺

Seppelt

2019

Angew Chem Int Ed

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“…Ce3+ + Br02 + H+ *± Ce4+ + HBr02 (R6) It must be pointed out that for reaction R6 only the forward rate constant k6 was obtained from a direct experiment. 5 The reverse rate constant k-t as given in ref 2, however, was deduced from indirect thermodynamic data only. The first investigators who followed (R-6) in a direct kinetic experiment (stopped flow technique) were Sullivan and Thompson.…”

Section: Chemicals and Experimental Methodsmentioning

confidence: 99%

Bromous acid/cerium(4+): reaction and HBrO2 disproportionation measured in sulfuric acid solution at different acidities

Foersterling¹

1993

J. Phys. Chem.

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The rate of the reaction of bromous acid with Ce4+, which is responsible for the slowing down of the autocatalytic oxidation of Ce3+ by bromate in the Belousov-Zhabotinsky reaction, is measured directly by spectroscopic methods in sulfuric acid medium at different acidities. Br02 radicals are identified as primary reaction products. The rate constant decreases from 40 000 M-' s1 in 0.3 M H2S04 to 1000 M-l s-l in 3 M HzS04. The reaction is slowed down upon the addition of NaC104. The observations are discussed on the assumption that the active cerium species are sulfato complexes with one or two sulfato groups; the equilibrium constants for the complex formation increase with increasing ionic strength leading to smaller concentrations of the active sulfatocomplexes. Additionally, the disproportionation reaction of HBrOz was investigated in the same range of acidities. The rate of this reaction increases from 1300 M-l s-l in 0.3 M HzS04 to 12 000 M-l s-l in 3.0 M HzS04. We suggest that the rate-determining step is a reaction of a protonated with an unprotonated HBr02. At high acidities the disproportionation reaction is fast enough to compete with the oxidation of HBrO2 by Ce4+. These results are important for the understanding of the autocatalytic process in the Belousov-Zhabotinsky reaction, especially at high sulfuric acid concentrations, and for the study of nonbromide controlled oscillations.

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“…ClO 2 konnte es bis heute nicht isoliert werden. Dieses konnte in Matrizen, durch Mikrowellen‐ und UV/Vis‐Spektren nachgewiesen werden, und es wurde als zentrales Zwischenprodukt der oszillierenden Beluosov‐Zhabotinsky‐Reaktion postuliert . Wir haben bei unseren Reaktionen oft eine violette Farbe beobachtet, aber immer nur für sehr kurze Zeit.…”

Section: Methodsunclassified

Reaktionen des Bromylfluorids, BrO₂F: Gemischtvalente Brom‐Sauerstoff‐Kationen, Br₃O₄⁺ und Br₃O₆⁺

Seppelt

2019

Angewandte Chemie

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Für das instabile und extrem reaktive BrO2F wird eine verlässliche Synthese beschrieben. Dieses wird in BrO2+ SbF6−, BrO2+ AsF6− und BrO2+ AsF6−⋅2 BrO2F umgewandelt. Letzteres zerfällt in Br3O4⋅Br2+ AsF6− mit fünf‐, drei‐ und einwertigem Brom. Mit HSO3CF3 bildet sich BrO2+H(SO3CF3)2−. Überschuss an BrO2F ergibt gemischtvalentes Br3O6+OSO3CF3− mit fünf‐ und dreiwertigem Brom. Reaktionen von BrO2F und MoF5 in SO2ClF oder CH2ClF ergeben Cl2BrO6+Mo3O3F13−. Die Reaktionen von BrO2F mit (CF3CO)2O und NO2 ergeben O2Br‐O‐CO‐CF3 und das bekannte NO2+Br(ONO2)2−. Alle diese Verbindungen sind thermodynamisch instabil.

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Kinetics of the Ce³⁺/BrO₂-Reaction in Sulfuric Acid Medium

Cited by 4 publications

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Reactions of Bromine Fluoride Dioxide, BrO₂F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br₃O₄⁺ and Br₃O₆⁺

Reactions of Bromine Fluoride Dioxide, BrO₂F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br₃O₄⁺ and Br₃O₆⁺

Bromous acid/cerium(4+): reaction and HBrO2 disproportionation measured in sulfuric acid solution at different acidities

Reaktionen des Bromylfluorids, BrO₂F: Gemischtvalente Brom‐Sauerstoff‐Kationen, Br₃O₄⁺ und Br₃O₆⁺

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Kinetics of the Ce3+/BrO2-Reaction in Sulfuric Acid Medium

Cited by 4 publications

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Reactions of Bromine Fluoride Dioxide, BrO2F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br3O4+ and Br3O6+

Reactions of Bromine Fluoride Dioxide, BrO2F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br3O4+ and Br3O6+

Bromous acid/cerium(4+): reaction and HBrO2 disproportionation measured in sulfuric acid solution at different acidities

Reaktionen des Bromylfluorids, BrO2F: Gemischtvalente Brom‐Sauerstoff‐Kationen, Br3O4+ und Br3O6+

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Kinetics of the Ce³⁺/BrO₂-Reaction in Sulfuric Acid Medium

Reactions of Bromine Fluoride Dioxide, BrO₂F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br₃O₄⁺ and Br₃O₆⁺

Reactions of Bromine Fluoride Dioxide, BrO₂F, for the Generation of the Mixed‐Valent Bromine Oxygen Cations Br₃O₄⁺ and Br₃O₆⁺

Reaktionen des Bromylfluorids, BrO₂F: Gemischtvalente Brom‐Sauerstoff‐Kationen, Br₃O₄⁺ und Br₃O₆⁺