Mécanisme des réactions du chlorite et du dioxyde de chlore. 3. La dismutation du chlorite

Schmitz, Guy; Rooze, Henri

doi:10.1139/v85-162

Cited by 16 publications

(13 citation statements)

References 14 publications

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“…The net effect of reactions 6, 6′, 7, 7′, and 9 accounts for the unusual chloride ion dependence of the initial rate of decomposition. Our value of k 9 ) 0.00343 M -2 s -1 lies within the previously reported range, which includes determinations of 0.000483, 6 0.0018, 7 and 0.014 5 M -2 s -1 .…”

Section: Discussionsupporting

confidence: 90%

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Kinetics and Mechanism of the Decomposition of Chlorous Acid

et al. 2003

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The kinetics of decomposition of aqueous chlorous acid has been reinvestigated at pH 0.7-1.9, ionic strength 1.0 M (HSO 4 -/SO 4 2-), and temperature 25.0 ( 0.1°C. Optical absorbances were collected in the 240-450 nm wavelength range for up to ∼90% decomposition for time series lasting as long as 2 days. The number of absorbing species was investigated by matrix rank analysis; no absorbing intermediate was formed in significant concentration during the decomposition. Of the many mechanistic models tested, the one that fit best included the following reactive intermediates: HOCl, explains the variation in stoichiometric ratio as well as the maximum observed in the initial rate of ClO 2 formation as a function of pH. The kinetics of chlorous acid decomposition cannot be quantitatively fit through the last stages of the reaction without postulating a first-order decomposition. Scission of chlorous acid to give short-lived hydroxyl and chlorine-(II) monoxide is a plausible route for this process. A set of best-fit and literature-derived parameters is presented for the complete mechanism.

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Section: Discussionsupporting

confidence: 90%

“…Stoichiometry. Several groups of investigators [5][6][7] have found that in the absence of chloride ion the stoichiometry of the decomposition of chlorous acid is given by reaction A:…”

Section: Resultsmentioning

confidence: 99%

Kinetics and Mechanism of the Decomposition of Chlorous Acid

et al. 2003

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“…At neutral and mildly acidic pH, the rate law resembles that of Br(III), with an [H+]-dependent term second-order in C1(III).22 At lower pH, two additional terms appear in the rate law, because HClOz becomes capable of oxidizing C1-to HOCl, giving rise to C1catalysis. 21 The comparable process does not occur for HBr02 in the pH range we have studied, and a similar B r catalysis is not observed. Lastly, an iron-catalyzed radical chain mechanism has been reportedz0 and interpreted as evidence of reversible oneelectron oxidation of ClOz-to C102 by Fe3+; a similar effect has not been observed in the Br(II1) system.…”

Section: Discussionmentioning

confidence: 63%

Kinetics of Disproportionation and pKa of Bromous Acid

Faria¹,

Epstein²,

Kustin³

1994

J. Phys. Chem.

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The kinetics of the disproportionation reaction of bromine(III), 2Br(III) -Br(1) + Br(V), was studied in phosphate buffer, in the pH range 5.9-8.0, by monitoring optical absorbance at 294 nm using stopped-flow,The dependences on C?H+ and [Br(III)] were of order 1 and 2, respectivley, and no dependence on [Br-] was found. The reaction was also studied in acetate buffer, in the pH range 3.9-5.6. Within experimental error, no evidence was found for a direct reaction between two BrO2-ions. This study yields rate constants 39.1 f 2.6 M-I s-l for the reaction HBrO2 + BrO2--HOBr + Br03-and 800 f 100 M-' for the reaction 2HBr02 -HOBr + Br03-+ H + and an equilibrium quotient for HBr02 e H + + BrOz-of 3.7 f 0.9 X 10-4 M (pKa = 3.43) at ionic strength 0.06 M and 25.0 f 0.1 OC. The bromous acid dissociation constant is essentially identical to the value previously obtained from a kinetics study of the bromine(II1)-I-reaction (J. Phys. Chem. 1992, 96, 6861).

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“…As a consequence, the reaction kinetics will be expected to be different. Also, the impurity effect due to the presence of some transition-metal ions, such as iron, on the disproportionation of chlorous acid, which has been well-documented (Schmitz and Rooze, 1985), may be partly responsible for the difference between these studies.…”

Section: Resultsmentioning

confidence: 95%

Disproportionation of Chlorous Acid at a Strong Acidity

Yin

1998

Ind. Eng. Chem. Res.

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Commercial chlorine dioxide generators are operated in an about 4.5-mol/L sulfuric acid solution. The chlorous acid disproportionation may be an important pathway to generate chlorine dioxide under such a condition. On the basis of the product determination, we found that, in the absence of a chloride ion, chloric acid, hypochlorous acid, and chlorine, rather than chlorine dioxide, are the products from the chlorous acid disproportionation. However, chloride addition to the chlorous acid solution under otherwise the same condition results in the generation of chlorine dioxide. The underlying mechanism of the chloride effect on the chlorous acid disproportionation is discussed.

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Mécanisme des réactions du chlorite et du dioxyde de chlore. 3. La dismutation du chlorite

Cited by 16 publications

References 14 publications

Kinetics and Mechanism of the Decomposition of Chlorous Acid

Kinetics and Mechanism of the Decomposition of Chlorous Acid

Kinetics of Disproportionation and pKa of Bromous Acid

Disproportionation of Chlorous Acid at a Strong Acidity

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