The dissociation constant of hydrogen peroxide and the electron affinity of the HO2 radical

Evans, M. G.; Uri, N.

doi:10.1039/tf9494500224

Cited by 164 publications

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“…Since H+ is not involved in the activated complex, the peroxide ion is presumably stabilized by interaction with the Fe +3 produced. If we use for each of the Fe+3-O~ interactions the value of the association constant reported (34) for Fe +s q-HO~-, AF ° for reaction (17) …”

Section: Reactions With Transition Metal Ionsmentioning

confidence: 99%

Mechanisms of Oxidation with Oxygen

Taube

1965

The Journal of General Physiology

138

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Several topics are dealt with in discussing the reactions of molecular oxygen, but a common goal is pursued in each: to try to understand the reactions in terms of the fundamental properties of the oxygen molecule, and of the other reactants. The paper first describes the electronic structure of oxygen and of two low-lying electronically excited states. Concern with the low-lying electronically excited states is no longer the sole property of spectroscopists; recently, evidence has been presented for the participation of such activated molecules in chemical reactions. The chemistry of oxygen is dominated by the fact that the molecule in the ground state has two unpaired electrons, whereas the products of oxidation in many important reactions have zero spin. In its reactions with transition metal ions the restrictions imposed by the spin state of the oxygen molecule are easily circumvented. A number of reactions of oxygen with metal ions have been studied in considerable detail; conclusions on basic aspects of the reaction mechanism are outlined. Among the most interesting reactions of oxygen are those in which it is reversibly absorbed by reducing agents. Reversible absorption to form a peroxide in the bound state is possible; some of the conditions which must be fulfilled by a reducing system to qualify as storing oxygen in this way are reasonably well understood and are here enunciated. Little has been done on the formation of oxygen from water; some factors involved in this process are discussed.

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Section: Reactions With Transition Metal Ionsmentioning

confidence: 99%

Mechanisms of Oxidation with Oxygen

Taube

1965

The Journal of General Physiology

138

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“…The H2O2/HO2 -pKa was calculated according to the results of Evans and Uri (1949) (Evans and Uri, 1949). The pH was computed by second or third degree polynomial functions fitted to the experimental values with determination coefficients R 2 higher than 99% (Example Fig.…”

Section: Eq 18 Only Depends On the Selected Operating Conditions (Tmentioning

confidence: 99%

“…This process is based on the fast ozone decomposition initiation reaction with the hydroperoxide anion (HO2 -). This anion is the H2O2 conjugated base (pKa ≈ 11.75 at 20°C (Evans and Uri, 1949)). …”

Section: Introductionmentioning

confidence: 99%

Determination by reactive absorption of the rate constant of the ozone reaction with the hydroperoxide anion

Biard

Dang

Couvert

2017

Chemical Engineering Research and Design

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International audienceThe reaction rate constant between the hydroperoxide anion (HO2−) and molecular ozone was evaluated from the reactive absorption method in the range of temperature from 20 to 35 °C. This reaction is crucial in the initiation step of the ozone decomposition, especially using the peroxone process which combines ozone and hydrogen peroxide in solution. A stirred-cell operated semi-continuously was used for this purpose. A high initial concentration of tert-butanol (0.05 mol L−1) was applied to efficiently scavenge all radicals and to avoid any parasite reaction. Based on the dissolved H2O2 concentration decreasing and the outlet ozone concentration time-course, the stoichiometry of the initiation reaction was determined, with one mol of H2O2 consumed per mol of ozone transferred. The chemical conditions were thoroughly selected to reach a fast pseudo-first order absorption regime. The reaction rate constant increased from 1.91 × 106–2.40 × 106 L mol−1 s−1 at 20 °C to 5.68 × 106–7.31 × 106 L mol−1 s−1 at 35 °C

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“…However, we were unable to find any reported values for the corresponding dissociation constant of D202. Therefore, we used the kinetic data to determine K, by performing a fit to expression [6] with K, as an extra adjustable parameter.By processing the D202 data in this manner we have determined K, to be 6.8(6) x 10-l3 M (pK, = 12.2(2)) at 25°C. (For H202 pK, = 11.66 at this temperature (4).)…”

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confidence: 99%

Determination of the dissociation constant of D₂O₂ in D₂O by a conventional method and via muonium kinetics

Brodovitch¹,

Percival²,

Poteryko³

1988

Can. J. Chem.

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POTERYKO. Can. J. Chem. 66, 2410 (1988. The dissociation constant of deuterium peroxide has been determined from measurements of the pH of mixtures of D202/NaOD in D20. At 2S°C, pK, = 12.35 (S), confirming the value previously deduced from a kinetic study of the reactions of muonium with H202 and Dz02. The enthalpy and entropy of dissociation of D20z are estimated to be 34.7 (8.8) kl mol-I and -120 (30) J K-', respectively. We have recently completed an extensive study of the kinetics of the reactions Mu + H202 and Mu + D202 in aqueous solution. Muonium (Mu) is the exotic atomic system p+e-, and behaves as a light radioactive isotope of H (see ref. 1 for a general introduction and references to the literature of Mu chemistry and the pSR technique). Muonium decay rates were measured for various conditions of peroxide concentration (0 to 3 mM), acidity of the medium (pH 3 to pH 12.4 for H202, pD 3 to pD 13.7 for D202) and temperature (0 to 50°C). A preliminary account and most of the data are to be found in a conference report (2). Full experimental details and interpretation of the results in terms of mechanism and isotope effects will be reported in a full publication elsewhere. This short note is intended to highlight a "spin-off" of the kinetics study, namely, the determination of the ionisation constant of D202, and to report an independent determination by more conventional means. JEAN-CLAUDE BRODOVITCHThe H202 data are consistent with the following reaction scheme:Mu + OH--products For such a scheme, the first order decay rate for the disappearance of Mu is given by (1): where [H2O2It = [H202] + [H02-] is the nominal peroxide concentration, and A. is the decay rate measured for pure water. A similar reaction scheme and an analogous expression to [6] was assumed for the Mu + D202 system. The purpose of the kinetics study was to determine k, and k2 and their equivalents in the D202 scheme. They may be obtained by fitting [6] to the experimental data, using kl , k2, and k3 as adjustable parameters. In the case of the H202 system we used literature values of K, (3). However, we were unable to find any reported values for the corresponding dissociation constant of D202. Therefore, we used the kinetic data to determine K, by performing a fit to expression [6] with K, as an extra adjustable parameter.By processing the D202 data in this manner we have determined K, to be 6.8(6) x 10-l3 M (pK, = 12.2(2)) at 25°C. (For H202 pK, = 11.66 at this temperature (4).) However, to obtain meaningful fits some constraints had to be imposed on K, during the calculations. Specifically, the variation of pK, with temperature was required to be equal for H202 and D202, in similar fashion to the temperature dependence of pK, for H 2 0 and D20. In terms of the activation parameters for the dissociation of D202, this is equivalent to imposing the same AH" value as that of H202 while leaving AS' a free parameter. The pK, value found for D202 is larger than that of H202, which seems reasonable given the relative dissociation constan...

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The dissociation constant of hydrogen peroxide and the electron affinity of the HO2 radical

Cited by 164 publications

References 0 publications

Mechanisms of Oxidation with Oxygen

Mechanisms of Oxidation with Oxygen

Determination by reactive absorption of the rate constant of the ozone reaction with the hydroperoxide anion

Determination of the dissociation constant of D₂O₂ in D₂O by a conventional method and via muonium kinetics

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The dissociation constant of hydrogen peroxide and the electron affinity of the HO2 radical

Cited by 164 publications

References 0 publications

Mechanisms of Oxidation with Oxygen

Mechanisms of Oxidation with Oxygen

Determination by reactive absorption of the rate constant of the ozone reaction with the hydroperoxide anion

Determination of the dissociation constant of D2O2 in D2O by a conventional method and via muonium kinetics

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Determination of the dissociation constant of D₂O₂ in D₂O by a conventional method and via muonium kinetics