A pulse radiolytic study of the reaction hydroxyl + ozone in aqueous medium

Sehested, Κ.; Holcman, Jerzy; Bjergbakke, E.; Hart, Edwin J.

doi:10.1021/j150662a058

Cited by 84 publications

(37 citation statements)

References 5 publications

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“…The O 3 concentration in the O 3 /H 2 O 2 reservoir solution was measured immediately before and after each experiment. The decomposition of O 3 due to its reaction with H 2 O 2 was found to be negligible in the time scale of the experiment in accordance with the low rate constant for reaction (5), k 5 Յ 10 Ϫ2 M Ϫ1 s Ϫ1 [14,15].…”

Section: Reaction Of the Ferryl Ion With H 2 Osupporting

confidence: 62%

Activation parameters of ferryl ion reactions in aqueous acid solutions

Jacobsen¹,

Holcman²,

Sehested³

1997

Int. J. Chem. Kinet.

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Stock solution of ozone was prepared by bubbling the effluent from an Erwin Sander (V) ozonator through an aqueous HClO 4 solution. Ozone concentrations of (2.5Ϫ3.0) ϫ 10 Ϫ4 M were achieved without any special procedure. The ozone concentration was determined spectrophotometrically at its maximum absorption wavelength, max ϭ 260 nm, using an ApparatusFor the kinetic studies a Hi-Tech SF 51 Stopped-flow spectrophotometer (SFS) with UV and VIS lamps was used. This instrument has a mixing time of about 1 -2 ms, which enables us to measure rate constants in the range of 0.01 -700 s Ϫ1 . Both the ozone and ABSTRACT: The temperature dependence of the oxidation kinetics of Fe 2ϩ by O 3 at pH 0 -3 was studied by stopped-flow technique in the temperature range 5 -40°C. Activation parameters of the reactions involved in formation and decay of the ferryl ion (iron(IV)), FeO 2ϩ are determined. The reaction of Fe 2ϩ ϩ FeO 2ϩ was found to branch into two channels forming iron(III)-dimer, Fe(OH) 2 Fe 4ϩ , and Fe 3ϩ . The yield of the dimer, Fe(OH) 2 Fe 4ϩ , increases with temperature on the expense of the Fe 3ϩ yield. On the basis of the overall rate constant and relative yield of Fe(OH) 2 Fe 4ϩ the activation energy is determined for both channels. The activation parameters of the hydrolysis of the ferryl ion and its reaction with H 2 O 2 were also determined.

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Section: Reaction Of the Ferryl Ion With H 2 Osupporting

confidence: 62%

Activation parameters of ferryl ion reactions in aqueous acid solutions

Jacobsen¹,

Holcman²,

Sehested³

1997

Int. J. Chem. Kinet.

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“…The list, nonstandard, is principally based on the critical review of Elliot [14], completed by twenty or so contributions [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Within this comprehensive list, some crossed reactions or feed-back reactions hold the attention in consideration of their regulating role towards radiolysis.…”

Section: Reactionsmentioning

confidence: 99%

A comprehensive model to describe radiolytic processes in cement medium

Bouniol

Bjergbakke

2008

Journal of Nuclear Materials

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“…The

E^{TS}

was estimated by the Gaussian 09 Software and the k value of Reaction (R22) was calculated using Equation . Table shows the rate constant of Reaction (R22) in the gas and aqueous phases considering oxygen and hydrogen transfer in the transition state . Since both parallel paths occur simultaneously, the overall rate constant is the sum of the constants of each path.…”

Section: Reaction Kineticsmentioning

confidence: 99%

“…Chameides and Davis estimated a rate constant of 4 × 10 6 m 3 kmol −1 s −1 for the reaction based on a 1:40 ratio for reaction rates (O 3 +

{HO}_{2}^{.}

/ O 3 +

{HO}^{.}

), and Graedel et al used this rate constant in their model for droplet chemistry. Sehested et al reported the rate constant to be as low as 10 4 m 3 kmol −1 s −1 . However, the validity of these rate constants was questioned by later studies.…”

Section: Introductionmentioning

confidence: 99%

“…This finding suggests the potential existence of a number of other reactions that have not yet been considered in the mechanism. Oxygen‐hydrogen chemistry studies of aqueous phase atmospheric reactions, show that the reaction

O_{3} + {HO}_{2}^{.} \to {HO}_{}^{.} + 2 O_{2}

has the potential to solve this problem . Especially, in combination with the reaction

O_{3} + {HO}^{.} \Rightarrow {HO}_{2}^{.} + O_{2}

, this would create a chain reaction mechanism of ozone decomposition.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical estimation of the apparent rate constants for ozone decomposition in gas and aqueous phases using ab initio calculations

Esfahani

Visscher

2019

Can J Chem Eng

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An ab initio study, using the coupled cluster calculations (CCSD) method was conducted to investigate the kinetics of the ozone degradation in gas and aqueous phases considering the reaction of ozone with the hydroperoxyl radical. Two potential transition state paths, oxygen and hydrogen transfer, are studied and compared. It was revealed by the ab initio quantum chemical calculations that the calculated overall rate constant in the gas phase differs by approximately an order of magnitude from measured values. However, the calculated selectivity (branching fraction), which was measured directly with isotope studies of hydrogen atom transfer, is almost exactly equal to the experimental value at 298.15 K. The sensitivity analysis showed that adding the reaction between ozone and hydroperoxyl radical to the kinetic model accelerates the decomposition process by more than four times in the aqueous phase (pH = 7–8.5), and for an order of magnitude change in the rate constant of this reaction, the decomposition half‐life changes by 20–45 %. This result might affect our understanding of atmospheric ozone chemistry.

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A pulse radiolytic study of the reaction hydroxyl + ozone in aqueous medium

Cited by 84 publications

References 5 publications

Activation parameters of ferryl ion reactions in aqueous acid solutions

Activation parameters of ferryl ion reactions in aqueous acid solutions

A comprehensive model to describe radiolytic processes in cement medium

Theoretical estimation of the apparent rate constants for ozone decomposition in gas and aqueous phases using ab initio calculations

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