- Oxidation of peroxynitrite by inorganic radicals: A pulse radiolysis study
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Reactivity of the peroxynitrite ion toward a number of inorganic radicals was determined by using the pulse radiolysis technique. The rate constants for the oxidation of the ONOO- ion by CO3·-, ·N3, and ClO2· radicals were determined from their decay kinetics to be (7.7 ± 1.2) x 106 (I = 0.6 M), (7.2 ± 0.9) x 108, and (3.2 ± 0.3) x 104 M-1 s-(l), respectively. For the ·OH radical, the rate constant of (4.8 ± 0.8) x 109 M-1 s-1 was obtained by using competition kinetic analysis. The oxidation potential of the ONOO- ion was estimated as 0.8 V from the kinetic data. Although thermodynamically favorable, oxidation of ONOO- by the °NO2 radical was not observed; an upper limit of 2.5 x 104 M-1 s-1 could be set for this reaction. Contribution from some of these reactions to the decomposition of peroxynitrite in the presence and absence of CO2 is discussed.
- Goldstein, Sara,Saha, Abhijit,Lymar, Sergei V.,Czapski, Gidon
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p. 5549 - 5554
(2007/10/03)
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- A Matrix-Isolation-Infrared Spectroscopic Study of the Reactions of Nitric Oxide with Oxygen and Ozone
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The oxidation of nitric oxide to NO2 has been studied by trapping the products of the gas-phase reactions of nitric oxide with excess oxygen and ozone in argon matrices at 10 K.The subsequent transitient species were identified and characterized by their infrared spectra.The primary products of the NO + O2 reactions were NO2, N2O3(A), N2O3(B), N2O4, and peroxy nitrate (OONO).The primary products of the NO + O3 reactions were NO2 and peroxy NO3 with the higher nitric oxides (N2O3, N2O4) formed in low concentrations relative to the NO + O2 reactions.Isotopic oxygen and ozone were employed to identify the infrared absorption frequency of peroxy nitrate.On the basis of our observations, reaction mechanisms are proposed for the oxidation of NO to NO2.
- Bhatia, Subhash C.,Hall, John H.
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p. 3255 - 3259
(2007/10/02)
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