- Reactions of Mn(II) and Mn(III) with alkyl, peroxyalkyl, and peroxyacyl radicals in water and acetic acid
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The kinetics of oxidation of Mn(II) with acylperoxyl and alkylperoxyl radicals were determined by laser flash photolysis utilizing a macrocyclic nickel complex as a kinetic probe. Radicals were generated photochemically from the appropriate ketones in the presence of molecular oxygen. In both acidic aqueous solutions and in 95% acetic acid, Mn(II) reacts with acylperoxyl radicals with k = (0.5-1.6) × 106 M-1 s-1 and somewhat more slowly with alkylperoxyl radicals, k = (0.5-5) x 10 5 M-1 s-1. Mn(III) rapidly oxidizes benzyl radicals, k = 2.3 × 108 M-1 s-1 (glacial acetic acid) and 3.7 × 108 M-1 s-1 (95% acetic acid). The value in 3.0 M aqueous perchloric acid is much smaller, 1× 107 M-1 s-1. The decarbonylation of benzoyl radicals in H2O has k = 1.2 × 106 s -1.
- Jee, Joo-Eun,Bakac, Andreja
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p. 2136 - 2141
(2010/07/05)
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- Kinetic Evidence for the Redox Cycling of Manganese(II,III) in the Presence of (1-)ON(NO)SO3(1-) in Aqueous Media
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Redox cycling of Mn(II/III) in the presence of (1-)ON(NO)SO3(1-) in the absence and presence of oxygen was studied by following the increase and decrease of Mn(III) spectrophotometrically as a function of , , and pH.The autoxidation reaction exhibits typical autocatalytic behaviour in which the induction period depends on the concentrations of M(III) and (1-)ON(NO)SO3(1-).Under acidic conditions the reaction does not take place in the absence of Mn(III) or O2.The concentrations of O2, Mn(II) and (1-)ON(NO)SO3(1-) determine whether only oxidation of Mn(II) to Mn(III), or reduction of Mn(III) to Mn(II), or both in one or two redox cycles is observed.Preliminary simulations of some of the observed kinetic traces are presented.
- Prinsloo, Frans F.,Pienaar, Jakobus J.,Eldik, Rudi van
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p. 293 - 300
(2007/10/02)
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