Nitrogen dioxide and related free radicals: electron-transfer reactions with organic compounds in solutions containing nitrite or nitrate

Abstract

The absolute rate constants for the reaction of NO₃^2–˙(formed by one-electron reduction of nitrate) with oxygen, benzoquinone, and methyl viologen have been determined by pulse radiolysis. Experiments have shown that such reactions can occur in competition with the hydrolysis reaction leading to NO₂˙ and that the formation of the latter can be catalysed by the presence of hydrogen or ammonium ions. Absolute rate constants for the oxidation of the phenothiazine derivative metiazinic acid, of 2,2′-azinobis-(3-ethyl-2,3-dihydrobenzothiazole-6-sulphonate), of ascorbate, and of dihydroxyfumarate by NO₂˙ have also been measured.