Kinetics and Mechanism of the Reaction Between Pentacyanonitrosylferrate(ii) and Hydroxylamine

The kinetics of the reaction between pentacyanonitrosylferrate(II) and hydroxylamine was studied spectrophotometrically and gas volumetrically in moderately alkaline media (pH = 8 −9.5). Reduction of the nitrosyl ligand takes place according to the following stoichiometry: The aquocomplex catalyses the following two disproportionation reactions of hydroxylamine: and Two paths for disproportionation were identified: a fast route, probably via radicals, initiated by a binuclear intermediate yielding N2 or N2O and a slower one through formation of Fe(CN)5NO4− as a stable intermediate yielding N2. A kinetic model was constructed which describes both the reduction of nitrosyl complex and the catalytic disproportionation reactions of hydroxylamine.