The oxidation of hydroxylamine by nitric and nitrous acids in the presence of technetium (VII)
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V. S. Koltunov
The oxidation of hydroxylamine by nitric acid in the presence of technetium ions at temperatures above ~60°C is an autocatalytic process comprising an induction period and then a catalysed reaction involving HNO2, which has accumulated in the solution. Tc ions have no appreciable effect on the reaction rate, which is governed only by the nitric and nitrous acid oxidation reactions of hydroxylamine, but the presence of Tc ions does extend the initial induction period. The rate of hydroxylamine oxidation by HNO3 in the presence of HNO2, that is, after the induction period, was found to be:
-d[NH3OH+]/dt = k[NH3OH+][HNO2][HNO3]3.5
where k = 120±10 l4.5 mol-4.5 min-1 at T = 80°C, μ = 2 and [H+] ≤ 2 M. Under these conditions, the reaction apparently has a high activation energy of 160-180 kJ mol-1. At low temperatures (20-40°C) hydroxylamine is effectively stable in solutions of HNO3 up to concentrations of ~2 M, whether or not Tc(VII) ions are present. Tc(V) was also observed to form at least one complex on reduction with excess hydroxylamine with an absorption maximum between 467 and 480 nm dependent on the solution acidity.
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Artikel in diesem Heft
- Recoil properties of radionuclides formed in photospallation reactions on complex nuclei at intermediate energies
- Understanding the peak asymmetry in alpha liquid scintillation with β/γ discrimination
- A device for on-line electromigration measurements of radioelements in free electrolytes
- Mixed-ligand chelate extraction of thorium(IV) and uranium(VI) with thenoyltrifluroacetone and various imidazoles
- The hydrolysis of dioxouranium(VI) investigated using EXAFS and 17O-NMR
- Interaction of europium with humic acid covalently bound to silica beads
- The oxidation of hydroxylamine by nitric and nitrous acids in the presence of technetium (VII)
- Separation of 187,188Pt and 187,188Ir produced in 11B4+ irradiated tantalum target
