THE OXIDATION OF HYDROXYLAMINE BY NITRIC-ACID IN THE PRESENCE OF TECHNETIUM(VII)

The reaction between hydroxylamine and nitric acid in the presence of pertechnetate ions has been studied. Sulphamic acid has been used to r emove any nitrous acid formed during the course of the reaction which would otherwise dominate the rate of oxidation. The reaction was shown to have an induction period and then accelerate. Although the reactio n mechanism could not be determined, the rate of reaction could be con veniently described by: - d[NH3OH+]/dt = k(1)[NH3OH+] + K-2[NH3OH+]([N H3OH+](0)-[NH3OH+]') [Tc(VII)] [HNO3](3). The rate constants for the t wo routes of this reaction were found to be k(1) = (2.8+/-0.4) x 10(-4 ) min(-1) and k(2) = 2.7+/-0.3 l(5) mol(-5) min(-1) at 80 degrees C an d an ionic strength of 2. The activation energy for the accelerated or autocatalytic reaction route (E-2) was determined to be 60+/-3 kJ mol (-1). k(1) however varied insignificantly with temperature with E-1 ap proximately equal to 15+/-4 kJ mol(-1).