The role of intermediate oxidation states of technetium in catalysis of the oxidation of hydrazine by oxo-anions. Part 2. Perchlorate ions

Abstract

The oxidation of hydrazine by an aqueous acid perchlorate medium is catalysed very efficiently by TcO₄ ^– ions in a manner recalling the nitrate ion system. The reaction shows an induction period followed by a fast stage of evolution of N₂, and a high turnover number (>60) but no residue of unreacted hydrazine is left in contrast to the nitrate system, especially under strongly acid conditions. The concentration of Tc^IV in the system goes through two maxima as reaction proceeds, the first being extremely sharp, the second much broader. This complex kinetic behaviour has been computer-modelled reasonably successfully. The colour changes depend on the acidity of the system, but some coloured products have been characterised by UV/VIS and/or ESR spectroscopy.