Calorimetric study on the decomposition of hydroxylamine in the presence of transition metals

Abstract

Hydroxylamine (HA), hydroxylamine chloride (HAC1), and hydroxylamine nitrate (HAN) were each mixed with aqueous solutions of Cr 3+, Cr 6+, Mn 7+, Co 2+, Co 3+, and Cu 2+, and their heat flow profiles were monitored by a small-scaled reaction calorimeter, SuperCRC. These mixing tests demonstrated that HA was less reactive than HACl and HAN with Mn 7+ and Cr 6+. Their UV–vis spectra confirmed that the substrates reacted when Mn 7+ and Cr 6+ were reduced. HA was more reactive with Cu 2+ than HAC1 and HAN and exhibited the highest reactivity among the three substrates with regard to metals in the intermediate oxidation states: Cr 3+, Co 3+, and Co 2+. During the reaction of HA and Co 3+, an induction period was observed. All exothermic reactions were accompanied by precipitation or a change in the UV–vis spectra.