Thermal decomposition of hydroxylamine in aqueous solutions in the presence of NaCl, KCl or Na2SO4 in the temperature range 120 °C-140 °C

The thermal decomposition of hydroxylamine aqueous solutions in two different concentrations and three temperatures was studied in the presence of NaCl, KCl and Na2SO4 using isoperibolic calorimetry. The purpose of this study was to generate data for comparison of the thermal decomposition of different nitrogen containing compounds towards the ultimate, long-term goal to reveal the decomposition pathways of nitrogen containing species and to pinpoint the factors affecting these paths. It was found that Na2SO4 was substantially reducing hydroxylamine decomposition rate, while the other two inorganic salts had a non-measurable effect on hydroxylamine decomposition rate. When NaCl and Na2SO4 were used together the effect of the latter predominated. In all cases the non-condensable gas generation was not practically affected by the presence of any of the additives. The results were compared with the effect that KCl and Na2SO4 had on ammonium nitrate thermal-decomposition rate and similarities and differences are discussed. It is believed that rate deceleration effects of Na2SO4 are owing to the alkaline character of SO42− anion.