Reaction Pathways of Hydroxylamine and Ammonia Oxide

Hydroxylamine (NH2OH) is an unstable compound at room temperature, and has been involved in two tragic incidents in the chemical industry. Ammonia oxide (NH3O), the zwitterionic tautomer of hydroxylamine, has been reported for its existence in the condensed phase which provides the important evidence relevant to the exceptional reactivity of hydroxylamine (J. Am. Chem. Soc. 2006, 128, 12374). In this work, the molecular structures and reactivity of hydroxylamine and ammonia oxide were explored using the Gaussian 03 suite of programs. The various reaction pathways of hydroxylamine and ammonia oxide were investigated with density functional and ab initio calculations. The transition state for each pathway was identified and analyzed, and the activation energy was calculated. This work shows ammonia oxide is the most important intermediate during the decomposition of hydroxylamine and is present in substantial amounts in aqueous solutions of hydroxylamine, which are consistent with current research results (Chem. Commun. 2010, 46, 1302).