A novel hydroxylamine ionic liquid salt resulting from the stabilization of NH2OH by a SO3H-functionalized ionic liquid

A SO3 H-functionalized ionic liquid was used as an alternative to conventional inorganic acids in hydroxylamine stabilization, leading to the formation of a novel hydroxylamine ionic liquid salt that exhibits improved thermal stability and reactivity in the one-step, solvent-free synthesis of caprolactam in comparison with hydroxylamine hydrochloride and hydroxylamine sulfate.