Thermal decay of TEMPO in acidic media via an N-oxoammonium salt intermediate

Disproportionation of TEMPO in acids leads to the formation of an N-oxoammonium salt, which can further decompose under thermal conditions, yielding the corresponding hydroxylamine, N(2)O, CO(2) and a series of dimerisation products. Overall, acid-catalysed thermal decay of TEMPO leads to ca. 80% yield of hydroxylamine.