The oxidation of ammonia in shock waves has been studied in the temperature range 2000–3000°K by following the appearance of OH and NH and the loss of NH3 spectrophotometrically. NH is shown to be unimportant in the oxidation and arises from the high-temperature decomposition of ammonia. The induction times for the appearance of OH and loss of NH3 are approximately identical. The following mechanism appears to explain the main features of the oxidation reaction : a non-branching chain sequence OH + NH3→ NH2+ H2O, NH2+ O2→ HNO + OH, with branching caused by the subsequent reaction of HNO, HNO → H + NO, HNO + O2→[NO + HO2]→ H + O2+ NO.
