This study examines oxidative degradation of 12 ethanolamines and ethylenediamines. They were chosen to establish structure-property relationships: the role of replacement of the alcohol function by one second amine function, amine nature, steric hindrance, and cyclic structure were studied. Degradation of aqueous amine solutions was evaluated at 140 degrees C under air pressure (2 MPa) in stainless steel reactors for 15 days. At the end of the run, most degradation products were identified by gas chromatography (GC)/mass spectrometry (MS); amounts of remaining amine and its degradation products were determined with the quantitative GC method. Main degradation mechanisms are proposed, and some relationships between structure and chemical stability are given.