No abstract

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 °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.

Degradation of 12 different amines with CO2 was evaluated in 100 mL stainless steel batch reactors for 15 days at 140 °C using a 4 mol·kg−1 amine solution and a CO2 pressure of 2 MPa. At the end of the run, most of degradation products were identified by gas chromatography (GC)/mass spectrometry (MS); amounts of starting amine and its degradation products were determined with a quantitative GC method. This work compares the degradation of ethanolamines (including MEA) having one or two hydroxyl groups with the degradation of ethylenediamines. They were chosen to establish relationships between amine structure and stability properties: replacement of one alcohol function by one amine function, effect of amine function nature, impact of steric hindrance and cyclic structure. Significant differences were observed. The main degradation products are described, and some mechanisms are proposed to explain their formation.