Chemical stabilities of secondary alkanolamine substrates in CO2 solvents under stripping conditions and generation pathways of thermal degradation products have been studied. The two products generated in each amine solution have been proven to be oxazolidone and timer of each amine The thermal degradation of secondary alkanolamine proceeds in two steps as consecutive reactions. The carbamate compound, which is CO2-absorbing amine, cyclodehydrates to generate oxazolidone, and the oxazolidone further reacts with another amine to generate dimer through decarbonation condensation.