Characterization of MIPA and DIPA aqueous solutions in relation to absorption, speciation and degradation

•Both solutes causes a reduction in mass transfer coefficient due to viscosity.•The production of carbamate and bicarbonate was observed for both amines.•The degradation rate for all amines is low. The carbon dioxide absorption process by 1-amino-2-propanol (MIPA) and bis(2-hydroxypropyl)amine (DIPA) aqueous solutions in bubble column reactor have been studied considering the influence of liquid phase physical properties and the amine group substitution on the overall process. The main objective of this work was to establish the carbon dioxide capture reaction mechanism for these systems, and then to obtain the predominant stoichiometry to calculate the mass transfer coefficient. NMR technique was used to determine the species present in the liquid phase during the absorption process and to confirm the reaction mechanism. The degradation of these amines was also evaluated.