Kinetics of the reaction of CO2 with the sterically hindered amine 2-Amino-2-methylpropanol at 298 K

Absorption rates of CO2 into aqueous solutions of the sterically hindered amine AMP (2-amino-2-methylpropanol), under reaction-controlled conditions were measured. The experiments were carried out in a stirred vessel with a smooth horizontal interface. The results were interpreted in terms of the zwitterion mechanism for the reaction of CO2 with primary or secondary amines as originally proposed by Caplow (1968, J. Am. chem. Soc.90, 6795–6803) and Danckwerts (1979, Chem. Engng Sci.34, 443–446). The reaction rate constants and the equilibrium constant describing the stability of the carbamate of AMP were determined by fitting numerically calculated absorption rates to the experimentally observed ones. These constants were compared with data reported for AMP and with those for not sterically hindered amines. The relative values of the reaction rate constants could by explained only partially.