Kinetics of Absorption of Carbon Dioxide into Aqueous 2-Amino-2-ethyl-1,3-propanediol Solutions

Abstract

Chemical reaction kinetics of CO2 with a sterically hindered amine, 2-amino-2-ethyl-1,3-propanediol (AEPD), in aqueous solutions has been studied by a wetted-wall column absorber. Three reaction temperatures of 305.15, 313.15, and 318.15 K and AEPD concentration ranges from 5 to 25 wt % APED were chosen. Specific absorption rates as a function of CO2 partial pressure in aqueous AEPD solutions were measured as well. The N2O analogy was applied to estimate the physicochemical properties of CO2 in amine solutions. Based on the zwitterion mechanism, the zwitterion deprotonation and second-order rate constants were calculated and presented at each temperature. The second-order rate constants, k2, were found to be 378, 855, and 1278 m3·kmol-1·s-1 at 303.15, 313.15, and 318.15 K, respectively.