Experimental study of the kinetics of the homogenous reaction of CO₂ into a novel aqueous 3-diethylamino-1,2-propanediol solution using the stopped-flow technique

In this work, the stopped-flow technique was used to determine the kinetic parameters in terms of pseudo first-order rate constants (k₀) for homogenous reaction of CO₂ into aqueous 3-diethylamino-1,2-propanediol (DEA-1,2-PD) solutions as temperature ranged from 293 to 313K and amine concentrations ranged from 0.20kmol/m³ to 1.00kmol/m³. It was found that k₀ increased with increasing amine concentration and temperature. Both the base-catalyzed hydration and the termolecular models were applied to interpret the experimental data. The results showed that the predicted CO₂ absorption rates exhibited good agreement with experimental data with an absolute average deviation (AAD) of 5.7% and 3.8% with respect to base-catalyzed hydration and the termolecular model, respectively. Furthermore, the pKa of DEA-1,2-PD was experimentally determined over the temperature range from 298 to 318K. The relationship between experimentally measured second-order reaction rate constants (k₂) and pKa was correlated using the Brønsted relationship. The results suggest that the Brønsted relationship for DEA-1,2-PD developed in this work can predict the reaction rate constant very well with an AAD of 0.8%.