Reaction kinetics of carbon dioxide with potassium prolinate in water-lean solvents

Water-lean absorbents have potential applications for energy-efficient CO 2 capture. In this work, the chemical kinetics of the reaction between carbon dioxide (CO 2 ) and potassium prolinate (ProK) in ethanol, ethylene glycol and water solvents was measured in a stirred cell reactor with a stable gas-liquid interface at temperatures from 275.2 to 285.2 K and ProK molar concentrations up to 2.0 M. The experiments were performed under the pseudo-first-order regime to determine the overall kinetic rate constant ( k ov ) using two-film theory. The results showed that the reaction rates in each polar solvent increase considerably as the increasing ProK concentrations and temperatures. The reaction order was found to be in the range of 1.4–2.0 with respect to ProK concentration, depending on the solvents used. The kinetic results for the reaction in ethanol were also interpreted based on zwitterion mechanism and termolecular mechanism. The calculated from the two proposed models match well with the experimental data.