Absorption of carbon dioxide into diisopropanolamine solutions of polar organic solvents

The chemical absorption rate of carbon dioxide with diisopropanolamine (DIPA) was measured in such non-aqueous solvents as methanol, ethanol, n-propanol, n-butanol, ethylene glycol, propylene glycol, and propylene carbonate, and aqueous solvent at 298 K and 101.3 kPa using a semi-batch stirred tank with a planar of gas–liquid interface. The pseudo-first-order reaction rate constant obtained from the measured rate of absorption was used to obtain the elementary reaction rate constants in complicated reactions represented by zwitterion mechanism and the order of overall reaction of CO2 with amine. The enhancement factor of carbon dioxide at a low concentration of DIPA was obtained using the reaction rate constants obtained under the condition of a pseudo-first-order, fast reaction regime. Correlation between the elementary reaction rate constant and the solubility parameter of the solvent is presented.