CO2 capture studies in DETA-1DMA2P biphasic solvent system – experimental and quantum-chemical insights

In this study, a novel mixed amine biphasic absorbent composed of DETA, 1DMA2P, and H 2 O was constructed for CO 2 capture. Physical properties of the biphasic absorbent were calculated over the temperature range of 298.15 K to 313.15 K, while its CO 2 absorption kinetics were investigated in a stirred tank reactor. Based on different reaction mechanisms of the primary amine DETA and the tertiary amine 1DMA2P with CO 2 , the overall reaction rate constant (k ov ) and the second-order reaction rate constant (k 2 ) of the biphasic solvent were calculated. Using Arrhenius equation, the activation energies of DETA and 1DMA2P solutions in the biphasic absorbent were calculated to be 19.37 kJ/mol and 51.45 kJ/mol, respectively, both lower than those of pure solutions. 13 C NMR data and quantum chemical calculations indicate the generation of highly polar products with increasing CO 2 flow rate, prompting the phase transition in homogeneous solution. DETA and its products dissolved in aqueous phase form the CO 2 -rich phase. The less polar 1DMA2P interacted less strongly with DETA products and separated into upper layer of the solution due to its lower density than the DETA-related products.