The investigation of the reaction mechanism of CO2 in HMDA/DEEA and EAE/1DMA2P aqueous solution systems

Revealing the reaction mechanism of CO 2 absorption by mixed amine solutions can provide theoretical guidance for establishing complex kinetic models. This study investigates the CO 2 capture mechanisms of blended amine systems, specifically 1,6-hexamethyl diamine (HMDA)-N,N-diethylethanolamine (DEEA) and 2-(ethylamino)ethanol(EAE)-1-dimethylamino-2-propanol (1DMA2P), utilizing 13 C nuclear magnetic resonance (NMR) spectroscopy and quantum mechanical calculations. The 13 C NMR analysis identified the formation and conversion of species during CO 2 absorption, while quantum calculations elucidated the reaction energetics. The results indicate that tertiary amines (DEEA or 1DMA2P) facilitate CO 2 absorption by promoting the desorption of protonated primary amines (HMDA or EAE), thereby enhancing the absorption rate. This research provides insights into the role of tertiary amines in blended systems, guiding the development of efficient and low-energy amine solvents for CO 2 capture. • The study revealed how blended amine systems enhance CO 2 absorption through synergistic interactions. • Tertiary amines accelerate CO 2 capture by facilitating primary amine deprotonation. • Findings guide the development of efficient, low-energy CO 2 capture solvents.