Study of Ion Speciation of CO₂ Absorption into Aqueous 1-Dimethylamino-2-propanol Solution Using the NMR Technique

In this work, the speciation (i.e., 1DMA2P molecule as well as 1DMA2PH⁺, HCO₃^-, and CO₃^2- ions) for the CO₂ reactive absorption of CO₂ in aqueous 1-dimethylamino-2-propanol solution (i.e., into a 1DMA2P-H₂O-CO₂ system) was studied using the ¹³C nulcear magnetic resonance (NMR) technique at a temperature of 301 K over the 1DMA2P concentration range of 0.5-2.0 mol/L and CO₂ loading range of 0-1.0 mol CO₂/mol amine. Also, in addition to other material conservation laws, a new criterion for selection of the protonation calibration curves, the charge balance of the 1DMA2P-H₂O-CO₂ system, was added in order to generate results with better accuracy. In addition, the equilibrium constants, K₁ and K₅, were also obtained using the NMR technique, which had good agreement with those from other works with absolute average deviations of 2.2% and 3.5%, respectively. (Chemical Equation Presented).