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The solubility constant of N2O in aqueous 1-dimethylamino-2-propanol (1DMA2P) solution in the concentration range of 0–3.0 mol/L was measured over the temperature range of 298–333 K, and the data used to fit existing models: Redlich-Kister, semi-empirical, and polynomial. A new model has also been developed to predict the solubility constant. Also, N2O diffusivity in aqueous 1DMA2P solution was measured over the concentration range of 0.5–2.0 mol/L and temperature range of 298–313 K. All models used fitted the solubility constant of N2O solubility in 1DMA2P solution data with absolute average deviations (ADDs) for the Redlich-Kister, semi-empirical, polynomial models and a new model of 12.2%, 8.1%, 0.2% and 2.2%, respectively. The data for N2O diffusivity in aqueous 1DMA2P solution were represented by the modified Stokes-Einstein and semi-empirical models (AADs of 2.3% and 13.6%, respectively). A new mechanism-based model was equally developed to better correlate experimental results and understand the process of diffusivity.

In this work, the CO2 equilibrium solubility in 1-dimethylamino-2-propanol (1DMA2P) solution was determined as a function of 1DMA2P concentration (over the range of 1–5 M), temperature (in the range of 298–333 K), and CO2 partial pressure (in the range of 8–101 kPa), and the data used to fit the correlations for K2 using Kent-Eisenberg, Austgen, Li-Sheng and Hu-Chakma models. A new K2 correlation model was also developed to predict the CO2 equilibrium solubility in 1DMA2P solution. It was found that all of the models could fit the CO2 equilibrium solubility in 1DMA2P solution data with absolute average deviations (ADDs) for the models by Kent-Eisenberg, Austgen, Li-Sheng, Hu-Chakma and Liu et al. of 14, 15, 12, 6.3 and 10%, respectively. In addition, the heat of CO2 absorption in 1DMA2P solution estimated using Gibbs-Helmholtz equation was found to be −31.67 kJ/mol. Information or guidelines about effective utilization of data of screened solvents is provided based on three absorption parameters, namely, CO2 equilibrium solubility, second order reaction constant, and CO2 absorption heat.

The CO 2 absorption performance of aqueous 1-(2-hydroxyethyl)pyrrolidine (1-(2-HE)PRLD) was studied with respect to kinetics (i.e., in terms of the pseudo-first-order rate constant ( k o ) and second-order reaction rate constant ( k 2 ), obtained using the stopped-flow apparatus). CO 2 equilibrium solubility and heat of CO 2 absorption were evaluated at the temperature range of 293–313 K in the 1-(2-HE)PRLD concentration range of 0.20–1.00 mol/L for kinetics and at 2 M for CO 2 solubility. The values of k o were then represented using the base-catalyzed hydration mechanism, which gave an acceptable AAD of 10%. In addition, Bronsted plots of k 2 vs. pKa were developed to predict k 2 using pKa values of various tertiary amines. In addition, the CO 2 equilibrium solubility and CO 2 absorption heat were obtained in this work. Based on a comparison with other amines such as MEA, MDEA and 1DMA2P, 1-(2-HE)PRLD showed better performance in terms of CO 2 equilibrium solubility (DEAB > 1-(2-HE)PRLD > 1-(2HE)PP > 1DMA2P > MDEA > MEA > DEA), kinetics (MEA > DEA > DEAB > 1-(2-HE)PRLD > 1-(2-HE)PP > DMMEA > 1DMA2P > MDEA.) and CO 2 absorption heat (MEA > DEA > MDEA > DEAB > 1-(2-HE)PRLD > 1-(2HE)PP > 1DMA2P). Therefore, 1-(2-HE)PRLD could be considered as a good alternative solvent for CO 2 capture. A correlation between kinetics and heat of CO 2 absorption has been developed to guide the design of what can be considered to be ideal amine solvents for CO 2 capture.