Correlating the physical solubility of CO₂ in several amines to the concentrations of amine groups

In this study, the physical solubilities of CO₂ in several amine solutions at different concentrations and pressures were determined using the nitrous oxide N₂O analogy. The solubilities of N₂O in four aqueous amine solutions, including Monoethanolamine (MEA), Diethanolamine (DEA), Diethylenetriamine (DETA), and Tetraethylenepentamine (TEPA) were determined experimentally at different concentrations and pressures ranging from 1 to 4 kmol/m³ and 101.3–405.3 kPa, respectively. The solubility of N₂O and CO₂ for a few amines were compared with data available in the literature. The experimental data agreed well with those published in the literature. The CO₂ solubility values obtained experimentally as well as other values from the literature were correlated to the concentrations of the amino groups in the amine. The physical solubility of CO₂ was found to be inversely proportional to the number of amino groups in the amine. The simple correlation can give reasonable predictions with an average error of less than 10% for CO₂ solubility at 298 K and 101.3 kPa.