Diffusivity and Solubility of CO2 and N2O in Nonaqueous 2-(Ethylamino)ethanol/2-Hexyloxyethanol Solutions: Correlating Gas Properties with Solvent Polarity

Recent advancements have positioned nonaqueous amine-based absorbents as promising candidates for energy-efficient CO2 capture. However, detailed physicochemical data are still essential to support accurate modeling for scaling up the process. Diffusivity (D) and physical solubility (H) of N2O and CO2 in organic solvents were determined by using a stirred cell. Gas solubility ratios (HCO2/HN2O) in these solvents exhibit an inverse correlation with the solvents’ Hoy solubility parameters. Changes in the DCO2/DN2O ratio and D^(1/2)/H in various solvents are governed by interactions between gas properties and solvent polarity. Specifically in the 2-hexyloxyethanol (2-HE)/2-(ethylamino)ethanol system, DN2O was found to be inversely proportional to solvent viscosity with a power of 0.6. The ratios of the derived combined parameter D^(1/2)/H for CO2 and N2O increase with solvent polarity. This correlation framework allows reliable prediction of transport properties in the 2-HE based nonaqueous system, supporting kinetic study and scalable carbon capture design.