Multiscale characterization of ethanol–amino alcohol mixtures: thermophysical properties, hydrogen bonding, and in silico assessment for CO₂ capture

The properties of binary mixtures containing ethanol with three amino alcohols (ethanolamine, 2-butylethanolamine, and 2-anilinoethanol) were investigated through experimental measurements and computational methods. Density and ultrasonic velocity measurements were performed across the entire composition range at atmospheric pressure and temperatures from 293.15 K to 318.15 K. Various excess thermodynamic parameters, including excess molar volume, were derived from the experimental data. Quantum chemical calculations and molecular dynamics simulations were employed to elucidate the nature of intermolecular interactions, with particular attention to hydrogen bonding, and to investigate the structural and dynamic properties of the liquid mixtures at the molecular level. Additionally, COSMO-RS and molecular modeling techniques were used to explore the CO₂ absorption capacity of these mixtures in silico. The results revealed favorable interactions between CO₂ and the hydrogen-bonded solvent clusters, supporting their potential as non-aqueous CO₂ capture solvents. The combined experimental and theoretical insights provide a comprehensive understanding of the structural behavior and gas absorption performance of these hybrid solvents. • The study investigates binary mixtures of ethanol with three amino alcohols (ethanolamine, 2-butylethanolamine, and 2-anilinoethanol) using both experimental measurements and computational methods. • Experimental measurements of density and ultrasonic velocity were conducted across all composition ranges at atmospheric pressure and temperatures from 293.150 K to 318.150 K. • Excess thermodynamic parameters, including excess molar volume, were calculated from the experimental data to characterize the mixing behavior. • Quantum chemical calculations and molecular dynamics simulations were used to examine intermolecular interactions, with particular focus on hydrogen bonding networks. • The computational approach provided detailed insights into the molecular organization and dynamic behavior of these liquid mixtures, complementing experimental findings.