Density, Speed of Sound, and Refractive Index of the Binary Solvent System <i>n</i> -Propanol + Monoethanolamine and Their Intermolecular Interactions

n-Propanol and monoethanolamine are widely used organic solvents and reaction media in the chemical industry. This work reports rigorous thermodynamic data, including density, speed of sound, and refractive index for the binary n-propanol + monoethanolamine system at 0.1 MPa and temperatures ranging from 293.15 to 318.15 K. Excess properties, such as excess molar volume, excess speed of sound, excess isentropic compressibility, and excess refractive index, were calculated to elucidate the system’s thermodynamic behavior and the nature of intermolecular interactions. Molecular dynamics simulations and quantum mechanical calculations combined with 1H NMR and IR spectra reveal that complex hydrogen bonding between the hydroxyl group of n-propanol and the amino/hydroxyl groups of monoethanolamine, coupled with van der Waals forces, drives significant nonideal behavior in the mixture. This study provides reliable thermodynamic data and theoretical insights for optimizing solvent formulations, chemical processes, and design strategies involving n-propanol and monoethanolamine, thereby facilitating technological advancements in related fields.