Study of solvation consequences of α-amino acids in aqueous ionic liquid solution probed by physicochemical approach

• l-Valine is more associated in aqueous Bu4PBF4 solution than the other amino acids.
• Solute–solvent interaction predominates over the solute–solute interactions in all the studied solutions.
• The overall order of solute–solvent interaction is found to be glycine < l-alanine < l-valine.

The apparent molar volume (ϕV), viscosity B-coefficient, molal refraction (R) and adiabatic compressibility (ϕK) of glycine, l-alanine, and l-valine have been studied in 0.001, 0.003, 0.005 mol dm−3 aqueous tetrabutylphosphonium Tetrafluoroborate (Bu4PBF4) solutions at 298.15 K from the values of density (ρ), viscosity (η), refractive index (nD) and speed of sound (u  ) respectively. The limiting apparent molar volumes (ϕV0), experimental slopes (SV*) are obtained from the Masson equation and have been interpreted in terms of solute–solvent and solute–solute interactions respectively. Jones–Dole equation were employed to analyze the viscosity data and the interpretation of the derived parameters A and B have also been carried out in terms of solute-solute and solute–solvent interactions in the solutions respectively. Molal refractions (R  ) have been determined with the help of Lorentz–Lorenz equation. Limiting apparent molar adiabatic compressibilities (ϕK0) of three amino acids at infinite dilution were evaluated and discussed.