Influence of 2-hydroxyethylammonium acetate-based protic ionic liquids on the thermophysical properties of aqueous DL-alanine solutions
摘要
Understanding the hydration behavior of amino acids is fundamental to gaining insights into protein solvation mechanisms. Within this framework, examining the solvation properties of amino acids in aqueous media containing protic ionic liquids (PILs) a novel class of environmentally friendly solvents is crucial for characterizing their hydration dynamics. This research focuses on the influence of ammonium-based PILs, specifically mono-, bis-, and tris-(2-hydroxyethyl) ammonium acetate, on the hydration characteristics of DL-alanine. By employing COSMO computational analysis alongside thermophysical property measurements, the study evaluates the hydration energies and σ-profiles of DL-alanine and the PILs. The thermophysical behavior of DL-alanine in aqueous solutions containing varying concentrations of protic ionic liquids (PILs) was systematically analyzed using experimental data and modeling approaches. The density, speed of sound, viscosity, and refractive index were measured for ternary solutions of DL-alanine, water, and PILs across a temperature range of (298.15 to 318.15) K under atmospheric pressure. The standard partial molar volume (