Effect of Ionic Liquid Choline Lactate on Thermodynamic and Transport Properties of Amino Acids Glycine, l-Alanine, and l-Phenylalanine

Abstract

The use of hazardous and unstable solvents in various industries, particularly those involved in pharmaceuticals and chemicals, leads to significant environmental issues. Ionic liquids (ILs), a novel class of solvents, are often categorized as ″green solvents″ due to their low vapor pressure. Among them, choline-based ILs exhibit a low toxicity and high biodegradability. This study aims to synthesize and characterize ionic liquid choline lactate ([Ch][La]) using 1 H-NMR and FT-IR spectroscopy and examining solute−solvent interactions based on measured thermophysical properties of the amino acids glycine, L-alanine, and Lphenylalanine in the presence of the IL. The density, speed of sound, viscosity, and electrical conductivity data are measured for obtaining volumetric, acoustic, and transport properties at 298.15 K. By utilizing Masson, Jones−Dole, and lcCM equations, various thermodynamic properties such as partial molar volume V φ 0 , partial molar isentropic compressibility κ φ 0 , viscosity B-coefficient, limiting molar conductivity Λ 0 , and ion association constant K A have been computed. The ion−ion interaction and ion−hydrophilic interaction between the ionic liquid and amino acid dominate with increasing temperature.