Thermodynamic Study of L-alanine in Aqueous Solutions of 1-Hexyl-3-Methylimidazolium Ibuprofenate as an Active Pharmaceutical Ingredient Ionic Liquid (API-IL)

The present work reported density, viscosity, speed of sound, electrical conductivity and refractive index data of L-alanine in the aqueous solutions of 1-hexyl-3-methylimidazolium ibuprofenate at T= 298.15 K. Using the measured data, partial molar volume of transfer ( ), partial molar isentropic compressibility of transfer ( ), viscosity B-coefficient of transfer (∆traB), ion association constant (KA) and molar refraction (RD) quantities were calculated. The obtained parameters provide the information about the solvation properties of aqueous solutions of L-alanine in the presence of [HMIm][Ibu]. The positive values of , and ∆traB are indicative of the ion-polar and polar-polar interactions between [HMIm][Ibu] and L-alanine. In addition, decreeing the KA values with addition of L-alanine to the [HMIm][Ibu] solutions suggests that the ion pair formation don’t proceed spontaneously at higher concentration of amino acid.