Elucidation of molecular interactions between amino acid and imidazolium based ionic liquid in an aqueous system: Volumetric and acoustic studies

Abstract Some of the most active academic and scientific research faces of the past decade are on ionic liquids and their behavior for industrial purposes. In the present work, the densities and sound velocities of an amino acid (glycine) in pharmaceutically active ionic liquid 1-Butyl-3-methylimidazolium hexafluorophosphate [BMIm][PF6] solutions were measured at different temperatures ranging from 293.15 K to 318.15 K under atmospheric pressure. The experimental data has been further used to calculate volumetric and acoustic parameters such as apparent molar volumes, V Φ and apparent molar isentropic compression, K Φ partial molar expansion, E Φ 0 partial molar volume, V Φ 0 and partial molar isentropic compression K Φ 0 and corresponding empirical constants, S v and S k . The negative values are obtained for partial molar volume of transfer, Δt V Φ o at all temperatures and become more negative by increasing the concentration of the ionic liquid. The positive values of partial molar expansibilities, E Φ o are decreasing with an increase in temperature predict increasing electrostriction. The obtained values of expansibilities show the structure-making/breaking ability of glycine in investigated solutions.