Temperature-Dependent Thermodynamic Properties of Amino Acids in Aqueous Imidazolium-Based Ionic Liquid

Abstract

Molecular interactions of amino acids with ionic liquids are significant to study the molecular stability and physicochemical properties of amino acids. Mixtures of amino acids l-leucine and N-acetyl-l-leucine + (0.005, 0.010, 0.030, and 0.050 mol·kg–1) aqueous solution of ionic liquid (1-butyl-3-methylimidazolium chloride) at temperature T = (288.15, 298.15, 308.15, and 318.15 K) have been studied by density and speeds of sound measurements. Volumetric properties have been obtained by utilizing data of density. Volumetric properties include apparent molar volumes, partial molar volumes at infinite dilution, limiting partial molar volumes of transfer at infinite dilution, apparent molar expansibility, etc. Similarly, speeds of sound measurements are utilized to calculate corresponding parameters like apparent molar isentropic compression, K ϕ,s, apparent molar isentropic compression at infinite dilution, K ϕ,s 0, and transfer compressibility at infinite dilution ΔK ϕ,s 0. Results confirmed the predominance of the hydrophilic–hydrophilic interaction over the hydrophobic–hydrophobic interaction in ternary solutions.

Solvation Properties of Branched-Chain Amino Acids in Aqueous Solutions of 1-Dodecyl-3-methylimidazolium Bromide at Different Temperatures: Volumetric and Acoustic Measurements

“…Figure 7 illustrates that experimental values are consistent with those found in the literature. The speed of sound values for (water + N-acetyl L-leucine) solutions also compete with those from the literature 54,55 data and are graphically represented in Figure 8. It has been found that some literature values show deviations from experimental data at higher concentrations.…”

“…Figure shows a graphical representation of the experimental density data for N -acetyl l -glycine compared to the literature data. − Figure demonstrates that recorded densities for the ( N -acetyl l -glycine + water) binary mixture follow a similar trend as the literature densities, that is, there is a decrease in density value as temperature increases. Experimental density data for N -acetyl l -leucine were compared with literature data, , and graphically presented in Figure . From Figure it is observed that there is some deviation from the literature data at higher concentrations.…”

“…Comparison of experimental and literature (■, experimental; ●, ref ; ▲, ref ) values of speed of sound for aqueous solution of N -acetyl l -leucine at different temperatures: (a) 288.15 K, (b) 298.15 K, (c) 308.15 K, (d) 318.15 K.…”

Exploring Various Molecular Interactions of Two Essential Amino Acids Prevalent in Aqueous Solutions of an Ionic Liquid by Density, Viscosity, Refractive Index, Conductance, Surface Tension, Nuclear Magnetic Resonance, Ultraviolet, and Computational Studies

“…The empirically measured values of densities of both AAs ( l -valine and l -leucine) in the aqueous solution of IL are listed in Tables S2–S4. Furthermore, the density values acquired for AAs in aqueous solutions were compared with those found in the literature − and are depicted in Figure S5. The analysis indicates that the experimentally measured density values align well with the literature values for the AA solution in water, as reported in refs and .…”