Molecular Interactions Of Two Biologically Active Molecules (L-Serine And L-Valine) In Aqueous [Hmim]Cl Solutions: Volumetric And Viscometric Approach

Mixtures of amino acids L-serine and L-valine + (0.05, 0.1, 0.2 and 0.3 mol.kg(-1)) aqueous solutions of ionic liquid 1-n-hexyl-3-methylimidazolium chloride, [Hmim]Cl, at temperatures T = (293.15, 298.15, 303.15, 308.15 and 313.15 and 318.15 K) have been studied using density and viscosity measurements. From density, the volumetric properties: the apparent molar volume, V-phi, limiting partial molar volume, V-phi(0), and expansibility, E-phi(0), standard molar volume of transfer, Delta V-phi(0), and hydration number, nH, were calculated. Similarly, from viscosity measurements and using the Jones-Dole equation and transition state treatment, the viscosity B coefficient and some activation parameters of viscous flow were calculated. These parameters, their variation with temperature and concentration, were discussed in terms of transition state theory. Based on the co-sphere overlap model, the solute-solute and solute-solvent interactions were discussed, including amino acids hydration, and structural effects. The structure making/breaking ability of the amino acids in solutions was also discussed using Hepler's constant and (dB/dT) variation. (C) 2021 Elsevier B.V. All rights reserved.