Physicochemical study of solute-solute and solute-solvent interactions of glycine, L-alanine, L-valine and L-isoleucine in aqueous-D-mannose solutions at temperatures from 293.15 K to 318.15 K

摘要

Densities, rho, ultrasonic speeds, u, and viscosities, eta of aqueous-D-mannose (2.5% and 5% of D-mannose, w/w in water) and of solutions of glycine, L-alanine, L-valine and L-isoleucine in aqueous-D-mannose solvents were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and at atmospheric pressure. These experimental values have been used to calculate the apparent molar volume, V-phi, limiting apparent molar volume, V-phi degrees and the slope, S-v, apparent molar compressibility, K-s,K-phi, limiting apparent molar compressibility, K-s,K-phi degrees and the slope, S-k, transfer limiting apparent molar volume, V-phi,V-tr degrees, transfer limiting apparent molar compressibility, K-s,K-phi,K-tr degrees, hydration number, n(H), Falkenhagen coefficient, A, Jones-Dole coefficient, B, and temperature derivative of B-coefficient, dB/dT. The Gibbs free energies of activation of viscous flow per mole of solvent, Delta mu(1)degrees(#) and per mole of solute, Delta mu(2)degrees(#) were also calculated. The results are interpreted in terms of solute-solvent and solute-solute interactions in these systems. The structure-making/breaking ability of the amino acids has also been discussed in terms of the sign of dB/dT. Furthermore, the values of V-phi degrees, K-s,K-phi degrees, V-phi,V-tr degrees, K-s,K-phi,K-tr degrees, B and Delta mu(2)degrees(#) have been split into groups' contributions of the amino acids using linear correlation with number of carbon atoms in the alkyl chain of the amino acids. (C) 2016 Elsevier Ltd. All rights reserved.