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

Abstract

Densities, ρ, ultrasonic speeds, u, and viscosities, η 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, Vϕ, limiting apparent molar volume, Vϕ∘ and the slope, Sv, apparent molar compressibility, Ks,ϕ, limiting apparent molar compressibility, Ks,ϕ∘ and the slope, Sk, transfer limiting apparent molar volume, Vϕ,tr∘, transfer limiting apparent molar compressibility, Ks,ϕ,tr∘, hydration number, nH, 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, Δμ1∘# and per mole of solute, Δμ2∘# 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 Vϕ∘, Ks,ϕ∘, Vϕ,tr∘, Ks,ϕ,tr∘, B and Δμ2∘# 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.