Study of solute-solute and solute-solvent interactions of streptomycin sulphate in aqueous-l-asparagine/l-glutamine solutions at different temperatures by using physicochemical methods

Abstract

The densities, ρ of streptomycin sulphate in water and in aqueous l-asparagine/l-glutamine (1% and 2% l-asparagine/l-glutamine in water, w/w) solvents were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K; and ultrasonic speeds, u and viscosities, η of these solutions were measured at temperatures (298.15, 303.15, 308.15, 313.15 and 318.15) K and at atmospheric pressure. The ρ, u and η data have been used to calculate apparent molar volumes, Vϕ, limiting apparent molar volumes, Vϕ°, apparent molar compressibilities, Ks,ϕ, limiting apparent molar compressibilities, Ks,ϕ°, transfer volumes, Vϕ,tr°, transfer compressibilities, Ks,ϕ,tr° and limiting partial molar expansibilities, Eϕ°. The viscosity data have been used to determine Falkenhagen Coefficients, A and Jones-Dole coefficients, B. These parameters have been discussed in terms of solute-solute and solute-solvent interactions prevailing in these solutions. The structure making/breaking ability of streptomycin sulphate in these solutions is also discussed. Furthermore, the Gibbs free energies of activation of viscous flow per mole of solvent, Δμ1°# and per mole of solute, Δμ2°#, entropies, ΔSο and enthalpies, ΔHο of activation of viscous flow were also calculated and discussed in terms of transition state theory.