Solvation behavior of some vitamins in aqueous solutions of sodium chloride at different temperatures and at atmospheric pressure

Densities ρ, and viscosities η, of aqueous solutions of l-ascorbic acid, nicotinic acid, thiamine hydrochloride and pyridoxine hydrochloride have been determined in different concentrations of sodium chloride at temperatures 288.15–318.15 K. These data were used to calculate apparent molar volumes V2,ϕ, partial molar volumes at infinite dilution V2°, and viscosity B-coefficient (B). The corresponding transfer parameters at infinite dilution (ΔtrV2° and ΔtrB) have been calculated using the data in water reported earlier on these vitamins. The dB/dT values have also been calculated. Results have been discussed in terms of solute–solute and solute–solvent interactions, which are found to be very complex in these systems. Activation free energy of viscous flow has also been calculated for these vitamins + sodium chloride + water systems.