Guanidinium Cation Effect on the Water Activity of Ternary (S)Aminopentanedioic Acid Sodium Salt Solutions at 298.15 and 310.15 K

Vapor pressure measurements were applied to the systems guanidinium hydrochloride (methanamidine hydrochloride) + sodium l-glutamate (S-aminopenthanedioic acid sodium salt) + water at varying concentrations of GndmCl and Na-l-Glu (m(NaGlu) = 0.1–1.6 mol/kg; m (GndmCl) = 0.104 mol/kg, 0.301 mol/kg, 0.684 mol/kg) for two temperatures, T = 298.15 and 310.15 K. From the experimental results, activities of water, activity coefficients of water, and the corresponding osmotic coefficients of the mixtures Na-l-Glu + GndmCl + water have been calculated, both being directly related to the chemical potentials of the different components and therefore to their Gibbs energy. The modeling of the components’ chemical potentials in ternary GndmCl + Na-l-Glu + water solutions was done with the equation of state ePC-SAFT. Osmotic coefficients, fugacity coefficients, and activity coefficients of the mixture components were modeled. Experimental osmotic coefficient values demonstrate nonlinear concentration dependences with ...