Abstract
In the present work, osmotic coefficients of aqueous mixtures of guanidinium chloride (GndmCl) and sodium l-aspartate (Na-l-Asp = (S)-aminobutanedioic acid sodium salt), previously determined at T = 298.15 K and 310.15 K, were described by ePC-SAFT (equation of state) and molecular interactions in ternary systems were deduced from activity coefficients. The electrolyte Perturbed-Chain Statistical ...
Abstract
In the present work, osmotic coefficients of aqueous mixtures of guanidinium chloride (GndmCl) and sodium l-aspartate (Na-l-Asp = (S)-aminobutanedioic acid sodium salt), previously determined at T = 298.15 K and 310.15 K, were described by ePC-SAFT (equation of state) and molecular interactions in ternary systems were deduced from activity coefficients. The electrolyte Perturbed-Chain Statistical Associating Fluid Theory ePC-SAFT, based on Wertheim's TPT1 perturbation theory is proved to be an excellent tool to model ternary amino acid salt + salt + water systems. ePC-SAFT modeling required the following steps. First, all the pure-component parameters were inherited from literature. Second, the binary interaction parameters to water were used as determined from the literature as well. Finally, a binary interaction parameter was required between the salt ion and the amino acid salt. We found that a satisfying modeling was obtained by setting the binary parameters between anion and cation to zero and using a binary interaction parameter k(ij) = -0.1 for Gndm(+) and the amino acid salt. Without fitting any additional parameters, osmotic coefficients, activity coefficients of water and of the solutes have been calculated, in good agreement with the experimental data.
Altmetric