PHYSICAL PROPERTIES AND ACTIVITY COEFFICIENTS IN AQUEOUS MIXED ELECTROLYTE SOLUTIONS OF NaCl IN NaCl- MgCl2 – GLUTAMIC ACID - H2O AT 250C.

Abstract

The perturbed-chain statistical association theory (PC-SAFT) is applied to simultaneously describe
various thermodynamic properties (density, vapor-pressure depression, activity coefficient,
solubility) of aqueous solutions containing an amino acid or an oligopeptide. The 28 organic
compounds considered within this work are glycine, alanine, serine, proline, hydroxyproline,
valine, leucine, arginine, lysine, threonine, asparagine, tyrosine, histidine, cysteine, methionine,
aspartic acid, glutamic acid, R-ABA, R-isoABA, _-ABA, γ-ABA, R-AVA, γ-AVA, diglycine,
triglycine, dialanine, Gly-Ala, and Ala-Gly. If not yet available in literature, amino-acid solubility
data and activity coefficients were determined experimentally. To prove the predictivity of PC-
SAFT, osmotic coefficients in aqueous solutions containing two amino acids (glycine/valine and
alanine/ valine) were measured and predicted without applying any additional model parameters.