Osmotic and activity coefficients of glycine, dl-α-alanine and dl-α-aminobutyric acid in aqueous solutions at temperatures between 288.15 and 303.15K

Evaluation of the Capability of Ionic Liquid–Amino Acid Aqueous Systems for the Formation of Aqueous Biphasic Systems and Their Applications in Extraction

“…Nevertheless, for the aqueous solutions with concentrations higher than 0.8 mol kg –1 amino acid, the water activities of the amino acid solutions follow the order: l -Ser ≥ Gly > Ala > l -Pro. This unexpected trend can be related to the tendency of Gly and Ser for self-association. , Similar behavior has also been observed for the water activity of binary amino acid + water systems. ,− As can be seen from Table , the octanol/water partition coefficient (the ratio of a chemical’s concentration in the octanol phase to its concentration in the aqueous phase of a two-phase octanol/water system) of the studied amino acids follows the order: Pro > Ala > Ser > Gly, which is not in agreement with the trend of water activity data obtained in this work. In the case of the absence of self-association, we may expect similar behavior for the obtained water activity data.…”

Thermodynamics of the ternary systems: (water + glycine, l-alanine and l-serine + di-ammonium hydrogen citrate) from volumetric, compressibility, and (vapour + liquid) equilibria measurements

“…The evaluated parameters and corresponding deviations are given in table 6. The parameters obtained have been used for the prediction of the experimental water activity data of some binary (amino acids + H 2 O) systems [50,51] and the absolute relative percentage deviations (Dev%) are also given in table 6. The experimental water activity, a w , and osmotic coefficient, U, for the binary solutions studied are plotted against the molality, respectively, in figures 7 and 8.…”

“…Plot of the activity of water, a w , against molality, m, for the binary solutions at T = 298.15 K: s, L-serine (This work); Â, L-serine (reference[50]); M, glycine (this work); N, glycine (reference[50]); j, glycine (reference[51]); }, alanine (this work); }, alanine (reference[50]); +, alanine (reference[51]); , (NH 4 ) 2 HCit; -, calculated by the Wilson model.…”

The vapour pressures over saturated aqueous solutions of dl-2-aminobutyric acid, 4-aminobutyric acid, sodium-d-gluconate, sodium hippurate, and potassium magnesium-l-aspartate

“…With an exception of 2-aminobutyric acid, which was considered mainly in moderately concentrated solutions at T = 298.15 K [8,9], but also by Romero and Gonzáles [10] at T = (288.15 and 303.15) K, the vapour pressures in investigated systems are unknown in the literature. In this work, they were determined at saturation points in the T = (278 to 322) K temperature range.…”