Abstract
In this work thermodn. properties of electrolyte/amino acid/water solns. were measured and modeled. Osmotic coeffs. at 298.15 K were measured by means of vapor-pressure osmometry. Amino-acid soly. at 298.15 K was detd. gravimetrically. Considered aq. systems contained one of the four amino acids: glycine, L-/DL-alanine, L-/DL-valine, and L-proline up to the resp. amino-acid soly. limit and one ...
Abstract
In this work thermodn. properties of electrolyte/amino acid/water solns. were measured and modeled. Osmotic coeffs. at 298.15 K were measured by means of vapor-pressure osmometry. Amino-acid soly. at 298.15 K was detd. gravimetrically. Considered aq. systems contained one of the four amino acids: glycine, L-/DL-alanine, L-/DL-valine, and L-proline up to the resp. amino-acid soly. limit and one of 13 salts composed of the ions Li+, Na+, K+, NH4+, Cl-, Br-, I-, NO3-, and SO42- at salt molalities of 0.5, 1.0, and 3.0 mol · kg-1, resp. The data show that the salt influence is more pronounced on osmotic coeffs. than on amino-acid soly. The electrolyte Perturbed-Chain Statistical Assocn. Theory (ePC-SAFT) was applied to model thermodn. properties in aq. electrolyte/amino-acid solns. In previous works, this model had been applied to binary salt/water and binary amino acid/water systems. Without fitting any addnl. parameters, osmotic coeffs. and amino-acid soly. in the ternary electrolyte/amino acid/water systems could be predicted with overall deviations of 3.7̂ and 9.3̂, resp., compared to the exptl. data. [on SciFinder(R)]
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