Solubility and Solvation Thermodynamics of a Series of Homologous α‑Amino Acids in Nonaqueous Binary Mixtures of Ethylene Glycol and Dimethyl Sulfoxide

• Published in: Journal of chemical and engineering data 2015-05, Vol.60 (5), p.1242-1250
• Main Authors: Mahali, Kalachand, Roy, Sanjay, Dolui, Bijoy Krishna
• Format: Article
• Language: English
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/je5007899

In this article the standard free energies (ΔG t 0(i)) and entropies (ΔS t 0(i)) of transfer of four homologous α-amino acids including glycine (Gly), dl-alanine (dl-Ala), dl-α-amino butyric acid (dl-Aba.) and dl-nor-valine (dl-n-Val) from ethylene glycol (EG) to nonaqueous mixtures of ethylene glycol and dimethyl sulfoxide (DMSO) at 298.15 K are reported. The Gibbs energies of solutions have been determined from solubility measurements of each amino acid at different temperatures, that is, from 288.15 to 308.15 K by “formol titrimetry”. The chemical parts of free energies (ΔG t,ch 0(i)) and entropies (TΔS t,ch 0(i)) of transfer of the homologous α-amino acids have been computed by subtracting the cavity effects and dipole–dipole interaction effects from the total transfer energies. The characteristics of the solvation thermodynamics of α-amino acids in EG-DMF and EG-ACN mixed solvent systems studied earlier are also discussed here for comparison.