Evaluation of distribution ratio in ion pair extraction using fundamental thermodynamic quantities

• Published in: Analytica chimica acta Vol. 373; no. 2; pp. 213 - 225
• Main Authors: Yoshida, Yumi, Matsui, Masakazu, Shirai, Osamu, Maeda, Kohji, Kihara, Sorin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 11.11.1998; Elsevier
• Subjects: Analytical chemistry; Chemical and thermal methods; Chemistry; Exact sciences and technology; Electrochemical potential; Separation method; Equilibrium constant; Gibbs free energy; Liquid liquid extraction; Chemical method; Ion pair; Activity coefficient; Solvent extraction; Physicochemical properties
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/S0003-2670(98)00367-5

Equations were derived for the quantitative expressions of distribution ratios, D M, in ion pair extractions of a cation, M +, with a counter ion, X −, from water, W, to an organic solvent, O, in the absence and presence of a special complexing neutral ligand, L, in O by using standard transfer free energies of M + and X − from W to O, ion pair formation constants of M + with X − in W and O, the stability constant of the complex, (ML) +, in O and the ion pair formation constant of (ML) + with X − in O. The D M values calculated by substituting the constants determined by electrochemical methods into the derived equations agreed very well with those obtained experimentally by ion pair extraction, which means that the extraction processes assumed in the derivation of the equations was reasonable.