THERMODYNAMIC CHARACTERIZATION OF THE LIQUID-LIQUID-EXTRACTION OF SILVER BY ACYCLIC DITHIA BENZENE-DERIVATIVES

A study of the liquid-liquid extraction equilibria between aqueous Ag( I) and 1,3-bis[(ethylthio)methyl]benzene, 1,3-bis[(pentylthio)methyl]b enzene and 1,3-bis[(octylthio)methyl]benzene in chloroform solution, i s reported. The results have been expressed in terms of solvent extrac tion reactions between Ag(I) in aqueous solution and the ligands in th e organic phase. A numerical analysis of the metal distribution data h as determined the following reactions to be responsible for the extrac tion process in all cases: Ag+ + L(org) + NO3- --> [LAg(NO3)](org) Ag + 2L(org) + NO3- --> [L2Ag(NO3)](org) From this analysis polynuclear species have also been found to be formed in the aqueous phase. Thus, trinuclear species [L3Ag3(NO3)(3)] were found to give the best interpr etation of the experimental data. (C) 1998 Elsevier Science B.V. All r ights reserved.