1979 Volume 20 Issue 3 Pages 111-118
The distribution of Cu, Ni, Co and Mn between an aqueous solution of constant ionic strength and Versatic Acid 911 diluted with benzene was investigated. Only one extracted species of Cu was revealed to have a dimeric structure of the composition (CuR2·RH)2, while both monomer and dimer were found in the extraction of Ni, Co and Mn. The curve-fitting method was employed to determine these species, from which the composition of the extracted species was found to be NiR2·4RH and (NiR2·2RH)2, CoR2·4RH and (CoR2·2RH)2, and MnR2·4RH and (MnR2·2RH)2, respectively. The apparent equilibrium constants of the above species and those between monomer and dimer were also determined. The curve-fitting method was proved to be a precise method for determining the equilibrium constants and extracted species.