Synergistic Effects of Mixed Solvents on the Solvent Extraction of Copper(II) Benzoates

By using 1-octanol-benzene and 2-octanone-benzene mixed solvents with a wide variety of mixing ratios, the extraction of copper(II) with benzoic acid was carried out at 25°C and an aqueous ionic strength of 0.1mol dm-3 (NaClO4). Each extraction equilibrium for these mixed-solvent systems was determined by a slope analysis and curve-fitting method. The monomeric and dimeric copper(II) benzoates were found to be responsible for all extraction systems. The present results have revealed the relationship between the partition constants of the monomeric extracted species, CuA2, and monomeric benzoic acid, HA. It has been proven that the present mixed solvents with a certain composition are superior to chloroform in the extraction of copper(II) by benzoic acid.