The extraction of Co2+ by mixtures of acetylacetone (acac) and either pyridine (Py), benzylamine (ba), triethylamine (tea) or tripyridylamine (tpa)
bases in xylene solvent was investigated from an aqueous phase containing salts of LiCl, NaCl, KCl, RbCl and CsCl in concentrations
varying up to 3M. The different hydration properties of the alkali metal cations is show to affect very slightly the synergistic
solvent extraction of Co2+. This result, together with previously obtained thermodynamic data indicating the nonexistence of water molecules in the
extracted synergistic species, may explain the fact that these salts have no effect on the extraction of Co(acac)2 (N-base)2.