Study on the synergistic extraction of cobalt(II) with lower fatty acids in the presence of heterocyclic amines and some metal ion separations

The synergistic extraction of cobalt(II) with a chloroform solution of propionic, butyric or valeric acid in the presence of β-picoline, pyridine or quinoline has been investigated. The effect of different variables, such as pH of the aqueous phase, and concentration of metal ion, acid and amine, is reported. On the basis of slope analysis the species extracted were generally found to be CoA 2.2HA.2B where HA is the acid and B the base, but CoA 2.HA.2B.H 2O for the butyric acid—quinoline system. The extraction constants were used to assess the relative effectiveness of the amines as synergists. From the extraction data, methods for separation of Co(II) from Mn(II), Cr(III), Fe(III), Zn(II), Cd(II) and Hg(II), with fairly high separation factors, have been worked out.