A comparative solvent extraction study of manganese(II) with 8-Mercaptoquinoline, 8-Quinolinol and its analogues

Equilibrium distribution coefficients were determined for the extraction of manganese(II) with 8-mercaptoquinoline, 8-quinolinol and its 2-methyl, 4-methyl, 5-chloro and 5-nitro analogues as a function of pH and reagent concentration at ambient temperature. 8-Mercaptoquinoline forms a mono self-adduct with Mn(II) whereas simple 12 chelate formation was observed in the case of 8-quinolines. The adduct formation constant and the overall formations constants in the aqueous phase have been determined. A linear relationship was observed between the equilibrium constants, formation constants and the pK values of the chelating agents.Synergic enhancement was observed in the extraction of Mn(II) with 8-mercaptoquinoline in presence of pyridine and its methyl derivatives and the adduct formation constants of the 12, chelate to nitrogen base, adducts were evaluated.