HYDRATION AND INTERFACIAL ACTIVITY OF METHYL 8-PYRIDYLOCTANOATES AND EXTRACTION OF COPPER(II) FROM CHLORIDE SOLUTIONS

The interfacial tension of individual methyl 8-pyridyloctanoates conta ining the hydrophobic group at different positions of the pyridine rin g was measured at the tolune/water interface. The extraction of copper (II) fom chloride solutions with these reagents was studied. Consideri ng solvent extraction, methyl 8-(2-pyridyl)octanoate had a worse orien tation at the interface than methyl 8-(3-pyridyl)octanoate and methyl 8-(4-pyridyl)octanoate. PM3 semiempirical quantum chemical computing i ndicates that the oxygen of the carbonyl group forms hydrogen bonds wi th water molecules more easily than the second oxygen atom and the nit rogen in the pyridine ring. However, at the adsorption layer, this hyd ration is possible only for methyl 8-(2-pyridyl)octanoate. Methyl 8-(3 -pyridyl)octanoate and methyl 8-(4-pyridyl)octanoate are strong copper extractants from chloride solutions, while extraction is not observed for methyl 8-(2-pyridyl)octanoate.