Mb. Bogacki et al., HYDRATION AND INTERFACIAL ACTIVITY OF METHYL 8-PYRIDYLOCTANOATES AND EXTRACTION OF COPPER(II) FROM CHLORIDE SOLUTIONS, Colloids and surfaces. A, Physicochemical and engineering aspects, 110(3), 1996, pp. 263-272
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.