Mb. Bogacki et al., DIALKYL PYRIDINEDICARBOXYLATES EXTRACTION ABILITY TOWARD COPPER(II) FROM CHLORIDE SOLUTIONS AND ITS MODIFICATION WITH ALCOHOLS, Industrial & engineering chemistry research, 36(3), 1997, pp. 838-845
Dipentyl pyridinedicarboxylates (denoted hereafter as L) with differen
t positions of the ester groups were synthesized and used for copper(I
I) extraction from chloride solutions containing up to 10 mol . L(-1)
Cl-. The effect of decanol addition on copper extraction was studied.
A molecular modeling technique was used to estimate the structures of
extractants, copper complexes, and associates with alcohol. It was fou
nd that the ability of pyridinecarboxylates to extract copper depends
on the aqueous phase composition and the position of the ester groups
in the pyridine ring. All the investigated compounds except dipentyl p
yridine-2,6-dicarboxylate extract copper(II) by formation of CuCl(2)L(
2) complexes. Dipentyl pyridine-2,6-dicarboxylate forms another type o
f complex, probably CuCl(2)L. However, this compound is not suitable f
or copper extraction as its copper complex precipitates. Dipentyl pyri
dine-3,5-dicarboxylate was found to be the most suitable extractant am
ong the various compounds listed. Finally it is shown that the possibi
lities to modify the extraction ability of pyridinecarboxylates with a
hydrophobic alcohol such as decanol are relatively weak. Some enhance
ment was, however, observed when 20% of decanol was added to the organ
ic phase containing dipentyl pyridine-3,5-dicarboxylate.