Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 11, pp. 1997−2001.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
T.D. Batueva, A.V. Radushev, V.Yu. Gusev, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 11, pp. 1850−1854.
AND INDUSTRIAL ORGANIC CHEMISTRY
Extraction of Copper(II) from Weakly Acid
and Ammonia Media with N',N'-Dialkylhydrazides
of Aliphatic Carboxylic Acids
T. D. Batueva, A. V. Radushev, and V. Yu. Gusev
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences, Perm, Russia
Received December 22, 2008
Abstract—Dependence of physicochemical properties of N',N'-dialkylhydrazides of aliphatic carboxylic acids
(solubility in kerosene, acid-base properties) on the length of hydrocarbon radicals in the functional group was
studied. The extraction capacity for copper(II) salts in weakly acid and ammonia media was examined in the
range from pH 5–11 to a NH
content of 2.7 M. The capacity of the organic phase for copper(II) and re-extraction
conditions were determined for the example of N',N'-dibutylhydrazide of octanoic acid.
It has been suggested to extract copper(II) from
various media with more than 100 organic reagents and
their mixtures . Only few of these are suitable for
ammonia media; oxyoximes and β-diketones are most
widely used for this purpose [2, 3]. However, β-diketones,
e.g., Lix-54 , are hardly applicable at high ammonia
concentrations [3, 4]. The capacity of oxyoximes for
copper(II) is 2–2.5 times lower than that of β-diketones
and they transfer ammonia in noticeable amounts .
Therefore, a search for new improved extractive agents for
copper(II), especially those for extraction from ammonia
media, is a topical task. It was suggested to use hydrazides
of organic acids to recover copper(II) from acid solutions
with pH 0.5–5 [6–8]. Later, it was shown for the example
of N',N'-diethylbenzhydrazide  and especially some
N',N'-dialkylhydrazides of 2-ethylhexanoic acid [10, 11]
that N',N'-alkylation improves the extraction properties of
the reagents obtained and provides recovery of copper(II)
from weakly acid and ammonia media.
The aim of our study was to examine homologous
series of N',N'-dialkylhydrazides of 2-ethylhexanoic
and n-aliphatic acids as extractive agents for recovery
of copper(II) from ammonia media and to ﬁ nd the most
promising among these compounds.
N',N'-Dialkylhydrazides of 2-ethylhexanoic acid
(HL) were produced using methods similar to those
described previously . The compounds were puriﬁ ed
by recrystallization from acetone : water or EtOH :
water mixtures. The individual state and purity of the
reagents were conﬁ rmed by TLC and IR and
spectroscopic data and by analysis for the content of the
main substance by heterophase titration with sodium
lauryl sulfate .
The IR spectra were measured on a Bruker IFS 66/S
Fourier spectrometer, and the
H NMR spectra, on
a MERCURY plus 300 spectrometer in CDCl
. The optical
density was determined with an SF-26 spectrophotometer
and KFK-3 photocolorimeter, pH values were measured
with EV-74 and I-160M ion meters with glass and silver
chloride electrodes. The melting points were determined
with an instrument of the PTP type.
Reagents of pure and analytically pure grades were
used. Aviation kerosene of RT brand was taken without
any additional puriﬁ cation. Titers of standard copper(II)
sulfate solutions were found using chelatometry .
The extraction equilibria were studied as follows. To
1 ml of a 0.1 M CuSO
solution placed in a separating
funnel were added various amounts of ammonia or H
to create as a certain solution pH and the volume was
brought to 10 ml with water. After 5 min of shaking with