Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 7, pp. 1205−1210.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
L.G. Chekanova, M.G. Shcherban’, A.V. Radushev, T.D. Batueva, E.V. Baigachev, 2009, published in Zhurnal Prikladnoi Khimii,
2009, Vol. 82, No. 7, pp. 1109−1114.
OF SYSTEMS AND PROCESSES
Oxyethyl Hydrazides as Potential Flotation Agents
L. G. Chekanova
, M. G. Shcherban’
, A. V. Radushev
, T. D. Batueva
, and E. V. Baigacheva
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences, Perm, Russia
Perm State University, Perm, Russia
Received December 6, 2008
Abstract—Physicochemical (acid-base, solubility, stability against oxidation and hydrolysis) and surface-active
(wetting angles, surface tension, foaming) properties of N'-oxyethyl hydrazides of aliphatic carboxylic acids were
studied. The data obtained are analyzed in terms of the main requirements imposed on ﬂ otation agents.
Voltammograms in alkaline solutions were measured with
a PU-01 polarograph on a dropping mercury electrode at
potentials in the range from –2.41 to –0.11 V at a potential
sweep rate of 3 mV s
. A silver chloride electrode served
as reference, and platinum as auxiliary electrode. In other
cases, polarization curves were measured on a rotating
disc electrode at potentials of 0–1.07 V and a potential
sweep rate of 5 mV s
. The solubility was determined
gravimetrically . pK
were calculated by
the formulas :
= pH + log ,
= pH + log ,
are negative logarithms of the acid
dissociation constants of H
and HL, respectively;
+, and A
, optical densities of solutions
containing neutral, protonated, and deprotonated forms
of the reagents, respectively; and A, optical density of the
solution at a certain pH value.
The stability against hydrolysis was determined by the
extraction method . The surface tension at the water–air
interface was studied by stalagmometry; the foaming
kinetics and the wetting angles were analyzed using
standard techniques . To examine the ionic ﬂ otation,
ethanol solutions of collecting agents were introduced
Flotation processes are widely used in hydrometallurgy
and mining industry . This necessitates development
of new ﬂ oating agents with improved technological
properties, which should satisfy a number of requirements
. Aliphatic acid hydrazides are bidentate ligands and
form ﬂ otoactive precipitates of complexes with nonferrous
metal ions . Introduction of oxyethyl substituents at the
β-atom of nitrogen in hydrazides can impart additional
ing and surface-active, to the compounds obtained.
The aim of this study was to examine properties of
N'-(2-oxyethyl)hydrazides of aliphatic acids, necessary
for assessing the possibility of using these reagents in
ﬂ otation processes, and to analyze their ﬂ otation activity
with model Cu(II) solutions.
N',N'-Di-(2-oxyethyl)hydrazides of hexanoic, octanoic,
and undecanoic acids and N'-2-oxyethyl)hydrazide of
octanoic acid were synthesized at the laboratory of
organic complexing reagents, Institute of Technical
Chemistry, Ural Branch, Russian Academy of Sciences.
The individual nature and purity of the reagents was
confirmed by IR and
H NMR spectroscopies and
The optical density of solutions was measured with an
SF-2000 spectrophotometer, and the pH values, with an I-
160M pH-meter with glass and silver chloride electrodes.