ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 6, pp. 987!990. + Pleiades Publishing, Inc., 2006.
Original Russian Text + E.A. Vlasova, I.Yu. Vashurina, Yu.A. Kalinnikov, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 6,
pp. 998 !1001.
AND INDUSTRIAL ORGANIC CHEMISTRY
Effect of Peat Humic Acids on the Kinetics
of Reduction of Anthraquinone Dye
with Sulfur-containing Reducing Agents
E. A. Vlasova, I. Yu. Vashurina, and Yu. A. Kalinnikov
Institute of Chemistry of Solutions, Russian Academy of Sciences, Ivanovo, Russia
Received January 11, 2006
Abstract-The influence of peat humic acids on the aerobic reduction of Chrome Green Anthraquinone
dye with sodium hydroxymethanesulfinate and thiourea dioxide in alkaline solutions was studied.
Textile dyeing with water-insoluble vat dyes neces-
sarily involves the stage of temporary reductive trans-
fer of the dye into solution, followed by its back oxi-
dation on a fiber. The reduction of vat dyes is based
on reversible quinone/hydroquinone reaction , which
requires that not only strong reductants such as hy-
droxymethanesulfinate (HMS) or thiourea dioxide
(TUDO), but also a catalyst should be used. The most
widely employed catalysts for this purpose are syn-
thetic anthraquinones , which are generally com-
ponents of commercial vat dyes. In some cases,
the catalysts are directly introduced into the printing
dye. In these cases, the most commonly used catalysts
are cobalt dioximates . Naturally, some part of
the indicated compounds, along with the unfixed dye,
is rejected to wastewater of textile mills.
It has been demonstrated that absolutely nontoxic
and environmentally friendly humic acid (HAs) can
be used as a full-value alternative to the synthetic re-
duction catalysts. These acids can be readily extracted
from peat .
Since the reduction of vat dyes is caused by only
the presence of the quinoid groups in them, it be-
comes possible to study this process with model com-
pounds readily soluble in water. Such model com-
pounds can be anthraquinone dyes.
In this study, we examined the influence of peat
humic acids on the kinetics of reduction of Chrome
Green Anthraquinone (CGA) (CI Acid Green 27)
with two sulfur-containing reducing agents, HMS
In the experiments, we used an aqueous solution
of HA salt obtained by alkaline extraction from peat,
using the standard procedure . HMS was purified
by recrystallization of the commercial product. TUDO
was synthesized as in . CGA dye was purified to
constant extinction coefficient .
The rate of CGA reduction by an excess amount of
the reductant was determined by measuring the optical
density at the absorption peak of the oxidized dye
= 612 nm, e = 10870 l mol
). It was de-
monstrated in the preliminary experiments that this
peak is well resolved from the absorption peak of
the reduced dye.
The rate of dithionite formation by decomposi-
tion of TUDO under aerobic conditions was also
determined spectrophotometrically at 315 nm (e =
8043 l mol
) on a Specord M-40 instrument.
The kinetic curves of reduction of CGA with HMS
and TUDO are shown in Fig. 1.
The CGA reduction is described by a first-order ki-
netic equation , which suggests that the initial CGA
molecule is involved in the reaction, i.e., that the re-
action is kinetically controlled by the dye concentra-
The reaction of the dye with sulfoxylate ions
(active reducing species formed in decomposition