Russian Journal of Applied Chemistry, Vol. 75, No. 3, 2002, pp. 436 440. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 3,
2002, pp. 447 451.
Original Russian Text Copyright
2002 by Bazanova, Kholodkova, Gostikin.
ORGANIC SYNTHESIS
AND INDUSTRIAL ORGANIC CHEMISTRY
Reduction of 4,4 -Dinitrostilbene-2,2 -disulfonic Acid
with Hydrogen on Raney Nickel
I. N. Bazanova, N. V. Kholodkova, and V. P. Gostikin
Ivanovo State University of Chemical Engineering, Ivanovo, Russia
Received July 23, 2001
Abstract Reduction of 4,4 -dinitrostilbene-2,2 -disulfonic acid with hydrogen in aqueous solution on Raney
nickel yields a trisazo compound identical to Direct Yellow K dye.
In syntheses of some dyes and optical whitening
agents, 4,4 -diaminostilbene-2,2 -disulfonic acid (DAS)
is widely used as the diazo component. At present,
this acid is prepared from 4,4 -dinitrostilbene-2,2 -di-
sulfonic acid (DNS) by Bechaump reduction [1]. The
drawbacks of this process are large amounts of waste-
water, the necessity of utilizing the iron slime, and
labor-consuming isolation of the target product; they
make the process environmentally and economically
reflect all the transformations that DNS undergoes
under conditions of catalytic reduction. Bizhanov and
Zhubanov proved the possibility of hydrogenation of
the C=C double bond in the stilbene moiety with the
formation of 4,4 -diaminodibenzyl-2,2 -disulfonic acid
(DADB) and p-aminotoluenesulfonic acid; they also
noted formation in solution of diazo compounds and
unidentified unstable colored products. Formation of
an unidentified red product in reduction of DNS was
unacceptable. Heterogeneous-catalytic reduction of noted in [3, 4]. It was suggested that the compound
DNS with hydrogen in the liquid phase (see scheme)
is more efficient and economically feasible. However,
this process is accompanied by formation of by-prod-
ucts and intermediates decreasing the yield and quality
of DAS. The scheme of catalytic reduction of DNS
suggested by Bizhanov and Zhubanov [2] does not
imparting the red color to the reaction mixture in the
course of DNS reduction contains an azoxy group [4].
At the same time, DAS can be prepared by hydrogena-
tion of a mixture of azo dyes containing as major
component the trisazoxy dye Direct Yellow K (DYK)
of the following structure [7]:
SO3 H
CH
SO3 H
CH
SO3 H
SO3 H
O
N
O
1
1
1
1
N N
NO2
NO2
CH
CH
CH
CH
3
3
2
3
3
2
3
2
3
2
2
3
2
2
2
3
N N
O
N
CH
SO3 H
CH
SO3 H
1
1
1
1
SO3 H
SO3 H
According to the Haber Lukashevich Shmonina
scheme, nitro compounds are reduced in steps, with
Papers concerning the DAS production process
discuss the influence of various process conditions on
the product quality. This influence cannot be under-
stood without data on intermediates and by-products.
Therefore, the goal of this work was to prepare and
study intermediates and by-products arising in catalyt-
ic reduction of DNS. The results would allow us to
suggest a more detailed scheme of DNS reduction
with hydrogen on Raney nickel and to find conditions
for preparing the purest target product.
the products of incomplete hydrogenation of the NO
2
group being capable to react with each other to form
azoxy compounds [6, 7]. Therefore, presumably,
heterogeneous-catalytic reduction of DNS can yield
a product identical to DYK, imparting the red color
to the catalyzate and the cream color to the isolated
target product.
1070-4272/02/7503-0436$27.00 2002 MAIK Nauka/Interperiodica