Application of silica-supported Fe–Cu nanoparticles in the selective hydrogenation of p-dinitrobenzene to p-phenylenediamine

Article abstract of DOI:10.1134/S0036024417020285

Supported bimetallic Fe–Cu/SiO₂ materials are synthesized, and their catalytic activity in hydrogenation of dinitrobenzene to phenylenediamine at 145–180°С and 1.3 MPa hydrogen pressure is studied for the first time. The best results (89% selectivity toward _p-phenylenediamine at complete conversion of _p-dinitrobenzene) are obtained for the sample synthesized via co-deposition with subsequent calcination at 300°С. The sample contains 7% iron and 3% copper. The formation of separate phases of metal oxides (for the catalysts prepared by impregnation) and mixed bimetallic oxide phases (in case of co-deposition procedure) in calcined samples is revealed via thermoprogrammed reduction with hydrogen.

Full text of DOI:10.1134/S0036024417020285

ISSN 0036-0244, Russian Journal of Physical Chemistry A, 2017, Vol. 91, No. 2, pp. 201–204. © Pleiades Publishing, Ltd., 2017.
Original Russian Text © A.A. Shesterkina, E.V. Shuvalova, O.A. Kirichenko, A.A. Strelkova, V.D. Nissenbaum, G.I. Kapustin, L.M. Kustov, 2017, published in Zhurnal Fizicheskoi
Khimii, 2017, Vol. 91, No. 2, pp. 201–204.
NANOMATERIALS
AND ENVIRONMENT
Application of Silica-supported Fe–Cu Nanoparticles in the Selective
Hydrogenation of p-Dinitrobenzene to p-Phenylenediamine
a
a
a
a
A. A. Shesterkina *, E. V. Shuvalova , O. A. Kirichenko , A. A. Strelkova ,
a
a
a,b
V. D. Nissenbaum , G. I. Kapustin , and L. M. Kustov
Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, 119991 Russia
a
b
Department of Chemistry, Moscow State University, Moscow, 119991 Russia
*
e-mail: anastasiia.strelkova@mail.ru
Received June 16, 2016
Abstract—Supported bimetallic Fe–Cu/SiO materials are synthesized, and their catalytic activity in
2
hydrogenation of dinitrobenzene to phenylenediamine at 145–180°С and 1.3 MPa hydrogen pressure
is studied for the first time. The best results (89% selectivity toward p-phenylenediamine at complete
conversion of p-dinitrobenzene) are obtained for the sample synthesized via co-deposition with subse-
quent calcination at 300°С. The sample contains 7% iron and 3% copper. The formation of separate
phases of metal oxides (for the catalysts prepared by impregnation) and mixed bimetallic oxide phases
(
in case of co-deposition procedure) in calcined samples is revealed via thermoprogrammed reduction
with hydrogen.
Keywords: Fe–Cu catalysts, dinitrobenzene hydration, phenylenediamine
DOI: 10.1134/S0036024417020285
INTRODUCTION
by solutions of metal salts (CIm) and by the co-depo-
sition of precursors of both metals onto the carrier
Aromatic amines obtained via the catalytic
reduction of corresponding nitrocompounds are
widely used in the synthesis of different compounds Vpor = 1.05 cm g ; D = 26 nm) was used as the
2
–1
using urea (CoD). KSKG silica gel (S = 108 m g ;
sp
3
–1
por
for fine organic synthesis and pharmaceutical
industry [1, 2]. Nickel-containing catalysts, as well
as catalysts based on platinum-group metals [3–8]
are the most commonly used for the selective
hydrogenation of dinitrobenzene (DNB) to phenyl-
enediamine (PhDA). The main drawback of these
catalysts is a high content of the active components
and their toxicity. The development and investiga-
tion of more effective and environmentally safe cat-
alytic systems remain important goals of modern
carrier. Copper nitrate, ammonium trioxalatoferrate
(
(
NH ) [Fe(C O ) ] · 3H O (98%, Acros Organics)
4 3 2 4 3 2
impregnation method) and iron (III) nitrate (co-
deposition method) were used as the initial com-
pounds. Once the metal precursors were supported,
the samples were dried at 60–110°С and then calcined
at 300°С. The calcined samples were reduced in a Н
2
flow at 300°С. We selected the temperatures on the
basis of thermal analysis and TPR-Н data for the
2
catalysis [9]. In particular, the catalysts containing samples. The synthesized materials were marked as
iron are of great interest, due to their relatively high xFeyCu–N–М, where х and у are the mass percent-
activity in hydrogenation reactions, abundance, low age of Fe and Cu, respectively; N is the method of syn-
cost, and low toxicity [10].
thesis; and M is the conditions of thermal treatment.
The goal of this work was to study the effects of The samples were characterized by TPR-Н
using the
2
the preparation procedure of the supported bimetal- technique described in [11].
lic Fe–Cu/SiO catalysts and the conditions of the
2
The catalytic hydrogenation was conducted in a
00 mL autoclave in the temperature range of 145–
thermal treatment on the catalytic activity and selec-
tivity of p-phenylenediamine formation from p-dini-
trobenzene.
1
1
80°C and initial hydrogen pressure of 1.3 MPa. The
autoclave was charged with 30 mL of 0.08 M DNB
solution in tetrahydrofuran and 0.2 g of catalyst.
Eicosan (0.100 g) was added as an internal standard.
EXPERIMENTAL
Supported bimetallic Fe–Cu catalysts were syn- The samples of the reaction mixture were analyzed by
thesized via the consecutive impregnation of a carrier gas-liquid chromatography.
201

2
02
SHESTERKINA et al.
Catalytic performance of Fe–Cu catalysts and the results from TPR
Catalyst
Тreact, °С
t, min
SPhDA, %
t1, min
S1 PhDA, %
ТTPR, °С
Н : M
2
7Fe2Cu-CIm-300С
166
105
53
130
55
150–270
0.66 (Cu)
0.55 (Fe)
270–500
7
Fe2Cu-CIm-300С-Н
Fe3Cu-CoD-300С
165
145
240
145
1.4
600
460
25.4
89
7
10.7
150–300
00–500
2.15 (Cu)
0.89 (Fe)
3
7
Fe3Cu-CoD-300С-Н
Fe3Cu-CoD-110В
175
166
400
65
5
–
–
7
8.8
175
68
200–320
20–500
2.49 (Cu)
0.86 (Fe)
3
3
.3Cu-CoD-110В
Fe-CoD-110В
169
166
240
330
0
–
–
–
–
220–400
230–500
1.51 (Cu)
0.66 (Fe)
7
63*
t, S
are the reaction time and p-PhDA selectivity corresponding to complete conversion of p-DNB; t , S1PhDA are the reaction time
1
PhDA
and p-PhDA selectivity at complete conversion of p-NA.
*
p-DNB conversion is 81%.
RESULTS AND DISCUSSION
300С sample obtained via co-deposition slowed down
the hydrogenation reaction (especially of the interme-
diate NA). A drop in both activity and selectivity
toward PhDA (2 times) is observed for the reduced
All synthesized bimetallic Fe–Cu catalysts are
active (see table) in the liquid-phase hydrogenation of
p-DNB to p-PhDA (as opposed to monometallic cat-
alysts). Hydrogenation proceeds via formation of
7
Fe2Cu-CIm-300С-Н sample. It should be noted
p-nitroaniline (p-NA) (Fig. 1). The catalysts obtained that 7Fe3Cu-CoD-110В sample only dried after co-
by co-deposition are more active and selective toward deposition displayed substantial catalytic activity
PhDA than catalysts obtained by impregnation. Anal- (table). This sample was much more active and selec-
ysis of the reaction mixtures obtained over the cata- tive than the monometallic samples obtained under
lysts prepared by impregnation reveals that DNB con- the same conditions and used as references.
version calculated on the basis of the internal stan-
The TPR studies of the samples of calcined cata-
lysts showed the presence of different supported
dard, generally exceeds the values calculated on basis
of catalyzate composition; this is the evidence of the
formation of products that are not detected by GLC, phases. The character, temperature, and degree of
explaining the low selectivity of these catalysts. The reduction of the metals in bimetallic samples depend
hydrogen reduction of the calcined 7Fe3Cu-CoD- largely on the preparation procedure used.
Content, %
100
p-DNB
p-NA
p-PhDA
80
60
40
20
0
30
60
90
120
t, min
Fig. 1. Dependences of catalyzate composition on the reaction time in the presence of the calcined catalyst 7Fe2Cu-CIm-300С,
obtained by sequential impregnation.
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 91
No. 2
2017

APPLICATION OF SILICA-SUPPORTED Fe–Cu NANOPARTICLES
203
I, arb. units
4
000
7
1
5
7
Fe2Cu-SIm-300C
1% FeO /SiO
% CuO/SiO
Fe3Cu-CoD-300C
x
2
3200
2400
1600
2
800
0
1
00
200
300
400
500
T, °C
Fig. 2. TPR-Н curves of bimetallic Fe–Cu samples calcined at 300°С and monometallic samples used as reference.
2
Analysis of the TPR curve shows that Cu and Fe undesirable. The most active centers of nitrogroup
were present mostly in the form of individual oxides hydrogenation are supposed to be the highly dispersed
in the bimetallic sample obtained via impregnation. CuO nanoparticles that possess the developed contact
Two intense signals are seen on the TPR curve of the
Fe2Cu-CIm-300C sample (Fig. 2). The initial pro-
area with the iron oxide nanoparticles.
7
file of the first signal within 150–250°С matches that
of the reduction of CuO nanoparticles in the refer-
ence monometallic sample. The shape and position
of the second peak within 350–420°С matches that
of the TPR curve of the reference sample containing
iron oxide nanoparticles. The calculated correspond-
ing hydrogen : metal molar ratios (table) is the evi-
dence of the total reduction of copper to metallic
state and the partial reduction of iron oxide.
CONCLUSIONS
It was shown for the first time that Fe–Cu oxide
nanoparticles supported on silica gel catalyze the
hydrogenation of dinitrobenzene to nitroaniline and
then to phenylenediamine under relatively mild condi-
tions: 145–170°С and an initial hyrdrogen pressure of
1.3 MPa. The catalytic properties of the supported
bimetallic Fe–Cu catalysts depend on the method of
synthesis and the conditions of thermal treatment.
The catalysts reduced in hydrogen are less active. The
best selectivity towards p-PhDA (89%) at complete
conversion of p-NA was obtained with the sample syn-
thesized by co-deposition of metal precursors with
urea, followed by calcination in air at 300°С; the sam-
ple contains 7 wt % of iron and 3 wt % of copper.
The TPR curve of the sample obtained via co-
deposition differs substantially from that of the
sample obtained by impregnation. A double signal
of high intensity is seen on the TPR curve of the
sample 7Fe3Cu-CoD-300C (Fig. 2); a decrease in
the intensity of the signal of hydrogen consumption
by the iron-containing phases, as well as the signal
shift toward lower temperatures, are observed. Such
behavior could be due to the formation of mixed
bimetallic phases with higher contents of iron ions.
ACKNOWLEDGMENTS
The Н : Cu ratio for the first peak, which is exag-
2
gerated by 300%, also confirms the formation of
mixed oxides (the table).
This work was supported by the Russian Science
Foundation, project no. 14-50-00126.
Our data shows that reduction in hydrogen at
3
00°С should lead to the complete reduction of parti-
REFERENCES
cles of copper-containing oxide phases in the samples
calcined at 300°C. A comparison with the results on
1
. A. I. Kozlov and V. L. Zbarskii, Ross. Khim. Zh.,
No. 3, 131 (2006).
0
catalytic performance shows that reduction to Cu is
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A Vol. 91 No. 2 2017

2
04
SHESTERKINA et al.
2
. S. Z. Levin, Processes of Catalytic Hydrogenation in Pro-
8. M. H. Brijaldo, F. B. Passos, H. A. Rojas, et al., Catal.
duction of Monomers and Intermediates (Khimiya, Mos-
Lett. 144, 860 (2014).
cow, 1966), p. 128 [in Russian].
9
. A. A. Shesterkina, L. M. Kozlova, O. A. Kirichenko,
3. L. Zhao, J. Chen, and J. Zhang, J. Mol. Catal. A:
et al., Russ. Chem. Bull. 65, 432 (2016).
Chem., 140 (2006).
4
. Y. Liu, J. Chen, J. Zhang, et al., Chem. Eng. Sci. 15, 63 10. A. A. Shesterkina, O. A. Kirichenko, L. M. Kozlova,
2007).
(
et al., Mendeleev Commun. 26, 228 (2016).
5
. N. M. Yoon, Bull. Korean Chem. Soc. 14, 281 (1993).
. M. M. Telkar, J. M. Nadgeri, C. V. Rode, et al., Appl.
1
1. L. M. Kustov, S. R. Al-Abed, O. A. Kirichenko, et al.,
6
Pure Appl. Chem. 86, 1141 (2014).
Catal. A: Gen. 295, 23 (2005).
7
. F. Cárdenas-Lizana, S. Gómez-Quero, C. J. Baddeley,
et al., Appl. Catal. A: Gen. 387, 155 (2010).
Translated by P. Vlasov
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 91
No. 2
2017