Page 1
Kinetics and mechanism of the hydrogenationof m-dinitrobenzene to m-phenylenediamine
Hugo Rojas • Gloria Borda • Marıa Brijaldo •
Patricio Reyes • Jesus Valencia
Received: 4 July 2011 / Accepted: 25 September 2011 / Published online: 7 October 2011
� Akademiai Kiado, Budapest, Hungary 2011
Abstract The hydrogenation of m-dinitrobenzene to m-phenylenediamine was
carried out as a model hydrogenation reaction of importance to the pharmaceutical and
fine chemicals industries with the aim of investigating the kinetics of the reaction. The
effect of different conditions: hydrogen pressure, m-dinitrobenzene concentration,
reaction temperature, and weight of catalyst on the conversion of m-dinitrobenzene
and the yield of m-phenylenediamine were studied using Pt/TiO2 catalyst. During the
kinetic study, the intermediate m-nitroaniline was detected. Therefore, the overall
reaction was treated as consecutive reactions: first the reduction of m-dinitrobenzene
to m-nitroaniline and then, the reduction of m-nitroaniline to m-phenylenediamine.
The apparent activation energies of the reaction were determined in each step, to be
33.4 ± 0.4 and 39.8 ± 0.6 kJ/mol. Those results indicated that the hydrogenation of
m-nitroaniline toward m-phenylenediamine is the rate determining step in the
hydrogenation of m-dinitrobenzene. Two rate equations assuming Langmuir–
Hinshelwood mechanism provided the best fit to the experimental data.
Keywords m-Dinitrobenzene � Hydrogenation � Catalyst � Initial rate �Kinetic study
H. Rojas (&) � G. Borda � M. Brijaldo
Grupo de Catalisis (GC-UPTC) Universidad Pedagogica y Tecnologica de Colombia,
Escuela de Quımica, Facultad de Ciencias, Av. Norte, Tunja, Colombia
e-mail: [email protected]
P. Reyes
Facultad de Ciencias Quımicas, Universidad de Concepcion, Casilla 160-C, Concepcion,
Chile
e-mail: [email protected]
J. Valencia
Centro de Catalisis Heterogenea, Departamento de Quımica, Facultad de Ciencias,
Universidad Nacional de Colombia, Bogota, Colombia
e-mail: [email protected]
123
Reac Kinet Mech Cat (2012) 105:271–284
DOI 10.1007/s11144-011-0380-6
Page 2
Introduction
The hydrogenation of mononitroaromatic compounds to aromatic amines is
ordinarily carried out in vapor-phase reactions using either a fixed bed or fluidized
catalyst. However, the low vapor pressures and thermal instability of dinitro and
higher polynitroaromatic compounds advise the use of a liquid-phase reaction [1].
The selective hydrogenation of nitro-compounds is commonly used to manufacture
amines, which are important intermediates for dyes, urethanes, agrochemicals and
pharmaceuticals, often produced on a large industrial scale [2].
The hydrogenation of m-dinitrobenzene (m-DNB) to m-phenylenediamine
(m-PDA) is one of the most common reactions in the fine chemicals and
pharmaceutical industries. The commercial importance of m-phenylenediamine has
long been recognized [3]. It is an intermediate in the manufacture of some polymers,
dyestuff and other materials. With the increasing application of engineering
materials, especially aromatic polyamide fibers and polyurethane, the demand for
m-phenylenediamine is growing [4]. Because of its wide applications, the
production of m-phenylenediamine is gaining importance; and hence has increased
the need for the reduction of m-dinitrobenzene to m-phenylenediamine.
The selective hydrogenation of the nitro group in the presence of other reducible
functional groups is an important reaction to produce functionalized anilines as
industrial intermediates for a variety of specific and fine chemicals [5]. For such
polynitroaromatics, the rate of reduction for the first nitro group is generally much
more rapid than the rate of reduction of the remaining nitro groups. In most cases,
the rate of subsequent reduction is so slow that the process is effectively stopped
after the first nitro group is reduced [6]. The search effectiveness of systems is
particularly marked in the synthesis of m-phenylenediamine (i.e., reduction of both
–NO2 groups) from m-dinitrobenzene where the formation of m-nitroaniline (m-NA)
is also promoted.
Conventional synthesis via Fe promoted reduction in HCl (the Bechamp process)
produces a sludge containing the target product and toxic by-products, which
require costly and difficult downstream separation/waste treatment steps where low
overall product yields have limited the viability of this production route [7]. In an
attempt to overcome these limitations, ‘‘green’’ syntheses based on noble metal
catalysts are currently under investigation. Supported noble metals are the best
catalysts for the catalytic hydrogenation of nitroarenes, which has replaced the old
Bechamp process [2]. Catalytic hydrogenation leads to products with higher purity
and at lower cost, been investigated in detail [8, 9].
The catalytic hydrogenation of m-DNB has been reported using catalysts based
on both base transition metals such as nickel, copper [10–12] and noble metals such
as palladium and ruthenium [13, 14], but they generally lead to the formation of
m-nitroaniline (m-NA), hence the development of a catalytic system to achieve a
high selectivity to m-PDA is highly desirable. As an important member of the
platinum group metals, platinum is well known as a novel catalyst for selective
hydrogenation of aromatic ring to cycloalkenes, halonitroaromatics to aromatic
haloamines [15]. Catalytic hydrogenation of m-dinitrobenzene using platinum group
272 H. Rojas et al.
123
Page 3
catalysts is the actual method of producing m-phenylendiamine. This method
provides high selectivity and yields of m-PDA at low cost.
Although limited information is available in the literature on the kinetics of the
hydrogenation of m-dinitrobenzene, it is reasonable to assume that m-dinitrobenzene
behaves in a similar way to other aromatic nitro compounds [16]. Some researchers
used a Langmuir–Hinshelwood (L–H) type model to describe the kinetics of the
reaction [17]. A mechanism for the hydrogenation of nitro compound was suggested
by Cardenas et al. [18] who described the surface chemical kinetics of the reaction.
They have demonstrated that the nitro-group reduction m-DNB can proceed via a
consecutive and/or parallel mechanism. The two possible pathways are identified in
the reaction; the formation of m-PDA can take place via a consecutive (with m-NA
as reaction intermediate) and/or a parallel.
The effects of reaction temperature and hydrogen pressure were examined [15].
Both variables affect the reaction rate but not the selectivity. m-NA could be
obtained at a very high selectivity. Maximum yield of m-NA (97.9%) was obtained
in methanol and in the presence of a low concentration of the Sn4? modifier. Veena
[19] reported that the m-DNB gave 90% overall conversion at 95% selectivity with
respect to m-NA in 2.5 h. If catalyst loading increases, selectivity with respect to m-
NA decreases, and therefore lower catalyst loading (0.1% w/v) is used. Hydrogen
pressure did not show effect on the reaction rate in the range of 1.0–3.4 MPa.
In this work, titania supported platinum catalysts have been examined for the
liquid-phase hydrogenation of m-dinitrobenzene. The effects of hydrogen partial
pressure, initial concentration, catalyst loading and temperature on the catalytic
performance were intensively investigated. Kinetic data were interpreted using the
Langmuir–Hinshelwood model.
Experimental
Synthesis of Pt/TiO2 catalyst
Pt/TiO2 catalyst was prepared by impregnation of TiO2 (DEGUSA P-25) with an
aqueous solution of H2PtCl6 to give a Pt loading of 5 wt%. The obtained solid was
dried at 393 K for 6 h, calcined in air at 663 K for 4 h, and reduced in situ at 773 K
for 2 h prior to the characterization or catalyst testing. Additional information
dealing with preparation procedure and characterization has been previously
reported [20].
Characterization
The characterization of the catalyst by nitrogen adsorption at 77 K and hydrogen
chemisorption at 298 K was carried out in a Micromeritics ASAP 2010 apparatus.
Metal particle size was determined by TEM micrographs obtained in JEOL Model
JEM-1200 EXII. Reduction programmed temperature (H2-TPR) was carried out in a
Micromeritics TPD/TPR 2900 apparatus.
Hydrogenation of m-dinitrobenzene to m-phenylenediamine 273
123
Page 4
Kinetic measurements
The substrate, m-dinitrobenzene, used in the present study was provided by Merck
([99%). Reactions were conduced in a in a batch reactor at a constant stirring rate
(1,000 rpm). For all the reactions, 50 cm3 of ethanol solution was used. Prior the
experiment, all catalysts were reduced in situ under hydrogen flow of 20 cm3/min at
atmospheric pressure and temperature of 773 K. The absence of contact between air
and the catalyst before the reaction was assured through He purge. Additionally,
when the reactor was loaded with the catalyst and reactants, the absence of oxygen
was assured by flowing He through the solution during 30 min. In all reactions,
internal diffusion limitations were also shown to be absent by applying the Weisz–
Prater parameter [21, 22] which gave a value maximum of 0.19. Therefore, all these
result indicate the absence of any transport limitations from the kinetic data included
in this paper. To carry out the kinetic study over the catalyst only one variable
was modified in each experiment, keeping constant all the others. The effect of
m-dinitrobenzene concentration was studied in the concentration range from 0.025 to
0.2 M; hydrogen partial pressure in the range from 0.41 to 0.82 MPa; reaction
temperature between 333 and 363 K; and the catalyst weight, ranged from 0.05 to
0.2 g. Reaction products were analyzed on a gas chromatograph (GC) (Varian 3400)
furnished with an HP5 capillary column of (30 m 9 2.5 mm 9 0.25 lm). The GC
analyses were performed using a flame ionization detector using He as carrier. Under
these analytical conditions, the retention time of the reported reactants and products
were: m-DNB: 13 min; m-NA: 17 min and m-PDA: 8 min.
Results and discussion
Catalyst characterization
The BET surface area, H/Pt ratio and Pt average particle size of the used Pt/TiO2
catalyst were determined. The BET surface area of Pt/TiO2 catalyst (60.2 m2/g) is
slightly lower than the titania support (61.5 m2/g) which may be attributed to a
partial blockage of the pore structure of the support by metallic crystallites. This
behavior is in agreement with some earlier research [23, 24]. However, Shimizu
et al. [25] found that with metallic impregnation of supports, the surface area not
was affected. The H/Pt ratio (0.11) is low compared with others results obtained in
research using metallic catalysts supported on titania, reduced at low temperature
(473 K). This behavior is explained by the SMSI effect (strong metal-support
interaction) [26]. This occurs because titania is a partially reducible oxide and at
high temperature reduction, a slight reduction may take place leading to partially
reduced species (TiO2-x) which can easily migrate over small metal particles.
Similar results have been reported by Rojas et al. [27] and Reyes et al. [28] using
Ir/TiO2 and Ir/TiO2–SiO2 catalysts in hydrogenation reactions of a–b unsaturated
aldehydes. The average particle size (6.5 nm) was determined through transmission
electronic micrographs. The H2-TPR results exhibited signals ascribed to the
presence of surface oxychloroplatinum complex (PtClxOy) at 340 K [29]; signals
274 H. Rojas et al.
123
Page 5
related with the reduction of surface PtOx to metallic platinum at 440 K [30]; and
signals assigned at partially reduced titania lead to surface TiO2-x species after
hydrogen at high temperatures (above 673 K) [31].
Effect of hydrogen partial pressure
The effect of hydrogen partial pressure on the hydrogenation activity was studied by
varying the partial pressure (0.41, 0.54, 0.68, and 0.82 MPa), keeping constant the
m-dinitrobenzene concentration (0.1 M), the reaction temperature (343 K) and the
catalyst weight (0.1 g). Fig. 1 shows the evolution of the conversion level with time
at temperature of 343 K. It can be seen that the activity increases as hydrogen
pressure increases. In the same way, it can be seen that at low pressures (0.41 and
0.54 MPa), the formation to m-phenylenediamine does not occur. At a pressure of
0.63 MPa, the formation of aromatic amine begins, and when the hydrogen pressure
is much higher (0.82 MPa), the yield of m-phenylenediamine at 7 h of reaction
reaches 71.2% (Fig. 2). It has been reported that the hydrogen pressure affects the
reaction rate at pressures lower than 1 MPa but if the pressure increases to reach the
pressure range of one at 4 MPa [15], no further effect was detected. Similar trends
have been observed in the nitrobenzene hydrogenation on Ni catalysts [32].
Fig. 3 displays a typical concentration plot of m-dinitrobenzene hydrogenation
as a function of time over the studied catalyst at hydrogen pressure (0.82 MPa),
temperature (343 K) and weight of catalyst (0.1 g). It can be seen that the only
products in m-dinitrobenzene hydrogenation over Pt/TiO2 catalyst were m-nitroan-
iline (intermediate) and m-phenylenediamine (final product) which correspond to
the partial and total NO2 groups hydrogenation. The m-dinitrobenzene concentration
decreases with time, while the m-nitroaniline concentration increases, attains a
maximum value and then decreases. The m-phenylenediamine concentration
continuously increases whit time. In the m-dinitrobenzene hydrogenation, a linear
Fig. 1 Evolution of the conversion with time at different pressures
Hydrogenation of m-dinitrobenzene to m-phenylenediamine 275
123
Page 6
dependency in the initial reaction (r0) rate with hydrogen partial pressure was found
as can be seen in Table 1.
The initial reaction rate can be determined using the initial rate method [33], by
the following equation:
r0 ¼ � dcAð Þ= dtð Þt¼0 ð1ÞHere, r0 is the initial reaction, cA is the initial substrate concentration (m-DNB)
and t is reaction time. By a plot of concentration of m-DNB versus reaction time
(until 30 min), the initial rate was obtained from the slope a time near zero.
Effect of the m-dinitrobenzene concentration
The effect of m-dinitrobenzene concentration on the hydrogenation rate was
examined by using four different m-dinitrobenzene concentrations (0.025, 0.05, 0.1,
Fig. 2 Evolution of the yield of m-phenylenediamine with time at different pressures
Fig. 3 m-Dinitrobenzene concentration and hydrogenate products over Pt/TiO2 catalyst (0.82 MPa,334 K, 0.1 M and 0.1 g of catalyst)
276 H. Rojas et al.
123
Page 7
and 0.2 M). The catalyst was previously reduced at 773 K. Fig. 4 shows the
evolution of the conversion with time at constant hydrogen pressure (0.82 MPa),
temperature (343 K) and weight of catalyst (0.1 g). The detected products were m-
nitroaniline and m-phenylenediamine. An increase in the activity can be observed as
the m-dinitrobenzene concentration (0.025 M) decreases. This behavior is explained
considering those at lower reactant concentration, a higher fraction of active sites
are available to adsorb m-dinitrobenzene and hydrogen molecules and consequently
the conversion increases.
Table 1 shows the yield of m-phenylenediamine with the effect of m-dinitroben-
zene concentration; the yield of m-phenylenediamine increases with lower
m-dinitrobenzene concentrations. These results may be explained considering
that when an important fraction of the active sites are covered by the adsorbed
m-dinitrobenzene molecules, the sites containing adsorbed hydrogen decreases then
the hydrogenation ability is reduced leading mainly to m-nitroaniline.
Table 1 Initial rates (r0) and
yields for m-phenylenediamine
(%), at different hydrogen
pressures, m-dinitrobenzene
concentrations and weights of
catalyst
a Yield to m-phenylenediamine
at reaction time of 7 h
Parameter Initial rate/g
cat [r0 (mol/Lg s)]
Yielda (%)
H2 pressure (MPa) 0.41 6.0 9 10-5 –
0.54 7.0 9 10-5 –
0.68 1.0 9 10-4 9.5
0.82 1.4 9 10-4 71.2
Concentration (M) 0.025 6.1 9 10-4 87.3
0.05 1.1 9 10-4 81.4
0.1 1.4 9 10-4 71.2
0.2 1.5 9 10-5 3.5
Weight catalyst (g) 0.05 1.2 9 10-4 49.2
0.1 1.4 9 10-4 71.2
0.2 1.7 9 10-4 97.3
Fig. 4 Evolution of the conversion with time at different m-dinitrobenzene concentration
Hydrogenation of m-dinitrobenzene to m-phenylenediamine 277
123
Page 8
Effect of the weight of catalyst
The effect of the catalyst weight was studied using 0.05, 0.1 and 0.2 g of catalyst,
while keeping the other experimental conditions constant. Fig. 5 shows the
evolution of the conversion level with time at a constant temperature (343 K), for
the studied catalyst. An increase in the activity can be noted as the catalyst weight
increases. In the m-dinitrobenzene hydrogenation, the maximum yield of aromatic
amine reaches employing the higher weight of catalyst (0.2 g). This fact is in
agreement with the conversion results. A similar behavior in the research of Veena
[19] was reported. They observed that a reduction in the m-nitroaniline formation
occurred with an increases in the weight of catalyst; therefore, this generated an
increase in the m-phenylenediamine. As expected, a linear dependency is seen in the
initial reaction rate with the catalyst weight, as can be seen in Table 1. This result
suggests the absence of mass transfer process.
Effect of the reaction temperature
The effect of reaction temperature on the hydrogenation activity was studied by
varying the reaction temperature (333, 343, 353, and 363 K), keeping constant the
m-dinitrobenzene concentration (0.1 M), hydrogen pressure (0.82 MPa) and the
catalyst weight (0.1 g). Fig. 6 shows the evolution of the conversion with time at
different reaction temperatures for the Pt/TiO2 catalyst. An enhancement in the
catalytic activity as reaction temperature increases can be noted. The yield of
m-phenylenediamine slightly increases with the reaction temperature.
Therefore the overall kinetics of m-dinitrobenzene hydrogenation to m-phenyl-
enediamine can be split into two rate equations derived for the one consecutive
reaction with steps shown in Fig. 7. The rate constants of each step in the
m-dinitrobenzene hydrogenation were evaluated: m-nitroaniline formation (k1) and
m-phenylenediamine formation (k2). In this case, the formulism of consecutive
reaction was employed [34]. Constants k1 and k2 progressively increase with the
Fig. 5 Evolution of the conversion with time at weight catalyst
278 H. Rojas et al.
123
Page 9
increases of the reaction temperature (Table 2). In all cases, k1 [ k2 always holds,
indicating that the m-dinitrobenzene hydrogenation occurs faster than the
m-nitroaniline hydrogenation to m-phenylenediamine. The formation of m-phenyl-
enediamine is slow because m-nitroaniline keeps the presence of nitro group in meta
position, which deactivates the benzene ring. This is due to the conversion of nitro
groups (electrons withdrawing groups) to amine groups (electrons donating groups),
which generates a decrease the electronic deficiency of the ring, therefore hinder the
reduction of the second nitro group. Similar observations were reported by
Udayakumar et al. [35]. They detected m-phenylenediamine in the reaction mixture
when m-dinitrobenzene was converted to intermediate m-nitroaniline and this may
be due to the competition between the m-dinitrobenzene and the newly formed m-
nitroaniline for the available coordination sites on the catalyst. From the rate
constants, an Arrhenius plot was obtained (Fig. 8) and the activation energy was
evaluated (Table 2). The obtained activation energy for the m-dinitrobenzene
hydrogenation to m-nitroaniline was 33.4 ± 0.4 kJ/mol, and the activation energy
for the m-nitroaniline hydrogenation to m-phenylenediamine was 39.8 ± 0.6
kJ/mol. The activation energies measured in this work are in agreement with those
Fig. 6 Evolution of the m-dinitrobenzene conversion with time at different temperatures
Fig. 7 m-Dinitrobenzene hydrogenation to m-phenylenediamine
Hydrogenation of m-dinitrobenzene to m-phenylenediamine 279
123
Page 10
usually reported for the hydrogenation of nitro compounds, (31 kJ/mol for the
nitrobenzene reduction [36], 40.5 kJ/mol for 2-nitrotoluene [37]). The m-phenyl-
enediamine formation is the rate limiting step in the m-dinitrobenzene hydrogena-
tion. Therefore, this step has higher activation energy. These results are in
agreement with some research for other polynitroaromatics: the rate of reduction of
the first nitro group is generally much more rapid than the rate of reduction of the
remaining nitro groups. In most cases, the rate of subsequent reduction is so slow
that the process is effectively stopped after the first nitro group is reduced [6].
Kinetic model
In order to identify the rate limiting step in this catalytic process, the conventional
Langmuir–Hinshelwood model (L–H) was used. The L–H procedure involves
several elementary steps in which one is the rate limiting step being the others in
quasi-equilibrium. The following form of the kinetic model, assuming a dissociative
hydrogen adsorption on reaction sites and the surface reaction as the rate limiting
step, has been used in agreement with previous results in the hydrogenation of other
nitro compounds [38].
Table 2 Rate constants at
different reaction temperatures
and activation energies
Reaction temperature k1 (mol/L s) k2 (mol/L s)
333 K 7.0 ± 0.43 9 10-5 1.2 ± 0.20 9 10-5
343 K 1.0 ± 0.21 9 10-4 4.0 ± 0.11 9 10-5
353 K 1.5 ± 0.10 9 10-4 5.0 ± 0.17 9 10-5
363 K 2.3 ± 0.22 9 10-4 6.3 ± 0.40 9 10-5
Activation energy
(kJ/mol)
33.4 ± 0.4 39.8 ± 0.6
Fig. 8 Arrhenius plot for the temperature dependence of the rate constants of m-dinitrobenzenehydrogenation
280 H. Rojas et al.
123
Page 11
As was discussed earlier, the overall reaction was considered to comprise two
consecutive reactions in this study, one leading to the formation of m-nitroaniline,
and the other leading to the formation of m-phenylenediamine. The model for two
situations of the m-dinitrobenzene hydrogenation was proposed: the first is when
only the m-nitroaniline is formed (mechanism I). This occurs at lower hydrogen
pressures (0.41 and 0.54 MPa). A second mechanism, when the m-phenylenedi-
amine is formed, this occurs at higher hydrogen pressures (0.63 and 0.82 MPa). The
models consisting of competitive adsorption between m-dinitrobenzene and
hydrogen was considered. The following steps were considered:
In mechanism I, the reaction between the adsorbed hydrogen (HS) and the
adsorbed reactive (m-DNBS) is assumed to be the limiting step reaction. In
mechanism II, the reaction between the adsorbed hydrogen and adsorbed
intermediate (m-NAS) is assumed to be the limiting step reaction. Based on the
above criteria, the rate equations (rI and rII) that best fitted the experimental data for
mechanisms I and II are compiled in Table 3, being S is the adsorption site, C is the
concentration of the substrate or the product (m-DNB, m-NA and m-PDA,
respectively), k1 and k2 are the rate constants for the mechanisms I and II,
respectively; K0 is the adsorption term, KH2 is the adsorption constants of hydrogen,
PH2 is the partial pressure of hydrogen.
In order to estimate the kinetic constants, the individual rate equations were
subjected to a nonlinear regression analysis such that the difference between the
experimental and the predicted rate has a minimum value. The sum of the residual
squares (SRS) give information about the quality of the fit of the model proposed.
The objective function to be minimized was:
SRS ¼ rexp � rtheo
� �2 ð2ÞHere, rexp is the experimental reaction rate, and rtheo is the theoretical reaction
rate. The kinetic constants in each case were calculated (Table 4). A comparison of
Table 3 Rate expressions for
the L–H mechanisms proposedLangmuir–Hinshelwood model Rate expression
Mechanism I. (m-nitroaniline formation)
H2 ? 2S $ 2HS
m-DNB ? S $ m-DNBS
2HS ? m-DNBS ? m-NAS rI ¼ k1PH2Cm�DNBð Þ= K1KH2
PH2ð Þ2
m-NAS $ m-NA ? S
Mechanism II. (m-phenylenediamine formation)
H2 ? 2S $ 2HS
m-DNB ? S $ m-DNBS
2HS ? m-DNBS $ m-NAS
m-NAS $ m-NA ? S
H2 ? 2S $ 2HS
m-NAS ? 2HS ? m-PDAS rII ¼ k2PH2Cm�NAð Þ= K2KH2
PH2ð Þ2
m-PDAS $ m-PDA ? S
Hydrogenation of m-dinitrobenzene to m-phenylenediamine 281
123
Page 12
the rates predicted by each model and the experimentally observed rates for
m-dinitrobenzene hydrogenation is shown in Figs. 9 and 10. The predicted values
are in reasonable agreement with each other.
Table 4 Rate constants for
mechanisms I and IIParameter Mechanism I Parameter Mechanism II
k1 (mol/L s) 1.63 9 10-6 k2 (mol/L s) 3.00 9 10-7
KH2(L/mol) 3.13 9 10-1 KH2
(L/mol) 2.95 9 10-2
K01 (L/mol) 1.52 9 10-1 K02 (L/mol) 2.42 9 10-1
Fig. 9 Comparison of predicted rates (mechanism I) with experimental rates for m-dinitrobenzenehydrogenation
Fig. 10 Comparison of predicted rates (mechanism II) with experimental rates for m-dinitrobenzenehydrogenation
282 H. Rojas et al.
123
Page 13
Conclusions
The m-phenylenediamine formation is influenced by the m-dinitrobenzene conver-
sion; the higher m-dinitrobenzene conversion, higher the yield of aromatic amine.
The yield to m-phenylenediamine progressively increases with the partial pressure
of hydrogen and reaction temperature. In the m-dinitrobenzene reaction, the rate
constants for each step were determined; it can be seen that k1 [ k2, so the rate
determining step is the m-nitroaniline hydrogenation to m-phenylenediamine. The
estimated values of activation energies of both consecutive reactions correspond to
the usual values of liquid phase hydrogenation of nitroaromatic compounds.
Acknowledgments The authors acknowledge to DIN-UPTC for financial support (SGI 683). RECIEND
COMPANY-Colombia, by donation of titania P-25 Lot. 41680882698.
References
1. Dovell F, Ferguson W, Greenfield H (1970) Ind Eng Chem Prod Res Dev 9:224–229
2. Downing R, Kunkeler P, Van Bekkum H (1997) Catal Today 37:121–137
3. Liu Y, Wei Z, Zhang J, Yan W (2007) React Kinet Catal Lett 92:121–127
4. Chen J, Zhang J, Zhanga J (2008) React Kinet Catal Lett 93:359–366
5. Kratky V, Kralik M, Mecarova M, Stolcova M, Zalibera L, Hronec M (2002) Appl Catal A Gen
235:225–231
6. Barrows S, Cramer C, Truhlar D, Elovitz M, Weber E (1996) Environ Sci Technol 30:3028–3038
7. Freifelder M (1971) Practical catalytic hydrogenation. Wiley, New York
8. Rylander P (1979) Catalytic hydrogenation in organic syntheses. Academic Press, New York
9. Telkar M, Nadgeri J, Rode C, Chaudhari R (2005) Appl Catal A Gen 295:23–30
10. Yingxin L, Jixiang C, Jiyan Z (2007) Chin J Chem Eng 15:63–67
11. Zhao L, Chen J, Zhang J (2006) J Mol Catal A Chem 246:140–145
12. Liu Y, Zuojun W, Zhang J (2006) Korean J Chem Eng 23:902–907
13. Yu Z, Liao S, Xu Y, Yang B (1997) J Mol Catal A Chem 120:247–255
14. Zhao S, Liang H, Zhou Y (2007) Catal Commun 8:1305–1309
15. Kluson P, Cerveny L (1995) Appl Catal A Gen 128:13–31
16. Neri G, Musolino M, Milone C, Visco A, Mario AD (1995) J Mol Catal A Chem 95:235–241
17. Andersson B, Hatziantoniou V, Schoon N (1986) Ind Eng Chem Proc Des 25:964
18. Cardenas F, Gomez S, Idriss H, Keane M (2009) J Catal 268:223–234
19. Veena L, Chandalia S (2001) Org Proc Res Dev 5:263–266
20. Rojas H, Reyes P (2006) Reac Kinet Mech Cat 88:363–369
21. Weisz P, Prater C (1954) Adv Catal 6:143–196
22. Rojas H, Borda G, Reyes P, Martinez J, Valencia J, Fierro JLG (2008) Catal Today 133:699–705
23. Hinz A, Larsson P, Skarman B, Andersson A (2001) Appl Catal B Environ 34:161–178
24. Lin B, Wang R, Yu X, Lin J, Xie F, Wei K (2008) Catal Lett 124:178–184
25. Shimizu K, Miyamoto Y, Satsuma A (2010) J Catal 270:86–94
26. Rojas H, Borda G, Reyes P, Castaneda J, Fierro JLG (2008) J Chil Chem Soc 53:1393–1397
27. Reyes P, Rojas H, Pecchi G, Fierro JLG (2002) J Mol Catal A Chem 179:293–299
28. Reyes P, Rojas H, Fierro JLG (2003) J Mol Catal A Chem 203:203–211
29. Reyes P, Oportus M, Pechi G, Frety R, Moraweck B (1996) Catal Lett 37:193–197
30. Perez R, Gomez A, Arenas J, Rojas S, Mariscal R, Fierro JLG, Diaz G (2005) Catal Today
107:149–156
31. Santra P, Priyanka S (2003) J Mol Catal A Chem 197:37–50
32. Alzaydien A (2004) J Appl Sci 4:575–578
33. Shringarpure P, Patel A (2011) Reac Kinet Mech Cat 103:165–180
34. Tjahjono M, Huiheng C, Widjaja E, Sa-ei K, Garland M (2009) Talanta 79:856–862
35. Udayakumar V, Alexander S, Gayathri V, Viswanathan B (2011) Reac Kinet Mech Cat 103:341–352
Hydrogenation of m-dinitrobenzene to m-phenylenediamine 283
123
Page 14
36. Serna P, Concepcion P, Corma A (2009) J Catal 265:19–25
37. Neri G, Musolino M, Bonaccorsi DA, Mercadante L, Galvagno S (1997) Ind Eng Chem Res
36:3619–3624
38. Aramendıa M, Borau V, Gomez J, Herrera A, Jimenez C, Marinas J (1993) J Catal 140:335–343
284 H. Rojas et al.
123
