Kinetic studies on the hydrogenation of nitrate in water using Rh/Al 2O3 and Rh-Cu/Al2O3 catalysts

Article abstract of DOI:10.1134/S0023158407060109

Liquid-phase reduction NO ₃ ^- using monometallic and bimetallic catalysts (5% Rh/Al₂O₃, 5% Rh-0.5% Cu/Al ₂O₃, 5% Rh-1.5% Cu/Al₂O₃, 5% Rh-5% Cu/Al₂O₃ and a physical mixture of 5% Rh/Al ₂O₃ and 1.5% Cu/Al₂O₃) was studied in a slurry reactor operating at atmospheric pressure. Kinetic measurements were performed for a low concentration of nitrate (0.4 × 10^-3-3.2 × 10^-3 mol dm^-3) and the temperature range 293-313 K. From the experimental data, it was found that the reduction of nitrate is first order with respect to nitrate. On the basis of the rate constants, the apparent activation energy was established using a graphic method.

Full text of DOI:10.1134/S0023158407060109

ISSN 0023-1584, Kinetics and Catalysis, 2007, Vol. 48, No. 6, pp. 823–828. © MAIK “Nauka /Interperiodica” (Russia), 2007.
Published in Russian in Kinetika i Kataliz, 2007, Vol. 48, No. 6, pp. 881–886.
MECHANISMS
OF CATALYTIC REACTIONS
Kinetic Studies on the Hydrogenation of Nitrate
1
in Water Using Rh/Al O and Rh–Cu/Al O Catalysts
2
3
2
3
I. Wito n´ ska*, S. Karski, and J. Goluchowska
.
Institute of General and Ecological Chemistry, Technical University of Lód ´z , ul. Zeromskiego 116, Lód ´z , 90–924 Poland
*
e-mail: witonska@mail.p.lodz.pl
Received July 8, 2006
–
3
Abstract—Liquid-phase reduction NO using monometallic and bimetallic catalysts (5% Rh/Al O , 5% Rh –
2
3
0
1
.5% Cu/Al O , 5% Rh–1.5% Cu/Al O , 5% Rh–5% Cu/Al O and a physical mixture of 5% Rh/Al O and
2 3 2 3 2 3 2 3
.5% Cu/Al O ) was studied in a slurry reactor operating at atmospheric pressure. Kinetic measurements were
2
3
–
3
–3
–3
performed for a low concentration of nitrate (0.4 × 10 –3.2 × 10 mol dm ) and the temperature range 293–
3
13 K. From the experimental data, it was found that the reduction of nitrate is first order with respect to nitrate.
On the basis of the rate constants, the apparent activation energy was established using a graphic method.
DOI: 10.1134/S0023158407060109
1
INTRODUCTION
ducers of consumer waters are obliged to remove
–
excessive amounts of NO ions from water.
3
With increasing population and intensive develop-
Nitrates can be removed with the use of the selective
ion exchange method and biological methods. Those
methods, however, have many drawbacks mainly con-
nected with environmental protection. One of the alter-
native methods of nitrate removal from water is their
ment of harmful policy, the amount of waste-polluted
waters is growing. The contamination particularly
poses a danger to plankton living in seas and oceans,
which provides Earth’s ecosystem with 50% of its oxy-
gen and 30 billion tons of organic substances. Water
contamination can be of chemical, physical, physiolog-
ical, and biological nature.
catalytic transformation into harmless nitrogen (N ) [2,
2
3]. However, studies of catalytic reduction of nitrates
on metallic catalysts prove the formation of ammonia
Physical contamination of water refers to changes in
color, clarity, and temperature. Physiological contami-
nation is responsible for nasty taste and smell usually
caused by chemicals such as mercaptanes, amines, sul-
fides, and phenol. Biological contamination is caused
by bacteria, viruses, and protozoans. This type of con-
tamination is responsible for certain diseases.
as a by-product, which is also dangerous. The catalytic
–
hydrogenation of NO in water involved the use of
3
noble metal catalysts [4–22]. Among these metals only
palladium catalysts have been studied widely in this
reaction. Rhodium catalysts are known as good cata-
lysts in reduction processes, too. In the face of these
facts, it is justifiable to carry out studies aimed at
Chemical contamination is common and can be of designing catalytic systems of high selectivity to N
.
2
different types. Compounds resistant to biological
The activity and selectivity can be improved by the
addition of a second metal from groups 11, 12, 13, and
decomposition are particularly harmful because they
remain present in water for a long time. These are deter-
gents, pesticides, and heavy metals. Nitrates and pre-
cursors of carcinogenic nitrosoamines [1], as well as
compounds leading to eutrophication of lakes, are also
dangerous.
1
4. Usually, copper, tin, indium, or zinc was used as a
promoting second metal [4–22]. Although many papers
connected with studies of activity and selectivity
towards nitrogen formation have been published, the
changes in the catalytic behavior as a function of the
second metal are still not fully understood and a general
reaction mechanism has not yet been proposed. To
establish a mechanism of a given reaction, kinetic stud-
ies are necessary.
Due to the fact that nitrates are harmful to human
health, certain steps have been taken. The World Health
–
Organization (WHO) set a limit of NO ion content in
3
–
3
drinking water at 50 mg NO /dm . The same level of
This paper describes kinetic studies on the hydroge-
3
nitrate concentration in consumer water is recom- nation of nitrate in water at 293–313 K using Rh and
mended by Polish and European norms. Therefore, pro- Rh–Cu on alumina catalysts. We estimated the order of
the reaction in relation to nitrate(V), which was hydro-
1
This article was submitted by the authors in English.
genated using hydrogen in abundance. The hydrogen
8
23

´
8
24
VITONSKA et al.
X, %
00
tion was conducted at 293–313 K. The mixture was
1
stirred at 1300 rpm, and hydrogen was bubbled through
3
at 0.2 dm /min. No temperature rise due to the heat of
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
2
the reaction was observed in any of the runs since the
1
reactor was operated with low nitrate concentrations
3
–3
–3
–3
(0.4 × 10 –3.2 × 10 mol dm ). No pressure control
was required since the total operating pressure in the
system was equal to atmospheric pressure. As three
phases were present in the reactor, the used system is
treated as a slurry reactor.
4
–
–
The concentrations of NO and NO ions in the
3
2
reaction mixture were measured with HPLC. Samples
of the reaction medium were taken, filtered, and ana-
lyzed using a liquid chromatograph LaChrom (Merck
Hitachi) coupled with a variable wavelength UV detec-
tor LaChrom L-7400 (Merck Hitachi). The analytical
wavelength was 210 nm. In our investigation, a Merck
C LiChrospher RP-18 (5 µm) column (250 × 4.0 mm
0
20
40
60
t, min
18
Fig. 1. Conversion of nitrates in the presence of the catalysts
(1) 5% Rh/Al O , (2) 5%Rh–0.5% Cu/Al O , (3) 5% Rh–
I.D.) was used. The water solution of octyloamine
2
3
2 3
–
3
–3
1
.5% Cu/Al O , and (4) 5% Rh–5% Cu/Al O as a function
phosphorate (5 × 10 mol dm , pH 6.3) was used as a
2
3
2 3
of time. Reaction conditions: catalyst weight 1 g, tempera-
ture 293 K, reactant CNO
mobile phase. The flow rate of octylamine phosphorate
–
3
–3
3
–
3
= 1.6 × 10 mol dm , H
2
was 1 cm /min.
+
3
(1 atm, 0.2 dm /min).
For the liquid samples, the concentrations of NH4
ions were analyzed spectrophotometrically with the use
+
3
3
of Amonia-Test (2.6–193 mg NH /dm , Merck).
4
flow was constant (0.2 dm /min) during the reaction.
From our results, we also calculated a rate constant for
the temperatures 293, 298, 303, 308, and 313 K and the
activation energy.
RESULTS AND DISCUSSION
The results of the reduction of nitrates are expressed
as conversion (X, %) and selectivities (S, %). Those
parameters were defined as
EXPERIMENTAL
Catalyst Preparation
C – C
0
X = --------------- × 100% ,
Catalysts 5% Rh/Al O and 1.5% Cu/Al O (Al O ,
Cabot, SBET = 111 m /g) were prepared from water
solutions of Rh(NO ) (a.q., National Mint of Poland)
and Cu(NO ) · 3H O (a.q., POCh Gliwice, S.A.) by
aqueous impregnation. A bimetallic catalyst 5% Rh–
.5% Cu/Al O was prepared from water solutions of
both salts by coimpregnation. The water was evapo-
rated at an increased temperature (353 K) under vac-
uum. The catalysts were dried in air at 383 K for 6 h,
calcined at 773 K for 4 h in air atmosphere, and then
reduced in hydrogen atmosphere for 2 h at 573 K.
C
2
3
2
3
2
3
0
2
C
+
4
NH
3
3
+
= --------------- × 100% ,
3
2
2
C – C
0
1
C
–
2
2
3
NO
SNO
–
2
= --------------- × 100% ,
C – C
0
SN2 = 100% – SNH4
+
– SNO
–
2
,
where SNH4
+
, SNO
–
2
, and SN2 are selectivity towards
ammonia, nitrites, and nitrogen, respectively; C is the
molar concentration of nitrates at the beginning of the
reduction; C is the molar concentration of nitrates after
0
Catalytic Measurements
The hydrogenation of the nitrate solution
–
3
–3
–3
(
1
[NaNO ] = 0.4 × 10 ; 0.8 × 10 ; 1.6 × 10 ; 3.2 × time t; CNH4 is the molar concentration of ammonia
+
3
0
−3
–3
0 mol dm (NaNO , a.q., POCh Gliwice, S.A.)) was
3
after time t; and CNO
–
2
is the molar concentration of
performed in a thermostated glass reactor equipped
with a stirrer, a hydrogen supply system, a burette, and nitrites after time t.
a pH electrode. The ammonia formed during the reduc-
Figure 1 presents changes in the conversion of
tion of nitrate was neutralized by the addition of an nitrates for a monometallic system (5% Rh/Al O ) and
2
3
–
2
–3
aqueous solution of HCl (5 × 10 mol dm ) to main- for rhodium catalysts supported on Al O and modified
2
3
tain constant pH 5.5 in the reaction medium. The reac- with copper. The supported monometallic rhodium cat-
KINETICS AND CATALYSIS Vol. 48 No. 6 2007

KINETIC STUDIES ON THE HYDROGENATION OF NITRATE IN WATER
, mol dm–3
825
CNO3
–
logCNO3
–
[ mol dm–3]
1
1
0
0
.6
.2
.8
.4
0
0
–1
–2
(
‡)
1
2
3
0.0035
(
‡)
4
3
2
1
(b)
0
0
0
.0030
.0025
.0020
–3
–4
0.0015
–
–
5
6
0
0
.0010
.0005
–
7
–
8
0
3
6
9 12 15
0
3
6
9
12 15
t, min
5
4
3
2
1
0
(
b)
t, min
–
3
–
3
Fig. 3. The concentration of NO and logarithm of NO
concentration as a function of the time of hydrogenation of
nitrate over 5% Rh–1.5% Cu/Al O at 293 K. Initial con-
2
3
–
3
centrations of NO are as follows: (1) 0.4 × 10–3 mol dm–3;
–
3
–3
–3
–3
(
1
2) 0.8 × 10 mol dm ; (3) 1.6 × 10 mol dm ; (4) 3.2 ×
0
1
1
0
0
0
.5
.2
.9
.6
.3
0
(
c)
–
3
mol dm–3.
Cu contents (Fig. 2b). For catalysts with a small amount
of copper, the presence of nitrites was not observed in
the reaction solution.
The catalytic reduction of nitrates requires the for-
mation of sufficient mono- and bimetallic sites on the
surface of bimetallic catalysts. With a greater content of
copper in Rh–Cu/Al O catalysts, the chance of form-
1
00
(
d)
8
6
4
2
0
0
0
0
2
3
ing bimetallic sites increases. Because those bimetallic
sites are active for nitrate reduction to nitrite in the case
of 5% Rh–5% Cu/Al O , more intermediate nitrites
2
3
0
10
20
30
t, min
40
50
60 were released into the reaction solution (Fig. 2b).
The formation of ammonia was low at the beginning
of the reaction over all catalysts (Fig. 2c). The lowest
amount of ammonia formation during the degradation
Fig. 2. The concentration profiles as a function of time for
–
3
–3
the reduction of 1.6 × 10 mol dm nitrate solution at
2
93 K over Rh–Cu/Al O catalysts ((1) 5% Rh/Al O , (2)
2 3 2 3
of nitrates was for the 5% Rh/Al O catalyst. The addi-
5
% Rh–1.5% Cu/Al O , and (3) 5% Rh–5% Cu/Al O ). (a)
2
3
2
3
2 3
The concentration profiles of nitrates as a function of time;
b) The concentration profiles of nitrites as a function of
tion of copper to monometallic rhodium catalysts
increased the concentration of ammonia in the reaction
mixture.
(
time; (c) The concentration profiles of ammonia as a func-
tion of time; (d) The selectivity towards N2.
Figure 2d shows the selectivity towards N in the
2
reduction of nitrates obtained for a monometallic sys-
tem (5% Rh/Al O ) and for rhodium catalysts sup-
alyst is active in the reduction of nitrates. The value of
conversion of nitrates over 5% Rh/Al O is consider-
2
3
2
3
ported on Al O and modified with copper. These
2
3
ably higher than in the case of monometallic palladium
catalysts [23, 24]. The conversion obtained for bimetal-
lic Rh–Cu/Al O catalysts is not much higher than in
results of our investigations confirm the high selectivity
of monometallic rhodium catalysts. Unfortunately, the
addition of copper to rhodium catalysts does not
increase the selectivity to N2.
2
3
the case of the monometallic system.
The reduction of nitrates via nitrites to nitrogen and
ammonia over Rh–Cu/Al O and Rh/Al O catalysts is
Figure 3b shows the logarithm of nitrate concentra-
tion as a function of different initial nitrate ion concen-
trations for 5% Rh–1.5% Cu/Al O . Those relation-
2
3
2
3
presented in Figs. 2a–2d.
2
3
The results in Fig. 2a show that the addition of cop-
per to the rhodium catalyst decreases the time that is
–
3
ships are linear for all initial concentrations of NO in
necessary for a complete reduction of nitrates. How- the first 15 min of the reaction. From this study we cal-
ever, the activity for the monometallic catalyst at the culate the rates of reaction. The logarithmic relation-
end of the run is also high.
ship between the reaction rates for the hydrogenation of
–
3
3
–
3
–3
NO and the concentrations of NO (0.4 × 10 –3.2 ×
The release of nitrites into the solution during the
–
–3
reduction of nitrate was higher for catalysts with higher 10 mol dm ) is shown in Fig. 4.
KINETICS AND CATALYSIS Vol. 48 No. 6 2007

´
8
26
logvred [mol s (g Cat) ]
VITONSKA et al.
–
1
–1
–1 –1
lnk [l mol s ]
–
–
–
–
–
–
–
5.3
5.5
5.7
5.9
6.1
6.3
–5.0
–
–
5.5
6.0
–6.5
.00315
0
0.00325
0.00335
0.00345
T, K
–
1
6.5
–
3.8
–3.6
–3.4
–3.2
–3.0
logC [mol dm ]
–2.8
–
3
Fig. 5. Arrhenius plot for the reduction of nitrates on the 5%
–
Rh–1.5% Cu/Al O catalyst. Initial concentration of NO
3
is 1.6 × 10–3 mol dm . The temperature range is 293–313 K.
2
3
Fig. 4. Dependences of the reaction rates on concentrations
of NO in the hydrogenation of NO over 5% Rh–1.5%
–
3
–
3
–3
Cu/Al O . Reaction conditions: catalyst weight 1 g, tempera-
2
3
–
3
ture 293 K, reactant NO (0.4 × 10 –3.2 × 10 mol dm–3),
–
3
–3
Tacke and Vorlop [21] determined the kinetics of
3
H (1 atm, 0.2 dm /min). The rates of the reaction (v ) were
2
r
nitrate hydrogenation over the Pd/Cu bimetallic cata-
lyst containing 5 wt % of Pd and 1.25 wt % of Cu. The
measurements were performed in a slurry reactor at
–
3
calculated for the first 15 min of NO reduction as the number
of moles of NO converted to products [mol s (g Cat)–1].
–
3
–
1
2
93 K. They found the reaction rate to be of 0.7 order
with respect to nitrate and independent of the hydrogen
From the slopes of the plots, the reaction order of partial pressure provided that this pressure is higher
NO hydrogenation was determined to be 0.7 with than about 1 bar.
–
3
–
3
Warna et al. [11] performed measurements in a
respect to the NO concentration.
metallic monolith reactor. They suggested that, in the
process of catalytic nitrate reduction, the key interme-
diate on a noble metal might be NO. According to that
mechanism, a kinetic model that accounts for a step-
wise transformation of the parent ion via different inter-
mediates to nitrogen and ammonia was derived.
The degradation of nitrates was also measured at
different temperatures (293–313 K) over 5% Rh–1.5%
Cu/Al O to define other kinetic parameters. For the
2
3
experimental data and on the basis of the fact that the
depletion of nitrate follows approximately a first order
decay, the values of rate constants were calculated
–
3
–3
Ilinitch et al. [12] claimed that NO is the key inter-
(
k = 2.1 × 10 at 293 K, k = 2.7 × 10 at 298 K, k = 4.0 ×
–
–
–3
–3
–3
1
0 at 303 K, k = 4.4 × 10 at 308 K, k = 4.6 × 10 at mediate in hydrogenation of NO and NO in the con-
3
2
3
13 K). From the slopes of the straight line in Fig. 5. the
version of NHads species on the surface.
apparent activation energy was found to be 31 kJ/mol in
the process of the liquid-phase reduction of aqueous
nitrate over the Rh–Cu bimetallic catalyst.
Pintar et al. [10] presented kinetic data on the reduc-
–
–
tion of NO and NO over Pd–Cu/Al O catalysts. The
3
2
2
3
Apparent activation energies for the monometallic kinetic data were interpreted with rate equations based
rhodium catalyst and for the physical mixture of 5% on the Langmuir–Hinshelwood mechanism. The reduc-
Rh/Al O and 1.5% Cu/Al O catalysts were estimated tion of nitrate occurs by heterolytic electron transfer
2
3
2
3
in the same way and are summarized in the table.
A large number of studies of nitrate hydrogenation
on the effects of an additive metal and support have
been reported [1–20], while only a few have been pub- about the activation energy. With the aim of gaining a
lished on the kinetics and mechanism [10–12, 21, 22].
between adsorbed reactant species on different types of
active sites.
However, in these papers no information is given
deeper understanding of the mechanism of nitrate
Rate constants of nitrate hydrogenation for different temperatures and values of activation energy
4
3
k × 10 , dm /(mol s)
Catalyst
Ea, kJ/mol
2
93 K
298 K
303 K
308 K
313 K
5
5
5
% Rh/Al O
5
6
8
9
13
14
40
14
16
44
17
17
46
44
42
31
2
3
% Rh/Al O + 1.5% Cu/Al O
3
2
3
2
% Rh–1.5% Cu/Al O3
21
27
2
KINETICS AND CATALYSIS Vol. 48 No. 6 2007

KINETIC STUDIES ON THE HYDROGENATION OF NITRATE IN WATER
827
reduction on bimetallic rhodium based catalysts, we
N2
Rh–Cu/Al O
2
3
studied the kinetics of nitrate hydrogenation over 5%
Rh/Al O , the physical mixture of 5% Rh/Al O and
Rh/Al O
Rh/Al O
2 3
2
3
NO3–
NO2–
[N]ads
2
3
2
3
1
.5% Cu/Al O , and the bimetallic catalyst containing
NH4+
2
3
also 5 wt % of rhodium and 1.5 wt % of copper. Kinetic
measurements were performed in a slurry reactor at
atmospheric pressure and at a different reaction temper- Rh/Al
In the case of using a physical mixture of the 5%
and 1.5% Cu/Al catalysts in catalytic
O
O
2 3
2
3
atures (293, 298, 303, 308, and 313 K).
measurements, the activation energy shows a value
between the ones calculated for the mono- and bimetal-
On the basis of the experimental data, we found that
lic systems, which is 42 kJ/mol. Carrying out a catalytic
–
3
–
3
the reaction order with respect to NO was about one
process of NO hydrogenation in a slurry reactor in the
for all studied catalysts. Kinetic studies carried out at
presence of a physical mixture of monometallic cata-
three different temperatures allowed calculating the lysts, one can expect the separation of its components;
activation energy for each system (table). E values pre- however, we cannot eliminate the presence of a certain
a
sented in the table show small differences of this amount of catalyst where both metallic components are
parameter determined for monometallic 5% Rh/Al O
in close contact. In such a situation, the reaction will
run in parallel according to two different mechanisms.
2
3
and bimetallic 5% Rh – 1.5% Cu/Al O systems.
2
3
The E value, however, is closer to the one obtained for
a
It is generally accepted that the hydrogenation of the 5% Rh/Al O system. Therefore, it can be assumed
2
3
–
3
–
2
that the classic catalytic mechanism is the dominant
process in this case.
NO is a consecutive reaction with NO as an interme-
–
diate product, and the hydrogenation of NO is a key
2
+
step in determining selectivity for N and NH [3, 9,
4]. In the case of Pd–Cu/Al O [10] and Pt–Cu/Al O
25] catalysts, it was shown that the first step in the
nitrate reduction is probably a redox reaction between
2
4
CONCLUSIONS
1
[
2 3 2 3
The monometallic rhodium catalyst (5% Rh/Al O )
2
3
is characterized by high activity and high selectivity
toward N in the reduction of nitrates. The addition of
–
3
2
0
Cu and NO , leading to nitrite intermediates and to an
copper insensibly increases activity but does not
oxidized form of copper. The role of noble metal is the improve the selectivity toward nitrogen.
+
reduction of nitrite to N or NH by catalytic reduction
The apparent activation energies calculated for the
2
4
mono- and bimetallic systems and also for a physical
mixture do not differ markedly.
and the activation of hydrogen, allowing the reduction of
Cu to Cu . However, monometallic palladium and plat-
2+
0
inum catalysts are inactive for nitrate reduction [10, 25].
REFERENCES
In the present study, it was shown that the monome-
tallic rhodium catalyst is active in the reduction of
1. Schidt, J. and Vorlop, K.D., Proc. Fourth Eur. Congr. on
Biotechnology, Amsterdam, 1987, vol. 1, p. 155.
–
NO , but its activity is smaller than bimetallic Rh–
3
2
. Tacke, T. and Vorlop, K.D., Dechema Biotechnology
Conf., 1987, vol. 3, p. 155.
Cu/Al O catalysts (Fig. 1). In the case of the Rh–Cu
2
3
–
3
bimetallic system, the reduction of NO can take place
3. Horold, S., Vorlop, K.D., Tacke, T., and Sell, M., Catal.
Today, 1993, vol. 17, p. 21.
4. Horold, S., Tacke, T., and Vorlop, K.D., Environ. Tech-
nol., 1993, vol. 14, p. 931.
5. Prusse, U., Lein, M., Dum, J., and Vorlop, K.D., Catal.
Today, 2000, vol. 55, p. 79.
on a mixed site, where both components of the Rh–
Cu/Al O catalyst participate in the catalytic transfor-
2
3
mation. The promoting effect of copper can be related
to its ability to reduce nitrate according to the redox
reaction. The intermediate products formed during the
process undergo further reduction on rhodium accord-
ing to a classic catalytic reaction. On the other hand, we
found that the activity of the monometallic rhodium
catalyst is also high and the studied reaction proceeds
as a classic catalytic reaction. Because of the small dif-
ferences of apparent activation energy obtained for
6. Prusse, U. and Vorlop, K.D., J. Mol. Catal., 2001,
vol. 173, p. 313.
7. Berndt, H., Monnich, I., Lucke, B., and Menzel, M.,
Appl. Catal., B, 2001, vol. 30, p. 111.
8. Batista, J., Tar, A., and Ceh, M., Catal. Lett., 1997,
vol. 43, p. 79.
monometallic and bimetallic systems, it is difficult to
9. Yoshinaga, Y., Akita, T., Mikami, I., and Okuhara, T.,
–
J. Catal., 2002, vol. 207, p. 37.
choose the appropriate mechanism of NO reduction in
3
1
0. Pintar, A., Batista, J., Levec, J., and Kajiuchi, T., Appl.
Catal., B, 1996, vol. 11, p. 81.
the presence of the 5% Rh–1.5% Cu/Al O catalyst. It
2
3
–
seems that the reduction of NO over bimetallic cata-
3
1
1. Warna, J., Turenen, I., Salmi, T., and Mauula, T., Chem.
Eng. Sci., 1994, vol. 49, p. 5763.
lysts can take place according to the following scheme:
KINETICS AND CATALYSIS Vol. 48 No. 6 2007

´
8
1
28
VITONSKA et al.
2. Ilinitch, O.M., Nosova, L.V., Gorodetskii, V.V., 18. Vorlop, K.D. and Tacke, T., Chem.–Ing.–Tech., 1989,
Ivanov, V.P., Trukhan, S.N., Gribov, E.N., Bogdanov,
S.V., and Cuperus, F.P., J. Mol. Catal. A: Chem., 2000,
vol. 158, p. 237.
vol. 61, p. 836.
1
2
9. Lecloux, A., Catal. Today, 1999, vol. 53, p. 23.
0. Tanaka, K. and Ikami, M., Top. Catal., 2002, vol. 20,
1
1
1
3. Strukul, G., Pinna, F., Morella, M., Meregalli, L., and
p. 25.
Tomaselli, M., Catal. Today, 1996, vol. 27, p. 209.
2
2
2
1. Tacke, T. and Vorlop, K.D., Chem.–Ing.–Tech., 1993,
4. Ilinitch, O.M., Cuperus, P.P., Nosoval, L.V., and Gri-
vol. 65, p. 1500.
bov, E.N., Catal. Today, 2000, vol. 56, p. 137.
2. Mikami, I., Sakamoto, Y., Yoshinaga, Y., and Okuhara, T.,
5. Matatov-Meytal,Y., Barelko, V.,Yuranov, L., Kiwi-Min-
sker, L., Renken, A., and Tuch, M., Appl. Catal., B, 2001,
vol. 31, p. 233.
Appl. Catal., B, 2003, vol. 44, p. 79.
3. Karski, S., Witonska, I., and Goluchowska, J., React.
Kinet. Catal. Lett. (in press).
1
1
6. Pintar, A., Batista, J., and Levec, J., Catal. Today, 2001, 24. Karski, S., Witonska, I., and Goluchowska, J., Pol. J.
vol. 66, p. 503.
Environ. Stud., 2005, vol. 14, p. 199.
7. Pintar, A., Sentine, M., and Levec, J., J. Catal., 1998, 25. Epron, F., Gautard, F., Pineda, C., and Barbier, J.,
vol. 174, p. 72.
J. Catal., 2001, vol. 198, p. 303.
KINETICS AND CATALYSIS Vol. 48 No. 6 2007