Catalytic reactions involving sterically separated active sites

Article abstract of DOI:10.1134/S1070427215050110

The possibility of using mixtures of commercial catalysts bearing acid-base or redox sites for controlling the activity and selectivity of conversion of methanol into dimethyl ether, of these substances into desired hydrocarbons, and of low-temperature dehydroalkylation of benzene with propane was demonstrated.

Full text of DOI:10.1134/S1070427215050110

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 5, pp. 787−795. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © S.I. Abasov, Y.S. Isayeva, F.A. Babayeva, S.B. Agayeva, H.J. Ibragimov, D.B. Tagiyev, M.I. Rustamov, 2015, published in Zhurnal
Prikladnoi Khimii, 2015, Vol. 88, No. 5, pp. 744−752.
CATALYSIS
Catalytic Reactions Involving Sterically Separated Active Sites
S. I. Abasov, Y. S. Isayeva, F. A. Babayeva, S. B. Agayeva,
H. J. Ibragimov, D. B. Tagiyev, and M. I. Rustamov
Mamedaliyev Institute of Petrochemical Processes, National Academy of Sciences of Azerbaijan,
Khojaly ave, Baku, Az 1025 Azerbaijan
e-mail: feridan@rambler.ru
Received November 14, 2014
Abstract—The possibility of using mixtures of commercial catalysts bearing acid–base or redox sites for control-
ling the activity and selectivity of conversion of methanol into dimethyl ether, of these substances into desired
hydrocarbons, and of low-temperature dehydroalkylation of benzene with propane was demonstrated.
DOI: 10.1134/S1070427215050110
The development of processes for producing a source
of hydrocarbons and motor fuels alternative to crude oil
and based on natural gas (via syngas and methanol) and
involvement of casinghead gas components (propane,
butane) into such processes is a topical scientific
and technical problem. The flowsheet of methanol
conversion into fuels (MtSynfuels) includes steps of
methanol conversion into dimethyl ether (MtDМE) and
olefin (MtO), and also of conversion of low-molecular-
mass olefins into motor fuels [1]. It is known that the
MtSynfuels steps are accompanied by reactions of the
intermediates and products formed both with the reactant
and with each other. The drawback of the MtSynfuels
implementation in which MtO in combined with the
subsequent conversion of olefins into distillate (СОD)
is the presence of excess amounts of restricted aromatic
hydrocarbons in the resulting fuel [1]. Low conversion
of syngas into methanol in one pass over the catalyst also
restricts the development of MtSynfuels. This drawback
is eliminated by combining the methanol formation with
its irreversible conversion into dimethyl ether (DME) in
one reactor by contacting the syngas with appropriate
mechanical mixtures of catalysts or with a polyfunctional
catalyst exhibiting the required properties.
In cases when the product of one catalytic process
(primary product) is the raw material for another process
(final product), it becomes necessary to combine these
reactions in a common reaction space. This result can
be reached by using either mechanical mixtures of
catalysts or polyfunctional catalysts combining the
required catalytic properties. In contrast to polyfunctional
catalysts, localization of active sites of different nature on
separate components of a mechanical mixture of catalysts,
conventionally termed spatially separated sites, can allow
considerably simpler solution of the problem by choosing
appropriate commercially available catalysts.
Mechanical mixtures of catalysts are considered
by researchers, but mainly for comparison with
polyfunctional catalysts [2–6]. The possibility of
controlling the formation of final products or their
distribution by replacing components of the mechanical
mixture was not given due attention.
Here we consider the possibility of using mechanical
mixtures of catalysts for controlled conversion of
methanol and low-molecular-mass alkanes.
EXPERIMENTAL
On the other hand, such passing from methanol to
DME gives rise to the problem of passing from MtO to
DМEtО and from MtSynfuels to DМEtSynfuels, and
also of controlling the M/DME ratio, because methanol is
also demanded as raw material for many other processes.
Experiments were performed with mechanical catalyst
mixtures (CMs) consisting of H forms of zeolites Y
and TsVK (structural analog of ZSM-5) and of a metal
oxide component. As metal oxide components we used
787

788
C, %
ABASOV et al.
The starting reactants (methanol, n-butane, propane,
benzene) were >99% pure.
The catalytic properties of CMs were studied in a flow-
through reactor at 150–450°С, atmospheric pressure, and
feed space velocity of 1–10 h–1 for liquid and 350–500 h–1
for gas.
When performing experiments with a С6Н6 : С3Н8 =
1 : 9 mixture, we used two methods of feeding the
reactants: by bubbling and by feeding benzene in
calculated amounts with a dosing pump into a vaporizer–
mixer arranged before the reactor. Prior to experiments,
the catalyst was treated with air at 400°С (1 h).
SV, h–1
Fig. 1. Influence of the space velocity SV on the methanol
converson on the P2O5/HY catalyst at (1) 260 and (2) 300°С.
(C) Conversion.
The reaction products were analyzed by
chromatography. The yield of the reaction products was
calculated in percents relative to the total amount of
carbon atoms participating in the process.
aluminum–platinum–rhenium (APRC) and zirconium–
magnesium catalysts prepared by the procedures
described in [6, 7], respectively.
RESULTS AND DISCUSSION
The Pt,ReOx/Al2O3 catalyst was prepared by the
adsorption procedure (a) [4]. Onto spherical γ-Al2O3
preliminarily calcined at 750°С, H2PtCl6 and NH4ReO7
were deposited from aqueous solutions by method (a).
The samples were filtered, dried at 80 and 120°С, and then
calcined at 750°С for 3 h. The amount of the deposited
substances was determined from the difference between
their concentrations in the initial and final solutions. The
platinum and rhenium content of the ready catalyst was
0.3 and 0.5 wt %, respectively.
Dehydrative dimerization of methanol. The possible
use of DME as environmentally clean energy source
suggests sharp increase in the volume of its production.
Combining the production of methanol with its
dehydration into DME allows the syngas conversion
in one pass over the catalyst to be increased from 15
(СH3OH production) to almost 90% [8]. A mechanical
mixture consisting of catalysts for methanol production
from syngas and for its dehydration into DME is used for
this purpose [9, 10]. Taking into account the acid nature
of the catalysts for dehydration of alcohols into ethers, we
used for methanol dehydration HY and НTsVK zeolite-
containing catalysts.
The Mg–Zr catalyst based on TsVK zeolite was
prepared by successive impregnation with solutions of
Zr and Mg nitrates, followed by evaporation, mixing
with aluminum oxide, forming, and heat treatment at
120, 350, and 550°С for 4 h at each temperature. Catalyst
composition, %: 2.5 Zr, 2.5 Mg/HTsVK, 25 Al2O3.
As seen from Table 1, the methanol conversion of
HTsVK is accompanied by the formation of mainly
hydrocarbon products, but the catalyst is unstable, and at
360°C in 30 min its activity decreases from 75.6 to 8%.
The results of using the catalyst prepared from wide-pore
zeolite Y also appeared to be unsatisfactory.
The Н forms of the zeolites were prepared from the Na
form of the commercial catalysts. The H forms of zeolites
Y and TsVK (produced by the All-Russia Research
Institute of Petroleum Processing) were prepared via ion
exchange by threefold treatment of the initial zeolites
with a 2 M NH4Cl solution at 80°С, followed by washing
to remove Cl– ions and calcination at 350–450°С (4 h).
The zeolites were formed with a binder, alumina gel
(25 wt % Al2O3).
Despite the stability, the selectivity of this catalyst with
respect to both DME and hydrocarbons appeared to be low.
The positive results in methanol conversion are obtained
with zeolite catalysts impregnated with phosphoric acid.
As seen from Table 1, the HTsVK catalyst in this case
becomes stable with respect to conversion of methanol
into hydrocarbons, and it is possible to develop on the
basis of zeolite Y a catalyst exhibiting high activity and
selectivity in methanol dehydration into DME. As seen
from Fig. 1, theY-containing catalyst preserves its activity
Someofthezeolitecatalystsobtainedwereimpregnated
with an H3PO4 solution of preset concentration, which
was followed by the above-described heat treatments. The
phosphorus content of the samples was 5 wt % counting
on P2O5.
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CATALYTIC REACTIONS INVOLVING STERICALLY SEPARATED ACTIVE SITES
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Table 1. Methanol conversion on zeolite-containing catalysts modified with H3PO4 (T = 300°C, SV = 4 h–1)
Reaction mixture composition, % C
Time, min
СН4
∑С2+=
∑С2+
СН3ОН
DME
НY + Al2O3
15
1.7
14.8
16.5
5.7
4.5
56.5
55.8
21.3
21.6
120
1.6
HTsVK +Al2O3
15
2.4
60.85
21.84
10.6
7.4
24.4
92.0
120
−
−
−
5% Р2О5/HY+Al2O3
120
2.6
0.25
0.23
95.7
1.25
5% Р2О5/ HTsVK + Al2O3
15
2.8
2.5
60.75
60.8
18.1
21.6
10.6
10.8
7.8
4.3
120
even at a space velocity (SV) exceeding 10 h–1, i.e., it
exhibits high productivity, which is very important not
only for directly converting syngas into DME, but also
for the controlling M/DME by simply varying the amount
of the dehydrating catalyst loaded.
product should be shifted toward the latter, as this takes
place in the conversion of syngas into DME. Therefore,
for efficient choice of components of the mechanical
catalyst mixture for the subsequent step MtSynfuels or
DMEtSynfuels, it is necessary to understand the factors
governing formation of the primary product.
Our data show that not all the acid catalysts, even
belonging to the same group (aluminosilicates), can be
effective when synthesis of methanol and its dehydration
into DME are combined in a common reaction space. It
should also be noted that the use of catalysts based on
structural analogs of ZSM-5 as the second component of
mechanical mixture of catalysts, i.e., combination of the
methanol production from syngas and its conversion into
hydrocarbons, leads to deactivation of the first catalyst.
Hence, the catalysts for the synthesis of the primary
product in the mechanical mixture of the catalysts should
not be susceptible to the negative action of final products,
and the conversion of the primary product into the final
It follows from comparison of our results with
published data [9, 10] that selective dehydration of
methanol occurs on mesoporous aluminum oxide (specific
surface area 220 m2 g–1, mean mesopore diameter 3–5 nm
[10]) or wide-pore Y-type zeolites (micropore diameter
0.72 nm), whereas hydrocarbons are formed on ZSM-5
(0.55 nm) and narrower-pore zeolites of type SAPO-34
(0.39 nm) [11]. Hence, the yield of methanol conversion
products depends not only on the acid properties of the
catalyst, but also on its texture parameters.
Dehydrative dimerization of alcohol on Brønsted acid
sites can be described by Scheme 1.
Scheme 1.
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790
ABASOV et al.
Scheme 2.
Scheme 3.
The cyclic intermediate formed in the process
bond redistribution with the formation of a new cyclic
state corresponding to participation of three methanol
molecules in the process [12] or of a cyclic intermediate
structurally corresponding to methoxyethane [13, 14].
Decomposition of this intermediate leads to the formation
of the С–С bond of the primary hydrocarbon, ethylene:
decomposes without formation of С–С bonds into DME
and water molecules. In the systems containing wide-pore
Y-type zeolite, the DME molecules formed are removed
relatively readily, despite possible adsorption of DME
molecules on base sites denoted in Scheme 2 as Z2OZ3:
However, mutual approach of such sites with
Brønsted acid sites Z1OH increases the probability of the
In contrast to dehydrative dimerization of methanol,
primary ethylene is formed from methanol molecules
Table 2. Distribution of conversion products of methanol and DME on 5% НTsVK and 5% Р2О5/НTsVK + 5% Р2О5/HY (1 : 1)
(Т = 375°С, SV = 350 h–1, reactant : N2 = 1 : 1 by volume)
Content
CH3OH
(CH3)2O
CH3OH
(CH3)2O
Products
5% P2O5/HTsVK
5% P2O5/HTsVK + 5% P2O5/HY
Methane
Ethylene
Ethane
Propylene
Propane
DME
0.5
14
Traces
11
–
Traces
12
24
2
0.5
21
1.0
0.5
34
40.2
1.5
23
1.0
3.5
13
1.2
–
1.2
–
–
∑С4=
9
14.2
9.6
8.5
∑С4
4
18.2
19.0
0.8
19.3
16.5
18.5
1.0
∑С5+
10
7.0
Benzene
AHs
0.8
17.2
Traces
2.5
18.8
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CATALYTIC REACTIONS INVOLVING STERICALLY SEPARATED ACTIVE SITES
Y, %
791
with the participation of two sites. The ethylene formation
depends on the size parameters of the zeolite and can be
classed with structurally sensitive reactions. It should be
noted that, with a further decrease in the distance between
the acid and base sites, i.e., in going from ZSM-5 to
SAPO-17, SAPO-34, despite steric hindrance, Scheme 3
does not change essentially, and one hydroxy group of
methanol molecule in ethylene production from DME
is replaced by the hydroxy group of the water molecule.
Conversion of methanol and DME into hydrocarbons.
The contact of DME and methanol with HTsVK catalyst
modified with orthophosphoric acid leads, under equal
other conditions, to different distribution of hydrocarbon
products (Table 2).
DME : H2O
DME : H2O
DME
Fig. 2. Effect of water vapor on the distribution of DME
conversion products on (1, 2) 5% P2O5/HTsVK and (3) 5%
P2O5/HTsVK at Т = 450°С, SV = 1 h–1. (Y) Product yield.
(а) С2H4, (b) C3H6, (с) ΣC4H10, (d) ΣC5+, and (e) AHs.
Comparison of the products of DME conversion with
those of methanol conversion on 5% Р2О5/НTsVK shows
that, in the first case, hydrocarbons of higher molecular
mass, ∑С5+, and aromatic hydrocarbons (AHs), except
benzene, are formed, i.e., in this case primary hydrocarbon
intermediates undergo deeper oligomerization.
conditions and catalysts, i.e., is kinetically controlled.
The use of a mixture of acid catalysts leads to the
predominant occurrence of МtO/DМEtO. However,
owing to the presence of reactive intermediates formed
in transformations of methanol into DME and primary
ethylene, more efficient activation of low-molecular-
mass hydrocarbons, e.g., propane and butane, is also
possible. The conversion of methanol–butane mixtures
on a mechanical mixture of catalysts with ZSM-5 zeolite
as one of the components [4, 5] is a model for such
transformations.
The products of methanol and DME conversion
on P2O5/НTsVK differ essentially from those formed
on contact of methanol and DME with a mechanical
mixture consisting of phosphated НTsVK and НY. As
follows from Table 2, in the presence of P2O5/НY the
main products of methanol conversion are С2–С4 olefins
whose yield reaches almost 80%. However, the DME
transformations are not appreciably influenced by the
presence of P2O5 in НY. The above-noted difference in
the products of transformation of these substances may
be due to different content of water vapor in the reaction
medium in conversion of methanol and DME. Indeed,
as seen from Fig. 2, introduction of an additional portion
of water corresponding to the water amount released in
methanol conversion makes the composition of DME and
methanol conversion products closer.
Preliminary experiments showed that individual
n-butane underwent no transformations on P2O5/НTsVK
at temperatures of up to 400°С. In the temperature
interval 400–450°С, the individual n-butane transforms
into aromatic and С1–С4 hydrocarbons. The n-С4Н10
conversion does not exceed 10% in this case.
The catalyst Mg,ZrO2/Al2O3 also exhibited low
activity in conversion of individual n-butane in the
temperature interval 350–450°С. The conversion
of individual butane reaches 7%, with the product
distribution varying from С1–С5 to predominant
formation of aromatic hydrocarbons.
The DME conversion on the mechanical mixture of
phosphated zeolites under equal other conditions yields
considerably lower amount of hydrocarbons containing
more than four carbon atoms and especially of aromatic
hydrocarbons. These data also show that, under the action
of water and second zeolitic component, the conversion
of both methanol and DME can be shifted toward МtO
and DМEtO.
Methanol on this catalyst in the same temperature
interval without n-butane is converted to DME with up
to 25–40% degree of conversion.
The observed distribution of methanol and DME
conversion products (simultaneous occurrence of
the oligomerization, disproportionation, alkylation,
isomerization, etc.) is controlled by the reaction
The results of conversion of the СН3ОН : n-С4Н10 =
1 : 2 mixture on the mechanical catalyst mixture
P2O5/НTsVK + Mg,ZrO2/Al2O3 (1 : 1 by weight) are
shown in Fig. 3. As can be seen, the conversion of the
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ABASOV et al.
Table 3. Influence of temperature on the conversion of the С6Н6 : С3Н8 = 1 : 9 mixture (APRC + HY, SV = 500 h–1)
Conversion, %
Product yield, % C
T, °C
С6Н6
С3Н8
С3Н6
С1–С2
IPB
n-PB
AHs
180
200
250
300
320
350
375
400
450
1
–
–
0.3
0
0
0
0
0
0
5
–
0
0
12
1.9
6.3
12.6
17.2
19.3
7.9
7.1
3.6
0.5
2.2
5.0
11.2
15.5
6.3
2.0
0.2
0.4
1.4
0.7
0.3
Traces
0
0
0
34.2
62.1
41.3
16.1
7.9
9.0
Traces
4.7
5.2
4.2
2.3
3.1
0
12.5
6.4
0
0
0.3
0
0.1
Traces
2.5
10.5
Traces
methanol–butane mixture on the mechanical mixture of
these catalysts is characterized by a synergistic effect.
The n-butane conversion in the temperature interval
350–450°С increases from 23 to almost 100%, and the
distribution of the transformation products depending
on the reaction conditions can be directed both toward
selective formation of low-molecular-mass olefins and
toward formation of aromatic compounds, including
high-octane gasoline components. Considering this
model reaction as an intermediate step in MtSynfuels
(dehydration of methanol; oligomerization of olefins;
alkylation of intermediates with methanol and their
isomerization; etc.), we can note that the selective
formation of the desired hydrocarbon products depends
on the components of the mechanical mixture of the
catalysts. Therefore, formulation of mechanical mixtures
using catalysts with known properties can considerably
facilitate solution of the problem.
The results of these studies concern problems
related to the development of alternative hydrocarbon
fuels, MtSynfuels/DMEtSynfuels [1]. Analysis of the
results obtained and of published data suggests that
it is appropriate to perform such process in steps: to
implement MtО/DMEtО in the first step and then to
subject the dried products to selective conversion into
the distillate using mechanical mixtures of commercially
available oligomerization and isomerization catalysts.
Reactions in which the activation of hydrocarbons occurs
via intermediate states are possible in such cases. The
reaction of benzene with propane is among such reactions.
Y, %
Low-temperature dehydroalkylation of benzene with
propane and dehydrogenation of propane. The reaction
of propane with benzene occurs on a mechanical catalyst
mixture (MCM) whose components are unreduced
APRC (analog of catalyst for reforming of straight-run
naphthas) and the Н form of the zeolite. These catalysts
bear spatially separated redox and acid–base sites.
T, °C
Studies of both individual and joint transformations
of benzene and propane at temperatures of up to 450°С
on the Н forms of zeolites Y and TsVK show that
these zeolites do not activate any transformations of
Fig. 3. Influence of temperature T on the yield Y of conversion
products of CH3OH : С4Н10 = 1 : 1 (mol) mixture on Zr,Mg/
Al2O3 + HZSM-5 catalyst at SV = 500 h–1. (1) Conversion,
(2) C1–C3, (3) C2–C4, (4) C5+, (5) C6H6, and (6) AHs.
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CATALYTIC REACTIONS INVOLVING STERICALLY SEPARATED ACTIVE SITES
793
Table 4. Effect of zeolitic component on the conversion of C6H6 and C3H8 and yield of conversion products of the C6H6 : C3H8 =
1 : 9 mixture on APRC + zeolite, SV = 500 h–1
Conversion, %
Product yield, %
C3H8
Conversion, %
Product yield, %
C3H6
Zeolite
C6H6
C3H8
C6H6
C3H6
IPB
AHs
IPB
AHs
320°С
375°С
Y
62.1
43.7
12.6
16.0
12.5
8.6
5.0
8.4
6.1
4.5
0.3
1.5
15.5
22.5
0.3
1.5
15.5
22.5
4.5
4.7
TsVK
the reactants. The conversion of propane on APRC
and mechanical mixtures of APRC with one of the H
forms of the zeolites occurs similarly, and at 300–400°С
small amounts of С2Н4 and С4Н8 (propylene metathesis
products) and also of hydrogen are formed, suggesting
the propane dehydrogenation.
that acid–base sites are required for the process to occur.
Hence, presumably, activation of the catalytic system is
associated with the formation of redox sites on APRC.
The temperature dependence of the IPB and
propylene formation (Table 3) in transformations of
the С6Н6 : С3Н8 = 1 : 9 mixture on MCM suggests the
competition of two processes: formation of products
of low-temperature dehydroalkylation of benzene with
propane and dealkylation of IPB, i.e., formation of
the propane dehydrogenation product. The absence of
С1–С2 hydrocarbons suggests that the AH formation
occurs via IPB isomerization. The hydrogen release in
these transformation reflects the whole set of the above
reactions and independently characterizes the reactivity
of the С6Н6 : С3Н8 mixture in contact with MCM.
Addition of small amounts (e.g., 10 mol %) of
benzene to propane leads to the propane activation and
formation of hydrogen, whose yield corresponds to the
molar conversion of propane. As seen from Table 3,
even at temperatures as low as 180–200°С, benzene and
propane react on the mechanical mixture of the catalysts
to form isopropylbenzene (IPB). The temperature
elevation influences the conversion of the reactants
ambiguously: Up to 375°С, the propane conversion grows
monotonically, and at higher temperatures it decreases;
the benzene conversion increases as the temperature is
increased to 320°С, decreases in the interval 320–400°С,
and then increases again, but in this case methane
and ethane appear in the reaction products instead of
hydrogen. Such transformations of С6Н6 : С3Н8 are
similar to those described in [3, 4]; therefore, hereinafter
we will consider only the transformations of this mixture
at temperatures lower than 400°С.
Figure 5 shows the curves describing the rate of hy-
drogen evolution in conversion of the benzene–propane
mixture on MCM subjected to regeneration treatment
with air. These results show that the hydrogen formation
is preceded by the period when the catalysts reach the
operation activity. In the first minutes of the experiment,
С, Y, %
Depending on temperature, the distribution of С6Н6 :
С3Н8 transformation products is characterized by changes
in the yields of IPB, n-propylbenzene (n-PB), sum of other
aromatic hydrocarbons, and propylene. The yield of IPB
and AHs correlates with the temperature dependence of
the benzene conversion, and the propylene yield sharply
increases in the interval 320–375°С, when the benzene
conversion decreases.
The start and progress of the reaction are preceded
by the period in which the catalyst reaches the operation
activity level (Fig. 4). Individual treatment of the zeolite
components of MCM with ammonia leads to inhibition of
the С6Н6 : С3Н8 mixture conversion but does not affect the
conversion of propane into С2Н4 and С4Н10, suggesting
τ, min
Fig. 4. (1) C3H8 conversion K and yield Y of (2) IPB and
(3) C3H6 as functions of time τ. Т = 225°С, С3Н8 : С3Н6 = 9 : 1.
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ABASOV et al.
V, mmol g–1
DHA of benzene or direct the process toward increasing
propylene yield.
Returning to the consideration of the role of benzene
in the process, we can assume that it acts not only as re-
actant but also as agent transferring protons from the acid
component of the catalytic system to redox sites ofAPRC.
Hence, probably, the occurrence of transformations in
such mixtures depends on the time of the existence of
the intermediate benzonium ions and thus on the distance
between the redox and acid–base sites. Therefore, for
the conversion of С6Н6 : С3Н8 mixtures, it seems more
efficient to use polyfunctional catalysts whose phase
composition corresponds to MCM. Nevertheless, our
results demonstrate the possibility of improving the fuel
composition when performing MtSynfuels/DMESyn-
fuels or producing propylene (MtP process) on spatially
separated active sites.
τ, min
Fig. 5. Rate of hydrogen evolution V as a function of time
τ of contact of the C6H6 : C3H8 = 1 : 9 mixture. Т = 250°С,
SV = 500 h–1. (1) APRC + НZSM-5 and (2) APRC + НY.
neither products of conversion of the С6Н6 : С3Н8 mixture
nor hydrogen are formed. However, carbon dioxide and
water molecules are formed in this period of contact of
С6Н6 : С3Н8 with CM. The formation of these molecules
sharply decreases by the 5th–7th minute of the experi-
ment and virtually ceases by the 15th–20th minute. These
periods of the experiment are characteristic of the onset
of hydrogen detection and attainment of the maximal rate
of its evolution (Fig. 5).
CONCLUSIONS
(1) The use of a mechanical mixture of catalysts
bearing spatially separated active sites of different nature
allows reactions occurring via not only stable but also
unstable intermediates to be combined in a common
reaction space.
(2) The possibility of using mechanical catalyst
mixtures for increasing the conversion of primary
products into desired final products and for controlling the
product composition was demonstrated by the example of
methanol transformations (МtDМЕ, МtO, MtSynfuels)
and of DMEtO and DMЕtSynfuels processes.
The activation of the catalyst mixture is associated
exclusively with the reaction of propane with APRC,
and the formation of carbon dioxide and water is due to
partial reduction of the metal component of this catalyst
mixture [15].
(3) Implementation of the processes on spatially
separated active sites opens prospects for using
commercially available catalysts as components of
mechanical catalyst mixtures.
The results of experiments with other zeolitic com-
ponents showed that, on replacement of zeolite Y by,
e.g., HTsVK the relationships of the conversion of the
С6Н6 : С3Н8 mixture on MCM in the temperature inter-
val 200–400°С do not change. The benzene and propane
conversions and the yields of the transformation products
of the С6Н6 : С3Н8 = 1 : 9 mixture in relation to the type
of the H-zeolite component of CM at temperatures cor-
responding to the maximal yields of IPB (320°С) and
propylene (375°С) are given in Table 4. As can be seen,
the propane conversion increases in going from HY to
HTsVK irrespective of the extent to which benzene is
involved in the process. The propylene yield varies in
the same order. Table 4 shows that formation of the DHA
and DH products depends on the kind of the zeolitic
component.
REFERENCES
1. Lapidus, A.L., Krylov, I.F., Zhagfarov, D.G., and and
Emel’yanov, V.E., Al’ternativnye motornye topliva
(Alternative Motor Fuels), TsentrLitNefteGaz, 2008,
pp. 107–123.
2. Koval’, L.M., Bolotov, V.V., Zhukova, N.V., et al., Russ.
J. Appl. Chem., 2005, vol. 78, no. 5, p. 769.
3. Safronova, S.S., Koval’ L.V., Chernov, E.B., et al., Russ.
J. Phys. Chem. A, 2005, vol. 79, no. 1, p. 47.
4. Bragin, O.V., Vasina, T.V., and Isaev, S.A., Izv. Akad. Nauk
SSSR, Ser. Khim., 1987, p. 1682.
5. Isaev, S.A., Vasina, T.V., and Bragin, O.V., Izv. Akad. Nauk
SSSR, Ser. Khim., 1991, p. 2228.
Therefore, the use of modified zeolites or other
objects containing acid–base sites as support can improve
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 88 No. 5 2015

CATALYTIC REACTIONS INVOLVING STERICALLY SEPARATED ACTIVE SITES
795
6. Smirnov, A.V., Mazin, E.V., Yuschenkov, V.V., et al.,
11. Rustamov, M.I., Piriyev, N.N., and Babayeva, F.A., Khim.
Tekhnol. Topl. Masel, 2010, no. 1, p. 45.
J. Catal., 2000, vol. 194, p. 266.
7. Babayeva, F.A., Abasov, S.I., and Rustamov, M.I., Katal.
Prom–sti., 2009, no. 6, p. 21.
12. Khadzhiev, S.N., Kolesnichenko, N.V., and Ezhova, N.N.,
Petrol. Chem., 2008, vol. 48, p. 325.
8. Agaeva, S.B., Abasov, S.I., Tagiev, D.B., et al., Russ. J.
Appl. Chem., 2013, vol. 86, no. 5, p. 786.
13. Jackson, J.E. and Bertsch, F.M., J. Am. Chem. Soc., 1990,
vol. 112, p. 9085.
9. Popov, I.G., Reshetnyak, L.F., Shmelev, A.S., and
14. Tajima, N., Tsuneda, T., Toyama, F., and Hirano, K., J. Am.
Chem. Soc., 1998, vol. 120, p. 8222.
Sobolevskii, V.S., Khim. Prom–st., 2000, no. 7, p. 29.
10. Xu, M., Lunsford, J.H., and Goodman, D.W., Appl. Catal.,
15. Abasov, S. I., Babayeva, F.A., and Zarbaliyev, R.R., Appl.
Catal. A: General, 2003, vol. 251, p. 267.
1998, vol. 167, p. 23.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 88 No. 5 2015