Acetylene Hydrogenation to Ethylene in a Hydrogen-Rich Gaseous Mixture on a Pd/Sibunit Catalyst

Article abstract of DOI:10.1134/S0023158419040165

Abstract: The reaction of the gas-phase hydrogenation of acetylene on a Pd/Sibunit catalyst was studied depending on the H₂ : C₂H₂ molar ratio, the process temperature, and the presence of carbon monoxide. It was shown that for the reaction mixture of the composition H₂ : C₂H₂ < 20, the reaction rate depends on the hydrogen concentration and does not depend on the acetylene concentration, although for the ratio H₂ : C₂H₂ > 20, on the contrary, the order in hydrogen becomes zero and the reaction rate is determined by the acetylene content in the reaction mixture. It was found that an increase in the reaction temperature (from 30 to 85°C) leads to an increase in the contribution of complete hydrogenation to ethane. The introduction of CO into the reaction mixture up to a molar ratio of CO : C₂H₂ = 0.1 is accompanied by the almost complete blocking of the C₂H₄ readsorption sites, which results in a sharp increase in ethylene selectivity from 4 to 73%. With a further increase in the CO : C₂H₂ ratio, the number of sites available for hydrogen adsorption gradually decreases, and, correspondingly, the conversion decreases.

Full text of DOI:10.1134/S0023158419040165

ISSN 0023-1584, Kinetics and Catalysis, 2019, Vol. 60, No. 4, pp. 446–452. © Pleiades Publishing, Ltd., 2019.
Russian Text © The Author(s), 2019, published in Kinetika i Kataliz, 2019, Vol. 60, No. 4, pp. 479–485.
Acetylene Hydrogenation to Ethylene in a Hydrogen-Rich Gaseous
Mixture on a Pd/Sibunit Catalyst
D. A. Shlyapina, D. V. Glyzdovaa, T. N. Afonasenkoa, *, V. L. Temereva, and P. G. Tsyrul’nikova
aInstitute of Hydrocarbon Processing, Siberian Branch, Russian Academy of Sciences, Omsk, 644040 Russia
*e-mail: atnik@ihcp.ru
Received December 20, 2018; revised January 28, 2019; accepted February 4, 2019
Abstract—The reaction of the gas-phase hydrogenation of acetylene on a Pd/Sibunit catalyst was studied depend-
ing on the H2 : C2H2 molar ratio, the process temperature, and the presence of carbon monoxide. It was shown
that for the reaction mixture of the composition H2 : C2H2 < 20, the reaction rate depends on the hydrogen con-
centration and does not depend on the acetylene concentration, although for the ratio H2 : C2H2 > 20, on the con-
trary, the order in hydrogen becomes zero and the reaction rate is determined by the acetylene content in the reac-
tion mixture. It was found that an increase in the reaction temperature (from 30 to 85°C) leads to an increase in the
contribution of complete hydrogenation to ethane. The introduction of CO into the reaction mixture up to a molar
ratio of CO : C2H2 = 0.1 is accompanied by the almost complete blocking of the C2H4 readsorption sites, which
results in a sharp increase in ethylene selectivity from 4 to 73%. With a further increase in the CO : C2H2 ratio, the
number of sites available for hydrogen adsorption gradually decreases, and, correspondingly, the conversion
decreases.
Keywords: acetylene, ethylene, hydrogenation, Pd/Sibunit, catalytic properties
DOI: 10.1134/S0023158419040165
INTRODUCTION
stages of oxidative pyrolysis of raw materials, absorp-
tion of acetylene by solvent, liquid-phase hydrogena-
tion of acetylene to ethylene, and subsequent oligom-
erization to produce С6–С11 hydrocarbons with a high
octane number [9, 10]. The acetylene content in the
products of oxidative pyrolysis of natural gas is 8–
10%, a hydrogen content is up to 55%, and CO con-
tent is up to 28% [11].
Earlier, we carried out studies related to the liquid-
phase hydrogenation of acetylene-rich gas mixtures on
palladium catalysts supported on graphite-like carbon
material Sibunit [12–17]. Compared to Al2O3, Sibunit
does not contain acid sites that promote the side reac-
tion of acetylene oligomerization. These studies have
shown the possibility of achieving high selectivity to
ethylene under conditions where the composition of
the reaction gas mixture itself contributes to the course
of exhaustive hydrogenation reactions (the main com-
ponent of the gas mixture is hydrogen) and oligomeri-
zation (high acetylene content in the mixture (2–4 vol %
or higher)) by introducing modifying metals and car-
bon monoxide into the reaction mixture.
Currently, the production of ethylene is an import-
ant task, since ethylene serves as a feedstock in petro-
chemical polymerization processes, and is also used to
produce various industrial products (acetaldehyde,
ethylene oxide, acetic acid, etc.) [1–3]. In industry,
ethylene is produced mainly by the pyrolysis of oil
products (ethane, С3–С4 hydrocarbons, straight-run
gasoline, etc.) [4, 5]. The small amounts of acetylene
(<2 vol %) is also formed during the pyrolysis and has
an irreversible deactivating effect on catalysts, which
used in the subsequent stages of ethylene processing
[6–8]. The most important industrial method for
removing traces of acetylene is the process of gas-phase
selective hydrogenation by which the concentration of
acetylene in ethylene can be reduced to an acceptable
level (<10 ppm). In this case, the reaction mixture con-
tains a relatively small amount of hydrogen (no more
than 22 mol %) in order to avoid the involvement of eth-
ylene in the hydrogenation reaction [8].
Hydrogenation of gas mixtures enriched in acety-
lene and hydrogen in which acetylene is not an impu-
rity, but the main component that needs to be quanti-
Thus, the gas-phase hydrogenation of acetylene is
tatively converted into ethylene, is also of great scien- used to remove its impurities from ethylene, while the
tific and practical interest. This process is a key step in liquid-phase hydrogenation allows converting more
a promising gas-to-liquid (GTL) pilot technology for concentrated mixtures with respect to acetylene with a
processing light hydrocarbons of natural or oil-associ- significant excess of hydrogen. From a practical point
ated gas into more valuable products, including the of view, it is of interest to hydrogenate gas mixtures
446

ACETYLENE HYDROGENATION TO ETHYLENE
447
enriched in acetylene and hydrogen in the absence of normalization by the areas of the corresponding peaks
a solvent in a wide range of С2Н2 : Н2 ratios. There-
fore, the goal of this work was to study the process of
selective hydrogenation of mixtures enriched in acety-
lene in the gas phase, depending on the composition of
the reaction mixture, the reaction temperature, and
the presence of CO. Palladium on Sibunit was used as
a catalyst, which worked well in the liquid-phase vari-
ant of the process.
in the chromatogram:
NC H (IRM) − NC H (ORM)
2
2
2
2
X =
100%,
100%,
100%,
NC H (IRM)
2
2
N
C2H4
SC H
=
=
2
4
NC H + NC H
+ 2N
C4+
2
4
2
6
N
C2H6
SC H
2
6
+ 2N
6
NC H + NC H
C4+
2
4
2
EXPERIMENTAL
Catalyst Preparation
S
= 100 − SC H − SC H ,
C4+
2
4
2
6
The carbon composite Sibunit (pilot production of
the Institute of Hydrocarbon Processing, Siberian
Branch, Russian Academy of Sciences), which was
preliminarily treated with 5% nitric acid to increase
the number of oxygen-containing functional groups,
which are the sites of palladium chemisorption, was
used as a support. The specific surface area of the
Sibunit was 320 m2/g. To prepare the catalyst, a sup-
port fraction of 0.07–0.09 mm was used.
Palladium was supported on the Sibunit in an
amount of 0.5 wt % from a solution of Pd(NO3)2 by
incipient-wetness impregnation. Next, the sample was
dried at 120°C for 2 h and reduced in a flow of hydro-
gen at a temperature of 500°C for 3 h.
where N is the content (in mol %) of the correspond-
ing compounds.
We took the amount of acetylene converted per
minute per one gram of the catalyst weight as a mea-
sure of the catalyst activity:
VC0 H
mcat
X
2
2
W =
,
where W is the catalyst activity (
min–1),
mL
g−1
С2Н2 cat
0
is the acetylene flow rate (in
/min), Х is
V
mL
С2Н2
С2Н2
the acetylene conversion, mcat is the catalyst weight (in
grams).
Catalytic Tests
The current concentrations of acetylene and
hydrogen needed to calculate the reaction order for
these reagents were estimated assuming a steady-state
mode in the reactor. This assumption allowed us to
equate the value of the current concentration of the
reagent to its concentration at the reactor outlet and
Catalytic tests were carried out using a setup for the
gas-phase hydrogenation of acetylene to ethylene in a
flow mode at an atmospheric pressure. A portion of
the catalyst (5–50 mg) was mixed with an inert diluent
(quartz (0.07–0.09 mm) was used to form a layer with
a volume of 1 cm3) and transferred to a flow-type glass
reactor, 20 cm long and 1 cm in diameter. The reactor
was placed in a thermostat with a given temperature.
Catalytic tests were performed in the temperature
range 30–85°С. The initial reactive gas mixture
included acetylene (2–10.5 vol %), hydrogen (89.5–
98 vol %), in some cases helium (for balance), and CO
(0.1–4 vol %). The total flow rate of the reaction mix-
ture in all experiments was 100 mL/min.
use the formula
= С0(1 – Х), where С0 is the
C
С2Н2
acetylene concentration in the IRM, X is the acetylene
conversion at the reactor outlet. The current hydrogen
concentration was calculated from the acetylene con-
version.
RESULTS AND DISCUSSION
The reaction mixture at the inlet and outlet of the
reactor (gaseous part) was analyzed on a Khromos
GKh-1000 chromatograph (Russia) equipped with a
capillary column (25 m × 0.32 mm, SiO2, the operat-
ing temperature was 60°C) and a flame ionization
detector. Nitrogen was used as a carrier gas. Sampling
of the initial reaction mixture (IRM) and the mixture
at the outlet of the reactor (ORM) was performed
alternately by switching a 6-way valve, the sampling
frequency was 35 min.
According to previously published results of trans-
mission electron microscopy [17], in a Pd/Sibunit cat-
alyst after reduction at 500°C, palladium exists in the
form of spherical metal particles, which are uniformly
distributed throughout the structure of the support.
These are characterized by a narrow size distribution with
a maximum on the distribution histogram of 6–8 nm,
and the average palladium particle size of 7.8 nm.
According to [18, 19], an increase in the size of palla-
dium nanoparticles from 2–3 to 10–20 nm contrib-
utes to an increase in the selectivity of alkyn hydroge-
nation. In this case, optimal results are achieved on
palladium nanoparticles with a size of 8–15 nm.
The acetylene conversion (Х, %) and the selectivity
to ethylene (
mers (
%), ethane (
%), and oligo-
SC H ,
SC H
,
,
2
6
%)4calculated by the2method of internal
S
C
4+
KINETICS AND CATALYSIS Vol. 60 No. 4 2019

448
W , mLC H
SHLYAPIN et al.
–1
g
cat
2
min–1
centrations, the catalyst surface is predominantly cov-
S, %
2
ered with hydrogen. Despite the lower heat of hydro-
gen adsorption on palladium (88–96 kJ/mol [20] for
hydrogen vs. 112 kJ/mol [21] for acetylene), hydrogen
is an effective competitor for adsorption on the active
sites of the Pd/Sibunit catalyst when its content of the
reaction mixture is two orders of magnitude higher
than C2H2. Under these conditions, the rate of a het-
erogeneous catalytic reaction depends on the concen-
tration of a substance deficient on the catalyst surface,
i.e. acetylene, which is indicated by a reaction order in
C2H2 of 0.6. However, with a further increase in the
concentration of acetylene, the catalyst surface cover-
age increases dramatically, and at an acetylene :
hydrogen volume ratio of 1 : 25 in the gas phase, acet-
ylene (being a more strongly adsorbed substance) dis-
places hydrogen from a larger part of the surface,
resulting in an approach to the zero order in acetylene.
300
250
200
150
100
50
100
1
2
80
60
40
20
0
3
4
0
2
4
6
8
10
C
C2H2
Changes in the С2Н2 concentration have a slight
effect on the distribution of the reaction products. As
shown in Fig. 1, the hydrogenation of acetylene occurs
with the predominant formation of the target ethylene.
Ethane is also among the reaction products and results
from the complete hydrogenation of С2Н2. Moreover,
as known from [22], the hydrogenation of acetylene is
accompanied by the hydrooligomerization processes,
as a result of which C4+ hydrocarbons—butane and
butenes—are determined by chromatography in the
gaseous reaction products. With an increase in the
content of acetylene in the initial reaction mixture
from 2 to 10.5%, the selectivity to ethylene gradually
decreases from 65 to 57%. An increase in the contribu-
tion of complete hydrogenation of acetylene to ethane
is observed as evidenced by an increase in the selectiv-
ity to ethane from 13 to 24%, while the selectivity to
hydrooligomers does not change significantly, from 22
to 19%.
Fig. 1. Effect of acetylene content in the reaction mixture
on the activity (1, W) and selectivity (2, 3,
S
;
SC H ;
2 6
C2H4
4,
) of the Pd/Sibunit catalyst. The composition of the
S
C4+
gaseous mixture, С Н (2–10.5 vol %) + Н (89.5–98 vol %),
2
2
2
Т = 35°С, m = 5 mg.
cat
Effect of Acetylene Concentration
in the Reaction Mixture
The effect of acetylene content in the reaction gas
mixture on the catalytic properties of the Pd/Sibunit
catalyst was considered for a С2Н2 concentration
range of 2–10.5 vol % in the initial gas mixture. When
choosing such an interval, we were guided by the liter-
ature data [9–11] on the acetylene content in the
product mixture of methane oxidative pyrolysis. The
results of catalytic tests are presented in Fig. 1.
As can be seen, on the dependence of catalytic
activity on the current acetylene concentration in the
reaction mixture, two areas can be distinguished. In
Effect of Hydrogen Concentration
in the Reaction Mixture
the interval
= 1–4 vol %, the reaction rate
C
С2Н2
The influence of hydrogen content in the reaction
mixture on the process of acetylene hydrogenation on
the Pd/Sibunit catalyst was studied at a constant С2Н2
content of 4 vol %. The hydrogen content varied in the
range of 50–96 vol %. To maintain the constancy of
the rate of the reactive flow, a certain amount of
helium was injected into the system (up to a balance of
100 mL/min).
increases in direct proportion to the content of acety-
lene in the gas mixture. In the range 4–10 vol %, the
rate remains almost constant. The observed inflection
point corresponds to the following composition of the
reaction mixture: H2 : C2H2 ≈ 20 : 1. Since the nature
of the dependence W = f
varies considerably with
C
С2Н2
acetylene concentration, the reaction order was deter-
mined for each of the selected concentration ranges.
According to the Van’t Hoff differential method under the
assumption that one of the reactants (in this case, hydro-
Figure 2 shows the dependence of catalytic activity
on the current concentration of hydrogen. This is a
curve similar to that obtained by varying the content of
gen) is in large excess, for the range
= 1–4 vol %, the
C
С2Н2
acetylene. Thus, in the range
= 50–80 vol %, the
CH
reaction rate increases linearly w2ith increasing hydro-
gen content. The calculation of the reaction order
indicates that this range of H2 concentrations is char-
order of reaction in acetylene is 0.6, and it is close to
zero for the range ≥ 4 vol %.
C
С2Н2
The observed dependence is likely due to the com-
petitive adsorption of acetylene and hydrogen on the acterized by a hydrogen order close to the first. When
surface of palladium. Obviously, at low acetylene con- the hydrogen content in the reaction mixture is greater
KINETICS AND CATALYSIS
Vol. 60
No. 4
2019

ACETYLENE HYDROGENATION TO ETHYLENE
449
S, %
–1
than 80%, the reaction rate practically ceases to
depend on the hydrogen concentration, and the reac-
tion order approaches zero. The observed phenome-
non, as in the case of changes in the content of acety-
lene, can be explained by the competitive adsorption
of reagents on the palladium surface. It should also be
borne in mind that the surface of palladium particles
under the reaction conditions (to varying degrees
depending on the composition of the initial mixture) is
modified by deposits of oligomerization products,
which also affect the adsorption strength of reagents
and their amount on the surface [8].
W ,mLC H
g
min–1
cat
2
2
250
200
150
100
50
100
80
60
40
20
0
1
2
4
3
Comparison of the dependences of catalytic activ-
ity on the concentration of acetylene and hydrogen
(Figs. 1 and 2) allows us to establish a general pattern:
a change in the reaction order for each of the reagents
(a bend on the curve) occurs at a molar ratio of H2 :
C2H2 ≈ 20. For the reaction mixture, the composition
of which corresponds to the ratio H2 : C2H2 < 20, the
reaction rate depends on the concentration of hydro-
gen and does not depend on the concentration of acet-
ylene. In the case of a mixture of the composition H2 :
C2H2 > 20, the opposite relationship is observed. It
can be assumed that the observed changes in the kinet-
ics of acetylene hydrogenation are due to the compet-
itive adsorption of acetylene and hydrogen on the
active sites of the catalyst, which, in turn, depends on
the ratio of these reagents in the reaction mixture. It
has been reported [23] that the hydrogenation of acet-
ylene is characterized by the first order in hydrogen
and the zero or negative order in acetylene. In this
case, the reaction order in C2H2 can vary from 0 to –1,
depending on the concentration of acetylene. The
negative order is more often manifested at high C2H2
0
40
50
60
70
80
90
100
CH , %
2
Fig. 2. Effect of hydrogen concentration in the reaction
mixture on the activity (1, W) and selectivity (2,
S
;
C2H4
3,
4,
S
) of the Pd/Sibunit catalyst. The com-
S
C2H6
;
position of thegCa4s+eous mixture, С Н (4 vol %) + Н (50–
2
2
2
96 vol %) + Не (balance), Т = 35°С, m = 5 mg.
cat
Effect of Temperature
Temperature is an important factor that has a sig-
nificant impact on both the catalytic activity and the
distribution of the reaction products. Figure 3 shows
the results of a study of the effect of temperature (from
30 to 85°C with a step of 5°C) on the catalytic proper-
ties of Pd/Sibunit. As can be seen, with an increase in
temperature from 30 to 85°C, the value of acetylene
conversion increases from 20 to 96%. In the tempera-
ture range 30–45°С, the obtained dependence is lin-
concentrations and characterizes the inhibition of the ear, and with a further increase in temperature, it is
replaced by an asymptotic approach to the 100% con-
version. The apparent activation energy Ea in the range
of 30–45°C calculated by the Arrhenius equation, is
52 kJ/mol, which indicates that the process is con-
trolled by kinetics, when the reaction rate is deter-
mined by the rate of chemical transformation. The
value of Ea of acetylene hydrogenation obtained in this
work is in good agreement with the values presented in
the literature: 12.1 kcal/mol (50.6 kJ/mol) according
to [28], 11.0 kcal/mol (46.0 kJ/mol) according to [29]
gas-phase hydrogenation by excess acetylene [24].
As mentioned above, the gas-phase hydrogenation
of acetylene is used mainly for the purification of eth-
ylene from related acetylene impurities, whose content
is 0.5–2 vol %. With a substantial excess of ethylene in
the reaction mixture, the variation of the hydrogen :
acetylene reactant ratio is limited to avoid ethylene
involvement in the hydrogenation reaction. For this rea-
son, hydrogen is introduced into the mixture (acetylene +
ethylene) in an amount not exceeding 10–20 vol % [25]. and 10.6 kcal/mol (44.4 kJ/mol) according to [30].
In this case, the H2 : C2H2 ratio is small and amounts
to 1–10 [26, 27], i.e. is in the H2 : C2H2 < 20 range,
outside of which one can observe a change in the reac-
tion orders to the reagents.
With an increase in the reaction temperature, a
decrease in the selectivity to oligomers is observed,
while the selectivity to ethane increases. According to
[18, 31], on the surface of a palladium catalyst, there
are type A and type E reaction sites, which are parts of
the accessible palladium surface surrounded by a layer
of carbon deposits. Type A sites are characterized by
small sizes; therefore, they are more likely to adsorb a
smaller acetylene molecule (3.4 Å) than ethylene (4.3 Å),
followed by hydrogenation to ethylene. Type E sites
The selectivity to the main reaction products in the
range of 50–96 vol % hydrogen concentrations
remains almost unchanged (Fig. 2). The selectivity to
ethylene is 61–63% and the selectivities to ethane and
oligomers are 19–20% and 18–19%, respectively.
KINETICS AND CATALYSIS Vol. 60 No. 4 2019

450
SHLYAPIN et al.
X, %
S, %
X, %
S, %
100
80
60
40
20
100
1
2
80
60
40
20
0
2
3
1
4
3
4
0
1
2
3
4
20
30
40
50
60
70
80
90
T, °C
CCO, %
Fig. 4. Effect of CO on the conversion (1,
) and
X
C2H2
selectivity (2,
3,
4,
S
) of the Pd/Sibunit
Fig. 3. Effect of temperature on the conversion (1,
)
S
;
SC H
;
X
C2H4
C4+
C2H2
2
6
catalyst. The composition of the gaseous mixture, С Н
2
2
and selectivity (2,
3,
4,
S
) of the
S
;
S
;
C2H6
Pd/Sibunit catalyst. TCh2eHc4omposition of thegaCs4e+ous mix-
(4 vol %) + СО (0–4 vol %) + Н (92–96 vol %), Т =
2
75°С, m = 50 mg.
ture, С Н (4 vol %) + Н (96 vol %), m = 5 mg.
cat
2
2
2
cat
thereby leading to a decrease in the catalytic activity
[33–35].
are similar to type A sites, but they are large and can
adsorb molecules of all reactants. On type E sites, eth-
ylene is hydrogenated to ethane and butadiene is con-
verted to butene and butane. With an increase in the
reaction temperature, adsorbed hydrocarbons are par-
tially desorbed from the metal surface and the proba-
bility of the appearance of larger active type E sites
responsible for the formation of ethane increases [18].
Another possible reason for an increase in the ethane
concentration in the reaction products with increasing
temperature may be the stabilization of acetylene
intermediates adsorbed in the multiplet form on the
catalyst surface, ethylidene and ethylidine [8]. The
hydrogenation of such species is known to lead to the
predominant formation of ethane [22, 32].
In this study, the effect of CO addition on the cat-
alytic properties of a Pd/Sibunit sample was studied.
The results of the catalytic tests are presented in Fig. 4.
The addition of CO to the reaction mixture in an amount
of 0.1 vol % (which corresponds to a CO : C2H2 molar
ratio of 0.03) has a significant effect on the distribu-
tion of reaction products: the selectivity to ethylene
increases from 4 to 35%, the selectivity to ethane
decreases from 80 to 53%, and the selectivity to oligo-
mers decreases from 16 to 12%. The conversion does
not change and remains at the level of 100%. The
simultaneous increase in the selectivity to the target
product in the absence of a deactivating effect from the
introduction of CO can be explained by a competitive
adsorption, in which carbon monoxide displaces eth-
ylene from the catalyst surface preventing its further
hydrogenation into ethane. A high value of acetylene
conversion suggests that the catalyst surface coverage
with acetylene still remains significant.
Effect of the Presence of СО
Carbon monoxide is an effective gas modifier for
the process of acetylene hydrogenation, which favors
selective reaction in the direction of acetylene conver-
sion to ethylene. The modifying effect of CO consists
in suppressing ethylene hydrogenation, which is asso-
ciated with the different abilities of acetylene and eth-
ylene to compete with carbon monoxide for the active
sites of the catalyst. Due to the difference in the values
of the heats of adsorption of С2Н4 and CO on palla-
dium, the displacement of ethylene from the surface
occurs and the hydrogenation of ethylene to ethane is
almost completely suppressed. At the same time, CO
adsorbed on the surface of the catalyst also decreases
With an increase in CO concentration in the reac-
tion mixture to 0.5 vol % (CO : C2H2 ≈ 0.1), due to the
high adsorption interaction with the catalyst surface,
CO begins to manifest itself as a catalytic poison,
which is accompanied by a decrease in acetylene con-
version to 70% and an increase in selectivity to eth-
ylene to 73% and oligomers to 21%. Ethane ceases to
be the main product of the reaction, its fraction in the
products does not exceed 6%. A further increase in CO
concentration in the range of CO : C2H2 = 0.1–1 has a
the number of active sites for hydrogen adsorption, significant effect only on the amount of acetylene con-
KINETICS AND CATALYSIS
Vol. 60
No. 4
2019

ACETYLENE HYDROGENATION TO ETHYLENE
451
Timofeev, K.A., Gorenie Vzryv, 2015, vol. 8, no. 1,
version, which exponentially decreases to 13%. At the
same time, an increase in selectivity to C2H4 is 3% and
is caused by a decrease in the selectivity to C2H6 at a
p. 71.
2. Belov, G.P., Catal. Ind., 2014, vol. 6, p. 266.
3. Tyurin, A.A., Eremenko, B.A., and Udalova, E.A.,
constant value of
A weak change in the distribu-
.
SΣC
4+
Bashkir. Khim. Zh., 2013, vol. 20, no. 1, p. 149.
tion of reaction products at CO : C2H2 = 0.1–1 shows
that, already at CO : C2H2 = 0.1 the sites of С2Н4 read-
sorption on which its subsequent hydrogenation to
ethane may occur are blocked. At the same time, judg-
ing from a change in conversion with an increase in the
CO : C2H2 ratio, one can assume a gradual decrease in
the number of sites available for hydrogen adsorption.
4. Mukhina, T.N., Barabanov, N.L., and Babash, S.E.,
Piroliz uglevodorodnogo syr’ya (Pyrolysis of Hydrocar-
bon Feedstock), Moscow: Khimiya, 1987.
5. Pogosyan, N.M., Pogosyan, M.D., Shapovalova, O.V.,
Strekova, L.N., and Tavanyan, L.A., Neftegazokhimiya,
2016, no. 2, p. 38.
6. Liu, X., Li, Y., Lee, J.W., Hong, C.-Y., Mou, C.-Y.,
and Jang, B.W.L., Appl. Catal., A, 2012, vol. 439, p. 8.
7. Yan, X., Wheeler, J., Jang, B., Lin, W.-Y., and Zhao, B.,
CONCLUSIONS
Appl. Catal., A, 2014, vol. 487, p. 36.
The gas-phase hydrogenation of acetylene on a
0.5% Pd/Sibunit catalyst was studied depending on
the composition of the reaction mixture, the reaction
temperature, and the presence of CO. It was shown
that, for the reaction mixture of the composition H2 :
C2H2 < 20, the reaction rate depends on the concen-
tration of hydrogen and does not depend on the con-
centration of acetylene, whereas for the ratio H2 : C2H2
> 20, the opposite relationship is characteristic. With a
high probability, the observed pattern is due to the
competitive adsorption of acetylene and hydrogen on
the active sites of the catalyst.
8. Borodziski, A. and Bond, G.C., Catal. Rev., 2006,
vol. 48, p. 91.
9. US Patent 20070191655, 2007.
10. US Patent 20070021638, 2007.
11. Lapidus, A.L., Golubeva, I.A., and Zhagfarov, F.G.,
Gazokhimiya (Natural Gas Chemistry), Moscow: Tsen-
trLitNefteGaz, 2008
12. Shitova, N.B., Shlyapin, D.A., Afonasenko, T.N., Ku-
drya, E.N., Tsyrul’nikov, P.G., and Likholobov, V.A.,
Kinet. Catal., 2011, vol. 52, no. 2, p. 251.
13. Smirnova, N.S., Shlyapin, D.A., Mironenko, O.O.,
Anoshkina, E.A., Temerev, V.L., Shitova, N.B., Ko-
chubey, D.I., and Tsyrul’nikov, P.G., J. Mol. Catal. A:
Chem., 2012, vol. 358, p. 152.
We found that with an increase in the reaction tem-
perature (from 30 to 85°C), the selectivity to ethylene
and oligomers gradually decreases, which is accompa- 14. Smirnova, N.S., Shlyapin, D.A., Shitova, N.B., Ko-
chubey, D.I., and Tsyrul’nikov, P.G., J. Mol. Catal. A:
Chem., 2015, vol. 403, p. 10.
15. Smirnova, N.S., Shlyapin, D.A., Trenikhin, M.V., Ko-
chubei, D.I., and Tsyrul’nikov, P.G., Izv. Vyssh.
Uchebn. Zaved., Khim. Khim. Tekhnol., 2015, vol. 58,
no. 7, p. 31.
16. Glyzdova, D.V., Smirnova, N.S., Leont’eva, N.N.,
Gerasimov, E.Yu., Prosvirin, I.P., Vershinin, V.I.,
Shlyapin, D.A., and Tsyrul’nikov, P.G., Kinet. Catal.,
2017, vol. 58, no. 2, p. 140.
17. Glyzdova, D.V., Vedyagin, A.A., Tsapina, A.M., Kaic-
hev, V.V., Trigub, A.L., Trenikhin, M.V., Shlyapin, D.A.,
Tsyrulnikov, P.G., and Lavrenov, A.V., Appl. Catal., A,
2018, vol. 563, p. 18.
nied by an increase in the fraction of ethane in the
reaction products. This is probably due to the appear-
ance of larger reaction sites for ethylene reabsorption
on the catalyst surface.
It is shown that, when CO is added to the reaction
mixture to have a molar ratio of CO : C2H2 = 0.1, the
sites for C2H4 readsorption are almost completely
blocked on which ethylene is further hydrogenated to
ethane, and the selectivity to ethylene increases
sharply from 4 to 73%. A further increase in the CO :
C2H2 = 0.1 ratio to 1 leads to a gradual decrease in the
number of sites available for hydrogen adsorption, and
to a regular suppression of catalytic activity.
18. Borodziski, A. and Bond, G.C., Catal. Rev., 2008,
vol. 50, p. 379.
FUNDING
19. Rassolov, A.V., Markov, P.V., Bragina, G.O., Baeva, G.N.,
Krivoruchenko, D.S., Mashkovskii, I.S., Yakushev, I.A.,
Vargaftik, M.N., and Stakheev, A.Yu., Kinet. Catal.,
2016, vol. 57, no. 6, p. 853.
This work was performed in the framework of the state
assignment of the Institute of Hydrocarbon Processing,
Siberian Branch, Russian Academy of Sciences, in accor-
dance with the Program of Basic Scientific Research of the 20. Barbov, A.V., Filippov, D.V., Merkin, A.A., and Pro-
zorov, D.A., Zh. Fiz. Khim., 2014, vol. 88, no. 6,
p. 1026.
State Academies of Sciences for 2013–2020 according to
section V. 46 (project V.46.2.5, state registration in the
EGISU NIOKTR system AAAA-A17-117021450096-8).
21. Vattuone, L., Yeo, Y.Y., Kose, R., and King, D.A.,
Surf. Sci., 2000, vol. 447, p. 1.
22. Nikolaev, S.A., Zanaveskin, L.N., Smirnov, V.V.,
Aver’yanov, V.A., and Zanaveskin, K.L., Usp. Khim.,
2009, vol. 78, no. 3, p. 248.
REFERENCES
1. Arutyunov, V.S., Savchenko, V.I., Shmelev, V.M., Se-
dov, I.V., Shapovalova, O.V., Fokin, I.G., Nikitin, A.V., 23. Pradier, C.M., Mazina, M., Berthier, Y., and Oudar,
Strekova, L.N., Tarasov, A.I., Dmitruk, A.S., and
J., J. Mol. Catal., 1994, vol. 89, p. 211.
KINETICS AND CATALYSIS Vol. 60 No. 4 2019

452
SHLYAPIN et al.
24. Temkin, O.N., Shestakov, G.K., and Treger, Yu.F., 30. Inoue, Y. and Yasumori, I., J. Phys. Chem., 1971,
Atsetilen. Khimiya. Mekhanizmy reaktsii. Tekhnologiya
(Acetylene. Chemistry. Reaction Mechanisms. Tech-
nology), Moscow: Khimiya, 1991.
vol. 75, p. 880.
31. Borodziński, A. and Gołꢀbiowski, A., Langmuir, 1997,
vol. 13, no. 5, p. 883.
32. Li, J.N., Pu, M., Ma, C.C., Tian, Y., He, J., and
Evans, D.G., J. Mol. Catal. A: Chem., 2012, vol. 359,
p. 14.
25. Bos, A.N.R. and Westerterp, K.R., Chem. Eng. Pro-
cess., 1993, vol. 32, p. 1.
26. Liu, Y., McCue, A.J., Miao, C., Feng, J., Li, D., and
33. Al-Ammar, A.S. and Webb, G., J. Chem. Soc., Faraday
Anderson, J.A., J. Catal., 2018, vol. 364, p. 406.
Trans., 1979, vol. 75, p. 1900.
27. Garcia-Mota, M., Bridier, B., Perez-Ramirez, J., and
34. Larsson, M., Jansson, J., and Asplund, S., J. Catal.,
Lopez, N., J. Catal., 2010, vol. 273, p. 92.
1998, vol. 178, no. 1, p. 49.
28. Zhang, Y., Diao, W., Williams, C.T., and Monnier, J.R.,
35. López, N., Bridier, B., and Pérez-Ramírez, J., J. Phys.
Appl. Catal., A, 2014, vol. 469, p. 419.
Chem. C, 2008, vol. 112, p. 9346.
29. Bond, G.C. and Wells, P.B., J. Catal., 1965, vol. 5,
Translated by Andrey Zeigarnik
p. 65.
KINETICS AND CATALYSIS
Vol. 60
No. 4
2019