Volume 02 Issue 05-2022
1
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
02
I
SSUE
05
Pages:
01-06
SJIF
I
MPACT
FACTOR
(2022:
6.
108
)
OCLC
–
1121105677
METADATA
IF
–
5.582
Publisher:
Oscar Publishing Services
Servi
ABSTRACT
Products of petrochemical industries are necessary for every modern person, thousands of enterprises in various
industries. A result of the distillation of crude oil, cyclohexane ended up in naphtha, it was sent to catalytic
reformers, where it was processed into benzene. Based on the results obtained in the laboratory for the synthesis of
cyclohexane using ethylene, tests were carried out in the central laboratories Shurtan gas chemical complex. When
analyzing the resulting product using gas chromatography, it was found thatabout 17.5% cyclohexane was formed.
The technical parameters of the products (butadiene-1,3 and cyclohexane), synthesized by the staff of the National
University of Uzbekistan and the Central Laboratory of the Shurtan Gas Chemical Complex, give approximate
properties to imported cyclohexane at the JSC of the Shurtan Gas Chemical Complex.
KEYWORDS
Benzene, ethylene, cyclohexane, oil, catalyst, reaction of Dils-Alder.
Research Article
STUDY OF THE PROCESS OF OBTAINING A CATALYST FOR THE
SYNTHESIS OF BENZENE BASED ON ETHYLENE FOR THE PRODUCTION
OF CYCLOHEXANE
Submission Date:
May 01, 2022,
Accepted Date:
May 05, 2022,
Published Date:
May 10, 2022
Crossref doi:
https://doi.org/10.37547/ajast/Volume02Issue05-01
Ozoda Abdullaevna Salikhova
Candidate Of Technical Sciences, Associate Professor Of The Department Of Organic Chemistry And Heavy
Organic Synthesis, Tashkent Institute Of Chemical Technology, Tashkent, Uzbekistan
Sarvinoz Gani Qizi Shodmonova
Master Of Department Of Organic Chemistry And Heavy Organic Synthesis, Tashkent Institute Of Chemical
Technology, Tashkent, Uzbekistan
Kodirov Orif Sharipovich
Associate Professor Of National University Of Uzbekistan, Tashkent Uzbekistan
Journal
Website:
https://theusajournals.c
om/index.php/ajast
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 02 Issue 05-2022
2
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
02
I
SSUE
05
Pages:
01-06
SJIF
I
MPACT
FACTOR
(2022:
6.
108
)
OCLC
–
1121105677
METADATA
IF
–
5.582
Publisher:
Oscar Publishing Services
Servi
INTRODUCTION
Products of petrochemical industries are
necessary for every modern person, thousands
of enterprises in various industries. These are
varnishes,
paints,
solvents,
polymers,
detergents and cosmetics, medicines and much
more. Interest in cyclohexane arose in 1938 in
connection with the development of nylon by
DuPont,
which
proposed
the
use
of
cyclohexane as the preferred raw material.
After World War II, nylon production increased
by 100% per year for some time, so that the
cyclohexane contained in crude oil soon
became insufficient. The standard crude oil that
was supplied to US refineries at the time
contained 1% cyclohexane. Moreover, since as a
result of the distillation of crude oil,
cyclohexane ended up in naphtha, it was sent
to catalytic reformers, where it was processed
into benzene. And subsequently, while many
other substances were also converted to
benzene by catalytic reforming, benzene
became a good source of cyclohexane.
Cyclohexane (С6H12
) is a cycle of six carbon
atoms, each has 2 hydrogen atoms. It is similar
to benzene, but it does not have double bonds.
It is a colorless, water-insoluble and non-
corrosive liquid with a pungent odor. It is
combustible, like any product derived from oil;
it is transported in tanks, tank trucks, barges
and metal drums, which must have a red mark
adopted for flammable liquids. The industry
produces technical grade cyclohexane (purity
95% or 99%) and solvent cyclohexane (purity not
less than 85%).
Cyclohexane is also used in the Shurtan gas
chemical complex as a solvent for the
production of various grades of polyethylene.
The polymerization catalysts are dissolved in
pure
cyclohexane
and
the
ethylene
polymerization process is carried out; after the
process is completed, the cyclohexane is
recovered by distillation and returned to the
process
Based on the results obtained in the laboratory
for the synthesis of cyclohexane using ethylene,
tests
were
carried
out
in
the
centrallaboratoriesShurtan
gas
chemical
complex. Under these conditions, several
methods have been tried for the synthesis of
ethylene-based cyclohexane.
Ethylene
dimerizes
to
form
butene-1.
Triethylaluminum is used as a catalyst. The
product formed in the process is rectified, and
unreacted ethylene is returned to the original
synthesis process. The cis-, trans-butene-2 and
butadiene-1,3 formed in this process are also
separated by distillation. Purified butene-1, cis-,
trans-butene-2 is subjected to dehydrogenation
to obtain butadiene-1,3. The catalyst is
chromium (III) oxide; activated and acid-
modified Navbakhor bentonite is used as a
carrier. The resulting product is purified from
butadiene-1,3, but unreacted butenes are
returned to the process. Cyclohexene is
obtained by a 4+2 cyclocoupling reaction (Diels-
Alder reaction) based on 1,3-butadiene and
ethylene obtained by distillation. The catalyst is
aluminum chloride and aluminum oxide is used
as a carrier. The product is purified by
distillation,
the
resulting
mixture
of
cyclohexane, cyclohexadiene and benzene is
hydrogenated on a nickel catalyst to obtain
cyclohexane.
Hydrogen
is
used
for
hydrogenation formed during the synthesis of
butadiene-1,3.
In the process of synthesis of butene-1 in the
Shurtan gas-chemical complex, a mixture of
various hydrocarbons is released as a secondary
product. This mixture contains 38.0 - 42.0%
butadiene-1,3. This by-product is currently sold
as a low quality fuel. Butadiene-1,3 was isolated
from this mixture by rectification. The resulting
Volume 02 Issue 05-2022
3
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
02
I
SSUE
05
Pages:
01-06
SJIF
I
MPACT
FACTOR
(2022:
6.
108
)
OCLC
–
1121105677
METADATA
IF
–
5.582
Publisher:
Oscar Publishing Services
Servi
product is sent for the synthesis of
cyclohexane, as in the first method.
Benzene is synthesized from ethylene. At the
same time, activated and acid-modified
Navbakhor bentonite was used as a carrier, and
chromium oxide (III) was used as a catalyst.
From the mixture, benzene is purified by
distillation-extraction
(the
extractant
is
dimethyl sulfoxide) and rectification. Next,
hydrogenation of benzene is carried out, as in
the first method, and cyclohexane is obtained.
According to the first proposed method,
gaseous products obtained during the synthesis
of butene-1 based on ethylene on a granular
catalyst impregnated with bentonite, chromium
(III) oxide at atmospheric pressure at a
temperature of 550–600°C, the catalyzate was
reanalyzed by gas chromatography with a yield
of 8.74 mol. % butadiene-1.3. The resulting
product is separated by distillation with cooling,
and the remaining gas mixture is returned to
the synthesis.
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Volume 02 Issue 05-2022
4
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
02
I
SSUE
05
Pages:
01-06
SJIF
I
MPACT
FACTOR
(2022:
6.
108
)
OCLC
–
1121105677
METADATA
IF
–
5.582
Publisher:
Oscar Publishing Services
Servi
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Volume 02 Issue 05-2022
5
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
02
I
SSUE
05
Pages:
01-06
SJIF
I
MPACT
FACTOR
(2022:
6.
108
)
OCLC
–
1121105677
METADATA
IF
–
5.582
Publisher:
Oscar Publishing Services
Servi
Rete
ntion Tim
e
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2.22
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Figure 1. This flow diagram shows a process for producing cyclohexane
Reaction. Initially, benzene is fed to the primary
reactor along with fresh and recycled hydrogen. The
hydrogenation reaction is carried out in a bubble
column reactor, in the presence of a nickel catalyst.
The catalyst is maintained in a suspension with the aid
of an external circulation loop. Most of the heat of
reaction is removed by the vaporization of the
product stream, which is further recovered via a top
stream within the reactor. The remaining reaction
heat is removed in the external loop, by passing the
reactor reflux stream through a heat exchanger
against boiler feedwater, producing low-pressure
steam.
Most of the benzene feed is converted in this step.
The top gaseous product stream is directed to a fixed-
bed reactor, where the remaining benzene content is
converted
to
cyclohexane.
The
finishing
hydrogenation reaction is conducted in the presence
of a solid nickel-based catalyst supported on alumina.
Hydrogen recovery. The product stream is fed to a
knock-out drum operated at high pressure. Most of
the cyclohexane in the feed condenses, producing
two streams: one gaseous hydrogen-rich stream and a
liquid cyclohexane-rich stream. The hydrogen stream
is routed to the recycle compressor, where it is
compressed to the pressure of the primary reactor
and recycled.
Purification. In a distillation column, the liquid
cyclohexane-rich stream that is recovered is stripped
of lighter contaminants, such as methane, ethane and
soluble hydrogen. Light-ends recovered from
column’s top are used for fuel, while a cyclohexane
stream with a residual benzene content lower than
100 ppm is obtained from column’s bottom.
As a result of the research, a catalyst was synthesized
for the alkylation of benzene with ethylene based on
zeolite ZSM-5 without binders. To obtain a catalyst
mix 24 - 37 wt. % powdered zeolite ZSM-5 with 7 - 11
Volume 02 Issue 05-2022
6
American Journal Of Applied Science And Technology
(ISSN
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2771-2745)
VOLUME
02
I
SSUE
05
Pages:
01-06
SJIF
I
MPACT
FACTOR
(2022:
6.
108
)
OCLC
–
1121105677
METADATA
IF
–
5.582
Publisher:
Oscar Publishing Services
Servi
wt. % kaolin, 53 - 60 wt. % ground silica gel and 3 - 5 wt.
% of oligomeric orthosilicic acid esters. The mixture is
moistened, molded into granules by extrusion, then
dried and calcined in an atmosphere of air. Then the
granules are subjected to hydrothermal crystallization
in the reaction mixture of the composition (3,0 -
4,0)Na2O ∙ (0,5 - 2,3)R ∙ Al2O3× ×(60 - 80)SiO2 ∙ (450 -
900)H2O, washed with demineralized water, treated
aqueous solutions of ammonium salts to a degree of
substitution of Na+ cations in the zeolite at least 97 %,
again washed with demineralized water, dried and
calcined. Using the synthesized catalyst, alkylation of
benzene with ethylene is carried out at a temperature
of 400 °C, a pressure of 2,5 MPa, a mass ratio of
benzene : ethylene 18 : 1, and a bulk flow rate of
benzene of 15 h - 1. The catalyst provides a high
content (18,2 - 18,8 wt. %) of ethylbenzene in the
alkylate
By passing a mixture of purified 1,3-butadiene and
ethylene through a catalyst prepared by impregnating
aluminum chloride into activated alumina at a
temperature of 500-600°C. The product obtained by
the Diels-Alder reaction at a temperature of 280-
300°C, hydrogenation with hydrogen at a pressure of
2.0-3 MPa. When analyzing the resulting product using
gas chromatography, it was found thatabout 17.5%
cyclohexane
was
formed.
Chromatographicanalysisthe
product
of
hydrogenation of pure benzene on a nickel catalyst at
a pressure of 2.0-3.0 MPa at 250-280°C gives 25.76
mol.% of the product. The results of the analysis are
presented in the following tables (Tables 1 and 2).
The technical parameters of the products (butadiene-
1,3 and cyclohexane), synthesized by the staff of the
National University of Uzbekistan and the Central
Laboratory of the Shurtan Gas Chemical Complex,
give approximate properties to imported cyclohexane
at the JSC of the Shurtan Gas Chemical Complex. Only
for further optimization of this synthesis process, it is
necessary to continue joint research to equate its
technical parameters with imported cyclohexane.
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1.
Averko-Antonovich
L.A.
Chemistry
and
technology of synthetic rubber. - M.: Chemistry,
Kolos, 2008. - 357 p.
2.
Zhuravleva
K.A.
Obtaining
styrene
by
dehydrogenation
of
ethylbenzene
/
K.A.
Zhuravleva, A.A. Nazarov // Bulletin of the Kazan
Technological University. - 2012. - V. 15 No. 12. - p.
149-152.
3.
Kozienko A.I. Fundamentals of petrochemical
synthesis: textbook. allowance / A. I. Kozienko, T.
A., Podgorbunskaya, D. V. Gendin. - Irkutsk:
Publishing House of ISTU, 2007. - 60 p.
4.
Osipov E.V. Reconstruction of vacuum-creating
systems of the department for processing waste
products from the production of phenolacetone /
E.V. Osipov, S.I. Ponikarov, E.Sh. Telyakov, K.S.
Sadykov // Bulletin of the Kazan Technological
University. No. 18. – 2011.- p. 47-52.
5.
Timofeev V.S. Principles of technology of basic
organic and petrochemical synthesis: Textbook
for universities / V.S. Timofeev, L.A. Seraphim. -
2nd ed., revised. - M .: Higher. school, 2003. - 536
p.
6.
Khakimullin
R.R.
Obtaining
isoprene
by
dehydrogenation of isopentane and isoamylene /
R.R. Khakimullin, A.A. Nazarov, S.A. Vilokhin //
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2012. - V. 15 No. 16. - p. 154-156.
