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AZERBAIJAN CHEMICAL JOURNAL No 1 2020 ISSN 2522-1841 (Online)
ISSN 0005-2531 (Print)
UDC 542.941.8/547.59
OXIDATIVE DEHYDROGENATION OF METHYLCYCLOPENTANE TO METHYLCYCLOPENTADIENE-1,3 OVER MODIFIED ZEOLITE CATALYSTS
A.M.Aliyev, M.Ya.Abbasov, U.M.Najaf-Guliyev, Z.A.Shabanova, G.A.Ali-zade,
R.Yu.Mirzoeva
M.Nagiyev Institute of Catalysis and Inorganic Chemistry, NAS of Azerbaijan
abbasov.mahir@mail.ru
Received 23.05.2019 Accepted 23.12.2019
Selective C-C- and C-H- bond activations are an important catalytic process to produce various value-added hydrocarbons oxidative dehydrogenation processes. For producing desired product with a high yield control of reaction pathway through the design of catalyst, fundamental understanding and clarification of reaction mechanism are prerequisite. In this work, we designed heterogeneous catalysts by combining {Cu2+(0.5 mas.%), Zn2+(0.2 mas.%), Co2+(0.1 mas.%), Cr3+(0.1 mas.%)} and clinoptilolite zeolites particles for oxidative dehydrogenation reaction of methylcyclopentane. Depending on the catalyst combination, the reaction pathways of dehydrogenation, ring-opening with isomerization, and ring-enlargement with hydrogenation and dehydrogenation of C5-cyclic ring to C6-cyclic ring (i.e., cyclohex-ane and benzene) can be controlled to produce various products with high yields. The conversion of methylcyclopentane was investigated over HY zeolite at 3600C. Catalytic activity of the clinoptilolite in the reaction of selective oxidative dehydrogenation of methylcyclopentane into methylcyclopentadiene has been measured experimentally. Addition of Zn increases the stability of catalytic activity and induces distinct selectivity changes. When the Zn content is increased, dehydrogenation of methylcyclopentane to methylcylopentadiene goes through a maximum and deep dehydrogenation of methylcylopen-tane to benzene remains roughly constant. This study would provide practical and fundamental insight for design of heterogeneous catalyst for controlling reaction pathways.
Keywords: methylcyclopentane, catalytic dehydrogenation, methylcyclopenten, methylcyclopentadiene, clinoptilolite.
doi.org/10.32737/0005-2531-2020-1-26-31
Introduction
The subject of present investigation was the methylcyclopentane fraction of Baku petroleum boiling between 69 and 750C, which was subjected to the action of various oxide catalysts and activated clinoptilolite zeolites. It was established that the dehydrogenation of this methylcyclopentane fraction on catalysts and atmospheric pressure led to the formation of methylcyclopentadiene, calculated on the initial methylcyclopentane fraction. This invention relates to a novel catalyst and to the use of this catalyst in the catalytic dehydrogenation of methylcyclopentane to produce methyl-1,3-cyclopentadiene. Throughout the specifications and claims of this application me-thyl-1,3-cyclopentadiene is used genetically to encompass all positional isomers as determined by the position of the methyl group on the cyclo-pentadiene ring. The invention disclosed and claimed in this application is applicable to all such isomers. Methyl-1,3-cyclopentadiene is an extremely useful compound. It has utility as a bio-
logical toxicant and in the preparation of intermediates useful in synthetic resinous compositions. To date, a commercially satisfactory process for the synthesis of methyl-1,3-cyclopentadiene has not been discovered or disclosed and this has hampered the full utilization of this material [1].
Consequently, the dehydrogenation of methylcyclopentane at high temperatures is fundamental to an overall understanding of reactions of cycloparaffins on solid acid catalysts. By using clinoptilolite most of our studies of olefins on this catalyst have been done in the temperature range 300-400°C. Natural clinop-tilolite can be used as an ion exchanger for removal of heavy metals because it has desirable characteristics of high ion exchange selectivity and resistance to different media [2].
Clinoptilolite is a natural microporous material possessing a versatile range of cation exchange properties that are exploited in many industrial processes. Clinoptilolite hails from the heulandite family of zeolites, which shares the same topology of eight- and 10-membered
ring channels running parallel to the c-axis and an intersecting eight-membered ring channel parallel to the a-axis [3]. Clinoptilolite is used in many industrial fields due primarily to its abundance and cation exchangeability. We have shown that natural clinoptilolite modified with various non-transition elements and transition cations (Zn, Cu, Co, Cr, Mn, Pd, Fe, etc.). In this work, we have used a natural clinoptilolite with rich deposits in the territory of the Republic of Azerbaijan and uptake of copper(II), co-balt(II), chrome(III), zinc(II) from their single and mixed ion solutions. The mineralogical and chemical properties of the sorption material were carried out by X-ray diffraction, X-ray fluorometry, scanning electron microscopy, and wet analysis. We have applied these cations
Cu2+, Zn 2+, Co 2+ and Cr 3+ by ion-exchange
and indicated that this one is the active catalyst for the reaction of oxidative dehydrogenation of methylcyclopentane. On the basis of experimental kinetic data by using Langmuir-Hind-shelwood rate expression we have established that reaction of oxidative dehydrogenation of methylcyclopentane proceeds with the participation of the dissociative adsorbed oxygen. The purpose of the present work is to determine a role of the components of the catalytic system, in order to simplify kinetic studies of the reaction with conjugated dehydrogenation of me-thylcyclopentane with metal-clinoptilolite. Including the effect of factors such as raw material volume rates, component ratio, temperature and quartz reactor surface conditions on the process running is obtained by us.
Experimental part
Catalysts were prepared by the ionexchange method, using of Azerbaijan natural clinoptilolite (crystallinity 84.0 % ) and the different metal cations exclusively. Catalysts were prepared by modification of zeolites with metal cations was performed by treatment their initial forms into a solution of chloride salts of the corresponding cations. Before ion exchange, the clinoptilolite has been treated with 0.5 N HCl. The number of the cations incorporated into the clinoptilolite was determined by ICP-MS Agilent 7700 and it amounted to (0.1-2)% by weight of the clinoptilo-lite. The reaction was carried out at 360-4000C and atmospheric pressure. Before the reaction, the
catalyst was activated in the air (15 mL/min) at 3 000C for 3 h. For clinoptilolite, the catalysts were typically reduced at 3 000 C for 2 h. in a flow of H2 (10 mL/min). It was noted that H2 was required in this reaction to prevent coke accumulation. At reaction temperature (typically at 3600C), saturated vapour of methylcyclopentane (Aldrich, 99.5%) at was carried by hydrogen (total flow of 15 mL/min) through a fixed bed U-shaped flow reactor made with a quartz tube (outside diameter D = 8 mm). We used the catalysts with particle size 0.25-0.63 mm. The reactor is placed in an air electric oven with automatic temperature control. Methylcyclopentane vapours and air mixed with oxygen in the mixer located in a thermostat oven, enter the reactor for the catalysis. Temperature stability is maintained in the oven with a contact thermometer. The temperature in the middle of the catalyst bed is measured with a thermocouple and recorded with the potentiometer. The reaction unit is directly connected to the analysis system through six-way valve allows the analysis of the reaction mixture without loss. The mixture exiting from the reactor gradually passes through the sample loop and is collected in the cooled trap. The analyses of the product of the reactions were also performed by gas chromatography using GC "Agilent 7890" with "Agilent 5975" MS and capillary column HP-5MS (length, 30 m) [4].
Results and discussion
The selectivity and conversion i.e., in the fraction of methylcyclopentane molecules leading to a given product, are shown explicitly in Table. A reaction temperature of 340± 200C was used for the comparison of Cu2+, Zn2+, Co2+, Cr3+ and another transition cations. From the table, we can see natural clinoptilolite, mor-denite and natural clinoptilolite with modified cations Zn2+ (exp 1, 2, 3) show lower catalytic activity in the reaction. After we add natural
3+ 9+ 0+
clinoptilolite cations;
Cr , Cu and Co is relatively higher than above mentioned ones (exp. 4, 5, 6). Combination of two cations in natural
clinoptilolite; Cu2+, Fe3+, Mn2+, Pd2+, Co2+, Zn2+ and Cr3+ increase the efficiency of methylcyc-lopentadiene from oxidative dehydrogenation of methylcyclopentane reaction (exp 7, 15). From the experimental investigation we show that the clinoptilolite with containing cations Co2+ and Cr3+ more catalytic activity than another combi-
nation of cations in the reaction (13, 14, 15). When we add fourth cation Zn2+ in this catalytic system we saw that it causes a considerable increase in the yields of methylcyclopentene and methylcyclopentadiene (exp 16, 17, 18, 19).
Deep dehydrogenation is slower while we add on Zn than on the other one metals. After we check more catalysts we arrived at a conclusion Cu2+, Cr3+, Co2+ and Zn2+ (exp 18, 19), cations with modified clinoptilolite system show more catalytic activity and relatively Fe, Mn, Pd cations shows low catalytic activity in the reaction of oxidative dehydrogenation of methylcyclopentane ( exp 7-9).
In this work we report the catalytic properties of natural clinoptilolite containing cations Cu2+ - 0.5 mas %, Zn^+ - 0.2 mas %, Co2+ - 0.1
3+
mas % and Cr - 0.1 mas % is the active catalyst for the conversion methylcyclopentane into methylcyclopenten and methylcyclopentadiene; a wide range of transition metal composition was used, including those previously investigated over different catalysts.
The activity of the zeolite catalysts in different reactions depends on; crystal structure, nature of cations, method preparation and dis-
tribution of cations of metals on a surface of the zeolite. Large, easily accessible surface deposits mainly of volcanoclastic origin, allow clinop-tilolite low-cost production by simple excavation. Clinoptilolite is one of the natural zeolites found in abundance in many locations. It is a member of the heulandite group of natural zeolites, being isostructural with the heulandite zeolite, which it differs in having higher Si/Al [5].
The unit cell of clinoptilolite is monoclinic and is usually characterized on the basis of 72 oxygen atoms (n=36) and m=24 water molecules, with Na+, K+, Ca2+, and Mg2+ as the most common charge-balancing cations. Clinoptilolite is assigned to the same framework heulandite. These units are linked together to form a two dimensional channel structure with elliptical pore openings. Channel A (10-membered ring) and B (8-membered ring) are parallel to each other and the c axis of the unit cell, while the C channel (8-membered ring) lies along a axis, intersecting both the A and B channels. Small hydrated cations (Cu2+, Zn2+, Co2+, and Cr3+) can easily enter the channels of clinoptilolite and compete for the major exchangeable cation sites, designated as M(1), M(2), M(3), and M(4) [6].
The results of the activity of modified natural clinoptilolite (CL) catalyst in the reaction of oxidative dehydrogenation of
methylcyclopentane (7=3600C F=1500 h-1, C6H12:O2:N2 = 1.74: 1:3.72)
№ exp Catalyst Conversion of C5H9CH3, X, % Selectivity, S, % Yield, A, %
C5H8 C5H6 C5H7 CH3 C5H5CH3 C6H10 C6H6 CO2
1 CL 8.9 28.1 0.5 0.8 2.6 2.5 1.3 0.7 0.5
2 Mordenit 4.2 28.6 0.1 - 1.7 1.2 0.3 - 0.9
3 CL Zn*(0,2) 17.6 21.6 0.9 0.4 3.3 3.8 3.7 4.2 1.3
4 CL Cu*(0,5) 25.3 52.2 1.8 0.8 5.3 9.4 4.1 1.9 2.0
5 CL Co*(0,1) 38.8 34.0 2.1 1.5 9.2 13.2 4.3 2.7 5.3
6 CL Cr*(0,1) 40.1 34.9 3.5 2.4 10.6 14.0 5.7 1.8 2.1
7 CL Cu Fe (0,5:0,25) 29.7 21.2 2.2 1.3 4.9 6.3 3.5 4.9 6.6
8 CL Cu Mn (0,5:0,1) 31.9 24.1 2.7 0.4 5.8 7.7 9.7 2.4 3.2
9 CL Cu Pd (0,5:0,25) 40.9 26.2 4.1 1.6 6.7 10.7 7.1 3.7 7.0
10 CL Cu Co (0.5:0,5) 32.8 20.7 2.4 0.8 7.3 6.8 4.9 3.1 5.5
11 CL Cu Cr (0.5:0,1) 26.0 27.7 3.8 2.6 4.1 7.2 6.0 2.3 2.0
12 CL Zn Cr (0.2:0,1) 39.8 27.1 5.2 3.9 4.9 10.8 7.7 4.0 3.3
13 CL Co Cr (0.1:0.1) 47.4 35.6 3.3 2.9 7.6 16.9 8.0 4.7 4.0
14 CL Co Cr (0,5:0,1) 54.7 34.4 2.7 4.2 12.4 18.8 9.3 2.2 5.1
15 CL Co Cr (0,5:0,25) 57.7 37.1 1.8 2.7 15.9 21.4 6.2 5.9 3.8
16 CL Cu Pd Zn (2:1:2) 44.1 33.3 2.9 1.6 10.8 14.7 3.2 4.5 6.4
17 CL Zn Co Cr (0.2:0.5:0.25) 45.7 49.7 3.4 2.1 4.5 22.7 2.7 2.2 8.1
18 CL Cu Zn Co Cr (2:2:1:0,5) 50.0 51.8 2.8 6.3 5.8 25.9 3.4 1.1 4.7
19 CL Cu Zn Co Cr (0.5:0.2:0.1:0.1) 75.8 55.8 1.5 4.8 17.0 42.3 4.3 2.0 3.9
* - the figures in brackets indicate the containing exchange cations in mas %.
The crystal structure shows the existence of three types of structural channels confined byten- and eight-membered tetrahedral ring systems (Figure 1).
However, no detailed single crystal structural studies for Zn ion-exchanged clinoptilolite (ZnCL) have been undertaken. The conducted by us studies revealed that CL tolerates limited to complete Zn ion-exchange. The ion-exchange and reduction processes for Co2+ reduction mechanism is complex, indirect, and sensitive to reduction temperature; consequently,
Co^ states intermediate between Co2+ and Co should be present in the reduced samples.
Fig.1 .Polyhedron model of clinoptilolite reflected of structure with exchange cations.
We know from the literature a crystal lattice of clinoptilolite consist of three open channels: A, B and C. It from the Figure 1, can be seen the polyhedron model of clinoptilolite, has a fragment of the structure with exchange cations [7].
A and B channels are parallel to axis, C and consist of tencyclic and octocyclic rings. They cross with the third octocyclic channel parallel to the a. Hexagonal planers in the structure of clinoptilolite are surrounded with channels A, B and C, in which the exchange cations are localized A planar molecule of methylcyc-lopentane is pentagonal planers surrounded exchange cations in the structure of clinoptilolite.
In clinoptilolite there are four types of places in the localization of exchange cations; they are M1 in channel A, M2 in channel B, M3 in C arranged along axis of a near center of the hexacyclic ring and M4 - place arranged in channel A in center of inversion. Their quantity is not great. M3 is arranged near M1 [8, 9].
A role of components of the catalytic system in the reaction of oxidative dehydrogena-
tion of methylcyclopentane can be explained by analysis of surrounding of the adsorbed molecules of methylcyclopentane with the exchange cations bonded with dissociative adsorbed oxygen, taking into account their bonding energies which can be found by expression [10].
q = 1 (qads + 500),
where 500 kJ/mole - energy of dissociation of molecule oxygen, qads - heat of adsorption of oxygen the pure surfaces of the polycrystal specimens of transient metals [16]; qads(Cu) = 478, qads(Zn)=240, qads(Co)=418 and qads(Cr)= 753 kJ/mole. Bonding energies of the components of catalyst with oxygen can be calculated by using formula; q0(Cu)=489 kJ/mole, q0(Zn)= 370 kJ/g-atom, q,(Co)=459 kJ/g-atom, qt(Cr)= 612 kJ/g-atom.
Contingent on the solidity of these bonds propellant force of hydrogen atoms of methyl-cyclopentane changes. The maximum propel-lant force of hydrogen atoms of methylcyclo-pentane is indicated by the oxygen atoms bonded with the component of the catalyst. From experimental data presented in Table and with taking regard to the bonding energies of the components of the catalyst with oxygen atom it is possible to group the active centers of components of the catalyst for reaction of oxidative dehydrogenation of methylcyclopentane which are responsible for formation of methylcyclo-pentadiene and methylcyclopentene. Total scheme of oxidative dehydrogenation of me-thylcyclopentane on these active centers is presented in Figure 2.
Fig. 2. Schematic representation of the reaction of oxidative dehydrogenation on an active center of modified clinoptilolite catalyst,CL-CuCrCoZn, i - exchange cation,
i=1-4; 1 - Cr3+, 2 - Cu2+, 3 - Zn2+, 4 - Co2+.
There are three types of active centers for reaction of oxidative dehydrogenation of
0
methylcyclopentane into methylcyclopentadi-ene;{Mi(1),M2(2)}and{Mi(1),M2(4)}, {Mi(2), M2(4)}. Because of solidity of bonds of cations; Cr3+,Cu2+and Co2+with oxygen atoms they have very strongly driving force of hydrogen atoms of methylcyclopentane, By adding Zn simultaneously increase forming molecules of methyl-cyclopentene with stabilized Zn=0 which has relatively lower bonding energy (Figure 3).
СЩ
Fig. 3. Schematic representation of formation of methylcyclopentadiene on an active center {M1(1), M2(4),}of modified clinoptilolite catalyst CL-CuCrCoZn.
By means of analysis of the experimental data and bonding energies of the components of the catalyst with oxygen atoms three types of active centers may be suggested for reaction oxi-dative dehydrogenation methylcyclopentane into methylcyclopentene; {Mi(1), M2(3)}, {Mi(2), M2(3)},{Mi(4), M2(3)}.
AM
HO 70
60 J __
4'J
30
012345678
T,s
Fig 4. Dependence of oxidative dehydrogenation of methylcyclopentane on the average residence time, т; i -conversion of methylcyclopentane, X %; 2 - yield of methylcyclopentadiene, A4,%; 3 - yield of methylcyclo-pentene, A3,%; 4 - yield of benzene, A6,%; T=3600C, C6Hi2:O2:N2=i.74:i:3.72 .
Conclusion
It should be noted that an advantage formation of methylcyclopentadiene depends on
amount of active centers for corresponding reaction which depends on concentration and sequence of incorporating of cations by ionexchange. With the purpose of obtaining of methylcyclopentadiene the optimum succession incorporating of cation in clinoptilolite is Cu2+(0.5 mas%), Zn2+ (0.2 mas %), Co2+(0.2 mas %), Cr3+(0.2 mas %).
The source of the methylcyclopentane oxidative decomposition reaction products depends on the amounts and the concentration of effective centers for the reaction and the combination of ion exchange cations. Obtaining of methylcyclopentadien the optimum succession incorporating of cation in clinoptilolite is Cu2+ (0.5 mas%) ^ Zn2+ ( 0.2 mas % ) ^ Co2+(0.2 mas %) ^ Cr3+ (0.2 mas %) ^ CL. From experimental data were confirmed that the kinetic scheme of the considered reactions over the active catalytic system does not proceed on a consecutive mechanism. From these experimental data, it can be accomplished that on the surface of the catalyst there different active centers obtaining which are responsible for the formation of the products of the reaction.
References
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3. Matthew Johnson., David O'Connor, Paul Barnes C., Richard A. Catlow, Scott L. Owens, Gopina-than Sankar, Robert Bell.,Simon J. Teat, Richard Stephenson. Cation Exchange, Dehydration, and Calcination in Clinoptilolite: In Situ X-ray Diffraction and Computer Modeling. J. Phys. Chem. B. 2003. i07. P. 942-95i.
4. Aliyev A.M., Abbasov M.Y., Shabanova Z.A., Ali-zadeh G.A., Bahmanov M.F., Najaf-Guliyev U.M., Huseynova T.I. A study of the kinetics and mechanism of the selective oxidative dehydro-genation reaction of cyclopentane to cyclopentadi-ene-i,3 over modified zeolite catalysts. Azerb. Chem. Journ. 20i8. No 3. P. ii-20.
5. Hernandez M.A., Nitrogen-Sorption Characterization of the Microporous Structure of Clinoptilo-
lite-Type Zeolites. J. Porous Materials. 2000. No 7. P. 443-454.
6. Iznaga I.R., Gomez A., Fuentes G.R., Aguilar A. B., Ballan, J.S., Natural clinoptilolite as an exchanger of Ni2+ and NH++ ions under hydrothermal conditions and high ammonia concentration. Microporous and Mesoporous Materials. 2002. No 53. P. 71-80.
7. Koyama K., Takeushi Y. Clinoptilolite: the distribution of Potassium atoms and its role in thermal stability. Z.Kristallogr. 1977. V. 145. P. 216-239.
8. Boreskov G.K. Geterogennyi kataliz. M.: Nauka. 1986. 300 s.
9. Toyoshima I., SamorjaiG.A.Heats of chemisorp-tions of O2, H2, CO, CO2 and N2 on polycrystalline and single crystal transition metal. Catal. Rev. 1979. V. 19. No 1. P. 105-159.
10. Armbruster Th. Dehydration mechanism of clinoptilolite and heulandite; single-crystal X-ray study of Na-poor, Ca-, K-, Mg-rich clinoptilolite at 100 K. Am. Maner. 1993. V.78. P. 260-264.
METILTSIKLOPENTANIN METILTSIKLOPENTADIEN 1.3-Э MODIFIKASIYA OLUNMU§ SEOLIT KATALÍZATORLARI ÜZORÍNDO OKSÍDLO§DÍRÍCÍ DEHÍDROGENLO§MOSÍ
A.M.0liyev, M.Y.Abbasov, U.M.Nacaf-Quliyev, Z.A.§abanova, G.O.Oli-zada, RY.Mirzayeva
Selektiv C-C va C-H alaqalarinin aktivla§masi ,müxtalif qiymatli karbohidrogen alavalarinin oksidla¡jdirici dehidrogen-la§masi proseslarinin alinmasi ügün vacib bir katalitik prosesdir. istadiyiniz mahsulu yüksak mahsuldarliqla alda etmak ügün, katalizatorun dizayn edilmasi ila reaksiya yolunun idara olunmasi va reaksiya mexanizminin asasli anla§ilmasi va aydinlaíjdmlmasi vacib §artdir. Bu i§da metiltsiklopentanin oksidla¡jdirici dehidrogenla§ma reaksiyasi ügün {Cu2+ (0.5 mas.%), Zn2+ (0.2 mas.%), Co2+ (0.1 mas.%), Cr3+(0.1 mas.%)} hissaciklari va (CL) klinoptilolit zeolitlari birla§diraiak heterogen katalizatorlan hazirladiq. Katalizatorun kombinasiyalarindan asili olaraq, dehidrogenla§ma reaksiyasinin yollarina, izomerla§ma ila halqanin agilmasina, hidrogenla§ma va dehidrogenla§ma ila C5 tsiklik halqanin C6 tsiklik halqaya (tsikloheksan va benzol ) böyümasi kimi müxtalif mahsullann yüksak giximla alinmasina nazarat etmak olar. Metiltsiklopentanin konversiyasi 3600C-da HY zeolitinda ara§dirildi. Metiltsiklopentanin metiltsiklopentadina selektiv oksidla§diriri dehidrogenla§ma reaksiyasinda klinikoptilolitin katalitik faaliyyati eksperimental olaraq ölgülmüijdür. Zn alava edilmasi katalitik faaliyyatin sabitliyini artinr va selektivliyin farqli dayi§ilmasina sabab olur. Zn miqdarini artdiqda metiltsiklopentanin metilsilopentadiena dehidrogenla§masi maksimum daracaya gatir va metilsilopentanin benzola qadar darin dehidrogenla§masi taxminan sabit qalir. Bu tadqiqat reaksiya yollarini idara etmak ügün heterogen katalizatorun yaradilmasi ügün praktik va asasli fikirlar taqdim edacakdir.
Agar sözlar: Metilstiklopentan, katalitik dehidrogenh§m3, metiltsiklopenten, etiltsiklopentadien, klinoptilolit.
ОКИСЛИТЕЛЬНОЕ ДЕГИДРИРОВАНИЕ МЕТИЦИКЛОПЕНТАНА В МЕТИЦИКЛОПЕНТАДИЕН-1,3 НА МОДИФИЦИРОВАННЫХ ЦЕОЛИТНЫХ КАТАЛИЗАТОРАХ
А.М.Алиев, М.Я.Аббасов, У.М.Наджаф-Кулиев, З.А.Шабанова, Г.А.Али-заде, Р.Ю.Мирзоева
Селективная активация С—С- и С-Н-связей является важной стадией каталитических процессов окислительного дегидрирования углеводородов с целью получения ценных продуктов. Для получения целевого продукта с высоким выходом управление направлением реакции путем конструирования катализатора фундаментальные знания и представления о механизмах реакции являются необходимыми положениями. В настоящей работе нами представлены результаты исследований по конструированию гетерогенных катализаторов путем сочетания {Cu2+(0.5 масс.%), Zn2+(0.2 масс.%), Co2+(0.1 масс.%), Cr3+(0.1 масс.%)} катионов и клиноптилолитных цеолитов для реакции окислительного дегидрирования метилциклопентана. В зависимости от присоединения катализаторов пути реакций дегидрирования, изомеризация с открытием циклов и гидрирования с расширением циклов и дегидрирования ^-циклического кольца в ^-циклического кольца (т.е. циклогексан и бензол) могут контролироваться для получения различных продуктов с высокими выходами. Конверсия метилцикло-пентана исследована на HY цеолите при 3600C. Каталитическая активность клиноптилолита в реакции селективного окислительного дегидрирования метилциклопентана в метилциклопентадиен была измерена экспериментально. Добавление Zn повышает стабильность каталитической активности и вызывает различные изменения селективности. При увеличении содержания Zn дегидрирование метилциклопентана в метилциклопентадиен проходит через максимальное и глубокое дегидрирование метилциклопентана в бензол и остается приблизительно постоянным. Это исследование дает практические и фундаментальные знания для разработки гетерогенного катализатора для регулирования путей реакции.
Ключевые слова: метилциклопентан, каталитическое дегидрирование, метилциклопентен, метилциклопентадиен, клиноптилолит.
