CN110614106A

CN110614106A - Isobutane dehydrogenation catalyst with spherical double-mesoporous illite composite material as carrier, preparation method and application

Info

Publication number: CN110614106A
Application number: CN201810637924.0A
Authority: CN
Inventors: 亢宇; 刘红梅; 刘东兵
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petrochemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp; China Petrochemical Corp
Priority date: 2018-06-20
Filing date: 2018-06-20
Publication date: 2019-12-27

Abstract

The invention relates to the field of catalysts, and discloses an isobutane dehydrogenation catalyst with a spherical double-mesoporous illite composite material as a carrier, a preparation method of the isobutane dehydrogenation catalyst, the isobutane dehydrogenation catalyst prepared by the method, and application of the isobutane dehydrogenation catalyst in preparation of isobutene through isobutane dehydrogenation. The method for preparing the isobutane dehydrogenation catalyst comprises the following steps: (a) preparing a No. 1 mesoporous material filter cake with a one-dimensional hexagonal structure and a No. 2 mesoporous material filter cake with a two-dimensional hexagonal structure; (b) preparing a silica gel filter cake; (c) preparing a spherical double-mesoporous illite composite material carrier; (d) the spherical double-mesoporous illite composite material carrier is soaked in a solution containing a Pt component precursor and a Zn component precursor, and then solvent removal treatment, drying and roasting are sequentially carried out. The obtained isobutane dehydrogenation catalyst has better dehydrogenation activity and carbon deposition resistance.

Description

Isobutane dehydrogenation catalyst with spherical double-mesoporous illite composite material as carrier, preparation method and application

Technical Field

The invention relates to the field of catalysts, in particular to an isobutane dehydrogenation catalyst with a spherical double-mesoporous illite composite material as a carrier, a preparation method of the isobutane dehydrogenation catalyst, the isobutane dehydrogenation catalyst prepared by the method and application of the isobutane dehydrogenation catalyst in preparation of isobutene through isobutane dehydrogenation.

Background

Isobutene is an important organic chemical raw material and is mainly used for preparing various organic raw materials and fine chemicals such as methyl tert-butyl ether, butyl rubber, methyl ethyl ketone, polyisobutylene, methyl methacrylate, isoprene, tert-butyl phenol, tert-butyl amine, 1, 4-butanediol, ABS resin and the like. The main sources of isobutene are the by-product C4 fraction from an apparatus for producing ethylene by steam cracking of naphtha, the by-product C4 fraction from a refinery Fluid Catalytic Cracking (FCC) apparatus, and the by-product tert-butyl alcohol (TAB) in the synthesis of propylene oxide by the Halcon method.

In recent years, with the development and utilization of downstream products of isobutene, the demand of isobutene is increased year by year, and the traditional isobutene production cannot meet the huge demand of the chemical industry on isobutene, so the research and development work of a new isobutene production technology becomes a hot spot of the chemical industry. Among the most competitive technologies, isobutane dehydrogenation, n-butene skeletal isomerization and isobutene production by a novel FCC unit are known. Among the methods, the research on the reaction for preparing isobutene by directly dehydrogenating isobutane is early, and the industrial production is realized. China has abundant C4 resources, but the chemical utilization rate of C4 fraction is low in China, most of isobutane is directly used as fuel, and the waste is serious. The reasonable utilization of C4 resource is an urgent task in the petrochemical research field. Therefore, the isobutene prepared by dehydrogenating isobutane has a great development prospect in China.

The catalysts for preparing isobutene by isobutane dehydrogenation mainly comprise two types: oxide catalysts and noble metal catalysts. The oxide catalyst mainly comprises Cr₂O₃、V₂O₅、Fe₂O₃、MoO₃ZnO, etc., and a composite oxide thereof, such as V-Sb-O, V-Mo-O, Ni-V-O, V-Nb-O, Cr-Ce-O, molybdate, etc. Compared with noble metal catalysts, oxide catalysts are less expensive. However, the catalyst is easy to deposit carbon, and the catalytic activity, selectivity and stability are low. In addition, most oxide catalysts contain components with high toxicity, which is not favorable for environmental protection. The research on dehydrogenation reactions on noble metal catalysts has a long history, and noble metal catalysts have higher activity, better selectivity, and are more environmentally friendly than other metal oxide catalysts. However, the catalyst cost is high due to the expensive price of noble metals, and the performance of such catalysts has not yet reached a satisfactory level.

In order to improve the reaction performance of the catalyst for preparing isobutene by isobutane dehydrogenation, researchers have done a lot of work. Such as: the catalyst performance is improved by changing the preparation method of the catalyst (industrial catalysis, 2014, 22(2): 148-. However, the specific surface area of the currently used carrier is small, which is not beneficial to the dispersion of the active metal component on the surface of the carrier, and is also not beneficial to the diffusion of raw materials and products in the reaction process. And the pore diameter of the commonly used mesoporous material is small (the average pore diameter is 3-7nm), and if macromolecular catalytic reaction is carried out, the macromolecules are difficult to enter the pore channels, so that the catalytic effect is influenced.

Therefore, how to improve the reaction performance of the isobutane dehydrogenation catalyst is a problem to be solved in the field of preparing isobutene by isobutane dehydrogenation.

Illite is a potassium-rich silicate mica clay mineral known for its earliest discovery in illite island of the united states. The monoclinic mineral system has fine crystals and a particle diameter of 1 to 2 μm or less. Illite has an ideal chemical composition of K_0.75(Al_1.75R)[Si_3.5Al_0.5O₁₀](OH)₂The crystal mainly belongs to monoclinic system and contains water layer structure siliconAn acid salt mineral. In the formula R²⁺Represents a divalent metal cation, mainly Mg²⁺﹑Fe²⁺And the like. The chemical composition of illite clay (rock) is changed greatly due to the content of other impurities, except SiO₂、Al₂O₃In addition to the large difference in content, K₂O and Na₂O is relatively stable, typically K₂6 to 9 percent of O and 0.5 to 1.5 percent of Na 2O. The illite has the advantages of rich potassium, high aluminum, low iron, smoothness, brightness, fineness, heat resistance and other excellent chemical and physical properties, can freely release negative ions and far infrared rays, and can adsorb various harmful heavy metals and harmful gases.

In the conventional supported catalysts, a mesoporous molecular sieve material is generally used as a carrier. The mesoporous molecular sieve material has the advantages of ordered pore channels, adjustable pore diameter, larger specific surface area and pore volume and the like, so that the supported catalyst prepared by using the mesoporous molecular sieve material as a carrier has many advantages in the preparation process of organic catalytic reaction, such as high catalytic activity, less side reaction, simple post-treatment and the like, however, the large specific surface area and the high pore volume ensure that the mesoporous molecular sieve material has stronger water absorption and moisture absorption capacity, and the supported catalyst can be agglomerated in the catalytic reaction process.

Therefore, if the advantages of the mesoporous material and the illite can be combined, a novel spherical composite material is synthesized, so that the novel composite material has the advantages of both the illite and the mesoporous material. Therefore, the characteristics of the mesoporous molecular sieve material such as high specific surface area, large pore volume and large pore diameter, and a double-pore distribution structure with one-dimensional hexagonal pores and two-dimensional hexagonal pores can be retained, the advantages of high adsorption capacity due to the fact that illite has large specific surface area and a microporous structure can be combined, the uniform dispersity, catalytic activity, stability and carbon deposition resistance of the noble metal active component of the isobutane dehydrogenation catalyst can be effectively improved, the agglomeration of the mesoporous molecular sieve material can be reduced, and the flowability of the mesoporous molecular sieve material can be improved.

Disclosure of Invention

The invention aims to overcome the defect that the active group of the prior art usually takes Pt as the main metalIn terms of gamma-Al₂O₃The isobutane dehydrogenation catalyst serving as a carrier has the defects of poor active component dispersion, poor catalytic activity and stability and the like, and provides the isobutane dehydrogenation catalyst taking the spherical double-mesoporous illite composite material as the carrier, a preparation method thereof, the isobutane dehydrogenation catalyst prepared by the method and the application of the isobutane dehydrogenation catalyst in preparing isobutene through isobutane dehydrogenation.

In order to accomplish the above object, an aspect of the present invention provides a method for preparing an isobutane dehydrogenation catalyst, the method comprising the steps of:

(a) under the existence of a first template agent, trimethylpentane and ethanol, tetramethoxysilane is contacted with a first acid agent, and a product obtained after the contact is crystallized and filtered to obtain a No. 1 mesoporous material filter cake; in the presence of a second template agent, contacting tetraethoxysilane with a second acid agent, and crystallizing and filtering a mixture obtained after the contact to obtain a No. 2 mesoporous material filter cake;

(b) contacting water glass with inorganic acid, and filtering a product obtained after the contact to obtain a silica gel filter cake;

(c) mixing and ball-milling the No. 1 mesoporous material filter cake, the No. 2 mesoporous material filter cake, the silica gel filter cake and illite, pulping solid powder obtained after ball-milling with water, then performing spray drying, and removing the template agent from the obtained product to obtain a spherical double-mesoporous illite composite material carrier;

(d) and (c) dipping the spherical double-mesoporous illite composite material carrier obtained in the step (c) in a solution containing a Pt component precursor and a Zn component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting.

A second aspect of the invention provides an isobutane dehydrogenation catalyst prepared by the aforementioned process.

The third aspect of the invention provides an application of the isobutane dehydrogenation catalyst prepared by the method in preparing isobutene through isobutane dehydrogenation, wherein the method for preparing isobutene through isobutane dehydrogenation comprises the following steps: isobutane was subjected to a dehydrogenation reaction in the presence of a catalyst and hydrogen.

The carrier structure of the noble metal catalyst (including physical structures such as specific surface area, pore volume, pore size distribution and the like and chemical structures such as surface acid sites, electronic properties and the like) not only has important influence on the dispersion degree of active metal components, but also directly influences mass transfer and diffusion in the reaction process. Thus, the catalytic properties of heterogeneous catalysts, such as activity, selectivity and stability, depend both on the catalytic characteristics of the active component and on the characteristics of the catalyst support. In order to reduce the content of noble metal in the catalyst as much as possible and improve the activity and stability of the catalyst at the same time, the preparation process of the carrier is of great importance. Most commercially available activated alumina has too many surface hydroxyl groups and too strong acidity. When the aluminum oxide is used as a carrier to prepare the dehydrogenation catalyst, the surface of the catalyst is easy to deposit carbon in the reaction process, and the rapid inactivation is caused.

The inventor of the invention discovers through research that by introducing illite in the preparation process of the isobutane dehydrogenation catalyst, a supported catalyst carrier with a special pore channel structure can be obtained under a simple operation condition by using common and easily available raw materials, the carrier has the characteristics of a porous structure, a large specific surface area and a large pore volume of a mesoporous molecular sieve material, and the prepared catalyst can achieve good dehydrogenation activity, selectivity, stability and carbon deposition resistance under the condition of low noble metal loading capacity by combining the strong adsorption capacity of natural illite due to the large specific surface area and the large pore structure.

Compared with the prior art, the isobutane dehydrogenation catalyst prepared by the method provided by the invention has the following advantages:

(1) the method for preparing the isobutane dehydrogenation catalyst provided by the invention has the advantages of simple preparation process, easily controlled conditions and good product repeatability;

(2) the isobutane dehydrogenation catalyst prepared by the method provided by the invention can achieve better dehydrogenation activity, selectivity, stability and carbon deposition resistance under the condition of low loading of main active components (namely noble metals), and can effectively reduce the preparation cost of the isobutane dehydrogenation catalyst;

(3) in the isobutane dehydrogenation catalyst prepared by the method provided by the invention, the stability of a Zn center with an oxidized structure under a high-temperature reduction condition is very high, the inactivation of a single Pt component loaded on a carrier can be inhibited, carbon deposition is reduced, a strong acid center on the surface of the carrier is effectively neutralized, the surface of the carrier is free from acidity, and the dispersion degree of the Pt component is improved through a geometric effect, so that the carbon deposition risk in the reaction process of preparing isobutene by anaerobic dehydrogenation of isobutane can be remarkably reduced, the selectivity of a target product is improved, and the stability of the isobutane dehydrogenation catalyst is improved;

(4) the dispersity of the noble metal active component on the isobutane dehydrogenation catalyst prepared by the method provided by the invention is higher, so that the isobutane dehydrogenation catalyst is not easy to deactivate due to the agglomeration of active metal particles in the reaction process;

(5) the isobutane dehydrogenation catalyst prepared by the method provided by the invention shows good catalytic performance when used for preparing isobutene by anaerobic dehydrogenation of isobutane, and has the advantages of high isobutane conversion rate, high isobutene selectivity, good catalyst stability and low carbon deposition.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is an X-ray diffraction pattern of the spherical double mesoporous illite composite carrier of example 1;

FIG. 2 is an SEM scanning electron micrograph of the spherical double mesoporous illite composite support of example 1;

fig. 3 is a pore size distribution curve of the spherical double mesoporous illite composite support of example 1.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As described above, the first aspect of the present invention provides a method for producing an isobutane dehydrogenation catalyst, characterized by comprising the steps of:

In the formation process of the isobutane dehydrogenation catalyst, the No. 1 mesoporous material filter cake is a mesoporous molecular sieve material with a one-dimensional hexagonal pore channel distribution structure; the No. 2 mesoporous material filter cake is a mesoporous molecular sieve material with a two-dimensional hexagonal pore channel distribution structure.

In the process of forming the isobutane dehydrogenation catalyst, the pore size distribution is controlled to be bimodal mainly by controlling the composition of the No. 1 mesoporous material filter cake, the No. 2 mesoporous material filter cake, the silica gel filter cake and the illite, and the illite composite carrier has a bimodal distribution structure, and the microscopic morphology of the bimodal mesoporous illite composite carrier is controlled to be spherical by controlling a forming method (i.e. firstly mixing and ball-milling the No. 1 mesoporous material filter cake, the No. 2 mesoporous material filter cake, the silica gel filter cake and the illite, then pulping the obtained solid powder with water and then spray-drying), so that the spherical bimodal mesoporous illite composite carrier which has the advantages of the mesoporous molecular sieve material with the one-dimensional hexagonal pore channel distribution structure, the mesoporous molecular sieve material with the two-dimensional hexagonal pore channel distribution structure, the illite and the spherical carrier can be synthesized by using common and easily-obtained raw materials under simple operation conditions, the carrier not only has the characteristics of a porous structure, large specific surface area and large pore volume of a mesoporous molecular sieve material, but also has the characteristics of large specific surface area and special microporous structure of natural illite and strong adsorption capacity, and the isobutane dehydrogenation catalyst with no acidity on the surface, good dehydrogenation activity, high selectivity, strong stability and good carbon deposition resistance can be prepared by carrying the Pt component and the Zn component through impregnation treatment.

According to the invention, in the process of preparing the No. 1 mesoporous material filter cake and the No. 2 mesoporous material filter cake, the dosage of each substance can be selected and adjusted in a wide range. For example, in step (a), the molar ratio of the first template, ethanol, trimethylpentane and tetramethoxysilane may be 1: 100-500: 200-600: 50-200, preferably 1: 200-400: 250-400: 70-150; the molar ratio of the second template agent to the tetraethoxysilane can be 1: 1-2.5, preferably 1: 1-2.

According to the present invention, in order to make the obtained filter cake of the mesoporous material No. 1 have a one-dimensional hexagonal pore distribution structure, the kind of the first template is preferably triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene. Wherein the first template is commercially available (e.g., from Aldrich under the trade name P123, formula EO)₂₀PO₇₀EO₂₀) It can also be prepared by various conventional methods. When the first template is polyoxyethylene-polyoxypropylene-polyoxyethylene, the number of moles of the template is calculated from the average molecular weight of polyoxyethylene-polyoxypropylene-polyoxyethylene.

According to the invention, in order to make the obtained filter cake of the No. 2 mesoporous material have a two-dimensional hexagonal pore channel distribution structure, the type of the second template agent is preferably Cetyl Trimethyl Ammonium Bromide (CTAB).

According to the invention, the first acid agent may be any acid or mixture of acids present. The acid or acid mixture may be used in pure form or in the form of an aqueous solution thereof, preferably in the form of an aqueous solution. Preferably, the first acid agent is a buffered solution of acetic acid and sodium acetate; more preferably, the first acidic agent has a pH of 1-6; further preferably, the first acidic agent has a pH of 3 to 5.

According to the present invention, the second acid agent may be any of various substances or mixtures (e.g., solutions) that can be conventionally used to adjust the pH. The second acid agent is preferably used in the form of an aqueous solution. Preferably, the second acid agent is a hydrochloric acid solution, and the pH value of the second acid agent is 0-1.

According to the present invention, the condition under which the tetramethoxysilane is contacted with the first acid agent may include: the temperature is 10-60 ℃, the time is 10-72 hours, and the pH value is 1-7; preferably, the condition for contacting the tetramethoxysilane with the first acid agent may include: the temperature is 10-30 deg.C, the time is 20-40 hr, and the pH value is 3-6. In order to further facilitate uniform mixing between the respective substances, the contact of the tetramethoxysilane with the first acid agent is preferably carried out under stirring conditions. The first acid agent is preferably used in an amount such that the pH of the reaction system in which the tetramethoxysilane and the first acid agent are contacted is 1 to 7, more preferably 3 to 6.

According to the present invention, the condition for contacting the tetraethoxysilane with the second acid agent may include: the temperature is 10-60 ℃, the time is 10-72 hours, and the pH value is 0-1; preferably, the condition for contacting the tetraethoxysilane and the second acid agent can comprise: the temperature is 30-150 ℃ and the time is 10-72 hours.

In the present invention, the crystallization conditions are not particularly limited, and the crystallization conditions may include: the temperature is 30-150 ℃ and the time is 10-72 hours, and preferably, the crystallization conditions comprise: the temperature is 40-80 ℃ and the time is 20-40 hours. The crystallization is carried out by a hydrothermal crystallization method.

In the present invention, the contact manner between the first template, ethanol, the first acid agent, trimethylpentane and tetramethoxysilane is not particularly limited, and for example, the five substances may be simultaneously mixed and contacted, or several of them may be mixed and contacted first, and the remaining substances may be added to the obtained mixture and then mixed and contacted continuously. Preferably, the contacting mode is that the first template agent, the ethanol, the first acid agent and the trimethylpentane are stirred and mixed at 10-100 ℃, then the tetramethoxysilane is added and the stirring and mixing are continued.

According to the method for preparing an isobutane dehydrogenation catalyst provided by the present invention, in the step (b), the conditions for contacting the water glass with the inorganic acid may include: the temperature can be 10-60 ℃, preferably 20-40 ℃; the time may be 1 to 5 hours, preferably 1.5 to 3 hours, and the pH value is 2 to 4. In order to further facilitate uniform mixing between the substances, the contact of the water glass with the mineral acid is preferably carried out under stirring conditions.

According to the invention, the water glass is an aqueous solution of sodium silicate conventional in the art, and its concentration may be 10 to 50% by weight, preferably 12 to 30% by weight.

According to the present invention, the inorganic acid may be one or more of sulfuric acid, nitric acid and hydrochloric acid. The inorganic acid may be used in a pure form or in the form of an aqueous solution thereof. The inorganic acid is preferably used in such an amount that the reaction system has a pH of 2 to 4 under the contact conditions of the water glass and the inorganic acid.

In addition, in the above process for preparing the filter cake of the mesoporous material No. 1, the filter cake of the mesoporous material No. 2, and the filter cake of silica gel, the process for obtaining the filter cake by filtration may include: after filtration, washing with distilled water was repeated (the number of washing may be 2 to 10), followed by suction filtration. Preferably, the washing during the preparation of the filter cake of mesoporous material No. 2 is such that the pH of the filter cake is 7, and the washing during the preparation of the silica gel filter cake is such that the sodium ion content is less than 0.02 wt%.

According to the present invention, in the step (c), the amounts of the No. 1 mesoporous material filter cake, the No. 2 mesoporous material filter cake, the silica gel filter cake and the illite may be selected according to the components of the spherical double mesoporous illite composite material carrier to be obtained, and preferably, the silica gel filter cake may be used in an amount of 1 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the total amount of the No. 1 mesoporous material filter cake and the No. 2 mesoporous material filter cake; the illite can be used in an amount of 1-50 parts by weight, preferably 20-50 parts by weight; the weight ratio of the No. 1 mesoporous material filter cake to the No. 2 mesoporous material filter cake can be 1: 0.1-10, preferably 1: 0.5-2.

According to the invention, the specific operation method and conditions of the ball milling are based on that the structure of the mesoporous material is not damaged or basically not damaged and the silica gel and the illite enter the pore canal of the mesoporous material. One skilled in the art can select various suitable conditions to implement the present invention based on the above principles. Specifically, the ball milling is carried out in a ball mill, wherein the diameter of the milling balls in the ball mill can be 2-3 mm; the number of the grinding balls can be reasonably selected according to the size of the ball milling tank, and for the ball milling tank with the size of 50-150mL, 1 grinding ball can be generally used; the material of the grinding ball can be agate, polytetrafluoroethylene and the like, and agate is preferred. The ball milling conditions include: the rotation speed of the grinding ball can be 300-500r/min, the temperature in the ball milling tank can be 15-100 ℃, and the ball milling time can be 0.1-100 hours.

In the present invention, the specific operation method and conditions of the spray drying are preferably: adding a slurry prepared from the solid powder and water into an atomizer, and rotating at a high speed to realize spray drying. Wherein the spray drying conditions may include: the temperature can be 100-300 ℃, and the rotating speed can be 10000-15000 r/min; preferably, the spray drying conditions include: the temperature is 150-250 ℃, and the rotating speed is 11000-13000 r/min; most preferably, the spray drying conditions include: the temperature is 200 ℃, and the rotating speed is 12000 r/min.

According to the invention, the method for removing the template agent is preferably a calcination method. The conditions for removing the template agent may include: the temperature is 300-600 ℃, preferably 350-550 ℃, and most preferably 500 ℃; the time is 10 to 80 hours, preferably 20 to 30 hours, most preferably 24 hours.

According to the invention, in the step (d), the metal component loaded on the spherical double-mesoporous illite composite material carrier can adopt an impregnation mode, the metal component enters the pore channel of the spherical double-mesoporous illite composite material carrier by virtue of capillary pressure of the pore channel structure of the carrier, and meanwhile, the metal component can be adsorbed on the surface of the spherical double-mesoporous illite composite material carrier until the metal component is in adsorption balance on the surface of the carrier. The dipping treatment may be a co-dipping treatment or a stepwise dipping treatment. In order to save the preparation cost and simplify the experimental process, the dipping treatment is preferably co-dipping treatment; further preferably, the conditions of the co-impregnation treatment include: the spherical double-mesoporous illite composite material carrier is mixed and contacted with a solution containing a Pt component precursor and a Zn component precursor, the dipping temperature can be 25-50 ℃, and the dipping time can be 2-6 h.

According to the invention, the Pt component precursor is preferably H₂PtCl₆The Zn component precursor is preferably Zn (NO)₃)₂。

The concentration of the solution containing the Pt component precursor and the Zn component precursor is not particularly limited in the present invention, and may be conventionally selected in the art, for example, the concentration of the Pt component precursor may be 0.001 to 0.003mol/L, and the concentration of the Zn component precursor may be 0.015 to 0.1 mol/L.

According to the present invention, the solvent removal treatment can be carried out by a method conventional in the art, for example, a rotary evaporator can be used to remove the solvent in the system.

According to the present invention, in the step (d), the drying may be performed in a drying oven, and the firing may be performed in a muffle furnace. The drying conditions may include: the temperature is 110-150 ℃ and the time is 3-6 h; the conditions for the firing may include: the temperature is 600 ℃ and 650 ℃, and the time is 5-8 h.

According to the invention, in the step (d), the spherical double mesoporous illite composite material carrier, the Pt component precursor and the Zn component precursor are used in amounts such that the content of the carrier is 98-99.4 wt%, the content of the Pt component calculated by Pt element is 0.1-0.5 wt% and the content of the Zn component calculated by Zn element is 0.5-1.5 wt% in the prepared isobutane dehydrogenation catalyst based on the total weight of the isobutane dehydrogenation catalyst.

Preferably, the spherical double mesoporous illite composite material carrier, the Pt component precursor and the Zn component precursor are used in amounts such that, in the prepared isobutane dehydrogenation catalyst, based on the total weight of the isobutane dehydrogenation catalyst, the content of the carrier is 98.4-99 wt%, the content of the Pt component calculated by Pt element is 0.2-0.4 wt%, and the content of the Zn component calculated by Zn element is 0.8-1.2 wt%.

In a second aspect, the present invention provides an isobutane dehydrogenation catalyst prepared by the aforementioned process.

According to the invention, the isobutane dehydrogenation catalyst comprises a carrier, and a Pt component and a Zn component which are loaded on the carrier, wherein the carrier is a spherical double-mesoporous illite composite material carrier, the spherical double-mesoporous illite composite material carrier contains illite, a mesoporous molecular sieve material with a one-dimensional hexagonal pore channel distribution structure and a mesoporous molecular sieve material with a two-dimensional hexagonal pore channel distribution structure, the average particle size of the spherical double-mesoporous illite composite material carrier is 30-60 mu m, and the specific surface area of the spherical double-mesoporous illite composite material carrier is 150-600 m-²The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 2-8nm and 15-45nm respectively.

According to the invention, in the isobutane dehydrogenation catalyst, the spherical double-mesoporous illite composite material used as the carrier combines the advantages of a mesoporous molecular sieve material with a one-dimensional hexagonal pore distribution structure, a mesoporous molecular sieve material with a two-dimensional hexagonal pore distribution structure, illite and a spherical carrier, breaks through the limitation of a single one-dimensional pore on molecular transmission, is beneficial to good dispersion of metal components in the pore, and is suitable for being used as a carrier of a supported catalyst, the formed supported catalyst has more excellent catalytic performance in catalytic reaction, and the beneficial effects of high conversion rate of raw materials and high selectivity of products are obtained.

According to the invention, the spherical double-mesoporous illite composite material carrier has a special one-dimensional and two-dimensional hexagonal pore canal double-pore distribution structure, the average particle size of particles is measured by adopting a laser particle size distribution instrument, and the specific surface area, the pore volume and the most probable pore diameter are measured by a nitrogen adsorption method. In the present invention, the particle size refers to the particle size of the raw material particles, and is expressed by the diameter of the sphere when the raw material particles are spherical, by the side length of the cube when the raw material particles are cubic, and by the mesh size of the screen that can sieve out the raw material particles when the raw material particles are irregularly shaped.

According to the invention, the particle size of the spherical double-mesoporous illite composite material carrier is controlled within the range, so that the spherical double-mesoporous illite composite material carrier is not easy to agglomerate, and the conversion rate of reaction raw materials in the reaction process of preparing isobutene through isobutane dehydrogenation can be improved by using the supported catalyst prepared from the spherical double-mesoporous illite composite material carrier as a carrier. When the specific surface area of the spherical double mesoporous illite composite material carrier is less than 150m²When the volume/g and/or pore volume is less than 0.5mL/g, the catalytic activity of the supported catalyst prepared by using the supported catalyst is remarkably reduced; when the specific surface area of the spherical double mesoporous illite composite material carrier is more than 600m²When the volume/g and/or the pore volume is more than 1.5mL/g, the supported catalyst prepared by using the supported catalyst as the carrier is easy to agglomerate in the reaction process of preparing isobutene by isobutane dehydrogenation, so that the conversion rate of the reaction raw material in the reaction process of preparing isobutene by isobutane dehydrogenation is influenced.

Preferably, the average particle diameter of the spherical double mesoporous illite composite material carrier35-55 μm, and the specific surface area is 180-²The pore volume is 0.8-1.2mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 3-5nm and 20-30nm respectively.

According to the invention, based on the total weight of the isobutane dehydrogenation catalyst, the content of the carrier is 98-99.4 wt%, the content of the Pt component calculated by Pt element is 0.1-0.5 wt%, and the content of the Zn component calculated by Zn element is 0.5-1.5 wt%.

Preferably, the content of the carrier is 98.4-99 wt%, the content of the Pt component calculated by Pt element is 0.2-0.4 wt%, and the content of the Zn component calculated by Zn element is 0.8-1.2 wt%, based on the total weight of the isobutane dehydrogenation catalyst.

Further preferably, the average particle diameter of the isobutane dehydrogenation catalyst is 30-60 μm, and the specific surface area is 150-400m²The pore volume is 0.6-1.1mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 2-5nm and 17-30nm respectively.

According to the present invention, in the spherical double mesoporous illite composite carrier, the illite content may be 1 to 50 parts by weight, preferably 20 to 50 parts by weight, with respect to 100 parts by weight of the total amount of the mesoporous molecular sieve material having a one-dimensional hexagonal pore distribution structure and the mesoporous molecular sieve material having a two-dimensional hexagonal pore distribution structure; the weight ratio of the content of the mesoporous molecular sieve material with the one-dimensional hexagonal pore channel distribution structure to the content of the mesoporous molecular sieve material with the two-dimensional hexagonal pore channel distribution structure can be 1: 0.1 to 10, preferably 1: 0.5-2.

According to the present invention, the spherical double mesoporous illite composite material support may further contain silica introduced through silica gel. The term "silica introduced through silica gel" refers to a silica component which is brought into the finally prepared spherical double-mesoporous illite composite material carrier by using silica gel as a preparation raw material during the preparation process of the spherical double-mesoporous illite composite material carrier. In the spherical double mesoporous illite composite material carrier, the content of the silica introduced through the silica gel may be 1 to 200 parts by weight, preferably 50 to 150 parts by weight, with respect to 100 parts by weight of the total amount of the mesoporous molecular sieve material having the one-dimensional hexagonal pore distribution structure and the mesoporous molecular sieve material having the two-dimensional hexagonal pore distribution structure.

According to the present invention, the mesoporous molecular sieve material having a one-dimensional hexagonal pore distribution structure and the mesoporous molecular sieve material having a two-dimensional hexagonal pore distribution structure may each be a mesoporous molecular sieve material conventionally used in the art, and may be prepared according to a conventional method.

As described above, the third aspect of the present invention provides an isobutane dehydrogenation catalyst prepared by the foregoing preparation method and an application of the isobutane dehydrogenation catalyst in preparing isobutene through isobutane dehydrogenation, wherein the method for preparing isobutene through isobutane dehydrogenation comprises: isobutane was subjected to a dehydrogenation reaction in the presence of a catalyst and hydrogen.

When the isobutane dehydrogenation catalyst prepared by the method provided by the invention is used for catalyzing isobutane to dehydrogenate to prepare isobutene, the conversion rate of isobutane and the selectivity of isobutene can be greatly improved.

According to the present invention, in order to increase the isobutane conversion rate and prevent the catalyst from coking, it is preferable that the molar ratio of the amount of isobutane to the amount of hydrogen is 0.5 to 1.5: 1.

the conditions for the dehydrogenation reaction in the present invention are not particularly limited and may be conventionally selected in the art, and for example, the conditions for the dehydrogenation reaction may include: the reaction temperature is 550-650 ℃, the reaction pressure is 0.05-0.2MPa, the reaction time is 20-40h, and the mass space velocity of isobutane is 2-5h^-1。

The present invention will be described in detail below by way of examples.

In the following examples and comparative examples, the triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene, available from Aldrich, is abbreviated as P123 and has the formula EO₂₀PO₇₀EO₂₀The substance having a registration number of 9003-11-6 in the American chemical Abstract had an average molecular weight Mn of 5800.

The following embodimentsIn examples and comparative examples, X-ray diffraction analysis was carried out on an X-ray diffractometer, model D8Advance, available from Bruker AXS, Germany; scanning electron microscopy analysis was performed on a scanning electron microscope, model XL-30, available from FEI, USA; the nitrogen adsorption and desorption experiments of the samples are carried out on an ASAP2020M + C type full-automatic physicochemical adsorption analyzer produced by Micromeritics in America, the samples are degassed for 4 hours in vacuum at 350 ℃ before being measured, the specific surface area of the samples is calculated by adopting a BET method, and the pore volume and the average pore diameter are calculated by adopting a BJH model; the particle size distribution of the sample is carried out on a Malvern laser particle sizer; NH of sample₃TPD experiments were carried out on an AUTOCHEM2920 full-automatic chemisorption apparatus, manufactured by Micromeritics, USA: the sample was first incubated at 480 ℃ and 10% H₂Reduction in an Ar atmosphere of-90% for 1 hour. Heating to 700 ℃ in He atmosphere, standing for 1 hour, cooling to 40 ℃ to adsorb ammonia gas until saturation, purging for 1 hour in He atmosphere, heating to 700 ℃ from 40 ℃ at a speed of 10 ℃/min, and recording ammonia desorption data by using a TCD (thermal desorption detector); the rotary evaporator is produced by German IKA company, and the model is RV10 digital; the active component loading of the isobutane dehydrogenation catalyst was measured on a wavelength dispersive X-ray fluorescence spectrometer, available from parnacco, netherlands, model No. Axios-Advanced; analysis of the reaction product composition was performed on a gas chromatograph available from Agilent under model 7890A.

In the following experimental examples and experimental comparative examples, the conversion (%) of isobutane was equal to the amount of isobutane consumed by the reaction/initial amount of isobutane × 100%;

the selectivity (%) of isobutylene was defined as the amount of isobutane consumed for producing isobutylene/total consumption of isobutane × 100%.

Example 1

This example is illustrative of an isobutane dehydrogenation catalyst and a method for preparing the same.

(1) Preparation of spherical double-mesoporous illite composite material carrier

Adding 1g (0.0002mol) of triblock copolymer surfactant P123 and 1.69g (0.037mol) of ethanol into 28ml of acetic acid and sodium acetate buffer solution with the pH value of 4, stirring at 15 ℃ until the P123 is completely dissolved, then adding 6g (0.053mol) of trimethylpentane into the obtained solution, stirring at 15 ℃ for 8h, then adding 2.13g (0.014mol) of tetramethoxysilane into the solution, stirring at 15 ℃ and the pH value of 4.5 for 20h, then transferring the obtained solution into a reaction kettle with a polytetrafluoroethylene lining, crystallizing at 60 ℃ for 24h, then filtering and washing with deionized water for 4 times, and then carrying out suction filtration to obtain a No. 1 mesoporous molecular sieve material filter cake A1 with a one-dimensional hexagonal pore single-pore distribution structure;

1g (0.003mol) of cetyltrimethylammonium bromide was added to a certain amount of redistilled water, and stirred sufficiently to obtain a homogeneous solution, and the pH of the solution was adjusted to 0.2 with 10mL of a hydrochloric acid aqueous solution having a pH of 0.4. After heating the above solution to 15 ℃, ethyl orthosilicate (TEOS) was slowly added dropwise, wherein, hexadecyltrimethylammonium bromide: ethyl orthosilicate: the molar ratio of the secondary distilled water is 1: 1: 90. then stirring at 15 deg.C for 25 hr, transferring the solution into a kettle with polytetrafluoroethylene lining, and standing at 80 deg.C for hydrothermal crystallization for 40 hr. Then filtering and washing 4 times with deionized water, and then filtering to obtain a No. 2 mesoporous molecular sieve material filter cake A2 with a two-dimensional hexagonal pore path single-pore distribution structure.

Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in a weight ratio of 5:1, reacting at 30 deg.c for 2 hr, regulating the pH to 3 with 98 wt% sulfuric acid, suction filtering the obtained reaction material, and washing with distilled water to sodium ion content of 0.02 wt% to obtain silica gel filter cake B1.

And (3) putting 5g of the prepared filter cake A1, 5g of the prepared filter cake A2, 10g of the prepared filter cake B1 and 10g of illite into a 100ml ball milling tank together, wherein the ball milling tank is made of polytetrafluoroethylene, grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, and the rotating speed is 400 r/min. Sealing the ball milling tank, and carrying out ball milling for 1 hour in the ball milling tank at the temperature of 60 ℃ to obtain 30g of solid powder; dissolving the solid powder in 30g of deionized water, and spray-drying at 200 ℃ at a rotating speed of 12000 r/min; calcining the spray-dried product in a muffle furnace at 500 ℃ for 24 hours, and removing the template agent to obtain 30g of spherical double-mesoporous illite composite material carrier C1 with a one-dimensional hexagonal pore passage and a two-dimensional hexagonal pore passage double-pore distribution structure.

(2) Preparation of isobutane dehydrogenation catalyst

0.080g H₂PtCl₆·6H₂O and 0.457g Zn (NO)₃)₂·6H₂Dissolving O in 100ml of deionized water to obtain a mixture solution, soaking 10g of the spherical double-mesoporous illite composite material carrier C1 prepared in the step (1) in the mixture solution, soaking at 25 ℃ for 5h, evaporating solvent water in a system by using a rotary evaporator to obtain a solid product, and placing the solid product in a drying oven at 120 ℃ for drying for 3 h. And then roasting the mixture in a muffle furnace at the temperature of 600 ℃ for 6 hours to obtain the isobutane dehydrogenation catalyst Cat-1 (based on the total weight of the isobutane dehydrogenation catalyst Cat-1, the content of a Pt component in terms of Pt is 0.3 wt%, the content of a Zn component in terms of Zn is 1 wt%, and the balance is a carrier).

The spherical double mesoporous illite composite material carrier C1 and the isobutane dehydrogenation catalyst Cat-1 are characterized by an XRD, a scanning electron microscope and an ASAP2020-M + C type adsorption instrument.

Fig. 1 is an X-ray diffraction pattern, wherein a is an XRD pattern of the spherical double-mesoporous illite composite material carrier C1, the abscissa is 2 θ, and the ordinate is intensity, and it can be seen from a small-angle spectrum peak appearing in the XRD pattern that the XRD pattern a of the spherical double-mesoporous illite composite material carrier C1 has one-dimensional and two-dimensional hexagonal channel structures unique to mesoporous materials;

FIG. 2 is an SEM (scanning electron microscope) image, which shows that the microscopic morphology of the spherical double mesoporous illite composite material carrier C1 is mesoporous spheres with the granularity of 30-60 μm;

fig. 3 is a pore size distribution curve diagram of the spherical double mesoporous illite composite carrier C1, and it can be seen from the graph that the pore size distribution of the spherical double mesoporous illite composite carrier C1 is bimodal, and the most probable pore sizes corresponding to the bimodal are 3.5nm and 25nm, respectively.

Table 1 shows the pore structure parameters of the spherical double mesoporous illite composite material carrier C1 and the isobutane dehydrogenation catalyst Cat-1.

TABLE 1

Sample (I)	Specific surface area (m)²/g)	Pore volume (ml/g)	Most probable aperture^*(nm)	Particle size (. mu.m)
					Vector C1	300	1.5	3.5，25	30-60
Catalyst Cat-1	218	1.1	3，18	30-60

*: the first most probable aperture and the second most probable aperture are separated by a comma: the first most probable aperture and the second most probable aperture are arranged in the order from left to right.

As can be seen from the data of table 1, the specific surface area and the pore volume of the spherical double mesoporous illite composite support were reduced after the Pt component and the Zn component were loaded, which indicates that the Pt component and the Zn component entered the interior of the spherical double mesoporous illite composite support during the loading reaction.

Comparative example 1

The carrier and the isobutane dehydrogenation catalyst were prepared according to the method of example 1, except that the same weight of alumina carrier was used instead of the spherical dual mesoporous illite composite carrier C1 in the preparation of the carrier, thereby preparing the carrier D1 and the isobutane dehydrogenation catalyst Cat-D-1, respectively.

Comparative example 2

A carrier and an isobutane dehydrogenation catalyst were prepared according to the method of example 1, except that Zn (NO) was not added during the impregnation process for preparing the isobutane dehydrogenation catalyst₃)₂·6H₂O, addition of only 0.080gH₂PtCl₆·6H₂And O, only loading a single Pt component on the spherical double-mesoporous illite composite material carrier by a co-impregnation method to prepare the isobutane dehydrogenation catalyst Cat-D-2, wherein the content of the Pt component is 0.3 wt% calculated by Pt element and the balance is the carrier on the basis of the total weight of the isobutane dehydrogenation catalyst Cat-D-2).

Comparative example 3

A support and an isobutane dehydrogenation catalyst were prepared according to the method of example 1, except that there was no spray-drying step in the preparation of the isobutane dehydrogenation catalyst, and a Pt component and a Zn component were supported on the support only by the impregnation method, thereby preparing a support D3 and an isobutane dehydrogenation catalyst Cat-D-3, respectively.

Comparative example 4

A support and an isobutane dehydrogenation catalyst were prepared according to the method of example 1, except that the catalyst used was an oxide catalyst such as ZnO, thereby obtaining an isobutane dehydrogenation catalyst Cat-D-4.

Example 2

Adding 1g (0.0002mol) of triblock copolymer surfactant P123 and 1.84g (0.04mol) of ethanol into 28ml of acetic acid and sodium acetate buffer solution with the pH value of 5, stirring at 15 ℃ until the P123 is completely dissolved, then adding 9.12g (0.08mol) of trimethylpentane into the obtained solution, stirring at 15 ℃ for 8 hours, then adding 3.04g (0.02mol) of tetramethoxysilane into the solution, stirring at 25 ℃ and the pH value of 5.5 for 15 hours, then transferring the obtained solution into a reaction kettle with a polytetrafluoroethylene lining, crystallizing at 100 ℃ for 10 hours, then filtering and washing with deionized water for 4 times, and then carrying out suction filtration to obtain a No. 1 mesoporous molecular sieve material filter cake A3 with a one-dimensional hexagonal pore single-pore distribution structure;

1g (0.003mol) of cetyltrimethylammonium bromide was added to a certain amount of redistilled water, and stirred sufficiently to obtain a homogeneous solution, and the pH of the solution was adjusted to 0.1 with 7mL of a hydrochloric acid aqueous solution having a pH of 0.3. After heating the above solution to 30 ℃, ethyl orthosilicate (TEOS) was slowly added dropwise, wherein, hexadecyltrimethylammonium bromide: ethyl orthosilicate: the molar ratio of the secondary distilled water is 1: 1.5: 130. then stirring for 40h at 30 ℃, transferring the solution into a kettle with a polytetrafluoroethylene lining, and standing at 100 ℃ for hydrothermal crystallization treatment for 20 h. Then filtering and washing 4 times with deionized water, and then filtering to obtain a No. 2 mesoporous molecular sieve material filter cake A4 with a two-dimensional hexagonal pore path single-pore distribution structure.

Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in a weight ratio of 4:1, reacting at 40 deg.c for 1.5 hr, regulating the pH value to 2 with 98 wt% sulfuric acid, suction filtering the obtained reaction material, and washing with distilled water to sodium ion content of 0.02 wt% to obtain silica gel filter cake B2.

13g of the filter cake A3 prepared above, 7g of the filter cake A4, 10g of the filter cake B2 and 8g of illite are placed into a 100ml ball milling tank together, wherein the ball milling tank is made of polytetrafluoroethylene, grinding balls are made of agate, the diameter of the grinding balls is 3mm, the number of the grinding balls is 1, and the rotating speed is 300 r/min. Sealing the ball milling tank, and carrying out ball milling for 0.5 hour in the ball milling tank at the temperature of 80 ℃ to obtain 38g of solid powder; dissolving the solid powder in 12g of deionized water, and spray-drying at 250 ℃ at the rotating speed of 11000 r/min; calcining the spray-dried product in a muffle furnace at 500 ℃ for 15 hours, and removing the template agent to obtain 35g of spherical double-mesoporous illite composite material carrier C2 with a one-dimensional hexagonal pore passage and a two-dimensional hexagonal pore passage double-pore distribution structure.

(2) Preparation of isobutane dehydrogenation catalyst

0.080g H₂PtCl₆·6H₂O and 0.457g Zn (NO)₃)₂·6H₂Dissolving O in 100ml of deionized water to obtain a mixture solution, soaking 10g of the spherical double-mesoporous illite composite material carrier C2 prepared in the step (1) in the mixture solution, soaking at 25 ℃ for 5h, evaporating solvent water in a system by using a rotary evaporator to obtain a solid product, and placing the solid product in a drying oven at 120 ℃ for drying for 3 h. And then roasting the mixture in a muffle furnace at the temperature of 600 ℃ for 6 hours to obtain the isobutane dehydrogenation catalyst Cat-2 (based on the total weight of the isobutane dehydrogenation catalyst Cat-2, the content of a Pt component in terms of Pt is 0.3 wt%, the content of a Zn component in terms of Zn is 1 wt%, and the balance is a carrier).

Table 2 shows the pore structure parameters of the spherical double mesoporous illite composite material carrier C2 and the isobutane dehydrogenation catalyst Cat-2.

TABLE 2

Sample (I)	Specific surface area (m)²/g)	Pore volume (ml/g)	Most probable aperture^*(nm)	Particle size (. mu.m)
					Vector C2	360	1.3	3，27	25-45
Catalyst Cat-2	322	1.1	2，20	25-45

As can be seen from the data of table 2, the specific surface area and the pore volume of the spherical double mesoporous illite composite carrier were reduced after the Pt component and the Zn component were loaded, which indicates that the Pt component and the Zn component entered the interior of the spherical double mesoporous illite composite carrier during the loading reaction.

Example 3

Adding 1g (0.0002mol) of triblock copolymer surfactant P123 and 2.76g (0.06mol) of ethanol into 28ml of acetic acid and sodium acetate buffer solution with the pH value of 3, stirring at 15 ℃ until the P123 is completely dissolved, then adding 5.7g (0.05mol) of trimethylpentane into the obtained solution, stirring at 15 ℃ for 8h, then adding 2.13g (0.014mol) of tetramethoxysilane into the solution, stirring at 40 ℃ and the pH value of 3.5 for 10h, then transferring the obtained solution into a reaction kettle with a polytetrafluoroethylene lining, crystallizing at 40 ℃ for 40h, then filtering and washing with deionized water for 4 times, and then carrying out suction filtration to obtain a No. 1 mesoporous molecular sieve material filter cake A5 with a one-dimensional hexagonal pore single-pore distribution structure;

1g (0.003mol) of cetyltrimethylammonium bromide was added to a certain amount of redistilled water, and stirred sufficiently to obtain a homogeneous solution, and the pH of the solution was adjusted to 0.1 with 5mL of a hydrochloric acid aqueous solution having a pH of 0.5. After heating the above solution to 50 ℃, ethyl orthosilicate (TEOS) was slowly added dropwise, wherein, hexadecyltrimethylammonium bromide: ethyl orthosilicate: the molar ratio of the secondary distilled water is 1: 2: 110. then stirring at 50 deg.C for 30h, transferring the solution into a kettle with polytetrafluoroethylene lining, and standing at 140 deg.C for hydrothermal crystallization for 30 h. Then filtering and washing 4 times with deionized water, and then filtering to obtain a No. 2 mesoporous molecular sieve material filter cake A6 with a two-dimensional hexagonal pore path single-pore distribution structure.

Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in the weight ratio of 6:1, contacting and reacting at 20 deg.c for 3 hr, regulating the pH value to 4 with 98 wt% sulfuric acid, suction filtering the obtained reaction material, and washing with distilled water to sodium ion content of 0.02 wt% to obtain silica gel filter cake B3.

And (3) putting 7g of the prepared filter cake A5, 13g of the prepared filter cake A6, 30g of the prepared filter cake B3 and 12g of illite into a 100ml ball milling tank together, wherein the ball milling tank is made of polytetrafluoroethylene, grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, and the rotating speed is 550 r/min. Sealing the ball milling tank, and carrying out ball milling for 10 hours in the ball milling tank at the temperature of 40 ℃ to obtain 55g of solid powder; dissolving the solid powder in 30g of deionized water, and spray-drying at 150 ℃ at the rotating speed of 13000 r/min; calcining the spray-dried product in a muffle furnace at 450 ℃ for 70 hours, and removing the template agent to obtain 53g of spherical double-mesoporous illite composite material carrier C3 with a one-dimensional hexagonal pore passage and a two-dimensional hexagonal pore passage double-pore distribution structure.

(2) Preparation of isobutane dehydrogenation catalyst

0.080g H₂PtCl₆·6H₂O and 0.457g Zn (NO)₃)₂·6H₂Dissolving O in 100ml of deionized water to obtain a mixture solution, soaking 10g of the spherical double-mesoporous illite composite material carrier C3 prepared in the step (1) in the mixture solution, soaking at 25 ℃ for 5h, and evaporating solvent water in a system by using a rotary evaporator to obtain a solid productThe solid product was dried in a drying oven at 120 ℃ for 3 h. And then roasting the mixture for 6 hours in a muffle furnace at the temperature of 600 ℃ to obtain the isobutane dehydrogenation catalyst Cat-3 (based on the total weight of the isobutane dehydrogenation catalyst Cat-3, the content of a Pt component in terms of Pt is 0.3 wt%, the content of a Zn component in terms of Zn is 1 wt%, and the balance is a carrier).

Table 3 shows the pore structure parameters of the spherical double mesoporous illite composite material carrier C3 and the isobutane dehydrogenation catalyst Cat-3.

TABLE 3

Sample (I)	Specific surface area (m)²/g)	Pore volume (ml/g)	Most probable aperture^*(nm)	Particle size (. mu.m)
					Vector C3	350	1.1	3，20	30-50
Catalyst Cat-3	318	1	2，17	30-50

As can be seen from the data of table 3, the specific surface area and the pore volume of the spherical double mesoporous illite composite carrier were reduced after the Pt component and the Zn component were loaded, which indicates that the Pt component and the Zn component entered the interior of the spherical double mesoporous illite composite carrier during the loading reaction.

Experimental example 1

This example is intended to illustrate the preparation of isobutene using the isobutane dehydrogenation catalyst of the present invention

0.5g of isobutane dehydrogenation catalyst Cat-1 was loaded into a fixed bed quartz reactor, the reaction temperature was controlled at 590 ℃, the reaction pressure was 0.1MPa, and the isobutane: the molar ratio of hydrogen is 1: 1, the reaction time is 24 hours, and the mass space velocity of the isobutane is 4 hours^-1. By Al₂O₃The reaction product separated by the S molecular sieve column was directly fed into an Agilent 7890A gas chromatograph equipped with a hydrogen flame detector (FID) for on-line analysis, and the isobutane conversion and isobutene selectivity were obtained as shown in Table 4. After the reaction, the amount of carbon deposition in the isobutane dehydrogenation catalyst Cat-1 was measured using a TGA/DSC1 thermogravimetric analyzer from METTLER-TOLEDO, as shown in table 4.

Experimental examples 2 to 3

Isobutene was prepared by dehydrogenation of isobutane according to the method of experimental example 1, except that isobutane dehydrogenation catalyst Cat-2 and isobutane dehydrogenation catalyst Cat-3 were used instead of isobutane dehydrogenation catalyst Cat-1, respectively. The isobutane conversion, isobutene selectivity and carbon deposition amount of the isobutane dehydrogenation catalyst are shown in table 4.

Experimental comparative examples 1 to 4

Isobutene is prepared by isobutane dehydrogenation according to the method of the experimental example 1, except that isobutane dehydrogenation catalysts Cat-D-1 to Cat-D-4 are respectively adopted to replace the isobutane dehydrogenation catalyst Cat-1. The isobutane conversion, isobutene selectivity and carbon deposition amount of the isobutane dehydrogenation catalyst are shown in table 4.

TABLE 4

	Dehydrogenation catalyst	Isobutane conversion rate	Selectivity to isobutene	Carbon deposition amount of catalyst
					Experimental example 1	Cat-1	28％	85％	1.4wt％
Experimental example 2	Cat-2	27.8％	84.3％	1.2wt％
					Experimental example 3	Cat-3	27.5％	84.6％	1.6wt％
Experimental comparative example 1	Cat-D-1	11.2％	70.2％	5.3wt％
					Experimental comparative example 2	Cat-D-2	10.6％	67.5％	3.2wt％
Experimental comparative example 3	Cat-D-3	21.3％	54.3％	5.1wt％
					Experimental comparative example 4	Cat-D-4	7％	0％	5.8wt％

As can be seen from table 4, when the isobutane dehydrogenation catalyst prepared by using the spherical double mesoporous illite composite material carrier of the present invention is used in the reaction of preparing isobutene by isobutane dehydrogenation, a higher isobutane conversion rate and isobutene selectivity can be obtained after 24 hours of reaction, which indicates that the isobutane dehydrogenation catalyst of the present invention has not only a better catalytic performance, but also good stability and low carbon deposition amount.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A method for preparing an isobutane dehydrogenation catalyst, characterized in that the method comprises the following steps:

2. The method of claim 1, wherein in step (a), the molar ratio of the first template, ethanol, trimethylpentane, and tetramethoxysilane is 1: 100-500: 200-600: 50-200 parts of; the molar ratio of the second template agent to the tetraethoxysilane is 1: 1-2.5;

preferably, the first template agent is triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene, the second template agent is cetyl trimethyl ammonium bromide, the first acid agent is a buffer solution of acetic acid and sodium acetate with the pH value of 1-6, and the second acid agent is hydrochloric acid with the pH value of 0-1;

further preferably, the conditions under which the tetramethoxysilane is contacted with the first acid agent include: the temperature is 10-60 ℃, the time is 10-72 hours, and the pH value is 1-7; the condition of contacting the ethyl orthosilicate with the second acid agent comprises the following steps: the temperature is 10-60 ℃, the time is 10-72 hours, and the pH value is 0-1; the crystallization conditions include: the temperature is 30-150 ℃ and the time is 10-72 hours.

3. The method of claim 1, wherein in step (b), the conditions under which the water glass is contacted with the mineral acid comprise: the temperature is 10-60 ℃, the time is 1-5 hours, and the pH value is 2-4; the inorganic acid is one or more of sulfuric acid, nitric acid and hydrochloric acid.

4. The method according to claim 1, wherein in the step (c), the silica gel filter cake is used in an amount of 1 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the total amount of the filter cake of the No. 1 mesoporous material and the filter cake of the No. 2 mesoporous material; the weight ratio of the No. 1 mesoporous material filter cake to the No. 2 mesoporous material filter cake is 1: 0.1 to 10 portions of illite, and the dosage of the illite is 1 to 50 portions by weight.

5. The method according to claim 1, wherein in the step (d), the spherical dual mesoporous illite composite material support, the Pt component precursor and the Zn component precursor are used in amounts such that the support is contained in an amount of 98-99.4 wt%, the Pt component is contained in an amount of 0.1-0.5 wt% in terms of Pt element, and the Zn component is contained in an amount of 0.5-1.5 wt% in terms of Zn element, based on the total weight of the isobutane dehydrogenation catalyst, in the prepared isobutane dehydrogenation catalyst.

6. An isobutane dehydrogenation catalyst produced by the process of any one of claims 1-5.

7. The isobutane dehydrogenation catalyst according to claim 6, wherein the isobutane dehydrogenation catalyst comprises a carrier, and a Pt component and a Zn component supported on the carrier, wherein the carrier is a spherical double-mesoporous illite composite material carrier containing illite and having a one-dimensional hexagonal pore channel distribution structureThe mesoporous molecular sieve material and the mesoporous molecular sieve material with a two-dimensional hexagonal pore channel distribution structure are characterized in that the average particle diameter of the spherical double-mesoporous illite composite carrier is 30-60 mu m, and the specific surface area is 150-600m²The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 2-8nm and 15-45nm respectively.

8. An isobutane dehydrogenation catalyst according to claim 7, wherein the carrier is present in an amount of 98-99.4 wt%, the Pt component is present in an amount of 0.1-0.5 wt% calculated as Pt element, and the Zn component is present in an amount of 0.5-1.5 wt% calculated as Zn element, based on the total weight of the isobutane dehydrogenation catalyst;

preferably, the average particle diameter of the isobutane dehydrogenation catalyst is 30-60 mu m, and the specific surface area is 150-400m²The pore volume is 0.6-1.1mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 2-5nm and 17-30nm respectively.

9. The isobutane dehydrogenation catalyst according to claim 7, wherein the weight of the illite is 1-50 parts by weight based on 100 parts by weight of the total weight of the mesoporous molecular sieve material having a one-dimensional hexagonal pore distribution structure and the mesoporous molecular sieve material having a two-dimensional hexagonal pore distribution structure, and the weight ratio of the mesoporous molecular sieve material having a one-dimensional hexagonal pore distribution structure and the mesoporous molecular sieve material having a two-dimensional hexagonal pore distribution structure is 1: 0.1-10.

10. Use of the isobutane dehydrogenation catalyst according to any one of claims 6 to 9 for preparing isobutene by the dehydrogenation of isobutane, wherein the method for preparing isobutene by the dehydrogenation of isobutane comprises: isobutane was subjected to a dehydrogenation reaction in the presence of a catalyst and hydrogen.

11. Use according to claim 10, wherein the molar ratio of the amount of isobutane to the amount of hydrogen is between 0.5 and 1.5: 1;

preferably, the dehydrogenation reaction conditions include: the reaction temperature is 550-650 ℃, the reaction pressure is 0.05-0.2MPa, the reaction time is 20-40h, and the mass space velocity of isobutane is 2-5h^-1。