Hierarchical pore molecular sieve, preparation method thereof and application of hierarchical pore molecular sieve in cycloalkane dehydrogenation

Abstract

The invention discloses a hierarchical pore molecular sieve, a preparation method thereof and application of the hierarchical pore molecular sieve in cycloalkane dehydrogenation. The silica-alumina ratio of the hierarchical pore molecular sieve is 20-1000. The micropore specific surface area of the hierarchical pore molecular sieve is 100-300m < 2 > / g, and the micropore volume is 0.03-0.20 cm < 3 > / g; the mesoporous specific surface area of the hierarchical porous molecular sieve is 150-500m < 2 > / g, and the mesoporous volume is 0.20-0.60 cm < 3 > / g. The preparation method of the catalyst has the characteristics of stability, controllability and good repeatability. The steps and production equipment of the method are simple, the used raw materials and reagents are common and low in price, and large-scale industrial application is facilitated. In addition, the method has high conversion rate during conversion of methylcyclohexane, and the selectivity of the product toluene is high.

Description

Technical Field

[0001] The present application relates to a hierarchical pore molecular sieve, a preparation method thereof, and an application thereof in naphthene dehydrogenation, belonging to the field of catalyst materials. Background Art

[0002] Except for nuclear fuel, the calorific value of hydrogen ranks first among all fossil fuels, chemical fuels, and biofuels, reaching as high as 1.42×10 5 kJ / kg, which is three times the calorific value of gasoline. Therefore, hydrogen is widely regarded as an ideal clean energy source. However, the main challenges in the current domestic development lie in the storage and transportation of hydrogen energy, which has become a bottleneck for its wide application. Compared with traditional hydrogen storage methods, the organic liquid hydrogen storage technology has obvious advantages in terms of safety, convenience, and environmental protection, especially in long-distance transportation, seasonal storage, and cross-regional transportation. Therefore, the development of efficient, safe, and convenient hydrogen storage technologies, especially organic liquid hydride hydrogen storage systems, will be the key factor for the ultimate realization of the "hydrogen economy".

[0003] The main naphthene hydrogen storage liquids include methylcyclohexane, perhydrodibenzyltoluene, cyclohexane, dicyclohexane, and decalin. Among them, cyclohexane has a relatively high hydrogen storage density (7.2 wt%), but its dehydrogenation product benzene is carcinogenic, so its application is limited. Decalin and dicyclohexane have higher hydrogen storage densities (7.3 wt%), but their dehydrogenation products (naphthalene and biphenyl) are solid at normal temperature and pressure, which is not conducive to operation. Generally speaking, among naphthene-based hydrogen storage liquids, the liquid hydrogen storage system composed of methylcyclohexane and toluene not only has a relatively high hydrogen storage density, but also is cheap and easily available. In addition, they have the advantages of short carbon chains, high thermal stability, and no large amount of side reactions of carbon chain breakage during cycling, and are very suitable for use as liquid materials for large-scale hydrogen storage.

[0004] Pt-based catalysts are widely used in various alkane dehydrogenation reactions because they can efficiently and selectively activate C-H bonds. Research shows that Pt particles usually have a diameter between 1.4 and 2.0 nm, which causes them to be unable to enter the pores of microporous molecular sieves and can only be evenly distributed on the outer surface of the crystal. In addition, the pore diameter of microporous molecular sieves is relatively small, close to or smaller than the molecular sizes of reactants and products, so reactant molecules cannot contact the active sites inside the pore channels of the molecular sieve. Moreover, the diffusion of molecules in the pore channels is slow and prone to carbon deposition, which has an adverse impact on the activity, service life, and product selectivity of the catalyst. Recent research has pointed out that introducing mesoporous structures into microporous zeolite crystals can significantly improve the mass transfer efficiency of zeolite materials and their catalytic activity towards hydrocarbon molecules. CN114426294A discloses a ZSM-5 / MCM-41 zeolite molecular sieve, which has both a layered structure and a hierarchical pore structure. The interlayer thickness of the layered structure is 5 nm to 10 nm, and the hierarchical pore structure includes mesopores with a pore diameter of 5 nm to 10 nm and micropores with a pore diameter of 0.1 nm to 1 nm. CN108568310A discloses a micro-mesoporous ZSM-5 / MCM-41 composite molecular sieve methanation catalyst. Although the alkali solution post-treatment method is simple to operate and low in cost, it also faces challenges such as reducing the crystallinity of zeolites, balancing the pore structure and acid properties, and regulating the mesopore size distribution. Summary of the Invention

[0005] To solve these problems, a hierarchical pore molecular sieve with a composite double-crystal structure can be prepared through an alkali treatment desilication step followed by crystallization synthesis in a hydrothermal reaction kettle. The synthesis of the Z / MCM-41 composite molecular sieve (where Z represents a molecular sieve with good hydrothermal stability, such as ZSM-5, MOR, Beta, or Y, etc.) not only enhances the hydrothermal stability of the MCM-41 molecular sieve but also can adjust its acidity and ion exchange characteristics. Mesoporous materials with an ordered pore structure and a high specific surface area exhibit excellent performance in the adsorption and diffusion of macromolecules. By combining the hydrothermal stability and strong acidity of microporous materials with the high specific surface area and large pore diameter of mesoporous materials, a hierarchical pore ZSM-5 / MCM-41 molecular sieve composite material is developed, and materials with this structure will demonstrate excellent performance in the dehydrogenation of naphthenes.

[0006] In one aspect of the present application, a hierarchical pore molecular sieve is provided, and the silica-alumina ratio of the hierarchical pore molecular sieve is 20 to 1000;

[0007] The hierarchical pore molecular sieve has micropores and mesopores;

[0008] The micropore specific surface area of the hierarchical pore molecular sieve is 100 to 300 m 2 / g, and the micropore volume is 0.03 to 0.20 cm 3 / g;

[0009] The mesoporous specific surface area of the hierarchical zeolite is 150 - 500 m 2 / g, and the mesoporous volume is 0.20 - 0.60 cm 3 / g.

[0010] Optionally, the silica-alumina ratio of the hierarchical zeolite is independently selected from any value among 20, 50, 80, 100, 200, 400, 600, 800, 1000 or the range value between any two of the above.

[0011] Optionally, the mesoporous pore diameter of the hierarchical zeolite is 3 - 12 nm.

[0012] In another aspect of the present application, a preparation method of the above-mentioned hierarchical zeolite is provided, and the preparation method includes:

[0013] (1) After subjecting the zeolite to alkali treatment in an alkali solution, adding it to a solution containing a surfactant for hydrothermal reaction, centrifuging I, drying I, and calcining I to obtain an intermediate;

[0014] (2) Performing ammonium exchange on the intermediate obtained in step (1), and centrifuging II, drying II, and calcining II to obtain the hierarchical zeolite.

[0015] As a specific embodiment, the preparation method of the hierarchical zeolite includes:

[0016] (1) Desiliconizing the untreated zeolite in a high-concentration alkali solution, then transferring the zeolite into a hydrothermal reaction kettle, adding a surfactant solution for crystallization, and then centrifuging I, filtering, drying I, and high-temperature calcining I; (2) Performing ammonium exchange on the sample obtained in step (1), and then obtaining the hierarchical zeolite through centrifuging II, filtering, drying II, and high-temperature calcining II.

[0017] Optionally, the zeolite is selected from any one of ZSM-5 zeolite, Beta zeolite, and ZSM-11 zeolite.

[0018] Preferably, the zeolite is ZSM-5 zeolite.

[0019] Optionally, in step (1), the alkaline substance in the alkali solution is selected from at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate.

[0020] Optionally, the alkali solution is a sodium hydroxide solution.

[0021] Optionally, in the alkali solution, the concentration of the alkaline substance is 0.1 - 3 mol / L;

[0022] The solid-liquid ratio of the zeolite to the alkali solution is 1:10 - 50 g / ml.

[0023] Optionally, the concentration of the basic substance is independently selected from any value among 0.1 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L or the range value between any two of the above.

[0024] Optionally, the solid-liquid ratio of the molecular sieve to the alkali solution is independently selected from any value among 1:10 g / ml, 1:20 g / ml, 1:30 g / ml, 1:40 g / ml, 1:50 g / ml or the range value between any two of the above.

[0025] Optionally, the surfactant is selected from at least one of dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide.

[0026] Preferably, the surfactant is hexadecyl trimethyl ammonium bromide.

[0027] Optionally, in the solution containing the surfactant, the concentration of the surfactant is 0.05 - 0.3 mol / L.

[0028] Optionally, the concentration of the surfactant is independently selected from any value among 0.05 mol / L, 0.10 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L or any range value between any two of the above.

[0029] Optionally, in step (1), the temperature of the alkali treatment for desilication is 30 - 90 °C;

[0030] The time of the alkali treatment for desilication is 10 - 60 minutes.

[0031] Optionally, the temperature of the alkali treatment for desilication is independently selected from any value among 30 °C, 40 °C, 50 °C, 60 °C, 65 °C, 70 °C, 80 °C, 90 °C or the range value between any two of the above.

[0032] Optionally, the time of the alkali treatment for desilication is independently selected from any value among 10 minutes, 20 minutes, 25 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes or the range value between any two of the above.

[0033] Optionally, the temperature of the hydrothermal reaction is 60 - 120 °C;

[0034] The time of the hydrothermal reaction is 12 - 36 hours.

[0035] Optionally, the temperature of the hydrothermal reaction is independently selected from any value of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C or a range value between any two of the above.

[0036] Optionally, the time of the hydrothermal reaction is independently selected from any value of 12 hours, 18 hours, 24 hours, 30 hours, 36 hours or a range value between any two of the above.

[0037] Optionally, the rotation speed of the first centrifugation is 4000 rpm;

[0038] The time of the first centrifugation is 5 minutes.

[0039] Optionally, the temperature of the first drying is 60 - 120°C;

[0040] The time of the first drying is 10 - 24 hours.

[0041] Optionally, the temperature of the first drying is independently selected from any value of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C or a range value between any two of the above.

[0042] Optionally, the time of the first drying is independently selected from any value of 10 hours, 12 hours, 16 hours, 20 hours, 24 hours or a range value between any two of the above.

[0043] Optionally, the temperature of the first calcination is 500 - 700°C;

[0044] The time of the first calcination is 2 - 8 hours.

[0045] Optionally, the temperature of the first calcination is independently selected from any value of 500°C, 550°C, 600°C, 650°C, 700°C or a range value between any two of the above.

[0046] Optionally, the time of the first calcination is independently selected from any value of 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours or a range value between any two of the above.

[0047] Optionally, in step (2), the ammonium salt solution used for ammonium exchange is ammonium nitrate solution;

[0048] In the ammonium nitrate solution, the concentration of ammonium nitrate is 0.2 - 1 mol / L.

[0049] Optionally, the solid-liquid ratio of the intermediate to the ammonium nitrate solution is 1:10 - 30 g / ml.

[0050] Optionally, the concentration of the ammonium nitrate is independently selected from any value of 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L or the range value between any two of the above.

[0051] Optionally, the temperature of the ammonium exchange is 70-90 °C;

[0052] The time of the ammonium exchange is 1-3 hours;

[0053] The number of repeated exchanges of the ammonium exchange is 2-6 times.

[0054] Optionally, the temperature of the ammonium exchange is independently selected from any value of 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 85 °C, 90 °C or the range value between any two of the above.

[0055] Optionally, the time of the ammonium exchange is independently selected from any value of 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or the range value between any two of the above.

[0056] Optionally, the number of repeated exchanges of the ammonium exchange is independently selected from any value of 2 times, 3 times, 4 times, 5 times, 6 times or the range value between any two of the above.

[0057] Optionally, the rotation speed of the second centrifugation is 4000 revolutions;

[0058] The time of the second centrifugation is 5 minutes.

[0059] Optionally, the temperature of the second drying is 100-120 °C;

[0060] The time of the second drying is 10-24 hours.

[0061] Optionally, the temperature of the second drying is independently selected from any value of 100 °C, 110 °C, 120 °C or the range value between any two of the above.

[0062] Optionally, the time of the second drying is independently selected from any value of 10 hours, 12 hours, 16 hours, 20 hours, 24 hours or the range value between any two of the above.

[0063] Optionally, the temperature of the second calcination is 400-600 °C;

[0064] The time of the second calcination is 2-5 hours.

[0065] Optionally, the temperature of the second calcination is independently selected from any value of 400 °C, 450 °C, 500 °C, 550 °C, 600 °C or the range value between any two of the above.

[0066] Optionally, the time of the second calcination is independently selected from any value of 2 hours, 3 hours, 4 hours, 5 hours or a range value between any two of the above.

[0067] In another aspect of the present application, a cycloalkane dehydrogenation catalyst is provided, and the cycloalkane dehydrogenation catalyst comprises a carrier and an active component;

[0068] The carrier is selected from the above-mentioned hierarchical pore molecular sieves;

[0069] The active component comprises an active element, and the active element is selected from at least one of Pt, Pd, and Rh;

[0070] The active component accounts for 0.01 to 10 wt% of the mass of the hierarchical pore molecular sieve.

[0071] Optionally, the active component accounts for the mass of the hierarchical pore molecular sieve carrier and is independently selected from any value of 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.1 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt% or a range value between any two of the above.

[0072] In another aspect of the present application, a preparation method of the above-mentioned cycloalkane dehydrogenation catalyst is provided, and the preparation method comprises:

[0073] An aqueous solution containing a precursor of the active component is impregnated onto the hierarchical pore molecular sieve in an excessive amount, stirred, dried for the third time, and calcined for the third time to obtain the cycloalkane dehydrogenation catalyst.

[0074] Optionally, the precursor of the active component is selected from at least one of H2PtCl6, PdCl2, and RhCl3.

[0075] Optionally, the precursor of the active component is H2PtCl6·6H2O.

[0076] Optionally, the mass ratio of the hierarchical pore molecular sieve to the volume of the aqueous solution containing the precursor of the active component is 1:5 to 10 ml / g.

[0077] Optionally, the excessive impregnation time is 12 to 24 hours.

[0078] Optionally, the excessive impregnation time is independently selected from any value of 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours or a range value between any two of the above.

[0079] Optionally, the temperature of the third drying is 60 to 120 °C;

[0080] The time of the third drying is 10 to 24 hours.

[0081] Optionally, the temperature of the third drying step is independently selected from any value of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C or a range value between any two of the above.

[0082] Optionally, the time of the third drying step is independently selected from any value of 10 hours, 12 hours, 16 hours, 20 hours, 24 hours or a range value between any two of the above.

[0083] Optionally, the temperature of the third calcination step is 500 - 700°C;

[0084] The time of the third calcination step is 2 - 8 hours.

[0085] Optionally, the temperature of the third calcination step is independently selected from any value of 500°C, 550°C, 600°C, 650°C, 700°C or a range value between any two of the above.

[0086] Optionally, the time of the third calcination step is independently selected from any value of 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours or a range value between any two of the above.

[0087] In another aspect of the present application, a method for dehydrogenating cycloalkanes is provided, in which a raw material containing cycloalkanes is contacted with a pre-reduced catalyst in a fixed-bed reaction tube, and reacted to obtain hydrogen and a dehydrogenated product;

[0088] The catalyst is the above-mentioned cycloalkane dehydrogenation catalyst.

[0089] Optionally, the time of the pre-reduction is 1 - 3 hours, the temperature of the pre-reduction is 200 - 500°C, and the pre-reduction is carried out in an H2 atmosphere.

[0090] Optionally, the time of the catalyst pre-reduction is independently selected from any value of 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or a range value between any two of the above.

[0091] Optionally, the temperature of the catalyst pre-reduction is independently selected from any value of 200°C, 300°C, 400°C, 500°C or a range value between any two of the above.

[0092] Optionally, the reaction is carried out in an inert atmosphere;

[0093] The inert atmosphere is selected from at least one of N2 and Ar.

[0094] Preferably, the inert atmosphere is Ar.

[0095] Optionally, the weight hourly space velocity of the naphthene-containing feedstock is 2 to 12 h -1 ;

[0096] The pressure of the reaction is 0.1 MPa;

[0097] The temperature of the reaction is 200 to 700 °C.

[0098] Optionally, the weight hourly space velocity is independently selected from any value of 2 h -1 , 4 h -1 , 6 h -1 , 8 h -1 , 10 h -1 , 12 h -1 or a range value between any two of the above.

[0099] Optionally, the reaction temperature is independently selected from any value of 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C or a range value between any two of the above.

[0100] The conversion rate of the naphthene prepared by the method is greater than 90%, and the selectivity is greater than 85%.

[0101] The beneficial effects that can be produced by this application include:

[0102] (1) Improving catalytic efficiency and selectivity: The hierarchical pore composite molecular sieve catalyst enhances the availability of active sites and improves the efficiency of the naphthene dehydrogenation reaction. At the same time, this structure optimizes the diffusion of reactants and products, effectively improving the selectivity of the target product and reducing side reaction products.

[0103] (2) Improving thermal stability and durability: The hierarchical pore composite molecular sieve catalyst shows better thermal stability and durability, enabling it to operate stably at higher temperatures and extending its service life. This is particularly important for industrial applications because high thermal stability and durability mean longer operating cycles and lower maintenance costs.

[0104] (3) Reducing energy consumption and environmental impact: The hierarchical pore composite molecular sieve catalyst can achieve efficient dehydrogenation reactions at lower temperatures and pressures, thereby reducing energy consumption and production costs. At the same time, the improved reaction selectivity also means reducing the generation of waste and harmful by-products, which is of positive significance for environmental protection.

[0105] (4) The method has the characteristics of stability, controllability and good repeatability. The steps and production equipment of this method are simple, and the raw materials and reagents used are common and inexpensive, which is conducive to large-scale industrial applications. In addition, this method has a high conversion rate when converting methylcyclohexane and a high selectivity for the product toluene. Description of the Drawings

[0106] Figure 1 This is the catalyst 3 in Example 3 of the present invention # Nitrogen physical adsorption-desorption curve (a) and pore size distribution curve (b) of Detailed implementation mode

[0107] As described above, the present invention relates to a method for preparing a hierarchical pore molecular sieve catalytic material, first performing desilication by alkali treatment, and then transferring it to a hydrothermal reaction kettle for recrystallization to produce a composite molecular sieve structure. In addition, the present invention also relates to a method for using the catalyst in the dehydrogenation reaction of cycloalkanes. The catalytic material improves the conversion rate and product selectivity in the dehydrogenation reaction of cycloalkanes

[0108] The following describes the present application in detail with reference to examples, but the present application is not limited to these examples

[0109] Unless otherwise specified, the raw materials and reagents in the examples of the present application are purchased through commercial channels

[0110] The analysis methods in the examples of the present application are as follows

[0111] Characterization of specific surface area and pore size distribution

[0112] A Micromeritics ASAP 2460 physical adsorption instrument is used for specific surface area and pore size distribution characterization

[0113] The analysis conditions for specific surface area and pore volume are as follows: 0.1 g of the catalyst is loaded into a quartz adsorption tube, vacuum-treated at 350 °C for 12 h to remove the moisture and impurities adsorbed by the molecular sieve, and a nitrogen adsorption / desorption experiment is carried out at a temperature of 77.4 K. The Brunauer-Emmett-Teller (BET) equation is used to calculate the micropore specific surface area of the sample, and the t-plot method is used to calculate the micropore specific surface area, micropore volume, mesopore specific surface area, and mesopore volume of the molecular sieve sample. The BJH method is used to obtain the pore size distribution of the sample

[0114] Characterization by gas chromatography

[0115] Product analysis is carried out using an Agilent gas chromatograph 7890B for on-line analysis. The FID detector analyzes organic substances (chromatographic column: PEG-20M), and the TCD detector analyzes N2 and H2 (chromatographic column: TDX-01)

[0116] In the examples of the present application, the prepared catalyst is subjected to a methylcyclohexane dehydrogenation test, and the conversion rate of methylcyclohexane and the selectivity of toluene are defined as follows

[0117] Methylcyclohexane conversion rate

[0118]

[0119] Toluene selectivity:

[0120]

[0121] Preparation of the catalyst of Example 1

[0122] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and keep stirring at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 15 minutes and wash until the washing liquid is neutral, and dry the obtained molecular sieve solid at 120 °C for 12 hours, then calcine at 550 °C for 6 hours to obtain Sample 1; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 1, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 15 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0123] Subsequently, take 15 ml of a solution containing 0.008 g of H2PtCl6·6H2O, slowly drip it into 3 g of the composite hierarchical pore molecular sieve support, and allow it to be impregnated for 12 hours. Finally, dry this solution in an oven at 120 °C for 12 hours, and then calcine at 550 °C for 3 hours. The obtained product is labeled as Catalyst 1 # . In this sample, the loading amount of the metal active component Pt is 0.1 wt%.

[0124] Preparation of the catalyst of Example 2

[0125] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and stir at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, and calcine it at 550 °C for 6 hours to obtain Sample 2; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 2, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0126] Subsequently, take 15 ml of a solution containing 0.024 g of H2PtCl6·6H2O, slowly drop it into 3 g of the composite hierarchical pore molecular sieve support, and let it impregnate for 12 hours. Finally, dry this solution in an oven at 120 °C for 12 hours, and then calcine it at 550 °C for 3 hours. The obtained product is labeled as Catalyst 2 # . In this sample, the loading amount of the metal active component Pt is 0.3 wt%.

[0127] Preparation of the Catalyst in Example 3

[0128] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and stir at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, calcine it at 550 °C at 4000 r / min for 6 hours to obtain Sample 3; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 3, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge for 5 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0129] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to impregnate for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours. The resulting product was labeled as Catalyst 3 # . In this sample, the loading amount of the metal active component Pt was 0.5 wt%.

[0130] Preparation of the catalyst in Example 4

[0131] 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L was taken and heated to 65 °C in a water bath. Then 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35) was added and stirred at 65 °C for 25 minutes. Subsequently, 1.0934 g of cetyltrimethylammonium bromide was added and stirring was continued for 5 minutes. This mixture was then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, it was washed by centrifugation at 4000 r / min for 5 minutes until the washing liquid was neutral, and the obtained molecular sieve solid was dried at 120 °C for 12 hours and then calcined at 550 °C for 6 hours to obtain Sample 4; 120 ml of a 0.8 mol / L ammonium nitrate solution was taken, heated to 85 °C, 6 g of Sample 4 was added, and stirring and exchange were carried out for 2 h. The exchange was repeated 3 times, followed by centrifugation at 4000 r / min for 5 minutes for washing, drying at 120 °C for 12 h, and finally calcining at 550 °C for 3 h to prepare the composite hierarchical pore molecular sieve.

[0132] Subsequently, 15 ml of a solution containing 0.08 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to impregnate for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours. The resulting product was labeled as Catalyst 4 # . In this sample, the loading amount of the metal active component Pt was 1 wt%.

[0133] Preparation of the catalyst in Example 5

[0134] Take 60 ml of an aqueous NaOH solution with a concentration of 1 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and keep stirring at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 15 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, and calcine it at 550 °C for 6 hours to obtain Sample 5; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 5, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 15 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0135] Subsequently, take 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O, slowly drip it into 3 g of the composite hierarchical pore molecular sieve support, and let it soak for 12 hours. Finally, dry this solution in an oven at 120 °C for 12 hours, and then calcine it at 550 °C for 3 hours. The obtained product is labeled as Catalyst 5 # . In this sample, the loading amount of the metal active component Pt is 0.5 wt%.

[0136] Preparation of the catalyst in Example 6

[0137] Take 60 ml of an aqueous NaOH solution with a concentration of 1.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and keep stirring at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 15 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, and calcine it at 550 °C for 6 hours to obtain Sample 6; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 6, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 15 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0138] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours, and the resulting product was labeled as Catalyst 6 # . In this sample, the loading amount of the metal active component Pt was 0.35 wt%.

[0139] Preparation of the catalyst of Example 7

[0140] 60 ml of an aqueous NaOH solution with a concentration of 2 mol / L was taken and heated to 65 °C in a water bath. Then 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35) was added and stirred at 65 °C for 25 minutes. Subsequently, 1.0934 g of cetyltrimethylammonium bromide was added and stirring continued for 5 minutes. This mixture was then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, it was washed by centrifugation at 4000 r / min for 5 minutes until the washing liquid was neutral, and the obtained molecular sieve solid was dried at 120 °C for 12 hours and then calcined at 550 °C for 6 hours to obtain Sample 7; 120 ml of a 0.8 mol / L ammonium nitrate solution was taken, heated to 85 °C, 6 g of Sample 7 was added, and stirring and exchange were carried out for 2 h, and the exchange was repeated 3 times. Centrifugation was carried out at a speed of 4000 r / min for 5 minutes for washing, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to prepare the composite hierarchical pore molecular sieve.

[0141] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours, and the resulting product was labeled as Catalyst 7 # . In this sample, the loading amount of the metal active component Pt was 0.5 wt%.

[0142] Preparation of the catalyst of Example 8

[0143] Take 60 ml of an aqueous NaOH solution with a concentration of 3 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and stir at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 15 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, and calcine it at 550 °C for 6 hours to obtain Sample 8; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 8, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 15 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0144] Subsequently, take 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O, slowly drip it into 3 g of the composite hierarchical pore molecular sieve support, and let it soak for 12 hours. Finally, dry this solution in an oven at 120 °C for 12 hours, and then calcine it at 550 °C for 3 hours. The obtained product is labeled as Catalyst 8 # . In this sample, the loading amount of the metal active component Pt is 0.5 wt%.

[0145] Preparation of Catalyst in Example 9

[0146] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and stir at 65 °C for 25 minutes. Subsequently, add 2.1868 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 15 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, and calcine it at 550 °C for 6 hours to obtain Sample 9; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 9, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 15 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0147] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support, and it was allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours, and then calcined at 550 °C for 3 hours. The obtained product was labeled as Catalyst 9 # . In this sample, the loading amount of the metal active component Pt was 0.5 wt%.

[0148] Preparation of the Catalyst of Example 10

[0149] 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L was taken and heated to 65 °C in a water bath. Then 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35) was added, and it was stirred at 65 °C for 25 minutes. Subsequently, 3.2802 g of cetyltrimethylammonium bromide was added, and stirring was continued for 5 minutes. This mixture was then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, it was washed by centrifugation at 4000 r / min for 5 minutes until the washing liquid was neutral, and the obtained molecular sieve solid was dried at 120 °C for 12 hours and then calcined at 550 °C for 6 hours to obtain Sample 10; 120 ml of a 0.8 mol / L ammonium nitrate solution was taken, heated to 85 °C, 6 g of Sample 10 was added, and stirring and exchange were carried out for 2 h. The exchange was repeated 3 times, and it was washed by centrifugation at a rotation speed of 4000 r / min for 5 minutes, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to prepare the composite hierarchical pore molecular sieve.

[0150] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support, and it was allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours, and then calcined at 550 °C for 3 hours. The obtained product was labeled as Catalyst 10 # . In this sample, the loading amount of the metal active component Pt was 0.5 wt%.

[0151] Preparation of the Catalyst of Example 11

[0152] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 80 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and stir at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 15 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, and calcine it at 550 °C for 6 hours to obtain Sample 11; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 11, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 15 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0153] Subsequently, take 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O, slowly drip it into 3 g of the composite hierarchical pore molecular sieve support, and let it soak for 12 hours. Finally, dry this solution in an oven at 120 °C for 12 hours, and then calcine it at 550 °C for 3 hours. The obtained product is labeled as Catalyst 11 # . In this sample, the loading amount of the metal active component Pt is 0.5 wt%.

[0154] Preparation of Catalyst in Example 12

[0155] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 100), and stir at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 15 minutes and wash until the washing liquid is neutral. Then dry the obtained molecular sieve solid at 120 °C for 12 hours, and calcine it at 550 °C for 6 hours to obtain Sample 12; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 12, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 15 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0156] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours, and the resulting product was labeled as Catalyst 12 # . In this sample, the loading of the metal active component Pt was 0.5 wt%.

[0157] Preparation of the Catalyst of Example 13

[0158] 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L was taken and heated to 65 °C in a water bath. Then 2 g of ZSM-5 microporous molecular sieve (Si / Al = 500) was added and stirred at 65 °C for 25 minutes. Subsequently, 1.0934 g of cetyltrimethylammonium bromide was added and stirring continued for 5 minutes. This mixture was then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, it was washed by centrifugation at 4000 r / min for 5 minutes until the washing liquid was neutral, and the obtained molecular sieve solid was dried at 120 °C for 12 hours and then calcined at 550 °C for 6 hours to obtain Sample 13; 120 ml of a 0.8 mol / L ammonium nitrate solution was taken, heated to 85 °C, 6 g of Sample 13 was added, stirred and exchanged for 2 h, and the exchange was repeated 3 times. It was washed by centrifugation at a speed of 4000 r / min for 5 minutes, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to prepare the composite hierarchical pore molecular sieve.

[0159] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours, and the resulting product was labeled as Catalyst 13 # . In this sample, the loading of the metal active component Pt was 0.5 wt%.

[0160] Preparation of the Catalyst of Example 14

[0161] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 800), and keep stirring at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 12 hours. After completion, centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral, and dry the obtained molecular sieve solid at 120 °C for 12 hours, then calcine it at 550 °C for 6 hours to obtain Sample 14; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 14, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0162] Subsequently, take 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O, slowly drop it into 3 g of the composite hierarchical pore molecular sieve support, and let it soak for 12 hours. Finally, dry this solution in an oven at 120 °C for 12 hours, then calcine it at 550 °C for 3 hours, and the obtained product is labeled as Catalyst 14 # . In this sample, the loading amount of the metal active component Pt is 0.5 wt%.

[0163] Preparation of the Catalyst in Example 15

[0164] Take 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L and heat it to 65 °C in a water bath. Then add 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35), and keep stirring at 65 °C for 25 minutes. Subsequently, add 1.0934 g of cetyltrimethylammonium bromide and continue stirring for 5 minutes. This mixture is then transferred to a hydrothermal reaction kettle and recrystallized at 100 °C for 12 hours. After completion, centrifuge at 4000 r / min for 5 minutes and wash until the washing liquid is neutral, and dry the obtained molecular sieve solid at 120 °C for 12 hours, then calcine it at 550 °C for 6 hours to obtain Sample 15; take 120 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 6 g of Sample 15, stir and exchange for 2 h, repeat the exchange 3 times, centrifuge at 4000 r / min for 5 minutes and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to prepare a composite hierarchical pore molecular sieve.

[0165] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours, and the resulting product was labeled as Catalyst 15 # . In this sample, the loading amount of the metal active component Pt was 0.5 wt%.

[0166] Preparation of the Catalyst in Example 16

[0167] 60 ml of an aqueous NaOH solution with a concentration of 0.5 mol / L was taken and heated to 65 °C in a water bath. Then 2 g of ZSM-5 microporous molecular sieve (Si / Al = 35) was added and stirred at 65 °C for 25 minutes. Subsequently, 1.0934 g of cetyltrimethylammonium bromide was added and stirring was continued for 5 minutes. This mixture was then transferred to a hydrothermal reaction kettle and recrystallized at 120 °C for 24 hours. After completion, it was washed by centrifugation at 4000 r / min for 5 minutes until the washing liquid was neutral, and the obtained molecular sieve solid was dried at 120 °C for 12 hours and then calcined at 550 °C for 6 hours to obtain Sample 16; 120 ml of a 0.8 mol / L ammonium nitrate solution was taken, heated to 85 °C, 6 g of Sample 16 was added, and stirring and exchange were carried out for 2 h, and the exchange was repeated 3 times. Centrifugation was carried out at 4000 r / min for 5 minutes for washing, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to prepare the composite hierarchical pore molecular sieve.

[0168] Subsequently, 15 ml of a solution containing 0.04 g of H2PtCl6·6H2O was slowly added dropwise to 3 g of the composite hierarchical pore molecular sieve support and allowed to soak for 12 hours. Finally, this solution was dried in an oven at 120 °C for 12 hours and then calcined at 550 °C for 3 hours, and the resulting product was labeled as Catalyst 16 # . In this sample, the loading amount of the metal active component Pt was 0.5 wt%.

[0169] Test Example 16

[0170] For the catalysts 1 # ~16 # in the examples, nitrogen physical adsorption-desorption and pore size distribution analysis were carried out, and the pore specific surface area was calculated based on the obtained nitrogen physical adsorption-desorption curve, and the pore size was calculated based on the obtained pore size distribution curve.

[0171] Taking Catalyst 3 # as a typical representative, its nitrogen physical adsorption-desorption curve and pore size distribution curve are shown in Figure 1, where (a) is the physical adsorption and desorption curve of nitrogen, and (b) is the pore size distribution curve. According to Figure 1 Catalyst 1 # has a micropore specific surface area of 160 m 2 / g, a micropore volume of 0.06 cm 3 / g, a mesopore specific surface area of 345 m 2 / g, a mesopore volume of 0.50 cm 3 / g, and a mesopore diameter of 3 - 10 nm.

[0172] Reaction evaluation of the catalyst in Example 17

[0173] Apply the above - obtained Catalyst 1 # -16 # to the dehydrogenation reaction of methylcyclohexane, and the reaction conditions are shown in Table 1.

[0174] Pre - treatment before the reaction: Heat up from room temperature to 200 - 500 °C at a heating rate of 3 °C / min under N2 (30 ml / min), keep it for 30 - 60 minutes, then switch to H2 (100 ml / min) and turn off N2. After reduction for 1 - 3 hours, switch back to N2 (30 ml / min), turn off H2 and cool down to the reaction temperature. Finally, the system is ready for the subsequent reaction, and cyclohexane is introduced.

[0175] Table 1 Catalyst 1 # -16 # Reaction conditions and results for the dehydrogenation reaction of methylcyclohexane

[0176]

[0177]

[0178] The above are only several embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A hierarchical pore molecular sieve, characterized in that, The silica-alumina ratio of the hierarchical pore molecular sieve is 20 to 1000; The hierarchical pore molecular sieve has micropores and mesopores; The micropore specific surface area of the hierarchical zeolite is 100 to 300 m 2 / g, and the micropore volume is 0.03 to 0.20 cm 3 / g; The mesoporous specific surface area of the hierarchical zeolite is 150 to 500 m 2 / g, and the mesoporous volume is 0.20 to 0.60 cm 3 / g.

2. The hierarchical pore molecular sieve according to claim 1, characterized in that, The mesopore aperture of the hierarchical pore molecular sieve is 3 to 12 nm.

3. A preparation method of the hierarchical pore molecular sieve according to any one of claims 1 to 2, characterized in that, The preparation method includes: (1) After subjecting the molecular sieve to alkali treatment in an alkali solution, adding it to a solution containing a surfactant for hydrothermal reaction, centrifuging I, drying I, and calcining I to obtain an intermediate; (2) Subjecting the intermediate obtained in step (1) to ammonium exchange, centrifuging II, drying II, and calcining II to obtain the hierarchical pore molecular sieve.

4. The preparation method according to claim 3, characterized in that, The molecular sieve is selected from any one of ZSM-5 molecular sieve, Beta molecular sieve, and ZSM-11 molecular sieve; Preferably, in step (1), the alkaline substance in the alkali solution is selected from at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate; In the alkali solution, the concentration of the alkaline substance is 0.1 to 3 mol / L; The solid-liquid ratio of the molecular sieve to the alkali solution is 1:10 to 50 g / ml; Preferably, the surfactant is selected from at least one of dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide; In the solution containing the surfactant, the concentration of the surfactant is 0.05 to 0.3 mol / L.

5. The preparation method according to claim 3, characterized in that, In step (1), the temperature of the alkali treatment is 30 to 90 °C; The time of the alkali treatment is 10 to 60 minutes; Preferably, the temperature of the hydrothermal reaction is 60 to 120 °C; The time of the hydrothermal reaction is 12 to 36 hours; Preferably, the rotation speed of the centrifuging I is 4000 revolutions; The time of the centrifuging I is 5 minutes; Preferably, the temperature of the drying I is 60 to 120 °C; The time of the drying I is 10 to 24 hours; Preferably, the temperature of the calcining I is 500 to 700 °C; The time of the calcining I is 2 to 8 hours.

6. The preparation method according to claim 3, characterized in that, In step (2), the ammonium salt solution used for the ammonium exchange is an ammonium nitrate solution; In the ammonium nitrate solution, the concentration of ammonium nitrate is 0.2 to 1 mol / L; The solid-liquid ratio of the intermediate to the ammonium nitrate solution is 1:10 to 30 g / ml; Preferably, the temperature of the ammonium exchange is 70 to 90 °C; The time of the ammonium exchange is 1 to 3 hours; The number of repeated exchanges of the ammonium exchange is 2 to 6 times; Preferably, the rotation speed of the centrifuging II is 4000 revolutions; The time of the centrifuging II is 5 minutes; Preferably, the temperature of the drying II is 100 to 120 °C; The time of the drying II is 10 to 24 hours; Preferably, the temperature of the calcining II is 400 to 600 °C; The time of the calcining II is 2 to 5 hours.

7. A cycloalkane dehydrogenation catalyst, characterized in that, The naphthene dehydrogenation catalyst includes a carrier and an active component; The carrier is selected from the hierarchical pore molecular sieve according to any one of claims 1 to 2; The active component includes an active element, and the active element is selected from at least one of Pt, Pd, and Rh; The active component accounts for 0.01 to 10 wt% of the mass of the hierarchical pore molecular sieve.

8. A method for preparing the cycloalkane dehydrogenation catalyst according to claim 7, characterized in that, The preparation method includes: An aqueous solution containing a precursor of the active component is impregnated in excess onto the hierarchical porous molecular sieve, dried III, and calcined III to obtain the naphthene dehydrogenation catalyst; Preferably, the precursor of the active component is selected from at least one of H2PtCl6, PdCl2, and RhCl3; The mass ratio of the hierarchical porous molecular sieve to the volume of the aqueous solution containing the precursor of the active component is 1:5 to 10 g / ml; Preferably, the impregnation time is 12 to 24 hours; Preferably, the drying III temperature is 60 to 120 °C; The drying III time is 10 to 24 hours; Preferably, the calcination III temperature is 500 to 700 °C; The calcination III time is 2 to 8 hours.

9. A method for cycloalkane dehydrogenation, characterized in that, A raw material containing naphthene is contacted with the pre-reduced catalyst in a fixed-bed reaction tube for reaction to obtain hydrogen and dehydrogenation products; The catalyst is the naphthene dehydrogenation catalyst described in claim 7.

10. The method according to claim 9, characterized in that, The pre-reduction time is 1 to 3 hours, the pre-reduction temperature is 200 to 500 °C, and the pre-reduction is carried out in an H2 atmosphere; Preferably, the reaction is carried out in an inert atmosphere; The inert atmosphere is selected from at least one of N2 and Ar; The weight hourly space velocity of the raw material containing naphthenes is 2 to 12 h -1 ; The pressure of the reaction is 0.1 MPa; The temperature of the reaction is 200 to 700 °C.

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