Method for quickly adjusting layer spacing of layered molecular sieve and application thereof

Abstract

The application discloses a method for quickly regulating layer spacing of a layered molecular sieve and application thereof. The method is characterized by using tetraethyl silicate condensate, tetrabutyl titanate silane and ferrocene silane as intercalation reagents, making a carrier gas carry vaporized intercalation reagents to flow through a reactor loaded with the layered molecular sieve, making the carrier gas carry vaporized deionized water to flow through the reactor loaded with the layered molecular sieve, and then performing calcination on the layered molecular sieve to obtain a pillared post-molecular sieve with good thermal stability. The application adopts gas phase pillaring, and has the advantages of simple preparation method, mild conditions, small amount of raw materials, simple steps, high yield, easy scale production, and the like. The intercalation reagent improves the high-temperature tolerance of the original layered molecular sieve, and at the same time, a plurality of active sites and places for adsorption of reactants are introduced at one time. The pillared post-molecular sieve is used in a reaction of preparing epoxycyclooctane by oxidizing cyclooctene with hydrogen peroxide, and the reaction has a cyclooctene conversion rate of 43% or more and an epoxycyclooctane selectivity of 65% or more.

Description

Technical Field

[0001] This invention belongs to the field of molecular sieves, specifically relating to a method for rapidly adjusting the interlayer spacing of layered molecular sieves and imparting them with temperature and environmental tolerance. Background Technology

[0002] Molecular sieves, due to their unique structure and properties, are widely used in industrial production, such as catalysis and separation. In particular, their unique microporous structure plays a crucial role in type-selective catalysis. Historically, naturally formed molecular sieves were first discovered in volcanic crater areas, formed by geological movements and resulting geothermal activity. They are composed of aluminosilicates, hence the name zeolite. With increasingly demanding production and application requirements, naturally formed molecular sieves have gradually become insufficient to meet specific structural and compositional requirements, thus artificially synthesized molecular sieves have become the mainstay of applications. Among these, MFI-type molecular sieves are one of the most widely used and extensively studied. Their excellent thermal stability and suitable pore structure are crucial in petrochemical reactions such as catalytic cracking, toluene disproportionation, and methanol-to-olefins.

[0003] The exploration of porous materials has progressed alongside the accumulation of social knowledge and the development of technology, while also responding to increasing demands. Research on porous materials often focuses on thermodynamics and kinetics, aiming to control the pore structure. Early porous materials were mostly simple pore types, such as microporous materials. While micropores fulfilled their primary function, they also presented some problems. For example, in reactions involving larger molecules, diffusion difficulties arose due to their large molecular radii, or products or carbon deposits could not be desorbed in time, leading to decreased yield and reduced lifespan. In recent years, hierarchical porous materials have attracted considerable attention from academia and industry due to their unique pore structure.

[0004] To address the aforementioned problems encountered in practical applications and to obtain molecular sieve materials with well-developed pores and high stability, hierarchical porous molecular sieves have emerged. Compared to traditional microporous molecular sieves, hierarchical porous molecular sieves not only retain the original well-developed microporous system but also introduce mesoporous and even macroporous structures with interlayered pores into the pore system. This preserves the functionality of the micropores while avoiding diffusion difficulties caused by excessively small pore sizes, thus improving the lifespan and catalytic activity of catalysts. Structurally, the mesoporous structure exists in the form of interlayered pores. When the thickness of the monolayer structure decreases to the nanometer scale, it can be defined as a two-dimensional layered molecular sieve. The emergence of two-dimensional layered molecular sieves not only improves application efficiency and broadens application fields but also opens a door to a multitude of possibilities, guiding the exploration of other hierarchical porous materials.

[0005] Extensive research and practice have also revealed some pressing issues. For example, the mesoporous structure of layered molecular sieves, i.e., the interlayer spacing, is due to the presence of organic template agents, thus lacking high temperature and environmental tolerance. Secondly, the interlayer spacing also needs to be adjusted according to the size of reactant or product molecules. Therefore, in summary, hierarchical porous molecular sieves with interlayer spacing that can flexibly match the actual molecular size of the reactants while maintaining a certain level of environmental tolerance are highly valuable. Summary of the Invention

[0006] This invention addresses the problems of low reaction efficiency and low adsorption capacity caused by molecular size mismatch between host and guest molecules in catalytic reactions or adsorption separation using molecular sieves. It provides a method for rapidly controlling the interlayer spacing of layered molecular sieves and giving them higher temperature and environmental tolerance.

[0007] The method for rapidly controlling the interlayer spacing of layered molecular sieves provided by this invention is as follows: First, a carrier gas carrying vaporized intercalation reagent flows through a reactor containing layered molecular sieves. Then, a carrier gas carrying vaporized deionized water flows through the reactor containing layered molecular sieves. Next, the layered molecular sieves are heated to 300–450°C under inert gas protection and held at this temperature for 1–4 hours. Then, the inert gas is switched to air or oxygen, and the temperature is raised to 500–650°C and held for 1–6 hours. Finally, the temperature is cooled to room temperature to obtain pillared molecular sieves. The intercalation reagent is selected from any one of tetraethyl silicate condensate, tetrabutyl titanate silane, and ferrocene silane.

[0008] The preparation method of the above-mentioned tetraethyl silicate condensate is as follows: ethanol, tetraethyl silicate and deionized water are mixed in a molar ratio of 3-5:1:3-5, and the pH of the mixed solution is adjusted to 2-3 with hydrochloric acid. The mixture is stirred at 20-50°C for 40-90 minutes, cooled to room temperature, and then deionized water of the same volume as the aforementioned deionized water and acetylacetone of 10%-30% of the aforementioned ethanol volume are added. The pH is adjusted to 2-3 with hydrochloric acid, the temperature is raised to 60-100°C, and the mixture is stirred for 20-60 minutes. The tetraethyl silicate condensate is obtained by vacuum distillation.

[0009] The preparation method of the above-mentioned tetrabutyl titanate-based silane is as follows: using acetic acid as a catalyst and ethanol as a solvent, tetrabutyl titanate and tetraethyl silicate are reacted with deionized water at 20-40°C for 4-6 hours to obtain partial hydrolysis products of tetrabutyl titanate and tetraethyl silicate, respectively, wherein the molar ratio of tetrabutyl titanate or tetraethyl silicate to acetic acid, ethanol, and deionized water is 1:4-6:8-15:8-15; the partial hydrolysis products of tetrabutyl titanate and tetraethyl silicate are mixed at a volume ratio of 1:1-3, and hydrochloric acid is added to adjust the pH of the mixed solution to 2-3. The mixture is stirred at 20-70°C for 6-8 hours, and the tetrabutyl titanate-based silane is obtained by vacuum distillation.

[0010] The preparation method of the above-mentioned ferrocene-based silane is as follows: ferrocene is added to n-hexane, stirred evenly, then tetramethylethylenediamine and n-butyllithium are added, and the mixture is stirred and reacted at -80 to -70°C for 2 to 4 hours under inert gas protection. After the reaction is completed, n-hexane is replenished to the original solution volume, and dimethylsilane is added. The mixture is stirred and reacted at 20 to 35°C for 2 to 4 hours, and the ferrocene-based silane is obtained by vacuum distillation. The molar ratio of ferrocene, tetramethylethylenediamine, n-butyllithium, and dimethylsilane is 1:1 to 1.5:2 to 3:0.5 to 1.5.

[0011] The aforementioned layered molecular sieves are selected from any one of layered MFI, layered MWW, layered FER molecular sieves, etc.

[0012] Furthermore, the intercalation reagent and deionized water are heated to 40–70°C and vaporized, then carried by a carrier gas through a reactor containing layered molecular sieves.

[0013] In the above method for rapidly controlling the interlayer spacing of layered molecular sieves, the preferred flow rate of the carrier gas is 20-50 mL / min, and the carrier gas is nitrogen; the carrier gas carries the vaporized intercalation reagent and vaporized deionized water through the reactor containing the layered molecular sieve for 1-6 hours.

[0014] Furthermore, in the above-mentioned method for rapidly adjusting the interlayer spacing of layered molecular sieves, it is preferable to heat the layered molecular sieve to 450°C at a heating rate of 8–15°C / min under inert gas protection, hold it at that temperature for 2 hours, then switch the inert gas to air or oxygen, and raise the temperature to 550°C at a heating rate of 8–15°C / min, and hold it for 3–4 hours.

[0015] The present invention also provides the use of the pillared molecular sieve obtained by the above method in the catalytic oxidation of cyclooctene with hydrogen peroxide to prepare cyclooctane oxide. The specific method is as follows: the pillared molecular sieve is ground and pressed into tablets to 40-60 mesh, and mixed with an equal mass of quartz sand. The mixture is then loaded into the catalyst bed of a fixed-bed reactor. Hydrogen peroxide and cyclooctene are simultaneously pumped into the fixed-bed reactor using injection pumps. The flow rate of hydrogen peroxide is set to 0.5-5 mL / min, and the flow rate of cyclooctene is set to 0.5-10 mL / min. The reactor temperature is 50-90℃.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. This invention uses tetraethyl silicate condensate, tetrabutyl titanate silane, and ferrocene silane as intercalation reagents to change the hydrophilicity of molecular sieves, improve the high temperature resistance and environmental resistance of the original layered molecular sieves (such as better hydrothermal stability), and introduce multiple active sites and sites for reactant adsorption at one time. In addition, the compressive strength of the molecular sieve is enhanced, the slippage between layers is reduced, and it is easier to form.

[0018] 2. This invention employs a gas-phase method, where a carrier gas carries vaporized intercalation reagents and vaporized deionized water into the interlayer space of the molecular sieve. The hydrolysis rate of the intercalation reagent is adjusted by controlling the amount, temperature, and time of the intercalation reagent. After calcination, the interlayer spacing can be controlled, resulting in a pillared molecular sieve with good thermal stability. This invention features mild preparation conditions, uses small amounts of raw materials, eliminates the need for hydrolysis before calcination, and avoids drying processes, making the process simple and yielding high output. Compared to the liquid-phase pillaring method, it requires less intercalation reagent, is faster, and is scalable, with lower equipment requirements, making it easy to scale up production and possessing significant commercial application potential. Environmentally, the absence of organic template agents also improves acid and alkali resistance.

[0019] 3. This invention relates to a pillared molecular sieve-catalyzed reaction of hydrogen peroxide oxidizing cyclooctene to prepare cyclooctane oxide. This reaction itself requires mesoporous structures due to molecular size (asymmetric oxidation, the main reaction). The pillared molecular sieve provides the reaction site and can also provide different metal active sites depending on the intercalation reagent. Furthermore, the degree of thermal and catalytic decomposition of hydrogen peroxide (the latter two side reactions) can be controlled by adjusting temperature and pressure. The catalytic activity is high, with a cyclooctene conversion rate exceeding 43% and a cyclooctane oxide selectivity exceeding 65%. Attached Figure Description

[0020] Figure 1 This is a scanning electron microscope image of the columnar layered MFI molecular sieve from Example 1.

[0021] Figure 2 These are the small-angle and wide-angle X-ray diffraction patterns of the columnar layered MFI molecular sieves in Examples 1-3.

[0022] Figure 3 These are the small-angle and wide-angle X-ray diffraction patterns of the columnar layered MWW molecular sieves in Examples 4-6.

[0023] Figure 4 These are the small-angle and wide-angle X-ray diffraction patterns of the pillared layered MWW molecular sieves of Examples 4-5 and Comparative Examples 1-2.

[0024] Figure 5 These are the nitrogen low-temperature adsorption-desorption curves and pore size distribution curves of the columnar layered MFI molecular sieves in Examples 1-3.

[0025] Figure 6 These are the nitrogen low-temperature adsorption-desorption curves and pore size distribution curves of the columnar MWW molecular sieves after Examples 4-6.

[0026] Figure 7 The thermogravimetric curves are those of the layered MFI molecular sieves before and after pillaring in Example 1.

[0027] Figure 8The graphs show the conversion and selectivity of cyclooctene to cyclooxygenate catalyzed by hydrogen peroxide oxidation using pillared layered molecular sieves in Examples 1-6 and Comparative Examples 1-2. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0029] Example 1

[0030] 1. Preparation of intercalation reagents

[0031] 46 g (1 mol) of ethanol, 52 mL (0.25 mol) of tetraethyl silicate and 18 mL (1 mol) of deionized water were mixed, and the pH of the mixture was adjusted to 2-3 with hydrochloric acid. The mixture was stirred at 50 °C for 60 minutes, cooled to room temperature, and then 18 mL of deionized water and 5 mL of acetylacetone were added. The pH was adjusted to 2-3 with hydrochloric acid, the temperature was raised to 80 °C, and the mixture was stirred for 30 minutes. The tetraethyl silicate condensate was obtained by vacuum distillation.

[0032] 2. Pillared molecular sieves

[0033] 30 mL of tetraethyl silicate condensate was placed into a 50 mL reagent bottle with a long inlet and short outlet tubing. The long tubing of the reagent bottle was submerged below the surface of the tetraethyl silicate condensate, while the short tubing was above the surface. Nitrogen gas was introduced at a flow rate of 30 mL / min. The tetraethyl silicate condensate was heated and maintained at 60°C, allowing nitrogen to act as a carrier gas, carrying the vaporized tetraethyl silicate condensate through the tubing into a reactor containing layered MFI molecular sieves, ensuring full contact with the molecular sieves. The nitrogen gas introduction time was 2 hours. Afterward, the nitrogen gas was switched to a reagent bottle containing deionized water. Inside the bottle, deionized water was heated and maintained at 60°C. Using the same method described above, nitrogen gas carrying water vapor was introduced into the reactor containing the layered MFI molecular sieve, ensuring full contact with the sieve. The nitrogen gas introduction time was 4 hours. Finally, nitrogen gas was directly switched into the reactor, and using nitrogen as a protective gas, the reactor was heated to 450°C at a heating rate of 10°C / min and held for 2 hours. Then, nitrogen was switched to oxygen, and the reactor was heated to 550°C and held for 4 hours. After cooling to room temperature, the column-supported layered MFI molecular sieve was obtained (see...). Figure 1 ).

[0034] Example 2

[0035] 1. Preparation of intercalation reagents

[0036] 17 g (0.05 mol) of tetrabutyl titanate, 15 g (0.25 mol) of acetic acid, 23 g (0.5 mol) of ethanol, and 9 g (0.5 mol) of deionized water were mixed and stirred at 30 °C for 5 hours to obtain a partially hydrolyzed product of tetrabutyl titanate. 10.4 g (0.05 mmol) of tetraethyl silicate, 15 g (0.25 mol) of acetic acid, 23 g (0.5 mol) of ethanol, and 9 g (0.5 mol) of deionized water were mixed and stirred at 30 °C for 5 hours to obtain a partially hydrolyzed product of tetraethyl silicate. 15 mL of the partially hydrolyzed product of tetrabutyl titanate was mixed with 15 mL of the partially hydrolyzed product of tetraethyl silicate, and hydrochloric acid was added to adjust the pH of the mixed solution to 2–3. The mixture was stirred at 50 °C for 6 hours, and then distilled under reduced pressure to obtain tetrabutyl titanate silane.

[0037] 2. Pillared molecular sieves

[0038] 30 mL of tetrabutyl titanate silane was placed into a 50 mL reagent bottle with a long inlet and a short outlet tube. The long tube of the reagent bottle was submerged below the surface of the tetrabutyl titanate silane, while the short tube was above the surface. Nitrogen gas was introduced at a flow rate of 30 mL / min. The tetrabutyl titanate silane was heated and maintained at 60°C, allowing the nitrogen gas to carry the vaporized tetrabutyl titanate silane through the tube into a reactor containing layered MFI molecular sieves, ensuring full contact with the molecular sieves. The nitrogen gas introduction time was 4 hours. The other steps in this process were the same as step 2 in Example 1, resulting in a column-supported layered MFI molecular sieve.

[0039] Example 3

[0040] 1. Preparation of intercalation reagents

[0041] 18.6 g (0.1 mol) of ferrocene was added to 86 mL of n-hexane and stirred until homogeneous. Then, 11.6 g (0.1 mol) of tetramethylethylenediamine and 12.8 g (0.2 mol) of n-butyllithium were added. The mixture was stirred at -78 °C for 3 hours under nitrogen protection. After the reaction was completed, the volume of n-hexane was replenished to the original volume, and 6 g (0.1 mol) of dimethylsilane was added. The mixture was stirred at 30 °C for 3 hours, and the ferrocene-based silane was obtained by vacuum distillation.

[0042] 2. Pillared molecular sieves

[0043] 30 mL of ferrocene-based silane was placed into a 50 mL reagent bottle with a long inlet and a short outlet tube. The long tube of the reagent bottle was submerged below the surface of the ferrocene-based silane, while the short tube was above the surface. Nitrogen gas was introduced and the flow rate was set to 30 mL / min. The ferrocene-based silane was heated and maintained at 60°C, so that the nitrogen gas carried the vaporized ferrocene-based silane through the tube into the reactor containing the layered MFI molecular sieve and made full contact with the molecular sieve. The nitrogen gas was introduced for 4 hours. The other steps in this process were the same as step 2 in Example 1, resulting in a column-supported layered MFI molecular sieve.

[0044] Example 4

[0045] 1. Preparation of intercalation reagents

[0046] Tetraethyl silicate condensate was prepared according to the method in step 1 of Example 1.

[0047] 2. Pillared molecular sieves

[0048] In this step, the layered MFI molecular sieve in step 2 of Example 1 is replaced with a layered MWW molecular sieve, and the other steps are the same as step 2 of Example 1, to obtain a pillared layered MWW molecular sieve.

[0049] Example 5

[0050] 1. Preparation of intercalation reagents

[0051] Tetraethyl silicate condensate was prepared according to the method in step 1 of Example 1.

[0052] 2. Pillared molecular sieves

[0053] In this step, the layered MFI molecular sieve in step 2 of Example 1 is replaced with a layered MWW molecular sieve, and the other steps are the same as step 2 of Example 1, to obtain a pillared layered MWW molecular sieve.

[0054] Example 6

[0055] 1. Preparation of intercalation reagents

[0056] Tetraethyl silicate condensate was prepared according to the method in step 1 of Example 1.

[0057] 2. Pillared molecular sieves

[0058] In this step, the layered MFI molecular sieve in step 2 of Example 1 is replaced with a layered MWW molecular sieve, and the other steps are the same as step 2 of Example 1, to obtain a pillared layered MWW molecular sieve.

[0059] Comparative Example 1

[0060] 30 mL of tetraethyl silicate was placed into a 50 mL reagent bottle with a long inlet and a short outlet tube. The long tube of the reagent bottle was submerged below the surface of the tetraethyl silicate liquid, while the short tube was above the liquid surface. Nitrogen gas was introduced and the flow rate was set to 30 mL / min. The tetraethyl silicate was heated and maintained at 60°C, so that the nitrogen gas, as a carrier gas, carried the vaporized tetraethyl silicate through the tube into the reactor containing the layered MWW molecular sieve and made full contact with the molecular sieve. The nitrogen gas was introduced for 4 hours. The other steps in this process were the same as step 2 in Example 1, resulting in a column-supported layered MWW molecular sieve.

[0061] Comparative Example 2

[0062] 30 mL of tetrabutyl titanate was placed into a 50 mL reagent bottle with a long inlet and a short outlet tube. The long tube of the reagent bottle was submerged below the surface of the tetrabutyl titanate liquid, while the short tube was above the liquid surface. Nitrogen gas was introduced and the flow rate was set to 30 mL / min. The tetrabutyl titanate was heated and maintained at 60°C, so that the nitrogen gas, as a carrier gas, carried the vaporized tetrabutyl titanate through the tube into the reactor containing the layered MWW molecular sieve and made full contact with the molecular sieve. The nitrogen gas was introduced for 4 hours. The other steps in this process were the same as step 2 in Example 1, resulting in a column-supported layered MWW molecular sieve.

[0063] The structure of the pillared layered molecular sieves prepared in Examples 1-6 and Comparative Examples 1-2 was characterized, and the results are shown in Tables 1-5. Figures 2-6 .

[0064] Table 1. Interlayer spacing of pillared layered molecular sieves in Examples 1-3

[0065]

[0066] Table 2. Interlayer spacing of the columnar layered molecular sieves in Examples 4-6

[0067]

[0068] Table 3 Comparison of interlayer spacing of pillared layered molecular sieves in Examples 4-5 and Comparative Examples 1-2

[0069]

[0070] Table 4. Textural information of the columnar layered molecular sieves in Examples 1-3

[0071]

[0072] Table 5. Textural information of the post-pillared layered molecular sieves in Examples 4-6.

[0073]

[0074] From Tables 1-3 and Figures 2-4It can be seen that the interlayer spacing of the pillared layered MFI molecular sieve increases, with a maximum increase of 0.4 nm compared to before pillaring. Similarly, the interlayer spacing of the pillared layered MWW molecular sieve also increases, with a maximum increase of 1.3 nm. Furthermore, the pillared layered molecular sieve exhibits multiple diffraction peaks in the small-angle range, indicating that the pillared layered structure is more regular and has better long-range order. The changes in mesopore volume in Tables 4 and 5 are due to the increased interlayer spacing, and the specific surface area also increases accordingly. Figure 5 and Figure 6 The adsorption-desorption curves and pore size distribution curves in the data can both serve as evidence for this.

[0075] Thermogravimetric analysis was performed on the layered MFI molecular sieves before and after the pillar support in Example 1 above. Figure 7 It can be observed that the temperature tolerance of the layered MFI molecular sieve after pillar support is significantly improved.

[0076] Application Example 1

[0077] 0.1 g of pillared molecular sieve was weighed, ground, and pressed into tablets to 60 mesh. This tablet was then mixed with an equal mass of quartz sand and slowly packed into a tubular stainless steel reactor with a diameter of 6 mm and a length of 400 mm. Quartz wool was placed above and below the catalyst bed to fix it in the middle of the reactor. Hydrogen peroxide and cyclooctene were then simultaneously pumped into the reactor using syringe pumps, with the hydrogen peroxide flow rate set at 0.5 mL / min and the cyclooctene flow rate at 0.2 mL / min, respectively. The reactor temperature was 60 °C. Samples were taken and tested after 2 hours of reaction. The results are shown below. Figure 8 .

[0078] from Figure 8 The results show that the catalytic activity of the pillared layered molecular sieves in Examples 1-6 is better than that in Comparative Examples 1 and 2, with higher conversion rates of cyclooctene and higher selectivity for epoxides. This indicates that using the intercalation reagent pillar of the present invention not only provides more mesoporous space for the main reaction to occur, but also that the metal substances in the intercalation reagent can create certain active sites to promote the reaction.

Claims

1. A method for rapidly controlling the interlayer spacing of layered molecular sieves, characterized in that: Using an airflow-driven method, the carrier gas first carries vaporized intercalation reagents through a reactor containing layered molecular sieves. Then, the carrier gas carries vaporized deionized water through the reactor containing layered molecular sieves. The layered molecular sieves are then heated to 300–450 °C under inert gas protection and held at that temperature for 1–4 hours. The inert gas is then switched to air or oxygen, and the temperature is raised to 500–650 °C and held for 1–6 hours. Finally, the temperature is cooled to room temperature to obtain the pillared molecular sieve. The intercalation reagent is selected from tetraethyl silicate condensate; The preparation method of the tetraethyl silicate condensate is as follows: ethanol, tetraethyl silicate, and deionized water are mixed in a molar ratio of 3-5:1:3-5, and the pH of the mixed solution is adjusted to 2-3 with hydrochloric acid. The mixture is stirred at 20-50 °C for 40-90 minutes, cooled to room temperature, and then deionized water of the same volume as the aforementioned deionized water and acetylacetone of 10%-30% of the aforementioned ethanol volume are added. The pH is adjusted to 2-3 with hydrochloric acid, the temperature is raised to 60-100 °C, and the mixture is stirred for 20-60 minutes. The tetraethyl silicate condensate is obtained by vacuum distillation.

2. A method for rapidly controlling the interlayer spacing of layered molecular sieves, characterized in that: Using an airflow-driven method, the carrier gas first carries vaporized intercalation reagents through a reactor containing layered molecular sieves. Then, the carrier gas carries vaporized deionized water through the reactor containing layered molecular sieves. The layered molecular sieves are then heated to 300–450 °C under inert gas protection and held at that temperature for 1–4 hours. The inert gas is then switched to air or oxygen, and the temperature is raised to 500–650 °C and held for 1–6 hours. Finally, the temperature is cooled to room temperature to obtain the pillared molecular sieve. The intercalation reagent is selected from tetrabutyl titanate silane; The preparation method of the tetrabutyl titanate-based silane is as follows: using acetic acid as a catalyst and ethanol as a solvent, tetrabutyl titanate and tetraethyl silicate are reacted with deionized water at 20-40 °C for 4-6 hours to obtain partial hydrolysis products of tetrabutyl titanate and tetraethyl silicate, respectively, wherein the molar ratio of tetrabutyl titanate or tetraethyl silicate to acetic acid, ethanol, and deionized water is 1:4-6:8-15:8-15; the partial hydrolysis products of tetrabutyl titanate and tetraethyl silicate are mixed at a volume ratio of 1:1-3, and hydrochloric acid is added to adjust the pH of the mixed solution to 2-3. The mixture is stirred at 20-70 °C for 6-8 hours, and the tetrabutyl titanate-based silane is obtained by vacuum distillation.

3. A method for rapidly controlling the interlayer spacing of layered molecular sieves, characterized in that: Using an airflow-driven method, the carrier gas first carries vaporized intercalation reagents through a reactor containing layered molecular sieves. Then, the carrier gas carries vaporized deionized water through the reactor containing layered molecular sieves. The layered molecular sieves are then heated to 300–450 °C under inert gas protection and held at that temperature for 1–4 hours. The inert gas is then switched to air or oxygen, and the temperature is raised to 500–650 °C and held for 1–6 hours. Finally, the temperature is cooled to room temperature to obtain the pillared molecular sieve. The intercalation reagent is selected from ferrocene-based silanes; The method for preparing the ferrocene-based silane is as follows: ferrocene is added to n-hexane, stirred evenly, and then tetramethylethylenediamine and n-butyllithium are added. The mixture is stirred and reacted at -80 to -70 °C for 2 to 4 hours under inert gas protection. After the reaction is completed, n-hexane is replenished to the original solution volume, and dimethylsilane is added. The mixture is stirred and reacted at 20 to 35 °C for 2 to 4 hours, and then distilled under reduced pressure to obtain the ferrocene-based silane. The molar ratio of ferrocene, tetramethylethylenediamine, n-butyllithium, and dimethylsilane is 1: 1 to 1.5: 2 to 3: 0.5 to 1.

5.

4. The method for rapidly controlling the interlayer spacing of layered molecular sieves according to any one of claims 1 to 3, characterized in that: The layered molecular sieve is selected from any one of layered MFI, layered MWW, and layered FER molecular sieves.

5. The method for rapidly controlling the interlayer spacing of layered molecular sieves according to any one of claims 1 to 3, characterized in that: The carrier gas has a flow rate of 20–50 mL / min and is nitrogen. The carrier gas carries vaporized intercalation reagent through a reactor containing layered molecular sieves for 1–6 hours, and the carrier gas carries vaporized deionized water through a reactor containing layered molecular sieves for 1–6 hours.

6. The method for rapidly controlling the interlayer spacing of layered molecular sieves according to any one of claims 1 to 3, characterized in that: The intercalation reagent and deionized water are heated to 40–70 °C for vaporization.

7. The method for rapidly controlling the interlayer spacing of layered molecular sieves according to any one of claims 1 to 3, characterized in that: The layered molecular sieve was heated to 450 ℃ at a heating rate of 8-15 ℃ / min under inert gas protection and held at that temperature for 2 hours. Then, the inert gas was switched to air or oxygen, and the temperature was increased to 550 ℃ at a heating rate of 8-15 ℃ / min and held for 3-4 hours.

8. The use of the pillared molecular sieve obtained by the method according to any one of claims 1 to 3 in the catalytic oxidation of cyclooctene with hydrogen peroxide to prepare cyclooxygenated cyclooctane.

9. The use of the pillared molecular sieve obtained by the method according to claim 8 in the catalytic oxidation of cyclooctene with hydrogen peroxide to prepare cyclooxygenated cyclooctane, characterized in that: The column-supported molecular sieve is ground and pressed into tablets to 40-60 mesh, then mixed with an equal mass of quartz sand and loaded into the catalyst bed of a fixed-bed reactor. Hydrogen peroxide and cyclooctene are simultaneously pumped into the fixed-bed reactor using injection pumps, with the hydrogen peroxide flow rate set at 0.5-5 mL / min and the cyclooctene flow rate at 0.5-10 mL / min, and the reactor temperature set at 50-90 ℃.

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