Composite molecular sieve of MFI configuration molecular sieve and MCM-41 molecular sieve as well as preparation method and application of composite molecular sieve

Abstract

The invention relates to a composite molecular sieve of an MFI configuration molecular sieve and an MCM-41 molecular sieve, a preparation method of the composite molecular sieve and application of the composite molecular sieve in cyclohexanone-oxime gas-phase Beckmann rearrangement reaction. The preparation method of the composite molecular sieve comprises the following steps: providing a first molecular sieve containing a first template agent, and then preparing a second molecular sieve in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve, wherein the first template agent and the second template agent are different in chemical structure, and the first molecular sieve is an MFI configuration molecular sieve, and the second molecular sieve is an MCM-41 molecular sieve. The composite molecular sieve material is stable in structure, the active sites of the first molecular sieve can be retained, the introduction of the mesoporous channel structure is beneficial to improving the diffusion efficiency of reactants and products, the occurrence of polymerization reaction is reduced, and the effect of improving the activity and stability of the cyclohexanone-oxime gas phase Beckmann rearrangement reaction is achieved.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, specifically relating to a composite molecular sieve of MFI configuration molecular sieve and MCM-41 molecular sieve, its manufacturing method and its application in the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime. Background Technology

[0002] Caprolactam is an important organic chemical raw material, mainly used in the synthesis of nylon-6. Nylon-6 is a polymer with unique properties, not only resistant to oil, heat, and chemical corrosion, but also possessing strong wear resistance. It is widely used in the production of various civilian and industrial fibers, as well as plastic components and assemblies for automobiles, ships, electronics, engineering machinery, and daily consumer goods. With the stable development of my country's economy, the demand for nylon-6 from industries such as textiles, automobiles, electronics, and transportation is constantly increasing. In recent years, my country's nylon-6 polymerization plants have maintained a positive expansion trend, leading to a gradual increase in caprolactam consumption and demand. According to statistics, my country's nylon-6 production capacity has exceeded 3.5 million tons per year, and its future development momentum remains very promising.

[0003] The production technologies for caprolactam are mainly divided into cyclohexanone oxime gas-phase rearrangement and liquid-phase rearrangement. Compared to the traditional liquid-phase Beckmann rearrangement reaction of cyclohexanone oxime catalyzed by fuming sulfuric acid, gas-phase rearrangement is a novel caprolactam production technology that can complete the conversion of cyclohexanone oxime to caprolactam under the action of a solid acid catalyst. Compared with liquid-phase rearrangement technology, gas-phase rearrangement technology does not require the use of fuming sulfuric acid, eliminates the process of neutralizing sulfuric acid with liquid ammonia, and does not produce the byproduct ammonium sulfate, greatly reducing the consumption of liquid ammonia in the caprolactam production process and avoiding problems such as equipment corrosion and environmental pollution.

[0004] Since the cyclohexanone oxime gas-phase Beckmann rearrangement reaction typically occurs at temperatures of 300°C and above, the weakly acidic active sites of high-silica or all-silica molecular sieves can effectively catalyze this reaction. However, reactants and products are prone to polymerization and coking under high-temperature conditions. Traditional molecular sieves are mostly microporous with narrow and simple pores, resulting in low molecular diffusion efficiency. This makes it difficult for reactants and products to diffuse, leading to coking within the pores, causing reduced catalytic efficiency and rapid catalyst deactivation. Therefore, improving the diffusion performance of molecular sieve catalysts is crucial for enhancing the performance of the cyclohexanone oxime gas-phase Beckmann rearrangement reaction. Some studies have shown that mesoporous molecular sieves have large pore volumes and specific surface areas, and their pore sizes are uniform and tunable, making them widely used in macromolecular catalysis. However, the amorphous pore wall structure of mesoporous molecular sieves leads to poor hydrothermal stability and low activity. Microporous-mesoporous composite molecular sieves combine the characteristics of microporous molecular sieves and mesoporous molecular sieves. They have the abundant acidic sites and good hydrothermal stability of microporous molecular sieves, as well as the excellent diffusion properties and anti-coking ability of mesoporous materials, making them suitable for application in the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime.

[0005] For example, CN102557064A discloses a method for synthesizing a composite molecular sieve for preparing caprolactam. A solution mixture containing a silicon compound, water, and a structure-directing agent is aged. The resulting aged mixture containing crystals is mixed with another silicon compound, water, and structure-directing agent, and the mixture is subjected to a hydrothermal synthesis reaction to obtain an all-silicon composite molecular sieve catalyst. After alkali treatment, the catalyst is applied to the gas-phase rearrangement reaction of cyclohexanone oxime, achieving a cyclohexanone oxime conversion rate of 99% and a caprolactam selectivity of over 96%.

[0006] CA104556085A discloses a method for synthesizing all-silica micro / mesoporous composite materials. A template agent, an organosilicon source, an inorganic ammonium source, and water are mixed and aged, then mixed uniformly with a solid silicon source and crystallized to obtain a hollow-structured all-silica micro / mesoporous composite molecular sieve. The all-silica micro / mesoporous composite molecular sieve material synthesized by this method, when used in the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime, achieves a conversion rate of cyclohexanone oxime and a selectivity for caprolactam that both exceed 98%.

[0007] However, existing microporous-mesoporous composite molecular sieve materials still have certain limitations. Due to the mutual constraints between the mesoporous and microporous molecular sieve structures, the synthesized materials are prone to phase separation, making it difficult to organically combine microporous zeolite structures with mesoporous molecular sieve structures. Therefore, this invention provides a method for synthesizing composite molecular sieves with a microporous-mesoporous channel structure. By growing another mesoporous molecular sieve material on the surface of the main microporous molecular sieve material, a tight bond between the mesoporous and microporous molecular sieves is achieved while retaining the active sites on the microporous molecular sieve surface. The microporous structure in the microporous-mesoporous composite molecular sieve provides sufficient active sites, while the mesoporous channels enhance intermolecular diffusion performance, thereby improving the activity and selectivity of the cyclohexanone oxime gas-phase Beckmann rearrangement reaction, inhibiting coking deactivation caused by over-reaction, and increasing catalyst lifespan. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention discloses a composite molecular sieve material, which is composed of two molecular sieves with different pore sizes, wherein the first molecular sieve is a microporous molecular sieve and the second molecular sieve is a mesoporous molecular sieve.

[0009] According to a first embodiment of the present invention, a method for manufacturing a composite molecular sieve is provided, comprising the following steps: 1) providing a first molecular sieve containing a first template agent (e.g., manufacturing the first molecular sieve containing the first template agent in the presence of the first template agent), and then 2) manufacturing a second molecular sieve in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve, wherein the first template agent and the second template agent are chemically different, and the first molecular sieve is an MFI configuration molecular sieve (preferably an S-1 molecular sieve), and the second molecular sieve is an MCM-41 molecular sieve (preferably an all-silica MCM-41 molecular sieve).

[0010] According to a second embodiment of the present invention, a composite molecular sieve is provided, comprising a first molecular sieve and a second molecular sieve covering the surface of the first molecular sieve, wherein the first molecular sieve is an MFI configuration molecular sieve (preferably an S-1 molecular sieve), the second molecular sieve is an MCM-41 molecular sieve (preferably an all-silica MCM-41 molecular sieve), and the mass ratio of the first molecular sieve to the second molecular sieve is (25-50):1, preferably (30-50):1.

[0011] According to a third embodiment of the present invention, a gas-phase Beckmann rearrangement catalyst for cyclohexanone oxime is obtained by ion exchange treatment of the composite molecular sieve of the present invention.

[0012] According to a fourth embodiment of the present invention, a method for producing caprolactam is provided, comprising the step of producing caprolactam by subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in the presence of the present invention's gas-phase Beckmann rearrangement catalyst.

[0013] Technical effect

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The composite molecular sieve material disclosed in this invention is composed of two molecular sieves with different pore sizes: a microporous molecular sieve and a mesoporous molecular sieve, respectively. By utilizing the affinity between the second template agent D used in the second molecular sieve and the first template agent R of the first molecular sieve, and the characteristic of the second template agent D to induce the crystallization of the MCM-41 structure into an MFI structure, these two microporous and mesoporous molecular sieves are organically combined. This composite molecular sieve material has a stable structure, retaining the active sites of the first molecular sieve while the introduction of the mesoporous channel structure helps improve the diffusion efficiency of reactants and products, reduces the occurrence of polymerization reactions, and enhances the activity and stability of the cyclohexanone oxime gas-phase Beckmann rearrangement reaction. Attached Figure Description

[0016] Figure 1 This is the XRD pattern of the composite molecular sieve in Example 1 of the present invention.

[0017] Figure 2 This is the XRD pattern of the composite molecular sieve after light grinding in Example 1 of the present invention.

[0018] Figure 3 These are the pore size distribution diagrams of the S-1 molecular sieve and the composite molecular sieve in Example 1 of the present invention.

[0019] Figure 4 The results are TEM characterization results of the composite molecular sieve synthesized in Example 1 of this invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0021] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0022] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0023] In the context of this invention, all numerical values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numerical value.

[0024] In the context of this invention, "substantially" means that deviations that are acceptable or reasonable to those skilled in the art are permitted, such as deviations within ±2%, ±1%, ±0.5%, or ±0.1%.

[0025] In the context of this invention, the XRD spectrum is measured using a D / max-2500 fully automatic rotating target X-ray diffractometer. The experimental conditions are: Cu target, Kα radiation source, operating voltage 40kV, and tube current 80mA.

[0026] In the context of this invention, the method for measuring the composite structure formed by the first molecular sieve and the second molecular sieve is to use a JEM-2100 high-resolution transmission electron microscope from JEOL Corporation of Japan.

[0027] In the context of this invention, the average thickness of the second molecular sieve is measured using a JEM-2100 high-resolution transmission electron microscope from JEOL Corporation of Japan.

[0028] In the context of this invention, the type of the second molecular sieve is determined by XRD analysis of the powder obtained after lightly grinding the composite molecular sieve and sieving it. Specifically, the light grinding is performed by dry grinding using a mortar and pestle. To facilitate the detachment of the second molecular sieve from the surface of the carrier (first molecular sieve), the entire grinding process is conducted under relatively gentle conditions. The ground composite molecular sieve is then sieved through a mesh of 160 or finer, and the resulting powder (with a higher concentration of the second molecular sieve) is subjected to XRD analysis.

[0029] In the context of this invention, the pore size distribution is measured using an ASAP 2460 physical adsorption instrument via N2 adsorption-desorption method. Before measurement, the sample is activated by vacuuming at 300°C for 4 hours, and the pore size distribution is analyzed using a DFT model.

[0030] In the context of this invention, the average particle size is measured according to GB / T 6288-2021 Method for Determination of Particle Size of Granular Molecular Sieve.

[0031] In the context of this invention, the specific surface area, pore volume, and pore size are measured using an ASAP 2460 physical adsorption instrument via N2 adsorption-desorption method. Before measurement, the sample is activated by vacuuming at 300°C for 4 hours. The specific surface area of ​​the sample is calculated using the BET method, the pore volume is calculated using the BJH model, and the pore size distribution is analyzed using the DFT model.

[0032] In the context of this invention, the template agent content is measured by thermogravimetric analysis, and the weight loss at a temperature above 200°C until the weight loss curve stabilizes is taken as the template agent content of the molecular sieve.

[0033] In the context of this invention, the free water content is measured using a halogen moisture analyzer at a test temperature of 120°C for 10 minutes.

[0034] In the context of this invention, the template agent loss rate is measured by thermogravimetric analysis. The weight loss at temperatures above 200°C until the weight loss curve stabilizes is the template agent content. The template agent loss rate is calculated as: (template agent content in the molecular sieve before washing - template agent content in the molecular sieve after washing) / template agent content in the molecular sieve before washing * 100%.

[0035] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight.

[0036] In the context of this invention, any two or more embodiments or aspects of this invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of this invention.

[0037] According to one aspect of the present invention, a method for manufacturing a composite molecular sieve is provided, comprising the following steps:

[0038] 1) Provide a first molecular sieve containing a first template agent (e.g., manufacture the first molecular sieve containing the first template agent in the presence of the first template agent), then

[0039] 2) A second molecular sieve is manufactured in the presence of a second template agent and a first molecular sieve containing a first template agent to obtain the composite molecular sieve.

[0040] According to one aspect of the present invention, the inventors have discovered that the first molecular sieve needs to have abundant active sites to allow the cyclohexanone oxime gas-phase Beckmann rearrangement reaction to occur sufficiently; the second molecular sieve is designed to provide mesoporous channels to enhance the diffusion of reactants and products. Therefore, the first molecular sieve is selected from MFI-configured molecular sieves (preferably S-1 molecular sieves), and the second molecular sieve is an MCM-41 molecular sieve (preferably all-silica MCM-41 molecular sieve).

[0041] According to the present invention, "then" means that step 2) must be performed after step 1). Specifically, the second molecular sieve is manufactured only after the first molecular sieve containing the first template agent is manufactured according to step 1). Therefore, according to the present invention, the first molecular sieve containing the first template agent and the second molecular sieve are not manufactured simultaneously. As a case of simultaneous manufacturing, for example, the first molecular sieve and the second molecular sieve can be manufactured simultaneously in the presence of the first template agent and the second template agent.

[0042] According to one aspect of the invention, in step 1), a silicon source, an aluminum source, an alkali source, and water are also present. The silicon source (calculated as SiO2): the aluminum source (calculated as Al2O3): the alkali source (calculated as OH-) -1 (Calculation): The molar ratio of the first template agent to water is SiO2:Al2O3:OH. - :R:H2O=1:0-0.01:0-2:0.03-1:5-60 (preferably SiO2:Al2O3:OH) - :R:H20=1:0:0-2:0.03-1:5-60).

[0043] According to a specific embodiment of the present invention, in step 2), a silicon source, an aluminum source, an alkali source, and water are also present. The silicon source (calculated as SiO2): the aluminum source (calculated as Al2O3): the alkali source (calculated as OH-) -1 (Calculation): The molar ratio of the second template agent D to water is SiO2:Al2O3:OH. - :D:H2O=1:0-0.01:0.1-0.5:0.02-1:20-200 (preferably SiO2:Al2O3:OH) - :D:H20=1:0:0.1-0.3:0.03-1:20-200).

[0044] According to one aspect of the present invention, the mass ratio of the first molecular sieve containing the first template agent to the silicon source (based on SiO2) in step 2) is (20-50):1, preferably (25-50):1. The inventors of the present invention have discovered that the first molecular sieve needs to provide sufficient active sites for rearrangement reactions, while the second molecular sieve enhances intermolecular diffusion. If the amount of the second molecular sieve is too large, it will reduce the proportion of active sites and affect the framework stability of the composite molecular sieve; if it is too small, it cannot enhance diffusion, leading to side reactions such as polymerization.

[0045] According to one aspect of the present invention, the average particle size of the first molecular sieve containing the first template agent is 85% or more passing through 60 mesh, preferably 90% or more passing through 100 mesh. The inventors of the present invention have discovered that when the molecular sieve particle size is too large, it is detrimental to the growth of the second molecular sieve on its surface.

[0046] According to one aspect of the present invention, the free water content of the first molecular sieve containing the first template agent is no more than 10 wt%, preferably no more than 5 wt%. The inventors of the present invention have found that a lower water content can ensure the particle dispersion of the first molecular sieve. If the water content is too high, it will cause the dispersibility of the first molecular sieve to decrease, resulting in a viscous state, which will affect the growth of the second molecular sieve on its surface.

[0047] According to one aspect of the invention, after the first molecular sieve containing the first template agent is washed twice with deionized water at room temperature, the loss rate of the first template agent is less than 10 wt% (preferably less than 5 wt% or less than 2 wt%). According to the invention, the first template agent is substantially entirely embedded within the pores of the first molecular sieve during its manufacturing process, and the interaction between the agent and the first molecular sieve is not simply physical adsorption or physical mixing; therefore, the washing loss rate is very small.

[0048] According to one aspect of the invention, the first template agent and the second template agent are chemically different. Preferably, the first template agent and the second template agent have similar polarities and can form hydrogen bonds to each other in the presence of water. The inventors of the invention have discovered that the similar polarities of the first and second template agents attract each other, and both template agents contain nitrogen-containing functional groups, which bond to each other through hydrogen bonds. The two bonded template agents self-assemble to form a composite template agent, which, after secondary crystallization, yields micro-mesoporous composite molecular sieve materials with different crystal phases. While "coating" the mesoporous molecular sieve MCM-41 configuration molecular sieve precursor onto the surface of the main MFI configuration molecular sieve, the formed composite template agent enhances the bonding between the mesoporous and microporous molecular sieves, thereby obtaining a structurally stable micro-mesoporous composite molecular sieve.

[0049] According to the present invention, "similar polarity" means that the first template agent and the second template agent have a small difference in molecular polarity. Specifically, if the two template agent molecules contain the same type and similar number of polar functional groups and the polar functional groups are relatively symmetrically positioned in the molecules, especially ammonium groups or substituted ammonium groups, or if the two template agents are mutually soluble or have a small difference in solubility in the same solvent (e.g., less than 20%), then they can be considered to have a small difference in molecular polarity.

[0050] The inventors of this invention have discovered that the first template agent and the second template agent have similar polarities, which attracts them to each other. Furthermore, if both template agents contain nitrogen-containing functional groups, the two template agents can bond with each other after forming hydrogen bonds through the nitrogen-containing functional groups.

[0051] According to one aspect of the invention, the first template agent can be used to synthesize the first molecular sieve. Specifically, the first template agent is selected from at least one of ethylenediamine, triethanolamine, tetrapropylammonium hydroxide, n-butylamine, ethylamine, 1,6-hexanediamine, tripropylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide, preferably tetrapropylammonium hydroxide.

[0052] According to one aspect of the invention, the second template agent can be used to synthesize the second molecular sieve. Specifically, the second template agent is selected from at least one of hexadecyltrimethylammonium bromide, dodecyl primary amine, alkyl dimethylamine and diquaternary ammonium ions, long-chain quaternary ammonium bases or salts, preferably hexadecyltrimethylammonium bromide.

[0053] According to one aspect of the invention, step 1) comprises the following steps:

[0054] 1-1) A first mixture is formed by mixing a silicon source, an aluminum source, an alkali source, a first template agent, and water.

[0055] 1-2) Crystallize the first mixture to generate the first molecular sieve containing the first template agent.

[0056] 1-3) Separate the first molecular sieve containing the first template agent (preferably, optionally after filtration, dry (especially spray dry) the first molecular sieve containing the first template agent).

[0057] According to one aspect of the invention, there is no particular limitation on the silicon source, which can be any silicon source conventionally used in the manufacture of molecular sieves in the art, such as one or more of silica sol, silica fume, water glass and organosilicone esters, preferably tetraethyl orthosilicate.

[0058] According to one aspect of the invention, there is no particular limitation on the aluminum source, which can be any aluminum source conventionally used in the manufacture of molecular sieves in the art, such as one or more of aluminum hydroxide, boehmite, aluminum isopropoxide, aluminum sulfate and aluminum chloride, preferably sodium aluminate.

[0059] According to one aspect of the invention, there is no particular limitation on the alkali source, which can be any alkali source conventionally used in the manufacture of molecular sieves in the art, such as sodium hydroxide or potassium hydroxide, preferably sodium hydroxide.

[0060] According to one aspect of the present invention, in step 1-2), the crystallization conditions include: crystallization pressure from atmospheric pressure to system autogenous pressure, presence or absence of seed crystals, crystallization temperature of 130-220°C (preferably 150-180°C), and crystallization time of 24-96h (preferably 24-72h).

[0061] According to one aspect of the invention, in steps 1-3), the drying conditions include: a drying temperature of 60-120°C (preferably 65-110°C) and a drying time of 5-20 hours (preferably 8-15 hours). Preferably, the spray drying conditions include: a solid content of 35-65%, an inlet air temperature of 150-250°C, an outlet air temperature of 80-150°C, and an air velocity of 300-1500 m / s. 3 / h.

[0062] According to one aspect of the invention, after steps 1-3), the first molecular sieve containing the first template agent is pulverized (e.g., ground) to an average particle size of more than 85% passing through 60 mesh (preferably more than 90% passing through 100 mesh).

[0063] According to a preferred embodiment of the present invention, the first molecular sieve containing the first template agent is substantially not removed after manufacturing. More preferably, the manufacturing method of the present invention does not include a step capable of removing some or all of the first template agent from the first molecular sieve containing the first template agent. The inventors of the present invention have discovered that if the first molecular sieve does not contain a template agent, or if a first molecular sieve without a template agent is added during the synthesis of the second molecular sieve, and both the first and second template agents are added simultaneously, this situation can lead to the second molecular sieve failing to grow effectively on the surface of the first molecular sieve, causing the synthesis of the micro-mesoporous composite molecular sieve to fail. Since calcination can remove the template agent, according to a preferred embodiment of the present invention, step 1) does not include a calcination step.

[0064] According to one aspect of the invention, step 2) comprises the following steps:

[0065] 2-1) A second mixture is formed by mixing a silicon source, an aluminum source, an alkali source, a second template agent, and water.

[0066] 2-2) Mix the first molecular sieve containing the first template agent with the second mixture to obtain a composite mixture.

[0067] 2-3) Optionally, after drying the composite mixture, crystallize the composite mixture to generate the composite molecular sieve.

[0068] 2-4) After optional washing and / or optional filtration, the composite molecular sieve is dried.

[0069] According to one aspect of the invention, in step 2-2), the second mixture is finely coated (e.g., sprayed) onto the first molecular sieve containing the first template agent. Preferably, the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained after the mixing. In other words, the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained under the manufacturing conditions of the second molecular sieve. Therefore, according to the invention, the second molecular sieve is grown in situ on the first molecular sieve containing the first template agent. The inventors of the invention have found that maintaining the morphological integrity of the first molecular sieve is beneficial for effective bonding with the framework structure of the second molecular sieve and also preserves more active sites and reaction sites for rearrangement reactions. If the morphological integrity of the first molecular sieve is severely compromised, the second molecular sieve will be unable to grow on its surface, seriously affecting the synthesis effect of the composite molecular sieve.

[0070] According to one aspect of the invention, in steps 2-3), drying is an optional step, but is preferred. The inventors of the invention have discovered that the drying process allows the second molecular sieve precursor to form a dry gel on the surface of the first molecular sieve, which is more conducive to the subsequent crystallization process where the molecular sieve grows on its surface. The drying conditions include: a drying temperature of 50-120°C, preferably 50-110°C, and a drying time of 0.1h-20h, preferably 0.5h-12h.

[0071] According to one aspect of the present invention, in step 2-3), the composite mixture is dried, and the crystallization conditions include: the crystallization pressure is from atmospheric pressure to the system's autogenous pressure, the mass ratio of dry adhesive powder to water is 1:(0.2-0.7), preferably 1:(0.3-0.5), and the mixture is placed separately in a hydrothermal high-pressure reactor for two-stage crystallization: the first stage crystallization temperature is 80-120℃ (preferably 90-110℃), and the crystallization time is 12-48h (preferably 12-24h); the second stage crystallization temperature is 130-190℃ (preferably 130-170℃), and the crystallization time is 24-72h (preferably 24-48h).

[0072] According to one aspect of the invention, in steps 2-4), the drying conditions include: a drying temperature of 80-120°C (preferably 85-110°C) and a drying time of 5-20 hours (preferably 8-15 hours).

[0073] According to one aspect of the present invention, the manufacturing method further includes a step of calcining the composite molecular sieve after steps 2-4), wherein the calcination conditions include: calcination temperature of 400-650°C (preferably 450-600°C) under an oxygen-containing atmosphere, and calcination time of 4-20 hours (preferably 4-10 hours).

[0074] According to a specific embodiment of the present invention, the composite molecular sieve can be manufactured according to the manufacturing method described in any of the foregoing or subsequent aspects of this specification. The inventors of the present invention have discovered that, based on TEM transmission electron microscopy results, the first molecular sieve has a complete, smooth crystal structure, and at least a portion of its surface is covered by a dense layer of the second molecular sieve.

[0075] In the composite molecular sieve of the present invention, the first molecular sieve has a complete, smooth crystal structure, at least a portion of its surface is covered by a dense layer of the second molecular sieve, and preferably, the second molecular sieve densely covers substantially the entire surface of the first molecular sieve.

[0076] According to one aspect of the present invention, the mass ratio of the first molecular sieve to the second molecular sieve is (25-50):1, preferably (30-50):1. The inventors of the present invention have discovered that the composite molecular sieve formed by the present invention mainly consists of the second molecular sieve growing on the surface of the first molecular sieve. If the amount of the second molecular sieve is too large, it will reduce the proportion of active sites and affect the framework stability of the composite molecular sieve; if it is too small, it cannot enhance diffusion, leading to side reactions such as polymerization.

[0077] According to one aspect of the invention, the average particle size of the first molecular sieve is 85% or more passing through 60 mesh (preferably 90% or more passing through 100 mesh).

[0078] According to the present invention, since the second molecular sieve accounts for a lower proportion in the entire composite molecular sieve, its contribution to the XRD pattern is smaller. Therefore, the XRD pattern of the composite molecular sieve is substantially the same as that of the first molecular sieve. If the relative intensity of the strongest characteristic diffraction peak in the XRD pattern is designated as 100, then vw = very weak (>0 to <10); w = weak (10 to ≤20); m = moderate (>20 to ≤40); s = strong (>40 to ≤60); vs = very strong (>60 to ≤100). Here, "substantially the same" means that the composite molecular sieve is consistent with the first molecular sieve at least on all characteristic diffraction peaks with relative intensities of s to vs (preferably m to vs). In other words, the composite molecular sieve substantially does not show characteristic diffraction peaks with relative intensities of s to vs associated with the second molecular sieve (when the second molecular sieve is measured alone), unless such characteristic diffraction peaks are shared by both the first and second molecular sieves. Based on the surface properties described above in this specification, and without any theoretical limitations, the inventors of this invention believe that the composite molecular sieve of this invention substantially exhibits the characteristics of the first molecular sieve in terms of bulk properties and substantially exhibits the characteristics of the second molecular sieve in terms of surface properties.

[0079] According to the present invention, compared with the micropore size distribution of the first molecular sieve, the composite molecular sieve exhibits two distribution peaks within the micropore size distribution range: micropore size and mesopore size. It shows a small number of mesopore channels, while the number of micropore channels is slightly reduced. Without being limited by any theoretical framework, the inventors of this invention believe that this is because the second molecular sieve, with its smaller pore size, covers a portion of the surface micropore channels of the first molecular sieve after being assembled onto it, thus reducing the number of large-pore channels, albeit by a small margin. This phenomenon also indicates a tight bond between the first and second molecular sieves.

[0080] According to one aspect of the invention, the composite molecular sieve has a bimodal pore distribution. Furthermore, the most probable pore sizes of the composite molecular sieve are 0.45-0.65 nm (preferably about 0.55 nm) and 3-5 nm (preferably 3.5-4.5 nm), respectively, with pores having a most probable pore size of 0.45-0.65 nm accounting for more than 70% (preferably about 80%) of the total pore volume, and a BET specific surface area of ​​350-550 m². 2 / g (preferably 350-500mg) 2 / g), with a pore volume of 0.35-0.55ml / g (preferably 0.35-0.50ml / g).

[0081] According to one aspect of the invention, there is a gas-phase Beckmann rearrangement catalyst for cyclohexanone oxime, obtained by ion exchange treatment of the composite molecular sieve as described above.

[0082] According to one aspect of the present invention, the conditions for the ion exchange treatment (single) include: an ammonium salt solution concentration of 1-2 mol / L, a solid-liquid mass ratio of the composite molecular sieve to the ammonium salt solution of 1:(10-30), a reaction temperature of 60-100°C, and a reaction time of 1-3 hours.

[0083] According to one aspect of the invention, there is a method for producing caprolactam, comprising the step of producing caprolactam by subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in the presence of a cyclohexanone oxime gas-phase Beckmann rearrangement catalyst as described above.

[0084] According to one aspect of the present invention, the conditions for the gas-phase Beckmann rearrangement reaction include: using a cyclohexanone oxime-ethanol solution as the raw material, nitrogen as the carrier gas, a nitrogen flow rate of 30-50 ml / min, a raw material vaporization temperature of 250-350°C, a reaction temperature of 250°C-400°C, and a feed space velocity of 2-5 h⁻¹. -1 .

[0085] According to one aspect of the invention, a molecular sieve precursor is disclosed, comprising a molecular sieve and a template agent. The precursor has an average particle size of at least 85% passing through 60 mesh (preferably at least 90% passing through 100 mesh), and a free water content of no more than 10 wt% (preferably no more than 5 wt%). The template agent is selected from at least one of ethylenediamine, triethanolamine, tetrapropylammonium hydroxide, n-butylamine, ethylamine, 1,6-hexanediamine, tripropylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide, preferably tetrapropylammonium hydroxide. Furthermore, the molecular sieve is an MFI-configured molecular sieve (preferably an S-1 molecular sieve).

[0086] According to one aspect of the invention, after the precursor is washed twice with deionized water at room temperature, the loss rate of the template agent is less than 10 wt% (preferably less than 5 wt% or less than 2 wt%). Furthermore, based on a total weight of 100 wt% of the precursor, the content of the template agent is 20-70 wt% (preferably 30-60 wt%).

[0087] Example

[0088] The present invention will be further described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0089] Example 1

[0090] (1) 312.2 g of tetraethyl orthosilicate was added dropwise to 220.8 g of TPAOH solution (25 wt%), and then 268.4 g of deionized water was added dropwise to the above mixed solution. The mixture was stirred at room temperature to form a homogeneous initial gel mixture. After crystallization at 170 °C for 48 h, the crystallized product was spray-dried under the following conditions: solid content 30%, inlet air temperature 140 °C, outlet air temperature 80 °C, and inlet air volume 550 m³ / h. 3 / h, the first molecular sieve N1 is obtained, which is the S-1 molecular sieve.

[0091] The main molecular sieve N1 is not calcined, and its average particle size is more than 95% passing through 100 mesh, free water content is 3wt%, template agent content is 35wt%, and template agent loss rate is less than 5wt%.

[0092] (2) Add 0.4g of sodium hydroxide to 100g of water and stir until homogeneous. Then add 13.6g of tetraethyl orthosilicate and 4.36g of hexadecyltrimethylammonium bromide in sequence and stir at room temperature until a homogeneous gel mixture is formed. Spray the gel mixture onto the molecular sieve prepared in step (1) and dry it at 60℃ for 4h to obtain a composite mixture dry gel. Crystallize the composite mixture dry gel at 90℃ and a water vapor pressure of 1MPa for 24 hours, and then crystallize it at 150℃ and a water vapor pressure of 1MPa for 24 hours. After crystallization, dry it at 110℃ for 8h and calcine it at 550℃ in air for 4 hours to obtain the composite molecular sieve M1 formed by covering S-1 molecular sieve with MCM-41 molecular sieve.

[0093] Figure 1 The XRD results show that the XRD pattern of the composite molecular sieve is basically the same as that of the first molecular sieve. Figure 2 The image shows the small-angle XRD pattern of the composite molecular sieve after light grinding. The characteristic diffraction peak of MCM-41 appears at around 2θ = 2.1, indicating that the second molecular sieve is a short-range ordered MCM-41 molecular sieve.

[0094] Figure 3 The results show the pore size distribution of the composite molecular sieve and the first molecular sieve. It can be seen that the composite molecular sieve has two distribution peaks: micropore size and mesopore size. However, there is a significant difference in the number of pore sizes between the two. Compared with the first molecular sieve, the introduction of the second molecular sieve resulted in a distribution peak of mesopore size, and the proportion of micropore size decreased, but the decrease was small. This indicates that the first molecular sieve and the second molecular sieve are tightly combined in a mutually penetrating manner.

[0095] Figure 4 TEM images revealed that the dual-microporous composite molecular sieve M1 comprises a first molecular sieve (S-1 molecular sieve) and a second molecular sieve (MCM-41 molecular sieve) covering the surface of the first molecular sieve, such as... Figure 3 As shown. According to Figure 4 It can be seen that a dense layer of crystalline material covers the original crystal surface of the first molecular sieve S-1, and a clear boundary between the two can be seen when magnified.

[0096] Measurements showed that the mass ratio of the first to the second molecular sieve in the dual-microporous composite molecular sieve M1 was 45:1. The composite molecular sieve exhibited a bimodal pore distribution, with the most probable pore diameters being 0.55 nm and 3.5 nm, respectively. Pores with a most probable diameter of 0.55 nm accounted for 84% of the total pore volume. The BET specific surface area of ​​the composite molecular sieve was 403 m². 2 / g, pore volume is 0.36ml / g.

[0097] (3) The above-mentioned composite molecular sieve was placed in a 1 mol / L ammonium nitrate solution with a solid-liquid mass ratio of 1:10. Three ion exchanges were performed at 80℃, each lasting 1 h. The ion-exchanged sample was filtered, washed, dried at 110℃ for 8 h, and then calcined in a muffle furnace at 550℃ for 4 h. After pressing into tablets, the resulting 20-40 mesh composite molecular sieve catalyst A1 was obtained. The physicochemical properties and evaluation results are shown in Table 1.

[0098] Example 2

[0099] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that: the first molecular sieve was ZSM-5, the silicon source, aluminum source and template agent were silica sol, sodium aluminate and tetraethylammonium hydroxide, and the catalyst was named A2. The evaluation results of the catalyst are shown in Table 1.

[0100] Example 3

[0101] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that the mass ratio of the first molecular sieve to the second molecular sieve was 25:1, the catalyst was named A3, and the evaluation results of the catalyst are shown in Table 1.

[0102] Example 4

[0103] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that: the average particle size of the main molecular sieve N1 was more than 85% passing through 60 mesh, the catalyst was named A4, and the evaluation results of the catalyst are shown in Table 1.

[0104] Example 5

[0105] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that the free water content of the first molecular sieve of the first template agent was 10 wt%, the catalyst was named A5, and the evaluation results of the catalyst are shown in Table 1.

[0106] Example 6

[0107] The synthesis of composite molecular sieves and the preparation and evaluation of catalysts were the same as in Example 1, except that: ordinary drying was used in the molecular sieve preparation process, the catalyst was named A6, and the evaluation results of the catalyst are shown in Table 1.

[0108] Comparative Example 1

[0109] The S-1 molecular sieve crystallization process is the same as in Example 1. After crystallization, it is dried at 110°C for 8 hours and calcined at 550°C in air for 4 hours. The 20-40 mesh particles obtained after tableting and sieving are the comparative catalysts, numbered B1. Its physicochemical properties and evaluation results are shown in Table 1.

[0110] Comparative Example 2

[0111] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that the mass ratio of the first molecular sieve to the second molecular sieve was 10:1, the catalyst was named B2, and the evaluation results of the catalyst are shown in Table 1.

[0112] Comparative Example 3

[0113] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that the mass ratio of the first molecular sieve to the second molecular sieve was 70:1, the catalyst was named B3, and the evaluation results of the catalyst are shown in Table 1.

[0114] Comparative Example 4

[0115] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst are the same as in Example 1, except that: after the first molecular sieve is prepared, it is calcined and then coated with the already manufactured second molecular sieve. The mass ratio of the first molecular sieve to the second molecular sieve is 45:1. The catalyst is named B3. The evaluation results of the catalyst are shown in Table 1.

[0116] Comparative Example 5

[0117] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 1, except that 0.25g of NaOH was added to destroy the structure of the first molecular sieve when preparing the second molecular sieve. The mass ratio of the first molecular sieve to the second molecular sieve was 45:1. The catalyst was named B5. The evaluation results of the catalyst are shown in Table 1.

[0118] Comparative Example 6

[0119] The synthesis of the composite molecular sieve and the preparation and evaluation of the catalyst were the same as in Example 2, except that: 1,6-hexanediol was used to replace the template agent in the preparation of the first molecular sieve, the mass ratio of the first molecular sieve to the second molecular sieve was 45:1, the catalyst was named B6, and the evaluation results of the catalyst are shown in Table 1.

[0120] The conditions for the gas-phase Beckmann rearrangement of cyclohexanone oxime are as follows: 2g of catalyst particles are used, with a cyclohexanone oxime-ethanol solution (mass ratio 1:9) as the raw material, nitrogen gas is introduced as the carrier gas at a flow rate of 30ml / min, the raw material vaporization temperature is 270℃, the reaction temperature is 350℃, and the feed space velocity is 3h. -1 The reaction time is 24 hours.

[0121] Table 1. Physicochemical properties and evaluation results of the catalyst

[0122] Catalyst number <![CDATA[S BET / m 2 / g ]]> <![CDATA[V total / ml / g ]]> Cyclohexanone oxime conversion rate / % Caprolactam selectivity / % A1 403 0.36 99.4 99.2 A2 456 0.34 88.3 86.4 A3 415 0.37 97.8 97.0 A4 397 0.36 97.1 95.6 A5 394 0.36 97.4 96.2 A6 401 0.36 98.3 97.5 B1 389 0.35 80.2 74.7 B2 457 0.59 68.1 76.4 B3 410 0.36 77.3 77.9 B4 401 0.36 78.9 73.1 B5 354 0.39 61.5 67.3 B6 372 0.34 74.4 70.6

[0123] As can be seen from the results in Table 1, the catalyst of the present invention significantly improves the conversion rate of cyclohexanone oxime and the selectivity of caprolactam in the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime compared with the comparative catalyst, proving that the micro-mesoporous composite molecular sieve of the present invention has higher activity and stability.

Claims

1. A method for manufacturing a composite molecular sieve, comprising the following steps: 1) Provide a first molecular sieve containing a first template agent (e.g., manufacture the first molecular sieve containing the first template agent in the presence of the first template agent), then 2) A second molecular sieve is manufactured in the presence of a second template agent and the first molecular sieve containing the first template agent to obtain the composite molecular sieve. The first template agent and the second template agent are different in chemical structure, and the first molecular sieve is an MFI molecular sieve (preferably an S-1 molecular sieve), and the second molecular sieve is an MCM-41 molecular sieve (preferably an all-silica MCM-41 molecular sieve).

2. The manufacturing method of claim 1, wherein in step 1), a silicon source, an aluminum source, an alkali source, and water are further present, wherein the silicon source (calculated as SiO2): the aluminum source (calculated as Al2O3): the alkali source (calculated as OH-) -1 (Calculated): The molar ratio of the first template agent R to water is SiO2:Al2O3:OH. - :R:H2O=1:0-0.01:0-2:0.03-1:5-60 (preferably SiO2:Al2O3:OH) - :R:H2O=1:0:0-2:0.03-1:5-60), and / or, in step 2), a silicon source, an aluminum source, an alkali source, and water are also present, wherein the silicon source (as SiO2): the aluminum source (as Al2O3): the alkali source (as OH) -1 (Calculated): The molar ratio of the second template agent D to water is SiO2: Al2O3: OH. - :D:H2O=1:0-0.01:0.1-0.5:0.02-1:20-200 (Preferred: SiO2:Al2O3:OH) - The mass ratio of the first molecular sieve containing the first template agent to the silicon source (based on SiO2) in step 2) is (20-50):1 (preferably (25-50):1), and / or, more than 85% of the average particle size of the first molecular sieve containing the first template agent passes through 60 mesh (preferably more than 90% passes through 100 mesh), and / or, the free water content of the first molecular sieve containing the first template agent is not greater than 10 wt% (preferably not greater than 5 wt%), and / or, based on the total weight of the first molecular sieve containing the first template agent being 100 wt%, the content of the first template agent is 20-70 wt% (preferably 30-60 wt%), and / or, after washing the first molecular sieve containing the first template agent twice with deionized water at room temperature, the loss rate of the first template agent is less than 10 wt% (preferably less than 5 wt% or less than 2 wt%).

3. The manufacturing method of claim 1, wherein the first template agent and the second template agent are capable of forming hydrogen bonds or ionic bonds with each other in the presence of water, and / or the first template agent is capable of being used to synthesize the first molecular sieve, and / or the first template agent is selected from at least one of ethylenediamine, triethanolamine, tetrapropylammonium hydroxide, n-butylamine, ethylamine, 1,6-hexanediamine, tripropylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide, preferably tetrapropylammonium hydroxide, and / or the second template agent is capable of being used to synthesize the second molecular sieve, and / or the second template agent is selected from at least one of hexadecyltrimethylammonium bromide, dodecyl primary amine, alkyl dimethylamine and dimer quaternary ammonium ions, long-chain quaternary ammonium bases or salts, preferably hexadecyltrimethylammonium bromide.

4. The manufacturing method of claim 1, wherein step 1) comprises the following steps: 1-1) A first mixture is formed by mixing a silicon source, an aluminum source, an alkali source, a first template agent, and water. 1-2) Crystallize the first mixture to generate the first molecular sieve containing the first template agent. 1-3) Separate the first molecular sieve containing the first template agent (preferably, optionally after filtration, dry (especially spray dry) the first molecular sieve containing the first template agent).

5. The manufacturing method of claim 4, wherein in steps 1-2), the crystallization conditions include: The crystallization pressure is from atmospheric pressure to the system's autogenous pressure, with or without seed crystals; the crystallization temperature is 130-220℃ (preferably 150-180℃); the crystallization time is 24-96h (preferably 24-72h); and / or, in steps 1-3), the drying conditions include: a drying temperature of 60-120℃ (preferably 65-110℃); a drying time of 5-20 hours (preferably 8-15 hours); and / or, in steps 1-3), the spray drying conditions include: a solid content of 35-65%; an inlet air temperature of 150-250℃; an outlet air temperature of 80-150℃; and an air velocity of 300-1500 m / s. 3 / h, and / or, further comprising, after steps 1-3), pulverizing (e.g., grinding) the first molecular sieve containing the first template agent to an average particle size of more than 85% passing through 60 mesh (preferably more than 90% passing through 100 mesh).

6. The manufacturing method of claim 1, excluding the step of removing part or all of the first template agent from the first molecular sieve containing the first template agent, and / or, wherein step 1) does not include a calcination step.

7. The manufacturing method of claim 1, wherein step 2) comprises the following steps: 2-1) A second mixture is formed by mixing a silicon source, an aluminum source, an alkali source, a second template agent, and water. 2-2) The first molecular sieve containing the first template agent is mixed with the second mixture to obtain a composite mixture. 2-3) Optionally, after drying the composite mixture, crystallize the composite mixture to generate the composite molecular sieve. 2-4) After optional washing and / or optional filtration, the composite molecular sieve is dried.

8. The manufacturing method of claim 7, wherein in step 2-2), the second mixture is finely coated (e.g., sprayed) onto the first molecular sieve containing the first template agent, and / or, in step 2-2), the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained after the mixing.

9. The manufacturing method of claim 7, wherein in steps 2-3), the composite mixture is dried, and the crystallization conditions include: The crystallization pressure is from atmospheric pressure to the system's own pressure. The mass ratio of dry adhesive powder to water is 1:(0.2-0.7), preferably 1:(0.3-0.5). The powder and water are placed separately in a hydrothermal high-pressure reactor and crystallization is carried out in two stages: the first stage crystallization temperature is 80-120℃ (preferably 90-110℃), and the crystallization time is 12-48h (preferably 12-24h); the second stage crystallization temperature is 130-190℃ (preferably 130-170℃). The crystallization time is 24-72h (preferably 24-48h), and / or the drying conditions include: drying temperature 50-120℃ (preferably 50-110℃), drying time 0.1-20h (preferably 0.5-12h), and / or, in steps 2-4), the drying conditions include: drying temperature 80-120℃ (preferably 85-110℃), drying time 5-20h (preferably 8-15h).

10. The manufacturing method of claim 7, further comprising, after steps 2-4), a step of calcining the composite molecular sieve, wherein the calcination conditions include: Under an oxygen-containing atmosphere, the calcination temperature is 400-650℃ (preferably 450-600℃), and the calcination time is 4-20 hours (preferably 4-10 hours).

11. The manufacturing method of claim 1, wherein in step 1), the first molecular sieve containing the first template agent is substantially not removed after manufacturing, and / or, in step 2), the morphological integrity (particularly the bulk structure or pore structure) of the first molecular sieve containing the first template agent is substantially maintained under the manufacturing conditions of the second molecular sieve, and / or, in step 2), the second molecular sieve is grown in situ on the first molecular sieve containing the first template agent.

12. A composite molecular sieve, comprising a first molecular sieve and a second molecular sieve covering the surface of the first molecular sieve, wherein the first molecular sieve is an MFI configuration molecular sieve (preferably an S-1 molecular sieve), the second molecular sieve is an MCM-41 molecular sieve (preferably an all-silica MCM-41 molecular sieve), and the mass ratio of the first molecular sieve to the second molecular sieve is (25-50):1, preferably (30-50):

1.

13. The composite molecular sieve of claim 12, wherein the average particle size of the first molecular sieve is more than 85% passing through 60 mesh (preferably more than 90% passing through 100 mesh).

14. The composite molecular sieve of claim 12, wherein the first molecular sieve and the second molecular sieve are substantially interconnected in terms of pores, and / or, the XRD pattern of the composite molecular sieve is substantially the same as that of the first molecular sieve, and / or, the composite molecular sieve has a bimodal pore distribution, and / or, the most probable pore sizes of the pore distribution of the composite molecular sieve are 0.45-0.65 nm (preferably about 0.55 nm) and 3-5 nm (preferably 3.5-4.5 nm), respectively, and / or, the pores with the most probable pore size of 0.45-0.65 nm account for more than 70% (preferably about 80%) of the total pore volume of the composite molecular sieve, and / or, the BET specific surface area of ​​the composite molecular sieve is 350-550 m². 2 / g (preferably 350-500mg) 2 / g), with a pore volume of 0.35-0.55ml / g (preferably 0.35-0.50ml / g).

15. The composite molecular sieve of claim 12 can be manufactured according to the manufacturing method of any one of claims 1-11.

16. A gas-phase Beckmann rearrangement catalyst for cyclohexanone oxime, obtained by ion exchange treatment of the composite molecular sieve of claim 12.

17. The catalyst of claim 16, wherein the conditions for the ion exchange treatment (single) include: The concentration of the ammonium salt solution is 1-2 mol / L, the solid-liquid mass ratio of the composite molecular sieve to the ammonium salt solution is 1:(10-30), the reaction temperature is 60-100℃, and the reaction time is 1-3 hours.

18. A method for producing caprolactam, comprising the step of producing caprolactam by subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in the presence of the cyclohexanone oxime gas-phase Beckmann rearrangement catalyst as described in claim 16.

19. The manufacturing method of claim 18, wherein the conditions for the gas-phase Beckmann rearrangement reaction include: Using cyclohexanone oxime-ethanol solution as raw material, nitrogen as carrier gas at a flow rate of 30-50 ml / min, raw material vaporization temperature of 250-350℃, reaction temperature of 250℃-400℃, and feed space velocity of 2-5 h⁻¹ -1 .

Images