Molecular sieve material, method of making and use thereof

Abstract

A molecular sieve material having an MFI structure, characterized in that the molecular sieve material is aggregated from molecular sieve crystallites, has a most probable pore diameter in the range of 50-600 nm by mercury intrusion analysis, and has a macropore volume of > 0.7 mL / g. The molecular sieve material can be prepared by a process comprising subjecting a first silica sol composition comprising a first silica source, a templating agent, and water to a first hydrothermal treatment; introducing a second silica source into the silica sol composition when the first hydrothermal treatment is conducted for 2-12 h to obtain a second silica sol composition; subjecting the second silica sol composition to a second hydrothermal treatment; and separating at least a portion of the solid product from the product of the second hydrothermal treatment.

Description

Technical Field

[0001] This invention relates to inorganic materials and their preparation and application, and more specifically to a molecular sieve material, its preparation method, and its application. Background Technology

[0002] Molecular sieves, due to their unique pore structure and active centers, exhibit high activity and product selectivity in many reactions. The technique of inserting titanium into the molecular sieve framework has opened up new avenues for activating hydrogen peroxide and catalyzing organic matter conversion under mild conditions. In particular, the discovery of TS-1 molecular sieve has laid the foundation for the development of new technologies for many hydrogen peroxide-involved oxidation reactions, such as propylene epoxidation, cyclohexanone ammoniation, phenol hydroxylation, and thioether oxidation.

[0003] Due to the limitation of the ten-membered ring pore size in MFI-type molecular sieves, reaction efficiency and catalytic performance are affected, thus limiting the substrates for their catalytic reactions to organic compounds with relatively small molecular sizes. Existing molecular sieve preparation technologies typically consider expanding the pore size within the molecular sieve crystal (such as alkali treatment and silanization) to optimize mesopore distribution and enhance intracrystalline diffusion, while paying less attention to surface diffusion. For most industrial catalytic reactions using molecular sieves, they usually need to be shaped before use. Common shaping methods include tableting, extrusion molding, ball rolling, oil column molding, and drop ball forming. The binders typically added during shaping may clog the molecular sieve pores or cover the active centers, while also reducing the space between molecular sieve particles, increasing diffusion resistance, and thus reducing catalytic performance. Conversely, without binders and using methods like tableting, the reaction performance will also decrease due to increased surface diffusion resistance and low catalyst utilization.

[0004] As active components, the diffusion space and macropore distribution between molecular sieves have not been fully considered and studied. Therefore, there is still room for optimization of the pore structure and improvement of the catalytic performance of existing molecular sieve materials. Summary of the Invention

[0005] One of the objectives of this invention is to provide a molecular sieve material with special pore distribution characteristics and optimized pore structure.

[0006] The second objective of this invention is to provide a relatively simple method for preparing the molecular sieve material of this invention, which uses readily available raw materials and is easy to operate.

[0007] A third objective of this invention is to provide applications of the molecular sieve material of this invention, which exhibits excellent performance in catalytic applications.

[0008] To achieve one of the objectives of this invention, this invention provides a molecular sieve material with an MFI structure, characterized in that the molecular sieve material is formed by the aggregation of molecular sieve crystals, and its most probable pore size is in the range of 50-600 nm according to mercury porosimetry analysis, and its macropore volume is ≥0.7 mL / g.

[0009] To achieve the second objective of the present invention, the present invention also provides a method for preparing the product comprising the following steps: (1) providing a silica sol composition, wherein the silica sol composition contains a first silicon source, a template agent and water; (2) subjecting the silica sol composition of step (1) to hydrothermal treatment, wherein a second silicon source is introduced into the silica sol composition within 2-12 hours after the start of the hydrothermal treatment, and the hydrothermal treatment is continued; (3) separating at least a portion of the solid product from the product of step (2).

[0010] To achieve the third objective of this invention, this invention further provides the application of the molecular sieve material with MFI structure of this invention, characterized in that the molecular sieve material of this invention or the molecular sieve material with MFI structure prepared by the preparation method of this invention is used to prepare catalysts, catalytic reactions, supports or adsorbents.

[0011] The molecular sieve material with MFI structure provided by this invention has physicochemical characteristics different from those of the prior art; the preparation method provided by this invention is simple, easy to implement, and low in cost, solving the problem that existing molecular sieve products are powdered materials with single molecular sieve crystals and have poor performance after molding; the molecular sieve material with MFI structure provided by this invention has good technical effects when applied to catalytic reactions and adsorption-desorption separation processes. Attached Figure Description

[0012] Figure 1 The UV-Vis spectrum of the titanium-silicon molecular sieve prepared in Comparative Example 1 is shown.

[0013] Figure 2 The image shows a SEM image of the titanium-silicon molecular sieve prepared in Comparative Example 1.

[0014] Figure 3 BET of the titanium-silicon molecular sieve prepared for Comparative Example 1.

[0015] Figure 4 The image shows the XRD pattern of the titanium-silicon molecular sieve prepared in Example 1.

[0016] Figure 5 The image shows the pore distribution of the titanium-silicon molecular sieve prepared in Example 1, as determined by mercury intrusion porosimetry.

[0017] Figure 6 The UV-Vis spectrum of the titanium-silicon molecular sieve prepared in Example 1 is shown.

[0018] Figure 7The image shows a SEM image of the titanium-silicon molecular sieve prepared in Example 1.

[0019] Figure 8 The image shows the BET plot of the titanium-silicon molecular sieve prepared in Example 1.

[0020] Figure 9 The UV-Vis spectrum of the titanium-silicon molecular sieve prepared for Comparative Example 2 is shown.

[0021] Figure 10 The image shows a SEM image of the titanium-silicon molecular sieve prepared in Comparative Example 2.

[0022] Figure 11 TEM image of the titanium-silicon molecular sieve prepared for Comparative Example 2.

[0023] Figure 12 The BET diagram is for the titanium silicon molecules prepared in Comparative Example 2.

[0024] Figure 13 The image shows the BET plot of the titanium-silicon molecular sieve prepared in Example 6.

[0025] Figure 14 This is a TEM image of the titanium-silicon molecular sieve prepared in Example 6.

[0026] Figure 15 The image shows the XRD pattern of the all-silica molecular sieve prepared in Comparative Example 3.

[0027] Figure 16 Mercury intrusion porosimetry (MIRP) pore distribution of the all-silica molecular sieve prepared for Comparative Example 3.

[0028] Figure 17 SEM image of the all-silica molecular sieve prepared in Comparative Example 3.

[0029] Figure 18 The UV-Vis image is of the tin-silicon molecular sieve prepared in Comparative Example 4.

[0030] Figure 19 The image shows the SEM image of the tin-silicon molecular sieve prepared in Comparative Example 4.

[0031] Figure 20 The BET plot is for the tin-silicon molecular sieve prepared in Comparative Example 4.

[0032] Figure 21 The image shows the XRD pattern of the tin-silicon molecular sieve prepared in Example 11.

[0033] Figure 22 The image shows the UV-Vis pattern of the tin-silicon molecular sieve prepared in Example 11.

[0034] Figure 23 The image shows a SEM image of the tin-silicon molecular sieve prepared in Example 11.

[0035] Figure 24The image shows the BET curve of the tin-silicon molecular sieve prepared in Example 11.

[0036] Figure 25 The image shows a TEM image of the tin-silicon molecular sieve prepared in Example 11.

[0037] Figure 26 The image shows the UV-Vis pattern of the zirconium-silicon molecular sieve prepared in Comparative Example 5.

[0038] Figure 27 The image shows a SEM image of the zirconium-silicon molecular sieve prepared in Comparative Example 5.

[0039] Figure 28 The image shows the BET plot of the zirconium-silicon molecular sieve prepared in Comparative Example 5.

[0040] Figure 29 The image shows the XRD pattern of the zirconium-silicon molecular sieve prepared in Example 12.

[0041] Figure 30 The image shows the UV-Vis pattern of the zirconium-silicon molecular sieve prepared in Example 12.

[0042] Figure 31 The image shows a SEM image of the zirconium-silicon molecular sieve prepared in Example 12.

[0043] Figure 32 The image shows the BET plot of the zirconium-silicon molecular sieve prepared in Example 12.

[0044] Figure 33 The image shows a TEM image of the zirconium-silicon molecular sieve prepared in Example 12. Detailed Implementation

[0045] This invention provides a molecular sieve material with an MFI structure, characterized in that the molecular sieve material is formed by the aggregation of molecular sieve crystals, and its most probable pore size is in the range of 50-600 nm according to mercury porosimetry analysis, and its macropore volume is ≥0.7 mL / g.

[0046] Characterization by scanning electron microscopy (SEM) revealed that this molecular sieve material is composed of aggregated molecular sieve grains. The molecular sieve grains are interconnected through crystal growth. The size of a single molecular sieve grain is 30-800 nm, preferably 100-500 nm, and more preferably 150-350 nm.

[0047] Mercury porosimetry analysis of the molecular sieve material reveals its macropore distribution (where macropores refer to pore structures with a diameter greater than 50 nm). The material exhibits a most probable pore size distribution within the range of 50-600 nm (the most probable pore size distribution refers to the maximum value point on the pore distribution curve; in the molecular sieve material of this invention, this maximum value point falls within the 50-600 nm range), preferably 100-500 nm, more preferably 150-300 nm, and even more preferably 180-260 nm. The macropore volume within this range is ≥0.7 mL / g, preferably 0.9-2 mL / g, more preferably 1.1-1.8 mL / g, and even more preferably 1.3-1.6 mL / g.

[0048] The molecular sieve material was characterized by XRD to have an MFI structure. The relative crystallinity of the molecular sieve material is greater than 80%, preferably greater than 90%, compared with the conventional MFI type all-silica molecular sieve S-1, indicating that the molecular sieve material has good crystallization performance.

[0049] This molecular sieve material contains silicon as the first framework element, or further contains a second framework element. The second framework element is a trivalent or tetravalent element, for example, it can be one or more selected from C, Ge, Sn, Pb, Ti, Zr, Hf, B, Al, and Ga; preferably, the second framework element is selected from at least one of titanium, zirconium, and tin, and the molar ratio of the second framework element to the first framework element is (0.001-0.1):1, preferably (0.01-0.6):1, and even more preferably (0.015-0.4):1. If it does not contain a second framework element, the molecular sieve material is an all-silicon molecular sieve material; if it contains a second framework element, the molecular sieve is a molecular sieve material containing heteroatoms. The second framework element refers to the element that is connected to the first framework element silicon through an oxygen bridge bond via a four-coordinate bond. If the molecular sieve material does not contain a second framework element, it means that the weight content of the second framework element accounts for less than 0.3% of the weight of the molecular sieve material, preferably less than 0.05%, more preferably less than 0.01%, and the weight content of the second framework element can be detected by XRF method.

[0050] The molecular sieve material provided by the present invention can also be characterized by ultraviolet-visible spectroscopy (UV-Vis) to determine the coordination state of the second framework element. For example, when the second framework element is titanium, the signal peak near 210 nm in the UV-Vis spectrum represents a four-coordinate framework titanium species, and the signal peak near 260 nm represents isolated five- or six-coordinate titanium species. Five- or six-coordinate titanium species are generally considered to be titanium species in which titanium atoms are bonded to framework silicon atoms through Si-O-Ti. Such titanium species also have certain catalytic activity (Chinese Journal of Catalysis 42(2021)2189–2196). The signal peak near 330 nm represents anatase species. In this invention, titanium species at 210 nm and 260 nm are classified as active titanium species, and titanium species near 330 nm are classified as inactive titanium species. When the second framework element is tin, the signal peak near 205 nm in the UV-Vis spectrum represents a framework tin species, and the signal peak near 280 nm represents a non-framework tin species. When the second framework element is zirconium, the signal peak near 200 nm in the UV-Vis spectrum represents a framework zirconium species, and the signal peak near 260-350 nm represents a zirconium oxide species.

[0051] The molecular sieve material provided by this invention, when characterized by UV-Vis analysis of the coordination state of the second framework element, preferably, when the second framework element is titanium, has titanium species near 210 nm and near 260 nm in the UV-Vis spectrum accounting for more than 80% of all titanium species as active titanium species, preferably more than 90%, and more preferably more than 95%; when the second framework element is tin, has tin species near 205 nm in the UV-Vis spectrum accounting for more than 80% of all tin species as active tin species, preferably more than 90%, and more preferably more than 95%; when the second framework element is zirconium, has zirconium species near 200 nm in the UV-Vis spectrum accounting for more than 80% of all zirconium species as active zirconium species, preferably more than 90%, and more preferably more than 95%.

[0052] The molecular sieve material provided by the present invention can be further characterized by low-temperature nitrogen adsorption-desorption. Its nitrogen adsorption-desorption line has a hysteresis loop in the medium pressure region (around p / p0 = 0.5), indicating the presence of a mesoporous structure. Characterization by TEM can reveal that there is at least one hollow structure with a size of 5-200 nm in the molecular sieve crystal. The hollow structure preferably has a size of 10-100 nm, and more preferably a size of 15-60 nm.

[0053] In this invention, the classification of micropores, mesopores, and macropores is based on the classification method recommended by IUPAC (International Union of Pure and Applied Chemistry), namely, micropores are pores with a size of less than 2 nm, pores with a size greater than 2 nm and less than 50 nm are mesopores, and pores with a size greater than 50 nm are macropores.

[0054] The present invention also provides a method for preparing a molecular sieve material with an MFI structure, characterized in that it includes: subjecting a first silica sol composition containing a first silicon source, a template agent and water to a first hydrothermal treatment; while the first hydrothermal treatment is carried out for 2-12 hours, introducing a second silicon source into the silica sol composition to obtain a second silica sol composition; subjecting the second silica sol composition to a second hydrothermal treatment; and separating at least a portion of the solid product from the product of the second hydrothermal treatment.

[0055] In the preparation method of the present invention, the first silicon source provides silicon as the first framework element. Common silicon sources known to those skilled in the art can be used as the first silicon source of the present invention, including one or more of tetraalkoxysilane, silica sol, silica gel, and fumed silica. More specifically, it can be one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, tetrapentyl silicate, tetraphenyl silicate, acidic silica sol, neutral silica sol, alkaline silica sol, sodium-containing silica gel, silica gel with low sodium content, and silica. Preferably, it is one or more of tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, and silica.

[0056] In the preparation method of the present invention, optionally, the silica sol composition may further contain a second framework element, wherein the second framework element is selected from at least one of C, Ge, Sn, Pb, Ti, Zr, Hf, B, Al, and Ga, preferably at least one of Sn, Ti, and Zr, and the molar ratio of the second framework element to the first framework element is preferably (0.001-0.1):1, more preferably (0.01-0.06):1, and more preferably (0.015-0.04):1.

[0057] In the preparation method of the present invention, when the second framework element is Ti, the Ti source can be a common titanium source known to those skilled in the art, such as titanium salts, organometallic salts, etc., for example, it can be tetraalkoxy titanium, titanium tetrachloride, titanium trichloride, titanium sulfate, fluorotitanic acid, titanium dichlorocerocene, titanium nitrate, etc., preferably tetraalkoxy titanium and titanium tetrachloride, more preferably at least one of tetraethyl titanate, tetrapropyl titanate, and tetrabutyl titanate.

[0058] In the preparation method of the present invention, when the second framework element is Zr, the Zr source can be a common zirconium source known to those skilled in the art, such as zirconium salts, organometallic salts, etc., for example, zirconium tetrachloride, zirconium trichloride, zirconium oxychloride, zirconium oxysulfate, zirconium nitrate, zirconium acetate, zirconium tetraalkoxy, etc., preferably zirconium tetraalkoxy, more preferably one or more of zirconium tetraethanol, zirconium tetra-n-propoxide, zirconium tetraisopropoxide, and zirconium tetrabutoxide.

[0059] In the preparation method of the present invention, when the second skeleton element is Sn, the Sn source can be a common tin source known to those skilled in the art, such as tin oxides, salts, or organometallic salts, for example, tin dioxide, stannous oxide, stannous trichloride, stannous tetrachloride, stannous chloride, potassium stannate, sodium stannate, metastannic acid, stannic acid, tetramethyltin, tetraethyltin, tetrapropyltin, tetrabutyltin, etc., preferably one or more of stannous tetrachloride, stannous chloride, stannous trichloride, stannic acid, and metastannic acid.

[0060] In the preparation method of the present invention, the template agent has R1R2R3R4N + OH - The structure, wherein R1, R2, R3, and R4 are each independently a C2-C5 alkyl group, or a C2-C5 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups; preferably, R1, R2, R3, and R4 are each independently a C3-C4 alkyl group, or a C3-C4 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups; more preferably, R1, R2, R3, and R4 are each independently a C3 alkyl group, or a C3 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups. For example, R1, R2, R3, and R4 may each be independently one of n-propyl, isopropyl, chloropropyl, 2,3-dichloropropyl, 1-hydroxypropyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-chloro-3-hydroxypropyl, 2-hydroxy-3-chloropropyl, 2-aminopropyl, and 3-aminopropyl. More specifically, the template agent may be one or more of tetrapropylammonium hydroxide, 3-hydroxypropyltripropylammonium hydroxide, tripropyl-2,3-dichloropropylammonium hydroxide, tripropyl-2-chloro-3-hydroxypropylammonium hydroxide, tripropyl-2-hydroxy-3-chloropropylammonium hydroxide, tripropyl-2-aminopropylammonium hydroxide, and tripropyl-3-aminopropylammonium hydroxide. The template agent is generally used in aqueous solution form, and its active ingredient may exist in the form of hydroxide ions, or in the form of hydroxide ions coexisting with other anions (e.g., fluorine, chloride, bromine, iodine, nitrate, sulfate, phosphate, etc.). The molar percentage of the quaternary ammonium base existing in the form of hydroxide ions in the total quaternary ammonium base may be >5%, preferably >20%, more preferably >50%, more preferably >80%, more preferably >90%, and most preferably >99%.

[0061] In the preparation method of the present invention, before the first hydrothermal treatment, the method further includes aging the silica sol composition at 25-100°C for 1-24 hours, preferably at 40-90°C for 3-15 hours, and more preferably at 60-80°C for 6-12 hours.

[0062] In the preparation method of the present invention, the molar composition of the first silicon source, template agent and water in the first silica sol composition is preferably 1:(0.05-0.5):(10-100), more preferably 1:(0.10-0.3):(15-60), and more preferably 1:(0.15-0.25):(20-40).

[0063] The inventors unexpectedly discovered that adding the second silicon source at a specific time during the preparation of molecular sieve materials is beneficial for the interconnection and growth of molecular sieve crystals into a whole, while forming a macroporous structure. This is beneficial for the formation of the catalyst and the diffusion of substrate molecules during application.

[0064] In the preparation method of the present invention, the second silicon source comprises silane and tetraalkoxysilane.

[0065] The silane has the structure A1A2A3Si-A4-SiA5A6A7, wherein A1, A2, A3, A5, A6, and A7 are each independently a C1-C10 alkoxy or halogen group, and A4 is a C1-C10 alkyl or aryl group. Preferably, A1, A2, A3, A5, A6, and A7 are each independently a C1-C6 alkoxy or halogen group, and A4 is a C1-C5 alkyl group. More preferably, A1, A2, A3, A5, A6, and A7 are each independently a C1-C3 alkoxy or halogen group, and A4 is a C1-C3 alkyl group. The silane mentioned can specifically be one or more of the following: bis(trimethoxysilyl)methane, bis(triethoxysilyl)methane, bis(tripropoxysilyl)methane, bis(trichlorosilyl)methane, bis(diethoxychlorosilyl)methane, bis(ethoxydichlorosilyl)methane, bis(trimethoxysilyl)ethane, bis(triethoxysilyl)ethane, bis(tripropoxysilyl)ethane, bis(trichlorosilyl)ethane, bis(diethoxychlorosilyl)ethane, bis(ethoxydichlorosilyl)ethane, bis(trimethoxysilyl)propane, bis(triethoxysilyl)propane, bis(tripropoxysilyl)propane, bis(trichlorosilyl)propane, bis(diethoxychlorosilyl)propane, and bis(ethoxydichlorosilyl)propane.

[0066] The tetraalkoxysilane is preferably one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, tetrapentyl silicate, and tetraphenyl silicate, and more preferably one or more of tetraethyl silicate and tetrapropyl silicate.

[0067] The molar ratio of silane to tetraalkoxysilane is preferably 1:(0-20), more preferably 1:(1-15), and even more preferably 1:(3-9). The molar ratio of the second silicon source to the first silicon source (based on silicon dioxide) is preferably (0.001-0.1):1, further preferably (0.01-0.5):1, and even more preferably (0.05-0.2):1.

[0068] In the preparation method of the present invention, the first hydrothermal treatment and the second hydrothermal treatment are carried out at 130-200℃ for a total time of 5-168h; preferably, they are carried out at 145-180℃ for a total time of 12-130h; more preferably, they are carried out at 155-175℃ for a total time of 24-96h; and even more preferably, they are carried out at 160-170℃ for a total time of 36-72h.

[0069] In the preparation method of the present invention, the separation is intended to separate the solid from the liquid. Any method that can achieve this purpose can be used, including vacuum filtration, atmospheric pressure filtration, membrane filtration, centrifugation, evaporation, sedimentation, etc.

[0070] The preparation method of the present invention further includes drying and calcining the obtained solid product. The drying can be carried out at room temperature to 200°C, preferably 50-160°C, more preferably 80-140°C, under an inert gas atmosphere or an oxygen-containing gas atmosphere, for a processing time sufficient to ensure that the solid water content (by weight) is less than 30%, preferably less than 10%, more preferably less than 5%, for example, 0.5-24 hours. The calcination can be carried out at 300-800°C, preferably 400-700°C, more preferably 500-600°C, under an inert gas atmosphere or an oxygen-containing gas atmosphere, for a processing time sufficient to ensure that the solid organic matter content (by weight) is less than 5%, preferably less than 1%, more preferably less than 0.1%, for example, 0.5-24 hours.

[0071] In the preparation method of this invention, the solid product can be used directly or further processed, such as catalyst molding, impregnation and loading modification, acid / alkali treatment, or use as seed crystals. This invention is not limited in its application. Optionally, the method further includes mixing the solid product with an organic alkali and water, treating it at 150-200°C for 2-48 hours, preferably at 160-180°C for 6-24 hours, and at least partially separating the solid product, followed by drying and calcination to obtain a molecular sieve material containing mesoporous crystals.

[0072] The organic base has the following properties: R5R6R7R8N. + OH -The structure, wherein R5, R6, R7, and R8 are each independently a C2-C4 alkyl group, or a C2-C4 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups. Preferably, R5, R6, R7, and R8 are each independently a C3 alkyl group, or a C3 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups, for example, n-propyl, isopropyl, chloropropyl, 2,3-dichloropropyl, 1-hydroxypropyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-chloro-3-hydroxypropyl, 2-hydroxy-3-chloropropyl, 2-aminopropyl, 3-aminopropyl, etc. The organic base may specifically be one or more of tetrapropylammonium hydroxide, tripropyl-2,3-dichloropropylammonium hydroxide, tripropyl-2-chloro-3-hydroxypropylammonium hydroxide, tripropyl-2-hydroxy-3-chloropropylammonium hydroxide, tripropyl-2-aminopropylammonium hydroxide, and tripropyl-3-aminopropylammonium hydroxide.

[0073] The solid product is mixed with organic base and water in a weight ratio of 1:(0.01-0.5):(0.5-10), preferably 1:(0.03-0.3):(1-7), and more preferably 1:(0.05-0.2):(2-5).

[0074] The present invention further provides a method for applying the above-mentioned molecular sieve material, that is, using the molecular sieve material of the present invention, or containing the molecular sieve material prepared by the method of the present invention, to prepare catalysts, catalytic reactions, supports or adsorbents.

[0075] The catalyst can be prepared by using the molecular sieve material obtained in this invention as the catalytic active component, utilizing its unique framework elements, or by using it as a support to further load active centers, or by using it with other catalysts, co-catalysts, structural aids, electronic aids, binders, inert supports, etc., through mechanical mixing, kneading molding, tablet molding, extrusion molding, spray molding, ball rolling molding, oil column molding, etc.

[0076] The catalytic reaction described herein can be achieved by directly using the molecular sieve material of the present invention as a catalyst or by further preparing a catalyst for use in the catalytic reaction. The catalytic reaction includes, but is not limited to, oxidation reactions (oxidation / epoxidation of olefins to prepare aldehydes, ketones, acids, epoxides, and vicinal diols; oxidation of alkanes to prepare alcohols, aldehydes, and acids; oxidation of alcohols to prepare ketones and acids; oxidation of aldehydes to prepare acids; oxidation of aromatics to prepare phenols; oxidation of thioethers to prepare sulfoxides and sulfones, etc.), reduction reactions, oxime reactions (ammoniation of aldehydes / ketones to prepare amides and lactams), aldol condensation reactions, substitution / halogenation reactions, elimination reactions, transesterification reactions, dehydration reactions, etherification reactions, esterification reactions, double / triple bond addition reactions, diene addition reactions, Beckmann rearrangement reactions (gas-phase rearrangement of cyclohexanone oxime to prepare caprolactam), hydrogen transfer reactions, MPV reactions, etc.

[0077] The aforementioned application as a carrier can be to use the molecular sieve material of the present invention as a carrier to load other active components.

[0078] The adsorbent can be used as an adsorbent in the adsorption and separation process of hydrocarbons, gases, inorganic substances, etc.

[0079] In the application of the molecular sieve material provided by this invention, the molecular sieve material can be used in powder form or in the form of shaped spheres, strips, cakes, granules, etc., and can be mixed with other catalysts; the application can be carried out in various reactors such as batch reactors, slurry bed reactors, fixed bed reactors, fluidized bed reactors, moving bed reactors, and microchannel reactors; the reaction raw materials and catalysts containing molecular sieve material can be fed at once, intermittently, or continuously, and this invention does not limit the feeding.

[0080] Those skilled in the art will understand that in the application of the molecular sieve material of the present invention, the separation of the product and the catalyst can be achieved in a variety of ways. For example, the product can be separated and the catalyst can be recycled and reused by sedimentation, filtration, centrifugation, evaporation, membrane separation, etc. Alternatively, the catalyst can be shaped and loaded into a fixed-bed reactor, and the catalyst can be recovered after the reaction is completed. Various methods for the separation and recovery of catalysts are involved in the existing literature, and will not be described in detail here.

[0081] The molecular sieve material of this invention is a monolithic material formed by in-situ crystallization of molecular sieves. It has high crystallinity and abundant macropores, allowing it to be directly filled into reactors or used after molding. It exhibits high catalyst strength and good substrate molecule diffusion performance. This molecular sieve material avoids the problems of existing molecular sieves requiring further molding, the difficulty in molding high-silicon and heteroatom molecular sieves, the tendency of binders to clog molecular sieve channels, and the loss of catalytic performance. It is more user-friendly in terms of performance.

[0082] The present invention will be further illustrated by the following examples, but these examples do not limit the scope of the invention.

[0083] In the following embodiments and comparative examples:

[0084] The phase structure and relative crystallinity of the molecular sieve were determined by XRD analysis. The instrument used for characterization was a Philips Panalytical Empyrean X-ray diffractometer. The test conditions were: Cu target, Kα radiation, Ni filter, tube voltage 40 kV, tube current 40 mA, scintillation counter, step size 0.0131°, scan range 5°–35°. The relative crystallinity of the molecular sieve was calculated based on the peak area of ​​the "five-finger peak" within the range of 2θ = 22°–26°.

[0085] The chemical composition and the elemental ratio of heteroatoms to silicon in the molecular sieve were determined by XRF analysis. The instrument used for characterization was a Rigaku Electric Co., Ltd. 3013 X-ray fluorescence spectrometer. The testing conditions were: tungsten target, excitation voltage 40 kV, and excitation current 250 mA. After sample pelleting, fluorescence was emitted under X-ray irradiation. The relationship between the fluorescence wavelength (λ) and the atomic number (Z) of the element was: λ = K(ZS)⁻², where K is a constant. The elemental species could be determined by measuring the fluorescence wavelength. Semi-quantitative analysis was performed by measuring the intensity of characteristic spectral lines of each element using a scintillation counter and a proportional counter.

[0086] The macroporous most probable pore size distribution of the molecular sieve was determined by mercury porosimetry. The analysis was performed using an AutoPore IV 9500 fully automated mercury porosimetry system. Low-pressure analysis ranged from 1.38 to 310 kPa (0.2 to 50 psi), with a pore size distribution ranging from 1000 mm to 3.6 mm in diameter; high-pressure analysis reached 227,527 kPa (33,000 psi), with a pore size distribution ranging to 0.0050 mm. The pore distribution and pore size were calculated using the Washburn equation. The states of secondary framework elements such as titanium, tin, and zirconium in the molecular sieve were analyzed using UV-Vis spectroscopy. Analysis was performed using a JASCO UV-Visible 550 UV spectrophotometer. The testing conditions were sample pelleting, with a wavelength scanning range of 190–800 nm.

[0087] The specific surface area of ​​the molecular sieve was measured by nitrogen low-temperature adsorption-desorption method, and the micropore specific surface area was calculated by BET method; the pore volume and pore distribution were determined according to the method described in RIPP 151-90 in "Analytical Methods for Petrochemical Industry" (published by Science Press in September 1990, first edition) compiled by Yang Cuiding et al.

[0088] The morphology of the molecular sieves was determined by SEM. The instrument used for analysis was a Hitachi S4800 high-resolution cold field emission scanning electron microscope with an accelerating voltage of 20 kV. The grain size range data were obtained by statistically analyzing 10-50 molecular sieve grain sizes.

[0089] The hollow morphology of the molecular sieve was determined using TEM. The instrument used was a Tecnai G2F20S-TWIN transmission electron microscope (TEM) manufactured by FEI. The analytical method involved dispersing the sample in an ethanol solution, placing it on a sample grid, drying it, and then performing the measurements. The accelerating voltage was 200 kV.

[0090] Unless otherwise specified, all raw materials used in the examples and comparative examples are analytical grade reagents.

[0091] The reaction products were analyzed by gas chromatography, and the results were quantified using the external standard method. The chromatographic conditions were as follows: Agilent-6890 chromatograph, HP-5 capillary column, injection volume 0.5 μL, injection port temperature 280℃. Column temperature was held at 100℃ for 2 min, then increased to 250℃ at a rate of 15℃ / min and held for 10 min. An FID detector was used, with a detector temperature of 300℃.

[0092] In this example, the all-silica molecular sieve was evaluated using the gas-phase rearrangement of cyclohexanone oxime to produce caprolactam. The reaction conditions were as follows: cyclohexanone oxime underwent a gas-phase rearrangement reaction to generate caprolactam under the catalysis of the all-silica molecular sieve. Molecular sieve tablets (40-60 mesh) were sieved and 5g were packed into a fixed-bed reactor. Cyclohexanone oxime was mixed with methanol solvent at a molar ratio of 1:20. The cyclohexanone oxime solution was pumped into the fixed-bed reactor at a space velocity of 10 h⁻¹, and the reaction was carried out at 380°C. The product was condensed and then subjected to chromatographic analysis.

[0093] The evaluation indicators are:

[0094] Cyclohexanone oxime conversion rate (%) = (Amount of cyclohexanone oxime in feed per unit time - Amount of cyclohexanone oxime in product per unit time) / Amount of cyclohexanone oxime in feed per unit time × 100%

[0095] Caprolactam selectivity (%) = (Number of moles of caprolactam generated in the product / Number of moles of cyclohexanone oxime consumed in all products) × 100%

[0096] In this embodiment, the titanium-silicon molecular sieve was evaluated using the epoxidation of propylene to produce propylene oxide. The reaction conditions were as follows: liquid propylene and hydrogen peroxide underwent an epoxidation reaction under the catalysis of the titanium-silicon molecular sieve to generate propylene oxide. Molecular sieve tablets were pressed into 40-60 mesh and sieved, with 5g of the mixture being packed into a fixed-bed reactor. Hydrogen peroxide and methanol solvent were mixed and pumped separately into the reactor with liquid propylene, and the methanol:hydrogen peroxide:propylene molar ratio was 5:1:2.5. The feed space velocity was 1 h⁻¹, and the reaction was carried out at 40°C. The products were analyzed by chromatography, and the hydrogen peroxide concentration was determined by sodium thiosulfate titration.

[0097] The evaluation criteria are as follows:

[0098] Hydrogen peroxide conversion rate (%) = (Hydrogen peroxide concentration in raw material - Hydrogen peroxide concentration in product) / Hydrogen peroxide concentration in raw material × 100%

[0099] Propylene oxide selectivity (%) = (Number of moles of propylene produced / Number of moles of propylene consumed in all products) × 100%

[0100] In the examples, tin-silicon molecular sieves were evaluated by reacting 1,3-dihydroxyacetone with methanol to prepare methyl lactate. The reaction conditions were as follows: 0.15 g of tin-silicon molecular sieve, 2 g of 1,3-dihydroxyacetone and 10 mL of methanol were added to a 15 mL sealed glass reaction tube, and the reaction was carried out at 80 °C and autogenous pressure for 9 h. The product was then cooled and the liquid product was taken for chromatographic analysis of the product composition.

[0101] The evaluation criteria are as follows:

[0102] 1,3-Dihydroxyacetone Conversion Rate (%) = (Amount of 1,3-dihydroxyacetone in feedstock - Amount of 1,3-dihydroxyacetone in product) / Amount of 1,3-dihydroxyacetone in feedstock × 100%

[0103] Methyl lactate selectivity (%) = (Number of moles of methyl lactate produced / Number of moles of 1,3-dihydroxyacetone consumed in all products) × 100%

[0104] In this example, the zirconium silicate molecular sieve was prepared by reducing levulinic acid and isopropanol via the MPV reaction and then further esterifying them to prepare γ-valerolactone. The reaction process is illustrated below:

[0105]

[0106] Step (1) is catalyzed by zirconium silicate molecular sieve, and step (2) can occur under non-catalytic conditions (such as heating). The weight ratio of zirconium silicate molecular sieve to levulinic acid is 0.05:1, the molar ratio of levulinic acid to isopropanol is 1:20, the reaction temperature is 80℃, the reaction time is 8h, and the liquid phase product is separated and analyzed by chromatography after the reaction is complete.

[0107] The evaluation criteria are as follows:

[0108] Conversion rate of levulinic acid (%) = (Moles of levulinic acid in the feed - Moles of levulinic acid in the product) / Moles of levulinic acid in the feed × 100%

[0109] γ-Valactone yield (%) = (moles of γ-valactone in the product / moles of levulinic acid in the feed) × 100%

[0110] Comparative Example 1

[0111] This comparative example illustrates the comparison sample, titanium-silicon MFI molecular sieve TS-1-D, and its preparation and characterization.

[0112] A silicon source (tetraethyl silicate), tetrabutyl titanate, tetrapropylammonium hydroxide (25 wt%, hydroxide purity greater than 99.5%) solution, and water were mixed in a molar ratio of 1:0.03:0.15:20 and aged at 80°C for 6 h to obtain a sol. The sol was then crystallized at 170°C for 72 h. Finally, the solid product was obtained by filtration from the slurry, and further dried at 120°C for 6 h and calcined at 550°C for 6 h to obtain the comparative sample TS-1-D.

[0113] XRD, XRF, mercury porosimetry, and UV-Vis analysis were performed on TS-1-D. Figure 1 SEM Figure 2 ) and BET Figure 3 The main results of the analysis are shown in Table 1.

[0114] SEM characterization results clearly show that all molecular sieve crystals exist as individual particles dispersed independently, and no molecular sieve crystals were found to be interconnected to form a whole or to form large pores between molecular sieve crystals.

[0115] BET characterization results show that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0116] The propylene epoxidation reaction of TS-1-D was evaluated, and the results are shown in Table 1.

[0117] Example 1

[0118] This embodiment illustrates the molecular sieve material sample TS-1-1 of the present invention and its preparation and characterization.

[0119] Tetraethyl silicate, tetrabutyl titanate, tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.03:0.15:20 and aged at 80°C for 6 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 170°C for 36 hours. After 6 hours of treatment, a second silicon source, consisting of bis(triethoxysilyl)methane and tetraethyl silicate in a molar ratio of 1:5, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.1:1. Hydrothermal treatment continued. After treatment, the solid product was obtained by filtration from the slurry product, dried at 120°C for 6 hours, and calcined at 550°C for 6 hours to obtain the molecular sieve material sample TS-1-1.

[0120] XRD was performed on TS-1-1. Figure 4 XRF, mercury porosimetry Figure 5 ), UV-Vis Figure 6 SEM Figure 7 ) and BET Figure 8 The main results of the analysis are shown in Table 1.

[0121] SEM characterization results clearly show that all molecular sieve grains are interconnected through aggregation growth to form a whole, and large pores are formed between the molecular sieve grains.

[0122] BET characterization results showed that there was no obvious hysteresis ring in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve. The propylene epoxidation reaction of TS-1-1 was evaluated, and the results are shown in Table 1.

[0123] Example 2

[0124] This embodiment illustrates the molecular sieve material sample TS-1-2 of the present invention and its preparation and characterization.

[0125] Tetraethyl silicate, tetraethyl titanate, tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.03:0.2:30 and aged at 80°C for 6 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 170°C for 48 hours. After 4 hours of treatment, a second silicon source, consisting of bis(trimethoxysilyl)ethane and tetraethyl silicate in a molar ratio of 1:9, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.2:1. Hydrothermal treatment continued. After treatment, the slurry product was filtered to obtain a solid product, which was then dried at 120°C for 6 hours and calcined at 550°C for 6 hours to obtain the molecular sieve material sample TS-1-2.

[0126] XRD, XRF, mercury porosimetry, UV-Vis, SEM and BET analyses were performed on TS-1-2. The main results are shown in Table 1.

[0127] SEM characterization results clearly show that all molecular sieve grains are interconnected through aggregation growth to form a whole, and large pores are formed between the molecular sieve grains.

[0128] BET characterization results showed that there was no obvious hysteresis ring in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve. The propylene epoxidation reaction of TS-1-2 was evaluated, and the results are shown in Table 1.

[0129] Example 3

[0130] This embodiment illustrates the molecular sieve material sample TS-1-3 of the present invention and its preparation and characterization.

[0131] Tetraethyl silicate, tetrapropyl titanate, 3-hydroxypropyltripropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.02:0.25:40 and aged at 60°C for 8 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 160°C for 72 hours. After 5 hours of treatment, a second silicon source, consisting of bis(trichlorosilyl)propane and tetraethyl silicate in a molar ratio of 1:3, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.15:1. Hydrothermal treatment continued. After treatment, the slurry product was filtered to obtain a solid product, which was then dried at 120°C for 6 hours and calcined at 550°C for 6 hours to obtain the molecular sieve material sample TS-1-3.

[0132] XRD, XRF, mercury porosimetry, UV-Vis, SEM and BET analyses were performed on TS-1-3. The main results are shown in Table 1.

[0133] SEM characterization results clearly show that all molecular sieve grains are interconnected through aggregation growth to form a whole, and large pores are formed between the molecular sieve grains.

[0134] BET characterization results showed that there was no obvious hysteresis ring in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve. The propylene epoxidation reaction of TS-1-3 was evaluated, and the results are shown in Table 1.

[0135] Example 4

[0136] This embodiment illustrates the molecular sieve material sample TS-1-4 of the present invention and its preparation and characterization.

[0137] Tetraethyl silicate, tetrabutyl titanate, tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.04:0.15:20 and aged at 80°C for 12 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 170°C for 36 hours. After 4 hours of treatment, a second silicon source, consisting of bis(trimethoxysilyl)propane and tetraethyl silicate in a molar ratio of 1:7, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.05:1. Hydrothermal treatment continued. After treatment, the slurry product was filtered to obtain a solid product, which was then dried at 120°C for 6 hours and calcined at 550°C for 6 hours to obtain the molecular sieve material sample TS-1-4.

[0138] XRD, XRF, mercury porosimetry, UV-Vis, SEM and BET analyses were performed on TS-1-4. The main results are shown in Table 1.

[0139] SEM characterization results clearly show that all molecular sieve grains are interconnected through aggregation growth to form a whole, and large pores are formed between the molecular sieve grains.

[0140] BET characterization results show that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0141] The propylene epoxidation reaction of TS-1-4 was evaluated, and the results are shown in Table 1.

[0142] Example 5

[0143] This embodiment illustrates the molecular sieve material sample TS-1-5 of the present invention and its preparation and characterization.

[0144] Tetraethyl silicate, tetrabutyl titanate, tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.04:0.12:15 and aged at 80°C for 6 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 160°C for 72 hours. After 8 hours of treatment, a second silicon source, consisting of bis(trichlorosilyl)ethane and tetraethyl silicate in a molar ratio of 1:12, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.25:1. Hydrothermal treatment continued. After treatment, the slurry product was filtered to obtain a solid product, which was then dried at 120°C for 6 hours and calcined at 550°C for 6 hours to obtain the molecular sieve material sample TS-1-5.

[0145] XRD, XRF, mercury porosimetry, UV-Vis, SEM and BET analyses were performed on TS-1-5. The main results are shown in Table 1.

[0146] SEM characterization results clearly show that all molecular sieve grains are interconnected through aggregation growth to form a whole, and large pores are formed between the molecular sieve grains.

[0147] BET characterization results show that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0148] The propylene epoxidation reaction of TS-1-5 was evaluated, and the results are shown in Table 1.

[0149] Comparative Example 2

[0150] This comparative example illustrates the hollow titanium-silicon molecular sieve HTS-D, its preparation, and characterization.

[0151] The hollow titanium-silicon molecular sieve HTS was prepared according to the method described in Example 1 of Chinese Patent CN1301599A. The molecular sieve comparison sample HTS-D was obtained by rearranging the TS-1-D molecular sieve of Preparation Example 2.

[0152] HTS-D was subjected to XRD, XRF, mercury porosimetry, and UV-Vis analysis. Figure 9SEM Figure 10 ), TEM Figure 11 ) and BET Figure 12 The main results of the analysis are shown in Table 1.

[0153] SEM characterization results clearly show that all molecular sieve crystals exist as individual particles dispersed independently, and no molecular sieve crystals were found to be interconnected to form a whole or to form large pores between molecular sieve crystals.

[0154] TEM characterization revealed the presence of multiple hollow structures with sizes ranging from 20 to 50 nm within the molecular sieve grains.

[0155] BET characterization results indicate that there is a significant hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0156] The propylene epoxidation reaction of HTS-D was evaluated, and the results are shown in Table 1.

[0157] Example 6

[0158] This embodiment illustrates the molecular sieve material sample HTS-1 of the present invention and its preparation and characterization.

[0159] The TS-1-1 molecular sieve material from Example 1 was mixed with tetrapropylammonium hydroxide and water at a weight ratio of 1:0.1:2 and then placed into a reaction vessel. The mixture was treated at 160°C for 12 hours. The resulting product was separated into solids, dried at 120°C for 6 hours, and calcined at 550°C for 6 hours to obtain the molecular sieve material sample HTS-1.

[0160] HTS-1 was subjected to XRD, XRF, mercury porosimetry, UV-Vis, SEM, and BET. Figure 13 ) and TEM Figure 14 The main results of the analysis are shown in Table 1.

[0161] SEM characterization results clearly show that all molecular sieve grains aggregate and grow together to form a whole, and large pores are formed between the molecular sieve grains. TEM characterization results show that there are multiple hollow structures with sizes ranging from 15-40 nm within the molecular sieve grains. BET characterization results show that there is a significant hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0162] The propylene epoxidation reaction of HTS-1 was evaluated, and the results are shown in Table 1.

[0163] Example 7

[0164] This embodiment illustrates the molecular sieve material sample HTS-2 of the present invention and its preparation and characterization.

[0165] The TS-1-1 molecular sieve material from Example 1 was mixed with 3-hydroxypropyltripropylammonium hydroxide and water at a weight ratio of 1:0.2:3 and then placed into a reaction vessel. The mixture was treated at 170°C for 8 hours. The resulting product was separated into solids, dried at 120°C for 6 hours, and calcined at 550°C for 6 hours to obtain the molecular sieve material sample HTS-2.

[0166] HTS-2 was analyzed by XRD, XRF, mercury porosimetry, UV-Vis, SEM, TEM and BET. The main results are shown in Table 1.

[0167] SEM characterization results clearly show that all molecular sieve grains aggregate and grow together to form a whole, and large pores are formed between the molecular sieve grains. TEM characterization results show that there are multiple hollow structures with sizes ranging from 15-40 nm within the molecular sieve grains. BET characterization results show that there is a significant hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0168] The propylene epoxidation reaction of HTS-2 was evaluated, and the results are shown in Table 1.

[0169] Comparative Example 3

[0170] This comparative example illustrates the comparison of the all-silica MFI molecular sieve S-1-D and its preparation and characterization.

[0171] A silicon source (tetraethyl silicate, calculated as silicon dioxide), a tetrapropylammonium hydroxide solution (25 wt%, hydroxide purity greater than 99.5%), and water were mixed in a molar ratio of 1:0.15:20 and aged at 80°C for 6 h to obtain a sol. The sol was then crystallized at 170°C for 72 h. Finally, the solid product was obtained by filtration from the slurry, and further dried at 120°C for 6 h and calcined at 550°C for 6 h to obtain molecular sieve comparison sample S-1-D.

[0172] XRD of S-1-D Figure 15 ), mercury porosimetry Figure 16 SEM Figure 17 The main results of the BET analysis are shown in Table 1.

[0173] SEM characterization results clearly show that all molecular sieve crystals exist as individual particles dispersed independently, with no evidence of molecular sieve crystals interconnected to form a whole or large pores between the crystals. BET characterization results indicate that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0174] The gas-phase rearrangement reaction of S-1-D with cyclohexanone oxime was evaluated, and the results are shown in Table 1.

[0175] Example 8

[0176] This embodiment illustrates the molecular sieve material sample S-1-1 of the present invention and its preparation and characterization.

[0177] Tetraethyl silicate, tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.15:20 and aged at 80°C for 6 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 170°C for 36 hours. After 6 hours of treatment, a second silicon source, consisting of bis(diethoxychlorosilyl)ethane and tetraethyl silicate in a molar ratio of 1:9, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.15:1. Hydrothermal treatment continued. After treatment, the solid product was obtained by filtration from the slurry, dried at 120°C for 6 hours, and calcined at 550°C for 6 hours to obtain molecular sieve material sample S-1-1.

[0178] XRD, mercury porosimetry, UV-Vis, SEM and BET analyses were performed on S-1-1, and the main results are shown in Table 1.

[0179] SEM characterization results clearly show that all molecular sieve grains aggregate and grow together to form a whole, and large pores are formed between the molecular sieve grains. BET characterization results show that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0180] The gas-phase rearrangement reaction of S-1-1 with cyclohexanone oxime was evaluated, and the results are shown in Table 1.

[0181] Example 9

[0182] This embodiment illustrates the molecular sieve material sample S-1-2 of the present invention and its preparation and characterization.

[0183] Tetraethyl silicate, 2-chloro-3-hydroxypropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.15:20 and aged at 60°C for 12 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 160°C for 72 hours. After 4 hours of treatment, a second silicon source, consisting of bis(triethoxysilyl)methane and tetraethyl silicate in a molar ratio of 1:5, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.1:1. Hydrothermal treatment continued. After treatment, the slurry product was filtered to obtain a solid product, which was then dried at 120°C for 6 hours and calcined at 550°C for 6 hours to obtain molecular sieve material sample S-1-2.

[0184] XRD, mercury porosimetry, UV-Vis, SEM and BET analyses were performed on S-1-2. The main results are shown in Table 1.

[0185] SEM characterization results clearly show that all molecular sieve grains aggregate and grow together to form a whole, and large pores are formed between the molecular sieve grains. BET characterization results show that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0186] The gas-phase rearrangement reaction of S-1-2 with cyclohexanone oxime was evaluated, and the results are shown in Table 1.

[0187] Example 10

[0188] This embodiment illustrates the molecular sieve material sample S-1-3 of the present invention and its preparation and characterization.

[0189] Tetraethyl silicate, tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.15:20 and aged at 80°C for 6 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 170°C for 72 hours. After 5 hours of treatment, a second silicon source, consisting of bis(trichlorosilyl)propane and tetraethyl silicate in a molar ratio of 1:3, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.2:1. Hydrothermal treatment continued. After treatment, the solid product was obtained by filtration from the slurry, dried at 120°C for 6 hours, and calcined at 550°C for 6 hours to obtain molecular sieve material sample S-1-3.

[0190] XRD, mercury porosimetry, UV-Vis, SEM and BET analyses were performed on S-1-3. The main results are shown in Table 1.

[0191] SEM characterization results clearly show that all molecular sieve grains aggregate and grow together to form a whole, and large pores are formed between the molecular sieve grains. BET characterization results show that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0192] The gas-phase rearrangement reaction of S-1-3 with cyclohexanone oxime was evaluated, and the results are shown in Table 1.

[0193] Comparative Example 4

[0194] This comparative example illustrates the comparison sample Sn-MFI-D, a tin-silicon MFI molecular sieve, and its preparation and characterization.

[0195] Tetraethyl silicate, tin source (stannous chloride), tetrapropylammonium hydroxide (25 wt%, hydroxide purity greater than 99.5%) solution, and water were mixed in a molar ratio of 1:0.015:0.2:20 and aged at 60°C for 6 h to obtain a sol. The sol was then crystallized at 170°C for 72 h. Finally, the solid product was obtained by filtration from the slurry, and further dried at 120°C for 6 h and calcined at 550°C for 6 h to obtain the comparative sample Sn-MFI-D.

[0196] XRD, XRF, mercury porosimetry, and UV-Vis analysis were performed on Sn-MFI-D. Figure 18 SEM Figure 19 ) and BET Figure 20 The main results of the analysis are shown in Table 1.

[0197] SEM characterization results clearly show that all molecular sieve crystals exist as individual particles dispersed independently, with no evidence of molecular sieve crystals interconnected to form a whole or large pores between the crystals. BET characterization results indicate that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0198] The synthesis reaction of Sn-MFI-D into methyl lactate was evaluated, and the results are shown in Table 1.

[0199] Example 11

[0200] This embodiment illustrates the Sn-MFI molecular sieve material sample of the present invention and its preparation and characterization.

[0201] Tetraethyl silicate, tin source (stannous chloride), tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.015:0.2:20 and aged at 60°C for 6 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 170°C for 36 hours. After 6 hours of treatment, a second silica source, consisting of bis(triethoxysilyl)methane and tetraethyl silicate in a molar ratio of 1:5, was added to the silica sol composition. The molar ratio of the second silica source to the original first silica source in the silica sol composition was 0.1:1. Hydrothermal treatment continued. After treatment, the slurry product was filtered to obtain a solid product, which was then dried at 120°C for 6 hours and calcined at 550°C for 6 hours to obtain the molecular sieve material sample Sn-MFI-J.

[0202] Sn-MFI-J molecular sieve material was mixed with tetrapropylammonium hydroxide and water at a weight ratio of 1:0.1:2 and then loaded into a reaction vessel. The mixture was treated at 160℃ for 12 h. The resulting product was separated into solids, dried at 120℃ for 6 h, and calcined at 550℃ for 6 h to obtain the molecular sieve material sample Sn-MFI.

[0203] XRD of Sn-MFI Figure 21 XRF, mercury porosimetry, UV-Vis Figure 22 SEM Figure 23 ), BET Figure 24 ) and TEM Figure 25 The main results of the analysis are shown in Table 1.

[0204] SEM characterization results clearly show that all molecular sieve grains aggregate and grow together to form a whole, and large pores are formed between the molecular sieve grains. TEM characterization results show that there are multiple hollow structures with sizes ranging from 15-40 nm within the molecular sieve grains. BET characterization results show that there is a significant hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0205] The synthesis reaction of Sn-MFI into methyl lactate was evaluated, and the results are shown in Table 1.

[0206] Comparative Example 5

[0207] This comparative example illustrates the zirconium-silicon MFI molecular sieve Zr-MFI-D, its preparation, and characterization.

[0208] A solution of silicon source (tetraethyl silicate), zirconium n-propoxide, tetrapropylammonium hydroxide (25 wt%, hydroxide purity greater than 99.5%), and water were mixed in a molar ratio of 1:0.015:0.15:20 and aged at 80°C for 6 h to obtain a sol. The sol was then crystallized at 170°C for 72 h. Finally, the solid product was obtained by filtration from the slurry, and further dried at 120°C for 6 h and calcined at 550°C for 6 h to obtain the comparative sample Zr-MFI-D.

[0209] XRD, XRF, mercury porosimetry, and UV-Vis analysis were performed on Zr-MFI-D. Figure 26 SEM Figure 27 ) and BET Figure 28 The main results of the analysis are shown in Table 1.

[0210] SEM characterization results clearly show that all molecular sieve crystals exist as individual particles dispersed independently, with no evidence of molecular sieve crystals interconnected to form a whole or large pores between the crystals. BET characterization results indicate that there is no obvious hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0211] The acetylacetone MPV reaction of Zr-MFI-D was evaluated, and the results are shown in Table 1.

[0212] Example 12

[0213] This embodiment illustrates the molecular sieve material sample Zr-MFI of the present invention and its preparation and characterization.

[0214] Tetraethyl silicate, zirconium n-propoxide, tetrapropylammonium hydroxide, and water were mixed in a molar ratio of 1:0.015:0.15:20 and aged at 80°C for 6 hours to obtain a silica sol composition. This silica sol composition was then placed in a reactor and hydrothermally treated at 170°C for 36 hours. After 6 hours of treatment, a second silicon source, consisting of bis(triethoxysilyl)methane and tetraethyl silicate in a molar ratio of 1:5, was added to the silica sol composition. The molar ratio of the second silicon source to the original first silicon source in the silica sol composition was 0.1:1. Hydrothermal treatment continued. After treatment, the solid product was obtained by filtration from the slurry, dried at 120°C for 6 hours, and calcined at 550°C for 6 hours to obtain the molecular sieve material sample Zr-MFI-J.

[0215] Zr-MFI-J molecular sieve material was mixed with tetrapropylammonium hydroxide and water at a weight ratio of 1:0.1:2 and then loaded into a reaction vessel. The mixture was treated at 160℃ for 12 h. The resulting product was separated into solids, dried at 120℃ for 6 h, and calcined at 550℃ for 6 h to obtain the molecular sieve material sample Zr-MFI.

[0216] XRD of Zr-MFI Figure 29 XRF, mercury porosimetry, UV-Vis Figure 30 SEM Figure 31 ), BET Figure 32 ) and TEM Figure 33 The main results of the analysis are shown in Table 1.

[0217] SEM characterization results clearly show that all molecular sieve grains aggregate and grow together to form a whole, and large pores are formed between the molecular sieve grains. TEM characterization results show that there are multiple hollow structures with sizes ranging from 15-40 nm within the molecular sieve grains. BET characterization results show that there is a significant hysteresis loop in the medium-pressure region (around p / p0 = 0.5) of the low-temperature nitrogen adsorption-desorption curve of the molecular sieve.

[0218] The MPV reaction of TS-1-1 with acetylacetone was evaluated, and the results are shown in Table 1.

[0219] Table 1

[0220]

[0221] As can be seen from the data of Examples 1-10 and Comparative Examples 1-5, the molecular sieve material provided by the present invention grows by interconnecting molecular sieves to form an integral structure and produces a macroporous distribution. Its catalytic performance is significantly improved compared to molecular sieves synthesized by conventional methods. The method for preparing the molecular sieve material provided by the present invention is simple to operate, easy to implement, and has good application prospects.

[0222] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0223] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0224] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a molecular sieve material with an MFI structure, characterized in that, include: The first silica sol composition containing a first silicon source, a template agent and water is aged at 25-100°C for 1-24 hours and then subjected to a first hydrothermal treatment. When the first hydrothermal treatment is carried out for 2-12 hours, a second silicon source is introduced into the first silica sol composition to obtain a second silica sol composition. The second silica sol composition is subjected to a second hydrothermal treatment; Separate at least a portion of the solid product from the product of the second hydrothermal treatment; The first silicon source provides silicon as the first framework element of the molecular sieve material, selected from one or more of tetraalkoxysilane, silica sol, silica gel, and fumed silica; in the first silica sol composition, the molar composition of the first silicon source, template agent, and water is 1:(0.05-0.5):(10-100); the second silicon source contains silane and tetraalkoxysilane, wherein the structure of the silane is A1A2A3Si-A4-SiA5A6A7, wherein A1, A2, A3, A5, A6, and A7 are each independently a C1-C10 alkoxy or halogen group, and A4 is a C1-C10 alkyl or aryl group; the molar ratio of the second silicon source to the first silicon source is (0.001-0.1):1, and the silicon source is calculated as silica; the first hydrothermal treatment and the second hydrothermal treatment are carried out at 130-200℃ for a total time of 5-168h.

2. The preparation method according to claim 1, characterized in that, The template agent has R1R2R3R4N + OH - The structure, wherein R1, R2, R3, and R4 are each independently a C2-C5 alkyl group, or a C2-C5 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups.

3. The preparation method according to claim 2, characterized in that, R1, R2, R3, and R4 are each independently a C3-C4 alkyl group, or a C3-C4 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups.

4. The preparation method according to claim 2, characterized in that, R1, R2, R3, and R4 are each independently a C3 alkyl group, or a C3 alkyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups.

5. The preparation method according to claim 2, characterized in that, R1, R2, R3, and R4 are each independently one of n-propyl, isopropyl, chloropropyl, 2,3-dichloropropyl, 1-hydroxypropyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-chloro-3-hydroxypropyl, 2-hydroxy-3-chloropropyl, 2-aminopropyl, and 3-aminopropyl.

6. The preparation method according to claim 1, characterized in that, The template agent is one or more of tetrapropylammonium hydroxide, 3-hydroxypropyltripropylammonium hydroxide, tripropyl-2,3-dichloropropylammonium hydroxide, tripropyl-2-chloro-3-hydroxypropylammonium hydroxide, tripropyl-2-hydroxy-3-chloropropylammonium hydroxide, tripropyl-2-aminopropylammonium hydroxide, and tripropyl-3-aminopropylammonium hydroxide.

7. The preparation method according to claim 1, characterized in that, The first silica sol composition further contains a second framework element, which is selected from at least one of C, Ge, Sn, Pb, Ti, Zr, Hf, B, Al, and Ga.

8. The preparation method according to claim 7, characterized in that, The second skeleton element is selected from at least one of Sn, Ti, and Zr.

9. The preparation method according to claim 8, characterized in that, When the second framework element is Ti, the titanium source is selected from one or more of titanium tetraalkoxy, titanium tetrachloride, titanium trichloride, titanium sulfate, titanium nitrate, fluorotitanic acid, ammonium fluorotitanate, and titanium dichlorodecene.

10. The preparation method according to claim 8, characterized in that, When the second framework element is Zr, the zirconium source is selected from one or more of zirconium tetrachloride, zirconium trichloride, zirconium oxychloride, zirconium oxysulfate, zirconium nitrate, zirconium acetate, and zirconium tetraalkoxy.

11. The preparation method according to claim 8, characterized in that, When the second skeleton element is Sn, the tin source is selected from one or more of tin dioxide, stannous oxide, tin trichloride, tin tetrachloride, potassium stannate, sodium stannate, metastannic acid, stannic acid, tetramethyltin, tetraethyltin, tetrapropyltin, and tetrabutyltin.

12. The preparation method according to claim 1, characterized in that, The silane is one or more of the following: bis(trimethoxysilyl)methane, bis(triethoxysilyl)methane, bis(tripropoxysilyl)methane, bis(trichlorosilyl)methane, bis(diethoxychlorosilyl)methane, bis(ethoxydichlorosilyl)methane, bis(trimethoxysilyl)ethane, bis(triethoxysilyl)ethane, bis(tripropoxysilyl)ethane, bis(trichlorosilyl)ethane, bis(diethoxychlorosilyl)ethane, bis(ethoxydichlorosilyl)ethane, bis(trimethoxysilyl)propane, bis(triethoxysilyl)propane, bis(tripropoxysilyl)propane, bis(trichlorosilyl)propane, bis(diethoxychlorosilyl)propane, and bis(ethoxydichlorosilyl)propane.

13. The preparation method according to claim 1, characterized in that, The tetraalkoxysilane is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, tetrapentyl silicate, and tetraphenyl silicate.

14. The preparation method according to claim 1, characterized in that, The molar ratio of silane to tetraalkoxysilane is 1:(0-20).

15. The preparation method according to claim 1, characterized in that, The molar ratio of the silane to tetraalkoxysilane is 1:(1-15).

16. The preparation method according to claim 1, characterized in that, The molar ratio of the silane to tetraalkoxysilane is 1:(3-9).

17. The preparation method according to claim 1, characterized in that, The molar ratio of the second silicon source to the first silicon source is (0.01-0.5):

1.

18. The preparation method according to claim 1, characterized in that, The molar ratio of the second silicon source to the first silicon source is (0.05-0.2):

1.

19. The preparation method according to claim 1, characterized in that, The method also includes the steps of mixing the obtained solid product with an organic base and water, treating it at 150-200°C for 2-48 hours and at least partially separating the solid product, and then drying and calcining it.

20. The preparation method according to claim 19, characterized in that, The organic base has R5R6R7R8N. + OH - The structure, wherein R5, R6, R7, and R8 are each independently a C2-C4 alkyl or alkenyl group, or a C2-C4 alkyl or alkenyl group substituted with halogen, hydroxyl, carbonyl, ether, or amino groups.

21. The preparation method according to claim 19, wherein, The solid product is mixed with organic base and water in a weight ratio of 1:(0.01-0.5):(0.5-10).

22. The molecular sieve material with an MFI structure obtained by the preparation method according to any one of claims 1-21, characterized in that, This molecular sieve material is composed of aggregated molecular sieve crystals. Mercury porosimetry analysis shows that its most probable pore size is in the range of 150-300 nm, and its macropore volume is 1.1-1.8 mL / g.

23. The molecular sieve material according to claim 22, characterized in that, The macropore volume is 1.3-1.6 mL / g.

24. The molecular sieve material according to claim 22, characterized in that, Molecular sieve crystals are interconnected through crystal growth.

25. The molecular sieve material according to claim 22, characterized in that, It contains silicon as the first framework element, or further contains a second framework element, which is a trivalent or tetravalent element.

26. The molecular sieve material according to claim 25, characterized in that, The second framework element is selected from at least one of titanium, zirconium, and tin, and the molar ratio of the second framework element to the first framework element is (0.001-0.1):

1.

27. The molecular sieve material according to claim 25, characterized in that, The molar ratio of the second skeleton element to the first skeleton element is (0.01-0.6):

1.

28. The molecular sieve material according to claim 25, characterized in that, The molar ratio of the second skeleton element to the first skeleton element is (0.015-0.4):

1.

29. The molecular sieve material according to claim 22, characterized in that, The relative crystallinity is greater than 80%.

30. The molecular sieve material according to claim 29, characterized in that, The relative crystallinity is greater than 90%.

31. The molecular sieve material according to claim 22, characterized in that, The molecular sieve crystals, as characterized by SEM, have a size of 30-800 nm.

32. The molecular sieve material according to claim 22, characterized in that, The molecular sieve crystals, as characterized by SEM, have a size of 100-500 nm.

33. The molecular sieve material according to claim 22, characterized in that, The molecular sieve crystals, as characterized by SEM, have a size of 150-350 nm.

34. The molecular sieve material according to claim 22, characterized in that, Its nitrogen adsorption-desorption line exhibits a hysteresis loop in the medium-pressure region, and TEM characterization reveals that the molecular sieve crystal contains at least one hollow structure with a size of 5-200 nm.

35. The use of the molecular sieve material according to claim 22 in the preparation of catalysts, catalytic reactions, supports or adsorbents.

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