IWV molecular sieve containing metal heteroatoms as well as preparation method and application of IWV molecular sieve

Abstract

The invention relates to the technical field of molecular sieve synthesis, in particular to an IWV molecular sieve containing metal heteroatoms and a preparation method and application thereof. The preparation method comprises the following steps: mixing an organic structure directing agent, a silicon molecular sieve, a metal compound and water to obtain mixed gel; wherein the organic structure directing agent is a benzimidazole ionic compound, and the metal compound is selected from at least one of a germanium compound, an aluminum compound, a titanium compound and a tin compound; carrying out crystallization treatment on the mixed gel to obtain IWV molecular sieve crystals; and roasting the IWV molecular sieve crystal to obtain the metal heteroatom-containing IWV molecular sieve. The preparation method disclosed by the invention not only has the characteristics of simple preparation process, intuitiveness, easiness in control and high production efficiency, but also effectively solves the problem that various metal heteroatoms except aluminum are difficult to efficiently introduce into the IWV molecular sieve in the prior art, and provides possibility for wide application of the IWV molecular sieve in the catalysis field.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieve synthesis, and in particular to an IWV molecular sieve containing metal heteroatoms and a preparation method and application thereof. Background Art

[0002] Molecular sieves are a type of microporous solid material with long-range ordered pore structure, high specific surface area and high hydrothermal stability, and their performance is particularly outstanding. By introducing metal heteroatoms such as Al, Ge, Ti, and Sn into the molecular sieve framework, it is possible to construct a molecular sieve containing metal heteroatoms with unique acidity. This type of molecular sieve plays a vital role as a catalyst in the fields of petrochemicals, environmental protection, and biomedicine due to its shape selectivity and adjustable acidity.

[0003] In the prior art, IWV molecular sieves are famous for their unique two-dimensional cross-12-membered ring macropore system, which forms a 14-membered ring supercage structure at the intersection of the channels, showing good channel connectivity. This feature enables IWV molecular sieves to exhibit good catalytic performance in the Baeyer-Villiger oxidation reaction of ketones and the alkylation reaction of aromatics. However, in the current preparation technology of IWV molecular sieves, it often relies on costly and complex synthetic organic structure directing agents, such as hydroxy-type dimethyl diphenylphosphine or 1,5-bis(1,2,4,5-tetramethylimidazole)pentane. At the same time, the preparation process also uses amorphous tetraethyl orthosilicate as a silicon source, which requires a complex hydrothermal synthesis method of fully hydrolyzing and driving alcohol. This method not only has cumbersome processes and long crystallization cycles, but also has limitations in the introduction of metal elements. It is difficult to effectively introduce metal elements other than aluminum, which limits the potential for widespread application of IWV molecular sieves in the field of catalysis. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an IWV molecular sieve containing metal heteroatoms, a preparation method thereof, and an application thereof. The present invention directly uses silicon molecular sieves and metal compounds to construct IWV molecular sieve crystals with the help of the precise guiding effect of an organic structure directing agent, shortens the crystallization induction period, and reduces the energy barrier for the formation of IWV molecular sieve crystals. The IWV molecular sieve crystals are calcined to successfully obtain an IWV molecular sieve containing metal heteroatoms. The preparation method of the present invention not only has the characteristics of simple preparation process, intuitive and easy control, and high production efficiency, but also effectively solves the problem in the prior art that it is difficult to efficiently introduce multiple metal heteroatoms other than aluminum into the IWV molecular sieve, and provides the possibility for the wide application of IWV molecular sieves in the field of catalysis.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first object of the present invention is to provide a method for preparing an IWV molecular sieve containing metal heteroatoms, comprising the following steps:

[0007] S1, mixing an organic structure directing agent, a silicon molecular sieve, a metal compound and water to obtain a mixed gel; wherein SiO 2 , metal compound, organic structure directing agent, water molar ratio is 1: 0.1 ~ 1: 0.05 ~ 10: 5 ~ 100; if SiO in silicon molecular sieve 2 If the molar ratio of the metal compound, the organic structure directing agent and water is not within the range of 1:0.1 to 1:0.05 to 10:5 to 100, an amorphous structure will be formed, resulting in failure of successful crystallization. The organic structure directing agent is a benzimidazole ionic compound, and the structure of the benzimidazole ionic compound is:

[0008]

[0009] Wherein, R is selected from hydrogen, methyl, ethyl, nonyl or phenyl, hydroxide ion is the counter anion; and the metal compound is selected from at least one of germanium compounds, aluminum compounds, titanium compounds and tin compounds.

[0010] S2. The mixed gel is crystallized. During the crystallization process, the three-dimensional framework of the silicon molecular sieve is decomposed into a primary structure and a secondary structure. Under the guidance of an organic structure directing agent, the primary structure and the secondary structure construct a new molecular sieve framework with the metal compound to obtain an IWV molecular sieve crystal.

[0011] S3, calcining the IWV molecular sieve crystals. During the calcination process, the organic structure directing agent inside the IWV molecular sieve crystals is oxidized and decomposed to obtain an IWV molecular sieve containing metal heteroatoms.

[0012] Preferably, the benzimidazole ionic compound is selected from hydroxyl-type 2-ethyl-1,3-dimethylbenzimidazole, hydroxyl-type 1,2,3-trimethylbenzimidazole, hydroxyl-type 1,3-dimethyl-2-phenylbenzimidazole or hydroxyl-type 1,3-dimethylbenzimidazole.

[0013] Preferably, the silicon molecular sieve is at least one selected from CHA molecular sieve, MFI molecular sieve, MWW molecular sieve, FAU molecular sieve, BEA molecular sieve and STW molecular sieve.

[0014] Preferably, the germanium compound is selected from at least one of germanium isopropoxide, germanium dioxide, tetramethoxygermanium, germanium fluoride, tetramethylgermanium, tetraethylgermanium or germanium nitrate; the aluminum compound is selected from at least one of aluminum acetate, aluminum acetate, aluminum tert-butoxide, aluminum isopropoxide, hydrated aluminum nitrate or sodium aluminate; the titanium compound is selected from at least one of titanic acid, titanium trichloride, titanium tert-butoxide, potassium fluorotitanate, hexafluorotitanic acid or titanium tetramethoxide; the tin compound is selected from at least one of butylstannoic acid, sodium stannate, tetramethyltin, tin oxalate, tin acetate, tin methoxide, tin tetrachloride, stannous chloride, tin acetate or tetrabutyltin.

[0015] Preferably, the crystallization treatment conditions are: static crystallization at 120° C. to 200° C. for 1 to 10 days, while the crystallization period in the prior art is at least 15 days.

[0016] Preferably, after the crystallization treatment, the mixed gel is subjected to multiple washing and drying treatments to obtain IWV molecular sieve crystals; wherein the solvents for the washing treatment are water and acetone; and the drying temperature is 40°C to 120°C.

[0017] Preferably, the calcination conditions are: calcination at 450°C to 650°C for 4h to 10h.

[0018] Preferably, the mixed gel also includes fluoride, which is selected from at least one of sodium fluoride and hydrogen fluoride; wherein the fluoride can reduce the activation energy of crystallization of the silicon molecular sieve, thereby accelerating the crystallization process; and at the same time, adjust the framework structure and pore size distribution of the silicon molecular sieve.

[0019] Preferably, the organic structure directing agent, silicon molecular sieve, metal compound, fluoride and water are mixed to obtain a mixed gel.

[0020] Preferably, the mixed gel contains ˉ :SiO 2 The molar ratio of F is 0 to 5:1; - :SiO 2 When the molar ratio of fluoride is too low, the effect of fluoride is not obvious enough to fully promote crystallization and adjust the structure; - :SiO 2 When the molar ratio is too high, the structure of the silicon molecular sieve will be destroyed, reducing its stability and performance.

[0021] The second object of the present invention is to provide an IWV molecular sieve containing metal heteroatoms prepared by the above preparation method, wherein the IWV molecular sieve containing metal heteroatoms has a thin-layer plate-like crystal structure.

[0022] The third object of the present invention is to provide the use of the above-mentioned IWV molecular sieve containing metal heteroatoms in the preparation of ketone Baeyer-Villiger oxidation catalysts or aromatic alkylation catalysts.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention provides a method for preparing an IWV molecular sieve containing metal heteroatoms, wherein an organic structure directing agent, a silicon molecular sieve, a metal compound and water are mixed to obtain a mixed gel; wherein the SiO 2 , metal compound, organic structure directing agent, water in a molar ratio of 1:0.1 to 1:0.05 to 10:5 to 100; the mixed gel is crystallized, during the crystallization process, the three-dimensional framework of the silicon molecular sieve is decomposed into a primary structure and a secondary structure, and the primary structure and the secondary structure are guided by the organic structure directing agent to construct a new molecular sieve framework with the metal compound to obtain an IWV molecular sieve crystal; the IWV molecular sieve crystal is calcined, during the calcination process, the organic structure directing agent inside the IWV molecular sieve crystal is oxidized and decomposed to obtain an IWV molecular sieve containing metal heteroatoms. The preparation method of the present invention not only has the characteristics of simple preparation process, intuitive and easy control, and high production efficiency, but also effectively solves the problem in the prior art that it is difficult to efficiently introduce multiple metal heteroatoms other than aluminum into the IWV molecular sieve, which provides the possibility for the wide application of IWV molecular sieve in the field of catalysis.

[0025] Among them, the benzimidazole ion compound used in the present invention not only has the advantages of being cheap and easy to obtain, but also has unique properties due to its semi-rigid structure. It can not only play the role of "cavity filler" and stabilize the structure, but also has a high guiding specificity for the IWV molecular sieve structure, and can guide the silicon molecular sieve and the metal compound to form the IWV molecular sieve crystal during the crystallization process; the silicon molecular sieve provides the silicon element required for constructing the IWV molecular sieve framework, and at the same time, promotes the rapid formation of the IWV molecular sieve crystal structure, greatly reduces the energy barrier for the formation of the IWV molecular sieve crystal, and enables metal ions of different sizes to smoothly enter the molecular sieve framework; the metal compound is introduced into the IWV molecular sieve framework as a heteroatom to improve the catalytic performance of the IWV molecular sieve; water is used as a solvent and reaction medium to promote mixing and reaction between the components.

[0026] 2. The IWV molecular sieve containing metal heteroatoms provided by the present invention has excellent thermal stability, chemical stability and high catalytic activity.

[0027] Among them, compared with the traditional amorphous silicon source, the present invention adopts silicon molecular sieve, which promotes the rapid formation of the crystal structure of the IWV molecular sieve containing metal heteroatoms and ensures its highly ordered arrangement, thereby giving the IWV molecular sieve extremely high crystallinity, and further significantly enhancing the thermal stability and chemical stability of the IWV molecular sieve; the IWV molecular sieve containing metal heteroatoms of the present invention presents a thin layer plate-like crystal morphology, and its skeleton structure can flexibly accommodate and adjust the content of various metals in a large range, which not only improves the pore structure of the IWV molecular sieve containing metal heteroatoms, improves the connectivity between the pores, but also significantly increases the specific surface area, providing more active sites and reaction space for the catalytic reaction, thereby improving the catalytic efficiency; in addition, the introduction of various metals not only enriches the acidic type of the IWV molecular sieve containing metal heteroatoms, but also enhances the diversity and complexity of its catalytic function, providing more possibilities and choices for the catalytic reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the X-ray diffraction spectrum of the IWV silicon-germanium molecular sieve prepared in Example 1 of the present invention.

[0029] Figure 2 This is a scanning electron microscope image of the IWV silicon-germanium-aluminum molecular sieve prepared in Example 3 of the present invention.

[0030] Figure 3 This is a scanning electron microscope image of the IWV silicon titanium molecular sieve prepared in Example 4 of the present invention.

[0031] Figure 4 This is the UV-visible absorption spectrum of the IWV silicon-tin molecular sieve prepared in Example 7 of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the data in the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the prior art, although IWV molecular sieves have attracted attention for their unique pore structure and good catalytic performance, their preparation process faces many challenges. The preparation of IWV molecular sieves not only relies on expensive organic structure directing agents, such as hydroxy-type dimethyldiphenylphosphine or 1,5-bis(1,2,4,5-tetramethylimidazole)pentane, but also uses amorphous tetraethyl orthosilicate as a silicon source, which requires a complex hydrothermal synthesis method of sufficient hydrolysis and alcohol removal. This not only leads to cumbersome processes and long crystallization cycles, but also has significant limitations in the introduction of metal elements, especially the difficulty in effectively introducing metal elements other than aluminum, which greatly restricts the potential for widespread application of IWV molecular sieves in the field of catalysis.

[0034] In view of the problems existing in the prior art, the present invention provides a method for preparing an IWV molecular sieve containing metal heteroatoms, comprising the following steps: mixing an organic structure directing agent, a silicon molecular sieve, a metal compound and water to obtain a mixed gel; wherein the SiO 2 , metal compound, organic structure directing agent, water in a molar ratio of 1:0.1 to 1:0.05 to 10:5 to 100; the organic structure directing agent is a benzimidazole ion compound, and the structure of the benzimidazole ion compound is:

[0035]

[0036] Wherein, R is selected from hydrogen, methyl, ethyl, nonyl or phenyl, and hydroxide ion is a counter anion; the metal compound is selected from at least one of germanium compounds, aluminum compounds, titanium compounds and tin compounds; the mixed gel is crystallized, during which the three-dimensional framework of the silicon molecular sieve is decomposed into a primary structure and a secondary structure, and the primary structure and the secondary structure are guided by an organic structure directing agent to construct a new molecular sieve framework with the metal compound to obtain an IWV molecular sieve crystal; the IWV molecular sieve crystal is calcined, during which the organic structure directing agent inside the molecular sieve crystal is oxidatively decomposed to obtain an IWV molecular sieve containing metal heteroatoms.

[0037] The present invention uses benzimidazole ionic compounds as organic structure directing agents, denoted as OSDA, uses silicon molecular sieves to replace traditional amorphous silicon sources, and uses the precise guiding effect of the organic structure directing agent to directly use silicon molecular sieves to construct IWV molecular sieve crystals, significantly shortening the crystallization induction period, greatly reducing the energy barrier for the formation of IWV molecular sieve crystals, and allowing metal ions of different sizes to smoothly enter the molecular sieve framework. The preparation method of the present invention not only has the characteristics of simple preparation process, intuitive and easy control, and high production efficiency, but also effectively solves the problem of the difficulty in efficiently introducing multiple metal heteroatoms other than aluminum into IWV molecular sieves in the prior art, and provides the possibility for the wide application of IWV molecular sieves in the field of catalysis.

[0038] The technical solution of the present invention is further explained by using embodiments below, which are specifically as follows:

[0039] Example 1

[0040] A method for preparing an IWV molecular sieve containing metal heteroatoms comprises the following steps:

[0041] S1, weigh 0.48g of hydroxyl type 2-ethyl-1,3-dimethylbenzimidazole, 0.90g of deionized water, 0.10g of germanium dioxide and 0.15g of CHA topological structure, mix them evenly, and stir at room temperature for 2h to obtain a mixed gel; wherein, SiO 2 :GeO 2 :OSDA:H 2 The molar ratio of O is 1:0.40:1:20.

[0042] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 120°C for 4 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 70°C for 10 hours to obtain IWV molecular sieve crystals.

[0043] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 550° C. for 5 h in an air atmosphere to obtain an IWV silicon-germanium molecular sieve.

[0044] Example 2

[0045] A method for preparing an IWV molecular sieve containing metal heteroatoms is the same as the preparation method of Example 1, except that the germanium dioxide in S1 is replaced by aluminum acetate, the CHA molecular sieve is replaced by MWW molecular sieve, and the SiO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.28:3.06:16.67, comprising the following steps:

[0046] S1, weigh 2.94g of hydroxyl-type 2-ethyl-1,3-dimethylbenzimidazole, 1.50g of deionized water, 0.29g of aluminum acetate and 0.30g of MWW molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.28:3.06:16.67.

[0047] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 140°C for 5 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 80°C for 10 hours to obtain IWV molecular sieve crystals.

[0048] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 500° C. for 5 h in an air atmosphere to obtain an IWV silicon-aluminum molecular sieve.

[0049] Example 3

[0050] A method for preparing an IWV molecular sieve containing a metal heteroatom is the same as the preparation method of Example 2, except that the hydroxyl-type 2-ethyl-1,3-dimethylbenzimidazole in S1 is replaced by hydroxyl-type 1,2,3-trimethylbenzimidazole, aluminum acetate is replaced by hydrated aluminum nitrate, germanium isopropoxide is added, the MWW molecular sieve is replaced by the MFI molecular sieve, and the SiO in the mixed gel is replaced by 1,2,3-trimethylbenzimidazole. 2 :AlO 2 :OSDA:H 2 O was replaced by SiO in a molar ratio of 1:0.28:3.06:16.67 2 :GeO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.70:0.30:0.85:30, comprising the following steps:

[0051] S1, weigh 0.76g of hydroxyl type 1,2,3-trimethylbenzimidazole, 2.70g of deionized water, 1.08g of germanium isopropoxide, 0.32g of hydrated aluminum nitrate and 0.30g of MFI molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :GeO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.70:0.30:0.85:30.

[0052] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 160°C for 2 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 120°C for 10 hours to obtain IWV molecular sieve crystals.

[0053] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 450° C. for 6 h in an air atmosphere to obtain an IWV silicon-germanium-aluminum molecular sieve.

[0054] Example 4

[0055] A method for preparing an IWV molecular sieve containing a metal heteroatom is the same as the preparation method of Example 2, except that the hydroxyl-type 2-ethyl-1,3-dimethylbenzimidazole in S1 is replaced by hydroxyl-type 1,2,3-trimethylbenzimidazole, aluminum acetate is replaced by titanium trichloride, and the MWW molecular sieve is replaced by the FAU molecular sieve. 2 :AlO 2 :OSDA:H 2 O is replaced by SiO in a molar ratio of 1:0.28:3.06:16.67 2 :TiO 2 :OSDA:H 2 The molar ratio of O is 1:0.55:8.50:40, comprising the following steps:

[0056] S1, weigh 3.03g of hydroxyl type 1,2,3-trimethylbenzimidazole, 1.44g of deionized water, 0.17g of titanium trichloride and 0.12g of FAU molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :TiO 2 :OSDA:H 2 The molar ratio of O is 1:0.55:8.50:40.

[0057] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 145°C for 5 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 110°C for 10 hours to obtain IWV molecular sieve crystals.

[0058] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 600° C. for 5 h in an air atmosphere to obtain an IWV silicon-titanium molecular sieve.

[0059] Example 5

[0060] A method for preparing an IWV molecular sieve containing a metal heteroatom is the same as the preparation method of Example 1, except that the hydroxyl-type 2-ethyl-1,3-dimethylbenzimidazole in S1 is replaced by hydroxyl-type 1,3-dimethyl-2-phenylbenzimidazole, germanium dioxide is replaced by tin tetrachloride, CHA molecular sieve is replaced by STW molecular sieve, sodium fluoride is added, and SiO in the mixed gel is 2 :GeO 2 :OSDA:H 2 O is replaced by SiO in a molar ratio of 1:0.40:1:20 2 :SnO 2 :OSDA:F - :H 2The molar ratio of O is 1:0.75:5.75:0.25:60, comprising the following steps:

[0061] S1, weigh 1.38g of hydroxyl type 1,3-dimethyl-2-phenylbenzimidazole, 1.08g of deionized water, 0.26g of tin tetrachloride, 0.01g of sodium fluoride and 0.06g of STW molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :SnO 2 :OSDA:F - :H 2 The molar ratio of O is 1:0.75:5.75:0.25:60.

[0062] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 170°C for 3 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 50°C for 10 hours to obtain IWV molecular sieve crystals.

[0063] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 650° C. for 4 h in an air atmosphere to obtain an IWV silicon-tin molecular sieve.

[0064] Example 6

[0065] A method for preparing an IWV molecular sieve containing a metal heteroatom is the same as the preparation method of Example 2, except that the hydroxyl-type 2-ethyl-1,3-dimethylbenzimidazole in S1 is replaced by hydroxyl-type 1,3-dimethylbenzimidazole, aluminum acetate is replaced by titanium tert-butoxide, and the MWW molecular sieve is replaced by BEA molecular sieve. 2 :AlO 2 :OSDA:H 2 O is replaced by SiO in a molar ratio of 1:0.28:3.06:16.67 2 :TiO 2 :OSDA:H 2 The molar ratio of O is 1:0.25:8.13:100, comprising the following steps:

[0066] S1, weigh 2.67g of hydroxyl type 1,3-dimethylbenzimidazole, 3.60g of deionized water, 0.17g of titanium tert-butylate and 0.12g of BEA molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :TiO 2 :OSDA:H 2 The molar ratio of O is 1:0.25:8.13:100.

[0067] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 150°C for 10 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 100°C for 10 hours to obtain IWV molecular sieve crystals.

[0068] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 575° C. for 6 h in an air atmosphere to obtain an IWV silicon-titanium molecular sieve.

[0069] Example 7

[0070] A method for preparing an IWV molecular sieve containing metal heteroatoms is the same as the preparation method of Example 5, except that the tin tetrachloride in S1 is replaced by tin acetate, the STW molecular sieve is replaced by FAU molecular sieve, and the SiO 2 :SnO 2 :OSDA:F - :H 2 O is replaced by SiO in a molar ratio of 1:0.75:5.75:0.25:60 2 :SnO 2 :OSDA:H 2 The molar ratio of O is 1:0.83:2.50:33.33, comprising the following steps:

[0071] S1, weigh 2.00g of hydroxyl type 1,3-dimethyl-2-phenylbenzimidazole, 2.00g of deionized water, 0.65g of tin acetate and 0.20g of FAU molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :SnO 2 :OSDA:H 2 The molar ratio of O is 1:0.83:2.50:33.33.

[0072] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 170°C for 1 day, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 90°C for 10 hours to obtain IWV molecular sieve crystals.

[0073] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 650° C. for 10 h in an air atmosphere to obtain an IWV silicon-tin molecular sieve.

[0074] Example 8

[0075] A method for preparing an IWV molecular sieve containing a metal heteroatom is the same as the preparation method of Example 1, except that the hydroxyl-type 2-ethyl-1,3-dimethylbenzimidazole in S1 is replaced by hydroxyl-type 1,3-dimethyl-2-nonylbenzimidazole, germanium dioxide is replaced by aluminum isopropoxide, CHA molecular sieve is replaced by MFI molecular sieve, and SiO in the mixed gel is replaced by 1,3-dimethyl-2-nonylbenzimidazole. 2 :GeO 2 :OSDA:H 2 O is replaced by SiO in a molar ratio of 1:0.40:1:20 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.70:3.60:35, comprising the following steps:

[0076] S1, weigh 2.61g of hydroxyl type 1,3-dimethyl-, 2-nonylbenzimidazole, 1.58g of deionized water, 0.36g of aluminum isopropoxide and 0.15g of MFI molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.70:3.60:35.

[0077] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 140°C for 5 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 80°C for 10 hours to obtain IWV molecular sieve crystals.

[0078] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 500° C. for 6 h in an air atmosphere to obtain an IWV silicon-aluminum molecular sieve.

[0079] Example 9

[0080] A method for preparing an IWV molecular sieve containing a metal heteroatom is the same as the preparation method of Example 3, except that the germanium isopropoxide in S1 is replaced by germanium dioxide, the hydrated aluminum nitrate is replaced by aluminum isopropoxide, the MFI molecular sieve is replaced by STW molecular sieve, and the SiO 2 :GeO 2 :AlO 2 :OSDA:H 2 O is replaced by SiO in a molar ratio of 1:0.70:0.30:0.85:30 2 :GeO 2 :AlO 2 :OSDA:H 2The molar ratio of O is 1:0.80:0.10:0.25:15, comprising the following steps:

[0081] S1, weigh 0.45g of hydroxyl type 1,2,3-trimethylbenzimidazole, 2.70g of deionized water, 0.84g of germanium dioxide, 0.20g of aluminum isopropoxide and 0.60g of STW molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :GeO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.80:0.10:0.25:15.

[0082] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 160°C for 7 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 60°C for 10 hours to obtain IWV molecular sieve crystals.

[0083] S3. Place the IWV molecular sieve crystal in a muffle furnace and calcine at 525° C. for 6 h in an air atmosphere to obtain an IWV silicon-germanium-aluminum molecular sieve.

[0084] Comparative Example 1

[0085] A method for preparing an IWV molecular sieve containing metal heteroatoms is the same as the preparation method of Example 4, except that the titanium trichloride in S1 is replaced by germanium dioxide, the FAU molecular sieve is replaced by MWW molecular sieve, and the SiO 2 :TiO 2 :OSDA:H 2 O is replaced by SiO in a molar ratio of 1:0.55:8.50:40 2 :GeO 2 :OSDA:H 2 The molar ratio of O is 1:1.50:2.50:5, comprising the following steps:

[0086] S1, weigh 2.23g of hydroxyl type 1,2,3-trimethylbenzimidazole, 0.45g of deionized water, 0.78g of germanium dioxide and 0.30g of MWW molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :GeO 2 :OSDA:H 2 The molar ratio of O is 1:1.50:2.50:5.

[0087] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 145°C for 5 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 110°C for 10 hours to obtain IWV molecular sieve crystals.

[0088] S3. The IWV molecular sieve crystals were placed in a muffle furnace and calcined at 600°C for 5 h in an air atmosphere to obtain the MWW molecular sieve without crystal structure transformation.

[0089] Comparative Example 2

[0090] A method for preparing an IWV molecular sieve containing metal heteroatoms is the same as the preparation method of Example 6, except that the titanium tert-butoxide in S1 is replaced by sodium aluminate, the BEA molecular sieve is replaced by CHA molecular sieve, and the SiO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.90:20:45, comprising the following steps:

[0091] S1, weigh 6.57g of hydroxyl type 1,3-dimethylbenzimidazole, 1.62g of deionized water, 0.15g of sodium aluminate and 0.12g of CHA molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.90:20:45.

[0092] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 160°C for 7 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 100°C for 10 hours to obtain IWV molecular sieve crystals.

[0093] S3. The IWV molecular sieve crystals were placed in a muffle furnace and calcined at 575°C for 6 hours in an air atmosphere. The test results showed that the sample was mainly an amorphous phase.

[0094] Comparative Example 3

[0095] A method for preparing an IWV molecular sieve containing metal heteroatoms is the same as the method of Example 9, except that the SiO 2 :GeO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.36:0.50:1.25:200; comprising the following steps:

[0096] S1, weigh 0.22g of hydroxyl type 1,2,3-trimethylbenzimidazole, 3.60g of deionized water, 0.04g of germanium dioxide, 0.10g of aluminum isopropoxide and 0.06g of STW molecular sieve, mix them evenly, and stir at room temperature for 3h to obtain a mixed gel; wherein, SiO 2 :GeO 2 :AlO 2 :OSDA:H 2 The molar ratio of O is 1:0.36:0.50:1.25:200.

[0097] S2. Place the mixed gel into a high-temperature and high-pressure reactor lined with polytetrafluoroethylene. After static crystallization in an oven at 160°C for 7 days, take out the sample, wash it with water and centrifuge it 3 times, wash it with acetone and centrifuge it 3 times, and dry it in an oven at 60°C for 10 hours to obtain a solid powder.

[0098] S3. The solid powder was placed in a muffle furnace and calcined at 525°C for 6 hours in an air atmosphere. The test results showed that the sample was an amorphous phase.

[0099] observe Figure 1 It was found that the X-ray diffraction spectrum of the IWV silicon-germanium molecular sieve prepared in Example 1 showed characteristic diffraction peaks at 2θ of 6.4°, 7.0°, 8.0°, 9.5°, 18.1°, 21.0°, 22.0°, 23.1°, and 24.6°, which belonged to the IWV molecular sieve, and there were no other impurity peaks and amorphous bulges, proving that a highly crystalline pure phase IWV silicon-germanium molecular sieve was obtained.

[0100] observe Figure 2 The results show that the IWV silicon-germanium-aluminum molecular sieve presents a uniform thin-layer plate-like morphology without amorphous and other morphological crystals, proving that MFI completely transforms the crystals to synthesize the IWV silicon-germanium-aluminum molecular sieve with high crystallinity.

[0101] observe Figure 3 It was concluded that the IWV silicon-titanium molecular sieve prepared in Example 4 only exhibited a single thin-layer plate-like crystal morphology, proving that the FAU molecular sieve was completely transformed into a pure-phase IWV silicon-titanium molecular sieve with high crystallinity.

[0102] observe Figure 4 It was found that the IWV silicon-tin molecular sieve prepared in Example 7 had a strong characteristic ultraviolet absorption peak of tin element in the framework, but no characteristic absorption peak of tin element outside the framework, indicating that sufficient framework metal species were effectively introduced through the molecular sieve crystal transformation strategy.

[0103] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing an IWV molecular sieve containing metal heteroatoms, characterized in that: The following steps are involved: Mixing an organic structure directing agent, a silicon molecular sieve, a metal compound and water to obtain a mixed gel; wherein the molar ratio of SiO2 in the silicon molecular sieve, the metal compound, the organic structure directing agent and water is 1:0.1 to 1:0.05 to 10:5 to 100; The organic structure directing agent is a benzimidazole ionic compound, and the structure of the benzimidazole ionic compound is: Wherein, R is selected from hydrogen, methyl, ethyl, nonyl or phenyl, and hydroxide ion is a counter anion; the metal compound is selected from at least one of germanium compounds, aluminum compounds, titanium compounds and tin compounds; The mixed gel is crystallized. During the crystallization process, the three-dimensional framework of the silicon molecular sieve is decomposed into a primary structure and a secondary structure. The primary structure and the secondary structure are guided by an organic structure directing agent and combined with a metal compound to form a new molecular sieve framework to obtain an IWV molecular sieve crystal. The IWV molecular sieve crystal is subjected to a calcination treatment. During the calcination process, the organic structure directing agent inside the IWV molecular sieve crystal is oxidized and decomposed to obtain the IWV molecular sieve containing metal heteroatoms.

2. The method for preparing an IWV molecular sieve containing metal heteroatoms according to claim 1, characterized in that: The silicon molecular sieve is at least one selected from CHA molecular sieve, MFI molecular sieve, MWW molecular sieve, FAU molecular sieve, BEA molecular sieve and STW molecular sieve.

3. The method for preparing an IWV molecular sieve containing metal heteroatoms according to claim 1, characterized in that: The germanium compound is selected from at least one of germanium isopropoxide, germanium dioxide, tetramethoxygermanium, germanium fluoride, tetramethylgermanium, tetraethylgermanium or germanium nitrate; the aluminum compound is selected from at least one of aluminum acetate, aluminum acetate, aluminum tert-butoxide, aluminum isopropoxide, hydrated aluminum nitrate or sodium aluminate; the titanium compound is selected from at least one of titanic acid, titanium trichloride, titanium tert-butoxide, potassium fluorotitanate, hexafluorotitanic acid or titanium tetramethoxide; the tin compound is selected from at least one of butylstannoic acid, sodium stannate, tetramethyltin, tin oxalate, tin acetate, tin methoxide, tin tetrachloride, stannous chloride, tin acetate or tetrabutyltin.

4. The method for preparing an IWV molecular sieve containing metal heteroatoms according to claim 1, characterized in that: The crystallization treatment conditions are: static crystallization at 120° C. to 200° C. for 1 to 10 days.

5. The method for preparing an IWV molecular sieve containing metal heteroatoms according to claim 1, characterized in that: The calcination treatment conditions are: calcination at 450° C. to 650° C. for 4 h to 10 h.

6. The method for preparing an IWV molecular sieve containing metal heteroatoms according to claim 1, characterized in that: The mixed gel also includes fluoride, and the fluoride is selected from at least one of sodium fluoride and hydrogen fluoride.

7. The method for preparing an IWV molecular sieve containing metal heteroatoms according to claim 6, characterized in that: The organic structure directing agent, silicon molecular sieve, metal compound, fluoride and water are mixed to obtain a mixed gel.

8. The method for preparing an IWV molecular sieve containing metal heteroatoms according to claim 7, characterized in that: The mixed gel F ˉ : The molar ratio of SiO2 is 0 to 5:

1.

9. An IWV molecular sieve containing metal heteroatoms obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The IWV molecular sieve containing metal heteroatoms has a thin-layer plate-like crystal structure.

10. Use of the IWV molecular sieve containing metal heteroatoms according to claim 9 in the preparation of ketone Baeyer-Villiger oxidation catalysts or aromatic alkylation catalysts.

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