Preparation method of UZM-35 molecular sieve

Abstract

The invention provides a preparation method of a UZM-35 molecular sieve, and relates to the technical field of molecular sieves. The preparation method comprises the following steps: mixing sodium hydroxide, potassium hydroxide, a structure-directing agent, water, an amorphous aluminum source, an amorphous silicon source, a USY molecular sieve and an MSE molecular sieve seed crystal, and carrying out hydrothermal crystallization on the obtained mixed solution to obtain a crystallized product; and roasting the crystallized product to obtain the UZM-35 molecular sieve. The USY molecular sieve is introduced to provide a silicon source and an aluminum source, the UZM-35 molecular sieve is prepared by a zeolite crystal transformation method, and a mono-quaternary ammonium salt compound with groups such as dimethyl dipropyl and the like is used as a structure-directing agent, so that the rapid and efficient preparation of the UZM-35 molecular sieve is realized (the crystallization time can be shortened to 96 hours), the addition amount of the seed crystal is obviously reduced (the addition amount of the seed crystal is only 0.5-1.5% of the mass of SiO2), and the yield of the UZM-35 molecular sieve is improved. Therefore, the preparation efficiency is improved, and the preparation cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular sieves, and particularly to a preparation method of UZM-35 molecular sieve. Background Art

[0002] Catalysts are the key factors affecting the catalytic cracking to produce light olefins. Among them, molecular sieves have become the preferred catalysts for the catalytic cracking reaction system due to their unique pore structures, adjustable acidic sites and strong anti-coking ability. Molecular sieve skeletons with ten-membered and twelve-membered ring pores have been proven to be more suitable for the hydrocarbon catalytic cracking to light olefins reaction system. Therefore, MSE topology molecular sieves with both ten-membered and twelve-membered rings have development value and application potential in catalytic cracking.

[0003] The MSE type molecular sieve was first proposed by the American Mobil company in 2000. The characteristic structure of the MSE molecular sieve consists of the following three parts: (1) a twelve-membered ring (12-MR) straight channel along a specific crystal axis in the main pore, with a pore diameter of about 0.65nm×0.70nm; (2) secondary pores three-dimensionally cross the main pore through two independent ten-membered rings (10-MR, pore diameter about 0.51nm×0.55nm) to form a diffusion network; (3) the supercage system (18×12R) is only connected to the secondary pores through 10-MR and cannot be directly entered from the main pore channel, with a size of about 1.2nm×1.8nm. MCM-68 and UZM-35 are typical molecular sieves with MSE topology. The UZM-35 molecular sieve has a three-dimensional pore system, including 12-MR and 10-MR channels, and was first proposed by the American UOP company in 2010. Compared with the MCM-68 molecular sieve, the synthesis conditions of the UZM-35 molecular sieve are milder, and it has a higher silicon-aluminum ratio, showing good hydrothermal stability. Researchers studied the differences in the positions and distributions of Brønsted acidic sites in UZM-35 and MCM-68 molecular sieves through spectroscopic methods combined with catalytic activity evaluation. Through 27 Al MAS NMR and FT-IR spectroscopic analysis, it was found that 61% of the acidic active centers in MCM-68 are located in the 12-MR channel, while this ratio in UZM-35 is only 33%, and the number of acid sites in the 10-MR channel is larger. By calculating the n-hexane / 3-methylpentane ratio, the cracking reaction constraint index value of UZM-35 is lower than that of MCM-68, making UZM-35 show higher butene selectivity in the 1-octene cracking reaction, while MCM-68 is more inclined to produce BTX (benzene, toluene and xylene) products. Although UZM-35 has better performance in catalytic cracking, compared with the industrially mainstream ZSM-5 molecular sieve, its industrialization process still faces key restrictive bottlenecks.

[0004] The classical hydrothermal synthesis method of UZM-35 molecular sieve was developed by Mobil Corporation, mainly based on a structure-directing agent to promote the crystallization process without adding seeds. The key steps are as follows: Using N,N,N',N'-tetraethyl-exo,exo-bicyclo[2.2.2]oct-7-ene-2,3,5,6-bistetrahydropyrrolediium diiodide (TEBOP 2+ (I - )2) as the structure-directing agent, combining with a silica-alumina source (such as silica sol, sodium aluminate) and an inorganic base to form a gel. However, the synthesis cost of TEBOP 2+ (I - )2 is high, the synthesis cycle is relatively long, and the crystallization time required for preparing UZM-35 molecular sieve with this structure-directing agent is long (>14 days), which limits the preparation efficiency of MSE molecular sieve and increases the preparation cost. Introducing seeds into the molecular sieve synthesis system, that is, the seed-induced method, can shorten the synthesis cycle to a certain extent. However, currently, the addition amount of seeds is large. Usually, more than 3% of the mass of the silicon source (calculated as SiO2), and even up to 15%, is required to play its corresponding role, which increases the synthesis cost of the molecular sieve. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a preparation method of UZM-35 molecular sieve. The preparation method of UZM-35 molecular sieve provided by the present invention can shorten the crystallization time, reduce the preparation cost, and the addition amount of seeds is small.

[0006] To achieve the above invention purpose, the present invention provides the following technical solutions: The present invention provides a preparation method of UZM-35 molecular sieve, comprising the following steps: Mix sodium hydroxide, potassium hydroxide, a structure-directing agent, water, an amorphous aluminum source, an amorphous silicon source, USY molecular sieve and MSE molecular sieve seeds to obtain a mixed solution; the structure-directing agent is at least one of the monoquaternary ammonium salt compounds of the following groups: diethyldimethyl, dimethyldipropyl, dimethyldiallylethyl, dimethyldiallyl, dimethyldiallylbutyl, diethyldiallylethyl, diethyldiallyl, diethyldiallylbutyl; the amorphous aluminum source is converted to Al(OH)3, the amorphous silicon source is converted to SiO2, the USY molecular sieve is converted to Al(OH)3 and SiO2, and the molar ratio of the effective components in the mixed solution is SiO2:Al(OH)3:structure-directing agent:sodium hydroxide:potassium hydroxide:water = 1:0.067:(0.45~0.60):(0.025~0.10):(0.10~0.20):(15~40), and the mass of MSE molecular sieve seeds is 0.5~1.5% of the mass of SiO2; Perform hydrothermal crystallization on the mixed solution to obtain a crystallization product; The crystallized product is calcined to obtain the UZM-35 molecular sieve.

[0007] Preferably, the monoquaternary ammonium salt compound is ammonium hydroxide or ammonium halide compound of the group.

[0008] Preferably, the amorphous aluminum source is one or more of aluminum sulfate, aluminum hydroxide, and sodium metaaluminate.

[0009] Preferably, the amorphous silicon source is one or more of sodium silicate, silica sol, and white carbon black.

[0010] Preferably, the silica-alumina ratio of the USY molecular sieve is 15 - 30, and the silica-alumina ratio is the molar ratio of silicon element to aluminum element.

[0011] Preferably, the MSE molecular sieve seed is MCM-68 molecular sieve or UZM-35 molecular sieve.

[0012] Preferably, the mass of the MSE molecular sieve seed is 1% of the mass of SiO2.

[0013] Preferably, the method of mixing is as follows: Sodium hydroxide, potassium hydroxide, the structure-directing agent and water are first mixed to obtain a first mixed solution; The first mixed solution is secondarily mixed with the amorphous aluminum source to obtain a second mixed solution; The second mixed solution is tertiarily mixed with the amorphous silicon source to obtain a third mixed solution; The third mixed solution is quaternarily mixed with the USY molecular sieve to obtain a fourth mixed solution; The fourth mixed solution is quinternarily mixed with the MSE molecular sieve seed to obtain the mixed solution.

[0014] Preferably, the temperature of the hydrothermal crystallization is 150 - 200 °C, and the time is 96 - 168 h.

[0015] Preferably, the temperature of the calcination is 500 - 800 °C, and the time is 6 - 12 h.

[0016] The present invention provides a preparation method of UZM-35 molecular sieve. Compared with the prior art, it has the following beneficial effects: The present invention prepares UZM-35 molecular sieve by the zeolite conversion method, introducing USY molecular sieve to provide silicon source and aluminum source, and supplementing with monoquaternary ammonium salt compounds of diethyldimethyl, dimethyldipropyl, dimethyldiallylethyl, dimethyldiallyl, dimethyldiallylbutyl, diethyldiallylethyl, diethyldiallyl, diethyldiallylbutyl as structure-directing agents, which can realize the rapid and efficient preparation of UZM-35 molecular sieve (the crystallization time can be shortened to 96 h), and can significantly reduce the addition amount of seed crystals. The addition amount of seed crystals is only 0.5-1.5% of the mass of SiO2, thereby improving the preparation efficiency, reducing the preparation cost, and facilitating the batch production of UZM-35 molecular sieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 XRD spectrum of the UZM-35 molecular sieve prepared in Example 1; Figure 2 XRD spectrum of the UZM-35 molecular sieve prepared in Example 2; Figure 3 XRD spectrum of the UZM-35 molecular sieve prepared in Example 3; Figure 4 XRD spectrum of the UZM-35 molecular sieve prepared in Example 4; Figure 5 XRD spectra of the UZM-35 molecular sieves prepared in Example 1 and Comparative Example 1; Figure 6 SEM images of the UZM-35 molecular sieves prepared in Example 1 and Comparative Example 1, Figure 6 Among them, (a) is the SEM image of the UZM-35 molecular sieve obtained by the zeolite conversion method in Example 1, and (b) is the SEM image of the UZM-35 molecular sieve obtained by the seed-induced method in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention provides a preparation method of UZM-35 molecular sieve, which includes the following steps: Mix sodium hydroxide, potassium hydroxide, a structure-directing agent, water, an amorphous aluminum source, an amorphous silicon source, USY zeolite, and MSE zeolite seeds to obtain a mixed solution; the structure-directing agent is at least one of the monoquaternary ammonium salt compounds of the following groups: diethyldimethyl, dimethyldipropyl, dimethyldiethylenyl, dimethyldiallyl, dimethyldibutenyl, diethyldiethylenyl, diethyldiallyl, diethyldibutenyl; the amorphous aluminum source is converted to Al(OH)3, the amorphous silicon source is converted to SiO2, the USY zeolite is converted to Al(OH)3 and SiO2, and the molar ratio of the active components in the mixed solution is SiO2:Al(OH)3:structure-directing agent:sodium hydroxide:potassium hydroxide:water = 1:0.067:(0.45 - 0.60):(0.025 - 0.10):(0.10 - 0.20):(15 - 40), and the mass of the MSE zeolite seeds is 0.5 - 1.5% of the mass of SiO2; Perform hydrothermal crystallization on the mixed solution to obtain a crystallized product; Calcine the crystallized product to obtain the UZM-35 zeolite.

[0019] In the present invention, unless otherwise specified, the raw materials involved are well-known commercially available products in the art.

[0020] In the present invention, sodium hydroxide (NaOH), potassium hydroxide (KOH), a structure-directing agent, water, an amorphous aluminum source, an amorphous silicon source, USY zeolite, and MSE zeolite seeds are mixed to obtain a mixed solution.

[0021] In the present invention, the sodium hydroxide and potassium hydroxide provide an alkaline synthesis system. In the present invention, two alkali sources, sodium hydroxide and potassium hydroxide, are added to utilize the unique properties of potassium ions and sodium ions and their synergistic effect to control the synthesis process and optimize the structure and properties of the product; among them, K + tends to stabilize the zeolite structure with larger cavities or windows, and Na + is more suitable for medium-sized pores and cages. Since the UZM-35 zeolite has both 10-membered rings and 12-membered rings, K and Na co-doping is required. In the present invention, the water is preferably deionized water.

[0022] In the present invention, the structure-directing agent is at least one of the monoquaternary ammonium salt compounds of the following groups: diethyldimethyl, dimethyldipropyl, dimethyldivinylethyl, dimethyldiallyl, dimethyldivinylbutyl, diethyldivinylethyl, diethyldiallyl, diethyldivinylbutyl; the monoquaternary ammonium salt compound is preferably the ammonium hydroxide or ammonium halide compound of the group; when the monoquaternary ammonium salt compound is the ammonium hydroxide compound of the group, the monoquaternary ammonium salt compound is specifically: diethyldimethylammonium hydroxide, dimethyldipropylammonium hydroxide, dimethyldivinylethylammonium hydroxide, dimethyldiallylammonium hydroxide, dimethyldivinylbutylammonium hydroxide, diethyldivinylethylammonium hydroxide, diethyldiallylammonium hydroxide, diethyldivinylbutylammonium hydroxide, when the monoquaternary ammonium salt compound is the ammonium halide compound of the group, the monoquaternary ammonium salt compound is specifically: diethyldimethylammonium halide, dimethyldipropylammonium halide, dimethyldivinylethylammonium halide, dimethyldiallylammonium halide, dimethyldivinylbutylammonium halide, diethyldivinylethylammonium halide, diethyldiallylammonium halide, diethyldivinylbutylammonium halide, and the halogen element in the diethyldimethylammonium halide, dimethyldipropylammonium halide, dimethyldivinylethylammonium halide, dimethyldiallylammonium halide, dimethyldivinylbutylammonium halide, diethyldivinylethylammonium halide, diethyldiallylammonium halide and diethyldivinylbutylammonium halide is preferably chlorine or bromine.

[0023] In the present invention, the amorphous aluminum source is preferably one or more of aluminum sulfate, aluminum hydroxide (Al(OH)3) and sodium metaaluminate; the amorphous silicon source is preferably one or more of sodium silicate, silica sol and fumed silica; the silica-alumina ratio of the USY molecular sieve is preferably 15-30, and the silica-alumina ratio is the molar ratio of silicon element to aluminum element (i.e., Si / Al). In the present invention, the USY molecular sieve is introduced to prepare the UZM-35 molecular sieve by the zeolite conversion method. In the actual batching process, the USY molecular sieve is used as the main silicon source and aluminum source, so that the addition amounts of the amorphous aluminum sources such as aluminum sulfate, aluminum hydroxide and sodium metaaluminate and the amorphous silicon sources such as sodium silicate, silica sol and fumed silica are reduced.

[0024] In the present invention, the MSE molecular sieve seeds are preferably MCM-68 molecular sieve or UZM-35 molecular sieve. There are no special requirements for the MCM-68 molecular sieve and UZM-35 molecular sieve in the present invention, and they can be obtained by using commercially available products or by using methods well-known to those skilled in the art. In the examples of the present invention, the MSE molecular sieve seeds used are MCM-68 molecular sieve, and the preparation method of the MCM-68 molecular sieve includes the following steps: (a) After mixing Al(OH)3, KOH and water for pretreatment, silica sol and the organic structure-directing agent N,N,N',N'-tetraethyl-exo,exo-bicyclo[2.2.2]oct-7-ene-2,3,5,6-bistetrahydropyrrol diiodide salt (TEBOP 2+ (I - )2) are added thereto to obtain a mixed material; (b) Hydrothermally crystallize the said mixed material; (c) Centrifuge, solid-phase wash and dry the hydrothermal crystallization system obtained in step (b) in sequence to obtain the said MCM-68 molecular sieve.

[0025] In the present invention, the preferred manner of mixing Al(OH)3, KOH and water in step (a) is: mix KOH and water to obtain an aqueous KOH solution; mix Al(OH)3 and the said aqueous KOH solution and stir for 2 h. In the present invention, the preferred temperature of the pretreatment is 100 °C, the preferred time is 12 h, and the temperature is reduced to room temperature after the pretreatment; the function of the pretreatment is to dissolve the aluminum source sufficiently and distribute it evenly. In the present invention, the silica sol is calculated in terms of SiO2, and the molar ratio of the effective components in the mixed material is: n (SiO2): n (Al(OH)3): n (KOH): n (SDA): n (H2O) = 1: 0.1: 0.375: 0.1: 30, where SDA represents the organic structure-directing agent TEBOP 2+ (I - )2. In the present invention, the preferred temperature of hydrothermal crystallization in step (b) is 160 °C, and the preferred time is 16 days.

[0026] In the present invention, the preferred method of mixing sodium hydroxide, potassium hydroxide, structure-directing agent, water, amorphous aluminum source, amorphous silica source, USY molecular sieve and MSE molecular sieve seeds is: First mix sodium hydroxide, potassium hydroxide, structure-directing agent with water to obtain a first mixed solution; Second mix the said first mixed solution with the amorphous aluminum source to obtain a second mixed solution; Third mix the said second mixed solution with the amorphous silica source to obtain a third mixed solution; Fourth mix the said third mixed solution with the USY molecular sieve to obtain a fourth mixed solution; Fifth mix the said fourth mixed solution with the MSE molecular sieve seeds to obtain the said mixed solution.

[0027] In the present invention, the structure-directing agent can be added in the form of an aqueous solution of the structure-directing agent. Specifically, sodium hydroxide, potassium hydroxide and the aqueous solution of the structure-directing agent are mixed, and then water is added thereto; in the examples of the present invention, the mass fraction of the aqueous solution of the structure-directing agent is 40%. In the present invention, sodium hydroxide, potassium hydroxide, the structure-directing agent and water are first mixed to maintain an alkaline solution environment, keep solubility, and make the structure-directing agent uniformly present in the solution. In the present invention, it is preferred to add the amorphous aluminum source to the first mixed solution for second mixing, add the amorphous silicon source to the second mixed solution for third mixing, add the USY molecular sieve to the third mixed solution for fourth mixing, and add the MSE molecular sieve seeds to the fourth mixed solution for fifth mixing. In the present invention, the first mixing, the second mixing, the third mixing, the fourth mixing and the fifth mixing are all preferably stirred and mixed at room temperature (i.e., without additional heating or cooling), and the stirring and mixing is based on mixing each raw material evenly.

[0028] In the present invention, the amorphous aluminum source is converted to Al(OH)3, the amorphous silicon source is converted to SiO2, the USY molecular sieve is converted to Al(OH)3 and SiO2, and the molar ratio of the effective components in the mixed solution is SiO2:Al(OH)3:structure-directing agent:sodium hydroxide:potassium hydroxide:water = 1:0.067:(0.45 - 0.60):(0.025 - 0.10):(0.10 - 0.20):(15 - 40), preferably 1:0.067:(0.45 - 0.60):0.05:0.15:30. The mass of the MSE molecular sieve seeds is 0.5 - 1.5% of the mass of SiO2, and can be 0.5%, 1.0% or 1.5%. By controlling the molar ratio of each raw material within the above range in the present invention, a pure-phase MSE crystal phase can be obtained. In the present invention, the addition amount of the MSE molecular sieve seeds is low, and at the same time, the addition amount of the structure-directing agent is also low.

[0029] After obtaining the mixed solution, in the present invention, the mixed solution is subjected to hydrothermal crystallization to obtain a crystallization product.

[0030] In the present invention, the temperature of the hydrothermal crystallization is preferably 150 - 200 °C, and can be 150, 160, 170, 180, 190 or 200 °C, and the time is preferably 96 - 168 h, more preferably 96 - 120 h. In the present invention, it is preferred to transfer the mixed solution to a hydrothermal autoclave for hydrothermal crystallization. The present invention can carry out hydrothermal crystallization at a lower temperature and in a shorter time.

[0031] After the hydrothermal crystallization is completed, in the present invention, it is preferred to sequentially centrifuge, wash the solid and dry the obtained crystallization reaction solution to obtain the crystallization product.

[0032] After obtaining the crystallization product, the present invention calcines the crystallization product to obtain the UZM-35 molecular sieve.

[0033] In the present invention, the calcination temperature is preferably 500-800 °C, which can be 550, 600 or 650 °C, and the time is preferably 6-12 h, which can be 6, 8 or 10 h. Through the calcination, the structure-directing agent in the molecular sieve is removed in the present invention.

[0034] The present invention provides a method for preparing UZM-35 molecular sieve based on zeolite transformation method. Using USY molecular sieve as the silicon source and aluminum source of UZM-35 molecular sieve, through hydrothermal synthesis, the aluminosilicate MSE molecular sieve - UZM-35 molecular sieve is obtained. The transformation process of zeolite transformation method from low framework density to high framework density structure has kinetic stability. At the same time, during the transformation process of USY molecular sieve, the construction of the molecular sieve framework occurs directly, without spontaneous nucleation from amorphous silica-alumina gel, and the energy barrier of the depolymerization-recombination path is low, and the crystallization rate is faster. The preparation method provided by the present invention is fast and efficient, and can obtain UZM-35 molecular sieve with a low seed addition amount and a short crystallization period. The preparation cost is low, and it is easy to realize mass production. Moreover, the crystallinity of the prepared UZM-35 molecular sieve is good (relative crystallinity is 100%).

[0035] To further illustrate the present invention, the following examples are used to describe in detail the preparation method of the UZM-35 molecular sieve provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0036] In each example, X-ray diffraction analysis (XRD) was used to detect the phase structure with a D8 Advance type X-ray powder diffractometer from Bruker, Germany. Cu target Kα radiation (wavelength λ = 1.5418 Å) was selected, the tube current and tube voltage were 40 mA and 40 kV, the diffraction angle 2θ scanning range was 5°-50°, and the scanning rate was controlled at 10° / min; field emission scanning electron microscopy (SEM) used a Namo SEM 450 type field emission scanning electron microscope from Feiyu Technology Co., Ltd., USA, for the characterization of the microscopic morphology of the sample. The sample was attached to the conductive adhesive and subjected to platinum plating treatment for 90 s.

[0037] In each example, the MCM-68 seeds were obtained by the following preparation method: Mix Al(OH)3 with an aqueous KOH solution, continuously stir for 2 h to fully dissolve it, transfer it to a reaction kettle and pretreat it at 100 °C for 12 h. After cooling to room temperature, add silica sol and the organic structure-directing agent N,N,N',N'-tetraethyl-exo,exo-bicyclo[2.2.2]oct-7-ene-2,3,5,6-bistetrahydropyrrolidium diiodide (TEBOP 2+ (I -)2), the molar composition ratio of the raw materials is n (SiO2): n (Al(OH)3): n (KOH): n (SDA): n (H2O) = 1:0.1:0.375:0.1:30, where SDA represents the structure-directing agent TEBOP 2+ (I - )2; then hydrothermal crystallization is carried out at 160 °C for 16 days. After the crystallization product is centrifuged, washed, and dried, MCM-68 molecular sieve, that is, MCM-68 seed crystal, is obtained.

[0038] Example 1 Using dimethyldiallylammonium hydroxide as the structure-directing agent and USY molecular sieve (silica-alumina ratio (Si / Al) = 15, purchased from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum source and silicon source, MSE molecular sieve - UZM-35 molecular sieve is synthesized. The steps are as follows: (1) Add 0.208 g of NaOH (96 wt%) and 0.842 g of KOH to 16.113 g of a 40 wt% aqueous solution of dimethyldiallylammonium hydroxide (structure-directing agent, SDA), and then add 36.736 g of deionized water, and stir for 2 h; (2) Add 0.443 g of Al(OH)3 to the solution obtained in step (1), and stir for 2 h; (3) Add 12.721 g of silica sol (Ludox HS-40) to the solution obtained in step (2), and stir until a homogeneous gel state is formed; (4) Add 1 g of USY molecular sieve (silica-alumina ratio = 15) to the solution obtained in step (3), and stir for 3 h; (5) Add MCM-68 seed crystal to the solution obtained in step (4), and stir to form a homogeneous solution. The molar composition ratio of the raw materials is SiO2:Al(OH)3:SDA:NaOH:KOH:H2O = 1:0.067:0.45:0.05:0.15:30, and the mass of the MCM-68 seed crystal is 1.0% of the mass of SiO2; (6) Transfer the solution obtained in step (5) to a hydrothermal autoclave, and carry out hydrothermal crystallization at 170 °C for 96 h; centrifuge, wash, and dry the obtained solid, and calcine it at 550 °C for 6 h to obtain UZM-35 molecular sieve, marked as UZM-35-IZC, and its XRD pattern is shown in Figure 1 . The sample is at 2 θThe characteristic diffraction peaks of MSE appear at 6.79°, 8.06°, 8.72°, 9.66°, 19.36°, 21.62°, 26.14° and 27.50°, and there are no other miscellaneous peaks, that is, pure-phase UZM-35 molecular sieve is successfully prepared.

[0039] Example 2 Using dimethyldiallylammonium hydroxide as the structure-directing agent and USY molecular sieve (silica-alumina ratio (Si / Al) = 15, obtained from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum source and silicon source, MSE molecular sieve - UZM-35 molecular sieve was synthesized as follows: (1) Add 0.208 g of NaOH (96 wt%) and 0.842 g of KOH to 16.113 g of a 40 wt% aqueous solution of dimethyldiallylammonium hydroxide (structure-directing agent, SDA), and then add 36.736 g of deionized water and stir for 2 h; (2) Add 0.443 g of Al(OH)3 to the solution obtained in step (1) and stir for 2 h; (3) Add 12.721 g of silica sol (Ludox HS-40) to the solution obtained in step (2) and stir until a homogeneous gel state is reached; (4) Add 1 g of USY molecular sieve (silica-alumina ratio = 15) to the solution obtained in step (3) and stir for 3 h; (5) Add MCM-68 seeds to the solution obtained in step (4) and stir to form a homogeneous solution. The molar composition ratio of the raw materials is SiO2:Al(OH)3:SDA:NaOH:KOH:H2O = 1:0.067:0.45:0.05:0.15:30, and the mass of the MCM-68 seeds is 1.0% of the mass of SiO2; (6) Transfer the solution obtained in step (5) to a hydrothermal autoclave and hydrothermally crystallize at 150 °C for 168 h; centrifuge, wash and dry the obtained solid, and calcine at 550 °C for 6 h to obtain UZM-35 molecular sieve. Its XRD pattern is shown in Figure 2 . The sample at 2 θ The characteristic diffraction peaks of MSE appear at 6.79°, 8.06°, 8.72°, 9.66°, 19.36°, 21.62°, 26.14° and 27.50°, and there are no other miscellaneous peaks, that is, pure-phase UZM-35 molecular sieve is successfully prepared.

[0040] Example 3 Using dimethyldiallylammonium hydroxide as the structure-directing agent and USY molecular sieve (silica-alumina ratio (Si / Al) = 30, obtained from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum source and silicon source, MSE molecular sieve - UZM-35 molecular sieve was synthesized as follows: (1) Add 0.208 g of NaOH (96 wt%) and 0.842 g of KOH to 16.113 g of a 40 wt% aqueous solution of dimethyldiallylammonium hydroxide (structure-directing agent, SDA), then add 36.075 g of deionized water, and stir for 2 h; (2) Add 0.502 g of Al(OH)3 to the solution obtained in step (1), and stir for 2 h; (3) Add 13.823 g of silica sol (Ludox HS-40) to the solution obtained in step (2), and stir until a homogeneous gel state is reached; (4) Add 0.5 g of USY zeolite (Si / Al ratio = 30) to the solution obtained in step (3), and stir for 3 h; (5) Add MCM-68 seed crystals to the solution obtained in step (4), and stir to form a homogeneous solution. The molar composition ratio of the raw materials is SiO2:Al(OH)3:SDA:NaOH:KOH:H2O = 1:0.067:0.45:0.05:0.15:30, and the mass of the MCM-68 seed crystals is 1.0% of the mass of SiO2; (6) Transfer the solution obtained in step (5) to a hydrothermal autoclave, and carry out hydrothermal crystallization at 170 °C for 120 h; centrifuge, wash, and dry the obtained solid, and calcine it at 550 °C for 6 h to obtain UZM-35 zeolite. Its XRD pattern is shown in Figure 3 . The sample shows characteristic diffraction peaks of MSE at 2 θ at 6.79°, 8.06°, 8.72°, 9.66°, 19.36°, 21.62°, 26.14°, and 27.50°, and there are no other impurity peaks, that is, pure-phase UZM-35 zeolite is successfully prepared.

[0041] Example 4 Using diethyldimethylammonium hydroxide as the structure-directing agent and USY zeolite (Si / Al ratio (Si / Al) = 15, purchased from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum source and silicon source, MSE zeolite - UZM-35 zeolite was synthesized as follows: (1) Add 0.208 g of NaOH (96 wt%) and 0.842 g of KOH to 17.882 g of a 40 wt% aqueous solution of diethyldimethylammonium hydroxide (structure-directing agent, SDA), then add 35.675 g of deionized water, and stir for 2 h; (2) Add 0.443 g of Al(OH)3 to the solution obtained in step (1), and stir for 2 h; (3) Add 12.721 g of silica sol (Ludox HS-40) to the solution obtained in step (2), and stir until a homogeneous gel state is reached; (4) Add 1 g of USY molecular sieve (silica-alumina ratio = 15) to the solution obtained in step (3), and stir for 3 h; (5) Add MCM-68 seed crystals to the solution obtained in step (4), stir to form a homogeneous solution, and the molar composition ratio of the raw materials is SiO2:Al(OH)3:SDA:NaOH:KOH:H2O = 1:0.067:0.60:0.05:0.15:30. The mass of the MCM-68 seed crystals is 1.0% of the mass of SiO2; (6) Transfer the solution obtained in step (5) to a hydrothermal autoclave, and carry out hydrothermal crystallization at 170 °C for 120 h; centrifuge, wash, and dry the obtained solid, and calcine it at 550 °C for 6 h to obtain UZM-35 molecular sieve. Its XRD pattern is shown in Figure 4 . The sample shows characteristic diffraction peaks of MSE at 2 θ at 6.79°, 8.06°, 8.72°, 9.66°, 19.36°, 21.62°, 26.14°, and 27.50°, and there are no other impurity peaks, that is, pure-phase UZM-35 molecular sieve is successfully prepared.

[0042] Comparative Example 1 Preparation of UZM-35 molecular sieve (seed-induced method), the steps are as follows: Add NaOH (96 wt%) and KOH to an aqueous solution of 40 wt% dimethyldiallylammonium hydroxide (structure-directing agent, SDA), then add deionized water, and stir for 2 h to dissolve; then add Al(OH)3 and stir for 2 h, and then add Ludox HS-40 silica sol, stir for 2 h, and then add MCM-68 seed crystals and stir well for 5 h. The obtained gel is hydrothermally crystallized at 180 °C for 7 days (168 h), and the molar composition ratio of the raw materials is n (SiO2): n (Al(OH)3): n (SDA): n (NaOH): n (KOH): n (H2O)=1:0.067:0.45:0.05:0.15:30. The mass of the MCM-68 seed crystals is 10% of the mass of SiO2; Wash, dry the crystallization product obtained by hydrothermal crystallization, and calcine it at 550 °C for 6 h to obtain UZM-35 molecular sieve, labeled as UZM-35-SAC.

[0043] The XRD patterns of the UZM-35 molecular sieves prepared by different synthesis routes in Example 1 and Comparative Example 1 are shown in Figure 5 ( Figure 5 where RC represents relative crystallinity), and the SEM images are shown in Figure 6 , Figure 6Figure (a) is the SEM image of UZM-35 molecular sieve obtained by the zeolite conversion method in Example 1, and figure (b) is the SEM image of UZM-35 molecular sieve obtained by the seed-induced method in Comparative Example 1. From Figure 5 It can be seen that the relative crystallinity of the UZM-35 molecular sieve obtained by the zeolite conversion method in Example 1 is 100%, and the crystal phase purity is high. While the relative crystallinity of UZM-35 obtained by the seed-induced method in Comparative Example 1 is 95%. From Figure 6 It can be seen that the morphology of the UZM-35 molecular sieve obtained by the zeolite conversion method in Example 1 presents a unique layered stacking structure, formed by mutually intersecting homogeneous sheet-like units, with a particle size of 700~1300 nm. The UZM-35 molecular sieve pair has a higher crystallinity, while there are more dispersed nanocrystals on the UZM-35 molecular sieve obtained by the seed-induced method in Comparative Example 1.

[0044] In Example 1, the feeding amount of MCM-68 seeds in the zeolite conversion synthesis route is 1.0% of the mass of SiO2, and the crystallization time is only 4 days. Compared with the MSE synthesis route by the seed-induced method, the dosage of MCM-68 seeds in the zeolite conversion synthesis route is reduced by more than 95 wt%, and the crystallization time is shortened by more than 40%, greatly reducing the synthesis cost and cycle of the UZM-35 molecular sieve.

[0045] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing UZM-35 molecular sieve, characterized in that, It includes the following steps: Mix sodium hydroxide, potassium hydroxide, a structure-directing agent, water, an amorphous aluminum source, an amorphous silicon source, USY zeolite and MSE zeolite seeds to obtain a mixed solution; the structure-directing agent is at least one of monoquaternary ammonium salt compounds of the following groups: diethyldimethyl, dimethyldipropyl, dimethyldiethylenyl, dimethyldiallyl, dimethyldibutenyl, diethyldiethylenyl, diethyldiallyl, diethyldibutenyl; the amorphous aluminum source is converted to Al(OH)3, the amorphous silicon source is converted to SiO2, the USY zeolite is converted to Al(OH)3 and SiO2, and the molar ratio of the active components in the mixed solution is SiO2:Al(OH)3:structure-directing agent:sodium hydroxide:potassium hydroxide:water = 1:0.067:(0.45 - 0.60):(0.025 - 0.10):(0.10 - 0.20):(15 - 40), and the mass of the MSE zeolite seeds is 0.5 - 1.5% of the mass of SiO2; Perform hydrothermal crystallization on the mixed solution to obtain a crystallized product; Calcine the crystallized product to obtain the UZM-35 zeolite.

2. The preparation method according to claim 1, wherein The monoquaternary ammonium salt compound is an ammonium hydroxide or ammonium halide compound of the group.

3. The preparation method according to claim 1, wherein, The amorphous aluminum source is one or more of aluminum sulfate, aluminum hydroxide and sodium metaaluminate.

4. The preparation method according to claim 1, wherein, The amorphous silicon source is one or more of sodium silicate, silica sol and fumed silica.

5. The preparation method according to claim 1, characterized in that, The silicon-aluminum ratio of the USY zeolite is 15 - 30, and the silicon-aluminum ratio is the molar ratio of silicon element to aluminum element.

6. The preparation method according to claim 1, wherein, The MSE zeolite seeds are MCM-68 zeolite or UZM-35 zeolite.

7. The preparation method according to claim 1 or 6, characterized in that, The mass of the MSE zeolite seeds is 1% of the mass of SiO2.

8. The preparation method according to any one of claims 1 to 6, characterized in that, The method of mixing is as follows: Perform a first mixing of sodium hydroxide, potassium hydroxide, the structure-directing agent and water to obtain a first mixed solution; Perform a second mixing of the first mixed solution and the amorphous aluminum source to obtain a second mixed solution; Perform a third mixing of the second mixed solution and the amorphous silicon source to obtain a third mixed solution; Perform a fourth mixing of the third mixed solution and the USY zeolite to obtain a fourth mixed solution; Perform a fifth mixing of the fourth mixed solution and the MSE zeolite seeds to obtain the mixed solution.

9. The preparation method according to claim 1, characterized in that, The temperature of the hydrothermal crystallization is 150 - 200 °C, and the time is 96 - 168 h.

10. The preparation method according to claim 1, characterized in that, The temperature of the calcination is 500 - 800 °C, and the time is 6 - 12 h.

Images