A preparation method of UZM-35 molecular sieve

Abstract

The present invention provides a preparation method of UZM-35 molecular sieve, relating to the field of molecular sieve technology. The present invention mixes 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, and the resulting mixed solution is subjected to hydrothermal crystallization to obtain a crystallized product; The crystallized product is roasted to obtain a UZM-35 molecular sieve. The present invention introduces a USY molecular sieve to provide a silicon source and an aluminum source, and prepares a UZM-35 molecular sieve using a zeolite crystallization method, supplemented with a monoquaternary ammonium salt compound of a group such as dimethyldipropyl as a structure directing agent, thereby achieving a quick and efficient preparation of a UZM-35 molecular sieve (crystallization time can be shortened to 96h), and significantly reduces the amount of seed crystals (the amount of seed crystals is only 0.5~1.5% of SiO2 mass), thereby improving preparation efficiency and reducing preparation cost.

Description

Technical Field

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

[0002] Catalysts are a key factor influencing the effectiveness of catalytic cracking to produce light olefins. Molecular sieves, due to their unique pore structure, tunable acidic sites, and strong resistance to carbon deposition, are the catalyst of choice for catalytic cracking reaction systems. Molecular sieve frameworks with ten- and twelve-membered ring pores have been shown to be more suitable for hydrocarbon catalytic cracking of light olefins. Therefore, molecular sieves with MSE topologies that combine ten- and twelve-membered rings have development value and application potential in catalytic cracking.

[0003] The MSE type zeolite was first proposed by Mobil Corporation in the United States in 2000. The characteristic structure of the MSE zeolite consists of the following three parts: (1) The main pore channel is a straight channel of twelve-membered rings (12-MR) extending along a specific crystal axis, with a pore size of approximately 0.65nm×0.70nm; (2) The secondary pore channel is three-dimensionally intersected with the main pore channel through two independent ten-membered rings (10-MR, pore size of approximately 0.51nm×0.55nm), forming a diffusion network; (3) The supercage system (18×12R) is connected to the secondary pore channel only through 10-MR and cannot be directly entered from the main pore channel. The size is approximately 1.2nm×1.8nm. MCM-68 and UZM-35 are typical zeolites with MSE topology. The UZM-35 zeolite has a three-dimensional pore system containing 12-MR and 10-MR channels and was first proposed by UOP Corporation in the United States in 2010. Compared with MCM-68 zeolite, UZM-35 zeolite is synthesized under milder conditions, has a higher silicon-aluminum ratio, and exhibits good hydrothermal stability. The researchers used spectroscopic methods combined with catalytic activity evaluation to study the differences in the location and distribution of Brønsted acid sites in UZM-35 and MCM-68 zeolites. 27 Al MAS NMR and FT-IR spectroscopy revealed that 61% of the acidic active sites in MCM-68 are located in the 12-MR channel, while this proportion is only 33% in UZM-35, which has a higher number of acid sites in the 10-MR channel. Calculation of the n-hexane / 3-methylpentane ratio revealed that UZM-35 has a lower cracking constraint index than MCM-68, resulting in higher butene selectivity in 1-octene cracking, while MCM-68 favors BTX (benzene, toluene, and xylene) products. Although UZM-35 exhibits superior performance in catalytic cracking, its industrialization still faces key bottlenecks compared to the mainstream ZSM-5 zeolite.

[0004] The classic hydrothermal synthesis method of UZM-35 molecular sieve was developed by Mobil Corporation. It is mainly based on the promotion of crystallization by structure-directing agents, without the need for seed crystals. 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-tetrahydropyrrole diiodide ammonium salt (TEBOP 2+ (I - ) 2) As a structure-directing agent, it combines with silica-alumina sources (such as silica sol, sodium aluminate) and inorganic bases to form a gel. However, TEBOP 2+ (I - )2 Synthesis costs are high, the synthesis cycle is long, and the crystallization time required to prepare UZM-35 molecular sieve using this structure-directing agent is long (>14 days). This limits the preparation efficiency of MSE molecular sieves and increases the preparation cost. Introducing seed crystals into the molecular sieve synthesis system, known as the seed induction method, can shorten the synthesis cycle to a certain extent. However, the current amount of seed crystals required is relatively large, typically requiring more than 3% by weight of the silicon source (calculated as SiO2), or even as high as 15%, to achieve their corresponding effect, which further increases the synthesis cost of the molecular sieve. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a method for preparing UZM-35 molecular sieve. The method for preparing UZM-35 molecular sieve provided by the present invention can shorten the crystallization time, reduce the preparation cost, and require less amount of seed crystals.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing UZM-35 molecular sieve, comprising the following steps:

[0008] Sodium hydroxide, potassium hydroxide, a structure directing agent, water, an amorphous aluminum source, an amorphous silicon source, USY molecular sieve and MSE molecular sieve seed crystals are mixed to obtain a mixed solution; the structure directing agent is at least one of the following monoquaternary ammonium salt compounds: diethyldimethyl, dimethyldipropyl, dimethyldiallylethyl, dimethyldiallyl, dimethyldiallylbutyl, diethyldiallylethyl, diethyldiallyl, diethyldiallylbutyl; the amorphous aluminum source is converted to Al(OH)3, the The amorphous silicon source is converted to SiO2, the USY molecular sieve is converted to Al(OH)3 and SiO2, the molar ratio of the effective ingredients 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 molecular sieve seed crystal is 0.5~1.5% of the mass of SiO2;

[0009] performing hydrothermal crystallization on the mixed solution to obtain a crystallized product;

[0010] The crystallized product is calcined to obtain the UZM-35 molecular sieve.

[0011] Preferably, the monoquaternary ammonium salt compound is an ammonium hydroxide or ammonium halide compound of the group.

[0012] Preferably, the amorphous aluminum source is one or more of aluminum sulfate, aluminum hydroxide and sodium metaaluminate.

[0013] Preferably, the amorphous silicon source is one or more of sodium silicate, silica sol and white carbon black.

[0014] Preferably, the silicon-aluminum ratio of the USY molecular sieve is 15-30, where the silicon-aluminum ratio is the molar ratio of silicon to aluminum.

[0015] Preferably, the MSE molecular sieve seed crystals are MCM-68 molecular sieve or UZM-35 molecular sieve.

[0016] Preferably, the mass of the MSE molecular sieve seed crystal is 1% of the mass of SiO2.

[0017] Preferably, the mixing method is:

[0018] mixing sodium hydroxide, potassium hydroxide, a structure directing agent and water to obtain a first mixed solution;

[0019] performing a second mixing of the first mixed solution and an amorphous aluminum source to obtain a second mixed solution;

[0020] performing a third mixing of the second mixed liquid and an amorphous silicon source to obtain a third mixed liquid;

[0021] Mixing the third mixed solution with USY molecular sieve for the fourth time to obtain a fourth mixed solution;

[0022] The fourth mixed liquid is mixed with MSE molecular sieve seed crystals for a fifth time to obtain the mixed liquid.

[0023] Preferably, the hydrothermal crystallization temperature is 150-200° C., and the time is 96-168 h.

[0024] Preferably, the calcination temperature is 500-800° C. and the calcination time is 6-12 hours.

[0025] The invention provides a preparation method of UZM-35 molecular sieve. Compared with the prior art, the invention has the following beneficial effects: the invention prepares the UZM-35 molecular sieve by a zeolite crystallization method, introduces USY molecular sieve to provide a silicon source and an aluminum source, and uses a monoquaternary ammonium salt compound of diethyldimethyl, dimethyldipropyl, dimethyldiallyl, dimethyldiallylbutyl, diethyldiallylethyl, diethyldiallyl, and diethyldiallylbutyl as a structure-directing agent. The invention can realize fast and efficient preparation of the UZM-35 molecular sieve (crystallization time can be shortened to 96 hours), and can significantly reduce the amount of seed crystals added, which is only 0.5-1.5% of the mass of SiO2, thereby improving preparation efficiency, reducing preparation cost, and facilitating mass production of the UZM-35 molecular sieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The XRD spectrum of the UZM-35 molecular sieve prepared in Example 1 is shown in FIG.

[0027] Figure 2 This is the XRD spectrum of the UZM-35 molecular sieve prepared in Example 2;

[0028] Figure 3 This is the XRD spectrum of the UZM-35 molecular sieve prepared in Example 3;

[0029] Figure 4 This is the XRD spectrum of the UZM-35 molecular sieve prepared in Example 4;

[0030] Figure 5 The XRD spectra of the UZM-35 molecular sieves prepared in Example 1 and Comparative Example 1 are shown;

[0031] Figure 6 The SEM images of the UZM-35 molecular sieves prepared in Example 1 and Comparative Example 1 are shown. Figure 6 (a) is a SEM image of the UZM-35 molecular sieve obtained by the zeolite crystallization method in Example 1, and (b) is a SEM image of the UZM-35 molecular sieve obtained by the seed crystal induction method in Comparative Example 1. DETAILED DESCRIPTION

[0032] The present invention provides a method for preparing UZM-35 molecular sieve, comprising the following steps:

[0033] Sodium hydroxide, potassium hydroxide, a structure directing agent, water, an amorphous aluminum source, an amorphous silicon source, USY molecular sieve and MSE molecular sieve seed crystals are mixed to obtain a mixed solution; the structure directing agent is at least one of the following monoquaternary ammonium salt compounds: diethyldimethyl, dimethyldipropyl, dimethyldiallylethyl, dimethyldiallyl, dimethyldiallylbutyl, diethyldiallylethyl, diethyldiallyl, diethyldiallylbutyl; the amorphous aluminum source is converted to Al(OH)3, the The amorphous silicon source is converted to SiO2, the USY molecular sieve is converted to Al(OH)3 and SiO2, the molar ratio of the effective ingredients 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 molecular sieve seed crystal is 0.5~1.5% of the mass of SiO2;

[0034] performing hydrothermal crystallization on the mixed solution to obtain a crystallized product;

[0035] The crystallized product is calcined to obtain the UZM-35 molecular sieve.

[0036] In the present invention, unless otherwise specified, all raw materials involved are commercially available products well known in the art.

[0037] The invention mixes sodium hydroxide (NaOH), potassium hydroxide (KOH), a structure directing agent, water, an amorphous aluminum source, an amorphous silicon source, a USY molecular sieve and an MSE molecular sieve seed to obtain a mixed solution.

[0038] In the present invention, the sodium hydroxide and potassium hydroxide provide an alkaline synthesis system. The present invention adds two alkaline sources, sodium hydroxide and potassium hydroxide, and utilizes the unique properties of potassium ions and sodium ions and their synergistic effects to achieve the purpose of controlling the synthesis process and optimizing the product structure and performance; wherein, K + Tends to stabilize molecular sieve structures with larger cavities or windows, Na + It is more suitable for medium-sized pores and cages. Since UZM-35 molecular sieve has both 10-membered rings and 12-membered rings, it needs to be co-doped with K and Na. In the present invention, the water is preferably deionized water.

[0039] In the present invention, the structure directing agent is at least one of the following groups of monoquaternary ammonium salt compounds: diethyldimethyl, dimethyldipropyl, dimethyldiallylethyl, dimethyldiallyl, dimethyldiallylbutyl, diethyldiallylethyl, diethyldiallyl, diethyldiallylbutyl; the monoquaternary ammonium salt compound is preferably an ammonium hydroxide or ammonium halide compound of the group; when the monoquaternary ammonium salt compound is an ammonium hydroxide compound of the group, the monoquaternary ammonium salt compound is specifically: diethyldimethylammonium hydroxide, dimethyldipropylammonium hydroxide, dimethyldiallylethylammonium hydroxide, dimethyldiallylammonium hydroxide, dimethyldiallylbutylammonium hydroxide, diethyldiallylethylammonium hydroxide, diethyldiallyl Ammonium hydroxide, diethyldiallylbutylammonium 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, dimethyldiallylethylammonium halide, dimethyldiallylammonium halide, dimethyldiallylbutylammonium halide, diethyldiallylethylammonium halide, diethyldiallylammonium halide, and diethyldiallylbutylammonium halide. The halogen element in the diethyldimethylammonium halide, dimethyldipropylammonium halide, dimethyldiallylethylammonium halide, dimethyldiallylbutylammonium halide, diethyldiallylethylammonium halide, diethyldiallylammonium halide and diethyldiallylbutylammonium halide is preferably chlorine or bromine.

[0040] 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 white carbon black; and the silicon-to-aluminum ratio of the USY molecular sieve is preferably 15-30, where the silicon-to-aluminum ratio is the molar ratio of silicon to aluminum (i.e., Si / Al). The present invention introduces USY molecular sieve and uses the zeolite crystallization method to prepare UZM-35 molecular sieve. In the actual batching process, the USY molecular sieve is used as the primary silicon and aluminum source, thereby reducing the amount of amorphous aluminum sources such as aluminum sulfate, aluminum hydroxide, and sodium metaaluminate, and amorphous silicon sources such as sodium silicate, silica sol, and white carbon black.

[0041] In the present invention, the MSE molecular sieve seed crystal is preferably MCM-68 molecular sieve or UZM-35 molecular sieve. The present invention has no special requirements for the MCM-68 molecular sieve and UZM-35 molecular sieve, and they can be prepared using commercially available products or methods well known to those skilled in the art. In an embodiment of the present invention, the MSE molecular sieve seed crystal used is MCM-68 molecular sieve, and the preparation method of the MCM-68 molecular sieve comprises the following steps:

[0042] (a) After pretreatment with a mixture of Al(OH)3, KOH, and water, silica sol and an organic structure-directing agent, N,N,N',N'-tetraethyl-exo,exo-bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetrahydropyrrole diiodide ammonium salt (TEBOP) were added. 2+ (I - )2), obtaining a mixture;

[0043] (b) subjecting the mixture to hydrothermal crystallization;

[0044] (c) The hydrothermal crystallization system obtained in step (b) is centrifuged, solid-phase washed, and dried in sequence to obtain the MCM-68 molecular sieve.

[0045] In the present invention, the method for mixing Al(OH)3, KOH, and water in step (a) is preferably: mixing KOH and water to obtain a KOH aqueous solution; then mixing Al(OH)3 and the KOH aqueous solution and stirring for 2 hours. In the present invention, the pretreatment temperature is preferably 100°C and the time is preferably 12 hours, and the temperature is lowered to room temperature after the pretreatment. The purpose of the pretreatment is to fully dissolve and evenly distribute the aluminum source. In the present invention, the silica sol is converted to SiO2, and the molar ratio of the active ingredients in the mixture 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 temperature of the hydrothermal crystallization in step (b) is preferably 160° C., and the time is preferably 16 days.

[0046] In the present invention, the method of mixing the sodium hydroxide, potassium hydroxide, structure directing agent, water, amorphous aluminum source, amorphous silicon source, USY molecular sieve and MSE molecular sieve seed crystals is preferably:

[0047] mixing sodium hydroxide, potassium hydroxide, a structure directing agent and water to obtain a first mixed solution;

[0048] performing a second mixing of the first mixed solution and an amorphous aluminum source to obtain a second mixed solution;

[0049] performing a third mixing of the second mixed liquid and an amorphous silicon source to obtain a third mixed liquid;

[0050] Mixing the third mixed solution with USY molecular sieve for the fourth time to obtain a fourth mixed solution;

[0051] The fourth mixed liquid is mixed with MSE molecular sieve seed crystals for a fifth time to obtain the mixed liquid.

[0052] 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. In an embodiment of the present invention, the mass fraction of the aqueous solution of the structure-directing agent is 40%. In the present invention, the sodium hydroxide, potassium hydroxide, and the structure-directing agent are first mixed with water to maintain an alkaline solution environment, maintain solubility, and ensure that the structure-directing agent is uniformly present in the solution. In the present invention, the amorphous aluminum source is preferably added to the first mixed solution for the second mixing, the amorphous silicon source is added to the second mixed solution for the third mixing, the USY molecular sieve is added to the third mixed solution for the fourth mixing, and the MSE molecular sieve seed crystals are added to the fourth mixed solution for the fifth mixing. In the present invention, the first, second, third, fourth, and fifth mixing are preferably performed by stirring and mixing at room temperature (i.e., without additional heating or cooling), and the stirring and mixing is based on uniform mixing of the various raw materials.

[0053] 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 ingredients 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, and the mass of the MSE molecular sieve seed crystal is 0.5~1.5% of the mass of SiO2, and can be 0.5%, 1.0% or 1.5%. The present invention controls the molar ratio of each raw material within the above range to obtain a pure MSE crystal phase. In the present invention, the amount of the MSE molecular sieve seed crystals added is low, and the amount of the structure directing agent added is also low.

[0054] After obtaining the mixed solution, the present invention performs hydrothermal crystallization on the mixed solution to obtain a crystallized product.

[0055] In the present invention, the hydrothermal crystallization temperature is preferably 150-200°C, and may be 150, 160, 170, 180, 190, or 200°C. The time is preferably 96-168 hours, and more preferably 96-120 hours. The present invention preferably transfers the mixed solution to a hydrothermal kettle for hydrothermal crystallization. The present invention enables hydrothermal crystallization to be performed at a lower temperature and in a shorter time.

[0056] After the hydrothermal crystallization is completed, the present invention preferably centrifuges the obtained crystallization reaction solution, washes the solid, and then dries it to obtain the crystallized product.

[0057] After obtaining the crystallized product, the present invention calcines the crystallized product to obtain the UZM-35 molecular sieve.

[0058] In the present invention, the calcination temperature is preferably 500-800°C, and may be 550, 600 or 650°C, and the calcination time is preferably 6-12 hours, and may be 6, 8 or 10 hours. The present invention removes the structure directing agent in the molecular sieve through the calcination.

[0059] The present invention provides a method for preparing UZM-35 molecular sieve based on the zeolite crystallization method, in which USY molecular sieve is used as the silicon source and aluminum source of the UZM-35 molecular sieve, and a silicate MSE molecular sieve, UZM-35 molecular sieve, is obtained through hydrothermal synthesis. The transformation process from a low skeleton density to a high skeleton density structure by the zeolite crystallization method is kinetically stable. At the same time, the molecular sieve skeleton is directly constructed during the crystallization process of the USY molecular sieve, without the need for spontaneous nucleation from an amorphous silica-alumina gel. The depolymerization-recombination path has a low energy barrier and a faster crystallization rate. The preparation method provided by the present invention is fast and efficient, and can obtain UZM-35 molecular sieve with a lower seed addition amount and a shorter crystallization cycle. The preparation cost is low, and batch production is easy to achieve. In addition, the prepared UZM-35 molecular sieve has good crystallinity (relative crystallinity is 100%).

[0060] In order to further illustrate the present invention, the preparation method of the UZM-35 molecular sieve provided by the present invention is described in detail below with reference to examples, but they should not be construed as limiting the scope of protection of the present invention.

[0061] In each embodiment, X-ray diffraction analysis (XRD) was performed using a D8 Advance X-ray polycrystal diffractometer from Bruker, Germany, using Cu target Kα radiation (wavelength λ = 1.5418 Å), tube current and tube voltage were 40 mA and 40 kV, the diffraction angle 2θ scanning range was 5° to 50°, and the scanning rate was controlled at 10° / min; a field emission scanning electron microscope (SEM) using a Namo SEM 450 field emission scanning electron microscope from Feiyu Technology Co., Ltd., USA, was used to characterize the micromorphology of the samples. The samples were attached to a conductive adhesive and platinum-plated for 90 s.

[0062] In each embodiment, the MCM-68 seed crystals were obtained by the following preparation method:

[0063] Al(OH)3 was mixed with KOH aqueous solution and stirred continuously for 2 h to fully dissolve it. The mixture was transferred to a reactor and pretreated at 100 °C for 12 h. After cooling to room temperature, silica sol and organic structure directing agent N,N,N',N'-tetraethyl-exo, exo-bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetrahydropyrrole diiodide ammonium salt (TEBOP) were added. 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 hydrothermally crystallize at 160°C for 16 days, and the crystallized product is centrifuged, washed, and dried to obtain MCM-68 molecular sieve, namely MCM-68 seed crystals.

[0064] Example 1

[0065] MSE molecular sieve, UZM-35 molecular sieve, was synthesized using dimethyldiallylammonium hydroxide as a structure-directing agent and USY molecular sieve (silicon-aluminum ratio (Si / Al) = 15, sourced from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum and silicon sources. The steps are as follows:

[0066] (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 36.736 g of deionized water and stir for 2 h.

[0067] (2) Add 0.443 g of Al(OH)3 to the solution obtained in step (1) and stir for 2 h;

[0068] (3) Add 12.721 g of silica sol (Ludox HS-40) to the solution obtained in step (2) and stir until a uniform gel state is obtained;

[0069] (4) Add 1 g of USY molecular sieve (silicon to aluminum ratio = 15) to the solution obtained in step (3) and stir for 3 h;

[0070] (5) adding MCM-68 seed crystals to the solution obtained in step (4) and stirring to form a uniform solution, wherein 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;

[0071] (6) The solution obtained in step (5) was transferred to a hydrothermal reactor and hydrothermally crystallized at 170°C for 96 hours. The obtained solid was centrifuged, washed, dried, and calcined at 550°C for 6 hours to obtain UZM-35 molecular sieve, which was labeled as UZM-35-IZC. Its XRD spectrum is shown in FIG. Figure 1 . Samples in 2 θ 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 impurity peaks, which means that pure phase UZM-35 molecular sieve is successfully prepared.

[0072] Example 2

[0073] MSE molecular sieve, UZM-35 molecular sieve, was synthesized using dimethyldiallylammonium hydroxide as a structure-directing agent and USY molecular sieve (silicon-aluminum ratio (Si / Al) = 15, sourced from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum and silicon sources. The steps are as follows:

[0074] (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 36.736 g of deionized water and stir for 2 h;

[0075] (2) Add 0.443 g of Al(OH)3 to the solution obtained in step (1) and stir for 2 h;

[0076] (3) Add 12.721 g of silica sol (Ludox HS-40) to the solution obtained in step (2) and stir until a uniform gel state is obtained;

[0077] (4) Add 1 g of USY molecular sieve (silicon to aluminum ratio = 15) to the solution obtained in step (3) and stir for 3 h;

[0078] (5) adding MCM-68 seed crystals to the solution obtained in step (4) and stirring to form a uniform solution, wherein 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;

[0079] (6) The solution obtained in step (5) was transferred to a hydrothermal reactor and hydrothermally crystallized at 150°C for 168 hours. The obtained solid was centrifuged, washed, dried, and calcined at 550°C for 6 hours to obtain UZM-35 molecular sieve, whose XRD spectrum is shown in FIG. Figure 2 . Samples in 2 θ 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 impurity peaks, which means that pure phase UZM-35 molecular sieve is successfully prepared.

[0080] Example 3

[0081] MSE molecular sieve, UZM-35 molecular sieve, was synthesized using dimethyldiallylammonium hydroxide as a structure-directing agent and USY molecular sieve (silicon-aluminum ratio (Si / Al) = 30, sourced from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum and silicon sources. The steps are as follows:

[0082] (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.

[0083] (2) Add 0.502 g of Al(OH)3 to the solution obtained in step (1) and stir for 2 h;

[0084] (3) Add 13.823 g of silica sol (Ludox HS-40) to the solution obtained in step (2) and stir until a uniform gel state is obtained;

[0085] (4) Add 0.5 g of USY molecular sieve (silicon to aluminum ratio = 30) to the solution obtained in step (3) and stir for 3 h;

[0086] (5) adding MCM-68 seed crystals to the solution obtained in step (4) and stirring to form a uniform solution, wherein 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;

[0087] (6) The solution obtained in step (5) was transferred to a hydrothermal reactor and hydrothermally crystallized at 170°C for 120 h. The obtained solid was centrifuged, washed, dried, and calcined at 550°C for 6 h to obtain UZM-35 molecular sieve, whose XRD spectrum is shown in FIG. Figure 3 . Samples in 2 θCharacteristic 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 impurity peaks, which means that pure phase UZM-35 molecular sieve is successfully prepared.

[0088] Example 4

[0089] MSE molecular sieve, UZM-35 molecular sieve, was synthesized using diethyldimethylammonium hydroxide as a structure-directing agent and USY molecular sieve (silicon-aluminum ratio (Si / Al) = 15, sourced from Tianjin Nanhua Catalyst Co., Ltd.) as the main aluminum and silicon sources. The steps are as follows:

[0090] (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.

[0091] (2) Add 0.443 g of Al(OH)3 to the solution obtained in step (1) and stir for 2 h;

[0092] (3) Add 12.721 g of silica sol (Ludox HS-40) to the solution obtained in step (2) and stir until a uniform gel state is obtained;

[0093] (4) Add 1 g of USY molecular sieve (silicon to aluminum ratio = 15) to the solution obtained in step (3) and stir for 3 h;

[0094] (5) adding MCM-68 seed crystals to the solution obtained in step (4) and stirring to form a uniform solution, wherein 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, and the mass of the MCM-68 seed crystals is 1.0% of the mass of SiO2;

[0095] (6) The solution obtained in step (5) was transferred to a hydrothermal reactor and hydrothermally crystallized at 170°C for 120 h. The obtained solid was centrifuged, washed, dried, and calcined at 550°C for 6 h to obtain UZM-35 molecular sieve, whose XRD spectrum is shown in FIG. Figure 4 . Samples in 2 θ 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 impurity peaks, which means that pure phase UZM-35 molecular sieve is successfully prepared.

[0096] Comparative Example 1

[0097] Preparation of UZM-35 molecular sieve (seed induction method) is as follows:

[0098] NaOH (96 wt%) and KOH were added to a 40 wt% aqueous solution of dimethyldiallylammonium hydroxide (structure directing agent, SDA), and then deionized water was added and stirred for 2 h to dissolve. Al(OH)3 was then added and stirred for 2 h, followed by silica sol (LudoxHS-40) and stirring for 2 h. MCM-68 seeds were then added and stirred for 5 h. The resulting gel was hydrothermally crystallized at 180 °C for 7 days (168 h). The molar composition ratio of the raw materials was 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 MCM-68 seed crystal is 10% of the mass of SiO2;

[0099] The crystallized product obtained by hydrothermal crystallization was washed and dried, and calcined at 550° C. for 6 h to obtain UZM-35 molecular sieve, which was labeled as UZM-35-SAC.

[0100] The XRD spectra of UZM-35 molecular sieves prepared by different synthetic routes in Example 1 and Comparative Example 1 are shown in FIG. Figure 5 ( Figure 5 RC represents relative crystallinity), SEM images are shown in Figure 6 , Figure 6 (a) is the SEM image of the UZM-35 molecular sieve obtained by the zeolite crystallization method in Example 1, and (b) is the SEM image of the UZM-35 molecular sieve obtained by the seed crystal induction method in Comparative Example 1. Figure 5 It can be seen that the relative crystallinity of the UZM-35 molecular sieve obtained by the zeolite crystallization method in Example 1 is 100%, and the crystal phase purity is high. The relative crystallinity of the UZM-35 molecular sieve obtained by the seed crystal induction method in Comparative Example 1 is 95%. Figure 6 It can be seen that the morphology of the UZM-35 molecular sieve obtained by the zeolite crystallization method in Example 1 presents a unique layered stacking structure, which is formed by mutually intersecting uniform lamellar units, with a particle size of 700~1300nm. The UZM-35 molecular sieve has a higher crystallinity, while the UZM-35 molecular sieve obtained by the seed induction method in Comparative Example 1 has more dispersed nanocrystals.

[0101] In Example 1, the zeolite-transformed crystal synthesis route used MCM-68 seed crystals at a rate of 1.0% by mass relative to the SiO2 mass, and the crystallization time was only four days. Compared to the seed-induced MSE synthesis route, the zeolite-transformed crystal synthesis route reduced the amount of MCM-68 seed crystals by over 95% by weight and shortened the crystallization time by over 40%, significantly reducing the synthesis cost and cycle time of UZM-35 molecular sieve.

[0102] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing UZM-35 molecular sieve, characterized in that: The following steps are involved: Sodium hydroxide, potassium hydroxide, a structure directing agent, water, an amorphous aluminum source, an amorphous silicon source, USY molecular sieve and MSE molecular sieve seed crystals are mixed to obtain a mixed solution; the structure directing agent is at least one of the following monoquaternary ammonium salt compounds: diethyldimethyl, dimethyldiallylethyl, dimethyldiallylbutyl, diethyldiallylethyl, diethyldiallyl, diethyldiallylbutyl; the amorphous aluminum source is converted to Al(OH)3, the amorphous silicon source is converted to SiO2, and the The USY molecular sieve is converted into Al(OH)3 and SiO2, and the molar ratio of the effective ingredients 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), the mass of the MSE molecular sieve seed crystal is 0.5~1.5% of the mass of SiO2; the MSE molecular sieve seed crystal is MCM-68 molecular sieve; The mixed solution is subjected to hydrothermal crystallization to obtain a crystallized product; the hydrothermal crystallization temperature is 150° C.; The crystallized product is calcined to obtain the UZM-35 molecular sieve.

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

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

4. The preparation method according to claim 1, characterized in that The amorphous silicon source is one or more of sodium silicate, silica sol and white carbon black.

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

6. The preparation method according to claim 1, characterized in that The mass of the MSE molecular sieve seed crystal is 1% of the mass of SiO2.

7. The preparation method according to any one of claims 1 to 6, characterized in that The mixing method is: mixing sodium hydroxide, potassium hydroxide, a structure directing agent and water to obtain a first mixed solution; performing a second mixing of the first mixed solution and an amorphous aluminum source to obtain a second mixed solution; performing a third mixing of the second mixed liquid and an amorphous silicon source to obtain a third mixed liquid; Mixing the third mixed solution with USY molecular sieve for the fourth time to obtain a fourth mixed solution; The fourth mixed liquid is mixed with MSE molecular sieve seed crystals for a fifth time to obtain the mixed liquid.

8. The preparation method according to claim 1, characterized in that The hydrothermal crystallization time is 96 to 168 hours.

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

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