Silicon-aluminum powder as well as preparation method and application thereof

Abstract

The invention relates to silicon-aluminum powder as well as a preparation method and application thereof. The silicon / aluminum atom molar ratio of the silicon-aluminum powder is not less than 1; the surface hydroxyl concentration of the silicon-aluminum powder is not less than 20 [mu] mol / g. The silicon-aluminum powder provided by the invention can be used for synthesis of a silicon-aluminum-containing crystal material, especially for efficient production of a beta molecular sieve, a ZSM-4 molecular sieve, a ZSM-5 molecular sieve, a ZSM-11 molecular sieve, a ZSM-12 molecular sieve, a ZSM-35 molecular sieve, an MCM-22 molecular sieve, an MCM-68 molecular sieve, an EU-1 molecular sieve, a mordenite molecular sieve, an SSZ-33 molecular sieve, an NU-87 molecular sieve, an IM-5 molecular sieve, an SSZ-39 molecular sieve, an SSZ-35 molecular sieve, a TNU-9 molecular sieve and the like. The effects of shortening the crystallization induction period and guiding the corresponding structure are achieved, and the efficiency of a seed crystal induction method or a guiding agent solution synthesis method is improved.

Description

Technical Field

[0001] The invention belongs to the field of silicon-aluminum powder materials, and specifically relates to silicon-aluminum powder and a preparation method thereof, as well as application of the silicon-aluminum powder to synthetic crystalline materials. Background Art

[0002] Zeolite molecular sieve is a type of crystalline catalytic material with molecular pores or cages formed by sharing the vertices of silicon, aluminum (or titanium, germanium, boron and other elements) tetrahedrons. It has functions such as ion exchange, shape-selective catalysis, and molecular sieving, and is widely used in the fields of oil refining, petrochemicals, and the synthesis of fine or special chemicals. In order to achieve the effective construction of long-range ordered silicon-containing crystalline materials, the main measure is to encourage more silicon atoms to enter the framework in an appropriate coordination form, which puts higher requirements on the silicon source. In the crystallization process of molecular sieves, the silicon source has a great influence on both kinetics and thermodynamics, and its dissolution activation is the rate-controlling step of crystallization; usually, liquid silica sol has poor activity and water glass easily induces the formation of impurity crystals (Studies in Surface Science & Catalysis, 1991, 65 (9): 603-612.). At the same time, for The catalytic activity of the carbon ion reaction with acid as the active center increases with the increase of the silicon-aluminum ratio of zeolite within a certain range; however, the thermodynamic process of sol-gel hydrothermal formation of ionic silicon clusters conforms to the LOWE equilibrium model, and the difficulty of effective activation (decomposition, crystallization and recombination) of the silicon source also increases with the increase of the silicon-aluminum ratio (Zeolites, 1983, 3(3):187-188).

[0003] Professor Wu Peng and others reported a reconstruction synthesis method (ZL2016108264030), which produced an active silicon source through a series of processes such as high-temperature roasting and deep acid hydrolysis. This method upgraded the effect of seed synthesis, but the process is relatively cumbersome and demanding, and the silicon obtained is not 100% pure. Organic structural directing agent (OSDA) can significantly reduce the barrier of molecular sieve silicon aluminum crystallization, and fill the pores to stabilize the structure, charge balance matching and other comprehensive effects; however, its large-scale use is limited by environmental pressure. Green synthesis is a new hot spot proposed in recent years. With the global attention to environmental protection, replacing or reducing the use of templates has become a common goal of researchers. Summary of the invention

[0004] In view of the above background, the purpose of the present invention is to solve the problem of poor crystallization activity of conventional silicon-aluminum raw materials in the prior art, and to provide a silicon-aluminum powder with a large surface hydroxyl concentration and a structural memory effect. The preparation method of the silicon-aluminum powder provided by the present invention highlights the hydrolysis and mineralization effect of the treatment agent on the silicon-aluminum species, forms rich surface hydroxyl species, obtains a uniformly mixed silicon-aluminum gel through a simple and controllable treatment method, obtains an intermediate powder through solvent recovery, and then obtains a solid silicon-aluminum powder with a structural memory effect through high-temperature calcination and purification; the obtained product can be identified by solid nuclear magnetic resonance, ultraviolet Raman spectroscopy (UV-Raman) and infrared spectroscopy and other characterization methods to identify the formation of structural units and surface hydroxyls.

[0005] For example, one of the purposes of the present invention is to provide a silicon aluminum powder that can be used in the synthesis of crystalline materials, and has the characteristics of easy activation and crystallization, low dependence on organic templates, and shortened crystallization induction period. Another purpose of the present invention is to provide a preparation method corresponding to the above silicon aluminum powder.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a silicon aluminum powder on the one hand, wherein the silicon / aluminum atomic molar ratio (silicon aluminum ratio) is not less than 1 (such as 1 to ∞), preferably 2 to 500; the surface hydroxyl concentration of the silicon aluminum powder is not less than 20 μmol / g, preferably not less than 30 μmol / g.

[0007] In some embodiments of the present invention, the surface hydroxyl concentration of the silicon aluminum powder is 20 to 60 μmol / g, preferably 30 to 60 μmol / g.

[0008] In some embodiments of the present invention, the silicon aluminum powder is measured by solid nuclear magnetic resonance aluminum spectroscopy. 27 In Al MAS NMR detection, the signal peak area of ​​hexacoordinated non-framework aluminum accounts for ≤50% of the total area of ​​all signal peaks, preferably ≤20%.

[0009] In the present invention, solid state NMR aluminum spectroscopy 27 The “total area of ​​all signal peaks” in the Al MAS NMR detection results refers to the sum of the signal peak area of ​​hexacoordinated non-framework aluminum and the signal peak area of ​​tetracoordinated framework aluminum.

[0010] In some embodiments of the present invention, the silicon aluminum powder is measured by solid nuclear magnetic resonance aluminum spectroscopy. 27 There are two types of characteristic signals in the Al MAS NMR detection, which are signal peaks near δ=0 and near δ=40-80.

[0011] In the present invention, the signal peak near δ=0 represents the hexacoordinated non-framework aluminum of the silicon aluminum powder, and the signal peak near δ=40-80 represents the tetracoordinated framework aluminum of the silicon aluminum powder.

[0012] In the present invention, by solid state nuclear magnetic resonance aluminum spectrum 27 The results of Al MAS NMR detection indicate that in the silicon-aluminum powder obtained by the present invention, more than 50% of the aluminum atoms in the composition form a framework four-coordinate structure.

[0013] In some embodiments of the present invention, the silicon aluminum powder is measured by solid state nuclear magnetic resonance silicon spectroscopy. 29 Si MAS NMR detection, the presence of Q 3 Coordination and Q 4 The characteristic signal of coordination, and Q 3 Coordination and Q 4 The ratio of the peak area of ​​the coordinated characteristic signal peak to the total area of ​​all signal peaks is ≥30%, preferably ≥60% (eg, 60-100%).

[0014] In the present invention, solid-state NMR silicon spectroscopy 29 The “total area of ​​all signal peaks” in Si MAS NMR test results refers to Q 1 The peak area of ​​the characteristic signal peak of coordination, Q 2 The peak area of ​​the characteristic signal peak of coordination, Q 3 The peak area and Q of the characteristic signal peak of coordination 4 The sum of the peak areas of the characteristic signal peaks of the coordination. 1 Coordination, Q 2 Coordination, Q 3 Coordination and Q 4 The difference in coordination lies in the number of -OH groups directly connected to Si. 1 Coordination refers to the direct connection between Si and 3 -OH groups, Q 2 Coordination refers to the direct connection between Si and two -OH groups, Q 3 Coordination refers to the direct connection between Si and one -OH group. 4 Coordination means that Si is not directly connected to -OH.

[0015] In the present invention, Q 3 The characteristic signal of coordination is around δ = -110 ~ -100, Q 4 The characteristic signal of coordination is around δ=-120~-110.

[0016] In the present invention, solid-state nuclear magnetic resonance silicon spectroscopy 29 The results of Si MAS NMR detection show that the corresponding proportion of Q 3 , Q 4 Coordination.

[0017] In some embodiments of the present invention, the silicon aluminum powder is detected by ultraviolet Raman spectroscopy at a vibration frequency of 240 cm -1There is a characteristic peak nearby; at the vibration frequency of 335cm -1 、400cm -1 or 480cm -1 There is at least one characteristic peak near the vibration frequency of 335cm -1 、400cm -1 or 480cm -1 There is at least one characteristic peak with a peak intensity greater than the vibration frequency 240cm -1 The peak intensity of the characteristic peaks near .

[0018] The present invention provides a silicon aluminum powder with a "structural memory effect". The silicon aluminum powder of the present invention is detected to have structural units such as four-membered rings, five-membered rings or six-membered rings by UV-Raman Raman spectroscopy structural characterization means, which is consistent with the TOT skeleton structural units in the synthesized molecular sieve and other silicon-containing crystalline materials. Therefore, the silicon aluminum powder of the present invention can be called a silicon aluminum powder with a structural memory effect.

[0019] According to the present invention, in the ultraviolet Raman spectrum of silicon aluminum powder, the vibration frequency is 240cm -1 The characteristic peaks near the 8-membered ring (8MR) represent the bending vibration signal of TOT in the silicon-containing 8-membered ring (TOT bending vibration). -1 In the characteristic region of the structural unit, the smaller rings correspond to higher vibration frequencies, not 240 cm -1 Among the characteristic peaks nearby, 335cm -1 、400cm -1 and 480cm -1 The characteristic peaks near the ring represent the bending vibration of TOT in the six-membered ring (6MR), five-membered ring (5MR) and four-membered ring (4MR) containing silicon, respectively. -1 、400cm -1 or 480cm -1 The presence of at least one characteristic peak nearby indicates the presence of at least one structural unit of 6MR, 5MR or 4MR. Vibration frequency 335cm -1 、400cm -1 or 480cm -1 The peak intensity of the characteristic peak near the vibration frequency is greater than 240cm -1 The peak intensity of the characteristic peak near φ indicates that the number of 6MR, 5MR or 4MR structural units in the silicon-aluminum powder is greater than the number of 8MR structural units.

[0020] As for the expression "near" in the above content, those skilled in the art will know that each characteristic peak (signal peak) usually has a displacement, so the position of the characteristic peak defined in the present invention may have deviations.-1 The nearby characteristic peak is at 450cm -1 ~500cm -1 However, the deviation represented by each characteristic peak (signal peak) can be determined by those skilled in the art.

[0021] In some embodiments of the present invention, the specific surface area of ​​the silicon aluminum powder is 500m 2 / g~1200m 2 / g.

[0022] In some embodiments of the present invention, the pore volume of the silicon aluminum powder is 0.05 cm 3 / g~5cm 3 / g.

[0023] The second aspect of the present invention provides a method for preparing the silicon aluminum powder described in the first aspect, comprising the following steps:

[0024] S1, providing a mixed solution I containing a treatment reagent I and a solvent I; the treatment reagent I comprises a halogen-containing compound, preferably at least one selected from silicon tetrafluoride, silicon tetrachloride, ammonium fluoride, ammonium chloride, ammonium bromide, ammonium iodide, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, hydrofluoric acid, hydrochloric acid and hydrobromic acid;

[0025] Providing a mixed solution II containing a treatment reagent II and a solvent II; the treatment reagent II includes an acidic reagent, preferably at least one selected from ammonium nitrate, nitric acid, ammonium fluoride, ammonium chloride, hydrochloric acid, ammonium bromide, perbromic acid, carbonic acid, acetic acid, phosphoric acid, oxalic acid, formic acid, acetic acid, citric acid, ammonium iodide, iodine-containing acid, hydrofluoric acid and hydrobromic acid;

[0026] S2, performing a first mixing process on the silicon-containing raw material and the mixed solution I to obtain a mixed solution III;

[0027] Performing a second mixing process on the aluminum-containing raw material and the mixed solution II to obtain a mixed solution IV;

[0028] S3, after mixing the mixed solution III with the mixed solution IV, sequentially subjecting the mixed solution to a standing treatment, a de-impurity treatment and a calcination treatment to obtain the silicon-aluminum powder.

[0029] In some embodiments of the present invention, a small amount of alkaline substance may be added to the mixed solution I to further promote the activation of the silicon-containing raw material.

[0030] In some embodiments of the present invention, in step S1, the solvent I and the solvent II are the same or different, and are independently selected from at least one of water, alcohols and ionic liquids; preferably selected from at least one of deionized water, methanol, ethanol, isopropanol, n-butanol, ethylene glycol, 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6).

[0031] In some embodiments of the present invention, in step S2, the silicon-containing raw material is selected from at least one of silicates (such as tetramethyl silicate TMOS, tetraethyl silicate TEOS or tetrapropyl silicate TPOS), isobutylene triethoxysilane, tetramethylsilane (Si(CH3)4, silicon tetrachloride, methyltrimethoxysilane (MTMS), trichlorosilane (SiHCl3), hexamethyldisilazane and hexamethyldisiloxane.

[0032] In some embodiments of the present invention, the aluminum-containing raw material is selected from at least one of aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum hydrogen phosphate, aluminum sol, pseudo-boehmite, alumina powder prepared by alcohol aluminum process, boehmite, α-alumina, β-alumina, γ-alumina and θ-alumina.

[0033] In some embodiments of the present invention, the molar ratio of the treatment reagent I to SiO2 in the silicon-containing raw material (hereinafter referred to as the treatment reagent I / SiO2 molar ratio) is 0.0001 to 2:1, preferably 0.001 to 0.2:1.

[0034] In some embodiments of the present invention, the molar ratio of the solvent I to SiO2 in the silicon-containing raw material is 0.5 to 100:1 (hereinafter referred to as the solvent I / SiO2 molar ratio) is 0.5 to 100:1, preferably 1 to 10:1.

[0035] In some embodiments of the present invention, the mass ratio of the treatment reagent II to Al2O3 in the aluminum-containing raw material is 0.0001 to 2:1, preferably 0.001 to 0.25:1.

[0036] In some embodiments of the present invention, in the aluminum-containing mixed solution II, the mass fraction of Al2O3 is 0.1% to 60%, preferably 1% to 31%.

[0037] In some embodiments of the present invention, the conditions for the first mixing treatment include: a stirring speed of 0 to 5000 rpm, preferably 2 to 100 rpm; a temperature of 0 to 50° C., preferably 5 to 30° C. The mixing treatment time is 1 s to 10 h.

[0038] In some embodiments of the present invention, the conditions for the second mixing process include: a stirring speed of 0 to 5000 rpm, preferably 2 to 100 rpm; a temperature of 0 to 50° C., preferably 5 to 30° C. The mixing process is performed for 1 second to 10 hours.

[0039] In some embodiments of the present invention, in step S3, the conditions for the static treatment include: a temperature of -30 to 50°C; and / or a time of 10 to 2000 min. The static treatment is completed by sealed curing at -30 to 50°C for 10 to 2000 min.

[0040] In some embodiments of the present invention, the temperature of the impurity removal treatment is 20-100° C. The solvent and volatile substances are removed at 20-100° C. The impurity removal treatment method includes an oven, a muffle furnace / mesh belt kiln, an infrared lamp, irradiation, vacuum filtration, natural light exposure, etc.

[0041] In some embodiments of the present invention, the calcination treatment conditions include: a temperature of 200 to 1200° C.; and a time of 0.1 to 100 h.

[0042] In some embodiments of the present invention, the calcination conditions include: in the temperature range of 250 to 1100° C., at least two calcination temperatures are selected from low to high in an air atmosphere for 0.01 to 2 h, preferably 0.1 to 2 h.

[0043] In some embodiments of the present invention, the calcination conditions include: performing the calcination at 250-350°C, 350-500°C, and 500-1100°C for 0.01-2h, preferably 0.1-2h.

[0044] In the present invention, the calcination treatment is used to remove the skeleton crystal water (the desorption temperature is usually ≥ 200°C at normal pressure), sublimable fluoride, sulfur or MoO x It can also completely decompose organic matter by high-temperature oxidation.

[0045] In some embodiments of the present invention, in step S3, after the mixed liquid III is mixed with the mixed liquid IV, a sol-gel is obtained, and the sol-gel is then subjected to a standing treatment and a decontamination treatment (removal of solvent and volatile substances) until a solid block is precipitated, and the solid is powdered to obtain an intermediate powder; the intermediate powder is calcined to obtain the silicon-aluminum powder.

[0046] The preparation method of silicon aluminum powder of the present invention selects silane-based silicon-rich substances and aluminum-containing substances as initial raw materials, and uses halogen-containing compounds and acidic reagents as treating agents respectively, so as to highlight the hydrolysis and mineralization of silicon species, form rich surface silanol species, and form aluminum-containing substances with H+ The protons represented by are acted on alumina, and through a simple and controllable treatment method, the solvent is recovered and the gel is obtained, which is then purified by high-temperature calcination to obtain solid silicon-aluminum powder with structural memory effect.

[0047] The third aspect of the present invention provides an application of the silicon aluminum powder as described in the first aspect or the silicon aluminum powder prepared by the preparation method as described in the second aspect in preparing crystalline materials.

[0048] In the present invention, the crystalline material refers to silicon-aluminum microporous zeolite molecular sieve, silicon-phosphorus-aluminum molecular sieve, borosilicate molecular sieve, titanium-silicon molecular sieve, pure silicon porous material and the like.

[0049] According to the present invention, after the silicon-aluminum powder is used to synthesize the crystalline material, the crystalline material (catalytic material) can be used in a highly efficient catalytic carbonium ion reaction.

[0050] In some embodiments of the present invention, the crystalline material is at least one of β molecular sieve, ZSM-4 molecular sieve, ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-12 molecular sieve, ZSM-35 molecular sieve, MCM-22 molecular sieve, MCM-68 molecular sieve, EU-1 molecular sieve, mordenite molecular sieve, SSZ-33 molecular sieve, NU-87 molecular sieve, IM-5 molecular sieve, SSZ-39 molecular sieve, SSZ-35 molecular sieve, and TNU-9 molecular sieve.

[0051] In some embodiments of the present invention, the silicon aluminum powder selected when synthesizing ZSM-5 molecular sieve, mordenite, β molecular sieve, EU-1, SSZ-33 or MCM-22 (rich five-membered ring molecular sieve) is 400cm -1 preferably, at 400cm -1 The characteristic peaks nearby are the main characteristic peaks (with the largest peak area).

[0052] In some embodiments of the present invention, the silicon aluminum powder selected when synthesizing β molecular sieve, ZSM-4, ZSM-12, NU-87, etc. (molecular sieves marked by the formation of a four-membered ring structure during the induction period) is 480 cm -1 preferably, at 480cm -1 The characteristic peaks nearby are the main characteristic peaks (with the highest peak intensity).

[0053] In the present invention, when preparing synthetic crystal materials (such as molecular sieves), the synthesis methods of crystalline materials of different configurations are different, and the silicon aluminum powder of the present invention can be applied. As for the amount of silicon aluminum powder, those skilled in the art can add an appropriate amount according to different requirements of the target product.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) The silicon-aluminum powder provided by the present invention has a large concentration of surface active hydroxyl groups and a high structure-directed activity, which can solve the problem of poor crystallization activity of conventional silicon-aluminum raw materials; and the silicon-aluminum powder helps to shorten the induction period when acting on synthetic crystalline materials;

[0056] (2) The preparation method of silicon-aluminum powder provided by the present invention selects silane-based silicon-rich substances and aluminum-containing substances as initial raw materials, respectively, and uses halogen-containing compounds and acidic reagents as treating agents, respectively, to highlight the hydrolysis and mineralization of silicon species, to form rich surface silanol species, and to form H + The protons represented by are acted on alumina, and a mixed gel is obtained through a controllable process, and an intermediate powder is formed after the solvent is recovered, and then the silicon aluminum powder is purified by high-temperature roasting; the preparation method of the present invention avoids the use of excessive solvents and the generation of waste water, and the process route can be used for industrial efficient production, which provides the possibility for its application in a wider field of efficient synthesis of crystal catalytic materials with silicon aluminum as the main skeleton composition;

[0057] (3) The silicon-aluminum powder with a structural memory effect of the present invention can be used for the synthesis of crystalline materials with silicon-aluminum as the main skeleton composition, especially for the efficient production of β molecular sieve, ZSM-4 molecular sieve, ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-12 molecular sieve, ZSM-35 molecular sieve, MCM-22 molecular sieve, MCM-68 molecular sieve, EU-1 molecular sieve, mordenite molecular sieve, SSZ-33 molecular sieve, NU-87 molecular sieve, IM-5 molecular sieve, SSZ-39 molecular sieve, SSZ-35 molecular sieve, TNU-9 molecular sieve, etc., which plays a role in shortening the crystallization induction period and the corresponding structure guidance, saving the time required for synthesis, and improving the efficiency of the seed induction method or the guiding agent solution synthesis method. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0059] Figure 1 The Fourier transform infrared spectra of the silicon aluminum powder SAJ01 prepared in Example 1 of the present invention and the sample DBJ01 prepared in Comparative Example 1 in the hydroxyl region are shown;

[0060] Figure 2 The skeleton Fourier transform infrared spectrum of the silicon aluminum powder SAJ01 prepared in Example 1 of the present invention is shown;

[0061] Figure 3 The scanning electron microscope (SEM) image of the silicon aluminum powder SAJ01 prepared in Example 1 of the present invention is shown;

[0062] Figure 4The solid magic angle aluminum nuclear magnetic resonance spectrum of the silicon aluminum powder SAJ01 prepared in Example 1 of the present invention is shown ( 27 AlMAS NMR);

[0063] Figure 5 The solid magic angle aluminum nuclear magnetic resonance spectrum of the sample DBJ01 prepared in Comparative Example 1 of the present invention is shown ( 27 Al MASNMR);

[0064] Figure 6 The solid magic angle silicon nuclear magnetic resonance spectrum of the silicon aluminum powder SAJ01 prepared in Example 1 of the present invention is shown ( 29 SiMAS NMR);

[0065] Figure 7 The low temperature nitrogen adsorption-desorption curves of the silicon aluminum powders SAJ01 and SAJ02 prepared in Examples 1 and 2 of the present invention are shown;

[0066] Figure 8 The UV-Raman spectra of the silicon aluminum powder SAJ01 prepared in Example 1 of the present invention and the sample DBJ01 prepared in Comparative Example 1 at 244 nm of ultraviolet excitation light are shown;

[0067] Fig. 9 The UV-Raman spectrum of EU-1 molecular sieve synthesized using silicon aluminum powder SAJ01 in Example 43 of the present invention is shown;

[0068] Fig.10 The UV-Raman spectrum of the beta molecular sieve synthesized using silicon aluminum powder SAJ02 in Example 44 of the present invention is shown. DETAILED DESCRIPTION

[0069] In order to make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments and drawings. These embodiments are only for illustration and are not intended to limit the application scope of the present invention.

[0070] In the present invention, the surface hydroxyl concentration of the silicon aluminum powder is measured by analyzing the hydroxyl region of the molecular sieve using a Nexus 670 Fourier transform infrared spectrometer (FT-IR) produced by Nicolet Company of the United States. For the test of the hydroxyl vibration region of the molecular sieve, 50 mg of the molecular sieve sample powder is pressed into a thin sheet with a diameter of 1 cm, placed in a vacuum cell, and vacuumed and dehydrated at 450° C. for 1.5 hours, and then tested after the temperature is lowered to room temperature.

[0071] The Fourier transform infrared spectrum of the skeleton vibration area was also analyzed and tested using the Nexus 670 Fourier transform infrared spectrometer (FT-IR) produced by Nicolet Company in the United States, with a test resolution of 4 cm -1, scanning times 32 times, test range 400~4000cm -1 ; Dilute the sample powder with KBr to a mass fraction of about 3%, grind and mix evenly with a mortar, press into tablets, and scan;

[0072] The crystal morphology was observed using a Nova Nano SEM 450 field emission scanning electron microscope produced by FEI Company with an operating voltage of 2.0 kV.

[0073] Solid-state magic angle NMR spectroscopy was performed using a Bruker Avance III / WB-400 spectrometer. 29 Si MAS NMR and 27 Al MAS NMR test, 27 Al MAS NMR test standard KAl(SO4)2.12H2O, rotation speed 12kHz, resonance frequency 79.50MHz, relaxation time 4s; 29 Si MAS NMR Test Standard Q8M8([(CH3)3SiO]8SiO 12 ), rotation speed 3kHz, resonance frequency 79.43MHz, relaxation time 60s.

[0074] The specific surface area and pore volume were analyzed by low-temperature N2 adsorption-desorption analysis of the samples using a Tristar3000 specific surface analyzer produced by Micrometrics. The samples were pretreated at 300°C for 6 hours by vacuum activation before testing. The test temperature was -196°C. The pore structure data such as specific surface area and pore volume of the test samples were obtained by analyzing the isotherms.

[0075] The molecular sieve samples were analyzed by Raman spectroscopy using a Jobin-Yvon T6400 triplet ultraviolet-Raman spectrometer (UV-Raman) developed by the Dalian Institute of Physical Chemistry with a resolution of 2 cm -1 , the excitation light source wavelength is 244nm.

[0076] The dry basis mass fraction of silicon aluminum powder was measured by thermogravimetric TG-DTA analysis of the sample using TGA Q500analyzer instrument (test conditions were air atmosphere, heating rate 10°C / min).

[0077] In the following examples, all chemical reagents used are commercially available products and, unless otherwise specified, have not been specially purified.

[0078] Example 1

[0079] Weigh 0.1g of sodium hydroxide and 0.4g of sodium fluoride, add them into 200ml of deionized water, stir and mix until dissolved evenly, then add 500g of methanol and place in a constant temperature water bath at 10°C; under stirring at 30rpm, take 520g of tetramethyl silicate (TMOS) and add it to the above solution, stir evenly; wherein the molar ratio of the treatment reagent I / SiO2 is 0.0026; the molar ratio of the solvent I / SiO2 is 7.3.

[0080] A certain amount of pseudo-boehmite was weighed according to the Si / Al atomic molar ratio of 35, and slurried with water to obtain a slurry with an Al2O3 mass content of 16%. Under stirring conditions of 25°C and 30rpm, hydrochloric acid was added at a hydrochloric acid / Al2O3 mass ratio of 0.05 and stirred evenly.

[0081] The aluminum liquid was quickly added to the silicon-containing material and mixed evenly, and then placed in a container in a constant temperature water bath at 10°C for 2 hours to obtain a sol-gel. The solvent methanol and water were evaporated in a vacuum at 55°C until a solid block was precipitated, and then the solid was taken out and powdered to obtain an intermediate powder. The temperature was then raised to 550°C at 3°C / min, and the intermediate powder was calcined at a constant temperature for 3 hours to obtain sample SAJ01.

[0082] The surface hydroxyl concentration of sample SAJ01 is 39 μmol / g silicon aluminum powder, and the specific surface area is S BET =620m 2 / g, pore volume = 0.55cm 3 / g.

[0083] Figure 1 In the FT-IR spectrum, 3580-3600, 3680-3700 and 3720-3730 cm -1 The characteristic vibration peaks nearby correspond to the bridge hydroxyl group, internal hydroxyl group and terminal hydroxyl group (external hydroxyl group), and the areas of the above characteristic peaks of the SAJ01 sample are larger, indicating that its hydroxyl group distribution is richer.

[0084] Figure 8 In the UV-Raman spectrum, the vibration frequency is less than 600cm -1 The structural unit characteristic area of ​​DBJ01 is only amorphous TOT at 240 cm -1 As the TOT bond angle decreases and the force constant increases, the active Al atoms activate and ionize the Si-O bonds, increase the skeleton flexibility and reduce the skeleton stress. The SAJ01 sample has a peak at 335cm -1 , especially 400cm -1 and 480cm -1 Signal peaks belonging to specific structural units appeared near the positions of 335cm -1 、400cm -1and 480cm -1 The characteristic peaks near the surface overlap partially. It can be seen that the vibration frequency is around 335cm -1 、400cm -1 and 480cm -1 The peak area of ​​the characteristic peak near 240 cm -1 The peak area of ​​the characteristic peak nearby.

[0085] Figure 2 In the FT-IR spectrum of sample SAJ01, the -1 The vibration peaks nearby correspond to silanols species.

[0086] Depend on Figure 3 From the scanning electron microscope photograph, it can be seen that the nanoparticles of sample SAJ01 are uniform in size and highly dispersed.

[0087] Depend on Figure 4 It can be seen that sample SAJ01 shows tetracoordinated framework aluminum (δ>50), and there is no obvious characteristic peak attributable to hexacoordinated non-framework aluminum at δ=0, indicating that more than 50% of the aluminum atoms in sample SAJ01 form framework tetracoordinates.

[0088] Depend on Figure 6 It can be seen that the sample SAJ01 has Q corresponding to (SiO)4Si species and (SiO)3Si(1Al) near the chemical shifts -115 and -111, respectively. 4 The strong signal vibration peak of the structural species; the broadened NMR vibration peak signal of the sample at -104 is attributed to the (SiO)3Si(OH) species in the molecular sieve (Q 3 ), indicating that there are a certain amount of coordination defect (SiO)3Si(OH) species, and there are no obvious silicon species with other coordination numbers.

[0089] Comparative Example 1

[0090] Weigh white carbon black and pseudo-boehmite, and stir them mechanically to make them uniform; wherein the Si / Al atomic molar ratio is 35.

[0091] The obtained silicon and aluminum oxides form a powder mixture, and the comparative sample is marked as DBJ01.

[0092] Figure 1 In the FT-IR spectrum, 3580-3600, 3680-3700 and 3720-3730 cm -1 The characteristic vibration peaks nearby correspond to the bridge hydroxyl group, internal hydroxyl group and terminal hydroxyl group (external hydroxyl group), respectively. The above characteristic peak areas of DBJ01 sample are all small, indicating that its surface hydroxyl distribution is not as rich as that of SAJ01.

[0093] Depend on Figure 5 It can be seen that sample DBJ01 has an obvious characteristic peak attributable to hexacoordinated non-framework aluminum near δ=0, indicating that in this sample, the framework coordination of aluminum atoms mainly comes from the mechanical mixing composition of pseudo-boehmite, which is dominated by amorphous hexacoordinated non-framework aluminum.

[0094] Figure 8 In the UV-Raman spectrum, the vibration frequency is less than 600cm -1 The structural unit characteristic area of ​​DBJ01 is only amorphous TOT at 240 cm -1 characteristic peaks.

[0095] Using the sample of this comparative example as the synthetic raw material of the molecular sieve is not conducive to the formation of molecular sieve supercages or 10-membered ring and 12-membered ring microporous channels, and is likely to lead to the formation of dense phase small-pore zeolite impurities. At the same time, the crystallinity of the product will be significantly lower than the crystallinity of the product synthesized using SAJ01 as the raw material under the same synthetic conditions.

[0096] Comparative Example 2

[0097] A certain amount of pseudo-boehmite and tetramethyl silicate (TMOS) were weighed according to the Si / Al atomic molar ratio of 35.

[0098] Pseudo-boehmite was slurried with water to obtain a slurry with an Al2O3 mass content of 16%. Under stirring conditions of 25°C and 30 rpm, hydrochloric acid was added at a hydrochloric acid / Al2O3 mass ratio of 0.05 and stirred evenly.

[0099] The aluminum liquid was quickly added to tetramethyl silicate (TMOS) and mixed evenly, and then placed in a container in a constant temperature water bath at 10°C for 2 hours to obtain a sol-gel, and the solvent methanol and water were evaporated in a vacuum at 55°C until a solid block was precipitated, and then the intermediate powder was obtained by powdering. The temperature was then raised to 550°C at a rate of 3°C / min, and the intermediate powder was calcined at a constant temperature for 3 hours to obtain the sample DBJ02.

[0100] The characteristic vibration peak areas of sample DBJ02 in the FT-IR spectrum are smaller than those of sample SAJ01. 29 Si MAS NMR solid state nuclear magnetic resonance test results show that Q 4 The vibration signal peak of the structural species is significantly weaker than that of the SAJ01 sample. In the UV-Raman spectrum, the amorphous TOT in the DBJ02 sample is at 240 cm -1 The characteristic peaks of the SAJ01 sample are significantly stronger than those of the SAJ01 sample.

[0101] Using the sample of this comparative example as the synthetic raw material of the molecular sieve is not conducive to the formation of molecular sieve supercages or 10-membered ring and 12-membered ring microporous channels, and is likely to lead to the formation of dense phase small-pore zeolite impurities. At the same time, the crystallinity of the product will be significantly lower than the crystallinity of the product synthesized using SAJ01 as the raw material under the same synthetic conditions.

[0102] Comparative Example 3

[0103] Weigh 0.1g of sodium hydroxide and 0.4g of sodium fluoride, add them to 200ml of deionized water, stir and mix until dissolved evenly, then add 500g of methanol and place in a constant temperature water bath at 10°C; under stirring at 30rpm, take 520g of tetramethyl silicate (TMOS) and add it to the above solution, stir evenly; wherein the molar ratio of the treatment reagent I / SiO2 is 0.0026; the molar ratio of the solvent I / SiO2 is 7.3.

[0104] A certain amount of pseudo-boehmite was weighed according to the Si / Al atomic molar ratio of 35, and slurried with water to obtain a slurry with an Al2O3 mass content of 16%.

[0105] The aluminum liquid was quickly added to the silicon-containing material and mixed evenly, and then placed in a container in a constant temperature water bath at 10°C for 2 hours to obtain a sol-gel. The solvent methanol and water were evaporated in a vacuum at 55°C until a solid block was precipitated, and then the solid was taken out and powdered to obtain an intermediate powder. The temperature was then raised to 550°C at a rate of 3°C / min, and the intermediate powder was calcined at a constant temperature for 3 hours to obtain sample DBJ03.

[0106] The characteristic vibration peak areas in the FT-IR spectrum of sample DBJ03 are smaller than those of sample SAJ01. 27 The results of Al MAS NMR solid state nuclear magnetic resonance test show that the characteristic peak of hexacoordinated non-framework aluminum in DBJ03 sample near δ = 0 is significantly stronger than that in SAJ01 sample. At the same time, the amorphous TOT in DBJ03 sample in UV-Raman spectrum is at 240 cm -1 The characteristic peaks of the SAJ01 sample are significantly stronger than those of the SAJ01 sample.

[0107] Using the sample of this comparative example as the synthetic raw material of the molecular sieve is not conducive to the formation of molecular sieve supercages or 10-membered ring and 12-membered ring microporous channels, and is likely to lead to the formation of dense phase small-pore zeolite impurities. At the same time, the crystallinity of the product will be significantly lower than the crystallinity of the product synthesized using SAJ01 as the raw material under the same synthetic conditions.

[0108] Comparative Example 4

[0109] Weigh 0.1 g of sodium hydroxide and add it to 200 ml of deionized water. After mixing and stirring to dissolve evenly, add 500 g of methanol and place in a constant temperature water bath at 10°C. Under stirring at 30 rpm, take 520 g of tetramethyl silicate (TMOS) and add it to the above solution and stir evenly.

[0110] A certain amount of pseudo-boehmite was weighed according to the Si / Al atomic molar ratio of 35. The pseudo-boehmite was slurried with water to obtain a slurry with a mass content of 16% Al2O3.

[0111] The aluminum liquid is quickly added to the silicon-containing material and mixed evenly. After precipitation is obtained, it is transferred to a container and placed in a constant temperature water bath at 10°C for 2 hours. Under stirring conditions of 30rpm, 0.4g of sodium fluoride is first added and stirred evenly, and then hydrochloric acid is added and stirred evenly. The mass ratio of hydrochloric acid / Al2O3 is 0.05. The solvent methanol and water are vacuum evaporated at 55°C until a solid block is precipitated, and the powder is taken out to obtain an intermediate powder. Then the temperature is raised to 550°C at 3°C / min, and the intermediate powder is constant temperature roasted for 3 hours to obtain sample DBJ04.

[0112] The characteristic vibration peak area in the FT-IR spectrum of sample DBJ04 is significantly smaller than that of sample SAJ01. 27 The Al MAS NMR solid state nuclear magnetic resonance test results show that the DBJ04 sample has an obvious characteristic peak belonging to hexacoordinated non-framework aluminum near δ = 0, which is significantly stronger than that of the SAJ01 sample. 29 Si MAS NMR solid state nuclear magnetic resonance test results show that the Q 4 The vibration signal peak of the structural species is obviously weaker than that of the SAJ01 sample. In addition, the amorphous TOT in the DBJ04 sample has a peak at 240 cm -1 The characteristic peaks of the SAJ01 sample are significantly stronger than those of the SAJ01 sample.

[0113] Using the sample of this comparative example as the synthetic raw material of the molecular sieve is not conducive to the formation of molecular sieve supercages or 10-membered ring and 12-membered ring microporous channels, and is likely to lead to the formation of dense phase small-pore zeolite impurities. At the same time, the crystallinity of the product will be significantly lower than the crystallinity of the product synthesized using SAJ01 as the raw material under the same synthetic conditions.

[0114] Example 2

[0115] Weigh 0.2 g of sodium fluoride, add it to 180 ml of deionized water, mix and stir until dissolved evenly, then add 460 g of isopropanol, and place in a constant temperature water bath at 25°C; under stirring at 12 rpm, take 485 g of hexamethyldisilazane and add it to the above solution, stir evenly, wherein the molar ratio of the treatment reagent I / SiO2 is 0.0008; the molar ratio of the solvent I / SiO2 is 2.94.

[0116] A certain amount of aluminum sulfate was weighed according to the Si / Al atomic molar ratio of 4, and dissolved in water to obtain a solution with a 20% Al2O3 mass content. NH4F was added at a NH4F / Al2O3 mass ratio of 0.005 at 25°C and 30 rpm stirring conditions and stirred evenly;

[0117] The aluminum liquid was quickly added to the silicon-containing material and mixed evenly. The mixture was placed in a 30°C constant temperature water bath in a container and allowed to stand for 0.5 h to obtain a sol-gel. The solvent isopropanol and water were evaporated under vacuum at 70°C until a solid block was precipitated. The solid was taken out and powdered to obtain an intermediate powder. The temperature was then raised to 450°C at a rate of 1.5°C / min, and the intermediate powder was calcined at a constant temperature for 8 h. Sample SAJ02 was obtained.

[0118] After testing, the surface hydroxyl concentration of the sample is 26μmol / g silicon aluminum powder, and the specific surface area is S BET =550m 2 / g, pore volume = 1.05cm 3 / g, UV-Raman detected its vibration frequency at 335cm -1 、400cm -1 and 480cm -1 The peak areas of the characteristic peaks near 240 cm -1 The peak area of ​​the characteristic peak nearby.

[0119] Figure 7 The low-temperature nitrogen adsorption-desorption curves of the silicon aluminum powders SAJ01 and SAJ02 prepared in Examples 1 and 2 of the present invention are exemplarily shown, and the pore structure data such as the BET specific surface area and pore volume of the test samples are obtained by analyzing the isotherms.

[0120] Example 3-12

[0121] The preparation methods of Examples 3 to 12 are basically the same as those of Example 1, except for the selection of different silicon-containing raw materials, aluminum-containing raw materials, treatment reagents and solvent I. The specific preparation conditions are shown in Table 1 below. The samples are marked as SAJ03 to SAJ12 in sequence, and the performance parameter information of the samples is shown in Table 2 below.

[0122]

[0123]

[0124]

[0125] Examples 13-22

[0126] The preparation methods of Examples 13 to 22 are basically the same as those of Example 2, except for the selection of different treatment reagent I / SiO2 molar ratios, solvent I / SiO2 molar ratios, treatment reagent II / Al2O3 mass ratios and the mass fraction of Al2O3 in the aluminum-containing mixed solution. The specific preparation conditions are shown in Table 3 below. The samples are marked as SAJ13 to SAJ22 in sequence, and the performance parameter information of the samples is shown in Table 4 below.

[0127]

[0128]

[0129]

[0130] Examples 23-32

[0131] Examples 23 to 32 are basically the same as Examples 13 to 22 (i.e., Example 23 follows Example 13, Example 24 follows Example 14, and so on), except that the calcination activation conditions are different. The specific preparation conditions are shown in Table 5. The obtained samples are marked as SAJ23 to SAJ32, and the performance parameter information of the samples is shown in Table 6 below.

[0132]

[0133]

[0134]

[0135] Examples 33-42

[0136] Examples 33 to 42 are: samples SAJ3 to SAJ12 obtained in Examples 3 to 12 are used respectively to synthesize β molecular sieves according to the following β molecular sieve synthesis method to obtain β molecular sieve samples SAJ33-SAJ42.

[0137] The relevant parameters of samples SAJ33-SAJ42 are shown in Table 7 below. According to the crystallization kinetics curve, the induction period time results of the above samples SAJ33-SAJ42 at 85°C were measured, and the results are shown in Table 7 below.

[0138] The synthesis method of β molecular sieve is as follows:

[0139] Measure 1200 ml of deionized water, dissolve 55 g of sodium hydroxide and 2500 g of 35 wt% tetraethylammonium hydroxide (template) aqueous solution. Weigh 1400 g of silicon aluminum powder SAJ33-SAJ42, and evenly add it into the above solution to obtain a gel solution.

[0140] The gel solution was transferred into a pressure bomb lined with tetrafluoroethylene, pre-crystallized at 90°C for 4 hours, hydrothermally synthesized at 165°C for 4 days, naturally cooled to below 40°C in air, filtered and washed, and dried at 120°C for 12 hours to obtain a solid product.

[0141]

[0142]

[0143] From Table 7, the UV-Raman detection of the above-mentioned β molecular sieve samples SAJ33-SAJ42 and samples SAJ3-SAJ12 shows that their vibration frequency is 335cm -1 、400cm -1 or 480cm -1 There are characteristic signal peaks nearby, indicating that there is a good structural memory effect between the molecular sieve product and the silicon aluminum powder raw material.

[0144] Embodiment 43

[0145] A method for synthesizing EU-1 molecular sieve is provided, which is as follows:

[0146] 56 g of the silicon aluminum powder SAJ01 of Example 1 was dissolved in 120 g of deionized water. Under stirring at a rate of 120 rpm, 100 g of a 25 wt% aqueous solution of hexamethylammonium hydroxide HM(OH)2 was added. A 22% mass fraction of sodium hydroxide aqueous solution was used to adjust the pH value to 11.8 to obtain an initial gel. The gel was aged at 20°C for 30 min. The initial gel was then transferred to a stainless steel reaction tank and sealed. After pre-crystallization at a hydrothermal temperature of 120°C for 2 h, the gel was taken out and re-crystallized at a hydrothermal temperature of 180°C for 48 h to obtain a crystallized product. The crystallized product was cooled, filtered, washed and dried to obtain a final solid product.

[0147] In the above, the molar ratio of the template, silicon source, aluminum source, alkali source and solvent is (1-20): (10-180): 1: (0-60): (50-900); the final solid product obtained is EU-1 molecular sieve SAJ43.

[0148] It can be seen from the crystallization kinetics curve that the crystallization induction period of the molecular sieve synthesis of this embodiment is 24h. Tetramethyl silicate (TMOS) is used as the silicon source, pseudo-boehmite is used as the aluminum source, the Si / Al atomic molar ratio is 35, and the molecular sieve is synthesized using the same synthesis process as this embodiment. The crystallization induction period of this comparative synthesis process is 72h. It can be seen that the silicon aluminum powder provided by the present invention can significantly shorten the crystallization induction period.

[0149] Depend on Fig. 9It can be seen that the UV-Raman spectrum of the obtained product EU-1 molecular sieve SAJ43 shows that its vibration frequency is 335cm -1 and 400cm -1 The characteristic peaks are obviously higher, and there is a good structural memory effect between the molecular sieve and silicon aluminum powder.

[0150] Embodiment 44

[0151] A method for synthesizing a beta molecular sieve is provided, which is as follows:

[0152] 1200 ml of deionized water was measured to dissolve 55 g of sodium hydroxide and 2500 g of 35 wt% tetraethylammonium hydroxide (template) aqueous solution. 1400 g of the silicon-aluminum powder SAJ02 obtained in Example 2 was weighed and evenly added to the above solution to obtain a gel solution.

[0153] The gel solution was transferred into a pressure bomb lined with tetrafluoroethylene. It was first pre-crystallized at 90°C for 4 hours, then hydrothermally synthesized at a crystallization temperature of 165°C for 4 days, naturally cooled to below 40°C in air, filtered and washed, and dried at 120°C for 12 hours to obtain a solid product, β molecular sieve SAJ44.

[0154] It can be seen from the crystallization kinetics curve that the crystallization induction period of the molecular sieve synthesis of this embodiment is 30h. Hexamethyldisilazane is used as the silicon source, aluminum sulfate is used as the aluminum source, the Si / Al atomic molar ratio is 4, and the molecular sieve is synthesized using the same synthesis process as this embodiment. The crystallization induction period of this comparative synthesis process is 96h. It can be seen that the silicon aluminum powder provided by the present invention can significantly shorten the crystallization induction period.

[0155] Depend on Fig.10 It can be seen that the UV-Raman spectrum of the obtained product β molecular sieve JS44 shows that its vibration frequency is detected at 335cm -1 、400cm -1 and 480cm -1 The characteristic peak signal nearby is obvious, and there is a good structural memory effect between the molecular sieve and the silicon source (silicon aluminum powder SAJ2).

[0156] Comparative Example 5

[0157] The molecular sieve synthesis method refers to Example 43, with the only difference being that 56 g of the silicon aluminum powder SAJ01 of Example 1 is replaced by 56 g of the sample DBJ01 of the comparative example.

[0158] The test results are as follows: The product synthesized with DBJ01 as the raw material is a low-crystallinity EU-1 molecular sieve containing a large amount of ANA impurities. Compared with the crystallinity of the product synthesized with SAJ01 as the raw material under the same synthesis conditions, the crystallinity of the product is greatly reduced, and the crystallization induction period is greater than 60 hours. In the UV-Raman spectrum of the product, the vibration frequency is 335cm -1 and 400cm -1 The characteristic peak is weak.

[0159] Comparative Example 6

[0160] The molecular sieve synthesis method refers to Example 43, with the only difference being that 56 g of the silicon aluminum powder SAJ01 of Example 1 is replaced by 56 g of the sample DBJ02 of the comparative example.

[0161] The test results are as follows: The product synthesized with DBJ02 as the raw material is a low-crystallinity EU-1 molecular sieve. Compared with the crystallinity of the product synthesized with SAJ01 as the raw material under the same synthesis conditions, the crystallinity of the product is greatly reduced, the crystallization induction period is greater than 60 hours, and there are small-pore molecular sieve impurities of ANA configuration in the product. In the UV-Raman spectrum of the product, the vibration frequency is 335cm -1 and 400cm -1 The characteristic peak is weak.

[0162] Comparative Example 7

[0163] The molecular sieve synthesis method refers to Example 43, with the only difference being that 56 g of the silicon aluminum powder SAJ01 of Example 1 is replaced by 56 g of the sample DBJ03 of the comparative example.

[0164] The test results are as follows: The product synthesized with DBJ03 as the raw material is a low-crystallinity EU-1 molecular sieve. Compared with the crystallinity of the product synthesized with SAJ01 as the raw material under the same synthesis conditions, the crystallinity of the product is greatly reduced, the crystallization induction period is greater than 60 hours, and there are small-pore molecular sieve impurities of ANA configuration in the product. In the UV-Raman spectrum of the product, the vibration frequency is 335cm -1 and 400cm -1 The characteristic peak is weak.

[0165] Comparative Example 8

[0166] The molecular sieve synthesis method refers to Example 43, with the only difference being that 56 g of the silicon aluminum powder SAJ01 of Example 1 is replaced by 56 g of the sample DBJ04 of the comparative example.

[0167] The test results are as follows: The product synthesized with DBJ04 as the raw material is a low-crystallinity EU-1 molecular sieve containing a large amount of ANA impurities. Compared with the crystallinity of the product synthesized with SAJ01 as the raw material under the same synthesis conditions, the crystallinity of the product is greatly reduced, and the crystallization induction period is greater than 60 hours. In the UV-Raman spectrum of the product, the vibration frequency is 335cm -1 and 400cm -1 The characteristic peak is weak.

[0168] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A silicon aluminum powder, wherein the silicon / aluminum atomic molar ratio is not less than 1, preferably 2 to 500; the surface hydroxyl concentration of the silicon aluminum powder is not less than 20 μmol / g, preferably not less than 30 μmol / g.

2. The silicon aluminum powder according to claim 1, characterized in that The silicon aluminum powder is measured by solid nuclear magnetic resonance aluminum spectrum 27 In AlMAS NMR detection, the signal peak area of ​​hexacoordinated non-framework aluminum accounts for ≤50% of the total area of ​​all signal peaks, preferably ≤20%; And / or, the silicon aluminum powder is measured by solid nuclear magnetic resonance silicon spectroscopy 29 Si MAS NMR detection, the presence of Q 3 and Q 4 The characteristic signal of coordination, and Q 3 Coordination and Q 4 The ratio of the peak area of ​​the coordinated characteristic signal peak to the total area of ​​all signal peaks is ≥30%, preferably ≥60%.

3. The silicon aluminum powder according to claim 1, characterized in that The silicon aluminum powder was detected by ultraviolet Raman spectroscopy at a vibration frequency of 240 cm -1 There is a characteristic peak nearby; at the vibration frequency 335cm -1 、400cm -1 or 480cm -1 There is at least one characteristic peak near the vibration frequency of 335cm -1 、400cm -1 or 480cm -1 There is at least one characteristic peak with a peak intensity greater than the vibration frequency 240cm -1 The peak intensity of the characteristic peaks near .

4. The silicon aluminum powder according to any one of claims 1 to 3, characterized in that The specific surface area of ​​the silicon aluminum powder is 500m 2 / g~1200m 2 / g; And / or, the pore volume of the silicon aluminum powder is 0.05cm 3 / g~5cm 3 / g.

5. A method for preparing silicon aluminum powder as claimed in any one of claims 1 to 4, comprising the following steps: S1, providing a mixed solution I containing a treatment reagent I and a solvent I; the treatment reagent I comprises a halogen-containing compound, preferably at least one selected from silicon tetrafluoride, silicon tetrachloride, ammonium fluoride, ammonium chloride, ammonium bromide, ammonium iodide, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, hydrofluoric acid, hydrochloric acid and hydrobromic acid; Providing a mixed solution II containing a treatment reagent II and a solvent II; the treatment reagent II includes an acidic reagent, preferably at least one selected from ammonium nitrate, nitric acid, ammonium fluoride, ammonium chloride, hydrochloric acid, ammonium bromide, perbromic acid, carbonic acid, acetic acid, phosphoric acid, oxalic acid, formic acid, acetic acid, citric acid, ammonium iodide, iodine-containing acid, hydrofluoric acid and hydrobromic acid; S2, performing a first mixing process on the silicon-containing raw material and the mixed solution I to obtain a mixed solution III; Performing a second mixing process on the aluminum-containing raw material and the mixed solution II to obtain a mixed solution IV; S3, after mixing the mixed solution III with the mixed solution IV, sequentially subjecting the mixed solution to a standing treatment, a de-impurity treatment and a calcination treatment to obtain the silicon-aluminum powder.

6. The preparation method according to claim 5, characterized in that: In step S1, the solvent I and the solvent II are the same or different, and are independently selected from at least one of water, alcohols and ionic liquids; preferably selected from at least one of deionized water, methanol, ethanol, isopropanol, n-butanol, ethylene glycol, 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate; And / or, in step S2, the silicon-containing raw material is selected from at least one of silicate, isobutylene triethoxysilane, tetramethylsilane, silicon tetrachloride, methyltrimethoxysilane, trichlorosilane, hexamethyldisilazane and hexamethyldisilchloroethane; And / or, in step S2, the aluminum-containing raw material is selected from at least one of aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum hydrogen phosphate, aluminum sol, pseudo-boehmite, alumina powder prepared by alcohol aluminum process, boehmite, α-alumina, β-alumina, γ-alumina and θ-alumina.

7. The preparation method according to claim 5 or 6, characterized in that: The molar ratio of the treatment reagent I to SiO2 in the silicon-containing raw material is 0.0001 to 2:1; and / or, the molar ratio of the solvent I to SiO2 in the silicon-containing raw material is 0.5 to 100:1; and / or, the mass ratio of the treatment reagent II to Al2O3 in the aluminum-containing raw material is 0.0001 to 2:1, preferably 0.001 to 0.25:1; And / or, in the aluminum-containing mixed solution II, the mass fraction of Al2O3 is 0.1% to 60%, preferably 1% to 31%.

8. The preparation method according to any one of claims 5 to 7, characterized in that: In step S3, The conditions for the static treatment include: a temperature of -30 to 50°C; And / or, the temperature of the de-doping treatment is 20 to 100°C; And / or, the conditions for the calcination treatment include: a temperature of 200-1200°C; preferably, within the temperature range of 250-1100°C, at least two calcination temperatures are selected from low to high in an air atmosphere for calcination; preferably, the calcination treatment is carried out at a temperature of 250-350°C, a temperature of 350-500°C, and a temperature of 500-1100°C, respectively.

9. Use of the silicon-aluminum powder according to any one of claims 1 to 4 or the silicon-aluminum powder prepared by the preparation method according to any one of claims 5 to 8 in preparing crystalline materials.

10. The use according to claim 9, characterized in that: The crystalline material is at least one of β molecular sieve, ZSM-4 molecular sieve, ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-12 molecular sieve, ZSM-35 molecular sieve, MCM-22 molecular sieve, MCM-68 molecular sieve, EU-1 molecular sieve, mordenite molecular sieve, SSZ-33 molecular sieve, NU-87 molecular sieve, IM-5 molecular sieve, SSZ-39 molecular sieve, SSZ-35 molecular sieve, and TNU-9 molecular sieve.

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