SCM-38 molecular sieve and its preparation method

Abstract

The present invention discloses an SCM-38 molecular sieve and a preparation method thereof. The SCM-38 molecular sieve is a new type of molecular sieve, and its chemical composition includes, in molar ratio: SiO2: Al2O3: P2O5 = 0-0.1: 0.8-1.5: 1, and the XRD pattern of the SCM-38 molecular sieve includes X-ray diffraction peaks at 2θ of 7.20 ± 0.1, 10.81 ± 0.1, 11.60 ± 0.1, 14.32 ± 0.1, 21.39 ± 0.1, 21.83 ± 0.1, 27.31 ± 0.1, and 28.72 ± 0.1, wherein 2θ is 7.20 ± 0.1 as the strongest peak. The SCM-38 molecular sieve provided by the present invention can be used in adsorbents or catalysts.

Description

Technical Field

[0001] The present invention belongs to the field of molecular sieves, and in particular relates to a novel molecular sieve, namely SCM-38 molecular sieve, and a preparation method thereof. Background Art

[0002] Molecular sieves are a class of porous crystalline materials widely used in chemical industries such as oil refining and catalysis. Different pore structures reflect different macroscopic properties such as adsorption and catalysis, and molecular sieves with different structures have been synthesized. Currently, over 250 types of molecular sieves with known structures have been discovered (including partially disordered ones). Because molecular sieves have uniform, regular pores whose pore sizes are on the same order of magnitude as small organic molecules, they can "screen" molecules entering the sieve according to their spatial size during chemical reactions, thereby achieving a certain degree of selective adsorption and catalytic shape selectivity. The molecular sieve framework is typically composed of coordination tetrahedra (TO4) connected by common vertices (usually oxygen atoms). In conventional zeolite molecular sieves, the tetrahedra in the framework are primarily silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra. These two types of tetrahedra can also be replaced by other tetrahedra, forming molecular sieves with a variety of framework structures or compositions.

[0003] In 1971, Flanigen et al. reported the synthesis of aluminum phosphate molecular sieves (Molecular Sieve Zeolites-I, ACS, Washington DC), which can be understood as the formation of molecular sieves by replacing the silicon-oxygen tetrahedrons in the zeolite molecular sieves with phosphorus-oxygen tetrahedrons. The skeleton of this type of molecular sieve is formed by AlO4 - and PO4 +The molecular sieve framework is electrically neutral due to the presence of shared oxygen atoms. Similar to zeolite molecular sieves, the aluminum oxide tetrahedrons or phosphorus oxide tetrahedrons in aluminum phosphate molecular sieves can be replaced by other tetrahedrons, the most common of which are silicon oxide tetrahedrons and zinc oxide tetrahedrons. The introduction of these tetrahedrons gives aluminum phosphate molecular sieves new properties. Compared to zeolite molecular sieves, the artificial synthesis of aluminum phosphate molecular sieves was relatively recent. Under hydrothermal synthesis conditions, mixing aluminum, silicon, and phosphorus oxides yielded aluminum-silicon-phosphorus molecular sieves with the same crystal structure as analcime, chabazite, phillipsite-harmotome, L-type molecular sieve, A-type molecular sieve, and B-type molecular sieves, with phosphorus contents ranging from 5% to 25% (as P2O5). However, no molecular sieves with structures different from known zeolite molecular sieves were found. U.S. Patent No. 4,310,440 of 1982 used organic amines or quaternary ammonium compounds as templates to hydrothermally synthesize a series of aluminum phosphate molecular sieves, including AlPO4-5, AlPO4-8, AlPO4-9, AlPO4-11, AlPO4-12, AlPO4-14, AlPO4-16, AlPO4-17, AlPO4-18, AlPO4-20, AlPO4-21, AlPO4-22, AlPO4-23, AlPO4-25, AlPO4-26, AlPO4-28, AlPO4-31, etc. With the continuous deepening of the understanding of factors such as molecular sieve structure, performance, synthesis method, and conditions, and the continuous advancement of synthesis technology, molecular sieves with new structures are constantly being synthesized. For the synthesis of aluminum phosphate molecular sieves, the type of organic template is one of the key factors determining its structure. So far, organic amines remain the most widely used templates in the synthesis of aluminum phosphate molecular sieves. Compared to silica-alumina zeolites, the industrial application of aluminophosphate molecular sieves is relatively rare. Currently, only a few molecular sieves have achieved practical industrial application, such as SAPO-34 and SAPO-11. Science, 2016, 351, 1065-1068, revealed that SAPO molecular sieves have achieved good catalytic performance as part of a coupled catalyst in the synthesis gas to olefins reaction.Su et al. (Su, J., Zhou, H., Liu, S. et al. Syngas to light olefins conversion with high olefin / paraffinratio using ZnCrOx / AlPO-18bifunctional catalysts. Nat Commun 10, 1297 (2019).) revealed that the bifunctional catalyst prepared by phosphate-aluminum molecular sieve and metal oxide has outstanding performance in the direct conversion of synthesis gas to olefins with a high olefin-paraffin ratio. From the above, it can be seen that aluminum phosphate molecular sieve has great industrial application potential.

[0004] Since different pore structures and elemental compositions determine the unique physicochemical and catalytic properties of molecular sieves, the development of new structural molecular sieves is particularly important. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a new type of molecular sieve not involved in the prior art, namely SCM-38 molecular sieve and a preparation method thereof.

[0006] To solve the above technical problems, the first aspect of the present invention provides an SCM-38 molecular sieve, the chemical composition of the SCM-38 molecular sieve including, by molar ratio: SiO2:Al2O3:P2O5=0-0.1:0.8-1.5:1, the XRD spectrum of the SCM-38 molecular sieve includes X-ray diffraction peaks at 2θ of 7.20±0.1, 10.81±0.1, 11.60±0.1, 14.32±0.1, 21.39±0.1, 21.83±0.1, 27.31±0.1, and 28.72±0.1, wherein the strongest peak is at 2θ of 7.20±0.1.

[0007] Furthermore, preferably, the XRD pattern of the SCM-38 molecular sieve comprises the X-ray diffraction peaks shown in the following table:

[0008] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.20±0.1 100 10.81±0.1 5-50 11.60±0.1 5-50 14.32±0.1 5-50 21.39±0.1 5-50 21.83±0.1 5-50 27.31±0.1 5-50 28.72±0.1 5-50 .

[0009] Furthermore, the chemical composition of the SCM-38 molecular sieve includes, by molar ratio: Al2O3:P2O5=0.8-1.5:1, including but not limited to 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1 and the like; by molar ratio: SiO2:P2O5=0-0.1:1, including but not limited to 0.01:1, 0.03:1, 0.05:1, 0.07:1, 0.09:1, 0.1:1 and the like.

[0010] A second aspect of the present invention provides a method for preparing the above-mentioned SCM-38 molecular sieve, comprising:

[0011] a) mixing an aluminophosphate precursor, an organic base R1, an organic substance R2, a fluorine source, water, an optional aluminum source A, and an optional silicon source to obtain a synthesis mother solution;

[0012] b) liquid crystallizing the synthetic mother liquid described in step a) to obtain SCM-38 molecular sieve;

[0013] Wherein, the organic base R1 is one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, etc.; the organic compound R2 is one or more of N,N,N,'N'-tetramethylhexanediamine, triethylamine, or cyclohexylamine, etc.;

[0014] The aluminophosphate precursor has a chemical composition as shown in the formula "Al2O3:xP2O5", wherein 0.8≤x≤2; the XRD spectrum of the aluminophosphate precursor mainly includes the X-ray diffraction peaks shown in the following table:

[0015] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.59±0.2 100 10.81±0.1 5-50 16.52±0.1 5-50 17.97±0.1 5-50 23.34±0.05 5-50 34.74±0.05 5-50 .

[0016] Furthermore, the XRD pattern of the aluminophosphate precursor also includes the X-ray diffraction peaks shown in the following table:

[0017] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 14.25±0.1 5-50 21.01±0.1 10-20 24.27±0.05 5-50 26.05±0.05 5-50 27.82±0.05 5-50 28.15±0.02 5-50 30.03±0.02 5-50 .

[0018] Furthermore, the XRD pattern of the aluminophosphate precursor also includes the X-ray diffraction peaks shown in the following table:

[0019]

[0020]

[0021] In the above technical solution, the molar ratio of each material in the synthesis mother liquor is as follows: silicon source (as SiO2), aluminum source A (as Al2O3), aluminophosphate precursor (as Al2O3 and P2O5), organic base R1, organic compound R2, fluorine source (as HF), and water (as H2O): (0-0.1) SiO2: (0.88-1.3) Al2O3: 1 P2O5: (0.3-0.8) R1: (1-2) R2: (0.5-1.8) HF: (50-130) H2O. The amount of aluminum source A is determined by the amount of Al2O3 in the aluminophosphate precursor. That is, when the amount of Al2O3 provided by the aluminophosphate precursor meets the above ratio requirements, aluminum source A is not added. When the amount of Al2O3 provided by the aluminophosphate precursor does not meet the above ratio requirements, aluminum source A is added to meet the above ratio requirements.

[0022] In the above technical solution, the aluminum source A is selected from one or more of pseudo-boehmite, aluminum isopropoxide, aluminum sol, aluminum oxide, etc.

[0023] In the above technical solution, the silicon source is selected from one or more of silica sol, fumed silica, etc.

[0024] In the above technical solution, the fluorine source is selected from HF aqueous solution.

[0025] In the above technical solution, in step a), the order of adding the materials is not particularly limited. Preferably, water, optional aluminum source A, optional silicon source and phosphate aluminate precursor are first mixed evenly, and then organic matter R2 and organic base R1 are added in sequence and mixed evenly, and then the fluorine source is added.

[0026] In the above technical solution, in step b), the crystallization conditions are as follows: the crystallization temperature of the first stage is 120°C-165°C, and the crystallization time is 24-84 hours; preferably, the crystallization temperature is 120°C-160°C, and the crystallization time is 36-80 hours; the crystallization temperature of the second stage is 170°C-200°C, and the crystallization time is 2-24 hours; preferably, the crystallization temperature is 180°C-200°C, and the crystallization time is 4-18 hours.

[0027] In the above technical solution, in step b), after the crystallization step is completed, the SCM-38 molecular sieve product can be separated from the obtained mixture by any conventional separation method, such as separation, washing and drying. Here, the separation, washing and drying can be carried out in any conventional manner known in the art, wherein separation is such as centrifugation or filtration, suction filtration. The drying temperature can be selected from 40-120°C, preferably 50-80°C; the drying time can be 8-48 hours, preferably 12-24 hours. The drying can be carried out under normal pressure or under reduced pressure. In order to save energy, normal pressure is often selected.

[0028] The third aspect of the present invention provides a molecular sieve composition, comprising the SCM-38 molecular sieve according to any of the aforementioned aspects or the SCM-38 molecular sieve prepared according to the method described in any of the aforementioned aspects, and a binder.

[0029] The fourth aspect of the present invention provides an application of a molecular sieve, the application of the SCM-38 molecular sieve according to any of the preceding aspects, the SCM-38 molecular sieve prepared according to the method described in any of the preceding aspects, or the SCM-38 molecular sieve composition according to any of the preceding aspects in an adsorbent or catalyst.

[0030] In the above technical solution, the SCM-38 molecular sieve or molecular sieve composition is used as an adsorbent, for example, to separate at least one component from a mixture of multiple components in a gas or liquid phase. Accordingly, the at least one component can be partially or substantially completely separated from the mixture of various components, for example, by contacting the mixture with the SCM-38 molecular sieve or molecular sieve composition to selectively adsorb the component.

[0031] In the above technical solution, the SCM-38 molecular sieve or molecular sieve composition can be used as a catalyst for organic matter conversion.

[0032] The SCM-38 molecular sieve of the present invention is a new type of molecular sieve, which has a unique XRD diffraction pattern and enriches the types of molecular sieves. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is the XRD pattern of the aluminophosphate precursor A obtained in Example 1;

[0034] Figure 2 This is the XRD pattern of the aluminophosphate precursor B obtained in Example 2;

[0035] Figure 3 The XRD pattern of the SCM-38 molecular sieve obtained in Example 3;

[0036] Figure 4 This is a SEM image of the SCM-38 molecular sieve obtained in Example 3;

[0037] Figure 5 This is the XRD pattern of the SCM-38 molecular sieve obtained in Example 10;

[0038] Figure 6 This is the XRD pattern of the SCM-38 molecular sieve obtained in Example 11;

[0039] Figure 7 This is the XRD pattern of the SCM-38 molecular sieve obtained in Example 12;

[0040] Figure 8 This is the XRD pattern of the SCM-38 molecular sieve obtained in Example 13;

[0041] Figure 9 The XRD pattern of the product obtained in Comparative Example 1;

[0042] Figure 10 The XRD pattern of the product obtained in Comparative Example 2;

[0043] Figure 11 The XRD pattern of the product obtained in Comparative Example 3 is shown in FIG. DETAILED DESCRIPTION

[0044] The specific embodiments of the present invention are described in detail below, but the protection scope of the present invention is not limited by these specific embodiments.

[0045] In the present invention, the structure of the molecular sieve is determined by an X-ray diffraction spectrum (XRD), and the X-ray diffraction spectrum (XRD) of the molecular sieve is measured by an X'Pert PRO X-ray powder diffraction (XRD) instrument of PANalytical, the Netherlands, using a Cu-Kα ray source, with a Kα1 wavelength of λ = 1.5405980 angstroms ( ), nickel filter, working voltage 40kV, current 40mA, scanning range 3-50°.

[0046] In the present invention, the compositions of SiO2, Al2O3 and P2O5 in the molecular sieve are measured by ICP method. The element ratios in the sample are analyzed by Varian Analytical 725-ES inductively coupled plasma emission spectrometer (Varian Analytical, USA).

[0047] The aluminophosphate precursor of the present invention has a schematic chemical composition as shown in the formula "Al2O3:xP2O5", wherein 0.8≤x≤2; the XRD pattern of the aluminophosphate precursor includes the X-ray diffraction peaks shown in the following table:

[0048]

[0049]

[0050] Furthermore, the XRD pattern of the aluminophosphate precursor also includes the X-ray diffraction peaks shown in the following table:

[0051] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 14.25±0.1 5-50 21.01±0.1 10-20 24.27±0.05 5-50 26.05±0.05 5-50 27.82±0.05 5-50 28.15±0.02 5-50 30.03±0.02 5-50 .

[0052] Furthermore, the XRD pattern of the aluminophosphate precursor also includes the X-ray diffraction peaks shown in the following table:

[0053] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 12.09±0.1 5-50 19.77±0.1 5-50 31.33±0.01 5-50 38.29±0.01 5-50 .

[0054] Furthermore, the preparation method of the aluminophosphate precursor of the present invention comprises: A and organic template R B , a mixture of solvent S1, solvent S2 and solvent S3 is crystallized to obtain an aluminophosphate precursor;

[0055] Wherein, the organic template R A One or more selected from quaternary ammonium salts or quaternary ammonium bases; R B One or more selected from imidazole or pyrrolidine derivatives; solvent S1 is selected from one or more amide solvents; solvent S2 is selected from one or more cyclic organic solvents; S3 is selected from one or more water or low-carbon alcohols.

[0056] Furthermore, in the preparation method of the aluminophosphate precursor, the organic template R A One or more selected from tetraethylammonium bromide, tetraethylammonium hydroxide, tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetrabutylammonium bromide, and tetrabutylammonium hydroxide; the organic template R B One or more selected from imidazole, 2-methylimidazole, 4-methylimidazole, 1-(3-aminopropyl)imidazole, 2-ethyl-4-methylimidazole, pyrrolidine, 1-(3-pyrrolidine)pyrrolidine, N-ethyl-2-aminomethylpyrrolidine; the solvent S1 is one or more selected from N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide and N,N-dibutylformamide; the solvent S2 is one or more selected from 1,4-dioxane, cyclohexane, cyclohexanone and; the solvent S3 is one or more selected from methanol, ethanol, ethylene glycol, butanol, cyclohexanol and water.

[0057] Furthermore, in the preparation method of the aluminophosphate precursor, the organic template R A Preferably, one or more of tetraethylammonium bromide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide are used; the organic template R B Preferably, it is one or more of 1-(3-aminopropyl)imidazole, 2-ethyl-4-methylimidazole, and N-ethyl-2-aminomethylpyrrolidine; the solvent S1 is preferably one or more of N,N-dimethylacetamide and N,N-dibutylformamide; the solvent S2 is preferably one or both of 1,4-dioxane and cyclohexanone; the solvent S3 is preferably one or both of ethanol and water, and deionized water is more preferred.

[0058] Furthermore, in the preparation method of the aluminophosphate precursor, in the mixture, the aluminum source B is calculated as Al2O3, the phosphorus source is calculated as P2O5, and the organic template R A +R B , the molar composition of the solvent S1+S2+S3 is as follows: P2O5 / Al2O3=0.75-2.2, preferably 1-2; the template R A +R B / Al2O3=1-80, preferably 5-50; solvent S1+S2+S3 / Al2O3=5-500, preferably 35-120.

[0059] Furthermore, in the preparation method of the aluminophosphate precursor, the organic template R A With organic template R B The molar ratio is 0.01-1:1, preferably 0.1-0.25:1.

[0060] Furthermore, in the method for preparing the aluminophosphate precursor, the molar ratio of the solvent S1, the solvent S2, and the solvent S3 is 1:0.01-1:1-100, preferably 1:0.05-0.5:10-80.

[0061] Furthermore, in the preparation method of the aluminophosphate precursor, the aluminum source B is selected from one or more of aluminum isopropoxide, aluminates, metaaluminates, aluminum salts, aluminum hydroxides, aluminum oxides and aluminum-containing minerals, preferably one or two of aluminates and metaaluminates; the phosphorus source is selected from at least one of phosphoric acid, ammonium monohydrogen phosphate and ammonium dihydrogen phosphate, preferably orthophosphoric acid.

[0062] Furthermore, in the method for preparing the aluminophosphate precursor, stirring and settling treatments are performed before crystallization treatment, wherein the stirring time is 0.5-5 hours, and the settling time is 1-12 hours.

[0063] Furthermore, in the preparation method of the aluminophosphate precursor, the crystallization treatment conditions include: a crystallization temperature of 120-200°C, preferably 140-180°C, more preferably 140-160°C; and a crystallization time of 1-5d, preferably 3-5d, more preferably 4-5d.

[0064] Furthermore, in the method for preparing the aluminophosphate precursor, the crystallization treatment is followed by conventional post-treatment, such as filtration, washing, and drying to obtain the molecular sieve. The filtration, washing, and drying can be performed in any manner conventionally known in the art, wherein separation may be performed by centrifugation, filtration, or suction filtration. The drying temperature may be 40-120°C, preferably 50-80°C; the drying time may be 8-48 hours, preferably 12-24 hours. The drying may be performed under normal pressure or under reduced pressure. To save energy, normal pressure is often selected.

[0065] The technical solution of the present invention is described in detail below with reference to the embodiments.

[0066] [Example 1]

[0067] 38 g of aluminum nitrate [Al(NO3)3·9H2O] was dissolved in 43 mL of deionized water, and 25.2 g of phosphoric acid (purity ≥85 wt%), 151 g of tetrabutylammonium hydroxide (40 wt% aqueous solution) and 145.6 g of 1-(3-aminopropyl)imidazole were added under stirring. The mixture was stirred for 0.5 h and precipitated for 12 h to obtain solution A. Then, 16 mL of N, N-dibutylformamide and 4.6 mL of cyclohexanone were added to solution A. After stirring for 3.5 h, the mixture was heat-treated at 90 ° C for 8 h to form a uniform crystallized mixture B, wherein the molar ratio of the aluminum source calculated as Al2O3, the phosphorus source calculated as P2O5, the total template and the total solvent is: Al2O3: P2O5: template R: solvent S = 1:2.1:7:40, template R A (Tetrabutylammonium hydroxide): Template R B (1-(3-aminopropyl)imidazole) = 0.2 (molar ratio), solvent S1 (N,N-dibutylformamide): solvent S2 (cyclohexanone): solvent S3 (water) = 1:0.5:78.5 (molar ratio); the above crystallization mixture B was placed in a crystallization kettle with a tetrafluoroethylene lining and crystallized at 140°C for 5 days. The product was filtered, washed, and dried at 80°C for 24 hours to obtain a phosphate aluminate precursor, denoted as A, for future use. Among them, in the phosphate aluminate precursor A, Al2O3:P2O5=1:2. The XRD pattern of the phosphate aluminate precursor A is shown in Figure 1 , that is, including the X-ray diffraction peaks shown in Table 1:

[0068] Table 1

[0069]

[0070]

[0071] [Example 2]

[0072] 33.3 g of aluminum sulfate [Al2(SO4)3·18H2O] was dissolved in 66.3 mL of water, and 5.2 g of phosphoric acid (purity ≥85 wt%), 117.0 g of tetrabutylammonium hydroxide (40 wt% aqueous solution) and 102.6 g of 1-(3-aminopropyl)imidazole were added under stirring to obtain a mixed solution. The solution was stirred for 3 h and precipitated for 6 h to obtain solution A. Then, 255 mL of N, N-dibutylformamide and 48 mL of cyclohexanone were added to the mixture A, stirred for 4.5 h, and then heat-treated at 80°C for 12 h to form a uniform mixture B, wherein the molar ratio of the aluminum source calculated as Al2O3, the phosphorus source calculated as P2O5, the template and the solvent is: Al2O3: P2O5: total template R: total solvent S = 1:0.9:10:80, template R A (Tetrabutylammonium hydroxide): Template R B (1-(3-aminopropyl)imidazole) = 0.22 (molar ratio), solvent S1 (N,N-dibutylformamide): solvent S2 (cyclohexanone): solvent S3 (water) = 1:0.3:48 (molar ratio); the above mixture B was placed in a crystallization reactor with a tetrafluoroethylene line and crystallized at 140°C for 5 days. The product was filtered, washed, and dried at 80°C for 24 hours to obtain an aluminum phosphate precursor, denoted as B, for future use. Among them, in the aluminum phosphate precursor B, Al2O3:P2O5=1:0.92. The XRD pattern of the aluminum phosphate precursor B is shown in Figure 2 , namely including the X-ray diffraction peaks shown in Table 2:

[0073] Table 2

[0074]

[0075]

[0076] [Example 3]

[0077] Weigh 24g of water, add 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor A, and stir at room temperature for 3h. Then add 1.6g of triethylamine, and then add 4.4g of 25wt% tetraethylammonium hydroxide solution. After stirring at room temperature for 3h, add 1g of 40wt% HF solution, stir evenly, and place in a tetrafluoroethylene-lined autoclave. Crystallize at 140℃ for 60h, then at 180℃ for 18h. After cooling, centrifuge, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=1.25:1 in molar ratio. The XRD pattern of SCM-38 molecular sieve is shown in Figure 1. Figure 3 , i.e. including the main X-ray diffraction peaks shown in Table 3, the SEM image of the obtained SCM-38 molecular sieve is shown in Figure 4 :

[0078] Table 3

[0079] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.20 100 10.81 15 11.60 7 14.32 19 21.39 11 21.83 22 27.31 10 28.72 24

[0080] [Example 4]

[0081] Weigh 12g of water, add 2.48g of pseudo-boehmite and 6g of aluminophosphate precursor A, and stir at room temperature for 3h. Then add 1.6g of triethylamine, followed by 4.4g of 25wt% tetraethylammonium hydroxide solution. Stir at room temperature for 3h, then add 0.43g of 40wt% HF solution, stir evenly, and place in a tetrafluoroethylene-lined autoclave. Crystallize at 140°C for 66h; then raise the temperature to 180°C and crystallize at this temperature for 8h. After cooling, centrifuge, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=0.98:1 in molar ratio. The XRD spectrum of SCM-38 molecular sieve includes the main X-ray diffraction peaks shown in Table 4:

[0082] Table 4

[0083] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.19 100 10.80 18 11.59 9 14.33 20 21.39 12 21.82 23 27.30 12 28.68 26

[0084] [Example 5]

[0085] Weigh 24g of water, 3.7g of aluminum isopropoxide and 6g of aluminophosphate precursor A and stir at room temperature for 3h; then add 2.4g of triethylamine and then 4.4g of 25wt% tetraethylammonium hydroxide solution. After stirring at room temperature for 2h, add 1g of 40wt% HF solution, stir evenly and place in a tetrafluoroethylene-lined autoclave. Crystallize at 140℃ for 60h; then raise the temperature to 180℃ and crystallize at this temperature for 8h. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition, in terms of molar ratio, is Al2O3:P2O5=1.1:1. The XRD spectrum of SCM-38 molecular sieve includes the main X-ray diffraction peaks shown in Table 5:

[0086] Table 5

[0087]

[0088]

[0089] [Example 6]

[0090] Weigh 24g of water, 4.3g of aluminum isopropoxide, and 6g of aluminophosphate precursor A, and stir at room temperature for 3h. Then add 1.6g of triethylamine, followed by 6.6g of 25wt% tetraethylammonium hydroxide solution. After stirring at room temperature for 3h, add 1g of 40wt% HF solution, stir evenly, and place in a tetrafluoroethylene-lined autoclave. Crystallize at 140°C for 66 hours; then raise the temperature to 180°C and crystallize at this temperature for 12 hours. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=1.02:1 in molar ratio. The XRD spectrum of SCM-38 molecular sieve includes the main X-ray diffraction peaks shown in Table 6:

[0091] Table 6

[0092] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.21 100 10.83 28 11.59 16 14.32 22 21.38 12 21.85 21 27.28 12 28.74 20

[0093] [Example 7]

[0094] Weigh 28g of water, 4.65g of aluminum isopropoxide, and 6g of aluminophosphate precursor A, and stir at room temperature for 3h. Then add 2.7g of triethylamine, followed by 4.4g of 25wt% tetraethylammonium hydroxide solution. After stirring at room temperature for 3h, add 1.3g of 40wt% HF solution, stir evenly, and place in a tetrafluoroethylene-lined autoclave. Crystallize at 140°C for 36 hours; then raise the temperature to 180°C and crystallize at this temperature for 16 hours. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=0.96:1 in molar ratio. The XRD spectrum of SCM-38 molecular sieve includes the main X-ray diffraction peaks shown in Table 7:

[0095] Table 7

[0096] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.19 100 10.82 22 11.58 8 14.34 19 21.38 8 21.82 18 27.35 11 28.71 23

[0097] [Example 8]

[0098] Weigh 28g of water, 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor A, stir at room temperature for 3h; then add 1.6g of triethylamine, followed by 2.73g of 25wt% tetramethylammonium hydroxide solution, stir at room temperature for 3h, then add 1g of 40wt% HF solution, stir evenly and place in a tetrafluoroethylene-lined autoclave. Crystallize at 160℃ for 48h; then raise the temperature to 180℃ and crystallize at this temperature for 8h. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=1.05:1 in molar ratio. The XRD spectrum of SCM-38 molecular sieve includes the X-ray diffraction peaks shown in Table 8:

[0099] Table 8

[0100]

[0101]

[0102] [Example 9]

[0103] Weigh 24g of water, 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor A and stir at room temperature for 3h. Then add 1.6g of triethylamine and then 6.1g of 25wt% tetrapropylammonium hydroxide solution. After stirring at room temperature for 3h, add 1g of 40wt% HF solution, stir evenly and place in a tetrafluoroethylene-lined autoclave. Crystallize at 120℃ for 80h; then raise the temperature to 200℃ and crystallize at this temperature for 4h. After cooling, centrifuge, wash and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=0.98:1 in molar ratio. The XRD spectrum of SCM-38 molecular sieve includes the main X-ray diffraction peaks shown in Table 9:

[0104] Table 9

[0105] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.22 100 10.79 23 11.59 9 14.35 21 21.36 11 21.78 20 27.27 7 28.68 25

[0106] [Example 10]

[0107] Weigh 24g of water, add 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor A, and stir at room temperature for 3h; then add 1.8g of 4wt% silica sol, stir evenly, add 1.6g of triethylamine, and then add 4.4g of 25wt% tetraethylammonium hydroxide aqueous solution, stir at room temperature for 4h, add 1g of 40wt% HF solution, stir evenly, and then put into a tetrafluoroethylene-lined autoclave. Crystallize at 150℃ for 66 hours; then heat to 180℃ and crystallize at this temperature for 12 hours. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is SiO2:Al2O3:P2O5=0.07:1.1:1 in molar ratio. The XRD spectrum of SCM-38 molecular sieve is shown in Figure 5 , namely including the main X-ray diffraction peaks shown in Table 10:

[0108] Table 10

[0109] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.19 100 10.82 22 11.59 10 14.33 22 21.35 16 21.86 33 27.36 11 28.73 27

[0110] [Example 11]

[0111] Weigh 24g of water, add 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor A, and stir at room temperature for 3h; then add 2.76g of N,N,N,'N'-tetramethylhexanediamine, and then add 4.4g of 25wt% tetraethylammonium hydroxide aqueous solution. After stirring at room temperature for 3h, add 1g of 40wt% HF solution, stir evenly, and then put into a tetrafluoroethylene-lined autoclave. Crystallize at 160℃ for 36h and 190℃ for 6h; after cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=1.15:1 in molar ratio. The XRD pattern of SCM-38 molecular sieve is shown in Figure 6 , namely including the main X-ray diffraction peaks shown in Table 11:

[0112] Table 11

[0113] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.21 100 10.80 20 11.60 9 14.35 23 21.34 16 21.85 28 27.34 11 28.74 27

[0114] [Example 12]

[0115] Weigh 24g of water, add 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor A, and stir at room temperature for 3h; then add 1.59g of cyclohexylamine, and then add 4.4g of 25wt% tetraethylammonium hydroxide aqueous solution, stir at room temperature for 3h, then add 1g of 40wt% HF solution, stir evenly and put into a tetrafluoroethylene-lined autoclave. Crystallize at 140℃ for 60 hours; then heat to 180℃ and crystallize at this temperature for 8 hours. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=1.1:1 in molar ratio. The XRD spectrum of SCM-38 molecular sieve is shown in Figure 7 , namely including the main X-ray diffraction peaks shown in Table 12:

[0116] Table 12

[0117] 2θ(°) <![CDATA[Relative intensity, [(I / I0)×100]]]> 7.18 100 10.82 27 11.63 9 14.34 26 21.40 27 21.79 39 27.36 13 28.73 35

[0118] [Example 13]

[0119] Weigh 24g of water, add 2.73g of aluminophosphate precursor B, and stir at room temperature for 3h; then add 1.6g of triethylamine, and then add 0.5g of 25wt% tetraethylammonium hydroxide aqueous solution, stir at room temperature for 3h, then add 1g of 40wt% HF solution, stir evenly and put into a tetrafluoroethylene-lined autoclave. Crystallize at 140℃ for 66 hours; then heat to 180℃ and crystallize at this temperature for 12 hours. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry to obtain SCM-38 molecular sieve, whose chemical composition is Al2O3:P2O5=1.2:1 in molar ratio. XRD of SCM-38 molecular sieve is shown in Figure 8 , namely including the main X-ray diffraction peaks shown in Table 13:

[0120] Table 13

[0121]

[0122]

[0123] [Comparative Example 1]

[0124] Weigh 24g of water, add 6.2g of aluminum isopropoxide, stir at room temperature for 1h, then add 3.51g of phosphoric acid, stir at room temperature for 3h; add 1.6g of triethylamine, then add 4.4g of 25wt% tetraethylammonium hydroxide aqueous solution, stir at room temperature for 3h, then add 1g of 40wt% HF solution, stir evenly, and then put into a tetrafluoroethylene-lined autoclave. Crystallize at 140℃ for 60h, then at 180℃ for 18h; cool, centrifuge, wash, and dry. The obtained product is not SCM-38 molecular sieve, and its XRD diffraction pattern is as follows Figure 9 shown.

[0125] [Comparative Example 2]

[0126] Weigh 24g of water, add 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor mixture A, and stir at room temperature for 3h. Then add 1.6g of triethylamine, stir at room temperature for 3h, then add 1g of 40wt% HF solution, stir evenly, and place in a tetrafluoroethylene-lined autoclave. Crystallize at 140°C for 60h, then at 180°C for 18h. After cooling, centrifuge, wash, and dry, the obtained product is not SCM-38 molecular sieve, and its XRD diffraction pattern is as follows: Figure 10 shown.

[0127] [Comparative Example 3]

[0128] Weigh 24g of water, add 3.1g of aluminum isopropoxide and 6g of aluminophosphate precursor mixture A, and stir at room temperature for 3h. Add 1.6g of triethylamine, then add 4.4g of 25wt% tetraethylammonium hydroxide aqueous solution, stir at room temperature for 3h, and then place in a tetrafluoroethylene-lined autoclave. Crystallize at 140℃ for 60h, then at 180℃ for 18h. After cooling, separate, wash (repeat the centrifugal washing operation 2-3 times), and dry. The obtained product is not SCM-38 molecular sieve, and its XRD diffraction pattern is as follows: Figure 11 shown.

Claims

1. An SCM-38 molecular sieve, characterized in that The chemical composition of the SCM-38 molecular sieve includes, by molar ratio: SiO2:Al2O3:P2O5=0-0.1:0.8-1.5:1, and the XRD spectrum of the SCM-38 molecular sieve includes X-ray diffraction peaks at 2θ of 7.20±0.1, 10.81±0.1, 11.60±0.1, 14.32±0.1, 21.39±0.1, 21.83±0.1, 27.31±0.1, and 28.72±0.1, among which the strongest peak is at 2θ of 7.20±0.

1.

2. The SCM-38 molecular sieve according to claim 1, characterized in that The XRD pattern of the SCM-38 molecular sieve includes the X-ray diffraction peaks shown in the following table: 。 3. The method for preparing the SCM-38 molecular sieve according to claim 1 or 2, comprising: a) mixing an aluminophosphate precursor, an organic base R1, an organic substance R2, a fluorine source, water, an optional aluminum source A, and an optional silicon source to obtain a synthesis mother solution; b) liquid crystallizing the synthetic mother liquid described in step a) to obtain SCM-38 molecular sieve; Wherein, the organic base R1 is one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide; the organic compound R2 is one or more of N,N,N,'N'-tetramethylhexanediamine, triethylamine, or cyclohexylamine; The aluminophosphate precursor has a chemical composition as shown in the formula "Al2O3:xP2O5", wherein 0.8≤x≤2; the XRD pattern of the aluminophosphate precursor mainly includes the X-ray diffraction peaks shown in the following table: 。 4. The preparation method according to claim 3, characterized in that: In step a), the XRD pattern of the aluminophosphate precursor further includes the X-ray diffraction peaks shown in the following table: 。 5. The preparation method according to claim 3, characterized in that: In step a), the XRD pattern of the aluminophosphate precursor further includes the X-ray diffraction peaks shown in the following table: 。 6. The preparation method according to claim 3, characterized in that: In the synthetic mother liquor, the molar ratio of each material is as follows: silicon source is calculated as SiO2, aluminum source A is calculated as Al2O3, phosphate aluminate precursor is calculated as Al2O3 and P2O5, organic base R1, organic matter R2, fluorine source is calculated as HF and water is calculated as H2O, (0-0.1)SiO2: (0.88-1.3)Al2O3: 1P2O5: (0.3-0.8)R1: (1-2)R2: (0.5-1.8)HF: (50-130)H2O.

7. The preparation method according to claim 3, characterized in that: The aluminum source A is selected from one or more of pseudo-boehmite, aluminum isopropoxide, aluminum sol, and aluminum oxide; the silicon source is selected from one or more of silica sol and fumed silica; and the fluorine source is selected from HF aqueous solution.

8. The preparation method according to any one of claims 3 to 7, characterized in that: In step b), the crystallization conditions are as follows: the first stage crystallization temperature is 120° C.-165° C., and the crystallization time is 24-84 hours; the second stage crystallization temperature is 170° C.-200° C., and the crystallization time is 2-24 hours.

9. The preparation method according to claim 8, characterized in that: In step b), the crystallization conditions are as follows: the first stage crystallization temperature is 120° C.-160° C., and the crystallization time is 36-80 hours; the second stage crystallization temperature is 180° C.-200° C., and the crystallization time is 4-18 hours.

10. A molecular sieve composition comprising the molecular sieve according to claim 1 or 2 or the molecular sieve prepared according to the preparation method according to any one of claims 3 to 9, and a binder.

11. Use of the molecular sieve according to claim 1 or 2, or the molecular sieve prepared according to the preparation method according to any one of claims 3 to 9, or the molecular sieve composition according to claim 10 in an adsorbent or catalyst.

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