A novel high-silica zeolite molecular sieve material NJU120-4, a preparation method and use thereof

Abstract

The application discloses a novel high-silicon zeolite molecular sieve material NJU120-4 and a preparation method and application thereof. The zeolite molecular sieve is composed of two forms of NJU120-4A and NJU120-4B, wherein the NJU120-4A form has a chiral pore structure, and the framework structures of T(Si, Al)O4 tetrahedrons in the two forms A and B both have a three-dimensional pore system with 12*10*8-membered rings. The application prepares a high-silicon zeolite molecular sieve NJU120-4 with a novel topology structure by designing a novel organic structure directing agent and through a hydrothermal reaction. The high-silicon zeolite molecular sieve has a schematic chemical composition as shown in a formula "x(M 1 / n XO2) * yYO2 * SiO2", wherein M is selected from H + an inorganic cation with a charge of +n, X is a trivalent element, Y is a tetravalent element other than silicon, 0 <= x <= 0.3, and 0 <= y <= 0.1. The application further provides a preparation method of the material and application of the material in loading, adsorption, separation or catalysis.

Description

Technical Field

[0001] This invention relates to the fields of materials science and chemical engineering, specifically to a novel high-silica zeolite molecular sieve material, its preparation method, and its applications. Background Technology

[0002] Zeolite molecular sieve materials have been widely used in petrochemical, fine chemical, energy conversion and storage, and biomedicine fields due to their unique pore structure and catalytic properties. However, zeolite molecular sieve materials synthesized by existing technologies suffer from problems such as single pore size, weak acidity, and low activity, which limit their application in certain specific fields. Therefore, developing high-silica zeolite molecular sieve materials with novel topologies and superior properties has significant scientific and practical value. Summary of the Invention

[0003] To address the above-mentioned shortcomings of existing technologies, this invention provides a novel high-silica zeolite molecular sieve material, NJU120-4, with a unique 12×10×8 membered ring three-dimensional pore system composed of two co-occurring forms, A and B, wherein form A possesses a chiral pore structure. This invention also provides a method for preparing this material and its application in loading, adsorption, separation, or catalytic processes.

[0004] To achieve the above objectives, the present invention provides the following technical solution: The X-ray diffraction characteristics of the zeolite molecular sieve NJU120-4 before calcination are as follows:

[0005] Table A1, X-ray diffraction of NJU120-4 powder before calcination;

[0006]

[0007]

[0008] In the above data, w, mw, m, s, and vs represent the diffraction peak intensities. w is weak, mw is moderately weak, m is moderate, s is strong, and vs is very strong. w is less than 10, mw is 10-20, m is 20-40, s is 40-70, and vs is greater than 70.

[0009] Preferably, the X-ray diffraction characteristics of the calcined zeolite molecular sieve NJU120-4 powder are as follows:

[0010] Table A2, X-ray diffraction characteristics of NJU120-4 powder after calcination;

[0011]

[0012] In the above data, w, mw, m, s, and vs represent the diffraction peak intensities. w is weak, mw is moderately weak, m is moderate, s is strong, and vs is very strong. w is less than 10, mw is 10-20, m is 20-40, s is 40-70, and vs is greater than 70.

[0013] Preferably, the zeolite molecular sieve is composed of two forms, NJU120-4A and NJU120-4B, wherein the NJU120-4A form has a chiral channel structure, and the framework structure composed of T(Si,Al)O4 tetrahedra in both forms A and B has a three-dimensional channel system of 12×10×8-membered rings.

[0014] Preferably, the NJU120-4A morphological framework structure is monoclinic, with space group P2(1)(No.4), and cell parameters as follows: α=90°, β=90.24±2.0°, γ=90°.

[0015] Preferably, the NJU120-4B morphological framework structure is monoclinic, with space group Pc (No. 7), and cell parameters as follows: α=90°, β=120.78±2.0°, γ=90°.

[0016] Preferably, the schematic chemical composition of the zeolite molecular sieve is "x(M 1 / n The schematic chemical composition shown is XO2)·yYO2·SiO2”, where M is selected from H + An ion or an inorganic cation with a charge of +n, where X is a trivalent element such as aluminum, gallium, boron, iron, chromium, or a combination thereof, and Y is a tetravalent element such as germanium, titanium, tin, vanadium, or a combination thereof, excluding silicon, where 0≤x≤0.3 and 0≤y≤0.1.

[0017] A method for synthesizing high-silica zeolite molecular sieve NJU120-4, the method comprising:

[0018] (1) Mixing a silicon source, an aluminum source, other trivalent and tetravalent elements that are neither silicon nor aluminum, an organic template agent, and water, and optionally a mineralizing agent (F- or OH-), yields a mixture;

[0019] (2) Crystallize the mixture;

[0020] (3) The crystallized product is calcined to remove the template agent.

[0021] 8. The method according to claim 7, characterized in that: the organic template agent has the spatial configuration represented by the following general formula:

[0022]

[0023] Wherein, R1, R2, and R3 are phenyl and cyclohexyl, respectively, and R4 is C6. 1-4 Alkyl (methyl, ethyl, propyl, butyl), cyclohexyl, X is P (phosphorus), N (nitrogen), R1, R2, R3 are preferably cyclohexyl, R4 is preferably n-butyl, and X is preferably phosphorus, i.e.

[0024] Preferably, the method includes:

[0025] (1) Under stirring, a silicon source, an aluminum source, a non-silicon, non-aluminum tetravalent and trivalent element source as described in claim 6, an organic template agent, water, and an optional mineralizer (F- or OH-) are mixed uniformly in proportion to form a reactive gel. The chemical composition of the reactive gel is rROH:a(OH- or F-):xAl2O3:zX2O3:yYO2:SiO2:wH2O, where R represents the positively charged group of the organic template agent as described in claim 8, X represents the non-aluminum trivalent element as described in claim 6, and Y represents the non-silicon tetravalent element as described in claim 6. The preferred value ranges of r, a, x, z, y, and w are: r = 0.1-2.0, a = 0-2.0, x = 0-0.3, z = 0-0.3, y = 0-0.1, w = 1-40.

[0026] (2) Place the reaction gel under an infrared lamp or in an oven to remove excess solvent, then transfer the reaction gel to a stainless steel reactor and crystallize it under sealed conditions at a temperature of 80-240°C, preferably 120-220°C, for 1-60 days, preferably 2-45 days.

[0027] (3) After washing and drying the crystallized product, calcine it in an air atmosphere at 300-850℃ for 2-6 hours.

[0028] Beneficial effects: Unique topology and pore system: The high-silica zeolite molecular sieve NJU120-4 of this invention has a novel three-dimensional pore system of 12×10×8-membered rings, composed of two forms, NJU120-4A and NJU120-4B, in which the NJU120-4A form has a chiral pore structure; this unique structure provides more channels and active sites for molecular transport and reaction, which helps to improve the efficiency and selectivity of the molecular sieve in catalysis, adsorption and other processes;

[0029] High thermal and hydrothermal stability: Due to its high silicon content and stable framework structure, NJU120-4 molecular sieve exhibits excellent stability under high temperature and hydrothermal conditions; this enables the molecular sieve to work stably for a long time in harsh industrial environments, reducing the trouble of frequent replacement or regeneration due to molecular sieve deactivation and lowering the cost of industrial applications.

[0030] Excellent catalytic performance: The novel topology and pore system enable NJU120-4 molecular sieve to have higher activity and selectivity in catalytic reactions; its chiral pore structure may have unique catalytic effects on certain chiral reactions, and can generate the desired products with high selectivity, improve the atom economy of the reaction and the purity of the products, which is of great significance for the synthesis of chiral compounds in fine chemical, pharmaceutical and other fields.

[0031] Broad industrial application prospects: Given its unique structure and excellent performance, NJU120-4 molecular sieve can be widely used in many fields such as petrochemicals, fine chemicals, energy conversion and storage, and biomedicine. For example, it has potential application value in petroleum catalytic cracking, hydrocarbon conversion, gas separation, and pollutant removal, and is expected to provide new material support for the optimization and upgrading of related industrial processes.

[0032] Innovation of the synthesis method: This invention also provides a novel synthesis method that successfully prepares high-silica zeolite molecular sieves with novel topologies by designing specific organic structure directing agents and optimizing synthesis conditions. This synthesis method has the advantages of simple operation, mild conditions, and easy control, which is conducive to realizing large-scale industrial production and provides an effective technical means for the development and application of novel molecular sieve materials.

[0033] Enriching the family of zeolite molecular sieve structures: The discovery of NJU120-4 molecular sieve adds a new member to the family of zeolite molecular sieve materials, further expanding the structural types and performance range of zeolite molecular sieves. This not only helps to deepen the understanding of the relationship between the structure and properties of zeolite molecular sieves, but also provides important theoretical reference and experimental basis for the future design and synthesis of novel molecular sieve materials with specific properties. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0035] Figure 1 The X-ray powder diffraction pattern (Cu target Kα rays) of the NJU120-4 zeolite molecular sieve of the present invention before and after the template agent was removed by high-temperature calcination at 600℃.

[0036] Figure 2 This is a schematic diagram of the pores in the crystal structures of NJU120-4 zeolite molecular sieves A and B of the present invention along different directions.

[0037] Figure 3 This is a transmission electron microscope (TEM) image of the NJU120-4 zeolite molecular sieve of the present invention.

[0038] Figure 4 This is a scanning electron microscope (SEM) image of the NJU120-4 zeolite molecular sieve of the present invention. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-4 The specific embodiments of the present invention will be described in further detail below.

[0040] Depend on Figure 1-4 This invention provides a novel high-silica zeolite molecular sieve material, its preparation method, and its applications, including the structural characteristics of the high-silica zeolite molecular sieve NJU120-4.

[0041] Chemical composition: having the following formula "x(M 1 / n The schematic chemical composition shown is XO2)·yYO2·SiO2”, where M is selected from H + An ion or an inorganic cation with a charge of +n, where X is a trivalent element and Y is a tetravalent element other than silicon, 0≤x≤0.3 and 0≤y≤0.1.

[0042] Powder X-ray diffraction characteristics:

[0043] Before roasting:

[0044]

[0045]

[0046] After roasting:

[0047]

[0048] Skeletal structure features: It is composed of two shapes, NJU120-4A and NJU120-4B, with NJU120-4A having a chiral channel structure. The skeleton structure composed of T(Si,Al)O4 tetrahedra in both shapes A and B has a three-dimensional channel system of 12×10×8 elemental rings.

[0049] The framework structure of NJU120-4A is monoclinic, with a chiral space group of P2(1)(No.4), and the cell parameters are: With α = 90°, β = 90.24 ± 2.0°, and γ = 90°, the framework of this zeolite molecular sieve composed of T (Si, Al) atoms has the topological characteristics shown in the table below.

[0050] Table A3

[0051]

[0052] The NJU120-4B crystal structure is monoclinic, with space group Pc (No. 7) and cell parameters as follows: With α = 90°, β = 120.78 ± 2.0°, and γ = 90°, the framework of this zeolite molecular sieve composed of T (Si, Al) atoms has the topological characteristics shown in the table below.

[0053] Table A4.

[0054]

[0055] The organic template agent in this invention has the spatial configuration represented by the following general formula:

[0056]

[0057] Wherein, R1, R2, and R3 are phenyl and cyclohexyl, respectively, and R4 is C6. 1-4 Alkyl (methyl, ethyl, propyl, butyl), cyclohexyl, X is P (phosphorus), N (nitrogen), R1, R2, R3 are preferably cyclohexyl, R4 is preferably n-butyl, and X is preferably phosphorus, i.e.

[0058] Applications of high-silica zeolite molecular sieve NJU120-4

[0059] The high-silica zeolite molecular sieve NJU120-4 of the present invention, due to its novel topology, unique pore system, and high thermal and hydrothermal stability, can be further applied to loading, adsorption, separation or catalytic processes, and may exhibit unique properties.

[0060] Example 1: Synthesis of template agent

[0061] Taking tricyclohexylbutylphosphine as an example, the general synthesis process of template agents is illustrated. 28.04 g of tricyclohexylphosphine and 200 ml of acetonitrile were mixed in a 500 ml round-bottom flask. At room temperature, 36.5 g of n-butane iodide was added dropwise to the mixture. The system was heated to 80 °C with stirring and reacted for one day. The solvent was removed by rotary evaporation of the reaction mixture to obtain a crude product. Recrystallization from methanol yielded 44.55 g of the product, with a yield of 95%. The product was characterized by liquid NMR and electrospray mass spectrometry, confirming it as the target compound. The obtained product was dispersed in 400 ml of deionized water and subjected to column exchange using a pre-treated IRN-78 strong-base anion exchange resin (manufacturer: ThermoFisher). The resulting aqueous solution of template agent 6 was obtained. An appropriate amount of this solution was weighed and standardized with 0.1 mol / L hydrochloric acid solution, using phenolphthalein as an indicator. The standardized structure confirmed that the exchange efficiency of iodide to hydroxide reached 97%.

[0062] Example 2: Synthesis of Zeolite Molecular Sieves

[0063] The gel synthesized from zeolite molecular sieves was prepared according to a molar ratio of 0.5 ROH:0.025 Al₂O₃:SiO₂:15 H₂O. The general steps are as follows: Weigh an appropriate amount of the template agent solution from Example 1 after exchange, add 0.02 mmol (0.005 g) of aluminum isopropoxide powder, and stir for about half an hour. Then add 1.0 mmol (0.212 g) of tetraethyl orthosilicate and stir at room temperature for about two hours until the tetraethyl orthosilicate is completely dissolved. After stirring until homogeneous, place the mixed gel under an infrared lamp or in an oven at 80°C to remove excess solvent. Transfer the final reaction gel to a 5 ml stainless steel reactor with a polytetrafluoroethylene liner and react at 190°C for 21 days under sealed conditions. The product is washed twice with water and twice with ethanol, and then dried for later use. The product was directly identified by X-ray powder diffraction and confirmed to be NJU120-4. Take an appropriate amount of sample and calcine it in an air atmosphere at 600℃ in a muffle furnace for 6 hours to remove the template agent. The product is washed with water, centrifuged and dried to obtain NJU120-4 zeolite molecular sieve product.

[0064] According to one aspect of the present invention, the chemical composition of the reactive gel is rROH:a(OH- or F-):xAl2O3:zX2O3:yYO2:SiO2:wH2O, wherein R represents the positively charged group of the organic template agent according to claim 8, X represents the non-aluminum trivalent element according to claim 6, and Y represents the non-silicon tetravalent element according to claim 6; the preferred value ranges of r, a, x, z, y and w are respectively: r = 0.1-2.0, a = 0-2.0, x = 0-0.3, z = 0-0.3, y = 0-0.1, w = 1-40;

[0065] In the illustrative chemical composition rROH:a(OH- or F-):xAl2O3:zX2O3:yYO2:SiO2:wH2O, where R represents the positively charged group of the organic template agent, which is selected from any one or more of the following:

[0066]

[0067]

[0068] Preferred

[0069] Beneficial Effects: Unique Topology and Pore System: The high-silica zeolite molecular sieve NJU120-4 of this invention possesses a novel three-dimensional pore system of 12×10×8-membered rings, composed of two co-existing forms, NJU120-4A and NJU120-4B, with NJU120-4A exhibiting a chiral pore structure. This unique structure provides more channels and active sites for molecular transport and reactions, contributing to improved efficiency and selectivity of the molecular sieve in catalysis, adsorption, and other processes.

[0070] High thermal and hydrothermal stability: Due to its high silicon content and stable framework structure, NJU120-4 molecular sieve exhibits excellent stability under high temperature and hydrothermal conditions. This enables the molecular sieve to operate stably for a long time in harsh industrial environments, reducing the hassle of frequent replacement or regeneration due to molecular sieve deactivation and lowering the cost of industrial applications.

[0071] Excellent catalytic performance: The novel topology and pore system of NJU120-4 molecular sieves enable them to exhibit higher activity and selectivity in catalytic reactions. Its chiral pore structure may possess unique catalytic effects for certain chiral reactions, enabling highly selective generation of desired products, improving atom economy and product purity, and holding significant importance for the synthesis of chiral compounds in fine chemicals, pharmaceuticals, and other fields.

[0072] Broad Industrial Application Prospects: Given its unique structure and excellent performance, NJU120-4 molecular sieves can be widely used in various fields such as petrochemicals, fine chemicals, energy conversion and storage, and biomedicine. For example, it has potential application value in petroleum catalytic cracking, hydrocarbon conversion, gas separation, and pollutant removal, and is expected to provide new material support for the optimization and upgrading of related industrial processes.

[0073] Innovation of the Synthesis Method: This invention also provides a novel synthesis method that successfully prepares high-silica zeolite molecular sieves with novel topologies by designing specific organic structure-directing agents and optimizing synthesis conditions. This synthesis method has advantages such as simple operation, mild conditions, and ease of control, which facilitates large-scale industrial production and provides an effective technical means for the development and application of novel molecular sieve materials.

[0074] Enriching the Zeolite Molecular Sieves Family: The discovery of NJU120-4 molecular sieve adds a new member to the zeolite molecular sieve material family, further expanding the structural types and performance range of zeolite molecular sieves. This not only contributes to a deeper understanding of the relationship between the structure and properties of zeolite molecular sieves, but also provides important theoretical references and experimental basis for the future design and synthesis of novel molecular sieve materials with specific properties.

[0075] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-silica zeolite molecular sieve NJU120-4, characterized in that, The X-ray diffraction characteristics of the zeolite molecular sieve NJU120-4 powder before calcination are as follows: Table A1, X-ray diffraction of NJU120-4 powder before calcination; In the above data, w, mw, m, s, and vs represent the diffraction peak intensities. w is weak, mw is moderately weak, m is moderate, s is strong, and vs is very strong. w is less than 10, mw is 10-20, m is 20-40, s is 40-70, and vs is greater than 70.

2. The high-silica zeolite molecular sieve NJU120-4 according to claim 1, characterized in that: The X-ray diffraction characteristics of the calcined zeolite molecular sieve NJU120-4 powder are as follows: Table A2, X-ray diffraction characteristics of NJU120-4 powder after calcination; In the above data, w, mw, m, s, and vs represent the diffraction peak intensities. w is weak, mw is moderately weak, m is moderate, s is strong, and vs is very strong. w is less than 10, mw is 10-20, m is 20-40, s is 40-70, and vs is greater than 70.

3. The high-silica zeolite molecular sieve NJU120-4 according to claims 1-2, characterized in that: The zeolite molecular sieve is composed of two forms, NJU120-4A and NJU120-4B, in which the NJU120-4A form has a chiral channel structure, and the framework structure composed of T(Si,Al)O4 tetrahedra in both forms A and B has a three-dimensional channel system of 12×10×8-membered rings.

4. The high-silica zeolite molecular sieve NJU120-4 according to claim 3, characterized in that: The framework structure of the NJU120-4A molecular sieve is monoclinic, with space group P2(1)(No.4), and the cell parameters are: α=90°, β=90.24±2.0°, γ=90°, and the framework composed of T(Si, Al) atoms of the NJU120-4A molecular sieve has the topological characteristics shown in Table A3 below. Table A3 5. The high-silica zeolite molecular sieve NJU120-4 according to claim 3, characterized in that: The framework structure of the NJU120-4B molecular sieve is monoclinic, with space group Pc(No.7), and the cell parameters are as follows: α=90°, β=120.78±2.0°, γ=90°, the framework composed of T(Si, Al) atoms of the NJU120-4B molecular sieve has the topological characteristics shown in Table A4 below. Table A4 6. The high-silica zeolite molecular sieve NJU120-4 according to claims 1-5, characterized in that: The schematic chemical composition of the zeolite molecular sieve is "x(M 1 / n The schematic chemical composition shown is XO2)·yYO2·SiO2”, where M is selected from H + An ion or an inorganic cation with a charge of +n, where X is a trivalent element such as aluminum, gallium, boron, iron, chromium, or a combination thereof, and Y is a tetravalent element such as germanium, titanium, tin, vanadium, or a combination thereof, excluding silicon, where 0≤x≤0.3 and 0≤y≤0.

1.

7. The method for synthesizing the high-silica zeolite molecular sieve NJU120-4 according to any one of claims 1-6, characterized in that, The synthesis method includes: (1) A mixture is prepared by mixing a silicon source, an aluminum source, a tetravalent and trivalent element that is neither silicon nor aluminum as described in claim 6, an organic template agent, water, and an optional mineralizer (F- or OH-). (2) Crystallize the mixture; (3) The crystallized product is calcined to remove the template agent.

8. The method according to claim 7, characterized in that: The organic template agent has the spatial configuration represented by the following general formula: Wherein, R1, R2, and R3 are phenyl and cyclohexyl, respectively, and R4 is C6. 1-4 Alkyl (methyl, ethyl, propyl, butyl), cyclohexyl, X is P (phosphorus), N (nitrogen), R1, R2, R3 are preferably cyclohexyl, R4 is preferably n-butyl, and X is preferably phosphorus, i.e.

9. The method according to claims 7-8, characterized in that: The method includes: (1) Under stirring, silicon source, aluminum source, non-silicon and non-aluminum tetravalent and trivalent elements as described in claim 6, organic template agent, water, and optional mineralizer (F- or OH-) are mixed evenly in proportion to form a reactive gel. The chemical composition of the reactive gel is rROH:a(OH- or F-):xAl2O3:zX2O3:yYO2:SiO2:wH2O, where R represents the positively charged group of the organic template agent as described in claim 8, X represents the non-aluminum trivalent element as described in claim 6, and Y represents the non-silicon tetravalent element as described in claim 6. The preferred value ranges of r, a, x, z, y, and w are: r = 0.1-2.0, a = 0-2.0, x = 0-0.3, z = 0-0.3, y = 0-0.1, w = 1-40. (2) Place the reaction gel under an infrared lamp or in an oven to remove excess solvent, then transfer the reaction gel to a stainless steel reactor and crystallize it under sealed conditions at a temperature of 80-240°C, preferably 120-220°C, for 1-60 days, preferably 2-45 days. (3) After washing and drying the crystallized product, calcine it in an air atmosphere at 300-850℃ for 2-6 hours.

10. A molecular sieve composition, characterized in that: The composition contains the silicate zeolite molecular sieves as described in claims 1-6.

11. An application of the novel silicate zeolite molecular sieve according to claims 1-6, characterized in that: The use of the silicate zeolite molecular sieves of claims 1-6 or the molecular sieve composition of claim 10 as energy storage materials, chemical sensing materials, carriers, adsorbents, separating agents or catalysts.

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