Synthesis method for constructing molecular sieve by using Zr4L6 tetrahedral cage

Abstract

The invention provides a Zr4L6-SOD molecular sieve crystalline matter, which is a three-dimensional molecular sieve framework material formed by coordination connection of a Zr4L6 cage and a trinuclear Ba3 cluster unit Ba3 (OH) 6 (H2O) 2 (MeCN) 2, has an SOD topological network structure, and has an X-ray powder diffraction pattern basically as shown in Figure 2; wherein L in the Zr4L6 cage is pamoic acid; the trinuclear Ba3 cluster unit Ba3 (OH) 6 (H2O) 2 (MeCN) 2 is a Ba3 cluster formed by bridging three Ba through-OH and simultaneously coordinating two water molecules and two acetonitrile molecules. The Zr4L6-SOD molecular sieve prepared by the method has an SOD topological network structure, has a relatively large aperture, and is expected to be used in the fields of adsorption, separation and photoelectrocatalysis.

Description

Technical Field

[0001] This invention belongs to the field of crystal material preparation technology, specifically relating to a method for synthesizing molecular sieves using Zr4L6 tetrahedral cages. Background Technology

[0002] Zeolite molecular sieves have become a hot research topic due to their attractive structure, regular pore distribution, high stability, and unique application properties in adsorption, separation, and catalysis. The most typical type is the zeolite molecular sieve formed by interconnecting silicon-oxygen tetrahedra or aluminum-oxygen tetrahedra through oxygen bridges (each oxygen atom is shared by two adjacent tetrahedra). However, the small pore size of this traditional molecular sieve material makes it difficult for large molecules to enter the pores, which greatly limits its industrial applications. Zr4L6 (L = pamoic acid) tetrahedral cages possess high solubility, high stability, and abundant oxygen coordination sites. Through multi-level assembly, various types of cage-based crystalline materials can be constructed. Crucially, it possesses a highly symmetric tetrahedral environment and calixarene-like coordination vertices, which can serve as 4-connected building blocks, coordinating with single metal or metal cluster units to form zeolite-type framework materials. This assembly strategy allows for the construction of molecular sieve materials with larger pore sizes, providing a new synthetic strategy for novel zeolite molecular sieve materials. Summary of the Invention

[0003] To achieve the above objectives, this invention provides a novel zeolite molecular sieve material, its preparation method, and its applications. This invention utilizes Zr4L6 cages as building blocks to synthesize a crystalline molecular sieve, Zr4L6-SOD. The Zr4L6-SOD molecular sieve possesses an SOD topological network structure and a large pore size, making it promising for applications in adsorption, separation, and photoelectrocatalysis.

[0004] The technical solution of the present invention is as follows:

[0005] A Zr4L6-SOD molecular sieve crystalline material is a three-dimensional molecular sieve framework material formed by the coordination connection of Zr4L6 cages and trinuclear Ba3 cluster units Ba3(OH)6(H2O)2(MeCN)2. It possesses an SOD topological network structure and exhibits essentially the same properties as... Figure 2 The X-ray powder diffraction pattern shown;

[0006] In Zr4L6 cage, L represents pamoic acid; the trinuclear Ba3 cluster unit Ba3(OH)6(H2O)2(MeCN)2 is a Ba3 cluster formed by three Ba ​​molecules connected by -OH bridging and simultaneously coordinating two water molecules and two acetonitrile molecules.

[0007] According to an embodiment of the present invention, free acetonitrile molecules exist in the pores of the Zr4L6-SOD molecular sieve crystalline three-dimensional molecular sieve framework material.

[0008] According to an embodiment of the present invention, the structural unit of the Zr4L6-SOD molecular sieve crystal includes a Zr4L6 cage, a trinuclear Ba3 cluster unit Ba3(OH)6(H2O)2(MeCN)2 and four acetonitrile molecules.

[0009] According to an embodiment of the present invention, the crystal structure of the Zr4L6-SOD molecular sieve crystalline material is as follows: Figure 1 As shown.

[0010] According to the present invention, the Zr4L6-SOD molecular sieve crystalline material is a yellow crystalline material.

[0011] According to an embodiment of the present invention, the Zr4L6-SOD molecular sieve crystals have a relatively large size and possess the following properties: Figure 3 The crystal morphology shown.

[0012] According to an embodiment of the present invention, the Zr4L6-SOD molecular sieve crystalline material has the following crystal parameters as determined by single-crystal X-ray analysis:

[0013]

[0014] This invention also provides a method for preparing the above-mentioned Zr4L6-SOD molecular sieve crystalline material, which is a solvothermal synthesis method, including the following steps:

[0015] Zr4L6 cages and barium salts were heated and reacted in a solvent, and the solid phase was separated by cooling, which was Zr4L6-SOD molecular sieve crystalline material.

[0016] According to the present invention, the Zr4L6 cage is a molecular cage, and its preparation process can be carried out with reference to the method described in patent document CN 109678702 A.

[0017] According to an embodiment of the present invention, the barium salt is one, two or more of barium chloride, barium acetate, barium nitrate, barium sulfate, barium carbonate, barium titanate, barium chlorate, and barium peroxide, preferably barium chloride.

[0018] According to the present invention, the molar ratio of the Zr4L6 cage to the barium salt can be (0.1:1) to (5:1), for example (0.2:1) to (1.5:1) or (0.2:1) to (0.5:1).

[0019] According to the present invention, the solvent may be a mixture of urea solvents, nitrile solvents, and water. Preferably, the solvent is selected from a mixture of acetonitrile, distilled water, and tetramethylurea. The volume ratio of the three is (0.5-1):(3-6):3, for example, 0.5:3:3.

[0020] According to the present invention, the heating temperature can be 0 to 140°C; preferably 0 to 80°C, such as 0 to 30°C.

[0021] According to the present invention, the reaction time can be 3 to 240 hours; preferably 6 to 150 hours, such as 72 hours. For example, the reaction can be carried out at 0 to 30°C for 72 hours.

[0022] According to the present invention, the reaction can be carried out in a glass bottle or a polytetrafluoroethylene pressure vessel; preferably in a glass bottle.

[0023] Preferably, the reaction further includes a step of purifying the product after the reaction, the purification including: washing and separating the product obtained after the reaction. The product is further washed with a clarified mother liquor or acetonitrile solvent; preferably, it is air-dried at room temperature to obtain Zr4L6-SOD molecular sieve crystals.

[0024] Preferably, the product obtained from the washing process is prepared using acetonitrile.

[0025] The present invention also provides the use of the Zr4L6-SOD molecular sieve crystals as described above as adsorption, separation and photoelectrocatalytic materials.

[0026] Beneficial effects

[0027] The inventors have discovered that the method of this invention can construct a novel molecular sieve framework material, Zr4L6-SOD molecular sieve crystalline form. Furthermore, this synthesis process is simple, has low requirements for raw material purity, and the raw materials are readily available and inexpensive, facilitating large-scale production. Moreover, this synthesis process generates minimal pollution, meeting green environmental protection requirements. In addition, the Zr4L6-SOD molecular sieve prepared using this synthesis method possesses an SOD topological network structure. The Zr4L6-SOD molecular sieve has a large pore size and holds promise for applications in adsorption, separation, and photoelectrocatalysis. Attached Figure Description

[0028] Figure 1 The crystal structure diagram is shown for the Zr4L6-SOD molecular sieve crystalline material prepared in Example 1.

[0029] Figure 2 The image shows the X-ray powder diffraction pattern of the Zr4L6-SOD molecular sieve crystalline material prepared in Example 1.

[0030] Figure 3This is a single-crystal photograph of the Zr4L6-SOD molecular sieve crystalline material prepared in Example 1. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the scope of protection of the invention.

[0032] Unless otherwise stated, all reagents used in this invention are commercially available.

[0033] The single-crystal structure analysis of this invention was performed using Rigaku's Supernova single-crystal diffractometer from Japan.

[0034] The X-ray source used in X-ray powder diffraction testing is Ga-Kα rays.

[0035] Example 1

[0036] Weigh out 80 mg (0.02 mmol) of yellow Zr4L6 crystalline material, 20 mg (0.1 mmol) of barium chloride, 0.5 mL of tetramethylurea, 3 mL of distilled water and 3 mL of acetonitrile and place them in a 20 mL glass bottle. Mix them thoroughly at room temperature and then keep the mixture at room temperature for 3 days. Remove the bottle and let it stand for 2 days. Separate the solid phase and wash the solid phase with clean mother liquor to obtain yellow polyhedral Zr4L6-SOD molecular sieve crystals.

[0037] The crystal parameters of the Zr4L6-SOD molecular sieve crystalline material prepared in Example 1 are shown in Table 1.

[0038] Table 1

[0039]

[0040]

[0041] The product prepared in Example 1 was characterized, and the structural confirmation data are shown in [the table below]. Figure 1-3 .

[0042] Depend on Figure 1 As can be seen from the crystal structure diagram, Zr4L6-SOD molecular sieve has a large pore size (nm level). Therefore, it can be used to adsorb / separate gas molecules and small organic molecules, and can also be loaded with catalytically active functional groups for use in the field of photoelectrocatalysis.

[0043] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. 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 Zr4L6-SOD molecular sieve crystalline material, characterized in that, It is a three-dimensional molecular sieve framework material formed by the coordination connection of Zr4L6 cages and trinuclear Ba3 cluster units Ba3(OH)6(H2O)2(MeCN)2, with an SOD topological network structure and an X-ray powder diffraction pattern that is basically as shown in Figure 2. In Zr4L6 cage, L represents pamoic acid; the trinuclear Ba3 cluster unit Ba3(OH)6(H2O)2(MeCN)2 is a Ba3 cluster formed by three Ba ​​molecules connected by -OH bridging and simultaneously coordinating two water molecules and two acetonitrile molecules.

2. The Zr4L6-SOD molecular sieve crystalline material according to claim 1, characterized in that, Single-crystal X-ray diffraction revealed the following crystal parameters in the Zr4L6-SOD molecular sieve crystalline form:

3. The method for preparing the Zr4L6-SOD molecular sieve crystalline material according to claim 1 or 2, characterized in that, The solvothermal synthesis method includes the following steps: Zr4L6 cages and barium salts were heated and reacted in a solvent, and the solid phase was separated by cooling, which was Zr4L6-SOD molecular sieve crystalline material.

4. The preparation method according to claim 3, characterized in that, The barium salt is one, two or more of the following: barium chloride, barium acetate, barium nitrate, barium sulfate, barium carbonate, barium titanate, barium chlorate, and barium peroxide.

5. The preparation method according to claim 3 or 4, characterized in that, The molar ratio of the Zr4L6 cage to the barium salt is (0.1:1) to (5:1).

6. The preparation method according to claim 3 or 4, characterized in that, The molar ratio of the Zr4L6 cage to the barium salt is (0.2:1) to (1.5:1).

7. The preparation method according to claim 3 or 4, characterized in that, The solvent is a mixture of urea solvents, nitrile solvents and water.

8. The preparation method according to claim 7, characterized in that, The solvent is selected from a mixture of acetonitrile, distilled water, and tetramethylurea.

9. The preparation method according to claim 3 or 4, characterized in that, The heating temperature is 0–140°C.

10. Use of the Zr4L6-SOD molecular sieve crystal as described in claim 1 or 2 as an adsorption, separation, and photoelectrocatalytic material.

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