Manganese-based metal organic framework material and preparation method thereof

Abstract

The invention belongs to the technical field of metal organic framework materials, and particularly relates to a manganese-based metal organic framework material and a preparation method thereof. The preparation method comprises the following steps: S1, dissolving manganese-based hydrated salt in an organic solvent to obtain a mixed solution A, and mixing an organic ligand with the organic solvent to obtain a mixed solution B; and S2, mixing and stirring the mixed solution B and the mixed solution A, adding an additive, carrying out a high-temperature heating reaction, and after the reaction, carrying out separation, washing and drying to obtain the manganese-based metal organic framework material. The manganese-based metal organic framework material obtained by the invention has controllable morphology and size, and can solve the problems of low regulation and control precision and complex synthesis process of a solvothermal reaction technology in the prior art. And a wider prospect is provided for the application of the Mn-MOFs material in the fields of energy, environment, catalysis, medicine and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of metal organic framework materials, and in particular relates to a manganese-based metal organic framework material and a preparation method thereof. Background Art

[0002] The existing technologies mainly include preparing Mn-MOFs by solvothermal synthesis, hydrothermal synthesis or coprecipitation, and regulating their morphology and size by changing the synthesis conditions (such as temperature, time, solvent type, precursor concentration, etc.). These methods can control the morphology and size of Mn-MOFs to a certain extent, but often have problems such as low control accuracy, poor repeatability or complex synthesis process.

[0003] The prior art closest to the present application may include the preparation of Mn-MOFs by solvothermal synthesis using specific organic ligands and manganese salts. These technical measures and product compositions can produce Mn-MOFs with a certain pore structure and specific surface area, which are suitable for applications such as catalysis, gas storage and separation. However, the prior art has limitations in precisely controlling the morphology and size of Mn-MOFs, which may lead to inconsistencies in material properties and unpredictable application effects. For example, the prior art may find it difficult to achieve precise control of the uniformity, size distribution and morphology of Mn-MOFs nanoparticles, which is crucial for the practical application of the material.

[0004] In response to the problems existing in the prior art, the technical solution of the present application aims to provide an improved method for preparing manganese-based metal organic framework materials, as well as a new morphology and size control strategy. By introducing new synthesis strategies, such as capping agents and pH adjustment, the present application can more accurately control the morphology and size of Mn-MOFs, thereby optimizing its performance in specific applications. In addition, the present application may also involve the optimization of synthesis conditions to improve the synthesis efficiency and repeatability of materials, and solve the problems of low control accuracy and complex synthesis process in the prior art. These improvements will provide broader prospects for the application of Mn-MOFs materials in the fields of energy, environment, catalysis and medicine. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a manganese-based metal organic framework material and a preparation method, comprising the following steps:

[0006] S1: dissolving a manganese-based hydrated salt in an organic solvent to obtain a mixed solution A, and mixing an organic ligand and an organic solvent to obtain a mixed solution B;

[0007] S2: Mixing the mixed solution B and the mixed solution A, stirring, adding additives, heating at high temperature, and separating, washing, and drying after the reaction to obtain a manganese-based metal organic framework material.

[0008] Furthermore, the manganese-based hydrated salt described in S1 is any one of manganese acetate tetrahydrate and manganese nitrate tetrahydrate, the mass ratio of the manganese-based hydrated salt to the organic solvent is 1:10, and the mass ratio of the organic ligand to the organic solvent is 1:10.

[0009] Furthermore, the organic solvent described in S1 is anhydrous ethanol, deionized water, N,N - Any one or more of dimethylformamide and methanol.

[0010] Furthermore, the organic ligands described in S1 are 1, 2, 4 - Tricarboxylic acid, 1,3,5 - Tricarboxylic acid, 1,2,3 - Any one or more of trimellitic acids.

[0011] Furthermore, the stirring time described in S2 is 20 min to 30 min, and the stirring speed is 200 r / min to 500 r / min.

[0012] Furthermore, the additive described in S2 is any one or more of acetic acid, sodium acetate, formic acid, sodium formate, and triethylamine.

[0013] Furthermore, the high temperature reaction temperature in S2 is 140° C. to 180° C., the reaction time is 12 h to 24 h, and the high temperature reaction process is carried out in a tetrafluoroethylene-lined high-pressure reactor.

[0014] Furthermore, the separation method is centrifugation, decantation, filtration, preferably any one of decantation, the drying temperature is 50° C. to 60° C., and the vacuum drying is maintained for 12 h to 24 h.

[0015] A manganese-based metal organic framework material has a sea urchin-like structure.

[0016] Furthermore, the particle size range of the manganese-based metal organic framework material is 0.05 μm to 30 μm.

[0017] Beneficial Effects

[0018] The present invention provides a method for preparing a manganese-based metal organic framework material, which adopts a complex coordination reaction between an organic ligand and a manganese-based hydrated salt, and directly adds an acid-base additive to perform a solvent thermal reaction to generate a manganese-based metal organic framework material. On the one hand, the basic structure of a general metal organic framework material is retained, and on the other hand, the skeleton structure extension and crystal growth rate are adjusted by various reaction parameters so that manganese-based metal organic framework materials with different particle sizes and customizable skeleton structures can be accurately obtained.

[0019] On this basis, the present invention, on the one hand, uses additives to compete with multidentate linkers for metal coordination sites, thereby adjusting the rate of framework extension and crystal growth. On the other hand, the additives can also affect the deprotonation process of the reaction by affecting the acid-base environment of the reaction system to determine the morphology of the final product, and at the same time, cooperate with other synthesis conditions (such as pH, temperature, time, solvent type, precursor concentration, material composition, etc.) to adjust the morphology size and growth rate of MOFs to obtain manganese-based metal organic framework materials of different morphology sizes. A small amount of additives usually does not affect the morphology of the crystal, but may lead to the formation of smaller non-agglomerated, fully formed particles. In the reaction, the manganese mixed solution obtained by the introduction of acidic additives has little effect on its size at a lower pH (slow deprotonation process), but its end-capping ability affects the morphology of the crystal. Therefore, sometimes additives without end-capping ability are introduced to adjust the reaction pH in order to obtain a certain different morphology. The more alkaline additives there are in the reaction, the higher the pH, so the more deprotonated organic ligand linker molecules can coordinate with metal ions, which can cause drastic changes in the crystal shape. However, when the pH of the system is too high (too many additives), the additives and organic ligand linkers compete with each other for coordination with metal ions, accompanied by an extremely fast nucleation rate, which will hinder the assembly of small nuclei or clusters, thereby forming an ordered crystal structure.

[0020] In general, the addition of additives makes it possible to obtain smaller particles because it is conducive to the supersaturation of the system and increases the nucleation rate. However, appropriate acid-base balance is also necessary to regulate the nucleation rate and prepare Mn-MOFs crystals of the desired shape.

[0021] The manganese-based metal organic framework material obtained by the present invention has a controllable morphological size, and its particle size range is 0.05μm to 30μm; the preparation method of manganese-based metal organic framework materials of various morphological sizes prepared by the method provided by the invention is simple, controllable, and the reaction process is safe and environmentally friendly. It can accurately obtain manganese-based metal organic framework materials within a customizable morphology and size range, and provides a solution to the problems of low control accuracy and complex synthesis process of solvent thermal reaction technology in the prior art. These improvements will provide broader prospects for the application of Mn-MOFs materials in the fields of energy, environment, catalysis and medicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0023] In the figure:

[0024] Figure 1 This is a scanning electron microscope image of the manganese-based metal organic framework material of Example 1 of the present invention;

[0025] Figure 2 This is a scanning electron microscope image of the manganese-based metal organic framework material of Example 5 of the present invention;

[0026] Figure 3 This is a scanning electron microscope image of the manganese-based metal organic framework material of Example 7 of the present invention;

[0027] Figure 4 This is a scanning electron microscope photograph of the manganese-based metal organic framework material of Example 11 of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with Examples 1 to 12 of the present invention and Comparative Example 1 to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The present invention affects the morphology and size of the manganese-based metal organic framework material by controlling different reaction temperatures, the types of reaction solvents, and adding additives having the same chemical functions as the organic ligands to the prepared standard solution. On the one hand, the rate of framework extension and crystal growth is adjusted by using additives to compete with multi-dentate linkers for metal coordination sites. On the other hand, the additives can also determine the morphology of the final product by affecting the acid-base environment of the reaction system.

[0030] In the examples and comparative examples, a cold field emission scanning electron microscope (SEM) of Hitachi, Japan, was used to observe the morphology of the manganese-based metal organic framework material and analyze its particle size.

[0031] Example 1

[0032] S1: Take 0.2233g of manganese nitrate tetrahydrate and dissolve it in 20ml of anhydrous ethanol with a glass rod to obtain liquid A. Take 0.1053g of 1,3,5 - Use a glass plate to stir and dissolve benzenetricarboxylic acid in 20 ml of anhydrous ethanol to obtain solution B;

[0033] S2: Pour liquid B into liquid A, stir at 100 r / min in a magnetic stirrer for 20 min, react at 170°C in a tetrafluoroethylene-lined high-pressure reactor (50 ml) for 12 h, and wash the resulting solution three times with anhydrous ethanol by decantation, and then vacuum dry at 60°C for 12 h to obtain a manganese-based metal organic framework material.

[0034] The scanning electron microscope photo of the manganese-based metal organic framework material obtained in Example 1 is shown in Figure 1 Its morphology is smooth and spherical, and its particle size ranges from 0.3μm to 0.5μm.

[0035] Example 2

[0036] S1: Weigh 0.2232g of manganese nitrate tetrahydrate and dissolve it in 20ml of anhydrous ethanol and deionized water in a ratio of 1:1 using a glass rod to obtain liquid A. Take 0.1053g of 1,3,5 - Use a glass plate to stir and dissolve benzenetricarboxylic acid in anhydrous ethanol: deionized water in a ratio of 1:1, a total of 20 ml of liquid to obtain liquid B;

[0037] S2: Pour liquid B into liquid A and stir at 100 r / min in a magnetic stirrer for 20 min. Then add 0.2 mmol of sodium acetate to the prepared standard solution and dissolve it. Then react it at 160°C in a tetrafluoroethylene-lined high-pressure reactor (50 ml) for 12 h. The obtained solution is washed three times with anhydrous ethanol by decantation and then dried in vacuum at 60°C for 12 h to obtain a manganese-based metal organic framework material.

[0038] The morphology of the manganese-based metal organic framework material obtained in Example 2 is sphere and Figure 1 Similar but with small particles on the surface, the particle size ranges from 0.3μm to 0.5μm.

[0039] Example 3

[0040] S1: Take 0.2230g of manganese nitrate tetrahydrate and dissolve it in 20ml of anhydrous ethanol with a glass rod to obtain liquid A. Take 0.1053g of 1,3,5 - The benzenetricarboxylic acid was dissolved in 20 ml of anhydrous ethanol by stirring with a glass plate to obtain solution B;

[0041] S2: Pour liquid B into liquid A and stir at 100 r / min in a magnetic stirrer for 20 min. Then, add 0.5 mmol acetic acid and 0.5 mmol triethylamine to the prepared standard solution, react at 160°C in a tetrafluoroethylene-lined high-pressure reactor (50 ml) for 12 h. The resulting solution is washed three times with anhydrous ethanol by decantation and then dried in vacuum at 60°C for 12 h to obtain a manganese-based metal organic framework material.

[0042] The manganese-based metal organic framework material obtained in Example 3 is spherical in shape but has wrinkles on the surface, and the particle size ranges from 0.3 μm to 0.5 μm.

[0043] Example 4

[0044] S1: Take 0.2231g of manganese nitrate tetrahydrate and dissolve it in 20ml of anhydrous ethanol and deionized water in a ratio of 1:1 using a glass rod to obtain liquid A. Take 0.1055g of 1,3,5 - Use a glass plate to stir and dissolve benzenetricarboxylic acid in anhydrous ethanol: deionized water in a ratio of 1:1, a total of 20 ml of liquid to obtain liquid B;

[0045] S2: Pour liquid B into liquid A and stir at 100 r / min in a magnetic stirrer for 20 min. Then add the organic ligands 1, 3, 5 - The mixture was added with one equivalent of benzenetricarboxylic acid and sodium acetate and reacted at 160°C for 12 h in a tetrafluoroethylene-lined high-pressure reactor (50 ml). The resulting solution was washed three times with anhydrous ethanol by decantation and then dried in vacuum at 60°C for 12 h to obtain a manganese-based metal organic framework material.

[0046] The manganese-based metal organic framework material obtained in Example 4 has a sea urchin-like morphology and a particle size range of 10 μm to 15 μm.

[0047] Example 5

[0048] S1: Take 0.2231g of manganese nitrate tetrahydrate and dissolve it in 20ml of anhydrous ethanol with a glass rod to obtain liquid A. Take 0.1051g of 1,3,5 - The benzenetricarboxylic acid was dissolved in 20 ml of anhydrous ethanol by stirring with a glass plate to obtain solution B;

[0049] S2: Pour liquid B into liquid A and stir at 100 r / min in a magnetic stirrer for 20 min. Then add the organic ligands 1, 3, 5 - Two equivalents of trimellitic acid and acetic acid were added and the pH was adjusted to 5.9 with TEA. The mixture was reacted at 170°C for 12 h in a tetrafluoroethylene-lined high-pressure reactor (50 ml). The resulting solution was washed three times with anhydrous ethanol by decantation and then dried in vacuum at 60°C for 12 h to obtain a manganese-based metal organic framework material.

[0050] The morphology of the manganese-based metal organic framework material obtained in Example 5 is a mixture of octahedrons and irregular bodies, and the particle size ranges from 0.3 μm to 0.5 μm.

[0051] Example 6

[0052] S1: Take 0.2231g of manganese nitrate tetrahydrate and dissolve it in 20ml of anhydrous ethanol with a glass rod to obtain liquid A. Take 0.1050g of 1,3,5 - The benzenetricarboxylic acid was dissolved in 20 ml of anhydrous ethanol by stirring with a glass plate to obtain solution B;

[0053] S2: Pour liquid B into liquid A and stir at 100 r / min in a magnetic stirrer for 20 min. Then add the organic ligands 1, 3, 5 - Two equivalents of benzenetricarboxylic acid and acetic acid were reacted in a tetrafluoroethylene-lined high-pressure reactor (50 ml) at 170°C for 12 h. The resulting solution was washed three times with anhydrous ethanol by decantation and then dried in vacuum at 60°C for 12 h to obtain a manganese-based metal organic framework material.

[0054] The manganese-based metal organic framework material obtained in Example 6 has a smooth octahedron shape and a particle size range of 0.3 μm to 0.5 μm.

[0055] Example 7

[0056] S1: Take 0.2232g of manganese nitrate tetrahydrate and dissolve it in 1:1 anhydrous ethanol and deionized water with a glass rod to obtain a total of 20ml of liquid A. Take 0.1054g of 1,3,5 - Use a glass plate to stir and dissolve benzenetricarboxylic acid in anhydrous ethanol: deionized water in a ratio of 1:1, a total of 20 ml of liquid to obtain liquid B;

[0057] S2: Pour liquid B into liquid A and stir at 100 r / min in a magnetic stirrer for 20 min. Then add sodium acetate to the prepared standard solution to adjust the pH to 2.7, and react at 160°C in a tetrafluoroethylene-lined high-pressure reactor (50 ml) for 12 h. The resulting solution is washed three times with anhydrous ethanol by decantation and then dried in vacuum at 60°C for 12 h to obtain a manganese-based metal organic framework material.

[0058] The manganese-based metal organic framework material obtained in Example 7 has a rod-like morphology and a size length of 1 μm to 3 μm.

[0059] Example 8

[0060] S1: Dissolve 0.2231 g of manganese nitrate tetrahydrate in 15 ml of N, N using a glass rod. - Liquid A was obtained from dimethylformamide, and 0.1053 g of 1,3,5 - Tricarboxylic acid was dissolved in 15 ml N, N using a glass plate. - Liquid B was obtained in dimethylformamide;

[0061] S2: Pour liquid B into liquid A and stir at 100 r / min in a magnetic stirrer for 30 min. Then react at 120°C in a tetrafluoroethylene-lined autoclave (50 ml) for 12 h. The resulting solution is separated by decantation and separated by N, N - The manganese-based metal organic framework material was washed twice with dimethylformamide and anhydrous ethanol respectively and then dried in vacuum at 60°C for 12 hours.

[0062] The manganese-based metal organic framework material obtained in Example 8 is in the form of fibers, with a length of 30 μm to 50 μm.

[0063] Example 9

[0064] The specific operation is the same as that in Example 1, except that the high temperature reaction temperature is 180° C., and other reaction conditions and material composition remain unchanged, to obtain a manganese-based metal organic framework material, which is spherical in shape as in Example 1, and has a particle size range of 0.3 μm to 0.5 μm.

[0065] Example 10

[0066] The same as Example 4, except that three equivalents of the additive sodium acetate were added, and other reaction conditions and material compositions remained unchanged, to obtain a manganese-based metal organic framework material with a columnar shape and a size of 10 μm to 30 μm.

[0067] Embodiment 11

[0068] The same as Example 5, except that three equivalents of acetic acid as an additive were added, and other reaction conditions and material compositions remained unchanged, to obtain a manganese-based metal organic framework material in the form of spherical particles with a particle size range of 50 nm to 100 nm.

[0069] Example 12

[0070] The same as Example 5, except that four equivalents of acetic acid as an additive were added, and other reaction conditions and material compositions remained unchanged, to obtain a manganese-based metal organic framework material in the shape of an elongated cylinder with a length of 2 μm to 5 μm.

[0071] Comparative Example 1

[0072] The same as Example 1, except that the high temperature reaction temperature is 160° C., the mass of the manganese-based hydrated salt is 0.2259 g, the mass of the organic ligand is 0.1051 g, and the other reaction conditions and material composition remain unchanged, to obtain a manganese-based metal organic framework material, which has an octahedral morphology and a particle size range of 0.3 μm to 0.5 μm.

[0073] The regulating principle of the additives used in the present invention is that on the one hand, the additives compete with the multidentate linker for the metal coordination sites to produce a capping effect, thereby regulating the rate of skeleton extension and crystal growth. On the other hand, the additives can also affect the deprotonation process of the reaction by affecting the acid-base environment of the reaction system to determine the morphology of the final product.

[0074] On the one hand, the present invention uses acid-base additives to compete with multidentate linkers for metal coordination sites to achieve a capping effect, thereby adjusting the rate of framework extension and crystal growth. On the other hand, the additives can also affect the deprotonation process of the reaction by affecting the acid-base environment of the reaction system to determine the morphology of the final product, while controlling the reaction temperature and the type of solvent to affect the reaction rate to obtain manganese-based metal organic framework materials of different shapes and sizes.

Claims

1. A method for preparing a manganese-based metal organic framework material, characterized in that: The following steps are involved: S1: dissolving a manganese-based hydrated salt in an organic solvent to obtain a mixed solution A, and mixing an organic ligand and an organic solvent to obtain a mixed solution B; S2: Mixing the mixed solution B and the mixed solution A, stirring, adding additives, heating at high temperature, and separating, washing, and drying after the reaction to obtain a manganese-based metal organic framework material.

2. The method for preparing a manganese-based metal organic framework material according to claim 1, characterized in that: The manganese-based hydrated salt described in S1 is any one of manganese acetate tetrahydrate and manganese nitrate tetrahydrate, the mass ratio of the manganese-based hydrated salt to the organic solvent is 1:10, and the mass ratio of the organic ligand to the organic solvent is 1:

10.

3. The method for preparing a manganese-based metal organic framework material according to claim 1, characterized in that: The organic solvent described in S1 is any one or more of anhydrous ethanol, deionized water, N,N-dimethylformamide, and methanol.

4. The method for preparing a manganese-based metal organic framework material according to claim 1, characterized in that: The organic ligand described in S1 is any one or more of 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, and 1,2,3-benzenetricarboxylic acid.

5. The method for preparing a manganese-based metal organic framework material according to claim 1, characterized in that: The stirring time described in S2 is 20 min to 30 min, and the stirring speed is 200 r / min to 500 r / min.

6. The method for preparing a manganese-based metal organic framework material according to claim 1, characterized in that: The additive described in S2 is any one or more of acetic acid, sodium acetate, formic acid, sodium formate, and triethylamine.

7. The method for preparing a manganese-based metal organic framework material according to claim 1, characterized in that: The high temperature reaction temperature in S2 is 140° C. to 180° C., the reaction time is 12 h to 24 h, and the high temperature reaction process is carried out in a tetrafluoroethylene-lined high-pressure reactor.

8. The method for preparing a manganese-based metal organic framework material according to claim 1, characterized in that: The separation method is centrifugation, decantation, or filtration, preferably decantation. The drying temperature is 50° C. to 60° C., and the vacuum drying is maintained for 12 h to 24 h.

9. A manganese-based metal organic framework material obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The manganese-based metal organic framework material is a sea urchin-like structure.

10. A manganese-based metal organic framework material according to claim 9, characterized in that: The particle size range of the manganese-based metal organic framework material is 0.05 μm to 30 μm.

Images