A method for preparing Fe / Mn-MOF material suitable for large-scale production

Abstract

The application discloses a kind of preparation methods of Fe / Mn-MOF material suitable for large-scale production, iron salt is dissolved in solvent A, manganese salt is dissolved in solvent A, terephthalic acid is dissolved in solvent B;Three are respectively given into reaction container and mixed, heated stirring is carried out, after reaction, Fe / Mn-MOF is obtained by washing, drying;The molar ratio between iron salt, manganese salt, terephthalic acid is (0.9-1.1) :(0.9-1.1) :1, heating stirring temperature is controlled at 70-90 DEG C, reaction time is controlled at 50-80 min.The method of the application is under normal pressure condition, and the reaction process is safe and reliable;The application can control the product grain size and nucleation rate by adjusting the solvent ratio and stirring rate, and can adjust the product form according to market demand, and Fe / Mn-MOF can be quickly synthesized and prepared at a relatively low temperature of about 80 DEG C, which is suitable for large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of MOF material manufacturing, and particularly relates to a preparation method of Fe / Mn-MOF material. BACKGROUND

[0002] Metal-organic frameworks (MOFs) are porous crystalline materials formed by self-assembly of metal ions or metal clusters and organic ligands. The material has excellent performance of inorganic materials and organic materials. It not only has a high specific surface area, but also has good water stability and acid-base stability, which has attracted the research interest of many scholars. With its unique advantages, it is widely used in catalysis, gas adsorption, gas separation, sensors, drug delivery and other fields, especially for the adsorption and separation of toxic and harmful gases, which can solve some of the increasingly serious environmental problems faced by people. In addition, in the separation field, the preparation of composite MOFs materials with magnetism can be used for the adsorption and separation of toxic and harmful substances, heavy metals and the extraction and separation of target proteins in complex systems. The synthesis methods of MOFs mainly include solvothermal method, hydrothermal method, microwave method and ultrasonic assisted method. The existing synthesis method of Fe / Mn-MOF is mainly a hydrothermal reaction kettle synthesis method. This method has a long synthesis time, needs to be completed in a high-temperature and high-pressure reaction kettle, and the pressure in the container during the reaction process is uncontrollable, which often leads to poor repeatability of the results. Therefore, a method for rapidly and stably synthesizing Fe / Mn-MOF under normal pressure is invented.

[0003] For example, a synthesis method of rod-like MOF74(Mn) assembled by sheets disclosed in Chinese patent CN201911179183.7 includes dissolving 2,5-dihydroxyterephthalic acid and 50% manganese nitrate solution in a mixed solution of N,N-dimethylformamide, anhydrous ethanol and deionized water, transferring the mixed solution to a reaction kettle, and heating for a period of time. After the reaction is completed, the sheet-assembled rod-like manganese-based MOF is obtained by centrifugal washing and drying. The synthesis method obtains sheet-assembled rod-like manganese-based MOF by hydrothermal synthesis method. By adjusting the proportion of reactants, reaction solvent, reaction temperature and reaction time, the size and morphology of MOFs can be controlled. The prepared sheet-assembled rod-like MOF74(Mn) material can be used as a new catalytic material. The synthesis method is carried out at high temperature and high pressure, and has the problems of long reaction time, uncontrollable pressure in the container during the reaction process and poor repeatability of the results. SUMMARY

[0004] The present application aims at the technical problems of long preparation process, high reaction temperature and pressure, poor repeatability and difficult scale production of Fe / Mn-MOF material prepared by the existing hydrothermal reaction kettle synthesis method, and provides a preparation method of Fe / Mn-MOF material which can be carried out under normal pressure, has short reaction time, stable and controllable product quality and is suitable for scale production.

[0005] To achieve the above-mentioned purposes of the present application, the preparation method of Fe / Mn-MOF material suitable for scale production comprises the following steps: dissolving iron salt in solvent A, dissolving manganese salt in solvent A, and dissolving terephthalic acid in solvent B; then mixing and heating and stirring the three in a reaction container, and after reaction, washing and drying to obtain Fe / Mn-MOF; the molar ratio of the iron salt, manganese salt and terephthalic acid is (0.9-1.1) : 1, the heating and stirring temperature is controlled at 70-90 DEG C, and the reaction time is controlled at 50-80 min.

[0006]

[0007] Preferably, the solvent A is N,N-dimethylformamide, and the solvent B is acetonitrile.

[0008] Preferably, the iron salt is ferric chloride hexahydrate, and the manganese salt is manganese acetate tetrahydrate.

[0009] Preferably, the molar ratio of the iron salt, manganese salt and terephthalic acid is 1:1:1.

[0010] Preferably, the stirring rate is 250-400 rpm, and 320 rpm is preferred.

[0011] After a large number of experimental researches, the technical parameters of heating and stirring are optimized as follows: the heating and stirring temperature is 80 DEG C, the reaction time is 60 min, and the stirring rate is 320 rpm.

[0012] Compared with the prior art, the preparation method of Fe / Mn-MOF material suitable for scale production provides a special synthesis reaction environment for metal ions and organic ligands, and has the following beneficial effects:

[0013] (1) Compared with the traditional hydrothermal method, the preparation method of the present application is carried out under normal pressure, and the reaction process is safe and reliable.

[0014] (2) The preparation method of the present application can control the product grain size and nucleation rate by adjusting the solvent ratio and stirring rate, and can adjust the product form according to market demand.

[0015] ​(3) The preparation method can quickly synthesize and prepare Fe / Mn-MOF at a relatively low temperature of about 80 DEG C, and is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 SEM image of the Fe / Mn-MOF material obtained in Example 1 of the method of the application.

[0017] Figure 2 SEM image of the Fe-MOF material obtained in Comparative Example 1.

[0018] Figure 3 Particle size distribution graph of the Fe / Mn-MOF material obtained in Example 1 of the method of the application.

[0019] Figure 4 Particle size distribution graph of the Fe-MOF material obtained in Comparative Example 1. DETAILED DESCRIPTION

[0020] To describe the application, the following further describes in detail a preparation method of a Fe / Mn-MOF material suitable for large-scale production according to the application in combination with examples. The specific conditions not specified in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be purchased on the market. The protection scope of the application is not limited by the following examples.

[0021] Example 1

[0022] This example describes a synthesis method of Fe / Mn-MOF, which comprises the following steps:

[0023] (1) 0.0259 g of iron chloride hexahydrate was weighed and dissolved in 4 mL of N,N-dimethylformamide.

[0024] (2) 0.0173 g of manganese acetate tetrahydrate was weighed and dissolved in 4 mL of N,N-dimethylformamide.

[0025] (3) 0.0166 g of terephthalic acid was weighed and dissolved in 8 mL of acetonitrile.

[0026] (4) The solutions in (1), (2) and (3) were mixed, the molar ratio of iron chloride hexahydrate, manganese acetate tetrahydrate and terephthalic acid was close to 1:1:1, and the mixture was transferred into a glass beaker.

[0027] (5) The operation parameters of the magnetic stirring heating instrument were set as follows: temperature 80 DEG C, reaction time 60 min, stirring speed 320 rpm.

[0028] (6) The magnetic stirring rotor was placed in the sample, the temperature probe was connected, and the operation was started.

[0029] (7) Synthesis is completed, the sample is taken out, centrifuged, the separated solid is washed with ethanol three times, centrifuged three times, and the synthesized Fe / Mn-MOF is dried in a vacuum drying oven at 70°C to obtain the Fe / Mn-MOF material.

[0030] Comparative Example 1

[0031] This comparative example passes a synthesis method of Fe-MOF, comprising the following steps:

[0032] (1) 0.864 g of iron chloride hexahydrate is weighed and dissolved in 10 mL of N,N-dimethylformamide.

[0033] (2) 0.532 g of terephthalic acid is weighed and dissolved in 10 mL of N,N-dimethylformamide.

[0034] (3) The solutions in (1) and (2) are mixed, the molar ratio of iron chloride hexahydrate to terephthalic acid is close to 2:1, and the liquid is transferred into a polytetrafluoroethylene-lined reaction kettle, and the reaction kettle is placed into a forced air drying oven.

[0035] (4) The operation parameters of the forced air drying oven are set, the temperature is 150°C, the reaction time is 12 h, and the operation is started.

[0036] (5) Synthesis is completed, the sample is taken out, centrifuged, the separated solid is washed with ethanol three times, centrifuged three times, and the synthesized Fe-MOF is dried in a vacuum drying oven at 70°C to obtain the Fe-MOF material.

[0037] Example 2

[0038] This example passes a synthesis method of Fe / Mn-MOF, comprising the following steps:

[0039] (1) 0.0519 g of iron chloride hexahydrate is weighed and dissolved in 8 mL of N,N-dimethylformamide.

[0040] (2) 0.0346 g of manganese acetate tetrahydrate is weighed and dissolved in 8 mL of N,N-dimethylformamide.

[0041] (3) 0.0332 g of terephthalic acid is weighed and dissolved in 16 mL of acetonitrile.

[0042] (4) The solutions in (1) and (2) and (3) are mixed, the molar ratio of iron chloride hexahydrate to manganese acetate tetrahydrate to terephthalic acid is close to 1:1:1, and is transferred into a glass beaker.

[0043] (5) The operation parameters of the magnetic stirring heating instrument are set, the temperature is 80°C, the reaction time is 60 min, and the stirring rate is 320 rpm.

[0044] (6) Put the magnetic stirring rotor into the sample, connect the temperature probe, and start running.

[0045] (7) After the synthesis is completed, remove the sample, centrifugally separate, wash the separated solid with ethanol three times, centrifugally separate three times, and dry the synthesized Fe / Mn-MOF in a vacuum drying oven at 70°C to obtain the Fe / Mn-MOF material.

[0046] Example 3

[0047] This example discloses a method for synthesizing Fe / Mn-MOF, which comprises the following steps:

[0048] (1) Weigh 0.0519g of iron chloride hexahydrate and dissolve it in 7.5mL of N,N-dimethylformamide.

[0049] (2) Weigh 0.0346g of manganese acetate tetrahydrate and dissolve it in 7.5mL of N,N-dimethylformamide.

[0050] (3) Weigh 0.0332g of terephthalic acid and dissolve it in 15mL of acetonitrile.

[0051] (4) Mix the solutions in (1), (2) and (3), and move them into a glass beaker, so that the molar ratio of iron chloride hexahydrate, manganese acetate tetrahydrate and terephthalic acid is close to 1:1:1.

[0052] (5) Set the running parameters of the magnetic stirring heating instrument, temperature 80°C, reaction time 60min, stirring speed 320rpm.

[0053] (6) Put the magnetic stirring rotor into the sample, connect the temperature probe, and start running.

[0054] (7) After the synthesis is completed, remove the sample, centrifugally separate, wash the separated solid with ethanol three times, centrifugally separate three times, and dry the synthesized Fe / Mn-MOF in a vacuum drying oven at 70°C to obtain the Fe / Mn-MOF material.

[0055] The SEM image of the Fe / Mn-MOF material obtained by the method of Example 1 of the present application shown in FIG. 1 shows that the method of the present application can obtain Fe / Mn-MOF with smooth shuttle-shaped surface, uniform size and morphology, and uniform particle size distribution. Figure 1 The SEM image of the Fe-MOF material obtained by Comparative Example 1 shown in FIG. 2 shows that in the comparative example, the Fe-MOF has a typical spindle structure.

[0056] Figure 2 The SEM image of the Fe-MOF material obtained by Comparative Example 1 shown in FIG. 2 shows that in the comparative example, the Fe-MOF has a typical spindle structure.

[0057] The SEM image of the Fe-MOF material obtained by Comparative Example 1 shown in FIG. 2 shows that in the comparative example, the Fe-MOF has a typical spindle structure. Figure 3 Figure 4 ​​It can be known that, under the same ratio of metal ions and organic ligands, the method for preparing Fe / Mn-MOF in the application has smaller particle size (D Fe-MOF ≈200D Fe / Mn-MOF ) of the obtained material, perfect morphology, perfect crystallinity, complete reaction and almost no impurities on the surface compared with the general hydrothermal method for preparing MOF.

[0058] The SEM images of the Fe / Mn-MOF materials obtained in the method embodiments 2 and 3 are similar to that in the embodiment 1.

Claims

1. A method for preparing Fe / Mn-MOF materials suitable for large-scale production, characterized in that The method comprises the following steps: dissolving an iron salt in solvent A, dissolving a manganese salt in solvent A, and dissolving terephthalic acid in solvent B; respectively introducing the three into a reaction container for mixing, heating, and magnetic stirring; and after reaction, washing and drying to obtain Fe / Mn-MOF; the molar ratio of the iron salt, manganese salt, and terephthalic acid is (0.9-1.1):(0.9-1.1):1, the temperature for heating and magnetic stirring is controlled at 70-90°C, the reaction time is controlled at 50-80 minutes, and the stirring rate is 250-400 rpm; the solvent A is N,N-dimethylformamide; and the solvent B is acetonitrile.

2. The method for preparing a Fe / Mn-MOF material suitable for large-scale production according to claim 1, characterized in that: The iron salt is ferric chloride hexahydrate.

3. The method for preparing a Fe / Mn-MOF material suitable for large-scale production according to claim 1, characterized in that: The manganese salt is manganese acetate tetrahydrate.

4. The method for preparing a Fe / Mn-MOF material suitable for large-scale production according to claim 1, wherein: The iron salt is ferric chloride hexahydrate; the manganese salt is manganese acetate tetrahydrate; and the molar ratio of the iron salt, the manganese salt and terephthalic acid is 1:1:

1.

5. The method for preparing a Fe / Mn-MOF material suitable for large-scale production according to claim 4, characterized in that: The heating and stirring temperature was 80° C., the reaction time was 60 min, and the stirring rate was 320 rpm.

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