Controllable synthesis method of aluminum-based metal organic framework compound based on modulator

Abstract

The invention discloses a controllable synthesis method of an aluminum-based metal organic framework compound based on a modulator, and belongs to the field of nano material preparation. According to the controllable synthesis method, a soluble aluminum salt is used as an aluminum source, a polycarboxylic acid compound or a salt or a derivative thereof is used as an organic ligand, and an organic acid or a polar solvent is used as a conditioning agent, so that controllable synthesis of the shape and the size of the aluminum-based metal organic framework compound is realized. The controllable synthesis method disclosed by the invention has the characteristics of mild synthesis conditions, short reaction period, simplicity in operation and the like, and the obtained Al-MOF can meet different application scenes such as the fields of adsorption separation, gas storage, catalysis, drug loading, energy and the like due to different morphology and size characteristics of the Al-MOF.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of nanomaterials, and particularly relates to a method for controllable synthesis of an aluminum-based metal-organic framework compound. Background Art

[0002] Metal-organic framework compounds (MOFs) are porous materials assembled from metal ions or ion clusters and organic ligands. Due to their high porosity, large specific surface area, and adjustable chemical composition, they are widely used in the fields of adsorption separation, gas storage, catalysis, drug loading, etc. Currently, more than 100,000 kinds of MOF materials have been synthesized, but only a few can be commercially applied. Aluminum-based MOF (Al-MOF) is considered to be a kind of MOF material with great commercial potential because of its stable structure and low cost of aluminum salts.

[0003] Currently, the preferred synthesis method for large-scale preparation is the co-precipitation method. For example, a synthesis method of aluminum fumarate disclosed by BASF (CN103140495A) places aluminum compounds and fumaric acid in an alkaline aqueous medium system and reacts at a reaction temperature of 20-100 °C for 0.2-4 h to obtain a crude product. This method has mild synthesis conditions and high yield, and has good industrialization potential. Subsequently, some scholars have made some explorations on the synthesis method disclosed in this patent (E. Alvarez, N. Guillou, C. Martineau, et al., Angew. Chem. Int. Ed. 2015, 54, 3664-3668; F. Jeremias, D. Frohlich, C. Janiak, et al., RSC Adv., 2014, 4, 24073-24082), but the overall technical solution is still within the technical scope defined by the BASF patent. Through research, it is found that although the space-time yield of this typical synthesis route disclosed by BASF is high, due to the fast reaction, the morphology and size of the product are not controlled. The obtained primary particles will aggregate to form agglomerated secondary particles, and a large amount of accumulation of secondary particles will also occur, resulting in a series of problems such as difficult dispersion of the material, too large particle size range, difficult processing, and unstable product performance in the subsequent engineering application process, which seriously hinders the commercial promotion of this material.

[0004] In summary, there is still an urgent need to explore a technical solution for controllable synthesis of the microscopic morphology and particle size of Al-MOF. Summary of the Invention

[0005] In view of the above deficiencies in the synthesis of Al-MOF by the existing co-precipitation technology, the present invention provides a controllable synthesis method of an aluminum-based metal-organic framework compound based on a modulator, aiming to regulate the coordination process of aluminum ions and organic ligands by adding a modulator, such as by adding a competitor of the organic ligand to change the crystal growth rate, thereby controlling the morphology and size of the Al-MOF product during the synthesis process.

[0006] To achieve the above invention object, the present invention adopts the following technical solutions.

[0007] The present invention provides a controllable synthesis method of an aluminum-based metal-organic framework compound based on a modulator, wherein the "controllable" means that during the process of the synthesis method, the microscopic morphology and size of the synthesis product, i.e., the aluminum-based metal-organic framework compound, are regulated by changing the synthesis conditions. The synthesis method adopts the co-precipitation method, and by adding the modulator to the metal ion solution and / or the organic ligand solution, the coordination process of aluminum ions and organic ligands is regulated, and the crystal growth rate during the co-precipitation reaction is changed to control the microscopic morphology and size of the aluminum-based metal-organic framework compound.

[0008] More specifically, the synthesis method includes the following steps:

[0009] (1) Dissolve a soluble aluminum salt in a first solvent to form the metal ion solution, i.e., solution A.

[0010] (2) Dissolve an organic ligand and a basic auxiliary agent in a second solvent in a certain proportion to form the organic ligand solution, i.e., solution B.

[0011] (3) Add a modulator to at least one of solution A and solution B and mix them evenly.

[0012] (4) Mix the above two obtained solutions evenly and react for a certain time under a set temperature condition.

[0013] (5) Collect the product obtained in step (4), and then carry out washing, separation and drying.

[0014] Furthermore, the aluminum salt used in step (1) includes one or more mixtures of aluminum salts of halides, aluminum salts of inorganic oxyacids, and their hydrate forms; preferably, the aluminum salt is an aluminum chloride salt, an aluminum nitrate salt, an aluminum sulfate salt, an aluminum phosphate salt, and their hydrate forms; more preferably, the aluminum salt is aluminum sulfate octadecahydrate, aluminum chloride hexahydrate, aluminum nitrate nonahydrate.

[0015] Further, the organic ligand is one or more of at least dibasic carboxylic acid organic compounds, or their salts, or their derivatives; preferably, the organic ligand is selected from fumaric acid, terephthalic acid, isophthalic acid, and trimesic acid; more preferably, the organic ligand is selected from one of fumaric acid and terephthalic acid.

[0016] Further, the basic auxiliary agent is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonia water, urea, methylamine, ethylamine, propylamine, butylamine, diethylamine, dipropylamine, dibutylamine, and triethylamine; preferably, the basic auxiliary agent is selected from one or more of sodium hydroxide, potassium hydroxide, and urea; more preferably, the basic auxiliary agent is sodium hydroxide.

[0017] Further, both the first solvent and the second solvent are water.

[0018] Further, the conditioner is selected from one or more of organic acids, alcohols, ketones, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), acetonitrile, toluene, benzene, chlorobenzene, and pyridine; preferably, the organic acids are selected from one or more of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, benzoic acid, salicylic acid, caffeic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid; preferably, the alcohols are selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, pentanol, and hexanol.

[0019] Further, the ratio of the amounts of the aluminum salt, organic ligand, and basic auxiliary agent added in steps (1) and (2) satisfies: the molar ratio of aluminum ions, organic ligand, and basic auxiliary agent is 1:1:1.5 - 2.5; preferably, the molar ratio of aluminum ions, organic ligand, and basic auxiliary agent is 1:1:2.

[0020] Further, the ratio of the total weight of the aluminum salt and organic ligand used for the reaction to the total weight of the first solvent and the second solvent is 5% - 25%.

[0021] Further, the addition amount of the organic acid conditioner is 0.5% - 20% of the molar amount of the organic ligand added; preferably, the addition amount of the organic acid conditioner is 0.5% - 5% of the molar amount of the organic ligand added; more preferably, the addition amount of the organic acid conditioner is 0.5% - 1% of the molar amount of the organic ligand added.

[0022] Further, for the other conditioners except organic acids, their addition amount is 1% - 20% of the total volume of the first solvent and the second solvent; preferably, the addition amount of the other conditioners accounts for 5% - 15% of the total volume of the first solvent and the second solvent.

[0023] Further, the reaction temperature is 40°C - 100°C; preferably, the reaction temperature is 60°C - 80°C.

[0024] Further, the reaction time is 2 - 12 h. Preferably, the reaction time is 8 - 12 h.

[0025] Further, there is no limitation on the implementation methods of the separation, cleaning, and drying processes, as long as the purposes of each process link can be achieved. Preferably, the cleaning process is repeated multiple times in the order of water and organic solvents. The organic solvents are preferably methanol, ethanol, and DMF, and the number of cleaning times is preferably 2 - 3 times respectively. Preferably, the drying temperature is 60 - 120°C and the drying time is 1 - 12 h.

[0026] Further, in steps (1) - (5), when it comes to the processes of dissolution and reaction, the process can be accelerated by stirring, and the specific stirring method is not limited.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The morphology and particle size of the Al-MOF obtained by the synthesis method of the present invention are controllable, and the particle size distribution range is narrow.

[0029] (2) The Al-MOF obtained by the synthesis method of the present invention has good dispersibility and no obvious agglomeration phenomenon. Description of the Drawings

[0030] Figure 1 It is the scanning electron microscope (SEM) image of the aluminum-based metal-organic framework compounds prepared in Example 1 and Example 2 of the present invention.

[0031] Figure 2 It is the SEM image of the aluminum-based metal-organic framework compounds prepared in Examples 4 - 7 of the present invention.

[0032] Figure 3 It is the SEM image of the aluminum-based metal-organic framework compounds prepared in Example 4, Example 9, and Example 10 of the present invention.

[0033] Figure 4 It is the SEM image of the aluminum-based metal-organic framework compounds prepared in Example 3, Example 8, and Comparative Example 1 of the present invention.

[0034] Figure 5 It is the SEM image of the aluminum-based metal-organic framework compounds prepared in Example 1 and Comparative Example 2 of the present invention.

[0035] Figure 6 It is the SEM image of the aluminum-based metal-organic framework compounds prepared in Example 4 and Comparative Example 3 of the present invention. Detailed Embodiments

[0036] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and essence of the present invention, all other contents obtained by making several equivalent improvements and simple modifications to the present invention belong to the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0037] Example 1

[0038] In this example, an alcohol modulator was used. The specific process steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0039] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate and place it in a glass container. Add 45 mL of deionized water and stir to dissolve it completely to form solution A.

[0040] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid and 2.46 g (61.6 mmol) of sodium hydroxide respectively and place them in another glass container. Add 45 mL of deionized water, stir well to form solution B, and cool it to room temperature.

[0041] (3) Add 5 mL of n-butanol to solution A and solution B respectively, and stir for 30 min.

[0042] (4) Mix the two obtained solutions, stir evenly, and react at 80 °C for 12 h.

[0043] (5) Centrifuge and collect the obtained product, and wash it 3 times with deionized water, DMF, and absolute ethanol respectively. Then place the washed product in a vacuum drying oven and react at 80 °C for 6 h to obtain the aluminum-based metal-organic framework compound (Al-MOF).

[0044] Example 2

[0045] Compared with Example 1, the dosage of the alcohol modulator was adjusted in this example. The specific process steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0046] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate and place it in a glass container. Add 45 mL of deionized water and stir to dissolve it completely to form solution A.

[0047] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid and 2.46 g (61.6 mmol) of sodium hydroxide respectively and place them in another glass container. Add 45 mL of deionized water, stir well to form solution B, and cool it to room temperature.

[0048] (3) Add 2.5 mL of n-butanol to solution A and solution B respectively, and stir for 30 min.

[0049] (4) Mix the two obtained solutions, stir evenly, and react at 80 °C for 12 h.

[0050] (5) Centrifuge and collect the obtained product, and wash it 3 times with deionized water, DMF and absolute ethanol respectively. Then place the washed product in a vacuum drying oven and react at 80 °C for 6 h to obtain an aluminum-based metal-organic framework compound (Al-MOF).

[0051] Example 3

[0052] Compared with Example 1, the coprecipitation reaction temperature was adjusted in this example, that is, the reaction temperature in step (4) was set to 60 °C, and the rest was the same as in Example 1.

[0053] Example 4

[0054] In this example, oxalic acid, an organic acid, was used as the modulator and was added separately to solution B. The specific process steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0055] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate and place it in a glass container. Add 50 mL of deionized water and stir to dissolve it completely to form solution A.

[0056] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid, 2.46 g (61.6 mmol) of sodium hydroxide and 0.028 g (0.31 mmol) of oxalic acid respectively and place them in another glass container. Add 50 mL of deionized water, stir well to form solution B, and cool to room temperature.

[0057] (4) Mix the two obtained solutions, stir evenly, and react at 80 °C for 12 h.

[0058] (5) Centrifuge and collect the obtained product, and wash it 3 times with deionized water and absolute ethanol respectively. Then place the washed product in a vacuum drying oven and react at 80 °C for 6 h to obtain an aluminum-based metal-organic framework compound (Al-MOF).

[0059] Example 5

[0060] In this example, the amount of oxalic acid used as the modulator in Example 4 was adjusted. The specific process steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0061] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate and place it in a glass container. Add 50 mL of deionized water and stir to dissolve it completely to form solution A.

[0062] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid, 2.46 g (61.6 mmol) of sodium hydroxide, and 0.014 g (0.156 mmol) of oxalic acid separately into another glass container, add 50 mL of deionized water, stir well to form solution B, and cool to room temperature.

[0063] (4) Mix the two obtained solutions, stir evenly, and react at 80 °C for 12 h.

[0064] (5) Centrifuge and collect the obtained product, and wash it 3 times with deionized water and anhydrous ethanol respectively. Then place the washed product in a vacuum drying oven and react at 80 °C for 6 h to obtain an aluminum-based metal-organic framework compound (Al-MOF).

[0065] Example 6

[0066] Compared with Example 4 and Example 5, in this example, the addition amount of oxalic acid in step (2) is adjusted to 0.056 g (0.62 mmol), and the rest remains unchanged.

[0067] Example 7

[0068] Compared with Example 4 and Example 5, in this example, the addition amount of oxalic acid in step (2) is adjusted to 0.139 g (1.54 mmol), and the rest remains unchanged.

[0069] Example 8

[0070] In this example, the temperature of the coprecipitation reaction in Example 4 is adjusted, that is, the reaction temperature in step (4) is set to 60 °C, and the rest is the same as in Example 4.

[0071] Example 9

[0072] In this example, salicylic acid in organic acids is used as the modulator and is added to solution B alone. The specific process steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0073] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate into a glass container, add 50 mL of deionized water, and stir to dissolve it completely to form solution A.

[0074] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid, 2.46 g (61.6 mmol) of sodium hydroxide, and 0.31 mmol of salicylic acid separately into another glass container, add 50 mL of deionized water, stir well to form solution B, and cool to room temperature.

[0075] (4) Mix the two obtained solutions, stir evenly, and react at 80 °C for 12 h.

[0076] (5) The obtained product was collected by centrifugation and washed three times with deionized water and anhydrous ethanol respectively. Then the washed product was placed in a vacuum drying oven and reacted at 80 °C for 6 h to obtain an aluminum-based metal-organic framework compound (Al-MOF).

[0077] Example 10

[0078] In this example, malonic acid in organic acids was used as the modifier and was added separately to solution B. The specific process steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0079] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate and place it in a glass container. Add 50 mL of deionized water and stir to dissolve it completely to form solution A.

[0080] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid, 2.46 g (61.6 mmol) of sodium hydroxide, and 0.31 mmol of malonic acid respectively and place them in another glass container. Add 50 mL of deionized water, stir well to form solution B, and cool it to room temperature.

[0081] (4) Mix the two obtained solutions, stir evenly, and react at 80 °C for 12 h.

[0082] (5) The obtained product was collected by centrifugation and washed three times with deionized water and anhydrous ethanol respectively. Then the washed product was placed in a vacuum drying oven and reacted at 80 °C for 6 h to obtain an aluminum-based metal-organic framework compound (Al-MOF).

[0083] The display of the above examples is only to illustrate the principle of the present invention. They are only some of the preferred embodiments explored by the inventor in the technical solutions of the present invention. In the repeated implementation exploration results of the inventor, it is found that on the basis of the above examples, by adjusting certain process parameters within an appropriate range, aluminum-based metal-organic framework compounds with technical effects equivalent to those of the above examples can also be obtained, achieving the purpose of the present invention. These process parameters and their adjustment ranges include: (1) The molar ratio of the raw materials added in the coprecipitation reaction satisfies that the molar ratio of aluminum ions, organic ligands, and basic assistants is within the range of 1:1:1.5 - 2.5; (2) The total weight of the aluminum salt and the organic ligand accounts for 5% - 25 wt% of the total weight of the solvent; (3) The addition amount of the organic acid modifier is within the range of 0.5% - 20% of the molar amount of the organic ligand added; (4) The addition amount of other modifiers except organic acids is 1% - 20% of the total volume of the solvent; (5) The coprecipitation reaction temperature is 40 °C - 100 °C, and the reaction time is within the range of 2 - 12 h. Any combination and adjustment of the parameters listed here within their ranges can prepare an Al-MOF material with adjustable microstructure, good uniformity of nanoparticle size, and good dispersion of primary nanoparticles.

[0084] Comparative Example 1

[0085] In this comparative example, no modulator was used, and the coprecipitation reaction temperature was 60°C. The specific steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0086] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate and place it in a glass container. Add 45 mL of deionized water and stir to dissolve it completely to form Solution A.

[0087] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid and 2.46 g (61.6 mmol) of sodium hydroxide respectively and place them in another glass container. Add 45 mL of deionized water, stir well to form Solution B, and cool it to room temperature.

[0088] (3) Mix the two solutions, stir evenly, and react at 60°C for 12 h.

[0089] (4) Centrifuge and collect the obtained product, and wash it 3 times with deionized water, DMF, and absolute ethanol respectively. Then place the washed product in a vacuum drying oven and react at 80°C for 6 h to obtain the aluminum-based metal-organic framework compound.

[0090] Comparative Example 2

[0091] In this comparative example, the same modulator as in Example 1 was used, but the coprecipitation reaction temperature was adjusted to room temperature, and the rest remained unchanged. The specific steps for preparing the aluminum-based metal-organic framework compound are as follows.

[0092] (1) Weigh 10.3 g (15.4 mmol) of aluminum sulfate octadecahydrate and place it in a glass container. Add 45 mL of deionized water and stir to dissolve it completely to form Solution A.

[0093] (2) Weigh 3.6 g (30.8 mmol) of fumaric acid and 2.46 g (61.6 mmol) of sodium hydroxide respectively and place them in another glass container. Add 45 mL of deionized water, stir well to form Solution B, and cool it to room temperature.

[0094] (3) Add 5 mL of n-butanol to Solution A and Solution B respectively, and stir for 30 min.

[0095] (4) Mix the two solutions, stir evenly, and react at room temperature for 12 h.

[0096] (5) Centrifuge and collect the obtained product, and wash it 3 times with deionized water, DMF, and absolute ethanol respectively. Then place the washed product in a vacuum drying oven and react at 80°C for 6 h to obtain the aluminum-based metal-organic framework compound (Al-MOF).

[0097] Comparative Example 3

[0098] In this comparative example, the same modulator as in Example 4 was used and the dosage was also the same. However, the co-precipitation reaction temperature was adjusted to room temperature, and the rest was the same as in Example 4.

[0099] The microscopic morphologies of the aluminum-based metal-organic framework compound Al-MOF prepared in each example and comparative example were obtained by scanning electron microscopy technology, and the results are presented in the appendix Figure 1-6 .

[0100] Among them, Figure 1 Figures (a) and (b) in [reference] are the SEM results of the Al-MOF prepared in Example 1 and Example 2 respectively. It can be seen that the Al-MOF materials prepared in Example 1 and Example 2 both exhibit a nano-sheet structure, the nano-particle sizes are relatively uniform, and the particle sizes are basically distributed between 30 nm and 120 nm, and they are well-dispersed. They are all uniformly dispersed primary particles, and there is no agglomeration phenomenon where primary particles aggregate to form secondary particles.

[0101] Figure 2 Figures (a), (b), (c), and (d) in [reference] are the SEM images of the Al-MOF prepared in Example 4, Example 5, Example 6, and Example 7 respectively, which correspond to the Al-MOF prepared with different addition amounts of oxalic acid modulator. It can be seen from the comparison of the figures that within a certain range of oxalic acid addition amount, the morphology and size uniformity of Al-MOF can be controlled (such as Figure 2 Figures (a) and (b) in [reference], that is, Example 4 and Example 5), while when the oxalic acid addition amount is too large (such as Example 6 and Example 7), the uniformity will decrease, and there will be agglomeration of nano-particles, forming agglomerated large-sized secondary or even multiple nano-particles, such as Figure 2 Figures (c) and (d) in [reference].

[0102] Figure 3 Figures (a), (b), and (c) in [reference] correspond to the SEM results of the Al-MOF prepared in Example 4, Example 9, and Example 10 respectively. Different modulators were used in the three examples. Example 4, Example 9, and Example 10 used oxalic acid, salicylic acid, and malonic acid respectively. It can be seen from the figures that the microscopic morphologies and sizes of the materials prepared with different modulators will be different, which may be due to the different regulation effects of different modulators on the coordination process of aluminum ions and organic ligands during the coordination reaction, as well as the different effects on the crystal growth rate; but obviously, by controlling the reaction conditions and the addition amounts of each modulator, the uniformity of the microscopic morphology and size of the product and the dispersion of nano-particles can be effectively controlled.

[0103] Figure 4Figures (a), (b) and (c) respectively correspond to the SEM results of the Al-MOF prepared in Example 3, Example 8 and Comparative Example 1. It can be seen from the figures that the modulator plays an important role in the morphology and size of the synthesized Al-MOF. Although different modulators are used in Example 3 and Example 8, each modulator effectively controls the microstructure of Al-MOF, showing uniform nanoparticle size, good dispersion and no agglomeration. Figure 4 (c) shows the case of Comparative Example 1 without using a modulator, indicating that in the absence of a modulator, the morphology of Al-MOF is extremely irregular, the particle size range is extremely large, and the particle dispersion effect is poor. Basically, no dispersed primary nanoparticles can be seen, and obvious multiple agglomeration phenomena occur. After agglomeration, the size reaches the micron level.

[0104] Figure 5 Figures (a) and (b) in Figure 6 Figures (a) and (b) in are respectively the SEM results of the Al-MOF prepared in Example 1, Comparative Example 2, Example 4 and Comparative Example 3. By pairwise comparison, it can be seen that in the presence of a modulator, different reaction temperatures have a great impact on the product morphology and size. Figure 5 (b) and Figure 6 (b) show that under the condition of adding a modulator and room temperature synthesis, the primary nanoparticles of Al-MOF also show a sheet-like morphology, but the product dispersion is not good. The primary nanoparticles agglomerate into spherical secondary nanoparticles, and the aggregates formed by the spherical secondary nanoparticles aggregate into larger irregular blocks, resulting in extremely uneven physical properties of the product, which is not conducive to subsequent applications. Obviously, under the action of the modulator, by optimizing the synthesis temperature parameters, such as Example 1 and Example 4 (corresponding to Figure 5 Figure (a) in Figure 6 Figure (b) in ), the microstructure of Al-MOF is controlled, and the nanoparticles show a uniform size, dispersed and non-agglomerated morphology, indicating that the modulator and appropriate reaction temperature can effectively control the microstructure of the synthesized product.

[0105] In summary, a controllable synthesis method of an aluminum-based metal-organic framework compound based on a modulator according to the present invention changes the coordination environment by using a modulator (such as a ligand competitor, a polar solvent, etc.), regulates the synthesis rate and crystal morphology, and finally realizes the uniformity and good dispersion of the product morphology and size by optimizing other reaction conditions, so as to ensure good consistency of the physical properties of the MOF material during subsequent applications and expand the applicability of the material.

Claims

1. A controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator, characterized in that: The controllable synthesis method adopts a coprecipitation method, by adding the modulator to the metal ion solution and / or the organic ligand solution, adjusting the coordination process of aluminum ions and organic ligands, changing the growth rate of crystals during the coprecipitation reaction, so as to control the microscopic morphology of the aluminum-based metal organic framework compound; the microscopic morphology at least includes the particle size distribution of the aluminum-based metal organic framework compound nanoparticles and the dispersed morphology of the nanoparticles.

2. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 1, characterized in that: The modulator is selected from one or more of organic acids, alcohols, ketones, dimethyl sulfoxide, N,N-dimethylformamide, N,N-diethylformamide, acetonitrile, toluene, benzene, chlorobenzene, and pyridine.

3. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 2, characterized in that: The synthesis method comprises the following steps: 1) dissolving a soluble aluminum salt in a first solvent to form the metal ion solution, i.e., solution A; 2) dissolving the organic ligand and the alkaline auxiliary agent in a second solvent in a certain proportion to form the organic ligand solution, i.e., solution B; 3) adding the modulator to at least one of solution A and solution B, and uniformly mixing the modulator in the solution; 4) mixing the two solutions obtained above evenly and reacting them at a certain reaction temperature for a certain time; 5) collecting the product obtained in step 4), and then washing, separating and drying it to obtain the aluminum-based metal organic framework compound.

4. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 3, characterized in that: The aluminum salt is a mixture of one or more of an aluminum salt of a halide, an aluminum salt of an inorganic oxygen-containing acid, and a hydrate thereof.

5. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 3, characterized in that: The organic ligand is at least one or more of a dicarboxylic acid organic compound, or a salt thereof, or a derivative thereof; the alkaline auxiliary agent is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonia water, urea, methylamine, ethylamine, propylamine, butylamine, diethylamine, dipropylamine, dibutylamine and triethylamine; and the first solvent and the second solvent are both water.

6. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 3, characterized in that: The ratio of the aluminum salt, the organic ligand and the alkaline auxiliary agent satisfies that the molar ratio of the aluminum ion, the organic ligand and the alkaline auxiliary agent is 1:1:1.5-2.

5.

7. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 3, characterized in that: The ratio of the total weight of the aluminum salt and the organic ligand to the total weight of the first solvent and the second solvent is 5-25%.

8. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 3, characterized in that: When the modulator is an organic acid, its added amount accounts for 0.5-20% of the molar amount of the organic ligand added; when the modulator is other modulators other than organic acids, its added amount accounts for 1-20% of the total volume of the first solvent and the second solvent.

9. The controllable synthesis method of aluminum-based metal organic framework compounds based on a modulator according to claim 3, characterized in that: In step 4), the reaction temperature is 40°C-100°C; the reaction time is 2-12h.

10. An aluminum-based metal organic framework compound synthesized by the synthesis method according to any one of claims 1 to 9, characterized in that: The microscopic morphology of the aluminum-based metal organic framework compound shows that the nanoparticles have uniform particle size distribution, the particle size distribution is between 30-120 nm, and the primary nanoparticles are in a non-agglomerated dispersed state.

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