A covalent organic framework material and preparation method thereof

Abstract

The present invention discloses a covalent organic framework material and a preparation method thereof, and belongs to the field of porous organic framework materials. The technical scheme includes using chiral ammonia unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid as raw materials, and adopting a three-component one-pot Doebner reaction to prepare a covalent organic framework material containing a quinoline-4-carboxylic acid structural unit. The present invention is applied to the preparation of porous organic framework materials, and solves the technical problems that the existing chiral COF materials have low crystallinity and poor stability, and are prone to losing chiral characteristics or structural integrity during solvent thermal synthesis or in extreme chemical environments, and retains the chiral characteristics while also enhancing the structural robustness.

Description

Technical Field

[0001] The invention belongs to the field of porous organic framework materials, and in particular relates to a covalent organic framework material and a preparation method thereof. Background Art

[0002] Covalent organic frameworks (COFs) have permanent porosity, highly ordered and extended structures, good chemical stability, and adjustable functionality, which makes them have important application prospects in catalysis, separation, sensing, nanomedicine, etc. However, traditional COF materials are mostly connected by dynamic reversible bonds such as imine bonds, and have poor stability in strong acid, strong base or reducing chemical environments.

[0003] In order to expand the bonding types of COF materials and improve their chemical stability, more and more linking units and construction methods have been reported. In order to make the synthesis method of covalent organic frameworks (COFs) more perfect, it is an urgent problem to develop new synthesis methods, construct COF materials with high chemical stability, and use potential functionalization sites in the skeleton to achieve functionalization and efficient application in harsh chemical environments. As an important branch of COF, chiral covalent organic framework materials not only inherit the excellent properties of COF, but also have application potential in small molecule recognition, asymmetric catalysis, chiral separation and other fields due to their unique chiral structure.

[0004] However, how to effectively construct stable chiral COF materials with high crystallinity remains a challenging scientific problem. Summary of the invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to overcome the technical problems of low crystallinity and poor stability of existing chiral COF materials, and easy loss of chiral characteristics or structural integrity during solvent thermal synthesis or in extreme chemical environments, and propose a covalent organic framework material and a preparation method thereof that retains chiral characteristics while enhancing structural robustness.

[0006] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0007] On the one hand, the present invention provides a method for preparing a covalent organic framework material, comprising: using chiral ammonia unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid as raw materials, and adopting a three-component one-pot Doebner reaction to prepare a covalent organic framework material containing a quinoline-4-carboxylic acid structural unit.

[0008] Preferably, the molar ratio of the chiral amino unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid is 1:1.5:3-6.

[0009] Preferably, the molar ratio of the chiral amino unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid is 1:1.5:3.6.

[0010] Preferably, the method specifically comprises: using chiral ammonia unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid as raw materials in a reaction solvent, reacting at room temperature for 3-7 days in the presence of a catalyst to obtain the covalent organic framework material containing quinoline-4-carboxylic acid structural units.

[0011] Preferably, the reaction solvent is selected from any one of acetonitrile, dioxane, and DMF; and the catalyst is selected from any one of p-toluenesulfonic acid, acetic acid, and aminosulfonic acid.

[0012] Preferably, the reaction solvent is acetonitrile; the catalyst is acetic acid; and the reaction is carried out at room temperature for 7 days.

[0013] Preferably, the method further comprises: after the reaction is completed, the crude product is centrifuged, washed in ethanol, tetrahydrofuran and acetone in sequence, and vacuum dried to obtain the borax covalent organic framework material containing quinoline-4-carboxylic acid structural units.

[0014] Preferably, the drying temperature is 60° C. and the drying time is 24 h.

[0015] Preferably, the chiral ammonia unit TAPB-Pyr is prepared by the following method:

[0016] A mixture of tribromotoluene, N-bromosuccinimide, azobisisobutyronitrile and carbon tetrachloride was refluxed and stirred for 1 hour; NBS was then added to the reactant solution, and the reflux reaction was continued for 3 hours, and the solvent was removed in vacuo to obtain product A;

[0017] At 0°C, NaH was added to a dry THF solution of Boc-L-prolinol, stirred for 1 h, and then the product A was added to the mixture. After reacting for 6 h, the mixture was extracted with ethyl acetate, the organic layer was collected, dried over anhydrous sodium sulfate, and the solvent was removed in vacuo to obtain a crude product of B;

[0018] The crude product of B and 4-aminophenylboronic acid pinacol ester are dissolved in ethylene glycol dimethyl ether, and potassium carbonate aqueous solution is added under a nitrogen atmosphere, and then tetrakis(triphenylphosphine)palladium is added, and the mixture is refluxed for 48 hours. After cooling, the mixture is extracted with ethyl acetate, and the organic layer is collected and dried over anhydrous sodium sulfate. The solvent is removed in vacuo, and the mixture is purified by column chromatography to obtain product C;

[0019] The product C is dissolved in dichloromethane, trifluoroacetic acid is added at 0°C, and then stirred at room temperature for 3 h. The solvent is removed in vacuo, and water is added to clear the mixture. Then, NaHCO3 solution is added until a large amount of turbidity is generated. The mixture is extracted with ethyl acetate, the organic layer is collected, and dried over anhydrous sodium sulfate. The solvent is removed in vacuo to obtain the chiral amino unit TAPB-Pyr.

[0020] Another aspect of the present invention provides a covalent organic framework material prepared by the method for preparing a covalent organic framework material according to any of the above technical solutions.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a method for preparing a covalent organic framework material. A novel chiral covalent organic framework material with high chemical stability and containing a quinoline-4-carboxylic acid linking unit is synthesized by a three-component one-pot Doebner reaction at room temperature. The method is simple to operate, green and efficient, and expands the construction mode and diversity of chiral COF materials. While retaining the chiral characteristics of the covalent organic framework material, the robustness of the structure is also enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is A in Example 1 of the present invention 1 H-NMR spectrum;

[0024] Figure 2 is A in Example 1 of the present invention 13 C-NMR spectrum;

[0025] Figure 3 is C in Example 1 of the present invention 1 H-NMR spectrum;

[0026] Figure 4 is C in Example 1 of the present invention 13 C-NMR spectrum;

[0027] Figure 5 is the TAPB-Pyr in Example 1 of the present invention 1 H-NMR spectrum;

[0028] Figure 6 is the TAPB-Pyr in Example 1 of the present invention 13 C-NMR spectrum;

[0029] Figure 7 is the infrared spectrum of CCOF-COOH in Example 2 of the present invention;

[0030] Figure 8 is the powder diffraction PXRD spectrum of CCOF-COOH in Example 2 of the present invention;

[0031] Fig. 9 This is a scanning electron microscope (SEM) image of CCOF-COOH in Example 2 of the present invention;

[0032] Fig.10 TEM image of CCOF-COOH in Example 2 of the present invention;

[0033] Fig.11 This is the thermogravimetric TGA spectrum of CCOF-COOH in Example 2 of the present invention;

[0034] Fig.12 N2 adsorption curve and pore size distribution curve of CCOF-COOH at 77 K in Example 2 of the present invention;

[0035] Fig.13 is the circular dichroism CD spectrum of CCOF-COOH in Example 2 of the present invention;

[0036] Fig.14 The PXRD spectra of CCOF-COOH in Example 3 of the present invention before and after treatment in acid, alkali and reducing media;

[0037] Fig.15 A diagram of the preparation reaction process of a novel chiral COF material with high stability constructed by a multi-component reaction provided in an embodiment of the present invention;

[0038] Fig.16 A reaction flow chart for preparing the chiral ammonia unit TAPB-Pyr provided in an embodiment of the present invention;

[0039] Fig.17 A schematic structural diagram of a covalent organic framework material provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The technical scheme in the specific embodiment of the present invention is described in detail and completely below. Obviously, the described embodiment is only a part of the specific implementation of the overall technical scheme of the present invention, rather than all implementations. Based on the overall concept of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the present invention.

[0041] On the one hand, the present invention provides a method for preparing a covalent organic framework material, comprising: using chiral ammonia unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid as raw materials, and adopting a three-component one-pot Doebner reaction to prepare a covalent organic framework material containing a quinoline-4-carboxylic acid structural unit.

[0042] The present invention provides a method for constructing a novel chiral COF material with high stability through a multi-component reaction, which adopts a three-component one-pot Doebner reaction, uses chiral aromatic amines, aromatic aldehydes and α-carbonyl acids as monomers, and simply synthesizes a chiral COF material containing a quinoline-4-carboxylic acid structural unit. The reaction process is as follows Fig.15 shown.

[0043] Multicomponent reaction is to add three or more raw materials into the reaction system, and directly obtain the final product with complex structure in a one-pot manner without separation and purification of intermediates. Multicomponent reaction embodies a high degree of atom economy and is considered to be an effective means of synthesizing molecular diversity and complexity. Among them, the Doebner reaction was discovered by German chemist Oscar Gustav Doebner. It is a three-component reaction of aromatic amines, aromatic aldehydes and α-carbonyl acids under heating and acid catalysis to produce quinoline-4-carboxylic acid. This reaction has the advantages of mild reaction conditions, high yield and easy operation, and is widely used in the field of organic synthesis. Benefiting from the huge database of organic name reactions, the Doebner reaction can be explored as a classic example of multicomponent reaction to construct COF materials. The reversible-irreversible sequence of reaction processes in the reaction provides the possibility of constructing stable covalent bonds, thereby helping to improve the chemical stability of COFs materials. The COF materials obtained based on the Doebner reaction have a high specific surface area and are rich in carboxylic acid groups. They have important application prospects in catalysis, adsorption separation and pH responsiveness. In view of the problems that imine COF materials have poor chemical stability, are not resistant to acid, alkali and reducing conditions, and have a limited scope of application, the present invention utilizes a three-component one-pot Doebner reaction to achieve the transformation from reversible linkage to irreversible linkage, thereby improving its chemical stability and broadening its scope of application. In view of the problems that chiral COF materials have low crystallinity, poor stability, and are prone to losing chiral characteristics or structural integrity during solvent thermal synthesis or in extreme chemical environments, the present invention proposes a new synthesis strategy, in which a chiral ammonia unit (TAPB-Pyr) is pre-synthesized, and a three-component Doebner reaction is performed at room temperature to obtain a new chiral COF material (CCOF-COOH) with high crystallinity and stability. This method retains the chiral characteristics while enhancing the robustness of the structure, further expanding its application potential.

[0044] In a preferred embodiment, the molar ratio of the chiral amino unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid is 1:1.5:3-6. Furthermore, the molar ratio of the chiral amino unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid is 1:1.5:3.6.

[0045] In a preferred embodiment, it specifically includes: in a reaction solvent, using chiral amino unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid as raw materials, reacting at room temperature for 3-7 days under the action of a catalyst to obtain the covalent organic framework material containing quinoline-4-carboxylic acid structural unit. Wherein, the reaction solvent is selected from any one of acetonitrile, dioxane, and DMF; the catalyst is selected from any one of p-toluenesulfonic acid, acetic acid, and aminosulfonic acid. Further, the reaction solvent is acetonitrile; the catalyst is acetic acid; reacting at room temperature for 7 days. Wherein, the volume of acetonitrile is 15 mL.

[0046] In a preferred embodiment, the process further comprises: after the reaction is completed, the crude product is centrifuged, washed in ethanol, tetrahydrofuran, and acetone in sequence, and vacuum dried to obtain the jujube-red covalent organic framework material containing quinoline-4-carboxylic acid structural units, wherein the drying temperature is 60° C. and the drying time is 24 h.

[0047] In a preferred embodiment, the chiral amine unit TAPB-Pyr is Fig.16 Prepared by the method shown.

[0048] Specifically include:

[0049] A mixture of tribromotoluene, N-bromosuccinimide, azobisisobutyronitrile and carbon tetrachloride was refluxed and stirred for 1 hour; NBS was then added to the reactant solution, and the reflux reaction was continued for 3 hours, and the solvent was removed in vacuo to obtain product A;

[0050] At 0°C, NaH was added to a dry THF solution of Boc-L-prolinol, stirred for 1 h, and then the product A was added to the mixture. After reacting for 6 h, the mixture was extracted with ethyl acetate, the organic layer was collected, dried over anhydrous sodium sulfate, and the solvent was removed in vacuo to obtain a crude product of B;

[0051] The crude product of B and 4-aminophenylboronic acid pinacol ester are dissolved in ethylene glycol dimethyl ether, and potassium carbonate aqueous solution is added under a nitrogen atmosphere, and then tetrakis(triphenylphosphine)palladium is added, and the mixture is refluxed for 48 hours. After cooling, the mixture is extracted with ethyl acetate, and the organic layer is collected and dried over anhydrous sodium sulfate. The solvent is removed in vacuo, and the mixture is purified by column chromatography to obtain product C;

[0052] The product C is dissolved in dichloromethane, trifluoroacetic acid is added at 0°C, and then stirred at room temperature for 3 h. The solvent is removed in vacuo, and water is added to clear the mixture. Then, NaHCO3 solution is added until a large amount of turbidity is generated. The mixture is extracted with ethyl acetate, the organic layer is collected, and dried over anhydrous sodium sulfate. The solvent is removed in vacuo to obtain the chiral amino unit TAPB-Pyr.

[0053] Another aspect of the present invention provides a covalent organic framework material prepared by the method for preparing a covalent organic framework material according to any of the above technical solutions, wherein the structure of the covalent organic framework material is as follows: Fig.17 shown.

[0054] The chemical stability of the covalent organic framework material (CCOF-COOH) was measured. Specifically, CCOF-COOH was immersed in different media for 24 hours, and the powder diffraction spectra before and after immersion were measured and compared; the medium was one of hydrochloric acid (6.0 M), sodium hydroxide aqueous solution (6.0 M), and sodium borohydride aqueous solution (2.0 M). The results showed that the powder diffraction spectra of the CCOF-COOH in the above media did not change at all, and it had excellent chemical stability.

[0055] In order to more clearly and in detail introduce the covalent organic framework material and the preparation method thereof provided by the embodiments of the present invention, a description will be given below in conjunction with specific embodiments.

[0056] Example 1

[0057] The preparation method of TAPB-Pyr is as follows:

[0058] 1) A mixture of tribromotoluene (1.645 g, 5 mmol), N-bromosuccinimide (NBS, 0.445 g, 2.5 mmol), azobisisobutyronitrile (AIBN) (0.08 g, 0.5 mmol) and carbon tetrachloride (45 mL) was stirred at 76° C. for 1 h, then additional NBS (0.445 g, 2.5 mmol) was added to the reactant solution and heated at 76° C. for an additional 3 h. After the solvent was removed in vacuo, product A was obtained as a light yellow solid. Figure 1 , Figure 2 A 1 H-NMR and 13 C-NMR spectrum.

[0059] 2) At 0°C, NaH (357 mg, 8.92 mmol) was added to a dry THF (15 mL) solution containing Boc-L-prolinol (1.316 g, M = 2017.27, 6.54 mmol). The mixture was stirred for 1 hour, and then A (2.8 g, M = 403.7, 6.94 mmol) was added to the mixture. After 6 hours, the mixture was quenched with NH4Cl aqueous solution and extracted with 3*100 mL of ethyl acetate. The obtained organic layer was collected and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure. The crude product of B was obtained as a yellow oily liquid.

[0060] 3) The crude product of B (2.625 g) and 4-aminophenylboronic acid pinacol ester (3.61 g, 16.5 mmol) were dissolved in 30 ml of ethylene glycol dimethyl ether. Aqueous potassium carbonate solution (10 mL, 6 M) was added under a nitrogen atmosphere. After adding tetrakis(triphenylphosphine)palladium (100 mg), refluxed for 48 h. After cooling, the mixture was extracted with 3*100 mL of ethyl acetate. The organic layer was collected and dried over anhydrous sodium sulfate. Then, the solvent was removed under reduced pressure. The residue was purified on silica gel with petroleum ether / ethyl acetate = 1:1 as the eluent to obtain C as a yellow solid. Figure 3 , Figure 4 C 1 H-NMR and 13 C-NMR spectrum.

[0061] 4) C (500 mg) was dissolved in DCM (10 ml) and the resulting solution was stirred at room temperature. TFA (5 ml) was added at 0°C, and the solution was stirred at 0°C and then at room temperature for 3 hours. The reaction mixture was concentrated under reduced pressure and water was added to clear it. NaHCO3 solution was added and adjusted until a large amount of turbidity was generated. The organic layer was collected by extraction with ethyl acetate and dried over anhydrous sodium sulfate. Then, the solvent was removed under reduced pressure to obtain TAPB-Pyr. Figure 5 , Figure 6 TAPB-Pyr 1 H-NMR and 13 C-NMR spectrum.

[0062] Example 2

[0063] The preparation method of CCOF-COOH is as follows:

[0064] TAPB-Pyr (18.57 mg, 0.04 mmol) and 2,5-dimethoxyterephthalaldehyde (12 mg, 0.06 mmol) were placed in 5 mL of acetonitrile and ultrasonicated for 1 minute to dissolve the monomers. Acetic acid solution (0.3 mL, 12 M) was added, and pyruvic acid (10 μL, 0.144 mmol) was added one day later. The reaction was allowed to stand for 7 days. The crude product was separated by centrifugation, washed with ethanol, tetrahydrofuran and acetone three times in sequence, and dried in vacuum at 60°C for 24 h to obtain a reddish-brown product CCOF-COOH. The infrared spectrum is shown in Figure 7 , PXRD spectrum see Figure 8 , SEM spectrum see Fig. 9 , TEM spectrum see Fig.10 , TGA spectrum see Fig.11 The N2 adsorption curve and pore size distribution curve at 77 K are shown in Fig.12 , circular dichroism spectrum see Fig.13 .

[0065] Example 3

[0066] The chemical stability test of CCOF-COOH is as follows:

[0067] Three portions of CCOF-COOH (5 mg) were soaked in aqueous hydrochloric acid solution (6.0 M, 5 mL), aqueous sodium hydroxide solution (6.0 M, 5 mL), and aqueous sodium borohydride solution (2.0 M, 5 mL) for 24 h, respectively. The precipitate was separated by centrifugation, washed three times with ethanol, tetrahydrofuran and acetone in sequence, and dried in vacuum at 60 °C for 24 h. Fig.14 PXRD spectra of CCOF-COOH before and after treatment in acid, alkali and reducing media.

[0068] Figure 1 is A in Example 1 of the present invention 1 In the H-NMR spectrum, the peak at 4.82 corresponds to the hydrogen of the methylene group, and the peak at 7.98 corresponds to the hydrogen of the benzene ring. 1 H NMR (400 MHz, DMSO- d 6) δ 7.98 (s, 2H), 4.82 (s, 2H);

[0069] Figure 2 is A in Example 1 of the present invention 13 In the C-NMR spectrum, the peak at 30.01 corresponds to the carbon of the methylene group, and the peaks at 123.61, 126.11, 133.83, 135.30, 135.80, and 179.84 correspond to the carbon of the benzene ring. 13 C{ 1 H} NMR (100 MHz, DMSO- d 6) δ 179.8, 135.8, 135.3, 133.8, 126.1, 123.6, 30.0;

[0070] Figure 3 is C in Example 1 of the present invention 1 In the H-NMR spectrum, the peak at 1.99 corresponds to the hydrogen of tetrahydropyrrole, the peak at 5.25 corresponds to the hydrogen of the amino group, and the peaks at 6.26-7.39 correspond to the hydrogen of the benzene ring. 1 H NMR (400 MHz, DMSO- d 6) δ7.39-7.28 (m, 8H), 6.62 (m, 6H), 5.25 (s, 6H), 3.91 (s, 2H), 3.26 (m, 4H), 1.99 (m, 5H), 1.35 (m, 9H);

[0071] Figure 4 is C in Example 1 of the present invention 13 C-NMR spectrum, the peaks at 21.58, 24.27 and 28.66 correspond to the carbon of methyl group, the peaks at 15.25, 46.33, 58.04 and 60.23 correspond to the carbon of tetrahydropyrrole, the peaks at 69.62 and 72.72 correspond to the carbon of methylene group, the peaks at 113.83-149.49 correspond to the carbon of benzene ring, and the peak at 170.82 corresponds to the carbon of ester group. 13 C{ 1 H} NMR (100 MHz, DMSO- d 6) δ 170.8, 149.5,148.4, 145.5, 141.0, 131.4, 130.5,129.1, 127.8, 125.5,114.7, 113.8, 72.7, 69.6, 60.2, 58.0, 46.3, 28.7, 24.2,21.6, 15.3;

[0072] Figure 5 is the TAPB-Pyr in Example 1 of the present invention 1 In the H-NMR spectrum, the peaks at 1.45, 1.71, 1.83, and 2.89 correspond to the hydrogen of tetrahydropyrrole and secondary amine, the peak at 5.17 corresponds to the hydrogen of amino group, and the peaks at 6.56-7.38 correspond to the hydrogen of benzene ring. 1 H NMR (400 MHz, DMSO- d 6) δ 7.38-7.24 (m, 8H), 6.56 (m, 6H), 5.17 (s, 6H), 4.02 (s, 2H), 3.26 (m, 3H), 2.89 (m, 2H), 1.83-1.45 (m, 5H);

[0073] Figure 6 is the TAPB-Pyr in Example 1 of the present invention 13 In the C-NMR spectrum, the peaks at 28.44, 47.98, 56.33 and 60.24 correspond to the carbon of tetrahydropyrrole, the peaks at 69.15 and 78.79 correspond to the carbon of methylene, and the peaks at 113.81-148.95 correspond to the carbon of benzene ring. 13 C{ 1 H} NMR (100 MHz, DMSO- d6) δ 149.0,148.4, 145.1, 140.6,131.9, 131.0, 129.2, 127.7, 125.5,115.2, 113.8, 78.8, 69.2, 60.2, 56.3, 48.0,28.4;

[0074] Figure 7 The infrared spectrum of CCOF-COOH in Example 2 of the present invention is as follows. Compared with the three monomers, CCOF-COOH does not contain TAPB-pyr at 3354 and 3455 cm -1 The characteristic peak of NH2 at 1769 cm-1 is that of CCOF-COOH, which contains carboxyl groups. -1 The characteristic peak of -C=O at 1704 cm -1 The newly appeared characteristic peak of pyridine at indicates the successful preparation of CCOF-COOH;

[0075] Figure 8 The figure is a powder diffraction PXRD spectrum of CCOF-COOH in Example 2 of the present invention, which proves that CCOF-COOH is a highly crystalline material;

[0076] Fig. 9 and 10 The SEM and TEM images of CCOF-COOH in Example 2 of the present invention are shown respectively. It can be clearly seen that CCOF-COOH is a uniform nano-spherical morphology with a particle size of about 200-300 nm;

[0077] Fig.11 The thermogravimetric TGA spectrum of CCOF-COOH in Example 2 of the present invention shows that CCOF-COOH has no obvious weight loss phenomenon below 200°C, which means that it has good thermal stability;

[0078] Fig.12 The N2 adsorption curve and pore size distribution curve of CCOF-COOH at 77 K in Example 2 of the present invention verify the permanent porosity of CCOF-COOH. The adsorption amount is 344.71 cm 3 ∙g -1 , with a specific surface area of ​​256.10 m 2 ∙g -1 , pore volume ( P / P 0 = 0.99) is 0.34 cm 3 ∙g -1 , the average pore size distribution is concentrated at about 1.3 nm;

[0079] Fig.13The CD spectrum of CCOF-COOH in Example 2 of the present invention shows a strong Cotton effect and a significant mirror image CD signal, proving that they are enantiomers of each other;

[0080] Fig.14 The PXRD spectra of CCOF-COOH in Example 3 of the present invention before and after treatment in acid, alkali and reducing media show that CCOF-COOH has excellent chemical stability and still maintains a high degree of crystallinity after being immersed in NaOH (6 M), HCl (6 M) and NaBH4 (2 M) aqueous solutions for 24 hours.

Claims

1. A method for preparing a covalent organic framework material, characterized in that: include: In a reaction solvent, a chiral ammonia unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid are used as raw materials, reacted at room temperature for 3-7 days under the action of a catalyst, and a covalent organic framework material containing a quinoline-4-carboxylic acid structural unit is prepared by a three-component one-pot Doebner reaction; the monomer molar ratio of the chiral ammonia unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid is 1:1.5:3-6; the structure of the chiral ammonia unit TAPB-Pyr is as follows: 。 2. The method for preparing a covalent organic framework material according to claim 1, characterized in that: The molar ratio of the chiral amino unit TAPB-Pyr, 2,5-dimethoxyterephthalaldehyde and pyruvic acid is 1:1.5:3.

6.

3. The method for preparing a covalent organic framework material according to claim 1, characterized in that: The reaction solvent is selected from any one of acetonitrile, dioxane and DMF; the catalyst is selected from any one of p-toluenesulfonic acid, acetic acid and aminosulfonic acid.

4. The method for preparing a covalent organic framework material according to claim 3, characterized in that: The reaction solvent is acetonitrile; the catalyst is acetic acid; and the reaction is carried out at room temperature for 7 days.

5. The method for preparing a covalent organic framework material according to claim 1, characterized in that: Also includes: After the reaction is completed, the crude product is separated by centrifugation, washed in ethanol, tetrahydrofuran and acetone in sequence, and dried in vacuum to obtain the maroon covalent organic framework material containing the quinoline-4-carboxylic acid structural unit.

6. The method for preparing a covalent organic framework material according to claim 5, characterized in that: The drying temperature is 60°C and the drying time is 24 h.

7. The method for preparing a covalent organic framework material according to claim 1, characterized in that: The chiral ammonia unit TAPB-Pyr is prepared by the following method: A mixture of tribromotoluene, N-bromosuccinimide, azobisisobutyronitrile and carbon tetrachloride was refluxed and stirred for 1 h; NBS was then added to the reactant solution, and the reflux reaction was continued for 3 h, and the solvent was removed in vacuo to obtain product A; At 0°C, NaH was added to a dry THF solution of Boc-L-prolinol, stirred for 1 h, and then the product A was added to the mixture. After reacting for 6 h, the mixture was extracted with ethyl acetate, the organic layer was collected, dried over anhydrous sodium sulfate, and the solvent was removed in vacuo to obtain a crude product of B; The crude product of B and 4-aminophenylboronic acid pinacol ester are dissolved in ethylene glycol dimethyl ether, and potassium carbonate aqueous solution is added under a nitrogen atmosphere, and then tetrakis(triphenylphosphine)palladium is added, and the mixture is refluxed for 48 hours. After cooling, the mixture is extracted with ethyl acetate, and the organic layer is collected and dried over anhydrous sodium sulfate. The solvent is removed in vacuo, and the mixture is purified by column chromatography to obtain product C; The product C is dissolved in dichloromethane, trifluoroacetic acid is added at 0°C, and then stirred at room temperature for 3 h. The solvent is removed in vacuo, and water is added to clear the mixture. Then, NaHCO3 solution is added until a large amount of turbidity is generated. The mixture is extracted with ethyl acetate, the organic layer is collected, and dried over anhydrous sodium sulfate. The solvent is removed in vacuo to obtain the chiral amino unit TAPB-Pyr.

8. The covalent organic framework material prepared according to the method for preparing a covalent organic framework material according to any one of claims 1 to 7.

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