CN110240708B

CN110240708B - Aqueous phase synthesis covalent organic framework material and preparation method thereof

Info

Publication number: CN110240708B
Application number: CN201910586894.XA
Authority: CN
Inventors: 方千荣; 王钰杰; 刘耀祖
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2019-07-02
Filing date: 2019-07-02
Publication date: 2021-03-30
Anticipated expiration: 2039-07-02
Also published as: CN110240708A

Abstract

The invention discloses a covalent organic framework material synthesized in a water phase and a preparation method thereof, belongs to the technical field of covalent organic framework materials, and discloses a simple and general method for preparing a series of high-crystalline organic porous frameworks (COFs) with the pore diameter of 1.59-2.92 nm in a water environment system through Michael addition elimination reaction. The prepared covalent organic framework material has high crystallinity, ensures a multilevel pore channel structure with ordered surface, has good universality, and can derive a plurality of covalent organic frameworks with new functional groups; the industrial production can be easily realized, the environment can not be polluted too much, and Volatile Organic Compounds (VOCs) can not be generated; moreover, a new synthesis line is developed for synthesizing COFs by Michael addition; the thermal gravimetric analysis shows that the prepared porous material has good stability; nitrogen adsorption analysis shows that the prepared COFs have higher specific surface area.

Description

Aqueous phase synthesis covalent organic framework material and preparation method thereof

Technical Field

The invention belongs to the technical field of covalent organic framework materials, and particularly relates to a covalent organic framework material synthesized in a water phase and a preparation method thereof.

Background

Covalent Organic Frameworks (COFs) are crystalline porous materials composed of light elements such as C, H, N, B, O, which are linked by covalent bonds. Due to its good pore structure, high surface area and adjustable framework composition, the COFs have a very broad variety of potential application prospects. Including gas adsorption and separation, heterogeneous catalysis, photovoltaic energy storage, and other applications. In the past decade, COFs have been obtained by some reversible chemical reactions, typically the formation of borate, imine, triazine, and imide linkages. However, almost all by-products of these chemical reactions are water; leading to the limitation of classical COFs synthesis so far to solvothermal synthesis, and its synthesis has to be carried out in sealed tubes, which require high temperatures and pressures and lead to complicated operations, high energy consumption and volatilization of Volatile Organic Compounds (VOCs). In recent years, we developed fast, normal temperature, high pressure ionothermal synthesis COFs; however, due to the high cost of ionic liquids, the application of this method to large-scale production of COFs would be greatly hindered. Therefore, it would still be very beneficial to develop a simple, low-cost, green strategy for the synthesis of COFs.

Disclosure of Invention

The invention aims to solve the technical problem of developing a simple method for constructing a microporous and mesoporous COF (chip on film) by Michael addition elimination reaction in an environmental water system. On the basis, a series of high-crystalline COFs with the aperture of 1.59-2.92 nm are successfully prepared and named as JUC-520 and JUC-521 respectively. More importantly, these COFs can be obtained in a short time (e.g., 30 minutes for JUC-521), with high yields (> 93%) and large scale production (up to 5.0 g). The invention can quickly and efficiently synthesize the high-crystal COFs material under a normal-temperature high-pressure water phase system.

The invention is realized by the following technical scheme:

an aqueous phase synthesis covalent organic framework material, the repeating structural unit of which is shown as follows:

wherein the content of the first and second substances,

the invention also aims to provide a preparation method of the covalent organic framework material by aqueous phase synthesis, which comprises the following specific steps: carrying out nucleophilic addition-elimination reaction on an intermediate 1,3, 5-tri (3-dimethylamino-1-acetyl-2-alkenyl) benzene compound and a compound B in the presence of glacial acetic acid in a pure water solvent under the air condition to generate a carbon-nitrogen single bond to obtain a covalent organic framework material, and then carrying out post-treatment steps such as drying, washing, soaking, drying again and the like; wherein the compound B is 2,4, 6-tri (4-aminophenyl) -1,3, 5-triazine or 1, 3-5-tricarboxylic acid tri (4-aminobenzamide) benzene; the molar ratio of the intermediate 1,3, 5-tri (3-dimethylamino-1-acetyl-2-alkenyl) benzene compound to the compound B is 1:1-1: 1.5.

Further, the synthesis steps of the intermediate 1,3, 5-tri (3-dimethylamino-1-acetyl-2-alkenyl) benzene are as follows: dissolving 1,3, 5-triacetylbenzene and N, N-dimethylformamide diethyl acetal in a molar ratio of 1: 3-1: 10 in a solvent, and stirring at 80-150 ℃ under dry nitrogen for 12 hours; cooling to room temperature, adding 100ml of diethyl ether to obtain a yellow crystal product, washing the product twice with n-pentane (50.0ml), and drying in vacuum; the reaction equation is as follows:

further, the solvent is one or more of toluene, N-dimethylformamide, dioxane or acetonitrile.

Further, the molar volume ratio of the 1,3, 5-triacetylbenzene in the solvent is 1mol/L to 6 mol/L.

Further, the nucleophilic addition-elimination reaction temperature is 20-120 ℃ and the time is 0.5-72 hours.

Compared with the prior art, the invention has the following advantages:

the preparation method is green, environment-friendly and simple, and is convenient to operate and implement; the prepared covalent organic framework material has high crystallinity, ensures a multilevel pore channel structure with ordered surface, has good universality, and can derive a plurality of covalent organic frameworks with new functional groups; the industrial production can be easily realized, the environment can not be polluted too much, and Volatile Organic Compounds (VOCs) can not be generated; moreover, a new synthesis line is developed for synthesizing COFs by Michael addition; the thermal gravimetric analysis shows that the prepared porous material has good stability; nitrogen adsorption analysis shows that the prepared COFs have higher specific surface area.

Drawings

FIG. 1 is an infrared spectrum of 1, 3-5-tricarboxylic acid tris (4-aminobenzamide) benzene, 1,3, 5-tris (3-dimethylamino-1-acetyl-2-enyl) benzene of the present invention and JUC-521 prepared in example 2;

wherein TCTAB represents 1, 3-5-tricarboxylic acid tris (4-aminobenzamide) benzene, TDOOB represents a compound 1,3, 5-tris (3-dimethylamino-1-acetyl-2-alkenyl) benzene, JUC-521 represents JUC-521, and stretching vibration (-3450 cm) of 1, 3-5-tricarboxylic acid tris (4-aminobenzamide) phenylamino is shown in a Fourier transform infrared (FT-IR) spectrum^-1) And 1,3, 5-tris (3-dimethylamino-1-acetyl-2-enyl) benzazepine stretching vibration (-1438 cm)^-1) Disappearance, confirming that the reaction has proceeded and is complete;

FIG. 2 is a carbon-13 solid nuclear magnetic spectrum of JUC-521 in example 2 of the present invention; wherein a nuclear magnetic peak at 145ppm confirms the formation of secondary amine bonds;

FIG. 3 is a thermogravimetric analysis of COFs in an example of the present invention; when the sample is heated to 400 ℃, 92 percent of weight is retained, and the formed COFs have high thermal stability;

FIG. 4 is an X-ray powder diffraction pattern associated with JUC-521 in the embodiment of the present invention, in which the uppermost layer is actually measured, the middle and lower layers are simulated X-ray powder diffraction patterns, the middle layer is an X-ray powder diffraction theoretical simulation pattern of an AA stacking model JUC-521, and the lower layer is an X-ray powder diffraction theoretical simulation pattern of an AB stacking model JUC-521, and the comparison of the obtained diffraction peak and the theoretical simulation pattern proves that an expected ordered pore structure is formed;

FIG. 5 is a graph showing nitrogen adsorption-desorption curves of JUC-521 according to an embodiment of the present invention, wherein BET is very good and reaches 1127m²/g；

FIG. 6 is a plot of the pore size distribution of JUC-521 in an example of the present invention, illustrating that the covalent organic framework has a uniform pore size, matched by simulations, of 1.87 nm;

FIG. 7 is an X-ray powder diffraction pattern associated with JUC-520 in the embodiment of the present invention, wherein the top layer is actually measured, the middle and lower layers are simulated X-ray powder diffraction patterns, the middle layer is an X-ray powder diffraction theoretical simulation pattern of an AA stacking model JUC-521, and the lower layer is an X-ray powder diffraction theoretical simulation pattern of an AB stacking model JUC-521; comparing the obtained diffraction peak with a theoretical simulation graph, and proving that an expected ordered pore structure is formed;

FIG. 8 is a schematic representation of the practice of the present inventionIn the example, the nitrogen adsorption-desorption curve of JUC-520 shows that the adsorption graph has good BET reaching 976m²/g；

FIG. 9 is a graph of the pore size distribution of JUC-520 in an example of the invention, illustrating that the covalent organic framework has uniform pore size, matched by simulations, at 1.53 nm.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

Example 1

Synthesis of covalent organic framework Material JUC-520

1,3, 5-tris (3-dimethylamino-1-acetyl-2-enyl) benzene (18.5mg, 0.05mmol) and 2,4, 6-tris (4-aminophenyl) -1,3, 5-triazine (17.7mg, 0.05mmol) were put into a mortar and ground for 1 minute, and then the mixture was put into a 10mL PE centrifuge tube, and glacial acetic acid (0.4mL) and water (4mL) were added. The system is placed in the air and reacts for 3 hours at normal temperature, and the generation of yellow fluffy solid can be observed. Suction filtration was carried out and the column was rinsed with 100mL of N, N-dimethylformamide and acetone, respectively. The solid obtained by final filtration was dried overnight in a vacuum oven at 80 ℃ to give the product as a yellow solid (87% yield).

The synthesis steps of the intermediate 1,3, 5-tri (3-dimethylamino-1-acetyl-2-alkenyl) benzene are as follows: 1,3, 5-triacetylbenzene (0.82g, 4.0mmol) and N, N-dimethylformamide diacetal (2.4g, 12.0mmol) were dissolved in 10.0ml of N, N-dimethylformamide and stirred at 90 ℃ under dry nitrogen for 12 hours. Cooled to room temperature, 100ml of diethyl ether are added, stirred and filtered to give the product as yellow crystals. The product was washed twice with n-pentane (50.0ml) and dried in vacuo; yield: 91%; mp 250 deg.C, anal.C₂₁H₂₇N₃O₃(369.5):Calcd C 68.27,H 7.37,N 11.37；Found C 67.92,H 7.33,N 11.06.¹H NMR(400MHz,CDCl₃)δ：2.86,3.07[2s,18H,N(CH₃)₂],5.78(d,3H,J＝12.7,COCH＝),7.75[d,3H,＝CHN(CH₃)₂],8.46(s,3H,H-2,4,6).¹³C NMR(100MHz,CDCl₃)δ:37.3,45.0[N(CH₃)₂],92.2(COCH＝),128.7(C-2,4,6),140.2(C-1,3,5),154.4[＝CHN(CH₃)₂],187.6(C＝O).

Example 2

Synthesis of covalent organic framework Material JUC-521

After 1,3, 5-tris (3-dimethylamino-1-acetyl-2-enyl) benzene (18.5mg, 0.05mmol) and 1, 3-5-tricarboxylic acid tris (4-aminobenzamide) benzene (24.0mg, 0.05mmol) were ground in a mortar for 1 minute, the mixture was put into a 10mL PE centrifuge tube, and 6mol/mL acetic acid solution (4.0mL) was added.

The system is placed in the air and reacts for 0.5 hour at normal temperature, and the generation of yellow fluffy solid can be observed. Suction filtration was carried out and the column was rinsed with 100mL of N, N-dimethylformamide and acetone, respectively. The solid obtained by final filtration was dried overnight in a vacuum oven at 80 ℃ to give the product as a yellow solid (95% yield). If the quantitative test is needed, the current equivalent is multiplied.

Claims

1. An aqueous synthetic covalent organic framework material, characterized in that its repeating structural units are as follows:

wherein the content of the first and second substances,

2. the method for preparing the covalent organic framework material for aqueous phase synthesis according to claim 1, comprising the following steps: carrying out nucleophilic addition-elimination reaction on an intermediate 1,3, 5-tri (3-dimethylamino-1-acetyl-2-alkenyl) benzene compound and a compound B in a pure water solvent in the presence of glacial acetic acid to generate a carbon-nitrogen single bond to obtain a covalent organic framework material, and then carrying out drying, washing, soaking and drying post-treatment steps to obtain the covalent organic framework material; wherein the compound B is 2,4, 6-tri (4-aminophenyl) -1,3, 5-triazine or 1,3, 5-tricarboxylic acid tri (4-aminobenzamide) benzene.

3. The method of claim 2, wherein the molar ratio of the intermediate 1,3, 5-tris (3-dimethylamino-1-acetyl-2-enyl) benzene compound to the compound B is 1:1 to 1: 1.5.

4. The method for preparing covalent organic framework material in aqueous phase synthesis according to claim 2, wherein the intermediate 1,3, 5-tris (3-dimethylamino-1-acetyl-2-enyl) benzene is synthesized by the following steps: dissolving 1,3, 5-triacetylbenzene and N, N-dimethylformamide diethyl acetal in a molar ratio of 1: 3-1: 10 in a solvent, and stirring at 80-150 ℃ under dry nitrogen for 12 hours; cooling to room temperature, adding 100ml of diethyl ether to obtain a yellow crystal product, washing the product twice with 50.0ml of n-pentane, and performing vacuum drying to obtain an intermediate; the reaction equation is as follows:

5. the method of claim 4, wherein the solvent is one or more of toluene, N-dimethylformamide, dioxane, or acetonitrile.

6. The method according to claim 4, wherein the molar volume ratio of 1,3, 5-triacetylbenzene in the solvent is 1mol/L to 6 mol/L.

7. The method of claim 2, wherein the nucleophilic addition-elimination reaction is performed at a temperature of 20 ℃ to 120 ℃ for a time of 0.5 to 72 hours.