Three-dimensional covalent organic framework material and its preparation method and application

Abstract

The present invention relates to the technical field of covalent organic framework materials, and in particular to a three-dimensional covalent organic framework material, a preparation method, and an application thereof. The three-dimensional covalent organic framework material is formed by copolymerization of a first monomer and a second monomer, wherein the general structural formula of the first monomer is as shown in Formula I or Formula II, and R 1 is selected from -NH2, -Ph-NH2 or -CHO; R1 is selected from -C, -Si, substituted or unsubstituted biphenyl, or * is a connection site; R2 to R 16 are independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy; the general structural formula of the second monomer is as shown in Formula III, R 2 Selected from ‑NH2 or ‑CHO; R 17 ~R 28 are independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy; and when R 1 When selected from ‑NH2 or ‑Ph‑NH2, R 2 Selected from ‑CHO, when R 1 When selected from ‑CHO, R 2 Selected from ‑NH2.

Description

Technical Field

[0001] The present invention relates to the technical field of covalent organic framework materials, and in particular to a three-dimensional covalent organic framework material and a preparation method and application thereof. Background Art

[0002] Covalent organic frameworks (COFs) are a new type of organic porous material composed of lightweight elements such as carbon, hydrogen, oxygen, nitrogen, boron, and silicon bound together by strong covalent bonds. Their unique elemental composition and interconnection structure theoretically give them high surface area, high porosity, low density, and strong chemical and physical stability. Therefore, these materials hold great promise for applications in optoelectronics, catalysis, sensing, energy storage, separation, and conductivity. However, current development in this field has primarily focused on two-dimensional (2D) materials, primarily due to their ease of synthesis and abundance of precursors. In contrast, the development of three-dimensional (3D) materials has been relatively slow. One major reason for this is the limited availability of symmetrical precursors suitable for the preparation of 3D materials, resulting in a limited number of reported topological structures for COFs and, indirectly, a limited variety of 3D COFs. Unlike 2D COFs, 3D COFs break the majority of π-π stacking interactions, fully exposing the conjugated system. Their unique interconnection structure also allows for the formation of abundant pores and a more complex pore environment. The above structural features make three-dimensional COFs have great application prospects in many application fields. Therefore, the development of new three-dimensional COFs precursors and the development of three-dimensional COFs with new topological structures are of great significance. Summary of the Invention

[0003] Based on this, it is necessary to provide a three-dimensional covalent organic framework material with a new topological structure and its preparation method and application.

[0004] One aspect of the present invention provides a three-dimensional covalent organic framework material X, which is formed by copolymerization of a first monomer and a second monomer.

[0005] The general structural formula of the first monomer is shown in Formula I or Formula II:

[0006]

[0007] Among them, R 1 Selected from -NH2, -Ph-NH2 or -CHO;

[0008] R1 is selected from -C, -Si, substituted or unsubstituted biphenyl, or * is the connection site;

[0009] R2~R 16Each is independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy;

[0010] The general structural formula of the second monomer is shown in Formula III:

[0011]

[0012] Among them, R 2 Selected from -NH2 or -CHO;

[0013] R 17 ~R 28 Each of the following groups is independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy;

[0014] And when R 1 When selected from -NH2 or -Ph-NH2, R 2 Selected from -CHO, when R 1 When selected from -CHO, R 2 Selected from -NH2.

[0015] In one embodiment, the general structural formula of the first monomer is as shown in Formula I-1 or Formula II-1:

[0016]

[0017] In one embodiment, the first monomer is selected from any one of the following structures:

[0018]

[0019] In one embodiment, the general structural formula of the second monomer is shown in Formula III-1:

[0020]

[0021] In one embodiment, the structural formula of the first monomer is as follows:

[0022]

[0023] The structural formula of the second monomer is as follows:

[0024]

[0025] Another aspect of the present invention provides a method for preparing the three-dimensional covalent organic framework material, comprising the following steps:

[0026] The first monomer, the second monomer, an organic solvent and a catalyst are mixed and deoxygenated, then sealed and heated for reaction to prepare a three-dimensional covalent organic framework material.

[0027] In one embodiment, the organic solvent is selected from at least one of 1,2-dichlorobenzene, 1,4-dioxane, n-butanol, ethanol, dichloromethane, N,N-dimethylformamide, chloroform, acetone, acetonitrile, tetrahydrofuran, trimethylbenzene and 1,4-dioxane.

[0028] In one embodiment, the catalyst is at least one of acetic acid, formic acid, benzenesulfonic acid and toluenesulfonic acid.

[0029] In one embodiment, the heating reaction temperature is 80° C. to 150° C., and the time is 3 to 7 days.

[0030] In another aspect, the present invention further provides the use of the three-dimensional covalent organic framework material as a gas storage material.

[0031] In one embodiment, the three-dimensional covalent organic framework material is used to store hydrogen, carbon dioxide or methane.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] The present invention utilizes a first monomer having a structure represented by Formula I or Formula II and a second monomer having a structure represented by Formula III to copolymerize to form a three-dimensional covalent organic framework material. The surface of the three-dimensional covalent organic framework material can form evenly distributed pores and has a high specific surface area. Furthermore, the three-dimensional covalent organic framework material has excellent gas storage, adsorption, storage, and release capabilities, and has potential applications, particularly in hydrogen storage, carbon dioxide storage, and methane storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is the H NMR spectrum of tetrakis(4-aminobiphenyl)methane;

[0035] Figure 2 This is the C NMR spectrum of tetrakis(4-aminobiphenyl)methane;

[0036] Figure 3 This is the H NMR spectrum of 2,3,6,7,12,13-hexa(4-formylphenyl)triptycene;

[0037] Figure 4 This is the C NMR spectrum of 2,3,6,7,12,13-hexa(4-formylphenyl)triptycene;

[0038] Figure 5The PXRD pattern of the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0039] Figure 6 This is a nitrogen adsorption-desorption isotherm curve of the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0040] Figure 7 This is a SEM scanning electron micrograph of the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0041] Figure 8 This is a hydrogen adsorption-desorption isotherm of the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0042] Figure 9 The relationship curve between the Clausius-Clapeyron equation adsorption heat and adsorption amount of hydrogen adsorbed by the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0043] Figure 10 This is a graph showing the carbon dioxide adsorption-desorption isotherm of the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0044] Figure 11 The relationship curve between the Clausius-Clapeyron equation adsorption heat and adsorption amount of carbon dioxide adsorbed by the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0045] Figure 12 This is a methane adsorption-desorption isotherm of the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1;

[0046] Figure 13 This is the relationship curve between the adsorption heat and adsorption amount of methane according to the Clausius-Clapeyron equation of the three-dimensional covalent organic framework material 3D-hea-COF prepared in Example 1. DETAILED DESCRIPTION

[0047] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] Except as shown in the operating examples or otherwise indicated, all numbers used in the specification and claims to express the amount of ingredients, physicochemical properties, etc. are understood to be adjusted by the term "about" in all cases. For example, therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the appended claims are approximate values, and those skilled in the art will be able to appropriately change these approximate values ​​using the teachings disclosed herein to seek to obtain the desired properties. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present invention, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0051] The abbreviations and symbols used herein are consistent with those commonly used by those skilled in the art of chemistry and biology. Specifically, the following abbreviations may be used in the examples and throughout the specification.

[0052] PXRD (polycrystalline X-ray diffraction)

[0053] Terms and Definitions

[0054] In the present invention, "substituted" means that a hydrogen atom in a substituted group is replaced by a substituent.

[0055] In the present invention, "substituted or unsubstituted" means that the defined group may be substituted or unsubstituted. When the defined group is substituted, it should be understood that it is optionally substituted by groups acceptable in the art, including but not limited to: nitro, halogen atoms, C 1-10 Alkyl, C 1-10 alkoxy, or a combination of the above groups, etc.

[0056] In the present invention, "alkyl" refers to a saturated hydrocarbon group, which is a hydrocarbon group formed by removing one hydrogen from an alkane molecule. The number of carbon atoms in an alkyl group can be 1 to 10, 1 to 8, 1 to 6, or 1 to 4. Phrases containing this term, such as "C 1-9 "Alkyl" refers to an alkyl group containing 1 to 9 carbon atoms, each occurrence of which can be independently C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl or C9 alkyl.

[0057] The term "alkoxy" refers to a group having an -O-alkyl group, i.e., an alkyl group as defined above connected to a parent core structure via an oxygen atom. Phrases containing this term, for example, "C1-C6 alkoxy" means that the alkyl portion contains 1 to 6 carbon atoms, and each occurrence can be independently C1 alkoxy, C2 alkoxy, C3 alkoxy, C4 alkoxy, C5 alkoxy or C6 alkoxy. Suitable examples include, but are not limited to, methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt) and tert-butoxy (-OC(CH3)3 or -OtBu).

[0058] An embodiment of the present invention provides a three-dimensional covalent organic framework material formed by copolymerization of a first monomer and a second monomer.

[0059] The general structural formula of the first monomer is shown in Formula I or Formula II:

[0060]

[0061] Among them, R 1 Selected from -NH2, -Ph-NH2 or -CHO;

[0062] R1 is selected from -C, -Si, substituted or unsubstituted biphenyl, or * is the connection site;

[0063] R2~R 16 Each is independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy;

[0064] The general structural formula of the second monomer is shown in Formula III:

[0065]

[0066] Among them, R 2 Selected from -NH2 or -CHO;

[0067] R 17 ~R 28Each of the following groups is independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy;

[0068] And when R 1 When selected from -NH2 or -Ph-NH2, R 2 Selected from -CHO, when R 1 When selected from -CHO, R 2 Selected from -NH2.

[0069] In the "-Ph-NH2", "Ph" is a benzene ring, and -NH2 can replace hydrogen at any position on the benzene ring. Suitable structural formulas of "-Ph-NH2" include any one of the following structures:

[0070]

[0071] Wherein, * is a connection site, and R2 to R5 are the same as defined above and will not be repeated here.

[0072] In some preferred embodiments, the structural formula of "-Ph-NH2" is * is the connection site.

[0073] In some embodiments, the general structural formula of the first monomer is as shown in Formula I-1 or Formula II-1:

[0074]

[0075] Among them, R 1 、R2~R 16 The definition is the same as above and will not be repeated here.

[0076] In some embodiments, the first monomer is selected from any one of the following structures:

[0077]

[0078] Among them, R 1 The definition is the same as above and will not be repeated here.

[0079] In some embodiments, the general structural formula of the second monomer is as shown in Formula III-1:

[0080]

[0081] Among them, R 2 The definition is the same as above and will not be repeated here.

[0082] In some embodiments, the structural formula of the first monomer is as follows:

[0083]

[0084] Among them, R 1 The structural formula of the second monomer is as follows:

[0085]

[0086] Among them, R 2 The definition is the same as above and will not be repeated here.

[0087] In another aspect, the present invention provides a method for preparing the three-dimensional covalent organic framework material described above, which comprises the following steps:

[0088] A mixture of the first monomer, the second monomer, an organic solvent and a catalyst is heated and reacted in a non-oxidizing atmosphere to prepare a three-dimensional covalent organic framework material.

[0089] To create a non-oxidizing atmosphere, the reaction system must first be deoxygenated. This deoxygenation can be achieved through a freeze-thaw method, which involves freezing the sealed reaction system with liquid nitrogen, evacuating the system after complete freezing, and then allowing it to return to room temperature. This freeze-thaw process can be repeated to completely remove oxygen from the reactants.

[0090] The heating reaction temperature is 80° C. to 150° C., and the time is 3 to 7 days. Preferably, the heating reaction temperature is 120° C., and the time is 5 days.

[0091] In some embodiments, before mixing the first monomer, the second monomer, the organic solvent, and the catalyst, the mixed first monomer and the second monomer may be deoxygenated. The deoxygenation treatment is performed by discharging and charging a non-oxygen gas to perform gas replacement. The number of times the gas is charged and discharged is not limited, as long as the oxygen in the reactants can be removed. The non-oxygen gas may be one or both of nitrogen and helium.

[0092] In some embodiments, the first organic solvent can be selected from alcohols, ethers, aromatic hydrocarbons, amides, sulfoxides, amides, and derivatives thereof. Specific examples include, but are not limited to, 1,2-dichlorobenzene, 1,4-dioxane, n-butanol, ethanol, dichloromethane, N,N-dimethylformamide, chloroform, acetone, acetonitrile, tetrahydrofuran, trimethylbenzene, and combinations thereof. In some preferred embodiments, the first organic solvent is selected from a combination of trimethylbenzene and 1,4-dioxane.

[0093] In some embodiments, the catalyst is a catalyst commonly used in the preparation of covalent organic framework materials known in the art and can be selected from carboxylic acids or sulfonic acids. Examples thereof include acetic acid, formic acid, benzenesulfonic acid, or toluenesulfonic acid. The molar ratio of the catalyst to the first organic solvent can be 1:5 to 1:30. Preferably, the molar ratio of the catalyst to the first organic solvent is 1:10.

[0094] In some embodiments, the preparation method further comprises the steps of washing, purifying and drying the product after the reaction.

[0095] The specific step of washing is: soaking the obtained product in a second organic solvent, wherein the second organic solvent can be selected from one or more of tetrahydrofuran, ethanol or acetone.

[0096] In the most preferred embodiment, the obtained product is immersed in the second organic solvent for 12 hours, wherein the second organic solvent is replaced with fresh solvent every 3 hours.

[0097] Preferably, the first organic solvent and the second organic solvent are both selected from ultra-dry solvents to ensure that the solvents have high purity and low water content.

[0098] The purification method is Soxhlet extraction, and the extraction solvent can be acetone or tetrahydrofuran. The extraction time is 20 hours to 30 hours. Preferably, the extraction solvent is acetone, and the extraction time is 24 hours.

[0099] The drying condition is vacuum drying at a drying temperature of 25°C to 140°C, preferably, the drying temperature is 80°C.

[0100] The present invention further provides the use of the three-dimensional covalent organic framework material as a gas storage material.

[0101] In some embodiments, the three-dimensional covalent organic framework material can be used to store hydrogen, carbon dioxide, or methane.

[0102] The following are specific examples. They are intended to further illustrate the present invention and help those skilled in the art and researchers further understand the present invention. The relevant technical conditions, etc., do not constitute any limitation to the present invention. Any modifications made within the scope of the claims of the present invention are within the scope of protection of the claims of the present invention.

[0103] Example 1

[0104] (1) Synthesis of tetrakis(4-aminobiphenyl)methane (TABPM), the synthetic route is as follows:

[0105]

[0106] Tetrakis(4-bromophenyl)methane (0.32 g, 0.50 mol) and 4-aminophenylboronic acid pinacol ester (0.44 g, 2.0 mol) were added to 14 mL of a 1:1 mixture of tetrahydrofuran and toluene. Sodium hydroxide (0.30 g, 7.5 mmol) was then added, followed by bis(triphenylphosphine)palladium(II) dichloride [PdCl2(PPh3)2] (0.18 g, 0.25 mmol). The mixture was degassed three times with nitrogen and refluxed at 100°C under nitrogen for 36 hours. The tetrahydrofuran and toluene were removed, and methanol was added. After filtration, the filtrate was dried under high vacuum for 10 hours to yield 0.14 g, a 41% yield.

[0107] Structural characterization: NMR hydrogen spectrum and NMR carbon spectrum were used to characterize tetrakis(4-aminobiphenyl)methane. The NMR hydrogen spectrum of tetrakis(4-aminobiphenyl)methane is as follows Figure 1 As shown, the NMR carbon spectrum of tetrakis(4-aminobiphenyl)methane is as follows Figure 2 shown.

[0108] (2) Synthesis of 2,3,6,7,12,13-hexa(4-formylphenyl)triptycene (HFPTP). The synthetic route is as follows:

[0109]

[0110] Cesium carbonate (60.40 g, 185.38 mmol) and bis(triphenylphosphine)dichloropalladium(II) (1.40 g, 2.00 mmol) were added to a 200 ml tetrahydrofuran solution of 2,3,6,7,12,13-hexabromotriptycene (15.00 g, 20.61 mmol) and 4-formylphenylboronic acid (27.80 g, 185.41 mmol). The mixture was stirred and refluxed under a nitrogen atmosphere for 48 hours. The mixture was then cooled to room temperature and the solvent removed by filtration under reduced pressure. 500 ml of distilled water was added to the filter residue. The mixture was extracted with dichloromethane, and the organic layer was dried over Na2SO4 and concentrated. The crude product was purified by chromatography using dichloromethane and ethyl acetate as eluents. 8.8 g of pure HFPTP (white solid) was obtained in a 48.6% yield.

[0111] Structural characterization: H NMR and C NMR were used to characterize 2,3,6,7,12,13-hexa(4-formylphenyl)triptycene. The H NMR spectrum of 2,3,6,7,12,13-hexa(4-formylphenyl)triptycene is shown in Figure 3 As shown, the C NMR spectrum of 2,3,6,7,12,13-hexa(4-formylphenyl)triptycene is as follows Figure 4 shown.

[0112] (3) Synthesis of 3D-hea-COF. The synthetic route is as follows:

[0113]

[0114] In the high-boron pressure-resistant glass tube (specification: length × diameter = 10 × 8mm 2 ) were added to a glass tube containing 2,3,6,7,14,15-hexa(4-formylphenyl)triptycene (HFPPT, 44.0 mg, 0.05 mmol) and tetra(4-aminophenyl)methane (TABPM, 51.3 mg, 0.075 mmol), and the tube was sealed with a rubber stopper. The tube was then repeatedly evacuated and filled with nitrogen to remove oxygen from the reactants. Ultra-dry trimethylbenzene (1.0 ml), 1,4-dioxane (1.0 ml), and 6.0 M acetic acid (0.2 ml) were then added in sequence, and the mixture was allowed to stand at room temperature for 30 min. Next, the reaction system at the lower end of the tube was completely immersed in liquid nitrogen at 77 K. The liquid portion was completely frozen, then thawed under vacuum and allowed to return to room temperature. This freeze-thaw cycle was repeated three times. The solvent at the lower end of the tube was re-frozen with liquid nitrogen and evacuated to an internal pressure of 0.15 mm Hg. The tube was then sealed with a handheld flame gun. After the solvent was completely dissolved and returned to room temperature, the glass tube was placed in a forced-air oven at 120°C for 5 days to produce a dark red precipitate, which was isolated by filtration through a medium glass filter and washed with anhydrous acetone (40.0 mL). The product was soaked in anhydrous acetone (40.0 mL) for 12 hours, during which time the original solvent was decanted and replenished four times. After vacuum removal of the solvent at 80°C, a light yellow crystalline solid, 3D-hea-COF, was obtained.

[0115] Structural characterization and morphology testing:

[0116] 1. PXRD test

[0117] The 3D-hea-COF prepared in Example 1 was placed in a vacuum oven at 80 degrees Celsius for 8 hours to remove the residual reagents in the pores. The PXRD data of the sample was measured using a Bruker D8 ADVANCE X-ray diffractometer in the range of 2° to 40° at a scanning speed of 0.02° / s. The results are as follows: Figure 5 As shown. Figure 5 It can be seen that 3D-hea-COF has a high degree of crystallinity, and the experimental data and the simulation values ​​are in good agreement, indicating that the light yellow crystalline solid prepared above has the structural formula shown in 3D-hea-COF.

[0118] 2. Nitrogen adsorption-desorption test

[0119] The 3D-hea-COF prepared in Example 1 was degassed at 120°C for 12 hours, and then its nitrogen adsorption-desorption isotherm data were measured at 77K using a BEL MAXⅡ fully automatic surface area analyzer. The results are as follows: Figure 6 As shown. The calculated specific surface area of ​​3D-hea-COF is 1804.0 g / m 2 , the maximum pore size is concentrated at 1.6nm.

[0120] 3. SEM scanning electron microscope

[0121] The morphology of the 3D-hea-COF prepared in Example 1 was tested by SEM scanning electron microscopy. Figure 7 As shown, Figure 7 It shows that the appearance of 3D-hea-COF is relatively uniform particles, and the particle size distribution is around 1 micron.

[0122] Gas adsorption performance test

[0123] 1. Hydrogen adsorption test

[0124] The 3D-hea-COF prepared in Example 1 was degassed at 120°C for 12 hours, and then its hydrogen adsorption-desorption isotherm data were measured at 77K and 87K using a BEL MAXⅡ fully automatic surface area analyzer. The results are as follows: Figure 8 As shown. According to calculations, the hydrogen adsorption capacity of 3D-hea-COF at 77K and 1 atmosphere pressure is 193.48 cm 3 g -1 (1.70 wt%), the hydrogen adsorption capacity of 3D-hea-COF at 87 K and 1 atm was 131.03 cm 3 g -1 (1.16 wt%). Based on the Clausius-Clapeyron equation, the adsorption heat of hydrogen on 3D-hea-COF was calculated using adsorption data at 77 K and 87 K, which was 8.09 KJ / mol. The relationship between the Clausius-Clapeyron equation adsorption heat of hydrogen on 3D-hea-COF and the adsorption amount is shown in the figure below. Figure 9 shown.

[0125] 2. Carbon dioxide adsorption test

[0126] The 3D-hea-COF prepared in Example 1 was degassed at 120°C for 12 hours, and then its carbon dioxide adsorption-desorption isotherm data were measured at 273K and 298K using a BEL MAXⅡ fully automatic surface area analyzer. The results are as follows: Figure 10 As shown. According to calculations, the carbon dioxide adsorption capacity of 3D-hea-COF at 273K and 1 atmosphere pressure is 80.01cm 3 g -1(15.7 wt%), the carbon dioxide adsorption capacity of 3D-hea-COF at 298 K and 1 atm was 42.26 cm 3 g -1 (8.01 wt%). Based on the Clausius-Clapeyron equation, the heat of adsorption of carbon dioxide on 3D-hea-COF was calculated using adsorption data at 273K and 298K, which was 27.62 kJ / mol. The relationship between the Clausius-Clapeyron equation heat of adsorption of carbon dioxide on 3D-hea-COF and the adsorption amount is shown in the figure below. Figure 11 shown.

[0127] 3. Methane adsorption test

[0128] The 3D-hea-COF prepared in Example 1 was degassed at 120°C for 12 hours, and then its methane adsorption-desorption isotherm data were measured at 273K and 298K using a BEL MAXⅡ fully automatic surface area analyzer. The results are as follows: Figure 12 As shown. According to calculations, the methane adsorption capacity of 3D-hea-COF at 273K and 1 atmosphere pressure is 21.77 cm 3 g -1 (1.53 wt%), the methane adsorption capacity of 3D-hea-COF at 298 K and 1 atm was 10.74 cm 3 g -1 (0.76 wt%). Based on the Clausius-Clapeyron equation, the heat of methane adsorption on 3D-hea-COF was calculated using adsorption data at 273 K and 298 K, which was 24.45 KJ / mol. The relationship between the Clausius-Clapeyron equation heat of methane adsorption on 3D-hea-COF and the adsorption amount is shown in the figure below. Figure 13 shown.

[0129] Example 2

[0130] The preparation method of this embodiment is basically the same as that of Example 1, except that different monomers are used. The specific synthesis steps are as follows:

[0131] In the high-boron pressure-resistant glass tube (specification: length × diameter = 10 × 8mm 2) was added to a glass tube containing 2,3,6,7,14,15-hexa(4-aminophenyl)triptycene (44 mg, 0.05 mmol) and tetra(4-aminophenyl)methane (28.5 mg, 0.075 mol), and the tube was sealed with a rubber stopper. The tube was then repeatedly evacuated and filled with nitrogen to remove oxygen from the reactants. Ultra-dry trimethylbenzene (1.0 ml), 1,4-dioxane (1.0 ml), and 6.0 M acetic acid (0.2 ml) were then added in sequence, and the mixture was allowed to stand at room temperature for 30 min. Next, the reaction system at the lower end of the tube was completely immersed in liquid nitrogen at 77 K. The liquid portion was completely frozen, then thawed under vacuum and allowed to return to room temperature. This freeze-thaw cycle was repeated three times. The solvent at the lower end of the tube was re-frozen with liquid nitrogen and evacuated to an internal pressure of 0.15 mm Hg. The tube was then sealed with a handheld flame gun. After the solvent was completely dissolved and returned to room temperature, the glass tube was placed in a forced air oven at 120°C for 5 days to produce a dark red precipitate, which was separated by filtration through a medium glass filter and washed with anhydrous acetone (40.0 mL). The product was soaked in anhydrous acetone (40.0 mL) for 12 hours, during which time the original solvent was poured out and fresh solvent was added four times. The solvent was removed by vacuum at 80°C to obtain the product.

[0132] Example 3

[0133] The preparation method of this embodiment is basically the same as that of embodiment 1, except that different monomers are used. The specific synthesis steps are as follows:

[0134] In the high-boron pressure-resistant glass tube (specification: length × diameter = 10 × 8mm 2) were added to a glass tube containing 2,3,6,7,14,15-hexa(4-aminophenyl)triptycene (40.0 mg, 0.05 mmol) and 1,3,5,7-tetra(4-benzaldehyde)-adamantane (41.4 mg, 0.075 mmol), and the tube was sealed with a rubber stopper. The tube was then repeatedly evacuated and filled with nitrogen to remove oxygen from the reactants. Ultra-dry trimethylbenzene (2.0 ml), 1,4-dioxane (2.0 ml), and 6.0 M acetic acid (0.2 ml) were then added in sequence, and the mixture was allowed to stand at room temperature for 30 min. Next, the reaction system at the lower end of the tube was completely immersed in liquid nitrogen at 77 K. The liquid portion was completely frozen, then thawed under vacuum and allowed to return to room temperature. This freeze-thaw cycle was repeated three times. The solvent at the lower end of the tube was re-frozen with liquid nitrogen and evacuated to an internal pressure of 0.15 mm Hg. The tube was then sealed with a handheld flame gun. After the solvent was completely dissolved and returned to room temperature, the glass tube was placed in a forced air oven at 120°C for 5 days to produce a dark red precipitate, which was separated by filtration through a medium glass filter and washed with anhydrous acetone (40.0 mL). The product was soaked in anhydrous acetone (40.0 mL) for 12 hours, during which time the original solvent was poured out and fresh solvent was added four times. The solvent was removed by vacuum at 80°C to obtain the product.

[0135] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The embodiments described above only express several implementation methods of the present invention, which are convenient for understanding the technical solutions of the present invention in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all fall within the scope of protection of the present invention. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the scope of protection of the claims attached to the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A three-dimensional covalent organic framework material, characterized in that: It is formed by copolymerization of a first monomer and a second monomer, The general structural formula of the first monomer is shown in Formula I or Formula II: Among them, R 1 Selected from -NH2, -Ph-NH2 or -CHO; R1 is selected from -C, -Si, substituted or unsubstituted biphenyl, or * is the connection site; R2~R 16 R is independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy; 17 Selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy; The general structural formula of the second monomer is shown in Formula III: Among them, R 2 Selected from -NH2 or -CHO; R 17 ~R 28 Each of the following groups is independently selected from -H, -Cl, -Br, -F, -I, C1-C6 straight-chain alkyl, C1-C6 branched-chain alkyl, or C1-C6 alkoxy; And when R 1 When selected from -NH2 or -Ph-NH2, R 2 Selected from -CHO, when R 1 When selected from -CHO, R 2 Selected from -NH2.

2. The three-dimensional covalent organic framework material according to claim 1, characterized in that The general structural formula of the first monomer is shown in Formula I-1 or Formula II-1:

3. The three-dimensional covalent organic framework material according to claim 1, characterized in that The first monomer is selected from any one of the following structures:

4. The three-dimensional covalent organic framework material according to claim 1, characterized in that The general structural formula of the second monomer is shown in Formula III-1:

5. The three-dimensional covalent organic framework material according to claim 1, characterized in that The structural formula of the first monomer is as follows: The structural formula of the second monomer is as follows:

6. The method for preparing a three-dimensional covalent organic framework material according to any one of claims 1 to 5, characterized in that: The following steps are involved: A mixture of the first monomer, the second monomer, an organic solvent and a catalyst is heated and reacted in a non-oxidizing atmosphere to prepare a three-dimensional covalent organic framework material.

7. The method for preparing a three-dimensional covalent organic framework material according to claim 6, characterized in that: The organic solvent is selected from at least one of 1,2-dichlorobenzene, 1,4-dioxane, n-butanol, ethanol, dichloromethane, N,N-dimethylformamide, chloroform, acetone, acetonitrile, tetrahydrofuran and trimethylbenzene.

8. The method for preparing a three-dimensional covalent organic framework material according to claim 6, wherein: The catalyst is at least one of acetic acid, formic acid, benzenesulfonic acid and toluenesulfonic acid.

9. The method for preparing a three-dimensional covalent organic framework material according to claim 6, characterized in that: The temperature of the heating reaction is 80° C. to 150° C., and the time is 3 to 7 days.

10. Use of the three-dimensional covalent organic framework material according to any one of claims 1 to 5 as a gas storage material.

11. The use according to claim 10, characterized in that The three-dimensional covalent organic framework material is used for storing hydrogen, carbon dioxide or methane.

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