Dispersible covalent triazine skeleton as well as preparation method and application thereof

Abstract

The invention relates to the technical field of covalent triazine frameworks, in particular to a dispersible covalent triazine framework and a preparation method and application thereof. The preparation method comprises steps as follows: nitrile monomers are provided and comprise a phthalonitrile monomer with a para-symmetric structure and a phthalonitrile monomer with a para-asymmetric structure, and the phthalonitrile monomer with the para-asymmetric structure accounts for 0.001%-100% of the nitrile monomer in percentage by mass; mixing the nitrile monomer, a catalyst and a solvent to obtain a reaction solution; and carrying out a reaction on the reaction liquid to obtain the dispersible covalent triazine skeleton. Under the conditions of a certain temperature, a catalyst and a solvent, a phthalonitrile monomer with a para-symmetric structure and a phthalonitrile monomer with a para-asymmetric structure can be prepared into partially crystallized CTF through a one-pot method, and the CTF can be dispersed in solvents such as N, N-dimethylformamide and the like, so that the CTF can be dispersed in the solvents such as N, N-dimethylformamide and the like. The method is used for preparing organic gel, aerogel and catalysis.

Description

Technical Field

[0001] The invention relates to the technical field of covalent triazine skeletons, and in particular to a dispersible covalent triazine skeleton and a preparation method and application thereof. Background Art

[0002] Covalent triazine framework (CTF) is a kind of covalent organic framework (COFs) material with graphite π-conjugated structure connected by nitrogen-containing fused rings, which has the advantages of high thermal and chemical stability. They have been widely used in catalysis, energy storage, dye adsorption and gas adsorption. Most CTFs exist and are used in the form of insoluble particles or powders, which is far from meeting the requirements for various applications. Due to the strong van der Waals attraction and highly spatially confined stacking characteristics, it is very challenging to exfoliate bulk CTFs similar to graphite structures. To solve this problem, researchers have been committed to finding simple and effective methods. Sun et al. reported a high-energy ball milling strategy for the superacid synthesis of bulk CTFs, which produced abundant few-layer nanosheets. Huang et al. used ultrasound-assisted exfoliation to solvothermally synthesize CTF powders and separated a small amount of nanolayers into the supernatant. Zhu et al. used piranha solution as an intercalation agent for the exfoliation of ionothermally synthesized CTFs. Despite these efforts, the exfoliation method has achieved limited success. Another approach is to directly design and synthesize 2D CTFs. Liu et al. precisely achieved polymerization at the interface of two liquids to prepare trace amounts of CTF nanosheets. Wang et al. performed polycondensation on the surface of nano-silica and obtained spherical nano-CTFs after removing the template. Although bottom-up growth methods have opened up new possibilities for novel CTFs, they usually require precise control of the reaction to avoid unwanted aggregation or precipitation. Therefore, the development of simple and cost-effective synthetic methods to obtain nano- or peelable CTFs remains a daunting challenge. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a dispersible covalent triazine skeleton and a preparation method and application thereof, aiming to solve the problem that the existing methods cannot effectively prepare nano or strippable CTF.

[0004] The technical solution of the present invention is as follows:

[0005] The first aspect of the present invention provides a method for preparing a dispersible covalent triazine skeleton, which comprises the steps of:

[0006] Providing nitrile monomers, the nitrile monomers comprising phthalonitrile monomers having a para-symmetrical structure and phthalonitrile monomers having a para-asymmetric structure, wherein the mass percentage of the phthalonitrile monomers having a para-asymmetric structure is 0.001% to 100% of the nitrile monomers;

[0007] mixing the nitrile monomer, a catalyst and a solvent to obtain a reaction solution;

[0008] The reaction solution is reacted to obtain the dispersible covalent triazine skeleton.

[0009] Optionally, the phthalonitrile monomer having a para-symmetrical structure includes one or more of terephthalonitrile, tetrachloroterephthalonitrile, tetrafluoroterephthalonitrile, and 4,4'-biphenylcarbonitrile.

[0010] Optionally, the phthalonitrile monomer having a para-asymmetric structure includes one or more of methyl terephthalonitrile, 2-ethynyl terephthalonitrile, ethyl terephthalonitrile, hydroxy terephthalonitrile, isophthalonitrile, phthalonitrile, 4-propoxy phthalonitrile, tetrafluorophthalonitrile, 3,6-dihydroxyphthalonitrile, 4,5-dichlorophthalonitrile, diethyl phthalonitrile, 4-p-aminophenoxyphthalonitrile, 4-(2',6'-dimethylphenoxy)phthalonitrile, 3-nitrophthalonitrile, 4-hexyloxyphthalonitrile, 3-chlorophthalonitrile, 4,5-dichlorophthalonitrile, tetrachlorophthalonitrile, tetrafluorophthalonitrile, 5-chloro-2,4,6-trifluoroisophthalonitrile, and 4-n-dodecyloxyphthalonitrile.

[0011] Optionally, the catalyst includes one or more of trifluoromethanesulfonic acid, magic acid, fluorosulfonic acid, fluoroantimonic acid, carborane acid, and piranha solution.

[0012] Optionally, the solvent includes one or more of ethanol, dichloromethane, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, ethyl acetate, ether, ethyl bromide, tetrahydrofuran, pyridine, acetone, propanol, dioxane, methyl ethyl ketone, n-butanol, carbon tetrachloride, carbon disulfide, cyclohexane, hexane, triethylamine, petroleum ether, benzene, toluene, xylene, 2-pyrrolidone, N-methyl-2-pyrrolidone, methyl tert-butyl ether, ethylene glycol dimethyl ether, and kerosene.

[0013] Optionally, the mass ratio of the nitrile monomer, the catalyst and the solvent is 1:(0.01-1000):(0.01-1000).

[0014] Optionally, the reaction temperature is a temperature between -10 and 100°C.

[0015] Optionally, the reaction time is 5 min-120 h.

[0016] The second aspect of the present invention provides a dispersible covalent triazine skeleton, wherein the dispersible covalent triazine skeleton is prepared by the preparation method of the dispersible covalent triazine skeleton described in the present invention.

[0017] The third aspect of the present invention provides a use of the dispersible covalent triazine skeleton of the present invention in the preparation of an organogel or an aerogel.

[0018] The fourth aspect of the present invention provides a use of the dispersible covalent triazine skeleton of the present invention as a catalyst.

[0019] Beneficial effects: Compared with the existing ball milling, ultrasound and piranha solution methods, the present invention proposes a simple, economical and efficient method, that is, through the introduction of phthalonitrile monomers with a para-asymmetric structure, such as methyl terephthalonitrile, a partial amorphous region is formed, thereby preparing a CTF material that can be directly dispersed by an organic solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the preparation and application example of the solvent-stripped CTF in the present invention.

[0021] Figure 2 This is a process diagram of the polymerization of terephthalonitrile with a para-symmetric structure to form a triazine structure through Gaussian DFT calculation simulation in Example 1.

[0022] Figure 3 The XRD diagrams of the products obtained from the reactions with different MTPN monomer contents in Examples 2-4.

[0023] Figure 4 This is a diagram showing the dispersion of the product obtained in Example 1-4 in DMF solvent.

[0024] Figure 5 Figures a and b are the rheological property test results and gelation process observations of MTPN75% dispersed in DMF in the initial state (0h) and after standing for 12h (illustration in a), c is the aerogel prepared after MCNT was modified by MTPN75%, and d is the SEM image of the aerogel. DETAILED DESCRIPTION

[0025] The present invention provides a dispersible covalent triazine skeleton and a preparation method and application thereof. To make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] The embodiment of the present invention provides a method for preparing a dispersible covalent triazine skeleton, which comprises the steps of:

[0027] Providing nitrile monomers, the nitrile monomers comprising phthalonitrile monomers having a para-symmetrical structure and phthalonitrile monomers having a para-asymmetric structure, wherein the mass percentage of the phthalonitrile monomers having a para-asymmetric structure is 0.001% to 100% of the nitrile monomers;

[0028] mixing the nitrile monomer, a catalyst and a solvent to obtain a reaction solution;

[0029] The reaction solution is reacted to obtain the dispersible covalent triazine skeleton.

[0030] In the embodiment of the present invention, nitrile monomers with functional groups having different dipole moments (i.e., different ratios of phthalonitrile monomers with para-symmetric structures and phthalonitrile monomers with para-asymmetric structures) are selected as in-plane building units to weaken the layered interactions, thereby promoting the smooth peeling of highly conjugated layered CTF materials with strong connections under competitive interactions. By introducing non-crystalline regions and random stacking in the CTF layer, the capillary force and surface energy of the solvent can promote the stacking of CTF layers, thereby promoting effective peeling and achieving the dispersion of CTF in the solvent.

[0031] At a certain temperature (such as room temperature), phthalonitrile monomers with para-asymmetric structures, such as nitrile monomers containing functional groups such as methyl, are introduced into the simple solvent synthesis process of CTF. Functional groups such as methyl are bound to the layered skeleton, so that CTF can be effectively peeled into asymmetric layers, and the CTF forms supramolecular nanocolloids in solvents such as N,N-dimethylformamide. It is worth noting that these dispersible CTFs can form organic gels after standing in solvents. In addition, CTF organic gels containing carbon nanotubes (CNTs) are freeze-dried to form aerogels. In the presence of CNTs, the gelation ability of CTF is enhanced. In addition, CTF dispersions can accelerate the synthesis and degradation of substances such as dyes, and have great prospects in the field of catalysis.

[0032] In one embodiment, the mass percentage of the phthalonitrile monomers having a para-asymmetric structure to the nitrile monomers is 10% to 90%, and the CTF prepared in this way has better dispersibility in the solvent.

[0033] In one embodiment, the phthalonitrile monomer having a para-symmetric structure includes one or more of terephthalonitrile (TPN), tetrachloroterephthalonitrile, tetrafluoroterephthalonitrile, 4,4'-biphenylcarbonitrile, etc. Preferably, terephthalonitrile is used.

[0034] In one embodiment, the phthalonitrile monomers having a para-asymmetric structure include one or more of methyl terephthalonitrile (MTPN), 2-ethynyl terephthalonitrile, ethyl terephthalonitrile, hydroxy terephthalonitrile, isophthalonitrile, phthalonitrile, 4-propoxy phthalonitrile, tetrafluoro phthalonitrile, 3,6-dihydroxy phthalonitrile, 4,5-dichloro phthalonitrile, diethyl phthalonitrile, 4-p-aminophenoxy phthalonitrile, 4-(2',6'-dimethylphenoxy) phthalonitrile, 3-nitro phthalonitrile, 4-hexyloxy phthalonitrile, 3-chloro phthalonitrile, 4,5-dichloro phthalonitrile, tetrachloro phthalonitrile, tetrafluoro phthalonitrile, 5-chloro-2,4,6-trifluoroisophthalonitrile, 4-n-dodecyloxy phthalonitrile, etc. Methyl terephthalonitrile is preferred.

[0035] In one embodiment, the catalyst includes one or more of trifluoromethanesulfonic acid (TfOH), magic acid, fluorosulfonic acid, fluoroantimonic acid, carborane acid, piranha solution, etc. Trifluoromethanesulfonic acid is preferred.

[0036] In one embodiment, the solvent includes one or more of ethanol, dichloromethane (DCM), chloroform, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile, ethyl acetate, ether, ethyl bromide, tetrahydrofuran, pyridine, acetone, propanol, dioxane, methyl ethyl ketone, n-butanol, carbon tetrachloride, carbon disulfide, cyclohexane, hexane, triethylamine, petroleum ether, benzene, toluene, xylene, 2-pyrrolidone, N-methyl-2-pyrrolidone, methyl tert-butyl ether, ethylene glycol dimethyl ether, kerosene, etc.

[0037] In one embodiment, the mass ratio of the nitrile monomer, the catalyst, and the solvent is 1:

[0038] (0.01~1000):(0.01~1000).

[0039] Preferably, the mass ratio of the nitrile monomer, the catalyst, and the solvent is 1:(1-10):(10-100), which facilitates separation and subsequent drying after the reaction to obtain CTF.

[0040] In one embodiment, the reaction temperature is a temperature between -10 and 100°C, such as -10°C, 0°C, 10°C, 25°C, 45°C, 55°C, 70°C, 85°C, 100°C, etc. Preferably, the room temperature is 25°C.

[0041] In one embodiment, the reaction time is 5 min-120 h, such as 5 min, 30 min, 1 h, 10 h, 20 h, 24 h, 40 h, 50 h, 60 h, 80 h, 100 h, 120 h, etc.

[0042] In one embodiment, the reaction is carried out with stirring.

[0043] In one embodiment, the step of reacting the reaction solution to obtain the dispersible covalent triazine skeleton specifically includes:

[0044] The reaction solution is placed in a shaker with a shaking rate of 10 rpm-10000 rpm (such as 10 rpm, 50 rpm, 100 rpm, 500 rpm, 1000 rpm, 5000 rpm, 10000 rpm, etc.), reacted at -10 to 100° C. (such as -10° C., 0° C., 10° C., 30° C., 50° C., 80° C., 100° C., etc.) for 5 min-120 h, centrifuged to allow the product to precipitate at the bottom, removed the supernatant, and vacuum dried to obtain the dispersible covalent triazine skeleton.

[0045] An embodiment of the present invention provides a dispersible covalent triazine skeleton, wherein the dispersible covalent triazine skeleton is prepared by using the preparation method of the dispersible covalent triazine skeleton.

[0046] The dispersible covalent triazine skeleton described in the embodiment of the present invention can be dispersed in a dispersing solvent, and the dispersing solvent includes one or more of ethanol, dichloromethane, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, ethyl acetate, ether, ethyl bromide, tetrahydrofuran, pyridine, acetone, propanol, dioxane, methyl ethyl ketone, n-butanol, carbon tetrachloride, carbon disulfide, cyclohexane, hexane, triethylamine, petroleum ether, benzene, toluene, xylene, 2-pyrrolidone, N-methyl-2-pyrrolidone, methyl tert-butyl ether, ethylene glycol dimethyl ether, kerosene, etc.

[0047] The embodiment of the present invention provides an application of the dispersible covalent triazine skeleton in the preparation of an organic gel or an aerogel.

[0048] In one embodiment, the step of preparing the organogel comprises:

[0049] Dispersing dispersible CTF in a dispersing solvent to obtain a CTF mixed solution; wherein the dispersing solvent includes one or more of ethanol, dichloromethane, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, ethyl acetate, ether, ethyl bromide, tetrahydrofuran, pyridine, acetone, propanol, dioxane, methyl ethyl ketone, n-butanol, carbon tetrachloride, carbon disulfide, cyclohexane, hexane, triethylamine, petroleum ether, benzene, toluene, xylene, 2-pyrrolidone, N-methyl-2-pyrrolidone, methyl tert-butyl ether, ethylene glycol dimethyl ether, and kerosene;

[0050] The CTF mixed solution is allowed to stand for 1 min to 120 h (such as 1 min, 30 min, 1 h, 24 h, 40 h, 60 h, 80 h, 100 h, 120 h, etc.) to form a gel to obtain an organogel.

[0051] In one embodiment, the step of preparing the aerogel comprises:

[0052] The dispersible CTF, the dispersing solvent and the functional material are blended to obtain a blended liquid; preferably, the functional material comprises carbon nanotubes CNT, graphene, graphyne, graphite, fullerene, MXene, silicon dioxide, titanium dioxide, zirconium oxide, vanadium oxide, polyurethane, polyurea, polyimide, polystyrene, polyamide, polyvinylidene chloride, polypyrrole, polybenzoic acid, One or more of oxazine, metal gold, silver, platinum, palladium, iridium, copper, iron, magnesium, aluminum, titanium, tin, lead, manganese and metal oxides thereof;

[0053] The mixed liquid is allowed to stand for 1 min to 120 h (such as 1 min, 30 min, 1 h, 24 h, 40 h, 60 h, 80 h, 100 h, 120 h, etc.) to form a gel, and then the dispersion solvent is evaporated or removed by drying to obtain an aerogel.

[0054] An embodiment of the present invention provides an application of the dispersible covalent triazine skeleton as a catalyst.

[0055] In the embodiment of the present invention, under certain temperature, catalyst and solvent conditions, a phthalonitrile monomer having a para-symmetrical structure and a phthalonitrile monomer having a para-asymmetric structure can be prepared by a one-pot method to obtain partially crystalline CTF. The partially crystalline CTF (i.e., dispersible CTF, also known as solvent-stripped CTF) can be dispersed in a solvent such as N,N-dimethylformamide (DMF) and used for preparing organic gels, aerogels and catalysis. See Figure 1 shown.

[0056] Phthalonitrile monomers with para-symmetric structures, such as terephthalonitrile (TPN), react with trifluoromethanesulfonic acid (TfOH) to form nitrile salts, and then undergo a series of nucleophilic reactions on this basis to form triazine units, which form CTF through extremely strong van der Waals forces. Phthalonitrile monomers with para-asymmetric structures, such as methyl terephthalonitrile (MTPN), also react similarly to form triazine units, which form CTF through weaker van der Waals forces. CTF synthesized with different proportions of MTPN has an asymmetric layer formed inside the material, and amorphous regions and random stacking are introduced into the CTF layer, which is conducive to the solvent to open the stacking through capillary action and surface energy differences, thereby peeling off the CTF and achieving the dispersion of CTF in the solvent.

[0057] The present invention is further described in detail below through several specific embodiments.

[0058] Example 1

[0059] 0.6 g of monomer TPN, 3 g of super acid catalyst TfOH, and 6 g of dichloromethane (DCM) were mixed evenly to obtain a reaction solution. The reaction solution was placed in a shaker at a shaking rate of 50 rpm, and reacted at room temperature of 25°C for 24 hours, centrifuged to precipitate the product at the bottom, removed the supernatant, and vacuum dried to obtain a crystalline covalent triazine framework CTF (referred to as CTF1).

[0060] The obtained crystalline covalent triazine framework CTF was characterized and simulated, including DFT calculations and DMF solubility tests.

[0061] Example 2

[0062] 0.6 g of monomer MTPN, 3 g of super acid catalyst TfOH, and 6 g of dichloromethane (DCM) were mixed evenly to obtain a reaction solution. The reaction solution was placed in a shaker at a shaking rate of 50 rpm, and reacted at room temperature of 25°C for 24 hours, centrifuged to precipitate the product at the bottom, removed the supernatant, and vacuum dried to obtain a covalent triazine framework CTF (referred to as MTPN 100%).

[0063] The obtained covalent triazine skeleton CTF was characterized, including DMF solubility test, XRD test, etc.

[0064] Example 3

[0065] 0.15g of monomer TPN and 0.45g of monomer MTPN, 3g of superacid catalyst TfOH, and 6g of dichloromethane were mixed evenly to obtain a reaction solution. The reaction solution was placed in a shaker at a shaking rate of 50rpm, and reacted at room temperature of 25°C for 24h, centrifuged to precipitate the product at the bottom, removed the supernatant, and vacuum dried to obtain a covalent triazine framework CTF (referred to as MTPN75%).

[0066] The obtained covalent triazine skeleton CTF was characterized, including DMF solubility test and static experimental observation, and the rheological property test of the obtained organic gel was carried out, and the obtained aerogel was observed by SEM. The results are shown in the attached figure.

[0067] Specifically, the product was dispersed in DMF to prepare a 5wt% dispersion and allowed to stand for 12 hours to observe the gelation process of the material and test the rheological properties. 10 mL of the dispersion was taken, 2 g of multi-walled carbon nanotubes MWCNT were added to the dispersion, the solvent evaporated after stirring, and an aerogel was obtained. The morphology of the aerogel was observed by SEM.

[0068] Example 4

[0069] 0.225g of monomer TPN and 0.375g of monomer MTPN, 3g of superacid catalyst TfOH, and 6g of dichloromethane were mixed evenly to obtain a reaction solution. The reaction solution was placed in a shaker at a shaking rate of 50rpm, and reacted at room temperature of 25°C for 24h, centrifuged to precipitate the product at the bottom, removed the supernatant, and vacuum dried to obtain a covalent triazine framework CTF (referred to as MTPN62.5%).

[0070] The obtained product was characterized, including DMF solubility test, XRD test, etc. The results are shown in the attached figure.

[0071] The obtained product is dispersed in DMF to prepare a 5wt% dispersion, which can be used to photodegrade the dye. For example, when methylene blue is added to the dispersion and the initial concentration of methylene blue is 0.1 mol / L, the photodegradation rate of methylene blue is 99% after 2 minutes of UV light irradiation, showing extremely high photodegradation activity. Compared with triazine skeleton powder or triazine skeleton film, the catalytic photodegradation efficiency is significantly improved.

[0072] The CTF synthesis feeding scheme of the above-mentioned Examples 1 to 4 is shown in Table 1 below.

[0073] Table 1. CTF synthesis feeding scheme

[0074]

[0075] Figure 2 This is the DFT calculation process of the synthesis of CTF1 from TPN monomer. For TPN, the reaction starts from the protonated TPN cation (Int_0), which reacts with TPN molecules to form dimer and trimer states. Under acidic conditions, it reorganizes into triazine nitrile cation (Int_4) to release higher energy (ΔG total =-25.1 kcal·mol -1 ) and serves as the driving force of the entire process. Ultimately, the Tf+ substituent in Int_4 falls off to form a stable triazine structure (Pro). The total free energy change is -23.6 kcal·mol -1 , indicating that under this condition, the formation of triazine structure is favorable.

[0076] Figure 3 The X-ray diffraction (XRD) diagram of the product obtained in Example 2-4 is shown in FIG. Figure 3It can be seen that MTPN100% shows strong and narrow peaks at 7.8°, 14.1° and 26.1°, corresponding to the in-plane (100) plane, (110) plane and interlayer diffraction, respectively. These results indicate good crystallinity and the presence of filled holes in the crystal network. In contrast, MTPN75% and MTPN62.5% show weakened (100) planes and shifted, widened (110) planes, indicating obvious stacking damage and crystal structure damage. In addition, the relative intensity of the in-plane diffraction peaks decreases and the full width at half maximum increases (2.4° to 4.3° to 6.6°), indicating that the grain size gradually decreases.

[0077] Figure 4 It shows that the prepared CTF1 cannot be dispersed in DMF, but deposited at the bottom, while MTPN100%, MTPN75% and MTPN62.5% can all be dispersed in DMF.

[0078] Figure 5 The viscosity and shear rate curves are shown before and after the dispersion forms the organic gel at the initial stage (0 h) and after standing for 12 h. Figure 5 a), and the storage modulus (G') and loss modulus (G") versus frequency ( Figure 5 b), the results all show that after standing for 12 hours, the organic gel is formed, and its storage modulus and viscosity values ​​are increased. Aerogel can be prepared by modifying multi-walled carbon nanotubes (MCNT) with MTPN75% dispersion ( Figure 5 c), and the aerogel was observed by SEM. The results are shown in Figure 5 Middle d.

[0079] In summary, the present invention provides a dispersible covalent triazine skeleton and a preparation method and application thereof. Under certain temperature, catalyst and solvent conditions, the present invention can prepare partially crystalline CTF by a one-pot method from phthalonitrile monomers with a para-symmetrical structure and phthalonitrile monomers with a para-asymmetric structure. The partially crystalline CTF (i.e., dispersible CTF) can be dispersed in solvents such as N,N-dimethylformamide (DMF) and used for preparing organic gels, aerogels and catalysis.

[0080] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a dispersible covalent triazine skeleton, characterized in that: Includes steps: Providing nitrile monomers, the nitrile monomers comprising phthalonitrile monomers having a para-symmetrical structure and phthalonitrile monomers having a para-asymmetric structure, wherein the mass percentage of the phthalonitrile monomers having a para-asymmetric structure is 0.001% to 100% of the nitrile monomers; mixing the nitrile monomer, a catalyst and a solvent to obtain a reaction solution; The reaction solution is reacted to obtain the dispersible covalent triazine skeleton.

2. The method for preparing a dispersible covalent triazine framework according to claim 1, characterized in that: The phthalonitrile monomers having a para-symmetric structure include one or more of terephthalonitrile, tetrachloroterephthalonitrile, tetrafluoroterephthalonitrile, and 4,4'-biphenylcarbonitrile.

3. The method for preparing a dispersible covalent triazine framework according to claim 1, characterized in that: The phthalonitrile monomers having a para-asymmetric structure include one or more of methyl terephthalonitrile, 2-ethynyl terephthalonitrile, ethyl terephthalonitrile, hydroxy terephthalonitrile, isophthalonitrile, phthalonitrile, 4-propoxy phthalonitrile, tetrafluorophthalonitrile, 3,6-dihydroxyphthalonitrile, 4,5-dichlorophthalonitrile, diethyl phthalonitrile, 4-p-aminophenoxyphthalonitrile, 4-(2',6'-dimethylphenoxy)phthalonitrile, 3-nitrophthalonitrile, 4-hexyloxyphthalonitrile, 3-chlorophthalonitrile, 4,5-dichlorophthalonitrile, tetrachlorophthalonitrile, tetrafluorophthalonitrile, 5-chloro-2,4,6-trifluoroisophthalonitrile, and 4-n-dodecyloxyphthalonitrile.

4. The method for preparing a dispersible covalent triazine framework according to claim 1, characterized in that: The catalyst includes one or more of trifluoromethanesulfonic acid, magic acid, fluorosulfonic acid, fluoroantimonic acid, carborane acid, and piranha solution.

5. The method for preparing a dispersible covalent triazine framework according to claim 1, characterized in that: The solvent includes one or more of ethanol, dichloromethane, chloroform, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, ethyl acetate, ether, ethyl bromide, tetrahydrofuran, pyridine, acetone, propanol, dioxane, methyl ethyl ketone, n-butanol, carbon tetrachloride, carbon disulfide, cyclohexane, hexane, triethylamine, petroleum ether, benzene, toluene, xylene, 2-pyrrolidone, N-methyl-2-pyrrolidone, methyl tert-butyl ether, ethylene glycol dimethyl ether, and kerosene.

6. The method for preparing a dispersible covalent triazine framework according to claim 1, characterized in that: The mass ratio of the nitrile monomer, the catalyst and the solvent is 1:(0.01-1000):(0.01-1000).

7. The method for preparing a dispersible covalent triazine framework according to claim 1, characterized in that: The reaction temperature is a temperature between -10 and 100°C.

8. The method for preparing a dispersible covalent triazine framework according to claim 1, characterized in that: The reaction time is 5 min-120 h.

9. A dispersible covalent triazine framework, characterized in that The polyol is prepared by the method for preparing the dispersible covalent triazine skeleton according to any one of claims 1 to 8.

10. Use of the dispersible covalent triazine framework according to claim 9 in the preparation of an organic gel or an aerogel; Alternatively, use of the dispersible covalent triazine framework as claimed in claim 9 as a catalyst.

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