High specific surface polyurea self-microporous material and preparation method thereof

Abstract

The application discloses a kind of high specific surface polyurea self microporous material and preparation method thereof, it is with acetone, acetonitrile and so on Organic solvent or its mixture with water as reaction medium, using rigid and twisted structure polyisocyanate and polyamine as monomer, is prepared by step polymerization.The application does not need emulsifier and catalyst and other substances, monomer is completely converted after polymerization, reaction time is not more than 2 hours, and polymerization reaction can be carried out under the condition of static not stirring, without any stirring or oscillation equipment, cost and energy consumption are lower, production efficiency is high, it is conducive to the realization of self microporous material's large-scale production and application.The product is post-treated using supercritical liquid extraction technology, so that the specific surface area of material is significantly improved.The yield of polyurea self microporous material prepared by the application is greater than 95.0%, the specific surface area is between 500-900 m 2 / g, and the average pore size is 0.6-2.0 nm.

Description

Technical Field

[0001] This invention relates to a self-contained microporous material, specifically a high specific surface area polyurea self-contained microporous material and its preparation method. It belongs to the technical field of functional polymer materials. Background Technology

[0002] Self-contained microporous polymers (PIMs) are a novel type of amorphous microporous material with a rigid, twisted molecular structure. Their chain segments cannot rotate freely, hindering the effective stacking of macromolecular chains and promoting the formation of a continuous microporous structure within the polymer. Compared to other types of organic porous polymers, PIMs exhibit excellent film-forming properties and can be processed into robust films, fibers, or coatings. They have found wide application in fields such as chemical catalysis, liquid-phase separation, wastewater treatment, gas membrane separation, and hydrogen storage.

[0003] Currently, existing reports all describe the preparation of PIMs using functional monomers containing twisted and rigid structures. Based on the different types of rigid and twisted units, PIMs can be classified into: spirocyclic units (Spiro), tripterene units (Trip), and Tröger base units (Tröger Base), etc.

[0004] Budd PM et al. (Adv. Mater., 2004, Vol. 16, pp. 456-459) prepared the first self-microporous polymer material PIM-1 by reacting a tetrahydroxy monomer containing a spirocyclic ring and a monomer containing a rigid tetrafluorophenyl at 65 °C for 72 h.

[0005] McKeown NB et al. (Adv. Mater., 2012, Vol. 24, pp. 5930–5933) synthesized a PIM containing a bisphenylfluorene spirocyclic structure, which requires a reaction at 65 °C for 95 h.

[0006] Mariolino C et al. (Polym. Chem., 2014, Vol. 5, pp. 5262–5266) prepared PIM using 2,6,14-triamino-9,10-dimethyltriptene as a functional monomer. The reaction was carried out under nitrogen atmosphere for 72 h, followed by a 32 h post-treatment to obtain a brown powder with a yield of 89.1%.

[0007] Ainur Y et al. (J. Membr. Sci., 2020, Vol. 595, pp. 117512) prepared a functionalized self-contained microporous polyimide by reacting 4,4-hexafluoroisopropenyl phthalic anhydride and 2,6(7)-dihydroxy-3,7(6)-diaminotriptene at 200 °C for 4 h. After drying and heat treatment (>30 h), the specific surface area of ​​the polymer increased from 167 m² / h. 2 / g increased to 405 m2 / g.

[0008] Luo S et al. (ACS Appl. Mater. Interfaces, 2018, Vol. 10, pp. 15174–15182) prepared a crude product by reacting pentaphyllendiol and dimethoxymethane as monomers at 80 °C for 24 h. After Soxhlet extraction for 24 h, the crude product was dried at 120 °C for 24 h to obtain PIM containing pentaphyllendiol.

[0009] Zhang G et al. (J. Membr. Sci., 2018, Vol. 556, pp. 277–284) prepared PIM containing tripterene and tergler base units by copolymerizing 2,6-diamino-14-carboxytriptene and 2,6-diaminotriptene. The entire process took at least 5 days and the yield was about 70%.

[0010] Patent CN110862537B first prepares a biphenylamine monomer via a Diels-Alder reaction of 2,6-diaminoanthracene with maleimide or its derivatives, then uses a Tergler base reaction to induce polycondensation of the biphenylamine monomer, and finally removes the maleimide or its derivatives to obtain PIM. The entire process requires at least 18 hours, and the specific surface area of ​​the product is between 50 and 800 m². 2 Between / g.

[0011] In summary, existing methods for preparing PIMs involve cumbersome steps, high reaction temperatures, and long reaction times (≥18 h), while the specific surface area is usually low.

[0012] Polyurea possesses high melting point, high strength, good toughness, and excellent heat and corrosion resistance. Furthermore, the raw materials for its preparation are widely available, and the reaction conditions are mild and the reaction rate is relatively fast. Currently, there are no reports of polyurea materials with inherent microporous structures. Summary of the Invention

[0013] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high specific surface area polyurea material with microporous structure and its preparation method, which is simple, fast and efficient.

[0014] To achieve the above objectives, the present invention adopts the following technical solution:

[0015] 1. A method for preparing a high specific surface area polyurea self-contained microporous material, comprising the following steps: first, dissolving a polyisocyanate monomer and a polyamine monomer containing a rigid tortuous structure in a reaction medium; then, carrying out a polymerization reaction in a constant temperature water bath to obtain a reaction product; finally, alternatingly treating the reaction product with supercritical liquid extraction and organic solvent soaking to obtain the polyurea self-contained microporous material with a specific surface area between 500 and 900 m². 2 The average pore size is between 0.6 and 2.0 nm.

[0016] Preferably, the polymerization reaction process conditions are: reaction temperature 20-80℃, stirring rate 0-300 r / min, and stirring time 10-240 minutes.

[0017] Further preferred methods include a reaction temperature of 25–70°C, a stirring rate of 0–200 r / min, and a stirring time of 30–120 minutes.

[0018] Preferably, the total amount of polyisocyanate monomer and polyamine monomer is 1.0 to 40.0% of the total mass of the whole system, more preferably 5.0 to 30.0%; the molar ratio of isocyanate groups in the polyisocyanate monomer to amine groups in the polyamine monomer is 0.7 to 1.3:1, more preferably 0.9 to 1.1:1.

[0019] Preferably, the polyisocyanate monomer is selected from any one of the following: phenyl diisocyanate, toluene diisocyanate, isophthalimide diisocyanate, naphthalene diisocyanate, 4,4-diphenylmethane diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, 2,2-bis(4-phenyl isocyanate)hexafluoropropane, and triterene diisocyanate.

[0020] Preferably, the polyamine monomer is selected from any one of the following: 4,4'-diamino-3,3'-dimethyldiphenylmethane, 5(6)-1-(4-aminophenyl)-1,3,3'-trimethylindene, 9,9'-spirobis[9H-fluorene]-2,2'-diamine, 5,5'-diamino-3,3,3',3'-tetramethyl-1,1'-spirobisindene, 5,5',6,6'-tetraamino-3,3,3',3'-tetramethyl-1,1'-spirobisindene, 4,4'-diaminotriphenylamine, 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl, 2,8-dimethyl-6H,12H-5,11-methylenedibenzo[B,F][1,5]diazopentanol, and 2,6-diaminoanthraquinone.

[0021] Preferably, the reaction medium is acetonitrile, acetone, butanone, dimethyl sulfoxide, pyridine, tetrahydrofuran, N,N'-dimethylformamide, or / and N,N'-dimethylacetamide.

[0022] Preferably, the reaction medium is a mixture of an organic solvent and water, wherein the water accounts for less than 40% by mass, and the organic solvent is acetonitrile, acetone, butanone, dimethyl sulfoxide, pyridine, tetrahydrofuran, N,N'-dimethylformamide, or / and N,N'-dimethylacetamide.

[0023] Preferably, the alternating treatment method is as follows: the reaction product is placed in a sealed container and supercritical CO2 is introduced. After extraction at 30-50 °C and 8-50 MPa for 5-20 minutes, the gas is released to obtain a solid. The solid is soaked in an organic solvent and then extracted and released again. This process is repeated 1-3 times. The organic solvent is acetone or acetonitrile.

[0024] 2. A high specific surface area polyurea material with microporous structure is prepared by the aforementioned method.

[0025] The beneficial effects of this invention are:

[0026] This invention uses organic solvents such as acetone and acetonitrile, or mixtures thereof with water, as the reaction medium. It employs polyisocyanates and polyamines with rigid and tortuous structures as monomers to prepare polyurea self-contained microporous materials through stepwise polymerization. This invention eliminates the need for emulsifiers and catalysts, ensures complete monomer conversion after polymerization, and completes the reaction within 4 hours. Furthermore, the polymerization reaction can be carried out under static, unstirred conditions, requiring no stirring or agitation equipment. This results in lower cost and energy consumption, higher production efficiency, and facilitates the large-scale production and application of self-contained microporous materials. Supercritical liquid extraction technology is used for post-treatment of the product, significantly increasing the specific surface area of ​​the material. The yield of polyurea self-contained microporous materials prepared by this invention is greater than 95.0%, with a specific surface area of ​​500–900 m². 2 The average pore size ranges from 0.4 to 2.0 nm. The specific surface area and pore structure of the product can be adjusted by regulating the ratio and amount of monomer and solvent, reaction temperature, and other conditions to meet the material performance requirements of different applications.

[0027] The applicant has been engaged in the preparation and characterization of porous polymer materials, focusing on improving the specific surface area of ​​porous materials. In previous work (Journal of Chemical Research in Chinese Universities, 2013, Vol. 34, pp. 992-999; CN103819650B), the applicant synthesized polyurea porous materials (PPU) in a mixed solvent of water and acetone, using toluene diisocyanate or a mixture of 2-4 isocyanates as monomers, based on their reaction with water. This material does not contain micropores smaller than 2 nm, but mainly consists of mesopores of 3-5 nm and macropores larger than 100 nm, with a surface area not exceeding 190 m². 2 / g. The PPU exhibits a relatively large pore size and low specific surface area, which is related to its chemical structure. Due to the use of aromatic isocyanate monomers containing benzene rings and strong hydrogen bonding between urea groups, the resulting PPU molecular chains have strong rigidity and interactions, causing them to attract each other and aggregate into fibrous aggregates. Because no functional monomers with twisted structures are introduced, the PPU molecular chains are tightly packed, resulting in no gaps between chains and no microporous structure. The internal mesopores and macropores are formed by the overlapping of fibrous aggregates. Due to the large pore size, the PPU has a low specific surface area. The applicant has also conducted experiments under the same conditions using aliphatic isocyanate monomers without benzene rings (such as isophorone diisocyanate), obtaining polymer microspheres with smooth surfaces and no pores (CN102643402B, CN102702470B, and CN104072719B), which also indicates that the porous structure of PPU is related to its rigid structure (benzene rings). When aliphatic isocyanate monomers are used, the introduction of non-rigid alkyl chains increases the flexibility of the polyurea molecular chains, resulting in a more compact arrangement and stacking of the chains, thus eliminating the porous structure. It is well known that polyurea materials can be prepared not only by the reaction of isocyanates with water, but also by the reaction of isocyanates with aliphatic polyamines. The applicant has also prepared cross-linked polyureas using polyisocyanates and aliphatic amines such as triethylenetetramine as monomers in mixed solvents of water / acetonitrile or water / acetone (CN106317358B; RSC Adv., 2014, Vol. 4, pp. 32134–32141). The results showed that regardless of whether the polyisocyanate monomer contained a rigid structure, the product obtained by reacting it with aliphatic polyamines was a smooth polyurea microsphere without a porous structure. This indicates that it is also impossible to prepare porous materials using rigid isocyanates and conventional polyamine monomers. The reason may be that the introduction of aliphatic polyamines increases the flexibility of the polyurea molecular chains, making it easier for the molecular chains to adjust their conformation and arrange and stack more tightly, making it difficult to form pores.

[0028] The applicant recently attempted to react Tegler base with polyisocyanate and found that the surface area of ​​the resulting material far exceeded expectations (>500 m²). 2 / g), unexpected results were obtained. Based on this, the applicant systematically optimized the experimental conditions of the system, including the types, amounts, and ratios of the polyisocyanate and polyamine monomers containing rigid tortuous structures, the types, amounts, and ratios of solvents, reaction temperature, and stirring rate. Through numerous creative experiments, the specific surface area of ​​the material reached 900 m². 2 / g. Significantly different from other works mentioned above, this invention, in preparing polyurea porous materials, uses not only isocyanate monomers with rigid structures but also polyamine monomers with rigid and twisted structures. The rigid structure in the molecule prevents chain segments from rotating freely, while the twisted structure hinders the close packing of macromolecular chains, promoting the formation of a continuous microporous structure (<2 nm) within the polyurea, which endows the material with a high specific surface area. The resulting polyurea is a typical self-microporous material. The structure and type of the raw materials used, as well as the pore-forming mechanism, are substantially different from other polyurea porous materials mentioned above. Moreover, there are no reports on self-microporous polyurea materials in existing literature or patent documents, and no relevant methods or technical inspirations are available for reference. Compared with existing methods for preparing PIM, the method of this invention requires only a single raw material, operates under low temperature conditions (20~80 °C, static or stirring rate below 300 r / min), has a short reaction time (<4 h), and produces a product with a high specific surface area (900 m²). 2 In summary, this invention has significant inventiveness.

[0029] Supercritical liquid extraction (SLI) is a novel chemical separation technology that has emerged in the last 30 years and has been widely applied in many fields. The applicant discovered that using SLI significantly increases the specific surface area of ​​the resulting microporous polyurea material. Supercritical liquids (such as CO2) can extract the reaction medium in the system. During the venting process, the solvent is rapidly released with the CO2, which shortens the desolvation time of the polyurea molecular chains during drying. This prevents the molecular chains from fully relaxing their conformation, resulting in a looser packing effect, which is beneficial for increasing the specific surface area of ​​the material. The applicant optimized the conditions of supercritical extraction (including temperature, pressure, and time) through numerous experiments and compared the results with those obtained without this technology. The results showed that when the product was post-processed using conventional methods (including centrifugation, washing, and drying steps, see comparative example), the yield of the obtained microporous polyurea material was 95.4%, and the specific surface area was 695 m². 2 / g (which is already significantly higher than the specific surface area of ​​the polyurea porous material we previously reported, namely 190 m² in CN103819650B). 2 The average pore size was 1.5 nm, while when post-processed using supercritical liquid extraction (Example 3), the yield of the polyurea self-contained microporous material was 98.5%, and the specific surface area was 890 m² / g. 2 The average pore size was 0.6 nm. This demonstrates that the specific surface area of ​​the product was further increased after supercritical liquid extraction.

[0030] The specific advantages are as follows:

[0031] 1. Existing technologies require monomers with complex structures, cumbersome operation steps, and long processing times when preparing PIMs. The rigid twisted polyamine required by this invention is a commonly used monomer in the preparation of PIMs. The required polyisocyanate monomer is already in industrial production, and it has the advantages of readily available raw materials, mild reaction conditions, simple operation, and fast reaction rate. The entire process takes as little as 1 hour, which is significantly more advantageous than previous methods (>18 hours) and facilitates the large-scale production of PIMs.

[0032] 2. The polymerization reaction of the present invention can be carried out without stirring or shaking. The reactor can be placed in a constant temperature water bath without any stirring or shaking equipment, which significantly reduces equipment cost and energy consumption. At the same time, the monomer dosage can reach 40% and can be completely converted (100%) when preparing polyurea PIMs, and the yield of PIMs is also high.

[0033] 3. The method of this invention introduces supercritical fluid extraction technology into the preparation process of microporous materials, thereby significantly increasing their specific surface area (up to 900 m²). 2 / g (see Example 3 and Comparative Example), and the surface of the obtained PIMs is rich in amino groups, which have a strong interaction with CO2 gas, making them potentially applicable in the fields of selective adsorption and separation of gases. Detailed Implementation

[0034] The present invention will be further described below with reference to embodiments. It should be noted that the following description is only for explaining the present invention and does not limit its content.

[0035] Example 1

[0036] At room temperature, 95.0 g of acetone was first added to a 120 mL reaction flask, followed by 2.79 g of 5(6)-1-(4-aminophenyl)-1,3,3'-trimethylindene and 2.21 g of naphthalene diisocyanate (NCO / NH2=1.0). After shaking to ensure homogeneity, the reaction flask was placed in a constant temperature water bath at 30 °C and reacted for 120 min at a stirring rate of 60 r / min. After the reaction was completed, the product was placed in a sealed container and supercritical CO2 was introduced. Extraction was performed at 40 °C and 40 MPa for 5 min, followed by venting. The resulting solid was then soaked in acetone and extracted and vented again. This process was repeated twice to obtain a high specific surface area polyurea material with its own microporous structure.

[0037] The yield of the obtained polyurea microporous material was 98.4%, and the specific surface area was 850 m². 2 / g, with an average pore size of 0.7nm.

[0038] Example 2

[0039] At room temperature, 90.0 g of a 5 / 5 acetone / acetonitrile mixture was added to a 120 mL reaction flask, followed by 4.28 g of 4,4'-diamino-3,3'-dimethylphenylmethane and 5.72 g of triterene diisocyanate (NCO / NH2=0.90). After shaking thoroughly, the reaction flask was placed in a 70 °C water bath for 30 min. After the reaction was complete, the product was placed in a sealed container and supercritical CO2 was introduced. Extraction was performed at 40 °C and 40 MPa for 5 min, followed by venting. The resulting solid was then soaked in acetonitrile and extracted and vented again. This process was repeated three times to obtain a high specific surface area polyurea microporous material.

[0040] The yield of the obtained polyurea microporous material was 98.7%, and the specific surface area was 712 m². 2 / g, with an average pore size of 0.8nm.

[0041] Example 3

[0042] At room temperature, 90.0 g of a 1 / 9 water / N,N'-dimethylformamide mixed solvent was added to a 120 mL reaction flask, followed by 5.86 g of 9,9'-spirodi[9H-fluorene]-2,2'-diamine and 4.14 g of triphenylmethane triisocyanate (NCO / NH2=1.0). After shaking thoroughly, the reaction flask was placed in a 50°C constant temperature water bath and reacted for 60 min with a stirring rate of 120 r / min. After the reaction was completed, the product was placed in a sealed container and supercritical CO2 was introduced. Extraction was performed at 40°C and 40 MPa for 5 min, followed by venting. The resulting solid was then soaked in acetonitrile and extracted and vented again. This process was repeated twice to obtain a high specific surface area polyurea self-contained microporous material.

[0043] The yield of the obtained polyurea microporous material was 98.5%, and the specific surface area was 890 m². 2 / g, with an average pore size of 0.6nm.

[0044] Example 4

[0045] At room temperature, 80.0 g of N,N'-dimethylformamide, 8.41 g of 5,5'-diamino-3,3,3',3'-tetramethyl-1,1'-spirobisindane, and 11.59 g of 2,2-bis(4-phenylisocyanate)hexafluoropropane (NCO / NH2=1.1) were added to a 120 mL reaction flask. After shaking thoroughly, the reaction flask was placed in a constant temperature water bath at 50 °C for 60 min. After the reaction was completed, the product was placed in a sealed container and supercritical CO2 was introduced. Extraction was carried out at 35 °C and 30 MPa for 10 min, followed by venting. The resulting solid was soaked in acetone and then extracted and vented again. This process was repeated three times to obtain a high specific surface area polyurea material with its own microporous structure.

[0046] The yield of the obtained polyurea self-contained microporous material was 99.5%, and the specific surface area was 810 m². 2 / g, with an average pore size of 0.7nm.

[0047] Example 5

[0048] At room temperature, 85.0 g of acetonitrile, 8.36 g of 2,6-diaminoanthraquinone, and 6.64 g of naphthalene diisocyanate (NCO / NH2=0.9) were added to a 120 mL reaction flask. After shaking and mixing, the flask was placed in a constant temperature water bath at 80℃ for 15 min. After the reaction was completed, the product was placed in a sealed container and supercritical CO2 was introduced. Extraction was carried out at 35℃ and 20 MPa for 15 min, followed by venting. The resulting solid was then soaked in acetonitrile and extracted and vented again. This process was repeated once to obtain a high specific surface area polyurea with its own microporous structure.

[0049] The yield of the obtained polyurea microporous material was 100%, and the specific surface area was 540 m². 2 / g, with an average pore size of 1.6nm.

[0050] Example 6

[0051] At room temperature, 70.0 g of dimethyl sulfoxide, 18.97 g of 4,4'-diaminotriphenylamine, and 11.03 g of phenyl diisocyanate (NCO / NH2=1.0) were added to a 120 mL reaction flask. After shaking thoroughly, the flask was placed in a constant temperature water bath at 50 °C and reacted for 60 min at a stirring rate of 200 r / min. After the reaction was completed, the product was placed in a sealed container and supercritical CO2 was introduced. Extraction was carried out at 30 °C and 20 MPa for 20 min, followed by venting. The resulting solid was then soaked in acetone and extracted and vented again. This process was repeated three times to obtain a high specific surface area polyurea with its own microporous structure.

[0052] The yield of the obtained polyurea microporous material was 98.3%, and the specific surface area was 502 m². 2 / g, with an average pore size of 1.8nm.

[0053] To compare with the material obtained by post-processing with supercritical CO2 according to the present invention (Example 3), a comparative example of post-processing the product using conventional methods is given below.

[0054] Comparative Example

[0055] Stepwise polymerization was carried out using the same formulation and steps as in Example 3: At room temperature, 90.0 g of a water / N,N'-dimethylformamide mixed solvent with a mass ratio of 1 / 9 was first added to a 120 mL reaction flask, followed by 5.86 g of 9,9'-spirobis[9H-fluorene]-2,2'-diamine and 4.14 g of triphenylmethane triisocyanate (NCO / NH2=1.0). After shaking evenly, the reaction flask was placed in a constant temperature water bath at 50°C and reacted for 60 min at a stirring rate of 120 r / min.

[0056] The product was post-processed using conventional methods: after the reaction was completed, the system was separated by centrifugation at 8000 r / min for 10 min. After removing the supernatant, the product was washed with acetonitrile and centrifuged again. This process was repeated twice. The resulting product was then dried in an 85 ℃ constant temperature oven for 8 h to obtain the polyurea self-porous material.

[0057] The yield of the obtained polyurea microporous material was 95.4%, and the specific surface area was 695 m². 2 / g, with an average pore size of 1.5nm.

[0058] Compared with Example 3, the comparative example had a longer post-processing time, significantly lower yield and specific surface area, and larger pore size.

[0059] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Based on the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A method for preparing a high specific surface area polyurea self-contained microporous material, characterized in that, The specific steps are as follows: First, the polyisocyanate monomer and polyamine monomer containing the rigid twisted structure are dissolved in the reaction medium. Then, a polymerization reaction is carried out in a constant temperature water bath to obtain the reaction product. Finally, the reaction product is treated alternately by supercritical liquid extraction and organic solvent soaking to obtain the polyurea microporous material with a specific surface area between 500 and 900 m². 2 The average pore size is between 0.6 and 2.0 nm; the polyisocyanate monomer containing the rigid twisted structure is triterene diisocyanate.

2. The preparation method according to claim 1, characterized in that, The polymerization process conditions are: reaction temperature 20–80℃, stirring rate 0–300 r / min, and stirring time 10–240 minutes.

3. The preparation method according to claim 2, characterized in that, The reaction temperature is 25–70℃, the stirring speed is 0–200 r / min, and the stirring time is 30–120 minutes.

4. The preparation method according to claim 1, characterized in that, The total amount of polyisocyanate monomers and polyamine monomers containing rigid twisted structures is 1.0 to 40.0% of the total mass of the entire system; the molar ratio of isocyanate groups in the polyisocyanate monomers containing rigid twisted structures to amino groups in the polyamine monomers is 0.7 to 1.3:

1.

5. The preparation method according to claim 1, characterized in that, The polyamine monomer is selected from any one of the following: 4,4'-diamino-3,3'-dimethyldiphenylmethane, 5(6)-1-(4-aminophenyl)-1,3,3-trimethylindene, 9,9'-spirobis[9H-fluorene]-2,2'-diamine, 5,5'-diamino-3,3,3',3'-tetramethyl-1,1'-spirobisindene, 5,5',6,6'-tetraamino-3,3,3',3'-tetramethyl-1,1'-spirobisindene, 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl, 2,8-dimethyl-6H,12H-5,11-methylenedibenzo[B,F][1,5]diazopentanol, and 2,6-diaminoanthraquinone.

6. The preparation method according to claim 1, characterized in that, The reaction medium is acetonitrile, acetone, butanone, dimethyl sulfoxide, pyridine, tetrahydrofuran, N,N-dimethylformamide, or / and N,N-dimethylacetamide.

7. The preparation method according to claim 1, characterized in that, The reaction medium is a mixture of an organic solvent and water, wherein the water accounts for less than 40% by mass, and the organic solvent is acetonitrile, acetone, butanone, dimethyl sulfoxide, pyridine, tetrahydrofuran, N,N-dimethylformamide, or / and N,N-dimethylacetamide.

8. The preparation method according to claim 1, characterized in that, The specific method of alternating treatment is as follows: the reaction product is placed in a sealed container and supercritical CO2 is introduced. After extraction at 30-50 °C and 8-50 MPa for 5-20 minutes, the gas is released to obtain a solid. The solid is soaked in an organic solvent and then extracted and released again. This process is repeated 1-3 times. The organic solvent is acetone or acetonitrile.

9. A high specific surface area polyurea material with its own microporous structure, characterized in that, It is prepared by the method described in any one of claims 1 to 8.