Preparation method and application of a nitrogen-rich porous polymer

Abstract

The present invention discloses a preparation method and application of a nitrogen-rich porous polymer. The preparation method uses cyanuric chloride and p-nitrophenol to synthesize a monosubstituted nitro-phenoxy dichloro-s-triazine, and then reacts with carbazole under the activation of n-butyllithium to obtain a novel nitro-phenoxy dicarbazolyl-s-triazine monomer containing triazine and carbazole groups. Under the catalysis of aluminum chloride and dimethoxymethane for crosslinking, a hypercrosslinked porous polymer is obtained. Further, the nitro group in the polymer backbone is catalytically hydrogenated and reduced by Pd / C to generate amino groups, resulting in a hypercrosslinked nitrogen-rich porous polymer. The preparation method of the present invention is novel and efficient, the reactants are inexpensive and easily available, and the pore rate of the porous polymer is large and the specific surface area is high; the prepared hypercrosslinked nitrogen-rich porous polymer contains abundant nitrogen-containing functional groups such as carbazole, triazine and amino groups, has good intermolecular interaction and electrostatic adsorption effect on dyes such as methyl orange, and has a high adsorption capacity and good removal effect on dyes such as methyl orange.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material preparation, and particularly relates to a preparation method and application of a nitrogen-rich porous polymer. Background Art

[0002] Methyl orange wastewater is a kind of toxic wastewater, and the discharge of methyl orange wastewater comes from industries such as textile, plastic, paper-making, leather, etc. If it is directly discharged without treatment, it will not only cause color pollution to fresh water, but also a small amount of methyl orange will hinder the penetration of sunlight in water, thus seriously affecting the survival of organisms in water and destroying the ecological balance of organisms in water. Coupled with the high toxicity and carcinogenicity of methyl orange. Therefore, effectively treating methyl orange wastewater is of great significance to environmental protection and human health. At present, the treatment methods for methyl orange wastewater include: adsorption method, membrane separation method, oxidation method, electrochemistry method, biochemical method, etc.; among them, the adsorption method has the advantages of high efficiency, low cost, large operation flexibility, better effluent quality and insensitivity to toxic substances, and has become the focus of widespread attention.

[0003] Due to the large specific surface area, high porosity and rich active functional groups of porous polymers, they have broad application prospects in sewage treatment; for example, in "Removal of Methyl Orange in Aqueous Solution by Novel Aromatic Triazine Hypercrosslinked Porous Polymers" by He Yan et al., a novel aromatic triazine hypercrosslinked porous polymer was synthesized by the Friedel-Crafts alkylation method using nitrogen-containing triazine monomers, which can effectively remove methyl orange in aqueous solution; Ou Haijian et al. in "Synthesis, Modification and Adsorption Properties of Amine-Rich Porous Schiff Base Polymers", synthesized amine-rich porous Schiff base polymers by high-temperature polycondensation of melamine and terephthalaldehyde, and they have excellent adsorption capacities for methyl orange and 2,4-dichlorophenol. However, the preparation of these polymers has problems such as high preparation cost, difficult-to-obtain preparation raw materials, low adsorption capacity of the prepared polymers, and poor methyl orange removal effect.

[0004] In view of the above situation, it is necessary to study a preparation method and application of a nitrogen-rich porous polymer to solve the above technical problems. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a preparation method and application of a nitrogen-rich porous polymer to solve the above problems existing in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] In the first aspect of the present invention, a preparation method of a nitrogen-rich porous polymer is provided, including the following steps:

[0008] S1. Add cyanuric chloride and p-nitrophenol with a molar ratio of 1:1 to organic solvent A under an ice bath, then add an 8-10% aqueous sodium carbonate solution, stir and react for 1-3 h. After the reaction is completed, perform vacuum concentration to obtain concentrate A;

[0009] S2. Wash the concentrate A in S1 with deionized water and then recrystallize it with organic solvent A to obtain nitro-phenoxydichloro-s-triazine. The structural formula of the nitro-phenoxydichloro-s-triazine is:

[0010]

[0011] S3. Add the nitro-phenoxydichloro-s-triazine and carbazole in S2 to a tetrahydrofuran solution, and then dropwise add a tetrahydrofuran solution of n-butyllithium in a nitrogen atmosphere for reaction. After the reaction is completed, perform vacuum concentration to obtain concentrate B;

[0012] S4. Wash the concentrate B in S3 successively with deionized water and organic solvent B to obtain a precipitate; add the precipitate to organic solvent C for recrystallization to obtain nitro-phenoxydicarbazolyl-s-triazine. The structural formula of the nitro-phenoxydicarbazolyl-s-triazine is:

[0013]

[0014] S5: Add aluminum chloride, dimethoxymethane and trichloromethane solvent to the nitro-phenoxydicarbazolyl-s-triazine in S4 for reaction. After the reaction is completed, perform vacuum concentration to obtain concentrate C;

[0015] S6. Wash the concentrate C in S5 successively with deionized water, organic solvent A and organic solvent C to obtain a hypercrosslinked porous polymer. The structural formula of the hypercrosslinked porous polymer is:

[0016]

[0017] S7. Add the hypercrosslinked porous polymer in S6 to organic solvent C. After uniform dispersion, add a Pd / C catalyst for catalytic hydrogenation reduction reaction. After the reaction is completed, perform filtration. Wash the obtained filter cake with deionized water and organic solvent C to obtain a hypercrosslinked nitrogen-rich porous polymer. The structural formula of the hypercrosslinked nitrogen-rich porous polymer is:

[0018] Preferably, the organic solvent A is acetone, the organic solvent B is n-hexane, and the organic solvent C is ethanol.

[0019] Preferably, the molar ratio of the nitro-phenoxydichloro-s-triazine in S2 to the carbazole and n-butyllithium in S3 is 1:2-2.6:3.5-5.

[0020] Preferably, when adding nitro-phenoxydichloro-s-triazine and carbazole into a tetrahydrofuran solution in S3, and then dropping a tetrahydrofuran solution of n-butyllithium for reaction in a nitrogen atmosphere, the reaction conditions are refluxing at 60-75 °C for 6-12 h; the addition amount of the tetrahydrofuran solution is 150-200 mL.

[0021] Preferably, the molar ratio of nitro-phenoxydicarbazolyl-s-triazine, aluminum chloride and dimethoxymethane in S5 is 1:3.8-4.5:3.5-5.

[0022] Preferably, when reacting nitro-phenoxydicarbazolyl-s-triazine, aluminum chloride, dimethoxymethane and chloroform solvent in S5, the reaction conditions are refluxing at 75-85 °C for 20-30 h; the addition amount of the chloroform solvent is 50-100 mL.

[0023] Preferably, the dosage of the Pd / C catalyst in S7 is 7-12% of the mass of the hyper-crosslinked porous polymer.

[0024] In the second aspect of the present invention, there is provided an application of the nitrogen-rich porous polymer prepared by the preparation method of the nitrogen-rich porous polymer in the first aspect, and the application of the nitrogen-rich porous polymer in the adsorption and separation of methyl orange dye in wastewater treatment.

[0025] To sum up, compared with the prior art, the advantages of the present invention are as follows:

[0026] The present invention synthesizes mono-substituted nitro-phenoxydichloro-s-triazine by using cyanuric chloride and p-nitrophenol, and then reacts with carbazole under the activation of n-butyllithium to obtain a novel nitro-phenoxydicarbazolyl-s-triazine monomer containing triazine and carbazole groups; under the catalysis of aluminum chloride and dimethoxymethane for crosslinking, a hyper-crosslinked porous polymer is obtained; further, the nitro group in the hyper-crosslinked porous polymer skeleton is catalytically hydrogenated and reduced to amino by Pd / C to obtain a hyper-crosslinked nitrogen-rich porous polymer. The preparation method of the present invention is novel and efficient, the reactants are cheap and easy to obtain, and the pore size ratio of the porous polymer is large and the specific surface area is high; the prepared hyper-crosslinked nitrogen-rich porous polymer contains rich carbazole, triazine and amino nitrogen-containing functional groups, has good intermolecular interaction and electrostatic adsorption effect on dyes such as methyl orange, and has a high adsorption capacity and good removal effect on dyes such as methyl orange. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a reaction diagram of the preparation of the hyper-crosslinked nitrogen-rich porous polymer of the present invention.

[0028] Figure 2 is an infrared spectrum diagram of the hyper-crosslinked nitrogen-rich porous polymer prepared by the present invention.

[0029] Figure 3 It is the specific surface area and adsorption test chart of methyl orange by the porous polymer of the present invention. Detailed implementation manners

[0030] The present invention will be further described below.

[0031] Example 1

[0032] The preparation method of the nitrogen-rich porous polymer provided in this example includes the following steps:

[0033] S1. Add 0.73 g of cyanuric chloride and 0.56 g of p-nitrophenol to 10 mL of acetone solvent under ice bath, then add an aqueous solution of 8% sodium carbonate, stir and react for 1 h. After the reaction is completed, perform reduced pressure concentration. Wash the concentrate with deionized water and then add acetone for recrystallization to obtain nitro-phenoxy dichloro-s-triazine.

[0034] S2. Add 3 g of nitro-phenoxy dichloro-s-triazine and 3.5 g of carbazole to 150 mL of tetrahydrofuran solution, then dropwise add a tetrahydrofuran solution containing 2.8 g of n-butyllithium under a nitrogen atmosphere, and reflux and react at 70 °C for 12 h. After the reaction is completed, perform reduced pressure concentration. Wash the concentrate successively with deionized water and n-hexane, and then add the precipitate to ethanol for recrystallization to obtain nitro-phenoxy dicarbazolyl s-triazine.

[0035] S3. Add 1 g of nitro-phenoxy dicarbazolyl s-triazine, 1.1 g of aluminum chloride and 0.62 g of dimethoxymethane to 100 mL of chloroform solvent, reflux and react at 85 °C for 20 h. After the reaction is completed, perform reduced pressure concentration. Wash the concentrate successively with deionized water, acetone and ethanol to obtain a hyper-crosslinked porous polymer.

[0036] S4. Add 1 g of the hyper-crosslinked porous polymer to 20 mL of ethanol solvent, disperse evenly, then add 0.7 g of Pd / C catalyst for catalytic hydrogenation reduction reaction. After the reaction is completed, filter the solvent, and wash the obtained filter cake with deionized water and ethanol to obtain a hyper-crosslinked nitrogen-rich porous polymer. The reaction diagram for preparing the hyper-crosslinked nitrogen-rich porous polymer is as Figure 1 shown.

[0037] Perform infrared spectrum detection on the prepared hyper-crosslinked nitrogen-rich porous polymer. The infrared spectrum diagram of the hyper-crosslinked nitrogen-rich porous polymer is as Figure 2 shown, proving that the nitrogen-rich porous polymer has been prepared.

[0038] Example 2

[0039] The preparation method of the nitrogen-rich porous polymer provided in this example includes the following steps:

[0040] S1. Add 0.73 g of cyanuric chloride and 0.56 g of p-nitrophenol to 20 mL of acetone solvent under an ice bath, then add an aqueous solution of 10% sodium carbonate, stir and react for 2 h. After the reaction is completed, perform vacuum concentration. Wash the concentrate with deionized water and add acetone for recrystallization to obtain nitro-phenoxy dichloro-s-triazine.

[0041] S2. Add 3 g of nitro-phenoxy dichloro-s-triazine and 4.2 g of carbazole to 180 mL of tetrahydrofuran solution, then dropwise add a tetrahydrofuran solution containing 3.2 g of n-butyllithium under a nitrogen atmosphere, and reflux and react at 75 °C for 6 h. After the reaction is completed, perform vacuum concentration. Wash the concentrate successively with deionized water and n-hexane, and then add the precipitate to ethanol for recrystallization to obtain nitro-phenoxy dicarbazolyl s-triazine.

[0042] S3. Add 1 g of nitro-phenoxy dicarbazolyl s-triazine, 1 g of aluminum chloride and 0.52 g of dimethoxymethane to 80 mL of chloroform solvent, reflux and react at 75 °C for 30 h. After the reaction is completed, perform vacuum concentration. Wash the concentrate successively with deionized water, acetone and ethanol to obtain a hypercrosslinked porous polymer.

[0043] S4. Add 1 g of the hypercrosslinked porous polymer to 50 mL of ethanol solvent, disperse evenly, then add 0.12 g of Pd / C catalyst for catalytic hydrogenation reduction reaction. After the reaction is completed, filter the solvent, and wash the obtained filter cake with deionized water and ethanol to obtain a hypercrosslinked nitrogen-rich porous polymer. The reaction diagram for preparing the hypercrosslinked nitrogen-rich porous polymer is as Figure 1 shown.

[0044] Example 3

[0045] The preparation method of the nitrogen-rich porous polymer provided in this example includes the following steps:

[0046] S1. Add 0.73 g of cyanuric chloride and 0.56 g of p-nitrophenol to 30 mL of acetone solvent under an ice bath, then add an aqueous solution of 9% sodium carbonate, stir and react for 3 h. After the reaction is completed, perform vacuum concentration. Wash the concentrate with deionized water and add acetone for recrystallization to obtain nitro-phenoxy dichloro-s-triazine.

[0047] S2. Add 3 g of nitro-phenoxy dichloro-s-triazine and 4 g of carbazole to 200 mL of tetrahydrofuran solution, then dropwise add a tetrahydrofuran solution containing 2.3 g of n-butyllithium under a nitrogen atmosphere, and reflux and react at 60 °C for 10 h. After the reaction is completed, perform vacuum concentration. Wash the concentrate successively with deionized water and n-hexane, and then add the precipitate to ethanol for recrystallization to obtain nitro-phenoxy dicarbazolyl s-triazine.

[0048] S3. Add 1 g of nitro-phenoxy dicarbazolyl-s-triazine, 0.9 g of aluminum chloride, and 0.48 g of dimethoxymethane into 50 mL of chloroform solvent, reflux and react at 80 °C for 24 h. After the reaction is completed, perform vacuum concentration. Wash the concentrate with deionized water, acetone, and ethanol to obtain a hyper-crosslinked porous polymer.

[0049] S4. Add 1 g of the hyper-crosslinked porous polymer into 20 mL of ethanol solvent. After dispersing evenly, add 0.1 g of Pd / C catalyst and perform catalytic hydrogenation reduction reaction. After the reaction is completed, filter the solvent, and wash the obtained filter cake with deionized water and ethanol to obtain a hyper-crosslinked nitrogen-rich porous polymer. The reaction diagram for preparing the hyper-crosslinked nitrogen-rich porous polymer is as Figure 1 shown.

[0050] Comparative Example 1

[0051] The preparation method of the nitrogen-rich porous polymer provided in this comparative example includes the following steps:

[0052] S1. Add 0.73 g of cyanuric chloride and 0.56 g of p-nitrophenol into 20 mL of acetone solvent under ice bath, then add an aqueous solution of 8% sodium carbonate, stir and react for 2 h. After the reaction, perform vacuum concentration, wash with deionized water, and add acetone for recrystallization to obtain nitro-phenoxy dichloro-s-triazine.

[0053] S2. Add 3 g of nitro-phenoxy dichloro-s-triazine and 3.8 g of carbazole into 150 mL of tetrahydrofuran solution, then dropwise add a tetrahydrofuran solution containing 2.6 g of n-butyllithium under a nitrogen atmosphere, reflux and react at 60 °C for 12 h. After the reaction, perform vacuum concentration, wash successively with deionized water and n-hexane, and add the product to ethanol for recrystallization to obtain nitro-phenoxy dicarbazolyl-s-triazine.

[0054] S3. Add 1 g of nitro-phenoxy dicarbazolyl-s-triazine, 1 g of aluminum chloride, and 0.62 g of dimethoxymethane into 80 mL of chloroform solvent, reflux and react at 75 °C for 30 h. After the reaction, perform vacuum concentration, wash successively with deionized water, acetone, and ethanol to obtain a hyper-crosslinked porous polymer.

[0055] Experimental Example 1

[0056] (1) Use a high-throughput specific surface area and pore size analyzer to measure the specific surface areas of the hyper-crosslinked nitrogen-rich porous polymers prepared in Examples 1-3 and the hyper-crosslinked porous polymer prepared in Comparative Example 1. The measurement results are as Figure 3 shown.

[0057] (2) Methyl Orange Adsorption Test: Take 50 mg each of the hyper-crosslinked nitrogen-rich porous polymers prepared in Examples 1-3 and the hyper-crosslinked porous polymer prepared in Comparative Example 1, and add them separately to 100 mL of a methyl orange solution with a mass concentration C0 of 200 mg / L. Stir until adsorption equilibrium at pH 5 and 25 °C, and then determine the mass concentration C of methyl orange in the solution by ultraviolet-visible spectrophotometry. 平衡 , and calculate the equilibrium adsorption capacity q, q = (C0 - C1)V / m.

[0058] The specific surface areas and methyl orange adsorption capacity test results of the hyper-crosslinked nitrogen-rich porous polymers prepared in Examples 1-3 and the hyper-crosslinked porous polymer prepared in Comparative Example 1 are as Figure 3 shown. It can be seen from Figure 3 that: The specific surface areas of the hyper-crosslinked nitrogen-rich porous polymers prepared in Examples 1-3 of the present invention are all significantly better than that of Comparative Example 1; the mass concentration C of methyl orange in the solution 平衡 ; and the equilibrium adsorption capacity q are all significantly better than that of Comparative Example 1. It can be seen that the hyper-crosslinked nitrogen-rich porous polymer prepared by the preparation method of the present invention has a high adsorption capacity for dyes such as methyl orange and a good removal effect.

[0059] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0060] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A preparation method of a nitrogen-rich porous polymer, characterized in that, It includes the following steps: S1. Cyanuric chloride and p-nitrophenol with a molar ratio of 1:1 are added to organic solvent A under an ice bath, and then an 8-10% aqueous sodium carbonate solution is added. Stir and react for 1-3 h. After the reaction is completed, carry out vacuum concentration to obtain concentrate A; S2. Wash the concentrate A in S1 with deionized water and then add organic solvent A for recrystallization to obtain nitro-phenoxy dichloro-s-triazine. The structural formula of the nitro-phenoxy dichloro-s-triazine is: ; S3. The nitro-phenoxy dichlorotriazine and carbazole in S2 are added to a tetrahydrofuran solution, and then a tetrahydrofuran solution of n-butyllithium is added dropwise in a nitrogen atmosphere for reaction. After the reaction is completed, carry out vacuum concentration to obtain concentrate B; S4. After washing the concentrate B in S3 successively with deionized water and organic solvent B, a precipitate is obtained; adding the precipitate into organic solvent C for recrystallization to obtain nitro-phenoxydicarbazolyl-s-triazine; the structural formula of the nitro-phenoxydicarbazolyl-s-triazine is: ; S5: Aluminum chloride, dimethoxymethane and chloroform solvent are added to the nitro-phenoxy dicarbazolyl triazine in S4 for reaction. After the reaction is completed, carry out vacuum concentration to obtain concentrate C; S6. After successively washing the concentrate C in S5 with deionized water, organic solvent A, and organic solvent C, a hypercrosslinked porous polymer is obtained; the structural formula of the hypercrosslinked porous polymer is: ; S7. Add the hypercrosslinked porous polymer in S6 into organic solvent C. After uniform dispersion, add Pd / C catalyst for catalytic hydrogenation reduction reaction. After the reaction ends, filter. Wash the obtained filter cake with deionized water and organic solvent C to obtain a hypercrosslinked nitrogen-rich porous polymer. The structural formula of the hypercrosslinked nitrogen-rich porous polymer is: ; Application of the nitrogen-rich porous polymer in the adsorption and separation of methyl orange dye in wastewater treatment.

2. A method for preparing a nitrogen-rich porous polymer as described in claim 1, characterized in that, The organic solvent A is acetone, the organic solvent B is n-hexane, and the organic solvent C is ethanol.

3. A method for preparing a nitrogen-rich porous polymer as described in claim 1, characterized in that, The molar ratio of the nitro-phenoxy dichlorotriazine in S2 to the carbazole and n-butyllithium in S3 is 1:2 to 2.6:3.5 to 5.

4. The preparation method of a nitrogen-rich porous polymer according to claim 1, characterized in that: When the nitro-phenoxy dichlorotriazine and carbazole in S3 are added to a tetrahydrofuran solution and then a tetrahydrofuran solution of n-butyllithium is added dropwise in a nitrogen atmosphere for reaction, the reaction conditions are reflux at 60-75 °C for 6-12 h; the addition amount of the tetrahydrofuran solution is 150-200 mL.

5. The preparation method of a nitrogen-rich porous polymer according to claim 1, wherein: The molar ratio of the nitro-phenoxy dicarbazolyl triazine, aluminum chloride and dimethoxymethane in S5 is 1:3.8 to 4.5:3.5 to 5.

6. The preparation method of a nitrogen-rich porous polymer according to claim 1, characterized in that: When the nitro-phenoxy dicarbazolyl triazine, aluminum chloride, dimethoxymethane and chloroform solvent in S5 are reacted, the reaction conditions are reflux at 75-85 °C for 20-30 h; the addition amount of the chloroform solvent is 50-100 mL.

7. The preparation method of a nitrogen-rich porous polymer according to claim 1, wherein: The dosage of the Pd / C catalyst in S7 is 7-12% of the mass of the hypercrosslinked porous polymer.

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