阅读说明：本技术 一种含二氨基苯结构的活性二氟二苯砜单体及其制备方法 (Active difluoro diphenyl sulfone monomer containing diaminobenzene structure and preparation method thereof ) 是由 汪称意 蔡世举 陶正旺 钱佳锋 赵晓燕 李坚 任强 于 2020-12-25 设计创作，主要内容包括：本发明提供了一种含二氨基苯结构的活性二氟二苯砜单体及其制备方法,该活性二氟二苯砜单体为3,3′-二(3″-氨基苯基)-4,4′-二氟二苯砜,其制备方法为：先由3,3′-二溴-4,4′-二氟二苯砜和3-硝基苯硼酸通过Suzuki偶联反应得到含二硝基苯结构的二氟二苯砜中间体3,3′-二(3″-硝基苯基)-4,4′-二氟二苯砜,再通过水合肼将中间体中的硝基还原成氨基得到含二氨基苯结构的活性二氟二苯砜单体。该活性二氟二苯砜单体合成路线简便、产率高,具有良好的化学稳定性,可用于制备含胺基结构聚芳醚砜及其高性能离子交换膜材料,具有潜在应用价值。(The invention provides a diamino benzene structure-containing active difluoro diphenyl sulfone monomer and a preparation method thereof, wherein the active difluoro diphenyl sulfone monomer is 3,3 ' -di (3 ' -aminophenyl) -4,4 ' -difluoro diphenyl sulfone, and the preparation method comprises the following steps: firstly, carrying out Suzuki coupling reaction on 3,3 ' -dibromo-4, 4 ' -difluorodiphenyl sulfone and 3-nitrophenylboronic acid to obtain a difluorodiphenyl sulfone intermediate 3,3 ' -di (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone containing a dinitrobenzene structure, and then reducing nitro groups in the intermediate into amino groups through hydrazine hydrate to obtain an active difluorodiphenyl sulfone monomer containing a diaminobenzene structure. The active difluoro diphenyl sulfone monomer has simple and convenient synthesis route, high yield and good chemical stability, can be used for preparing the amino-containing polyarylether sulfone and the high-performance ion exchange membrane material thereof, and has potential application value.)

1. An active difluoro diphenyl sulfone monomer containing a diaminobenzene structure is characterized in that: the monomer is 3,3 ' -bis (3 ' -aminophenyl) -4,4 ' -difluorodiphenyl sulfone, and the structural formula of the monomer is as follows:

2. a process for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 1, characterized in that: the preparation method comprises the following steps:

(1) under the protection of nitrogen, respectively adding 3,3 ' -dibromo-4, 4 ' -difluorodiphenyl sulfone and 3-nitrophenylboronic acid in a certain molar ratio into a reaction vessel, further adding a catalyst and an organic solvent, stirring uniformly at room temperature, then adding an alkali solution and a cosolvent, continuing to react for 8-16 h under a reflux state, then evaporating toluene, and recrystallizing a crude product after suction filtration and drying to obtain an intermediate 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone;

(2) under the protection of nitrogen, adding the 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone prepared in the step (1) into a reaction vessel, further adding a solvent, a catalyst and a reducing agent, reacting for 4-10 h under a reflux state, ending the reaction, and obtaining an active difluorodiphenyl sulfone monomer containing a diamino structure through heat filtration, precipitation in water, filtration and drying: 3,3 '-bis (3 "-aminophenyl) -4, 4' -difluorodiphenyl sulfone.

3. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: in the step (1), the molar ratio of the added 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone to the added 3-nitrophenylboronic acid is 1: 2.0-2.5.

4. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: the catalyst in the step (1) is one of tetrakis (triphenylphosphine) palladium or palladium chloride (tricyclohexylphosphine tetrafluoroborate) or palladium acetate (tricyclohexylphosphine tetrafluoroborate), and the using amount of the catalyst is 0.03-0.06 time of the molar amount of the 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone.

5. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: the organic solvent in the step (1) is toluene, and the dosage of the organic solvent is 3-6 times of the mass sum of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone and 3-nitrophenylboronic acid.

6. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: the alkali solution in the step (1) is one of a sodium carbonate solution and a potassium carbonate solution, the concentration of the alkali solution is 2.0-3.0 mol/L, and the using amount of the alkali is 4-8 times of the molar amount of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone.

7. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: the cosolvent in the step (1) is ethylene glycol dimethyl ether, and the dosage of the cosolvent is 0.20-0.25 times of the mass of toluene.

8. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: the solvent in the step (2) is ethanol, and the dosage of the solvent is 5-10 times of the mass of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone.

9. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: the catalyst in the step (2) is a palladium-carbon catalyst, and the dosage of the palladium-carbon catalyst is 0.04-0.08 times of the mass of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone.

10. A method for preparing a diaminobenzene structure-containing active difluorodiphenyl sulfone monomer as claimed in claim 2, characterized in that: the reducing agent in the step (2) is 50% hydrazine hydrate, and the using amount of the reducing agent is 4-8 times of the molar amount of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone.

Technical Field

The invention relates to an active difluoro diphenyl sulfone monomer, in particular to an active difluoro diphenyl sulfone monomer containing a diaminobenzene structure and a preparation method thereof, belonging to the field of preparation of aromatic difluoro monomers.

Background

The aromatic polymer anion exchange membrane is an important functional polymer material and can be applied to high-tech fields such as fuel cells, vanadium flow batteries, electrodialysis and the like. However, the ion conductivity of the aromatic polymer anion exchange membrane material is generally low, the alkali-resistant stability is also poor, and a large gap is still formed between the ionic conductivity and the alkali-resistant stability and the ideal requirements of a fuel cell and a vanadium flow battery. In recent years, researches show that by introducing flexible side chain cations into an aromatic polymer structure, the movement flexibility of cationic groups can be improved, and an anion membrane material is promoted to form an effective ion transmission channel, so that the ion conductivity of the membrane material is effectively improved. Meanwhile, due to the introduction of a flexible side chain structure, the charge induction effect of the cationic group and the polymer main chain is reduced, and the alkali resistance stability of the membrane material can be improved. The aromatic polymer anion exchange membrane material containing the flexible cation side chain structure is mainly prepared by polymer grafting reaction, and the grafting reaction requires a polymer matrix structure containing a reactive group.

Amino-type polymers are an important group of graftable reactive matrix Materials, which have been used in the preparation of polymer anion exchange Membrane Materials containing flexible side chain structures (Science China Materials, 2020, 63(4), 533-. The polymer needs an active bifunctional structural monomer containing an amino structure, but currently, commercially available active monomers containing the amino structure only comprise a few bisphenol monomers such as 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 3 '-diamino-4, 4' -dihydroxybiphenyl and 2, 2-bis (4-hydroxy-3-aminophenyl) propane, but the phenol monomers are poor in stability and easy to oxidize.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to solve the problems and provides an active difluoro diphenyl sulfone monomer containing a diaminobenzene structure and a preparation method thereof, wherein 3,3 '-dibromo-4, 4' -difluoro diphenyl sulfone and 3-nitrophenylboronic acid are used as initial raw materials, and the active difluoro diphenyl sulfone monomer containing the diaminobenzene structure is obtained through two-step reaction of Suzuki coupling and redox.

In order to solve the problems, the invention is realized by the following technical scheme:

the invention provides an active difluoro diphenyl sulfone monomer containing a diaminobenzene structure, which has a structural formula as follows:

the melting point of the active difluoro diphenyl sulfone monomer containing the diaminobenzene structure is 57-59 ℃, and the active difluoro diphenyl sulfone monomer is light cyan powder at normal temperature.

The invention also provides a preparation method of the active difluoro diphenyl sulfone monomer containing the diaminobenzene structure, which comprises the following specific steps:

(1) under the protection of nitrogen, respectively adding 3,3 ' -dibromo-4, 4 ' -difluorodiphenyl sulfone and 3-nitrophenylboronic acid in a certain molar ratio into a three-neck flask, further adding a catalyst and an organic solvent, stirring uniformly at room temperature, then adding an alkali solution and a cosolvent, continuously reacting for 8-16 h under a reflux state, then evaporating toluene, carrying out suction filtration and drying on a crude product, and then recrystallizing to obtain an intermediate 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone, wherein the structural formula is as follows:

(2) under the protection of nitrogen, adding the 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone prepared in the step (1) into a three-neck flask, further adding a solvent, a catalyst and a reducing agent, reacting for 4-10 h under a reflux state, ending the reaction, and obtaining an active difluorodiphenyl sulfone monomer containing a diamino structure through heat filtration, precipitation in water, filtration and drying: 3,3 '-bis (3 "-aminophenyl) -4, 4' -difluorodiphenyl sulfone.

In the step (1), the molar ratio of the 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone to the 3-nitrophenylboronic acid is 1: 2.0-2.5;

according to the preparation method, the catalyst in the step (1) is one of tetrakis (triphenylphosphine) palladium, palladium chloride (tricyclohexylphosphine tetrafluoroborate) or palladium acetate (tricyclohexylphosphine tetrafluoroborate), and the using amount of the catalyst is 0.03-0.06 time of the molar amount of the 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone.

In the preparation method, the organic solvent in the step (1) is toluene, and the dosage of the organic solvent is 3-6 times of the mass sum of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone and 3-nitrophenylboronic acid.

In the preparation method, the alkali solution in the step (1) is one of a sodium carbonate solution and a potassium carbonate solution, the concentration of the alkali solution is 2.0-3.0 mol/L, and the using amount of the alkali is 4-8 times of the molar weight of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone.

In the preparation method, the cosolvent in the step (1) is ethylene glycol dimethyl ether, and the dosage of the cosolvent is 0.20-0.25 time of the mass of toluene.

The solvent in the step (2) of the preparation method is ethanol, and the dosage of the solvent is 5-10 times of the mass of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone.

The catalyst in the step (2) of the preparation method is a palladium-carbon catalyst, and the dosage of the catalyst is 0.04-0.08 times of the mass of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone.

According to the preparation method, the reducing agent in the step (2) is 50% hydrazine hydrate, and the using amount of the reducing agent is 4-8 times of the molar amount of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone.

The specific synthetic route of the active difluoro diphenyl sulfone monomer containing the diaminobenzene structure is as follows:

the invention has the beneficial effects that:

(1) the active difluoro diphenyl sulfone monomer containing the diaminobenzene structure prepared by the invention has the advantages of simple synthetic route, high yield and good chemical stability.

(2) The active difluoro diphenyl sulfone monomer containing the diaminobenzene structure can be used for preparing the polyarylether sulfone containing the amino structure and the anion membrane material thereof, and has potential application value.

Drawings

FIG. 1 is a 1H NMR spectrum of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone in example 1;

FIG. 2 is a drawing showing the preparation of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone of example 1¹H NMR spectrum;

FIG. 3 is a drawing showing the preparation of 3,3 ' -bis (3 ' -aminophenyl) -4,4 ' -difluorodiphenyl sulfone in example 1¹H NMR spectrum;

FIG. 4 is a drawing showing the preparation of 3,3 ' -bis (3 ' -aminophenyl) -4,4 ' -difluorodiphenyl sulfone in example 1¹³A C NMR spectrum;

FIG. 5 is an FTIR spectrum of 3,3 '-bis (3 "-aminophenyl) -4, 4' -difluorodiphenyl sulfone, example 1.

Detailed Description

Preferred embodiments of the present invention will be described in more detail with reference to specific examples.

The following are the raw materials and drugs used in the examples:

4, 4' -difluorodiphenyl sulfone: purchased from growth reagents, purity: 98.0 percent

N-bromosuccinimide: purchased from aladdin, AR, 99.00%

Sulfuric acid: purchased from national medicine group chemical reagent limited, analytically pure, content: 95.0 to 98.0 percent

3-nitrophenylboronic acid: purchased from sukharo chemistry, purity: not less than 98.0 percent

Tetrakis (triphenylphosphine) palladium: purchased from Shanxi Kaida chemical industry, Ltd, analytically pure, palladium content: not less than 9.2 percent

Toluene: purchased from national pharmaceutical group chemical agents ltd, content (GC): not less than 99.5 percent

Na2CO 3: purchased from national pharmaceutical group chemical agents ltd, content: not less than 99.8 percent

K2CO 3: purchased from shanghai Linfeng Chemicals, ltd, content: not less than 99.0 percent

Ethylene glycol dimethyl ether: purchased from aladdin, AR, 99.5% (GC)

Ethanol: purchased from national pharmaceutical group chemical agents ltd, content (GC): not less than 99.7 percent

Pd/C: purchased from shanxi openda chemical llc, with palladium content: 5.0 percent

N, N-dimethylacetamide: purchased from shanghai Linfeng Chemicals, ltd, content: not less than 98.0 percent

Hydrazine hydrate: purchased from national medicine group chemical reagent limited, analytically pure, content: not less than 50.0%

Example 1

(1) Synthesis of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone:

the 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone used in this example was prepared by itself, and the preparation steps were: 25.43g (0.1mol) of 4, 4' -difluorodiphenyl sulfone monomer and 200mL of concentrated sulfuric acid were charged into a 500mL three-necked flask equipped with a nitrogen inlet/outlet and an electric stirrer, and dissolved by stirring at room temperature until homogeneous. Adding 39.16g (0.22mol) of N-bromosuccinimide into a flask in three times (with an interval of 15min each time) and violently stirring until the N-bromosuccinimide is completely dissolved, after reacting for 10 hours, pouring milky white reaction liquid containing a large amount of foams into 1500mL of ice water while stirring, cooling to room temperature, performing suction filtration, washing the obtained white solid to be neutral by using a large amount of deionized water, drying, and recrystallizing by using toluene to obtain 35.20g of a white granular product with the yield of 85%; 1H NMR (DMSO-d6,400MHz) was as shown in FIG. 1.

(2) Synthesis of 3,3 '-bis (3 "-nitrophenyl) -4, 4' -difluorodiphenyl sulfone:

in a 500mL three-necked flask equipped with a reflux condenser, a nitrogen inlet/outlet port and an electric stirrer were placed 12.36g (0.03mol) of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone, 10.52g (0.063mol) of 3-nitrophenylboronic acid, 1.38g (0.0012mol) of tetrakis (triphenylphosphine) palladium and 95mL of toluene in this order, and they were dissolved by stirring at room temperature, followed by adding 25.44g (0.24mol) of Na to the pale yellow reaction solution₂CO₃And 100mL of water, finally adding 20mL of ethylene glycol dimethyl ether, heating to 105 ℃, keeping the solution black, and continuing to react for 10 hours. Heating the reaction temperature to 135 ℃ to evaporate toluene, cooling to room temperature, filtering, washing and drying to obtain a black solid primary product, dissolving and filtering the black solid primary product with N, N-dimethylacetamide, precipitating the filtrate in water, and performing column chromatography, reduced pressure concentration and drying on the precipitate to obtain 11.52g of a white product with a yield of 77%;¹H NMR(DMSO-d₆400MHz) as shown in figure 2.

(3) Synthesis of 3,3 '-bis (3 "-aminophenyl) -4, 4' -difluorodiphenyl sulfone:

sequentially adding 10.00g (0.02mol) of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone, 0.40g (4% of monomer mass) of Pd/C and 120mL of ethanol into a 250mL three-neck flask provided with a reflux condenser tube, a nitrogen inlet and a nitrogen outlet and an electric stirrer, heating to 95 ℃ and stirring to obtain a gray black turbid liquid, slowly dropwise adding 4.0mL (0.08mol) of hydrazine hydrate for 1 hour, continuously reacting for 8 hours, filtering a bright black reaction liquid while hot to obtain a light cyan transparent solution, cooling to room temperature, settling in deionized water, filtering, washing and drying to obtain 6.25g of a light cyan product, wherein the yield is 71%;¹H NMR(DMSO-d₆400MHz) as shown in fig. 3;¹³C NMR(DMSO-d₆400MHz) as shown in fig. 4; FTIR is shown in FIG. 5.

Example 2

(1) Synthesis of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone:

the 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone used in this example was prepared by itself, and the preparation steps were: 25.43g (0.1mol) of 4, 4' -difluorodiphenyl sulfone monomer and 180mL of concentrated sulfuric acid were charged into a 500mL three-necked flask equipped with a nitrogen inlet/outlet and an electric stirrer, and dissolved by stirring at room temperature until homogeneous. And then 39.16g (0.22mol) of N-bromosuccinimide is added into a flask in three times (with an interval of 15min each time) and is vigorously stirred until the N-bromosuccinimide is completely dissolved, after 10 hours of reaction, milky white reaction liquid containing a large amount of foams is poured into 1500mL of ice water while being stirred, the ice water is cooled to room temperature and is filtered, the obtained white solid is washed to be neutral by a large amount of deionized water, and is recrystallized by toluene after being dried, 33.75g of white granular product is obtained, and the yield is 82%.

(2) Synthesis of 3,3 '-bis (3 "-nitrophenyl) -4, 4' -difluorodiphenyl sulfone:

in a 500mL three-necked flask equipped with a reflux condenser, a nitrogen inlet/outlet port and an electric stirrer were placed 12.36g (0.03mol) of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone, 10.52g (0.063mol) of 3-nitrophenylboronic acid, 1.73g (0.0015mol) of tetrakis (triphenylphosphine) palladium and 100mL of toluene in this order, and they were dissolved by stirring at room temperature, followed by adding 33.17g (0.24mol) of K to the pale yellow reaction solution₂CO₃And 90mL of water, finally adding 20mL of ethylene glycol dimethyl ether, heating to 105 ℃, keeping the solution black, and continuing to react for 12 hours. Heating the reaction temperature to 135 ℃ to evaporate toluene, cooling to room temperature, filtering, washing and drying to obtain a black solid primary product, dissolving the black solid primary product with N, N-dimethylacetamide, filtering, precipitating the filtrate in water, and performing column chromatography, reduced pressure concentration and drying on the precipitate to obtain a white product 12.31g, wherein the yield is 82%.

(3) Synthesis of 3,3 '-bis (3 "-aminophenyl) -4, 4' -difluorodiphenyl sulfone:

10.00g (0.02mol) of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone, 0.60g (6% of the monomer mass) of Pd/C and 110mL of ethanol are sequentially added into a 250mL three-neck flask provided with a reflux condenser tube, a nitrogen inlet and a nitrogen outlet and an electric stirrer, the temperature is raised to 95 ℃ and the mixture is stirred to obtain gray black turbid liquid, at the moment, 6.0mL (0.12mol) of hydrazine hydrate is slowly dripped for 1h, then the reaction is continued for 10h, the bright black reaction liquid is filtered while hot to obtain light cyan transparent solution, and after the solution is cooled to room temperature, the solution is settled in deionized water, filtered, washed and dried to obtain 6.50g of light cyan white product, and the yield is 74%.

Example 3

(1) Synthesis of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone:

the 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone used in this example was prepared by itself, and the preparation steps were: 25.43g (0.1mol) of 4, 4' -difluorodiphenyl sulfone monomer and 160mL of concentrated sulfuric acid were charged into a 500mL three-necked flask equipped with a nitrogen inlet/outlet and an electric stirrer, and dissolved by stirring at room temperature until they became homogeneous. Then, 37.38g (0.21mol) of N-bromosuccinimide is added into a flask in three times (with an interval of 15min each time) and is vigorously stirred until the N-bromosuccinimide is completely dissolved, after 10 hours of reaction, milky white reaction liquid containing a large amount of foams is poured into 1500mL of ice water while being stirred, after cooling to room temperature, suction filtration is carried out, the obtained white solid is washed to be neutral by a large amount of deionized water, and after drying, recrystallization is carried out by toluene, 34.50g of white granular product is obtained, and the yield is 84%.

(2) Synthesis of 3,3 '-bis (3 "-nitrophenyl) -4, 4' -difluorodiphenyl sulfone:

in a 500mL three-necked flask equipped with a reflux condenser, a nitrogen inlet/outlet port and an electric stirrer were placed 12.36g (0.03mol) of 3,3 '-dibromo-4, 4' -difluorodiphenyl sulfone, 10.52g (0.063mol) of 3-nitrophenylboronic acid, 2.08g (0.0018mol) of tetrakis (triphenylphosphine) palladium and 105mL of toluene in this order, and the mixture was dissolved by stirring at room temperature, followed by adding 24.88g (0.18mol) of K to the pale yellow reaction solution₂CO₃And 70mL of water, finally adding 25mL of ethylene glycol dimethyl ether, heating to 105 ℃, and continuing to react for 16 hours, wherein the solution is black. Heating the reaction temperature to 135 ℃ to evaporate toluene, cooling to room temperature, filtering, washing with water and drying to obtain a black solid crude product, dissolving the black solid crude product with N, N-dimethylacetamide, filtering, precipitating the filtrate in water, drying the precipitate, passing through a column, concentrating under reduced pressure and drying to obtain a white product 11.2g, wherein the yield is 75%.

(3) Synthesis of 3,3 '-bis (3 "-aminophenyl) -4, 4' -difluorodiphenyl sulfone:

10.00g (0.02mol) of 3,3 ' -bis (3 ' -nitrophenyl) -4,4 ' -difluorodiphenyl sulfone, 0.80g (8% of the monomer mass) of Pd/C and 100mL of ethanol are sequentially added into a 250mL three-neck flask provided with a reflux condenser tube, a nitrogen inlet and a nitrogen outlet and an electric stirrer, the temperature is raised to 95 ℃ and the mixture is stirred to obtain gray black turbid liquid, at the moment, 8mL (0.16mol) of hydrazine hydrate is slowly dripped for 1.5h, then the reaction is continued for 9h, the bright black reaction liquid is filtered while hot to obtain light cyan transparent solution, and after the solution is cooled to room temperature, the solution is settled in deionized water, filtered, washed and dried to obtain 6.85g of light cyan white product, and the yield is 78%.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and technical principles of the described embodiments, and such modifications and variations should also be considered as within the scope of the present invention.