CN101798384A - Poly[1,4-diiminophenyl-4-(difluoromethyl-carbonyl)benzoyl-1,4-diiminophenyl p-dibenzoyl] and synthetic method thereof - Google Patents

Abstract

The invention relates to a fluorine-containing polyarylamide-poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-benzoyl Acyl] and synthetic method thereof, the structural formula of this compound is: The present invention introduces fluorine atoms into the main chain of the polymer, not only utilizes the unique structure of the above-mentioned CF bond, but also utilizes the introduction of CF to appropriately reduce the crystallization performance of PPTA, increase its flexibility, and improve its solubility. Its original excellent performance is preserved.

Description

Poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-dibenzoyl] and its synthetic method

Technical field:

The invention relates to a fluorine-containing polyarylamide and a synthesis method thereof, in particular to a poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-bis Iminophenyl p-dibenzoyl] and its synthesis method.

Background technique:

Polyamides with aliphatic main chains are called nylons and have been widely used in various fields. However, due to the high content of amide groups in nylon, it leads to high water absorption, poor dimensional stability of products, low glass transition temperature, and insufficient heat resistance, etc., thus limiting its application range, and introducing aromatic rings into the main chain of polyamide molecules, Just can improve above-mentioned defective of nylon. Nylon synthesized from aromatic diamines and aromatic dibasic acids is called "fully aromatic nylon", which has the following characteristics: one is an amorphous polymer, but it can be crystallized at 340-360 ° C; two Embrittlement temperature -70°C, Vicat softening point 270°C, high temperature resistance, radiation resistance, corrosion resistance, wear resistance, and self-extinguishing properties; three, it can still maintain high electrical properties in a wet state, which is better than mica. The scratch resistance of the paint film is good. Based on the needs of space development and military use, especially the increasing demand for heat-resistant fibers, DuPont of the United States successfully developed fully aromatic polyamide in the 1970s and realized industrial production. Poly-p-phenylene terephthalamide (PPTA), a fiber-grade product of DuPont, is named "Kevlar" and is called "aramid-II" in my country.

很强的C-F键能(485kJ.mol-1)。通过对已经报道的文献研究，我们发现：现有的对聚芳酰胺(PPTA)含氟改性主要集中在高分子侧链上引入氟原子，这种改性由于氟原子不在高分子主链上，改善的效果不是很明显。In general, there is an inverse relationship between heat resistance and solubility, the higher the heat resistance, the worse the solubility. Due to its special structure, PPTA has poor solubility and can only be dissolved in concentrated sulfuric acid. At the same time, PPTA has poor processability and cannot be processed by conventional polymer materials. Considering the problems of PPTA, the modification of polyaramide PPTA has been paid special attention and attention. As a kind of polymer material, fluorine-containing polymers exhibit many special properties due to their many unique structures, such as: low polarizability of fluorine atoms, strong electronegativity, small The van der Waals radius of

Strong CF bond energy (485kJ.mol-1). Through the study of the reported literature, we found that: the existing fluorine-containing modification of polyarylamide (PPTA) mainly focuses on the introduction of fluorine atoms on the side chain of the polymer. , the effect of improvement is not obvious.

Invention content:

One of the objects of the present invention is to provide a new polymer poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-bis Benzoyl].

The second object of the present invention is to provide a synthesis method of the polymer.

For achieving the above object, the reaction mechanism that the inventive method adopts is:

According to above-mentioned reaction mechanism, the present invention adopts following technical scheme:

A kind of poly [1,4-diiminophenyl-4-(difluoromethylcarbonyl) benzoyl-1,4-diiminophenyl p-dibenzoyl], it is characterized in that the structure of this compound for:

Where n is a natural number of 650-800.

Chinese name: poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-dibenzoyl] English name: poly[1, 4-diiminopheny-4-(difluoromethyl carbonyl)benzoyl-1, 4-diiminophenyterephthaloyl acyl]

Viscosity average molecular weight: 450,000

Appearance: light yellow powder

Infrared spectrum (using Perkin-Elmer983G infrared spectrometer, liquid film method):

νmax (cm ^-1 ): 3313, 1646, 1545, 1514, 1406, 1318, 1261, 1106, 1017, 892, 859, 825.

Proton NMR spectrum (500MHz, DMSO) chemical shift (unit ppm): 10.95 (s, 1H, NH); 10.51 (s, 3H, NH); 8.13 (d, J=7.5Hz, 4H, ArH); 8.03 ( d, J=8.0Hz, 2H, ArH); 7.76(d, J=8.0Hz, 2H, ARH); 7.36(d, J=8.0Hz, 2H, ArH); 7.26(d, J=8.0Hz, 2H , ArH); 6.51 (t, 4H, J=8.5Hz, ArH). NMR fluorine spectrum (470MHz, DMSO) chemical shift (in ppm): 101.44 (singlet).

A method for synthesizing the above-mentioned poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-dibenzoyl], wherein It is characterized in that the method has the following steps:

a. Dissolve ethyl p-iodobenzoate, ethyl bromodifluoroacetate, and copper powder in dimethyl sulfoxide at a molar ratio of 1:1:1, react at 55°C for 5 to 10 hours, and dilute with water , and then extracted with ethyl acetate, the organic phase was taken, washed with saturated brine, dried over magnesium sulfate, and then separated and purified to obtain colorless and transparent liquid 4-(1,1-difluoro-2-formyl-2- Ethoxy) methyl benzoate, its structural formula is:

b. 4-(1,1-difluoro-2-formyl-2-ethoxy)methyl benzoate obtained in step a was hydrolyzed under reflux in sodium hydroxide solution for 8 hours and then acidified to obtain white powder 4 -(1,1-difluoro-2-carboxymethyl)benzoic acid, its structural formula is:

c. Acyl chloride the 4-(1,1-difluoro-2-carboxymethyl)benzoic acid obtained in step b in sulfur oxychloride to obtain 4-(1,1-difluoro-2-chloro-2 -formyl) benzoyl chloride, its structural formula is:

d. Using N,N-dimethylacetamide as solvent, carry out amidation reaction of 4-(1,1-difluoro-2-chloro-2-formyl)benzoyl chloride obtained in step c with p-phenylenediamine Obtain N-(4-aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide, whose structural formula is:

e. under an inert atmosphere, use N,N-dimethylacetamide as a solvent, and use _CaCl as a catalyst to prepare N-(4-aminophenyl)-4-(2-(4-aminoanilino) obtained in step d )-1,1-difluoro-2-formyl)benzamide and terephthaloyl chloride carry out polyamide reaction, obtain yellow-brown solid poly[1,4-diiminophenyl-4- (Difluoromethylcarbonyl)benzoyl-1,4-diiminophenyltere-dibenzoyl].

The specific method of the above-mentioned step b is: 0.1 mole of 4-(1,1-difluoro-2-carboxymethyl)benzoic acid obtained in step a is dissolved in a mixed solvent of 20 milliliters of acetone and 50 milliliters of water, and 2 grams of Sodium hydroxide, heated and refluxed for 4 to 8 hours, adjusted the pH of the system to 1 to 3 at the end of the reaction, extracted the system with ethyl acetate, removed the solvent and dried to obtain a white solid 4-(1,1-difluoro-2 -carboxymethyl)benzoic acid.

The specific method of the above-mentioned step c is: under an inert atmosphere, the product 4-(1,1-difluoro-2-carboxymethyl)benzoic acid and thionyl chloride are dissolved in a molar ratio of 1:4 under an inert atmosphere. In N,N-dimethylformamide, after heating to reflux for 6 to 10 hours, remove unreacted thionyl chloride to obtain yellow liquid 4-(1,1-difluoro-2-chloro-2-formyl) Benzoyl chloride.

The specific method of the above-mentioned step d is as follows: under an inert atmosphere and an ice-water bath, slowly add 4-(1,1-difluoro-2-chloro-2-formyl)benzoyl chloride obtained in step c to terephthalic acid In N, N-dimethylacetamide solution of amine, and pyridine is used as acid absorbent, the reaction is completed after 4 to 8 hours, and ethyl acetate is added to precipitate solid, and yellow-brown solid powder N-(4 -aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide; step c obtained 4-(1,1-difluoro-2- The molar ratio of chloro-2-formyl)benzoyl chloride to p-phenylenediamine is 1:3.

The specific method of the above-mentioned step e is: under an inert atmosphere and an ice-water bath, the N-(4-aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro- 2-formyl)benzamide is dissolved in N,N-dimethylacetamide, and calcium chloride and pyridine are added as a catalyst to absorb the acid produced during the reaction; slowly add terephthaloyl chloride dropwise under stirring N, N-dimethylacetamide solution, after 4 to 10 hours of reaction, the reaction system was poured into ethanol, and a yellow-brown solid precipitated out. After filtering, washing and drying, the solid product poly[1,4-diethylene Aminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl p-dibenzoyl]; step d gained N-(4-aminophenyl)-4-(2 The molar ratio of -(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide to terephthaloyl chloride is 1:1.

Due to the small radius of the fluorine atom and its high electronegativity, the bond energy of the C-F bond formed by it is much larger than the bond energy of the C-H bond, which obviously increases the stability of the organic fluorine compound. wear resistance and so on. The present invention introduces fluorine atoms into the main chain of the polymer, not only utilizing the unique structure of the above-mentioned C-F bond, but also utilizing the introduction of C-F to appropriately reduce the crystallization performance of PPTA, increase its flexibility, and improve its solubility. Its original excellent performance is preserved.

Description of drawings

Fig. 1 is a graph showing the relationship between pulp content and elongation at break of the fluorine-containing polyaramid pulp of the present invention.

Fig. 2 is a graph showing the relationship between pulp content and tensile strength of the fluorine-containing polyaramid pulp of the present invention.

Fig. 3 is a relation diagram of pulp content-yield strength of the fluorine-containing polyaramid pulp of the present invention.

Fig. 4 is a graph showing the relationship between pulp content and notched impact value of fluorine-containing polyaramid pulp according to the present invention.

Detailed ways:

Embodiment one: (1) add 0.276 grams of ethyl p-iodobenzoate, 0.202 grams of ethyl bromodifluoroacetate, 0.064 grams of copper powder, 10 milliliters of dimethylsulfoxide in a 50 milliliter round-bottomed flask, and the reaction temperature is After reacting at 55 degrees Celsius for 8 hours, the reactant was poured into 20 ml of water and extracted three times with ethyl acetate, the organic phase was taken, washed three times with saturated brine, dried with magnesium sulfate, and the obtained concentrated solution was separated by silica gel chromatography. The developer is a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 10:1, and the obtained colorless transparent liquid 4-(1,1-difluoro-2-formyl-2-ethoxy)methyl benzoate 0.204 g of ester, yield 75%. (2) Add 2 milliliters of acetone, 5 milliliters of water and 0.02 gram of sodium hydroxide to the reaction product of the previous step, heat and reflux for 6 hours, adjust the pH value of the system to 1 with dilute hydrochloric acid, extract the system with ethyl acetate, remove the solvent and dry to obtain 0.158 g of white solid 4-(1,1-difluoro-2-carboxymethyl)benzoic acid, the yield was 98%. (3) Add 5 milliliters of thionyl chloride and 10 milliliters of N,N-dimethylformamide to the product obtained in the previous step, and evaporate unreacted thionyl chloride after heating to reflux for 8 hours to obtain yellow liquid 4-(1 , 1-difluoro-2-chloro-2-formyl)benzoyl chloride, and the product was protected with nitrogen gas for use. (4) Add 0.8 grams of p-phenylenediamine (excessive), 10 milliliters of N, N-dimethylacetamide, 1 milliliter of pyridine into a 50 milliliter three-necked flask, and protect it with nitrogen gas. After the system is completely dissolved, use an ice-water bath Cooling, then slowly add 4-(1,1-difluoro-2-chloro-2-formyl) benzoyl chloride dropwise to the system, the reaction ends after 6 hours, and 10 mL of ethyl acetate, the system precipitated a solid, filtered and washed to obtain a yellow-brown solid powder N-(4-aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-methyl Acyl) benzamide 0.229 g, yield 79%. (5) Put 0.229 g of the upper reaction product in a 50 ml reaction tube, protect the system with nitrogen and stir with a self-made micromachine, add 10 ml of N, N-dimethylacetamide, 0.1 g of calcium chloride and 2 ml of pyridine, and place on ice Bath cooling, then take 0.117 grams of terephthaloyl chloride and dissolve it with 2 milliliters of N,N-dimethylacetamide and slowly add it dropwise to the system. After 6 hours of reaction, the reaction is terminated, and the reaction system is poured into 20 milliliters of ethanol, filtered, Wash and dry to obtain 0.30 g of yellow-brown solid product poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-dibenzoyl] , and the yield was 87%.

Embodiment two: (1) in the round bottom flask of 50 milliliters, add 2.760 grams of ethyl p-iodobenzoate, 2.020 grams of ethyl bromodifluoroacetate, 0.640 grams of copper powder, 20 milliliters of dimethyl sulfoxide, reaction temperature is After reacting at 55 degrees Celsius for 8 hours, the reactant was poured into 50 ml of water and extracted three times with ethyl acetate, the organic phase was taken, washed three times with saturated brine, dried with magnesium sulfate, and the obtained concentrated solution was separated by silica gel chromatography. The developer is a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 10:1, and the obtained colorless transparent liquid 4-(1,1-difluoro-2-formyl-2-ethoxy)methyl benzoate 2.05 g of ester, 75% yield. (2) Add 10 milliliters of acetone, 20 milliliters of water and 0.20 grams of sodium hydroxide to reflux for 6 hours, adjust the pH value of the system to 1 with dilute hydrochloric acid, extract the system with ethyl acetate, remove the solvent and dry to obtain The white solid product 4-(1,1-difluoro-2-carboxymethyl)benzoic acid was 1.59 g, and the yield was 98%. (3) Add 10 milliliters of thionyl chloride and 20 milliliters of N,N-dimethylformamide to the product obtained in the previous step, and evaporate unreacted thionyl chloride and solvent after heating to reflux for 8 hours to obtain a yellow liquid 4- (1,1-difluoro-2-chloro-2-formyl)benzoyl chloride, and the product was protected with nitrogen until use. (4) Add 8.0 grams of p-phenylenediamine (excessive), 50 milliliters of N, N-dimethylacetamide, and 5 milliliters of pyridine into a 100 milliliter three-necked flask, and protect it with nitrogen. After the system is completely dissolved, use an ice-water bath Cool, then slowly add a part of the acid chloride obtained by the reaction dropwise to the system, the reaction ends after 6 hours, the reaction system is poured into 100 ml of ethyl acetate, the system precipitates a solid, filters, washes, and dries to obtain a yellow-brown solid powder N-(4-aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide 2.30 g, yield 79%. (5) Add 2.3 g of the upper reaction product to a 150 ml three-necked flask, protect the system with nitrogen and stir mechanically, add 40 ml of N, N-dimethylacetamide, 0.5 g of calcium chloride and 5 ml of pyridine, and cool in an ice bath , then take 1.173 grams of terephthaloyl chloride and dissolve it with 5 milliliters of N, N-dimethylacetamide and slowly add it dropwise to the system. After 6 hours of reaction, the reaction is terminated. Add 100 milliliters of ethanol to the system, and filter to obtain a yellow-brown solid , washed and dried solid product poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-dibenzoyl] 3.01 grams, yield was 87%.

Embodiment three: (1) add 27.60 grams of ethyl p-iodobenzoate, 20.20 grams of ethyl bromodifluoroacetate, 6.40 grams of copper powder, 150 milliliters of dimethyl sulfoxide in the round bottom flask of 250 milliliters, reaction temperature is After reacting at 55 degrees Celsius for 8 hours, the reactant was poured into 400 ml of water and extracted three times with ethyl acetate, the organic phase was taken, washed three times with saturated brine, dried with magnesium sulfate, and the obtained concentrated solution was separated by silica gel chromatography. The developer is a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 10:1, and the obtained colorless transparent liquid 4-(1,1-difluoro-2-formyl-2-ethoxy)methyl benzoate 20.60 g of ester, yield 75%. (2) Add 30 milliliters of acetone, 70 milliliters of water and 2.0 grams of sodium hydroxide to reflux for 6 hours, adjust the pH value of the system to 1 with dilute hydrochloric acid, extract the system with ethyl acetate, remove the solvent and dry to obtain The white solid product 4-(1,1-difluoro-2-carboxymethyl)benzoic acid was 16.0 g, and the yield was 98%. (3) Add 50 milliliters of thionyl chloride and 80 milliliters of N,N-dimethylformamide to the product obtained in the previous step, and evaporate unreacted thionyl chloride and solvent after heating to reflux for 8 hours to obtain a yellow liquid 4- (1,1-difluoro-2-chloro-2-formyl)benzoyl chloride, and the product was protected with nitrogen until use. (4) Add 80 grams of p-phenylenediamine (excessive), 250 milliliters of N, N-dimethylacetamide, and 20 milliliters of pyridine into a 500 milliliter three-necked bottle, and protect it with nitrogen. After the system is completely dissolved, use an ice-water bath Cooling, then slowly add the acid chloride obtained by a part of the reaction dropwise in the system, the reaction ends after 6 hours, the system is poured into 500 ml of ethyl acetate, the system precipitates a solid, and is filtered and washed to obtain a yellow-brown solid powder N-(4 -Aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide 24.05 g, yield 79%. (5) Add 20.0 g of the upper reaction product to a 500 ml three-necked flask and protect the system with nitrogen and mechanically stir, add 200 ml of N, N-dimethylacetamide, 2 g of calcium chloride and 20 ml of pyridine, and cool in an ice bath , then take 10.20 grams of terephthaloyl chloride and dissolve it with 15 milliliters of N,N-dimethylacetamide and slowly add it dropwise to the system. After 6 hours of reaction, the reaction is completed, and 500 milliliters of ethanol is added to the system, filtered, washed and dried Obtain 26.3 grams of yellow-brown solid product poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-dibenzoyl], the yield was 87%.

Performance Testing:

Use the fluorine-containing polyaramid pulp synthesized by the present invention to carry out doping compound modification on nylon 6. For the convenience of comparison and reference, use fluorine-free PPTA pulp as a reference. The structural formula of PPTA without pulp is as follows:

The present invention mainly tests the elongation at break, tensile strength, yield strength, and notched impact value of the composite material after composite modification, and the test curves are shown in Fig. 1 , Fig. 2 , Fig. 3 and Fig. 4 .

It can be seen from Figure 1 that with the increase of pulp content, the elongation at break of the composite decreases continuously. This is mainly because the addition of pulp splits the continuity of the matrix, and the uniform deformation of the matrix after stretching is affected, and the surface of the pulp is rough and many branches are trapped in the matrix, forming physical cross-linking points, hindering the relative molecular chains of the matrix. Sliding allows the matrix to be broken at very low strains. At the same time, it can be seen that under the same content conditions, the elongation at break of fluorine-containing pulp is higher than that of non-fluorine-containing pulp and matrix composites. This is mainly due to the introduction of CF ₂ into the molecule of the fluorine-containing pulp, which reduces the rigidity of the molecular segment and enhances the flexibility. After forming a cross-link with the matrix, the molecular chain is more likely to stretch and stretch, so that the resistance to the sliding of the matrix molecules becomes smaller. .

It can be seen from Figure 2 that under the condition of low pulp content, the tensile strength decreases with the increase of pulp content. The reason is that the addition of pulp splits the continuity of the matrix. Under certain tensile conditions, the matrix The material will break prematurely. However, when the pulp content reaches a certain proportion, the tensile strength increases with the increase of the pulp content, which is mainly due to the good compatibility between the pulp and the matrix after the pulp content in the matrix increases. , at this time the pulp has a reinforcing effect on the matrix material. In addition, it can be seen from Figure 2 that under the same pulp content, the tensile strength of the fluorine-containing pulp is higher than that of the non-fluorine-containing pulp and matrix composite material, which is also due to the flexibility of the fluorine-containing molecular chain. The molecule is good, the molecule is easy to stretch and can bear greater stretching.

It can be seen from Figure 3 that the yield strength increases with the increase of pulp content. Nylon 6 material will undergo crystallographic orientation during stretching, and at the same time, it will be strengthened. After the pulp is added, when the composite material is stretched, not only the matrix nylon will undergo crystallization orientation, but also the polyaramid macromolecule will also undergo crystallization orientation. At this time, the pulp will strengthen the matrix material. In addition, it can be seen from Figure 3 that under the same pulp content, the yield strength of pulp without fluorine is higher than that of pulp with fluorine, mainly because the molecular chain segment of pulp without fluorine is more rigid. Crystalline orientation occurs more readily when the matrix material is stretched.

It can be seen from Figure 4 that as the pulp content increases, the notched impact value decreases, and its trend is similar to the elongation at break in Figure 1. This is mainly due to the decrease in the plasticity of the matrix after the pulp is added. Similarly, under the same pulp content, the notched impact value of fluorine-containing pulp is higher than that of non-fluorine pulp, which is also due to the high molecular flexibility of fluorine-containing pulp, which has less influence on the plasticity of the matrix material.

In summary, the fluorine-containing polyarylamide poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl-p-diphenyl Formyl] is an excellent material.

Claims (6)

1. A poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl)benzoyl-1,4-diiminophenyl p-dibenzoyl], characterized in that the compound The structure is:

Where n is an integer of 650-800. 2. a synthetic poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl) benzoyl-1,4-diiminophenyl-p-benzoyl toluene according to claim 1 The method of acyl] is characterized in that the method has the following steps: a. Dissolve methyl p-iodobenzoate, ethyl bromodifluoroacetate, and copper powder in dimethyl sulfoxide at a molar ratio of 1:1:1, react at 55°C for 4 to 8 hours, and dilute with water, Then extract with ethyl acetate, take the organic phase, wash with saturated brine, dry over magnesium sulfate, and then separate and purify to obtain colorless and transparent liquid 4-(1,1-difluoro-2-formyl-2-ethane Oxygen) methyl benzoate, its structural formula is:

b. Hydrolyze methyl 4-(1,1-difluoro-2-formyl-2-ethoxy)benzoate obtained in step a under alkaline conditions and then acidify and hydrolyze to obtain 4-(1 , 1-difluoro-2-carboxymethyl) benzoic acid, its structural formula is:

c. Acyl chloride the 4-(1,1-difluoro-2-carboxymethyl)benzoic acid obtained in step b in sulfur oxychloride to obtain 4-(1,1-difluoro-2-chloro-2 -formyl) benzoyl chloride its structural formula is: d. Using N,N-dimethylacetamide as solvent, carry out amidation reaction of 4-(1,1-difluoro-2-chloro-2-formyl)benzoyl chloride obtained in step c with p-phenylenediamine Obtain N-(4-aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide, whose structural formula is:

e. under an inert atmosphere, use N,N-dimethylacetamide as a solvent, and use _CaCl as a catalyst to prepare N-(4-aminophenyl)-4-(2-(4-aminoanilino) obtained in step d )-1,1-difluoro-2-formyl)benzamide and terephthaloyl chloride carry out polyamide reaction, obtain yellow-brown solid poly[1,4-diiminophenyl-4- (Difluoromethylcarbonyl)benzoyl-1,4-diiminophenyltere-dibenzoyl]. 3. The method according to claim 2, characterized in that the specific method of the step b is: the step a obtained 4-(1,1-difluoro-2-formyl-2-ethoxy)benzene Dissolve 0.1 mol of methyl formate in a mixed solvent of 20 milliliters of acetone and 50 milliliters of water, add 2 grams of sodium hydroxide, heat and reflux for 3 to 8 hours, and adjust the pH of the system to about 1 to 3 after the reaction is completed. The ester extraction system, solvent removal and drying afforded 4-(1,1-difluoro-2-carboxymethyl)benzoic acid as a white solid. 4. The method according to claim 2, characterized in that the specific method of step c is: under an inert atmosphere, the 4-(1,1-difluoro-2-carboxymethyl) obtained in step b Benzoic acid and thionyl chloride were dissolved in N,N-dimethylformamide at a molar ratio of 1:4, heated to reflux for 4 to 10 hours, and unreacted thionyl chloride and solvent were removed to obtain yellow liquid 4-( 1,1-difluoro-2-chloro-2-formyl)benzoyl chloride. 5. The method according to claim 2, characterized in that the specific method of the step d is: under an inert atmosphere and an ice-water bath, the obtained 4-(1,1-difluoro-2-chloro-2 -Formyl)benzoyl chloride is slowly added dropwise to the N,N-dimethylacetamide solution of p-phenylenediamine, and pyridine is used as the acid absorbent, reacted for 4 to 10 hours, and ethyl acetate is added to precipitate Solid, obtained yellow brown solid powder N-(4-aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide after filtering and washing; step c The molar ratio of the obtained 4-(1,1-difluoro-2-chloro-2-formyl)benzoyl chloride to p-phenylenediamine is 1:3. 6. The method according to claim 2, characterized in that the specific method of the described step e is: under an inert atmosphere and an ice-water bath, the N-(4-aminophenyl)-4-(2- (4-Aminoanilino)-1,1-difluoro-2-formyl)benzamide is dissolved in N,N-dimethylacetamide, and calcium chloride and pyridine are added as a catalyst to absorb the reaction process The acid produced in the solution; under stirring, slowly add the N, N-dimethylacetamide solution of terephthaloyl chloride dropwise, react for 4 to 7 hours, pour the reaction system into ethanol, and a yellow-brown solid precipitates out, after filtering and washing And dry back solid product poly[1,4-diiminophenyl-4-(difluoromethylcarbonyl) benzoyl-1,4-diiminophenyl p-dibenzoyl]; step d gained N The molar ratio of -(4-aminophenyl)-4-(2-(4-aminoanilino)-1,1-difluoro-2-formyl)benzamide to terephthaloyl chloride is: 1: 1.

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