An amide-containing aromatic diamine, a polyimide, its preparation method and application

Abstract

An amide-containing aromatic diamine has the following structural formula: where Ar is a group with an aromatic ring structure. The preparation method includes the following steps: (1) mixing and reacting components including aromatic diamine, p-nitrobenzoic acid, alkyl phosphoric anhydride and polar aprotic organic solvent; (2) adding carboxylic acid and halogen-free quaternary ammonium salt to the product obtained in step (1) to obtain a mixed solution, which is placed in the cathode cell of an H-type electrolytic cell; the anode cell and the cathode cell are separated by a Nafion membrane; adding the same polar aprotic organic solvent and halogen-free organic electrolyte as the cathode cell to the anode cell of the H-type electrolytic cell, and adding a metal ion-free reducing agent; and conducting the reaction by electrolysis; (3) purifying the cathode reaction solution obtained in step (2) by post-treatment to obtain the amide-containing aromatic diamine. The yield, purity and whiteness of the amide-containing aromatic diamine are higher.

Description

Technical Field

[0001] This invention relates to the field of functional materials, and more specifically, to an amide-containing aromatic diamine, a polyimide, its preparation method, and its application. Background Technology

[0002] Polyimide is a polymer with excellent comprehensive properties. Its main chain contains an imide ring structure, which not only has excellent heat resistance, low temperature resistance, self-lubrication, and flame retardancy, but also has very good flexibility, strength and low dielectric properties. It can be used in various forms such as films, powders, fibers, foam materials, hybrid materials and adhesives, and is widely used in aerospace, defense industry, microelectronics, solar cells, high temperature filtration, communications, OLED and other fields.

[0003] Aromatic ring-coupled bis(4-aminobenzamide) derivatives have been proven to be important high-performance polyimide monomers (Reactive and Functional Polymers, 2019, 141, 155–164). Polyimides synthesized by the condensation polymerization of these diamine monomers with dianhydrides typically exhibit excellent light transmittance, superior mechanical strength, ultra-low thermal expansion, low dielectric constant, and good flexibility (Chinese invention patents CN104114532A, CN112375010A, CN112079743A). Polyimides synthesized from these diamine monomers show promising application prospects in fields such as mobile phone screens, 5G communications, national defense, and aerospace. However, current research on various types of amide-containing aromatic diamines as polyimide monomers remains very limited, and more novel amide-containing aromatic diamine monomers need to be developed to explore high-performance polyimide polymer materials. In terms of preparation methods, current methods for synthesizing these amide-containing aromatic amides typically involve a two-step reaction: an amidation reaction of an aromatic diamine with p-nitrobenzoyl chloride, followed by the reduction of the nitro group to an amino group. The first step generates a large amount of triethylamine hydrochloride as a byproduct, placing significant pressure on wastewater treatment in industrial production. Furthermore, the presence of chloride ions can easily lead to excessive chloride content in the final product. The second step generally uses a palladium / hydrogen reduction system. Palladium catalysts are not only expensive but also prone to introducing other metal ions; while the use of hydrogen poses safety risks. Summary of the Invention

[0004] In order to solve the technical problems existing in the prior art, the present invention provides an amide-containing aromatic diamine, a polyimide, a preparation method thereof, and its application.

[0005] Existing technologies primarily involve first converting p-nitrobenzoic acid to p-nitrobenzoyl chloride, then reacting it with an aromatic diamine via an amidation reaction, followed by catalytic hydrogenation to reduce the nitro group. This invention, however, directly uses p-nitrobenzoic acid as a raw material, reacting it directly with the aromatic diamine under the action of alkyl phosphoric anhydride. This reduces the number of reaction steps, saves costs, and lowers the process risk by eliminating the need for reagents such as p-nitrobenzoyl chloride or thionyl chloride. It also avoids the introduction of chloride ions.

[0006] In addition, this invention utilizes electrochemical conditions to reduce nitro groups to amino groups, and achieves the first-step amidation reaction without separation and purification, allowing the second-step reduction reaction to proceed directly. Compared with traditional catalytic hydrogenation methods or chemical reagent reduction methods, this is greener, more environmentally friendly, and safer. It avoids the use of high-pressure hydrogen and expensive palladium catalysts, saving resources and reducing purification steps, making the reaction more efficient.

[0007] This invention constructs a novel electrochemical reduction system for nitro compounds. It utilizes a strongly polar solvent as the solvent for the nitro compound, a halogen-free quaternary ammonium salt or a halogen-free ionic liquid as the electrolyte, an organic acid as the cathode for rapid hydrogen proton donation, and the same polar aprotic organic solvent and organic electrolyte as the anode. Hydrazine hydrate is used as the anode sacrificial agent, and an H-type electrolytic cell design is employed. A stable Pt electrode is used at the anode, and a carbon electrode at the cathode. This system enables the rapid reduction of nitro compounds that are poorly soluble in water and weakly polar solvents. No halogens or metal ions are involved in the entire reaction process, and the post-processing also avoids their involvement. This ensures that the halide and metal ion content of the obtained product easily meets electronic grade requirements.

[0008] One objective of this invention is to provide an amide-containing aromatic diamine with the following structural formula:

[0009]

[0010] Wherein, Ar is a group with an aromatic ring structure; preferably, Ar is one of the following structures:

[0011]

[0012] In a preferred embodiment of the present invention,

[0013] The amide-containing aromatic diamine is prepared by reacting components including aromatic diamine, p-nitrobenzoic acid, alkyl phosphoric anhydride, polar aprotic organic solvent, carboxylic acid, halogen-free organic electrolyte, metal ion-free reducing agent, inorganic base and pulping solvent.

[0014] In a preferred embodiment of the present invention,

[0015] The aromatic diamine is one of the following compounds.

[0016] And / or,

[0017] The alkyl phosphoric anhydride is at least one selected from propyl phosphoric anhydride, butyl phosphoric anhydride, and 1-ethyl cyclic phosphoric anhydride; and / or,

[0018] The polar aprotic organic solvent is at least one selected from dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; and / or

[0019] The carboxylic acid is at least one of acetic acid, propionic acid, butyric acid, and benzoic acid, used to rapidly provide the hydrogen protons required for the reduction of the nitro group to the amino group in the reaction; and / or,

[0020] The halogen-free organic electrolyte is at least one of a halogen-free quaternary ammonium salt, N-butylpyridine methanesulfonate, and N-hexyl-3-methylpyridine methanesulfonate, and its role in the reaction is to conduct electricity, without participating in the chemical reaction; the halogen-free quaternary ammonium salt is preferably at least one of tetrabutylammonium acetate, tetrabutylammonium formate, tetrabutylammonium sulfate, tetrabutylammonium hydrogen sulfate, tetrabutylammonium phosphate, tetrabutylammonium methanesulfonate, tetramethylammonium phosphate, tetramethylammonium sulfate, tetramethylammonium hydrogen sulfate, tetramethylammonium acetate, tetramethylammonium formate, tetramethylammonium methanesulfonate, tetraethylammonium acetate, tetraethylammonium formate, tetraethylammonium phosphate, tetraethylammonium sulfate, tetraethylammonium hydrogen sulfate, tetraethylammonium methanesulfonate, benzyltrimethylammonium acetate, benzyltrimethylammonium formate, benzyltrimethylammonium methanesulfonate, benzyltrimethylammonium phosphate, benzyltrimethylammonium sulfate, benzyltrimethylammonium hydrogen sulfate, and tetrapropylammonium hydrogen sulfate; and / or,

[0021] The metal-ion-free reducing agent is hydrazine hydrate, used as an anode sacrificial agent. It loses electrons at the anode and transforms into nitrogen gas, thus reducing the redox potential difference; and / or,

[0022] The inorganic base is at least one of ammonium carbonate and ammonia water; the concentration of the ammonia water is preferably 1-10 wt%; the function of the inorganic base is to cause unreacted p-nitrobenzoic acid to form a salt, which is then removed by washing with water. The advantage of using ammonium carbonate is that it does not introduce monovalent metal ions; and / or,

[0023] The solvent used for pulping is at least one of methanol, ethanol, ethyl acetate, and methyl tert-butyl ether.

[0024] A second objective of this invention is to provide a method for preparing an amide-containing aromatic diamine, comprising the following steps:

[0025] (1) Mix and react the components including aromatic diamine, p-nitrobenzoic acid, alkyl phosphoric anhydride and polar aprotic organic solvent;

[0026] (2) Add carboxylic acid and halogen-free organic electrolyte to the product obtained in step (1) to obtain a mixed solution, and place it in the cathode cell of an H-type electrolytic cell; the anode cell and the cathode cell are separated by a Nafion membrane; add the same polar aprotic organic solvent and halogen-free organic electrolyte as the cathode cell to the anode cell of the H-type electrolytic cell, and add a metal ion-free reducing agent, and then pass electricity to carry out the reaction;

[0027] (3) The cathodic reaction solution obtained in step (2) is purified by post-treatment to obtain the amide-containing aromatic diamine;

[0028] Preferably, the preparation method is used to prepare the amide-containing aromatic diamine according to any one of claims 1 to 3.

[0029] The reaction route is as follows:

[0030]

[0031] Where Ar is an aromatic ring and AXP is an alkyl phosphoric anhydride.

[0032] In a preferred embodiment of the present invention,

[0033] Step (1),

[0034] The molar ratio of the aromatic diamine, p-nitrobenzoic acid, and propylphosphine is 1:(2-4):(2.1-5), preferably 1:(2-2.1):(2.1-3); and / or,

[0035] The amount of the polar aprotic organic solvent added is 5 to 100 times the mass of the aromatic diamine, preferably 10 to 50 times; and / or,

[0036] The reaction is stirred at room temperature for 3–8 hours.

[0037] In a preferred embodiment of the present invention,

[0038] Step (2),

[0039] The amount of carboxylic acid added to the cathode cell is 0.5 to 8 times the mass of the aromatic diamine, preferably 1 to 5 times; and / or,

[0040] The amount of halogen-free organic electrolyte added to the cathode cell is 0.5 to 8 times the mass of the aromatic diamine, preferably 1 to 5 times; and / or,

[0041] The amounts of polar aprotic organic solvent and halogen-free organic electrolyte added to the anolyte are the same as those added to the cathode; and / or,

[0042] When the metal ion-free reducing agent is hydrazine hydrate, the effective content of hydrazine hydrate in the hydrazine hydrate is 40-69 wt%, and the amount of hydrazine hydrate added to the anode tank is 1-8 times the mass of the aromatic diamine, preferably 2-5 times; and / or,

[0043] The cathode uses metallic Pt as the electrode material; and / or,

[0044] The anode uses a carbon rod as the electrode material; and / or,

[0045] Apply direct current with a voltage of 0.75–1.1V; and / or,

[0046] The reaction is carried out under stirring; and / or,

[0047] The reaction temperature is 20–45°C; and / or,

[0048] The reaction time is 2 to 48 hours, preferably 6 to 24 hours.

[0049] In a preferred embodiment of the present invention,

[0050] Step (3),

[0051] The post-processing includes precipitation, filtration, and drying; preferably, the post-processing involves adding water to the cathodic reaction solution after the reaction to precipitate a solid, filtration to obtain a filter cake, dispersing it in an ammonium carbonate solution, mixing, filtration, adding water, mixing, filtration, adding methanol, mixing, filtration, and drying to obtain the amide-containing aromatic diamine.

[0052] More preferably,

[0053] Distilled water is added to the cathode reaction solution after the reaction in step (2), and after standing for 20-40 minutes, it is filtered to obtain filter cake A; more preferably, the amount of distilled water added is 4-10 times the total mass of the reaction solution in the cathode cell; and / or,

[0054] Filter cake A is dispersed in an ammonium carbonate solution, pulped at room temperature for 4–6 hours, and then filtered to obtain filter cake B; more preferably, the concentration of the ammonium carbonate solution is 5–20 wt%; and / or, the mass of the ammonium carbonate solution added is 5–50 times the mass of the aromatic diamine raw material; and / or,

[0055] Add filter cake B to distilled water and slurry at room temperature for 4–6 hours, then filter to obtain filter cake C; more preferably, the mass of distilled water added is 4–30 times the mass of the aromatic diamine raw material; and / or,

[0056] Filter cake C is dried to obtain a crude product containing amide-based aromatic diamine; the preferred drying temperature is 50–60°C; and / or,

[0057] The crude aromatic diamine containing amide groups is added to methanol, slurried at 50-60°C for 4-8 hours, cooled to room temperature, allowed to stand for 1-3 hours, then filtered and dried to obtain the aromatic diamine containing amide groups; more preferably, the amount of methanol added is 3-8 times the mass of the aromatic diamine.

[0058] The third objective of this invention is to provide an amide-containing aromatic diamine obtained by the above preparation method.

[0059] The fourth objective of this invention is to provide an application of an amide-containing aromatic diamine in polyimide.

[0060] The fifth objective of this invention is to provide a polyimide prepared by reacting a component comprising a diamine compound and a dianhydride compound; wherein the diamine compound is an amide-containing aromatic diamine as described in any one of claims 1 to 3, 8;

[0061] Preferably, the structure of the dianhydride compound is as follows:

[0062]

[0063] Wherein, A is a cycloalkane group, a bicycloalkane group, an aromatic group, an aromatic ether group, or an aromatic methyl ketone group.

[0064] The preparation method of the polyimide described in this invention is not particularly limited. A known method can be used to obtain the polyimide precursor—polyamic acid—and then imidization can be completed by thermal imidization or chemical imidization to obtain the polyimide. Thermal imidization is preferred in this invention.

[0065] The sixth objective of this invention is to provide an application of polyimide in substrates, color filters, printed materials, luminescent materials, electronic devices, flexible displays, liquid crystal display devices, electronic paper, and optical films.

[0066] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0067] Compared with existing technologies, the first-step amidation reaction of this invention uses p-nitrobenzoic acid as a raw material instead of p-nitrobenzoyl chloride, and uses propylphosphine anhydride as a dehydrating agent, thus avoiding the introduction of chloride ions. The process of preparing amide-containing aromatic diamines provided by this invention eliminates the post-treatment step of the first-step amidation. After the first-step reaction is completed, the reaction solution can be directly subjected to the second-step electroreduction nitro reaction after adjustment, making the route shorter. The second-step nitro reduction of this invention adopts an electrochemical reduction method, avoiding the use of hydrogen. In the electroreduction step, a halogen-free quaternary ammonium salt is used as the electrolyte, avoiding the introduction of halogens. The purification method is simple, without the use of halogen-containing reagents and sodium-containing reagents, thus avoiding the introduction of chloride ions and sodium ions. The total product yield is over 95%, higher than existing technologies. The whiteness of the product is over 73, higher than existing technologies. The process route of this invention does not use expensive and consumed palladium-carbon catalysts and eliminates a post-treatment step, making it more energy-efficient and lower in manufacturing cost compared with existing technologies. The total yield of the purified reaction is over 94%, higher than existing technologies.

[0068] In this invention, the compound obtained by the preparation method can be used to prepare polyimide and polyimide film. The polyimide and polyimide film have good heat resistance, high transparency, low water absorption, low dielectric constant, and still have a low coefficient of linear thermal expansion at high temperature. Therefore, they can be widely used in various electrical and optical components. Attached Figure Description

[0069] Figure 1 The 1H NMR spectrum of N,N'-(2,2'-bis(trifluoromethyl)-[1,1-diphenyl]-4,4'-diamino)bis(4-aminobenzamide) prepared in Example 2 is shown. Detailed Implementation

[0070] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0071] All raw materials used in the examples are commercially available.

[0072] Test method:

[0073] The coefficient of linear thermal expansion (CTE) was measured using a thermomechanical analyzer under a nitrogen atmosphere with a load of 50 mN and a heating rate of 10 °C / min. The average value was then calculated.

[0074] Glass transition temperature (Tg): The glass transition temperature was determined by DSC under a nitrogen atmosphere at a heating rate of 10 °C / min using a differential scanning calorimeter.

[0075] Total light transmittance (TT): Total light transmittance was measured using a UV-Vis spectrometer.

[0076] Transmittance at 400 nm (T): Transmittance was measured at 400 nm using an ultraviolet spectrophotometer.

[0077] Water absorption rate (RMA): Three 40×20cm polyimide films were dried at 120℃ for 2 hours and then left to stand in a constant temperature and humidity chamber at 23℃ / 50%RH for more than 24 hours. The weight change before and after drying was calculated by the following formula: RMA (%) = [(weight after moisture absorption - weight after drying) / weight after drying] × 100%.

[0078] Dielectric constant: The dielectric constant at 10 GHz was measured using a Keysight SPDR measuring instrument.

[0079] Example 1

[0080]

[0081] In a 250 mL round-bottom flask, 1.08 g (0.01 mol) of p-phenylenediamine, 50 g of N,N-dimethylformamide, 3.57 g (0.021 mol) of p-nitrobenzoic acid, and 6.68 g (0.021 mol) of propylphosphonic anhydride (T3P) were added sequentially. The mixture was stirred at room temperature for 3 h. Then, 5 g of acetic acid and 5 g of tetrabutylammonium acetate were added to the system. The mixture was placed in the cathode cell of an H-type electrolytic cell. The anode cell and cathode cell were separated by a Nafion membrane. In the anode cell of the H-type electrolytic cell, 50 g of N,N-dimethylformamide and 5 g of tetrabutylammonium acetate were added, followed by 5 g of 69 wt% hydrazine hydrate. Pt metal was used as the cathode electrode material, and carbon rods were used as the anode electrode material. The voltage was set to 0.75 V, and direct current was applied. The mixture was stirred at room temperature for 6 h, and the reaction was monitored by TLC until it was complete. Add 450g of distilled water to the cathode reaction solution. A large amount of white solid precipitates out. After standing for 30 minutes, filter the solid. Disperse the filter cake in 40g of 10wt% ammonium carbonate solution and slurry at room temperature for 6 hours. Filter the solid again. Slurry the filter cake with 25g of distilled water at room temperature for 6 hours. Filter the solid again. Dry the filter cake at 50℃ to obtain crude product. Then slurry it with 8g of methanol at 60℃ for 4 hours. Cool to room temperature, stand for 1 hour, filter, and dry to obtain 3.29g of compound 3. The yield is 95%, the purity is 99.9%, and no chloride or sodium ions were detected. The whiteness is 74.3. The whiteness measurement reference standard is GB / T 34321-2017.

[0082] 1 H-NMR (400MHz, DMSO-6d) δ9.05 (s, 2H), 7.82 (d, J = 8.4 Hz, 4H), 7.73 (s, 4H), 6.62 (d, J = 8.4 Hz, 4H), 4.21 (s, 4H).

[0083] Example 2

[0084]

[0085] In a 250 mL round-bottom flask, 3.2 g (0.01 mol) of compound 4, 150 g of dimethyl sulfoxide, 3.34 g (0.02 mol) of p-nitrobenzoic acid, and 7.5 g (0.024 mol) of propylphosphonic anhydride (T3P) were added sequentially. The mixture was stirred at room temperature for 5 h. Then, 3.2 g of acetic acid and 15.2 g of tetrabutylcarboxylate were added to the system. The mixture was placed in the cathode cell of an H-type electrolytic cell. The anode cell and cathode cell were separated by a Nafion membrane. 150 g of dimethyl sulfoxide and 15.2 g of tetrabutylcarboxylate were added to the anode cell of the H-type electrolytic cell. Then, 6.4 g of 69 wt% hydrazine hydrate was added. Pt metal was used as the cathode electrode material, and carbon rod was used as the anode electrode material. The voltage was set to 1.0 V, and direct current was applied. The mixture was stirred at room temperature for 12 h, and the reaction was monitored by TLC until it was complete. Add 1200g of distilled water to the cathode reaction solution. A large amount of white solid precipitates out. After standing for 30 minutes, filter the solid. Disperse the filter cake in 50g of 10% ammonium carbonate solution and slurry at room temperature for 4 hours. Filter the solid again. Slurry the filter cake with 50g of distilled water at room temperature for 4 hours. Filter the solid again. Dry the filter cake at 50℃ to obtain crude product. Then slurry the crude product with 12g of methanol at 60℃ for 4 hours. Cool to room temperature, stand for 1 hour, filter, and dry to obtain 5.35g of compound 5. The yield is 96%, the purity is 99.9%, and no chloride or sodium ions were detected. The whiteness of the product is 75.0.

[0086] 1 H-NMR (400MHz, DMSO-6d) δ10.15 (s, 2H), 8.32 (s, 2H), 8.06 (d, J = 8.4Hz, 2H), 7. 76(d,J=8.4Hz,4H), 7.31(d,J=8.4Hz,2H)), 6.63(d,J=8.4Hz,4H), 5.85(s,4H).

[0087] Example 3

[0088] In a 250 mL round-bottom flask, 3.2 g (0.01 mol) of compound 4, 32 g of N,N-dimethylacetamide, 3.34 g (0.02 mol) of p-nitrobenzoic acid, and 7.54 g (0.024 mol) of propylphosphonic anhydride (T3P) were added sequentially. The mixture was stirred at room temperature for 5 h. Then, 9 g of acetic acid and 6 g of tetrabutylammonium acetate were added to the system. The mixture was placed in the cathode cell of an H-type electrolytic cell. The anode cell and cathode cell were separated by a Nafion membrane. In the anode cell of the H-type electrolytic cell, 32 g of N,N-dimethylacetamide and 6 g of tetrabutylammonium acetate were added, followed by 7 g of 69 wt% hydrazine hydrate. Pt metal was used as the cathode electrode material, and carbon rods were used as the anode electrode material. The voltage was set to 1.0 V, and direct current was applied. The mixture was stirred at room temperature for 18 h, and the reaction was monitored by TLC until it was complete. Add 420g of distilled water to the cathode reaction solution. A large amount of white solid precipitates out. After standing for 30 minutes, filter the solid. Disperse the filter cake in 100g of 10wt% ammonium carbonate solution and slurry at room temperature for 4 hours. Filter the solid again. Slurry the filter cake with 50g of distilled water at room temperature for 4 hours. Filter the solid again. Dry the filter cake at 60°C to obtain a crude product. Then slurry the crude product with 24g of methanol at 50°C for 8 hours. Cool to room temperature, stand for 3 hours, filter, and dry to obtain 5.41g of compound 5. The yield is 97%, the purity is 99.9%, and no chloride or sodium ions were detected. The whiteness of the product is 75.2. The reaction formula is the same as in Example 2.

[0089] Example 4

[0090] In a 250 mL round-bottom flask, 3.2 g (0.01 mol) of compound 4, 100 g of N-methylpyrrolidone, 3.34 g (0.02 mol) of p-nitrobenzoic acid, and 9.54 g (0.03 mol) of propylphosphonic anhydride (T3P) were added sequentially. The mixture was stirred at room temperature for 8 h. Then, 16 g of acetic acid and 15 g of tetrabutylammonium acetate were added to the system. The mixture was placed in the cathode cell of an H-type electrolytic cell. The anode cell and cathode cell were separated by a Nafion membrane. In the anode cell of the H-type electrolytic cell, 100 g of N-methylpyrrolidone and 15 g of tetrabutylammonium acetate were added, followed by 15 g of 69 wt% hydrazine hydrate. Pt metal was used as the cathode electrode material, and carbon rods were used as the anode electrode material. The voltage was set to 0.9 V, and direct current was applied. The mixture was stirred at room temperature for 18 h, and the reaction was monitored by TLC until it was complete. Add 900g of distilled water to the cathode reaction solution. A large amount of white solid precipitates out. After standing for 30 minutes, filter the solid. Disperse the filter cake in 50g of 10wt% ammonium carbonate solution and slurry at room temperature for 4 hours. Filter the solid again. Slurry the filter cake with 50g of distilled water at room temperature for 4 hours. Filter the solid again. Dry the filter cake at 50°C to obtain a crude product. Then slurry the crude product with 22g of methanol at 55°C for 8 hours. Cool to room temperature, stand for 2 hours, filter, and dry to obtain 5.35g of compound 5. The yield is 96%, the purity is 99.9%, and no chloride or sodium ions were detected. The whiteness of the product is 74.3. The reaction formula is the same as in Example 2.

[0091] Example 5

[0092] In a 250 mL round-bottom flask, 3.2 g (0.01 mol) of compound 4, 50 g of N,N-dimethylformamide, 3.34 g (0.01 mol) of p-nitrobenzoic acid, and 9.54 g (0.03 mol) of propylphosphonic anhydride (T3P) were added sequentially. The mixture was stirred at room temperature for 8 h. Then, 10 g of acetic acid and 10 g of tetrabutylammonium acetate were added to the system. The mixture was placed in the cathode cell of an H-type electrolytic cell. The anode cell and cathode cell were separated by a Nafion membrane. In the anode cell of the H-type electrolytic cell, 50 g of N,N-dimethylformamide and 10 g of tetrabutylammonium acetate were added, followed by 6.4 g of 69 wt% hydrazine hydrate. Pt metal was used as the cathode electrode material, and carbon rods were used as the anode electrode material. The voltage was set to 0.85 V, and direct current was applied. The mixture was stirred at room temperature for 15 h, and the reaction was monitored by TLC until it was complete. Adding 400g of distilled water to the cathode reaction solution resulted in the precipitation of a large amount of white solid. After standing for 30 minutes, the mixture was filtered. The filter cake was dispersed in 50g of a 10wt% ammonium carbonate solution and stirred at room temperature for 4 hours. After filtration, the filter cake was stirred again with 60g of distilled water at room temperature for 4 hours. After filtration, the filter cake was dried at 55°C to obtain a crude product. Then, it was stirred with 24g of methanol at 55°C for 8 hours, cooled to room temperature, and allowed to stand for 2 hours. After filtration and drying, 5.44g of compound 5 was obtained, with a yield of 97.5% and a purity of 99.9%. No chloride or sodium ions were detected. The whiteness of the product was 75.6. The reaction formula was the same as in Example 2.

[0093] Example 6

[0094] In a 500 mL round-bottom flask, 16 g (0.05 mol) of compound 4, 160 g of N,N-dimethylacetamide, 16.7 g (0.1 mol) of p-nitrobenzoic acid, and 35 g (0.11 mol) of propylphosphonic anhydride (T3P) were added sequentially. The mixture was stirred at room temperature for 8 h. Then, 40 g of acetic acid and 28 g of tetrabutylammonium acetate were added to the system. The mixture was placed in the cathode cell of an H-type electrolytic cell. The anode cell and cathode cell were separated by a Nafion membrane. In the anode cell of the H-type electrolytic cell, 160 g of N,N-dimethylacetamide and 28 g of tetrabutylammonium acetate were added, followed by 40 g of 69 wt% hydrazine hydrate. Pt metal was used as the cathode electrode material, and carbon rods were used as the anode electrode material. The voltage was set to 1.1 V, and direct current was applied. The mixture was stirred at room temperature for 24 h, and the reaction was monitored by TLC until it was complete. Add 1.5 kg of distilled water to the cathode reaction solution. A large amount of white solid precipitates out. After standing for 30 min, filter the solid. Disperse the filter cake in 80 g of 10 wt% ammonium carbonate solution and slurry at room temperature for 6 h. Filter the solid again. Slurry the filter cake with 80 g of distilled water at room temperature for 4 h. Filter the solid again. Dry the filter cake at 60 °C to obtain a crude product. Then slurry the crude product with 64 g of methanol at 50 °C for 8 h. Cool to room temperature, stand for 3 h, filter, and dry to obtain 5.41 g of compound 5. The yield is 97%, the purity is 99.9%, and no chloride or sodium ions were detected. The whiteness of the product is 76.0. The reaction formula is the same as in Example 2.

[0095] Example 7

[0096] In a 250 mL round-bottom flask, 3.2 g (0.01 mol) of compound 4, 50 g of N,N-dimethylformamide, 3.34 g (0.01 mol) of p-nitrobenzoic acid, and 10.8 g (0.03 mol) of butylphosphine were added sequentially. The mixture was stirred at room temperature for 8 h. Then, 10 g of benzoic acid and 10 g of tetrabutylammonium acetate were added to the system. The mixture was placed in the cathode cell of an H-type electrolytic cell. The anode cell and cathode cell were separated by a Nafion membrane. In the anode cell of the H-type electrolytic cell, 50 g of N,N-dimethylformamide and 10 g of tetrabutylammonium acetate were added, followed by 6.4 g of 69 wt% hydrazine hydrate. Pt metal was used as the cathode electrode material, and carbon rods were used as the anode electrode material. The voltage was set to 0.85 V, and direct current was applied. The mixture was stirred at room temperature for 15 h, and the reaction was monitored by TLC until it was complete. Add 400g of distilled water to the cathode reaction solution. A large amount of white solid precipitates out. After standing for 30 minutes, filter the solid. Disperse the filter cake in 50g of 10wt% ammonium carbonate solution and slurry at room temperature for 4 hours. Filter the solid again. Slurry the filter cake with 60g of distilled water at room temperature for 4 hours. Filter the solid again. Dry the filter cake at 55°C to obtain a crude product. Then slurry the crude product with 24g of methanol at 55°C for 8 hours. Cool to room temperature, stand for 2 hours, filter, and dry to obtain 5.36g of compound 5. The yield is 96.1%, the purity is 99.9%, and no chloride or sodium ions were detected. The whiteness of the product is 76.8. The reaction formula is the same as in Example 2.

[0097] Example 8

[0098] Under 0°C and nitrogen atmosphere conditions, 5.584 g (10 mmol) of AB-TFMB prepared in Example 2 was dissolved in 22 mL of N,N-dimethylacetamide, and 2.246 g (10.02 mmol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride was slowly added. N,N-dimethylacetamide was added in three portions, totaling 8 mL, over half an hour of reaction. The solid content of the resulting system was 22 wt%. After stirring for 12 h, the reaction solution was transferred to a vacuum oven and degassed at room temperature to obtain a homogeneous polyamic acid (PAA) solution. PAA adhesive solution was cast onto a glass plate to form a film, which was then transferred to a muffle furnace for thermal imidization. The solvent was removed by holding the film at 40°C for 100 min under vacuum. The temperature was then increased to 100°C at a rate of 2°C / min and held at 100°C for 3 h. The temperature was then increased to 200°C at a rate of 2°C / min and held at 200°C for 2 h. The temperature was then increased to 300°C at a rate of 2°C / min and held at 300°C for 2 h. Thermal imidization was then completed, resulting in a polyamic acid film with a thickness of 18 μm.

[0099] Example 9

[0100] Under 0°C and nitrogen atmosphere conditions, 5.584 g (10 mmol) of AB-TFMB prepared in Example 2 was dissolved in 22 mL of N,N-dimethylacetamide, and 1.963 g (10.01 mmol) of 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride was slowly added. N,N-dimethylacetamide was added in three portions totaling 8 mL over half an hour of reaction, and the solid content of the resulting system was 21 wt%. After stirring the reaction for 12 h, the reaction solution was transferred to a vacuum oven and degassed at room temperature to obtain a homogeneous polyamic acid solution (PAA solution). PAA adhesive solution was cast onto a glass plate to form a film, which was then transferred to a muffle furnace for thermal imidization. The solvent was removed by holding the film at 40°C for 100 min under vacuum. The temperature was then increased to 100°C at a rate of 2°C / min and held at 100°C for 3 h. The temperature was then increased to 200°C at a rate of 2°C / min and held at 200°C for 2 h. The temperature was then increased to 300°C at a rate of 2°C / min and held at 300°C for 2 h. Thermal imidization was then completed, resulting in a polyamic acid film with a thickness of 18 μm.

[0101] Comparative Example 1

[0102] Market Procurement Purchased from Maclean's Reagent Company, it is light pink with a whiteness of 69.8. The whiteness reference standard is GB / T 34321-2017. The measured chloride ion content is 101 ppm and the sodium ion content is 105 ppm.

[0103] Comparative Example 2

[0104]

[0105] In a 250 mL round-bottom flask, 3.2 g of compound 4 and 40 g of ethyl acetate were added sequentially. Under stirring, 3.75 g of p-nitrobenzoyl chloride and 1.6 g of pyridine were added. The mixture was stirred at room temperature for 12 h. After the reaction was completed by TLC, 100 g of distilled water was added and the mixture was stirred for 1 h. The mixture was then filtered. The filter cake was slurried with 20 g of 10% sodium carbonate at room temperature for 4 h and filtered again. The filter cake was then slurried with 40 g of distilled water at room temperature for 4 h and filtered again. The filter cake was dried to obtain 5.62 g of compound 7, with a yield of 91%.

[0106] 5.62 g of compound 7 was mixed with 40 g of methanol, and 0.17 g of palladium on carbon was added. Hydrogen gas was introduced, and the mixture was stirred at room temperature for 12 h. The reaction was monitored by TLC until it was complete. Then, palladium on carbon was removed by filtration, and methanol was evaporated to dryness. The solid was slurried with 40 g of ethyl acetate for 12 h, filtered, and then slurried with 40 g of distilled water for 12 h, filtered, and dried under vacuum to obtain 4.67 g of product 5, with a yield of 92% and a purity of 97.9%. The product was light pink with a whiteness of 68.8. The whiteness reference standard is GB / T 34321-2017. The chloride ion content was measured to be 157 ppm and the sodium ion content was 159 ppm.

[0107] Comparative Example 3

[0108] Under conditions of 4°C and nitrogen atmosphere, 3.20 g (10 mmol) of TFMB (2,2'-di(trifluoromethyl)diaminobiphenyl) was dissolved in 15 mL of N,N-dimethylacetamide, and 1.96 g (10.01 mmol) of 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride was slowly added. N,N-dimethylacetamide was added in three portions, totaling 8 mL, over half an hour of reaction. The resulting system had a solid content of 19 wt%. After stirring for 12 h, the reaction solution was transferred to a vacuum oven and degassed at room temperature to obtain a homogeneous polyamic acid (PAA) solution. PAA adhesive solution was cast onto a glass plate to form a film, which was then transferred to a muffle furnace for thermal imidization. The solvent was removed by holding the film at 40°C for 100 min under vacuum. The temperature was then increased to 100°C at a rate of 2°C / min and held at 100°C for 3 h. The temperature was then increased to 200°C at a rate of 2°C / min and held at 200°C for 2 h. The temperature was then increased to 300°C at a rate of 2°C / min and held at 300°C for 2 h. Thermal imidization was then completed, resulting in a polyamic acid film with a thickness of 18 μm.

[0109] The polyimide films obtained in Examples 8-9 and Comparative Example 3 were subjected to the performance tests shown in the following methods, and the results are shown in Table 1.

[0110] The coefficient of linear thermal expansion (CTE) was measured using a thermomechanical analyzer under a nitrogen atmosphere with a load of 50 mN and a heating rate of 10 °C / min. The average value was then calculated.

[0111] Glass transition temperature (Tg): The glass transition temperature was determined by DSC under a nitrogen atmosphere at a heating rate of 10 °C / min using a differential scanning calorimeter.

[0112] Total light transmittance (TT): Total light transmittance was measured using a UV-Vis spectrometer.

[0113] Transmittance at 400 nm (T): Transmittance was measured at 400 nm using an ultraviolet spectrophotometer.

[0114] Water absorption rate (RMA): Three 40×20cm polyimide films were dried at 120℃ for 2 hours and then left to stand in a constant temperature and humidity chamber at 23℃ / 50%RH for more than 24 hours. The weight change before and after drying was calculated by the following formula: RMA (%) = [(weight after moisture absorption - weight after drying) / weight after drying] × 100%.

[0115] Dielectric constant: The dielectric constant at 10 GHz was measured using a Keysight SPDR measuring instrument.

[0116] As can be seen from Comparative Examples 1 and 2, the yield of the prior art is lower than that of the technical route of this invention, and the whiteness and ion content are also lower than those of the products obtained by the technical route of this invention. The polyimide prepared by AB-TFMB using the method of this invention exhibits lower water absorption and dielectric constant, and still has a low coefficient of linear thermal expansion at high temperatures.

[0117] Table 1

[0118]

[0119] As shown in Table 1, compared with Comparative Example 3, Example 9 has a higher glass transition temperature, lower water absorption, lower linear thermal expansion coefficient, and lower dielectric constant, proving that the AB-TFMB prepared in Example 2 has better performance than TFMB and is more suitable for application in electrical and optical components.

[0120] Examples 1-7 show that the yield of amide-containing aromatic diamines was 95-97.5%, the purity was 99.9%, chloride and sodium ions were not detected, and the whiteness was 74.3-76.8. In comparison, the commercially available amide-containing aromatic diamine of Comparative Example 1 had a whiteness of 69.8, was light pink, had a chloride ion content of 101 ppm, and a sodium ion content of 105 ppm; Comparative Example 2 had a yield of 92%, a purity of 97.9%, a chloride ion content of 157 ppm, a sodium ion content of 159 ppm, and a whiteness of 68.8, also light pink. This demonstrates that the preparation method of the present invention yields amide-containing aromatic diamines with higher yield and purity, avoids the introduction of chloride and sodium ions, and has higher whiteness, representing a significant improvement over existing preparation methods.

[0121] The polyimide films prepared in Examples 8 and 9 have a glass transition temperature of 372–374 °C, a total light transmittance (TT) of 86.2–84.6%, a light transmittance (T) of 80.2–81.6% at 400 nm, a water absorption rate (RMA) of 0.35–0.37, a linear coefficient of thermal expansion (CTE) of 17–19 ppm / k, and a dielectric constant of 2.64–2.67. They exhibit good heat resistance, high transparency, low water absorption, and low dielectric constant, and still possess a low linear coefficient of thermal expansion at high temperatures. Therefore, they can be widely used in various electrical and optical components.

Claims

1. An amide-containing aromatic diamine having a structure of: Ar is a group having an aromatic ring structure; preferably, Ar is one of the following structures: wherein 2. The amide-containing aromatic diamine according to claim 1, wherein: the amide-containing aromatic diamine is prepared by reacting components including an aromatic diamine, p-nitrobenzoic acid, an alkyl phosphoric anhydride, a polar aprotic organic solvent, a carboxylic acid, a halogen-free organic electrolyte, a metal ion-free reducing agent, an inorganic base, and a beating solvent.

3. The amide-containing aromatic diamine according to claim 2, wherein: the aromatic diamine is one of the following compounds: and / or, the alkyl phosphoric anhydride is at least one of propyl phosphoric anhydride, butyl phosphoric anhydride, and 1-ethylphosphonic acid cyclic anhydride; and / or, the polar aprotic organic solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; and / or, the carboxylic acid is at least one of acetic acid, propionic acid, butyric acid, and benzoic acid; and / or, the halogen-free organic electrolyte is at least one of a halogen-free quaternary ammonium salt, N-butylpyridinium methanesulfonate, and N-hexyl-3-methylpyridinium methanesulfonate; the halogen-free quaternary ammonium salt is preferably at least one of tetrabutylammonium acetate, tetrabutylammonium formate, tetrabutylammonium sulfate, tetrabutylammonium bisulfate, tetrabutylammonium phosphate, tetrabutylammonium methanesulfonate, tetramethylammonium phosphate, tetramethylammonium sulfate, tetramethylammonium bisulfate, tetramethylammonium acetate, tetramethylammonium formate, tetramethylammonium methanesulfonate, tetraethylammonium acetate, tetraethylammonium formate, tetraethylammonium phosphate, tetraethylammonium sulfate, tetraethylammonium bisulfate, tetraethylammonium methanesulfonate, benzyltrimethylammonium acetate, benzyltrimethylammonium formate, benzyltrimethylammonium methanesulfonate, benzyltrimethylammonium phosphate, benzyltrimethylammonium sulfate, benzyltrimethylammonium bisulfate, and tetrapropylammonium bisulfate; and / or, the metal ion-free reducing agent is hydrazine hydrate; and / or, the inorganic base is at least one of ammonium carbonate and aqueous ammonia; the concentration of the aqueous ammonia is preferably 1 to 10 wt%; and / or, the beating solvent is at least one of methanol, ethanol, ethyl acetate, and methyl tert-butyl ether.

4. A method for preparing an amide-containing aromatic diamine, comprising the following steps: (1) mixing and reacting components including an aromatic diamine, p-nitrobenzoic acid, an alkyla phosphoric anhydride, and a polar aprotic organic solvent; (2) adding a carboxylic acid and a halogen-free organic electrolyte to the product obtained in step (1) to obtain a mixed solution, and placing the mixed solution in a cathode cell of an H-type electrolytic cell; the anode cell and the cathode cell are separated by a Nafion membrane; the same polar aprotic organic solvent and halogen-free organic electrolyte as those in the cathode cell are added to the anode cell of the H-type electrolytic cell, and a metal ion-free reducing agent is added, and electricity is applied to perform a reaction; (3) purifying the cathode reaction solution obtained in step (2) after the reaction to obtain the amide-containing aromatic diamine; preferably, the method is used to prepare the amide-containing aromatic diamine according to any one of claims 1 to 3.

5. The method for preparing an amide-containing aromatic diamine according to claim 4, wherein: in step (1), ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The molar ratio of the aromatic diamine, p-nitrobenzoic acid, and alkyl phosphoric anhydride is 1:(2-4):(2.1-5), preferably 1:(2-2.1):(2.1-3); and / or, The polar aprotic organic solvent is added in an amount of 5-100 times, preferably 10-50 times, the mass of the aromatic diamine; and / or, The reaction is stirred at room temperature, and the reaction time is 3-8 hours.

6. The method for preparing the amide-containing aromatic diamine according to claim 4, characterized in that: Step (2), The carboxylic acid is added in the cathode tank in an amount of 0.5-8 times, preferably 1-5 times, the mass of the aromatic diamine; and / or, The halogen-free organic electrolyte is added in the cathode tank in an amount of 0.5-8 times, preferably 1-5 times, the mass of the aromatic diamine; and / or, The polar aprotic organic solvent and the halogen-free organic electrolyte are added in the anode tank in the same amount as in the cathode tank; and / or, When the metal ion-free reducing agent is hydrazine hydrate, the effective content of hydrazine in the hydrazine hydrate is 40-69 wt%, and the hydrazine hydrate is added in the anode tank in an amount of 1-8 times, preferably 2-5 times, the mass of the aromatic diamine; and / or, The cathode uses metal Pt as the electrode material; and / or, The anode uses a carbon rod as the electrode material; and / or, Direct current is passed, and the voltage is 0.75-1.1 V; and / or, The reaction is carried out under stirring; and / or, The reaction temperature is 20-45°C; and / or, The reaction time is 2-48 hours, preferably 6-24 hours.

7. The method for preparing the amide-containing aromatic diamine according to claim 4, characterized in that: Step (3), The post-treatment includes precipitation, suction filtration, and drying; preferably, the post-treatment is adding water to the cathode reaction solution after the reaction to precipitate the solid, suction filtration to obtain a filter cake, and then dispersing the filter cake in an ammonium carbonate solution, suction filtration, mixing with water, suction filtration, mixing with methanol, suction filtration, and drying to obtain the amide-containing aromatic diamine; Further preferably, Distilled water is added to the cathode reaction solution after the reaction in step (2), and suction filtration is carried out after standing for 20-40 minutes to obtain a filter cake A; more preferably, the amount of distilled water added is 4-10 times the total mass of the reaction solution in the cathode tank; and / or, The filter cake A is dispersed in an ammonium carbonate solution, and the pulp is beaten at room temperature for 4-6 hours, and suction filtration is carried out to obtain a filter cake B; more preferably, the concentration of the ammonium carbonate solution is 5-20 wt%, and / or the mass of the ammonium carbonate solution added is 5-50 times the mass of the aromatic diamine raw material; and / or, The filter cake B is added to distilled water, and the pulp is beaten at room temperature for 4-6 hours, and suction filtration to obtain a filter cake C; more preferably, the mass of the distilled water added is 4-30 times the mass of the aromatic diamine raw material; and / or, The filter cake C is dried to obtain the crude amide-containing aromatic diamine; the drying temperature is preferably 50-60°C; and / or, The crude amide-containing aromatic diamine is added to methanol, the pulp is beaten at 50-60°C for 4-8 hours, cooled to room temperature, and then suction filtration and drying are carried out to obtain the amide-containing aromatic diamine; more preferably, the amount of methanol added is 3-8 times the mass of the aromatic diamine.

8. An amide-containing aromatic diamine obtained by the method according to any one of claims 4-7.

9. The use of an amide-containing aromatic diamine as described in any one of claims 1 to 3, 8 in polyimide.

10. A polyimide prepared by reacting a component comprising a diamine compound and a dianhydride compound; wherein the diamine compound is an amide-containing aromatic diamine according to any one of claims 1 to 3, 8; Preferably, the structure of the dianhydride compound is as follows: wherein, A is a cycloalkane group, a bicycloalkane group, an aromatic group, an aromatic ether group, or an aromatic methyl ketone group.

11. The application of the polyimide as described in claim 10 in substrates, color filters, printed materials, luminescent materials, electronic devices, flexible displays, liquid crystal display devices, electronic paper, and optical films.

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