Aromatic diamine intermediate with multiple methyl groups and amido bonds as well as preparation method and application of aromatic diamine intermediate

Abstract

The invention discloses a polymethyl and amido bond aromatic diamine intermediate and a preparation method and application thereof.The aromatic diamine intermediate contains an amido group and a polymethyl group at the same time, and the amido group and the polymethyl group act synergistically to prepare a high-molecular polymer. The heat resistance of the polymer is improved; meanwhile, the colorless transparent performance is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic fine chemical synthesis, and particularly relates to an aromatic diamine intermediate with polymethyl and amide bonds, a preparation method thereof, and an application thereof. Background Art

[0002] With the development and progress of modern technology, industries such as microelectronic packaging, flexible display, separation membrane, insulating material, and solar cell substrate have put forward further requirements for the performance of materials. Since the high molecular polymers prepared from diamine monomers on the market mainly feature high mechanical properties and good electrical insulation properties, while the high molecular polymers required by high-tech industries such as electronic information are developing towards functionalization directions such as colorless transparency, high heat resistance, and low coefficient of thermal expansion. Currently, the disclosed functional diamine intermediates are often aliphatic, fluorine-containing, with large side groups, etc., and there are few reports on new intermediates for similar functionalization requirements.

[0003] In current research, there are usually two paths to achieve the high transparency and high heat resistance functionalization of polymers. One type is to introduce trifluoromethyl groups into the intermediate, using trifluoromethyl groups to increase the intermolecular spacing and prevent the transmission of the CTC effect between molecules; and due to the strong electronegativity of fluorine atoms, prevent the transmission of CTC in the molecular chain, and minimize the yellowing of the polymer to achieve the purpose of colorless transparency. However, as a strongly electronegative element, it is difficult to synthesize such diamines, and they are relatively expensive and highly toxic. The other type is aliphatic polymers. Although by adding aliphatic structures, the conjugation effect brought by the benzene ring is eliminated, and the transmission of the CTC effect is prevented. However, compared with aromatic polymers, the heat resistance of aliphatic polymers shows a precipitous decline, which is a fatal problem for polymers.

[0004] Chinese patent document CN 114644563A discloses a diamine monomer containing aromatic ester groups and a symmetric fluorobenzene structure, a preparation method thereof, and an application thereof. The functional group structure of the diamine monomer includes aromatic ester groups and a symmetric fluorobenzene structure. Due to the introduction of fluorine elements in the monomer, the cost of raw materials is increased and the toxicity is increased. Summary of the Invention

[0005] In order to overcome the problems in the prior art, the present invention provides an aromatic diamine intermediate with polymethyl and amide bonds, a preparation method thereof, and an application thereof, realizing the functions of polymer transparency and improvement of heat resistance.

[0006] To solve the above technical problems, the technical solution proposed by the present invention is as follows: The present invention provides an aromatic diamine intermediate with polymethyl and amide bonds, having the structure shown in the following formula:

[0007] Wherein, is one of the following structures, , or

[0008] wherein, exactly one of R2, R3, R4, R5, and R6 is NH2, and at least two of the remaining groups and R7, R8, R9, and R10 are -CH3, and the rest are H.

[0009] Introducing an amide bond into the intermediate in the present invention can achieve the hydrogen bond effect of the polymer, resulting in a large number of hydrogen bonds between molecular weights, thereby meeting the requirement of increasing the glass transition temperature of the material when applied to the polymer and achieving an improvement in heat resistance. At the same time, introducing multiple methyl groups on the benzene ring, using the steric hindrance effect of the multiple methyl groups, can increase the intermolecular distance of the polymer. Meanwhile, using the characteristics of the multiple methyl groups as electron-donating groups, the intramolecular electron transfer of the polymer can be reduced, thereby achieving the transparent functionalization of the polymer. The amide group and the multiple methyl groups in the present invention cooperate. After being prepared into a polymer, while improving the heat resistance of the polymer, its colorless transparency is further increased.

[0010] As an alternative embodiment, among the intermediates provided by the present invention, the intermediate is selected from one or more of 1,3-bis(4-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(3-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2,6-dimethyl-4-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(5-methyl-3-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(4,5-dimethyl-2-aminobenzamido)-2,4,6-trimethylbenzene, 1,4-bis(4-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(3-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(2-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(2,6-dimethyl-4-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(5-methyl-3-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(4,5-dimethyl-2-aminobenzamido)-2,5-dimethylbenzene, 1,2-bis(4-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(3-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(2-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(2,6-dimethyl-4-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(5-methyl-3-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(4,5-dimethyl-2-aminobenzamido)-4,5-dimethylbenzene.

[0011] Based on the same technical concept, the present invention also provides a method for preparing the aromatic diamine intermediate with polymethyl and amide bonds, comprising the following steps: S1. Under an inert atmosphere, one of 2,4,6-trimethyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine or 4,5-dimethyl-1,2-phenylenediamine and nitrobenzoyl chloride are added to an organic solvent, and then an acid-binding agent is added. After reaction, a solution containing a bis-nitro product is obtained, and the bis-nitro product after reaction is obtained after solution treatment; S2. Under an inert atmosphere, the bis-nitro product in step S1 is added to an organic solvent, and then a catalytic reduction reaction is carried out to obtain a solution containing an aromatic diamine with polymethyl and amide bonds. After solution treatment, an aromatic diamine intermediate with polymethyl and amide bonds is obtained.

[0012] As an alternative embodiment, in the preparation method provided by the present invention, the nitrobenzoyl chloride is selected from one or more of m-nitrobenzoyl chloride, p-nitrobenzoyl chloride, o-nitrobenzoyl chloride, 2,6-dimethyl-4-nitro-benzoyl chloride, 5-methyl-3-nitro-benzoyl chloride or 4,5-dimethyl-2-nitro-benzoyl chloride.

[0013] As an alternative embodiment, in the preparation method provided by the present invention, the aromatic diamine intermediate with multi-methyl and amide bonds is selected from one or more of 1,3-bis(4-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(3-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2,6-dimethyl-4-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(5-methyl-3-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(4,5-dimethyl-2-nitrobenzamido)-2,4,6-trimethylbenzene, 1,4-bis(4-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(3-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(2-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(2,6-dimethyl-4-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(5-methyl-3-nitrobenzamido)-2,5-dimethylbenzene or 1,4-bis(4,5-dimethyl-2-nitrobenzamido)-2,5-dimethylbenzene, 1,2-bis(4-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(3-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(2-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(2,6-dimethyl-4-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(5-methyl-3-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(4,5-dimethyl-2-nitrobenzamido)-4,5-dimethylbenzene.

[0014] As an alternative embodiment, in the preparation method provided by the present invention, in step S1, the molar ratio of 2,4,6-trimethyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine or 4,5-dimethyl-1,2-phenylenediamine to nitrobenzoyl chloride is 1:2 to 1:2.2.

[0015] In the present invention, controlling the molar ratio of 2,4,6-trimethyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine or 4,5-dimethyl-1,2-phenylenediamine to nitrobenzoyl chloride within the above range is beneficial to ensuring the completeness of the reaction and simplifying the subsequent purification process.

[0016] As an alternative embodiment, in the preparation method provided by the present invention, in steps S1 and S2, the solution treatment process is filtration, recrystallization, drying, recrystallization, and re-drying.

[0017] As an alternative embodiment, in the preparation method provided by the present invention, the acid-binding agent is selected from one or more of quinoline, isoquinoline, pyridine, and triethylamine, and the molar amount of the acid-binding agent is 2 to 4 times the molar amount of 2,4,6-trimethyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, or 4,5-dimethyl-1,2-phenylenediamine.

[0018] As an alternative embodiment, in the preparation method provided by the present invention, the reducing agent is hydrazine hydrate, and the amount of the reducing agent used is 2 ml to 3 ml of hydrazine hydrate per 1 mmol of the aromatic diamine intermediate with polymethyl and amide bonds.

[0019] As an alternative embodiment, in the preparation method provided by the present invention, the catalyst is palladium / carbon, and the amount of the catalyst used is 0.02 to 0.05 g of palladium / carbon per 1 mmol of the aromatic diamine intermediate with polymethyl and amide bonds.

[0020] In the present invention, controlling the amounts of the acid-binding agent, reducing agent, and catalyst within the above ranges is beneficial to improving the yield of 1,3-bis(4-aminobenzamido)-2,4,6-trimethylbenzene and facilitating the subsequent purification of the product.

[0021] As an alternative embodiment, in the preparation method provided by the present invention, in step S1, the reaction is carried out in an ice-water bath, and the reaction time is 6 to 12 h.

[0022] As an alternative embodiment, in the preparation method provided by the present invention, in step S3, the temperature of the reaction system is 80 to 120 °C, and the reaction time is 6 to 12 h.

[0023] Controlling the temperature of the reaction system at 80 to 120 °C is beneficial to the progress of the reaction. If the temperature is too high, other side reactions may occur.

[0024] As an alternative embodiment, in the preparation method provided by the present invention, in step S1, the organic solvent is selected from one or more of dichloromethane, chloroform, or dichloroethane; in step S3, the organic solvent is a mixture of ethanol and water; one or more of ethanol, methanol, water, and tetrahydrofuran are used in the recrystallization process.

[0025] Based on the same inventive concept, the present invention also provides the use of the above-mentioned aromatic diamine intermediate with polymethyl and amide bonds or the aromatic diamine intermediate with polymethyl and amide bonds prepared by the above-mentioned preparation method in the preparation of polyimide high molecular polymers, polyamide high molecular polymers, polyamide-imide high molecular polymers, and polyurea high molecular polymers.

[0026] Based on the same inventive concept, the present invention also provides the use of the above-mentioned aromatic diamine intermediate with polymethyl and amide bonds or the aromatic diamine intermediate with polymethyl and amide bonds prepared by the above-mentioned preparation method in the preparation of polyamide high molecular polymers, polyimide high molecular polymers, or urea high molecular polymers. The aromatic diamine intermediate with polymethyl and amide bonds reacts with diacyl chloride to obtain a polyamide high molecular polymer material, the aromatic diamine intermediate with polymethyl and amide bonds reacts with dianhydride to obtain a polyimide high molecular material, and the aromatic diamine intermediate with polymethyl and amide bonds reacts with diisocyanate to obtain a urea high molecular material.

[0027] As an alternative embodiment, in the application provided by the present invention, the preparation method of the polyimide high molecular polymer material includes the following steps: heating and reacting the aromatic diamine intermediate with polymethyl and amide bonds and the dianhydride monomer for polyimide synthesis in an aprotic solvent to obtain polyamic acid, and then imidizing the polyamic acid to obtain the polyimide high molecular polymer.

[0028] As an alternative embodiment, in the application provided by the present invention, the preparation method of the polyamide high molecular polymer material includes the following steps: heating and reacting the aromatic diamine intermediate with polymethyl and amide bonds and the diacyl chloride monomer for polyamide synthesis in an aprotic solvent to obtain a polyamide resin, and then curing the polyamide resin to obtain the polyamide high molecular polymer.

[0029] As an alternative embodiment, in the application provided by the present invention, the preparation method of the polyamide high molecular polymer includes the following steps: heating and reacting the aromatic diamine intermediate with polymethyl and amide bonds and the diisocyanate monomer for polyamide synthesis in an aprotic solvent to obtain a polyurea resin, and then curing the polyurea resin to obtain the polyurea high molecular polymer.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention creatively obtains a brand-new diamine intermediate. Through the synergistic effect of the amide bond and the polymethyl group, it not only meets the requirement of improving the glass transition temperature of the material when applied to the polymer, realizes the improvement of heat resistance, and thus meets the high heat resistance requirement of the polymer, but also makes the polymer have the property of being colorless and transparent.

[0031] (2) The present invention synthesizes an aromatic diamine intermediate compound with polymethyl and amide bonds through a relatively simple chemical synthesis route reaction. This preparation method has the characteristics of simple purification and high product yield. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 1H NMR spectrum of the product obtained in Example 1; Figure 2 Infrared spectrum of the product obtained in Example 1. Detailed Description of the Invention

[0034] For the convenience of understanding the present invention, the following will describe the present invention more comprehensively and meticulously in combination with the drawings in the specification and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0035] Unless otherwise defined, all the technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0036] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments, and equipment used in the present invention can be obtained through the market or prepared by existing methods.

[0037] Example 1 Preparation of 1,3-bis(4-aminobenzamido)-2,4,6-trimethylbenzene, including the following steps: Under nitrogen atmosphere, add a magnetic stirrer, 15.0 g (0.1 mol) of 2,4,6-trimethyl-1,3-phenylenediamine, 40 g (0.21 mol) of p-nitrobenzoyl chloride, and 300 mL of anhydrous dichloromethane to a 1000 mL three-necked flask. Add a condensing reflux device to the bottle mouth, and react in an ice-water bath to allow the reactants to fully dissolve in dichloromethane. When the reaction solution becomes a brown-black solution, add 0.3 mol of anhydrous pyridine as an acid-binding agent in batches to promote the forward reaction, and react for 6 h. After the reaction is completed, collect the brown-black filtrate. Pour the brown-black filtrate into a 2 L beaker and add 4 times the amount of deionized water. Cover the bottle mouth with plastic wrap and let it stand until all the products are precipitated. Filter, wash the product with methanol, and put it in an 80 °C vacuum drying oven for drying. Obtain a yellow-brown product, 1,3-bis(4-nitrobenzamide)-2,4,6-trimethylbenzene. Under a nitrogen atmosphere, add 1,3-bis(4-nitrobenzamide)-2,4,6-trimethylbenzene, 4g palladium / carbon, 250ml hydrazine hydrate, and 300mL of a mixed solution of ethanol: water = 3:1 to a 1000 mL branched bottle. Connect a condensing reflux device to the bottle mouth, heat the oil bath to 80 °C, react for 6 h, and end the reaction. Filter the reaction solution to obtain a colorless solution. Pour the colorless solution into a 2 L beaker and add 4 times the amount of deionized water. Cover the bottle mouth with plastic wrap, let it stand until all the products are precipitated, filter, wash the product with deionized water, put it into a freeze dryer for freeze drying and solvent removal, and obtain a white block solid with a yield of 85%.

[0038] The white block solid obtained in Example 1 was tested, and its nuclear magnetic resonance hydrogen spectrum was as follows Figure 1 As shown, Figure 1 It can be seen that the white block solid is 1,3-bis(4-aminobenzamide)-2,4,6-trimethylbenzene, which proves that it has a high purity.

[0039] The white block solid obtained in Example 1 was subjected to infrared spectroscopy detection. The results are as follows Figure 2 As shown, its successful synthesis is also demonstrated.

[0040] Example 2 Preparation of 1,3-bis(3-aminobenzamide)-2,4,6-trimethylbenzene, comprising the following steps; Compared with Example 1, only p-nitrobenzoyl chloride was replaced with 0.2 mol m-nitrobenzoyl chloride. The obtained off-white block solid was 1,3-bis(3-aminobenzamide)-2,4,6-trimethylbenzene with a yield of 80%.

[0041] Example 3 The preparation of 1,3-bis(2-aminobenzamide)-2,4,6-trimethylbenzene comprises the following steps: Compared with Example 1, only p-nitrobenzoyl chloride was replaced with 0.22 mol of o-nitrobenzoyl chloride. The obtained grayish-yellow massive solid was 1,3-bis(2-aminobenzamido)-2,4,6-trimethylbenzene, and the yield was 78%.

[0042] Example 4 The preparation of 1,3-bis(2,6-dimethyl-4-aminobenzamido)-2,4,6-trimethylbenzene comprises the following steps: Under a nitrogen atmosphere, in a 1000 mL three-necked flask, a magnetic stirrer, 15.0 g (0.1 mol) of 2,4,6-trimethyl-1,3-phenylenediamine, 44 g (0.2 mol) of 2,6-dimethyl-4-nitro-benzoyl chloride, and 300 mL of anhydrous dichloromethane were added. A condensation reflux device was added to the bottle mouth, and the reaction was carried out in an ice-water bath to allow the reactants to dissolve fully in dichloromethane. When the reaction solution became a brownish-black solution, 0.3 mol of anhydrous pyridine was added in batches as an acid-binding agent to promote the forward reaction, and the reaction was carried out for 6 h. After the reaction ended, a brownish-black filtrate was collected. The brownish-black filtrate was poured into a 2 L beaker, and 4 times the amount of deionized water was added. The bottle mouth was covered with a plastic wrap and left to stand until all the products were precipitated. Filtration was carried out, and the product was washed with methanol and then placed in a vacuum drying oven at 80 °C for drying. The brown product 1,3-bis(2,6-dimethyl-4-nitrobenzamido)-2,4,6-trimethylbenzene was obtained. Under a nitrogen atmosphere, in a 1000 mL side-necked flask, 1,3-bis(2,6-dimethyl-4-nitrobenzamido)-2,4,6-trimethylbenzene, 4 g of palladium / carbon, 250 ml of hydrazine hydrate, and a 300 mL mixed solution of ethanol:water = 3:1 were added. A condensation reflux device was connected to the bottle mouth, and the reaction was heated to 80 °C in an oil bath for 6 h to end the reaction. The reaction solution was filtered to obtain a colorless solution. The colorless solution was poured into a 2 L beaker, and 4 times the amount of deionized water was added. The bottle mouth was covered with a plastic wrap and left to stand until all the products were precipitated. Filtration was carried out, and the product was washed with deionized water and then placed in a freeze dryer to remove the solvent by freeze drying, obtaining a white massive solid with a yield of 83%.

[0043] Example 5 The preparation of 1,4-bis(4,5-dimethyl-2-aminobenzamido)-2,5-dimethylbenzene comprises the following steps: Under nitrogen atmosphere, in a 1000 mL three-necked flask, add a magnetic stirrer, 13.6 g (0.1 mol) of 2,5-trimethyl-1,4-phenylenediamine, 44 g (0.2 mol) of 2,5-dimethyl-2-nitro-benzoyl chloride, and 300 mL of anhydrous dichloromethane. Add a condensation reflux device to the bottle mouth, and react in an ice-water bath to allow the reactants to fully dissolve in dichloromethane. When the reaction solution becomes a brown-black solution, 0.3 mol of anhydrous pyridine is added in batches as an acid binding agent to promote the forward reaction, and the reaction is carried out for 6 h. After the reaction is completed, the brown-black filtrate is collected. Pour the brown-black filtrate into a 2 L beaker and add 4 times the amount of deionized water. Cover the bottle mouth with plastic wrap and let it stand until all the products are precipitated. Filter, wash the product with methanol, and put it in a vacuum drying oven at 80 °C for drying. The brown product 1,4-bis(4,5-dimethyl-2-nitrobenzamide)-2,5-dimethylbenzene was obtained. Under nitrogen atmosphere, 1,4-bis(4,5-dimethyl-2-nitrobenzamide)-2,5-dimethylbenzene, 4g palladium / carbon, 250ml hydrazine hydrate, and 300 mL mixed solution of ethanol: water = 3:1 were added to a 1000 mL branched bottle. A condensing reflux device was connected to the bottle mouth, and the oil bath was heated to 80 °C. The reaction was carried out for 6 h to terminate the reaction. The reaction solution was filtered to obtain a colorless solution. The colorless solution was poured into a 2 L beaker and 4 times the amount of deionized water was added. Cover the bottle mouth with plastic wrap, let it stand until all the products were precipitated, filter, wash the product with deionized water, put it into a freeze dryer for freeze drying and solvent removal, and a white block solid was obtained with a yield of 79%.

[0044] Example 6 Compared with Example 1, the amount of catalyst used was 2 g, the amount of reducing agent used was 300 ml, and the amount of acid binding agent used was 0.2 mol. The white block solid obtained was 1,3-bis(4-aminobenzamide)-2,4,6-trimethylbenzene with a yield of 60%.

[0045] Example 7 Compared with Example 1, the amount of catalyst used was 5 g, the amount of reducing agent used was adjusted to 200 ml, and the amount of acid binding agent used was 0.4 mol. The white block solid obtained was 1,3-bis(4-aminobenzamide)-2,4,6-trimethylbenzene with a yield of 70%.

[0046] Example 8 Compared with Example 1, only the amount of the acid-binding agent was adjusted to 0.12 mol, and the white block solid obtained was 1,3-bis(4-aminobenzamide)-2,4,6-trimethylbenzene with a yield of 30%.

[0047] Example 9 Compared with Example 1, only the acid-binding agent was adjusted to a dosage outside the scope of the claimed protection: 0.06 mol. A very small amount of brown blocky solid obtained in S1 was 1,3-bis(4-nitrobenzamido)-2,4,6-trimethylbenzene. The nitro yield was too low, there were too many impurities, and purification was relatively difficult.

[0048] Performance testing I. Prepare polyimide from 1,3-bis(4-aminobenzamido)-2,4,6-trimethylbenzene of Example 1. The specific process is as follows: In a 250 mL three-necked flask, dissolve 3.88 g (0.01 mol) of 1,3-bis(4-aminobenzamido)-2,4,6-trimethylbenzene prepared in Example 1 in 20.5 g of DMF. Under a nitrogen atmosphere, control the reaction temperature at 50 °C, stir evenly for 30 min, and then add 2.94 g (0.01 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride to the solution. React for 5 h until it reaches 5000 cP, continue stirring and reacting for 10 h, carry out vacuum defoaming, protect with nitrogen, and store at low temperature. Warm the above polyamic acid to 23 °C, and form a 10 μm thick coating on a silicon substrate through a spin coating device. Carry out reduced pressure drying at a pumping speed of 1 L / s and a temperature of 70 °C for 1 h to obtain a pre-cured PAA coating, and then transfer it to a high-temperature oven. Raise the temperature to 350 °C at a temperature increase rate of 5 °C / min, control the environmental oxygen concentration to be less than 100 ppm, and hold for 1 h to obtain a polyimide film.

[0049] II. Use 2,2'-bis(trifluoromethyl)diaminobiphenyl as a comparative diamine to prepare polyimide. The specific process is as follows: In a 250 mL three-necked flask, dissolve 3.2 g (0.01 mol) of 2,2'-bis(trifluoromethyl)diaminobiphenyl in 18.42 g of DMF. Under a nitrogen atmosphere, control the reaction temperature at 50 °C, stir evenly for 30 min, and then add 2.94 g (0.01 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride to the solution. React for 5 h until it reaches 5000 cP, continue stirring and reacting for 10 h, carry out vacuum defoaming, protect with nitrogen, and store at low temperature. Warm the above polyamic acid to 23 °C, and form a 10 μm thick coating on a silicon substrate through a spin coating device. Carry out reduced pressure drying at a pumping speed of 1 L / s and a temperature of 70 °C for 1 h to obtain a pre-cured PAA coating, and then transfer it to a high-temperature oven. Raise the temperature to 350 °C at a temperature increase rate of 5 °C / min, control the environmental oxygen concentration to be less than 100 ppm, and hold for 1 h to obtain a polyimide film.

[0050] III. Use 4,4'-diaminobenzanilide as a comparative diamine to prepare polyimide. The specific process is as follows: In a 250 mL three-necked flask, 2.27 g (0.01 mol) of 4,4'-diaminobenzanilide was dissolved in 15.63 g of DMF. Under a nitrogen atmosphere, the reaction temperature was controlled at 50 °C, and the mixture was stirred evenly for 30 min. Then, 2.94 g (0.01 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added to the solution, and the reaction was carried out for 5 h until it reached 5000 cP. The reaction was continued with stirring for 10 h, followed by vacuum defoaming and nitrogen protection, and then stored at low temperature. The above polyamic acid was warmed to 23 °C, and a 10-μm-thick coating was formed on a silicon substrate by a spin-coating device. After drying under reduced pressure at a pumping speed of 1 L / s and a temperature of 70 °C for 1 h, a pre-cured PAA coating was obtained. Then, it was transferred to a high-temperature oven and heated to 350 °C at a temperature rise rate of 5 °C / min while controlling the environmental oxygen concentration to be lower than 100 ppm and maintaining for 1 h to obtain a polyimide film.

[0051] The polyimide film prepared above was subjected to thermal and optical property tests, and the results are shown in Table 1 below.

[0052] Table 1: Thermal property test results of the polyimide film

[0053] As can be seen from Table 1, compared with the polyimide prepared from 2,2'-bis(trifluoromethyl)diaminobiphenyl, the polyimide prepared from 1,3-bis(4-aminobenzamido)-2,4,6-trimethylbenzene in Example 1 has similar yellowness and yellowness index, indicating that the polyimide prepared in this application is colorless and transparent. Judging from the data, the transparency is better than that of the colorless and transparent polyimide commonly used in the prior art prepared with trifluoromethyl. Compared with the polyimide prepared from 4,4'-diaminobenzanilide, it has a higher glass transition temperature and better heat resistance. And it also has a lower coefficient of thermal expansion.

[0054] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is limited only to these descriptions. For those of ordinary skill in the art to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. An aromatic diamine intermediate with multiple methyl groups and amide bonds, characterized in that, It has a structure shown by the following formula: Among them, is one of the following structures, , or Among them, only one of R2, R3, R4, R5, and R6 is NH2, and at least two of the remaining groups and R7, R8, R9, and R10 are -CH3, and the rest are H.

2. The aromatic diamine intermediate with polymethyl and amide bonds according to claim 1, characterized in that, The intermediate is selected from one or more of 1,3-bis(4-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(3-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2,6-dimethyl-4-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(5-methyl-3-aminobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(4,5-dimethyl-2-aminobenzamido)-2,4,6-trimethylbenzene, 1,4-bis(4-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(3-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(2-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(2,6-dimethyl-4-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(5-methyl-3-aminobenzamido)-2,5-dimethylbenzene, 1,4-bis(4,5-dimethyl-2-aminobenzamido)-2,5-dimethylbenzene, 1,2-bis(4-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(3-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(2-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(2,6-dimethyl-4-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(5-methyl-3-aminobenzamido)-4,5-dimethylbenzene, 1,2-bis(4,5-dimethyl-2-aminobenzamido)-4,5-dimethylbenzene.

3. The preparation method of the aromatic diamine intermediate with polymethyl and amide bonds as claimed in claim 1 or 2, characterized in that, It includes the following steps: S1. Under an inert atmosphere, one of 2,4,6-trimethyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine or 4,5-dimethyl-1,2-phenylenediamine and nitrobenzoyl chloride are added to an organic solvent, and then an acid-binding agent is added, and a reaction is carried out to obtain a solution containing a dinitro product. After treating the solution, the reacted dinitro product is obtained; S2. Under an inert atmosphere, the dinitro product in step S1 is added to an organic solvent, and then a catalytic reduction reaction is carried out to obtain a solution of an aromatic diamine containing polymethyl and amide bonds. After treating the solution, an aromatic diamine intermediate containing polymethyl and amide bonds is obtained.

4. The preparation method according to claim 3, characterized in that, The nitrobenzoyl chloride is selected from one or more of m-nitrobenzoyl chloride, p-nitrobenzoyl chloride, o-nitrobenzoyl chloride, 2,6-dimethyl-4-nitro-benzoyl chloride, 5-methyl-3-nitro-benzoyl chloride or 4,5-dimethyl-2-nitro-benzoyl chloride.

5. The preparation method according to claim 3, characterized in that, The aromatic diamine intermediate with polymethyl and amide bonds is selected from one or more of 1,3-bis(4-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(3-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(2,6-dimethyl-4-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(5-methyl-3-nitrobenzamido)-2,4,6-trimethylbenzene, 1,3-bis(4,5-dimethyl-2-nitrobenzamido)-2,4,6-trimethylbenzene, 1,4-bis(4-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(3-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(2-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(2,6-dimethyl-4-nitrobenzamido)-2,5-dimethylbenzene, 1,4-bis(5-methyl-3-nitrobenzamido)-2,5-dimethylbenzene or 1,4-bis(4,5-dimethyl-2-nitrobenzamido)-2,5-dimethylbenzene, 1,2-bis(4-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(3-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(2-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(2,6-dimethyl-4-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(5-methyl-3-nitrobenzamido)-4,5-dimethylbenzene, 1,2-bis(4,5-dimethyl-2-nitrobenzamido)-4,5-dimethylbenzene.

6. The preparation method according to claim 3, characterized in that, In step S1, the molar ratio of 2,4,6-trimethyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine or 4,5-dimethyl-1,2-phenylenediamine to nitrobenzoyl chloride is 1:2 to 1:2.

2.

7. The preparation method according to claim 3, characterized in that, In steps S1 and S2, the process of solution treatment is filtration, recrystallization, drying, recrystallization and redrying.

8. The preparation method according to claim 3, wherein The acid-binding agent is selected from one or several of quinoline, isoquinoline, pyridine, and triethylamine, and the molar amount of the acid-binding agent is 2 to 4 times the molar amount of 2,4,6-trimethyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine or 4,5-dimethyl-1,2-phenylenediamine.

9. The preparation method according to any one of claims 3-8, characterized in that, The reducing agent used in the catalytic reduction reaction is hydrazine hydrate, and the dosage of the reducing agent is 2 ml to 3 ml of hydrazine hydrate per 1 mmol of the aromatic diamine intermediate with polymethyl and amide bonds.

10. The preparation method according to any one of claims 3-8, characterized in that, The catalyst used in the catalytic reduction reaction is palladium / carbon, and the dosage of the catalyst is 0.02 to 0.05 g of palladium / carbon per 1 mmol of the aromatic diamine intermediate with polymethyl and amide bonds.

11. The preparation method according to any one of claims 3-8, characterized in that, In step S1, the reaction is carried out in an ice-water bath, and the reaction time is 6 to 12 h.

12. The preparation method according to any one of claims 3-8, characterized in that, In step S2, the temperature of the reaction system is 80 to 120 °C, and the reaction time is 6 to 12 h.

13. Use of an aromatic diamine intermediate having polymethyl and amide bonds as described in claim 1 or 2, or an aromatic diamine intermediate having polymethyl and amide bonds prepared by the preparation method described in any one of claims 3 - 12, in the preparation of a polymer for enhancing the glass transition temperature and transparency of a material.

14. Use of the aromatic diamine intermediate with polymethyl and amide bonds as claimed in claim 1 or 2, or the aromatic diamine intermediate with polymethyl and amide bonds prepared by the preparation method as claimed in any one of claims 3-12, in the preparation of polyamide high molecular polymers, polyimide high molecular polymers or urea high molecular polymers, characterized in that, The aromatic diamine intermediate having polymethyl and amide bonds reacts with a diacyl chloride to obtain a polyamide polymer material, the aromatic diamine intermediate having polymethyl and amide bonds reacts with a dianhydride to obtain a polyimide polymer material, and the aromatic diamine intermediate having polymethyl and amide bonds reacts with a diisocyanate to obtain a urea polymer material.

15. The application according to claim 14, wherein A method for preparing a polyimide polymer material, comprising the following steps: heating and reacting an aromatic diamine intermediate having polymethyl and amide bonds and a dianhydride monomer for synthesizing polyimide in an aprotic solvent to obtain polyamic acid, and then imidizing the polyamic acid to obtain a polyimide polymer.

16. The application according to claim 14, characterized in that A method for preparing a polyamide polymer material, comprising the following steps: heating and reacting an aromatic diamine intermediate having polymethyl and amide bonds and a diacyl chloride monomer for synthesizing polyamide in an aprotic solvent to obtain a polyamide resin, and then curing the polyamide resin to obtain a polyamide polymer.

17. The application according to claim 14, wherein A method for preparing a polyamide polymer, comprising the following steps: heating and reacting an aromatic diamine intermediate having polymethyl and amide bonds and a diisocyanate monomer for synthesizing polyamide in an aprotic solvent to obtain a polyurea resin, and then curing the polyurea resin to obtain a polyurea polymer.

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