阅读说明：本技术 一种含双三氟甲基苯取代不对称间位芳香二胺单体及其制备方法 (Bis-trifluoromethyl-benzene-substituted asymmetric meta-aromatic diamine monomer and preparation method thereof ) 是由 汪称意 郑慧 马燕 朱冠南 蒋彩荣 陶正旺 李坚 于 2020-12-11 设计创作，主要内容包括：本发明公开了一种含双三氟甲基苯取代不对称间位芳香二胺单体,具体为3,5-双(三氟甲基)苯基-2,4-二胺基苯,所含双三氟甲基均位于侧基苯环上；该单体合成方法简便,产率高,易于纯化,室温下稳定。其制备方法为：先将摩尔比为1:1的2,4-二硝基溴苯与3,5-双(三氟甲基)苯硼酸在碱性条件下反应得到中间体化合物3,5-双(三氟甲基)苯基-2,4-二硝基苯,然后通过还原反应,将中间体二硝基化合物还原得到相应的含双三氟甲基取代不对称间位芳香二胺单体3,5-双(三氟甲基)苯基-2,4-二胺基苯,该二胺单体可应用于高性能含氟聚酰亚胺膜材料的制备。(The invention discloses a bi-trifluoromethyl benzene substituted asymmetric meta-aromatic diamine monomer, in particular to 3, 5-bi (trifluoromethyl) phenyl-2, 4-diaminobenzene, wherein the bi-trifluoromethyl is positioned on a lateral group benzene ring; the monomer has simple synthesis method, high yield, easy purification and stability at room temperature. The preparation method comprises the following steps: the preparation method comprises the steps of firstly reacting 2, 4-dinitrobromobenzene with a molar ratio of 1:1 with 3, 5-bis (trifluoromethyl) phenylboronic acid under an alkaline condition to obtain an intermediate compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene, and then reducing the intermediate dinitrobenzene compound through a reduction reaction to obtain a corresponding 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene containing bis-trifluoromethyl substituted asymmetric meta-aromatic diamine monomer, wherein the diamine monomer can be applied to preparation of a high-performance fluorine-containing polyimide film material.)

1. A bis-trifluoromethyl-benzene-substituted asymmetric meta-aromatic diamine monomer is characterized in that: the aromatic diamine monomer is 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene, and the structural formula is as follows:

2. the bistrifluoromethylbenzene-substituted asymmetric meta-aromatic diamine-containing monomer of claim 1, wherein: the aromatic diamine monomer contains a bis (trifluoromethyl) benzene substituted asymmetric structure at the ortho position of the amino group, and the melting point is 160-163 ℃.

3. A method for preparing a monomer containing bis-trifluoromethylbenzene-substituted asymmetric meta-aromatic diamine as set forth in claim 1, wherein: comprises the following steps:

(1) under the protection of nitrogen, 2, 4-dinitrobromobenzene and 3, 5-bis (trifluoromethyl) phenylboronic acid with the molar ratio of 1:1 are added into a reaction vessel with mechanical stirring, a proper amount of organic solvent and a catalyst are further respectively added, the reaction is finished after the temperature is raised to 60-120 ℃ for 6-12 h after stirring for half an hour at room temperature, and a white intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene can be obtained after sedimentation, filtration, drying and recrystallization.

(2) Adding an intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene into a reaction vessel with mechanical stirring, further adding a proper amount of organic solvent, a reducing agent and a catalyst respectively, reacting for 4-12 h under reflux, ending the reaction, filtering while the reaction is hot, pouring the filtrate into a beaker, standing, performing suction filtration after a product is separated out, washing with ethanol, and performing vacuum drying to obtain a monomer 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene.

4. The method for preparing a bis (trifluoromethyl) benzene-substituted asymmetric meta-aromatic diamine-containing monomer according to claim 3, wherein the monomer is prepared by the following steps: in the step (1), the organic solvent is one of toluene and N-methylpyrrolidone, and the amount of the organic solvent is 2-4 times of the mass sum of 2, 4-dinitrobromobenzene and 3, 5-bis (trifluoromethyl) phenylboronic acid.

5. The method for preparing a bis (trifluoromethyl) benzene-substituted asymmetric meta-aromatic diamine-containing monomer according to claim 3, wherein the monomer is prepared by the following steps: in the step (1), the alkaline catalyst is one of potassium carbonate and sodium carbonate, and the dosage of the alkaline catalyst is 1-3 times of the mass of the 3, 5-bis (trifluoromethyl) phenylboronic acid.

6. The method for preparing a bis-trifluoromethylbenzene-substituted asymmetric meta-aromatic diamine monomer as claimed in claim 3, wherein: in the step (2), the organic solvent is ethanol, and the amount of the organic solvent is 10-15 times of the mass of the intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene.

7. The method for preparing a bis-trifluoromethylbenzene-substituted asymmetric meta-aromatic diamine monomer as claimed in claim 3, wherein: in the step (2), the reducing agent is hydrazine hydrate, and the using amount of the reducing agent is 4-8 times of the mass of the intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene.

8. The method for preparing a bis-trifluoromethylbenzene-substituted asymmetric meta-aromatic diamine monomer as claimed in claim 3, wherein: in the step (2), the catalyst is 5% or 10% Pd/C, and the amount of the catalyst is 0.05-0.1 time of the mass of the intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene.

Technical Field

The invention belongs to the field of preparation of aromatic diamine monomers, and particularly relates to an asymmetric meta-position aromatic diamine monomer containing bis (trifluoromethyl) benzene substitution and a preparation method thereof.

Background

Polyimide materials are special engineering materials with excellent mechanical properties and thermal stability, and have wide application in microelectronics and photoelectric industries as interlayer media, flexible circuit substrates and stress buffers. However, commercially available polyimide films generally exhibit relatively high dielectric constants (about 3.4 to 4.0 at 1 MHz), and are severely challenging to apply in miniaturized and lightweight electronic devices. In addition, due to the rigid macromolecular chains of polyimide, strong intermolecular force and close packing of the molecular chains, most of polyimide has high melting temperature and is insoluble in most of organic solvents, which brings difficulty to the molding processing of the polyimide. Therefore, the design and preparation of the polyimide film material with direct film coating and low dielectric constant have important significance.

Researches find that the bulk density and intermolecular force of a molecular chain can be reduced by introducing trifluoromethyl and a rigid non-coplanar structure into the molecular structure of polyimide, so that the solubility of the polyimide is effectively improved, and the dielectric constant is reduced. The aromatic diamine monomer containing the trifluoromethyl structure is a key monomer for preparing the high-performance polyimide film material, and aromatic nucleophilic substitution reaction is mostly adopted to synthesize the aromatic diamine monomer containing the trifluoromethyl structure in previous research reports, but the monomer prepared by the route usually contains a diether bond structure, and the introduction of the ether bond can obviously reduce the glass transition temperature of the polyimide, so that the monomer is not beneficial to microelectronic electric devices working in high-temperature environments.

Disclosure of Invention

The invention aims to solve the problems, 2, 4-dinitrobromobenzene and 3, 5-bis (trifluoromethyl) phenylboronic acid are used as starting materials, and a bis-trifluoromethyl benzene substituted asymmetric meta-position aromatic diamine monomer is successfully prepared through a convenient Suzuki coupling reaction, does not contain ether bonds, has high rigidity, and can keep the rigid structure of a molecular chain of the prepared polyimide. Meanwhile, the introduction of an asymmetric bis-trifluoromethyl benzene structure with larger free volume can further increase the free volume of the prepared polyimide, thereby effectively improving the solubility and dielectric properties of the polymer.

In order to realize the purpose, the invention is realized by the following technical scheme:

the monomer of the unsymmetrical meta-aromatic diamine containing bis (trifluoromethyl) benzene substitution is 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene, and the structural formula is as follows:

the bis (trifluoromethyl) benzene side group in the aromatic diamine monomer is positioned at the ortho position of the amino group, the melting point is 160-163 ℃, and the aromatic diamine monomer is white solid powder at normal temperature.

The preparation method of the monomer containing bis (trifluoromethyl) benzene substituted asymmetric meta-position aromatic diamine comprises the following steps:

(1) under the protection of nitrogen, 2, 4-dinitrobromobenzene and 3, 5-bis (trifluoromethyl) phenylboronic acid with the molar ratio of 1:1 are added into a three-neck flask with mechanical stirring, a proper amount of organic solvent and a catalyst are further added respectively, the mixture is stirred at room temperature for half an hour, then the temperature is raised to 60-120 ℃ for reaction for 6-12 hours, the reaction is finished, and a white intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene can be obtained after sedimentation, filtration, washing, drying and recrystallization.

(2) Adding an intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene into a three-neck flask with mechanical stirring, further adding a proper amount of organic solvent, a reducing agent and a catalyst respectively, reacting for 4-12 h under reflux, ending the reaction, filtering while the reaction is hot, pouring the filtrate into a beaker, standing, performing suction filtration after a product is separated out, washing with ethanol, and performing vacuum drying to obtain a monomer 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene.

The specific synthetic route of the bis-trifluoromethyl-benzene-substituted asymmetric meta-aromatic diamine monomer is as follows:

in the preparation method of the monomer containing the bis (trifluoromethyl) benzene substituted asymmetric meta-aromatic diamine, in the step (1), the organic solvent is one of toluene and N-methylpyrrolidone, and the dosage of the organic solvent is 2-4 times of the mass sum of 2, 4-dinitrobromobenzene and 3, 5-bis (trifluoromethyl) phenylboronic acid; the alkaline catalyst is one of potassium carbonate and sodium carbonate, and the dosage of the alkaline catalyst is 1-3 times of the mass of the 3, 5-bis (trifluoromethyl) phenylboronic acid.

In the preparation method of the monomer containing the bis (trifluoromethyl) benzene substituted asymmetric meta-aromatic diamine, in the step (2), the organic solvent is ethanol, and the amount of the organic solvent is 10-15 times of the mass of the intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene; the reducing agent is hydrazine hydrate, and the using amount of the reducing agent is 4-8 times of the mass of the intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene; the catalyst is 5% or 10% Pd/C, and the dosage of the catalyst is 0.05-0.1 time of the mass of the intermediate dinitro compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene.

The invention has the beneficial effects that:

(1) the bis-trifluoromethyl-benzene-substituted asymmetric meta-aromatic diamine monomer prepared by the invention has the advantages that the used starting raw materials are easy to obtain, the adopted synthetic route is relatively simple and convenient, the product is easy to purify and separate, the yield is high, and the stability is realized at normal temperature;

(2) the monomer containing bis (trifluoromethyl) benzene substituted asymmetric meta-aromatic diamine prepared by the invention can be further used for synthesizing and preparing high-performance polyimide film materials. The diamine structure does not contain ether bond, so that the high rigidity is realized, and the heat resistance of the polymer can be well maintained; meanwhile, due to the introduction of the large asymmetric bistrifluoromethylbenzene pendant group, the free volume of the polyimide can be further increased, and the bulk density of the polymer can be reduced, so that the dissolution film-forming property and the dielectric property of the prepared polyimide can be improved better.

Drawings

FIG. 1 shows the structure of 3, 5-bis (trifluoromethyl) in example 1) Process for preparing phenyl-2, 4-dinitrobenzene¹H NMR spectrum.

FIG. 2 is a drawing showing the reaction scheme of 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene in example 1¹H NMR spectrum.

FIG. 3 is a drawing showing the reaction scheme of 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene in example 1¹³C NMR spectrum.

FIG. 4 is an infrared spectrum of 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene and 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene in example 1.

Detailed Description

Example 1

Preparation of monomer containing bis (trifluoromethyl) benzene substituted asymmetric meta-aromatic diamine

(1) Under the protection of nitrogen, 21.74g (88mmol) of 2, 4-dinitrobromobenzene, 22.70g (88mmol) of 3, 5-bis (trifluoromethyl) phenylboronic acid, 1.85g (0.2mmol) of tetrakis (triphenylphosphine) palladium, 150mL of a mixed solvent of 2:1 toluene and ethylene glycol dimethyl ether in volume ratio and 120mL of a 1mol/L sodium carbonate solution are respectively added into a 500mL three-neck flask, stirring at room temperature for half an hour, heating to 100 deg.C, reacting for 10 hr, cooling to room temperature, precipitation in water, suction filtration, drying and further recrystallization gave the intermediate compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene in 83% yield (here yield is given by the ratio of the mass of the intermediate compound actually obtained to the mass of the intermediate compound theoretically obtained).¹H NMR(DMSO-d₆400MHz) as shown in figure 1; FT-IR (KBr) is shown in FIG. 4.

(2) Respectively adding 18.82g (0.05mol) of an intermediate compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene, 180mL of ethanol, 12.01g (0.3mol) of hydrazine hydrate reducing agent and 0.95g of 5% solid content Pd/C catalyst into a three-neck flask provided with a stirrer and a spherical condenser, reacting for 6 hours under reflux, finishing the reaction and filtering the mixture while the mixture is hot, pouring the filtrate into a beaker, standing the filtrate, leaching and washing the product with ethanol after the product is separated out, and drying the product in vacuum to obtain white crystalline 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene, wherein the yield is 82% (the yield is the ratio of the mass of the actually obtained diamine monomer to the mass of the theoretically obtained diamine monomer)Value obtained)¹H NMR(DMSO-d₆400MHz) as shown in figure 2;¹³C NMR(DMSO-d₆400MHz) as shown in figure 3; FT-IR (KBr) is shown in FIG. 4.

Example 2

Preparation of monomer containing bis (trifluoromethyl) benzene substituted asymmetric meta-aromatic diamine

(1) Under nitrogen protection, 21.74g (88mmol) of 2, 4-dinitrobromobenzene, 22.70g (88mmol) of 3, 5-bis (trifluoromethyl) phenylboronic acid, 1.85g (0.2mmol) of tetrakis (triphenylphosphine) palladium were charged into a 1000mL three-necked flask, respectively adding 320mL of mixed solvent of toluene and ethylene glycol dimethyl ether with the volume ratio of 3:1 and 200mL of sodium carbonate solution with the concentration of 1.5mol/L, stirring for half an hour at room temperature, heating to 105 ℃, reacting for 8 hours, cooling to room temperature after the reaction is finished, precipitation in water, suction filtration, drying and further recrystallization give the intermediate compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene in 85% yield (the yield here being obtained from the ratio of the mass of the intermediate compound actually obtained to the mass of the intermediate compound theoretically obtained).

(2) 18.82g (0.05mol) of intermediate compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene is added into a three-neck flask provided with a stirrer and a spherical condenser, 200mL of ethanol, 15.01g (0.3mol) of hydrazine hydrate reducing agent and 1.51g of 5% solid content Pd/C catalyst are respectively added for reaction under reflux for 10 hours, the reaction is finished and filtered while hot, the filtrate is poured into a beaker, and is placed still, after the product is precipitated, the product is filtered, washed by ethanol and dried in vacuum to obtain white crystal-shaped 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene, and the yield is 84% (the yield is obtained by the ratio of the mass of the actually obtained diamine monomer to the mass of the theoretically obtained diamine monomer).

Example 3

Preparation of monomer containing bis (trifluoromethyl) benzene substituted asymmetric meta-aromatic diamine

(1) Under nitrogen protection, 21.74g (88mmol) of 2, 4-dinitrobromobenzene, 22.70g (88mmol) of 3, 5-bis (trifluoromethyl) phenylboronic acid, 1.85g (0.2mmol) of tetrakis (triphenylphosphine) palladium were charged into a 1000mL three-necked flask, respectively adding 650mL of mixed solvent of toluene and ethylene glycol dimethyl ether with the volume ratio of 4:1 and 240mL of sodium carbonate solution with the concentration of 2mol/L, stirring for half an hour at room temperature, heating to 110 ℃, reacting for 7 hours, cooling to room temperature after the reaction is finished, precipitation in water, suction filtration, drying and further recrystallization gave the intermediate compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene in 82% yield (here yield is given by the ratio of the mass of the intermediate compound actually obtained to the mass of the intermediate compound theoretically obtained).

(2) 18.82g (0.05mol) of intermediate compound 3, 5-bis (trifluoromethyl) phenyl-2, 4-dinitrobenzene is added into a three-neck flask provided with a stirrer and a spherical condenser tube, 250mL of ethanol, 18.01g (0.4mol) of hydrazine hydrate reducing agent and 1.88g of 10% solid content Pd/C catalyst are respectively added for reaction under reflux for 8 hours, the reaction is finished and the mixture is filtered while hot, the filtrate is poured into a beaker, and is kept stand, after the product is separated out, the filtrate is filtered, washed by ethanol and dried in vacuum to obtain white crystal-shaped 3, 5-bis (trifluoromethyl) phenyl-2, 4-diaminobenzene, and the yield is 81% (the yield is obtained by the ratio of the mass of the actually obtained diamine monomer to the mass of the theoretically obtained diamine monomer).

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