A preparation method of α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene

Abstract

The present invention belongs to the technical field of organic synthesis, and relates to a method for preparing α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene. The method comprises: a compound of formula (I) is subjected to a wittig reaction to obtain a compound of formula (II); the compound of formula (II) is subjected to a coupling reaction to obtain a compound of formula (III); the compound of formula (III) is reacted with aniline to obtain a compound of formula (IV). The present invention uses 4-bromoacetophenone as a starting material to achieve the synthesis of the compound of formula (IV), and the synthetic route has the advantages of good selectivity, high yield, low danger, and easy availability of raw materials.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis and relates to a method for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene. Background Art

[0002] α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene is a material chemical intermediate product with excellent performance, and is also one of the important raw materials for synthesizing soluble polyimide. There are four methyl groups in the molecular structure of α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene, and its steric hindrance effect causes a torsion angle between the two benzene rings of biphenyl, resulting in a non-planar structure. Therefore, the polyimide film material with diamine monomer as the core synthesized with α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene as an intermediate has many special properties, such as good solubility, high mechanical strength and good light transmittance.

[0003] At present, there are few methods for synthesizing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene. The common method is to obtain the target structure by reacting 1,4-diisopropenylbenzene with aniline. The synthesis method of 1,4-diisopropenylbenzene is relatively complicated. It is usually obtained by peroxidation, reduction and dehydration of 1,4-diisopropylbenzene, or by bromination, hydrolysis and dehydration. The specific synthesis route is as follows:

[0004]

[0005] The above-mentioned α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene synthesis method has the disadvantages of high process requirements, many by-products, and difficult separation. In particular, the danger of oxygen leads to high requirements for equipment in the peroxidation process, which is not suitable for industrial production. Summary of the invention

[0006] The invention aims to solve the problems of high process requirements, many by-products and difficult separation of the current α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene.

[0007] Based on the above purpose, the present application solves this need in the field by providing an industrial preparation method of 3,3′,6,6′-tetramethoxy-2,2′-binaphthyl using 4-bromoacetophenone as a starting material.

[0008] On the one hand, the present invention relates to a method for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene, which comprises: subjecting a compound of formula (I) to a wittig reaction to obtain a compound of formula (II); subjecting the compound of formula (II) to a coupling reaction to obtain a compound of formula (III); and subjecting the compound of formula (III) to a reaction with aniline to obtain a compound of formula (IV); the structural formula is as follows:

[0009]

[0010] Furthermore, in the preparation method of α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene provided by the present invention, the synthesis method of the compound of formula (II) comprises: in the presence of bromomethyl triphenylphosphine and potassium tert-butoxide, reacting the compound of formula (I) to obtain the compound of formula (II).

[0011] Furthermore, in the method for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene provided by the present invention, the molar ratio of the compound of formula (I), methane triphenylphosphine and potassium tert-butoxide is 1:1.2-1.6:1.1-1.5.

[0012] Furthermore, in the preparation method of α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene provided by the present invention, the synthesis method of the compound of formula (III) comprises: preparing a Grignard reagent from the compound of formula (II) and magnesium, and adding acetone to the Grignard reagent to obtain the compound of formula (III).

[0013] Furthermore, in the method for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene provided by the present invention, the molar ratio of the compound of formula (II), magnesium and acetone is 1:1-2:1.1-3.

[0014] Furthermore, in the preparation method of α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene provided by the present invention, the synthesis method of the compound of formula (IV) comprises: reacting the compound of formula (III) and aniline with a catalyst containing a methyl oxadiazine group to obtain the compound of formula (IV).

[0015] Furthermore, in the method for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene provided by the present invention, the catalyst containing mesocyclic acid groups is selected from one of trifluoromethanesulfonic acid and methanesulfonic acid.

[0016] Furthermore, in the method for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene provided by the present invention, the molar ratio of the compound of formula (III), aniline and the catalyst containing the mexamic acid group is 1:4-20:0.2-2.

[0017] Compared with the prior art, the present invention has the following beneficial effects or advantages:

[0018] (1) The present invention uses 4-bromoacetophenone as a starting material to achieve the synthesis of α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene, and the synthetic raw materials are cheap and easily available.

[0019] (2) The reaction route provided by the present invention has mild process conditions, low equipment requirements, simple operation, and can meet production requirements using conventional reactors, making it suitable for large-scale industrial production.

[0020] (3) The reaction route provided by the present invention adopts conventional reaction, Wittig reaction and Grignard reaction, and has the advantages of good selectivity and high yield. The yield of the prepared α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene is as high as 50%.

[0021] (4) The intermediates and final products involved in the reaction route provided by the present invention are easy to separate and purify, and the process is simple. The intermediates do not require additional post-treatment and purification, and even the reaction solvent does not need to be removed by vacuum distillation. The final product, α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene, is precipitated from water by adjusting the pH value of its sulfate or hydrochloride and obtained by filtration. It is easy to operate and suitable for large-scale batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the LCMS spectrum of α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene synthesized in Example 1. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described below in conjunction with embodiments; however, the present invention is not limited to the following embodiments.

[0024] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0025] The experimental methods and detection methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0026] Example 1

[0027] This embodiment provides a method and process for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene.

[0028] (1) Synthesis of the compound of formula (II)

[0029] Under nitrogen protection, add 428.5g of bromomethyl triphenylphosphine and 398mL of THF to a three-necked flask, start stirring, cool to -10-0°C, add 123.2g of potassium tert-butoxide in batches (5min interval between each batch, divided into three batches), stir and react at -10-0°C for 3h after the addition is completed, then start to drop a solution of 199.0g of 4-bromoacetophenone and 398mL of THF. After the dropwise addition is completed, react at -10-0°C for 2h, then stop the reaction. Start atmospheric distillation to recover THF, and stop concentrating when the system temperature rises to 80°C. Add 1990 mL of n-heptane and 1990 mL of water to the concentrate, stir for 10 min, filter, let the filtrate stand, separate the aqueous phase, add 1990 mL of water to the organic phase, wash once, concentrate at normal pressure, pass through a column, and concentrate the column liquid to dryness under reduced pressure to obtain 189.2 g of a light yellow liquid with a 1-bromo-4-(1-propene-2-yl)benzene [compound of formula (II)] content of 98.5% and a yield of 96%.

[0030] (2) Synthesis of the compound of formula (III)

[0031] Preparation of Grignard reagent: Add 50 mL THF and 13.4 g magnesium powder to a three-necked flask under nitrogen protection, start stirring and heating. Reflux at 64°C for 10 min, dropwise add 1.0 g of compound (II) to initiate the reaction, and start dropping a solution of 99.0 g of compound (II) and 200 mL THF. After the addition is complete, reflux at 64°C for 1 h, and then stop the reaction.

[0032] Grignard coupling: Cool the prepared Grignard reaction solution to -10°C, start to drop 32.4g acetone, control the temperature at -10°C to 0°C, complete the dropwise addition, keep warm for 2h, and stop the reaction. Slowly pour the reaction system into a solution of 1L ice-water mixture and 70mL concentrated hydrochloric acid under stirring, add 600mL n-heptane water to wash until neutral. Start to concentrate the organic phase under reduced pressure (60-70°C) until no solvent flows out, weigh to obtain a yellow liquid: 78.7g, the content of the compound of formula (III) is 86.5%, and the yield is 88%.

[0033] (3) Synthesis of the compound of formula (IV)

[0034] Under nitrogen protection, 105.6g of aniline and 50.0g of the compound of formula (III) were added to a three-necked flask, stirring was started, 85.14g of trifluoromethanesulfonic acid was added dropwise, and the temperature was raised to 80°C after the addition was completed. After reacting at 80°C for 12h, the reaction was stopped. 150mL of dichloroethane was added to the system, and 5% sodium hydroxide solution was slowly added to neutralize the system, and then washed with water once. The obtained organic phase was concentrated under reduced pressure (50-60°C, -0.09Mpa) until no solvent flowed out, and then heated to 130°C-140°C to continue to concentrate under reduced pressure to recover aniline until no solvent flowed out, to obtain 97.0g of black liquid, to which 485mL of ethanol was added for recrystallization 3 times, to obtain 44.0g of white solid, α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene [compound of formula (IV)] content 99.%, yield 45%.

[0035] The obtained product was characterized by LCMS and NMR. Figure 1 This is the LCMS spectrum of the synthesized α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene. Figure 1 It can be seen that 345 in LCMS is the product Ms+1(H+) (target product molecular weight 344); the other fragments are M-(NH2)=329; M-(aniline)=252.

[0036] Example 2

[0037] This embodiment provides a method and process for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene.

[0038] (1) Synthesis of the compound of formula (II)

[0039] Under nitrogen protection, add 571.4g of bromomethyl triphenylphosphine and 995mL of THF to a three-necked flask, start stirring, raise the temperature to 10-20°C, add 168.0g of potassium tert-butoxide in batches (5min interval between each batch, divided into three batches), stir and react at 10-20°C for 3h after the addition is completed, raise the temperature to 40°C, and start dripping a solution of 199.0g of 4-bromoacetophenone and 995mL of THF. After the dripping is completed, react at 40°C for 1h, then stop the reaction. Start atmospheric distillation to recover THF, and stop concentrating when the system temperature rises to 80°C. To the concentrate, add 1990 mL of n-heptane and 1990 mL of water, stir for 10 min, filter, let the filtrate stand, separate the aqueous phase, add 1990 mL of water to the organic phase, wash once, concentrate at normal pressure, pass through a column, and concentrate the column liquid to dryness under reduced pressure to obtain 191.5 g of a light yellow liquid with a 1-bromo-4-(1-propene-2-yl)benzene [compound of formula (II)] content of 99.3% and a yield of 97.2%.

[0040] (2) Synthesis of the compound of formula (III)

[0041] Preparation of Grignard reagent: Add 100 mL of THF and 24.3 g of magnesium powder to a three-necked flask under nitrogen protection, start stirring and heating. Reflux at 64°C for 10 min, drop 1.0 g of compound (II) to initiate the reaction, cool to 10-20°C, and start dropping a solution of 99.0 g of compound (II) and 900 mL of THF. After the addition is complete, react at 10-20°C for 2 h, then stop the reaction.

[0042] Grignard coupling: Cool the prepared Grignard reaction solution to -10°C, start to drop 88.4g acetone, control the temperature at -10°C to 0°C, complete the dropwise addition, keep warm for 2h, and stop the reaction. Slowly pour the reaction system into a solution of 1L ice-water mixture and 280mL concentrated hydrochloric acid under stirring, add 600mL n-heptane and wash until neutral. Start to concentrate the organic phase under reduced pressure (60-70°C) until no solvent flows out, weigh to obtain a yellow liquid: 80.5g, the content of the compound of formula (III) is 87.2%, and the yield is 90%.

[0043] (3) Synthesis of the compound of formula (IV)

[0044] Under nitrogen protection, add 264.0g aniline and 50.0g compound of formula (III) to a three-necked flask, start stirring, drop 8.5g trifluoromethanesulfonic acid, heat to 160°C after the dropwise addition, react at 160°C for 2h, and then stop the reaction. Add 150mL dichloroethane to the system, slowly add 5% sodium hydroxide solution to neutralize the system, wash once with water, concentrate the obtained organic phase under reduced pressure (50-60°C, -0.09Mpa) until no solvent flows out, then heat to 130°C-140°C and continue to concentrate under reduced pressure to recover aniline until no solvent flows out, and obtain 95.4g black liquid, add 477mL ethanol to it for recrystallization 3 times, and obtain 48.8g white solid, α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene [compound of formula (IV)] content 99.5%, yield 50%.

[0045] Example 3

[0046] This embodiment provides a method and process for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene.

[0047] (1) Synthesis of the compound of formula (II)

[0048] Under nitrogen protection, add 571.4g of bromomethyl triphenylphosphine and 995mL of THF to a three-necked flask, start stirring, raise the temperature to 10-20°C, add 168.0g of potassium tert-butoxide in batches (5min interval between each batch, divided into three batches), stir and react at 10-20°C for 3h after the addition is completed, raise the temperature to 40°C, and start dripping a solution of 199.0g of 4-bromoacetophenone and 995mL of THF. After the dripping is completed, react at 40°C for 1h, then stop the reaction. Start atmospheric distillation to recover THF, and stop concentrating when the system temperature rises to 80°C. To the concentrate, add 1990 mL of n-heptane and 1990 mL of water, stir for 10 min, filter, let the filtrate stand, separate the aqueous phase, add 1990 mL of water to the organic phase, wash once, concentrate at normal pressure, pass through a column, and concentrate the column liquid to dryness under reduced pressure to obtain 191.5 g of a light yellow liquid with a 1-bromo-4-(1-propene-2-yl)benzene [compound of formula (II)] content of 99.3% and a yield of 97.2%.

[0049] (2) Synthesis of the compound of formula (III)

[0050] Preparation of Grignard reagent: Add 100 mL of THF and 24.3 g of magnesium powder to a three-necked flask under nitrogen protection, start stirring and heating. Reflux at 64°C for 10 min, drop 1.0 g of compound (II) to initiate the reaction, cool to 10-20°C, and start dropping a solution of 99.0 g of compound (II) and 900 mL of THF. After the addition is complete, react at 10-20°C for 2 h, then stop the reaction.

[0051] Grignard coupling: Cool the prepared Grignard reaction solution to -10°C, start to drop 88.4g acetone, control the temperature at -10°C to 0°C, complete the dropwise addition, keep warm for 2h, and stop the reaction. Slowly pour the reaction system into a solution of 1L ice-water mixture and 280mL concentrated hydrochloric acid under stirring, add 600mL n-heptane and wash until neutral. Start to concentrate the organic phase under reduced pressure (60-70°C) until no solvent flows out, weigh to obtain a yellow liquid: 79.6g, the content of the compound of formula (III) is 86.3%, and the yield is 89%.

[0052] (3) Synthesis of the compound of formula (IV)

[0053] Under nitrogen protection, 528.3g of aniline and 50.0g of the compound of formula (III) were added to a three-necked flask, stirring was started, 54.5g of methanesulfonic acid was added dropwise, and the temperature was raised to 160°C after the addition was complete. After reacting at 160°C for 2h, the reaction was stopped. 150mL of dichloroethane was added to the system, and 5% sodium hydroxide solution was slowly added to neutralize the system, and then washed with water once. The obtained organic phase was concentrated under reduced pressure (50-60°C, -0.09Mpa) until no solvent flowed out, and then heated to 130°C-140°C to continue to concentrate under reduced pressure to recover aniline until no solvent flowed out, to obtain 95.4g of black liquid, to which 477mL of ethanol was added for recrystallization 3 times, to obtain 46.3g of white solid, α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene [compound of formula (IV)] content of 99.5%, yield of 47.3%.

[0054] Example 4

[0055] This embodiment provides a method and process for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene.

[0056] (1) Synthesis of the compound of formula (II)

[0057] Under nitrogen protection, add 464.2g of bromomethyl triphenylphosphine and 398mL of THF to a three-necked flask, start stirring, raise the temperature to 10-20°C, add 145.5g of potassium tert-butoxide in batches (5min interval between each batch, divided into three batches), stir and react at 10-20°C for 3h after the addition is completed, cool to 10°C, and start to drop a solution of 199.0g of 4-bromoacetophenone and 398mL of THF. After the dropwise addition is completed, react at 10°C for 3h, then stop the reaction. Start atmospheric distillation to recover THF, and stop concentrating when the system temperature rises to 80°C. To the concentrate, add 1990 mL of n-heptane and 1990 mL of water, stir for 10 min, filter, let the filtrate stand, separate the aqueous phase, add 1990 mL of water to the organic phase, wash once, concentrate at normal pressure, pass through a column, and concentrate the column liquid to dryness under reduced pressure to obtain 190.2 g of a light yellow liquid with a 1-bromo-4-(1-propene-2-yl)benzene [compound of formula (II)] content of 99.3% and a yield of 96.5%.

[0058] (2) Synthesis of the compound of formula (III)

[0059] Preparation of Grignard reagent: Add 50 mL THF and 15.8 g magnesium powder to a three-necked flask under nitrogen protection, start stirring and heating. Reflux at 64°C for 10 min, dropwise add 1.0 g of compound (II) to initiate the reaction, dropwise add a solution of 99.0 g of compound (II) and 300 mL THF at reflux at 60-64°C. After the addition is complete, reflux at 64°C for 1 h, and then stop the reaction.

[0060] Grignard coupling: 88.4 g of acetone was added dropwise to the prepared Grignard reaction solution, and the temperature was controlled at 64°C. After the addition was complete, the reaction was kept warm for 2 hours and the reaction was stopped. The reaction system was slowly poured into a solution of 1 L of ice-water mixture and 280 mL of concentrated hydrochloric acid under stirring, and 600 mL of n-heptane was added to wash until neutral. The organic phase was concentrated under reduced pressure (60-70°C) until no solvent flowed out, and a yellow liquid was weighed to obtain 76.9 g, with a content of 88.1% of the compound of formula (III) and a yield of 86%.

[0061] (3) Synthesis of the compound of formula (IV)

[0062] Under nitrogen protection, 528.3g of aniline and 50.0g of the compound of formula (III) were added to a three-necked flask, stirring was started, 5.5g of methanesulfonic acid was added dropwise, and the temperature was raised to 140°C after the addition was complete. After reacting at 140°C for 12h, the reaction was stopped. 150mL of dichloroethane was added to the system, and 5% sodium hydroxide solution was slowly added to neutralize the system, and then washed with water once. The obtained organic phase was concentrated under reduced pressure (50-60°C, -0.09Mpa) until no solvent flowed out, and then heated to 130°C-140°C to continue to concentrate under reduced pressure to recover aniline until no solvent flowed out, to obtain 95.4g of black liquid, to which 477mL of ethanol was added for recrystallization 3 times, to obtain 45.0g of white solid, with a content of 99.6% of α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene [compound of formula (IV)] and a yield of 46.0%.

[0063] Example 5

[0064] This embodiment provides a method and process for preparing α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene.

[0065] (1) Synthesis of the compound of formula (II)

[0066] Under nitrogen protection, add 571.4g of bromomethyl triphenylphosphine and 995mL of THF to a three-necked flask, start stirring, raise the temperature to 10-20°C, add 168.0g of potassium tert-butoxide in batches (5min interval between each batch, divided into three batches), stir and react at 10-20°C for 3h after the addition is completed, raise the temperature to 40°C, and start dripping a solution of 199.0g of 4-bromoacetophenone and 995mL of THF. After the dripping is completed, react at 40°C for 1h, then stop the reaction. Start atmospheric distillation to recover THF, and stop concentrating when the system temperature rises to 80°C. To the concentrate, add 1990 mL of n-heptane and 1990 mL of water, stir for 10 min, filter, let the filtrate stand, separate the aqueous phase, add 1990 mL of water to the organic phase, wash once, concentrate at normal pressure, pass through a column, and concentrate the column liquid to dryness under reduced pressure to obtain 191.5 g of a light yellow liquid with a 1-bromo-4-(1-propene-2-yl)benzene [compound of formula (II)] content of 99.3% and a yield of 97.2%.

[0067] (2) Synthesis of the compound of formula (III)

[0068] Preparation of Grignard reagent: Add 100 mL of THF and 24.3 g of magnesium powder to a three-necked flask under nitrogen protection, start stirring and heating. Reflux at 64°C for 10 min, dropwise add 1.0 g of compound (II) to initiate the reaction, cool to 10-20°C, dropwise add a solution of 99.0 g of compound (II) and 900 mL of THF. After the addition is complete, react at 10-20°C for 2 h, then stop the reaction.

[0069] Grignard coupling: Cool the prepared Grignard reaction solution to 50°C, add 88.4g acetone dropwise, control the temperature at 40-50°C, complete the addition, keep warm for 2h, and stop the reaction. Slowly pour the reaction system into a solution of 1L ice-water mixture and 280mL concentrated hydrochloric acid under stirring, add 600mL n-heptane and wash until neutral. Start to concentrate the organic phase under reduced pressure (60-70°C) until no solvent flows out, weigh and obtain 82.2g of yellow liquid, with a content of 91.2% of the compound of formula (III) and a yield of 92%.

[0070] (3) Synthesis of the compound of formula (IV)

[0071] Under nitrogen protection, 528.3g of aniline and 50.0g of the compound of formula (III) were added to a three-necked flask, stirring was started, 5.5g of methanesulfonic acid was added dropwise, and the temperature was raised to 160°C after the addition was complete. After reacting at 160°C for 2h, the reaction was stopped. 150mL of dichloroethane was added to the system, and 5% sodium hydroxide solution was slowly added to neutralize the system, and then washed with water once. The obtained organic phase was concentrated under reduced pressure (50-60°C, -0.09Mpa) until no solvent flowed out, and then heated to 130°C-140°C to continue to concentrate under reduced pressure to recover aniline until no solvent flowed out, to obtain 95.4g of black liquid, to which 477mL of ethanol was added for recrystallization 3 times, to obtain 42.0g of white solid, α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene [compound of formula (IV)] content of 99.7%, yield of 43%.

[0072] As described above, the present invention can be well implemented. The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various changes and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the present invention.

Claims

1. A method for preparing α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, It is characterized in that include: The compound of formula (I) is subjected to a Wittig reaction to obtain a compound of formula (II); The compound of formula (II) undergoes coupling reaction to obtain the compound of formula (III); the compound of formula (III) reacts with aniline to obtain the compound of formula (IV); the structural formula is as follows: 、 、 、 ； The synthesis method of the compound of formula (II) comprises: reacting the compound of formula (I) in the presence of bromomethyl triphenylphosphine and potassium tert-butoxide to obtain the compound of formula (II); The synthesis method of the compound of formula (III) comprises: preparing a Grignard reagent from the compound of formula (II) and magnesium, and adding acetone to the Grignard reagent to obtain the compound of formula (III); The synthesis method of the compound of formula (IV) comprises: reacting the compound of formula (III) and aniline with a catalyst to obtain the compound of formula (IV); The catalyst is trifluoromethanesulfonic acid or methanesulfonic acid.

2. The method for preparing α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene according to claim 1, It is characterized in that In terms of molar ratio, the ratio of the compound of formula (I), methyl bromide triphenylphosphine salt and potassium tert-butoxide is 1:1.2-1.6:1.1-1.

5.

3. The method for preparing α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene according to claim 1, It is characterized in that In terms of molar ratio, the ratio of the compound of formula (II), magnesium and acetone is 1:1-2:1.1-3.

4. The method for preparing α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene according to claim 1, It is characterized in that In terms of molar ratio, the ratio of the compound of formula (III), aniline and the catalyst is 1:4-20:0.2-2.

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