Synthesis method of N,N’-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane

Abstract

The invention discloses a synthesis method of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, which comprises reacting 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane with maleic anhydride to obtain a mixture of intermediate I and intermediate II; dehydrating and cyclizing the mixture in the presence of a basic catalyst and acetic anhydride to obtain a reaction solution; removing impurities by using a basic reagent and crystallizing with toluene to obtain N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane. The method of the invention uses a basic reagent to remove impurities after the dehydration and cyclization reaction, so as to obtain a product purity of more than 99%. Ethyl acetate is used as the reaction solvent, which is easy to recycle and reuse, not only greatly reducing the difficulty of wastewater treatment, but also effectively reducing the production cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a method for synthesizing N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane. Background Art

[0002] Bismaleimide (abbreviated as BMI) is another resin system derived from polyimide resin systems. It is a bifunctional compound with maleimide as the active end group, and has excellent heat resistance, weather resistance, electrical insulation, wave transmission, radiation resistance, flame retardancy, good mechanical properties and dimensional stability. It has fluidity, moldability and molding processability similar to those of epoxy resins, and overcomes the disadvantage of relatively low heat resistance of epoxy resins. Therefore, it has been rapidly developed and widely used in recent years. As one of the high-performance polymers with high strength, high modulus and relatively low density, BMI is widely used in industrial fields such as aviation, aerospace, machinery, electronics, transportation, etc., as the resin matrix of advanced composite materials, high-temperature insulation materials and adhesives, etc.

[0003] N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane is a new type of bismaleimide resin monomer, a brown solid, with the molecular formula: C 26 H 22 O4N2, relative molecular weight: 426.47. Since it is a mixture of two-component isomers, it has the characteristics of low melting point, strong moldability and easy processing and forming. Moreover, because its structure contains 6 primary, secondary and tertiary carbons, compared with bismaleimide resin monomers with other structures, it has better solubility in general solvents, higher reaction activity with aromatic amines, and the materials prepared have excellent toughness, moisture resistance and stability.

[0004] Currently, no literature reports on the synthesis of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane have been found. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide a method for synthesizing N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane with relatively high purity.

[0006] The technical solution for achieving the purpose of the present invention is: a method for synthesizing N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, which has the following steps:

[0007] ① 5(6)-Amino-1-(4-aminophenyl)-1,3,3-trimethylindane reacts with maleic anhydride in ethyl acetate to obtain a mixture of intermediate I and intermediate II;

[0008] ② The mixture of intermediate I and intermediate II obtained in step ① undergoes a dehydration ring-closure reaction in ethyl acetate in the presence of a basic catalyst and acetic anhydride to obtain a reaction solution containing N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane;

[0009] ③ The reaction solution obtained in step ② is treated with a basic reagent to remove impurities, and then crystallized with toluene to obtain N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane.

[0010] The reaction temperature of the above step ① is 5 - 50 °C.

[0011] In the above step ①, the 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane is a mixture of two isomers, 5-amino-1-(4-aminophenyl)-1,3,3-trimethylindane and 6-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, and their molar ratio is 1:0.6 - 1:1.5.

[0012] In the above step ①, the molar ratio of the 5(6)-amino-1-(4'-aminophenyl)-1,3,3-trimethylindane to the maleic anhydride is 1:2 - 1:5, preferably 1:2.5 - 1:3.

[0013] In the mixture of intermediate I and intermediate II obtained in the above step ①, the molar ratio of intermediate I to intermediate II is 1:0.6 - 1:1.5.

[0014] The structural formula of intermediate I is: .

[0015] The structural formula of intermediate II is: .

[0016] The dehydration ring-closure reaction temperature of the above step ② is 30 - 50 °C.

[0017] In the above step ②, the molar ratio of the mixture of intermediate I and intermediate II to the acetic anhydride is 1:3 - 1:8.

[0018] In the above step ②, the basic catalyst is triethylamine, pyridine, N,N - diisopropylethylamine or DMAP; the molar ratio of the mixture of intermediate Ⅰ and intermediate Ⅱ to the basic catalyst is 1:0.2 to 1:3, preferably 1:0.7 to 1:2.6.

[0019] In the above step ③, the reaction temperature for removing impurities is 70 - 75 °C.

[0020] In the above step ③, the basic reagent is triethylamine, pyridine, N,N - diisopropylethylamine or DMAP; the molar ratio of the mixture of intermediate Ⅰ and intermediate Ⅱ to the basic reagent is 1:0.5 to 1:4, preferably 1:1 to 1:2.5.

[0021] In the above step ③, the structure of the impurity is as follows:

[0022] 、 、 、 。

[0023] The N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane obtained in the above step ③ is a mixture of two isomers, N,N'-bis(maleimidyl)-5-amino-1-(4-aminophenyl)-1,3,3-trimethylindane and N,N'-bis(maleimidyl)-6-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, and their molar ratio is 1:0.6 to 1:1.5.

[0024] Among them: The structural formula of N,N'-bis(maleimidyl)-5-amino-1-(4-aminophenyl)-1,3,3-trimethylindane (CAS No. 123811-63-2) is as follows:

[0025] 。

[0026] The structural formula of N,N'-bis(maleimidyl)-6-amino-1-(4-aminophenyl)-1,3,3-trimethylindane (CAS No. 958832-00-3) is as follows:

[0027] 。

[0028] The positive effects of the present invention are as follows:

[0029] (1) By using a basic reagent to remove impurities after the dehydration and cyclization reaction in the method of the present invention, a product purity of more than 99% can be obtained.

[0030] (2) The method of the present invention uses ethyl acetate as the reaction solvent, which is easy to recycle and reuse. This not only greatly reduces the difficulty of wastewater treatment but also effectively reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the liquid chromatogram of the mixture of intermediate I and intermediate II prepared in step ① of Example 1.

[0032] Figure 2 It is the mass spectrum of the mixture of intermediate I and intermediate II prepared in step ① of Example 1.

[0033] Figure 3 It is the mass spectrum of the impurity obtained in step ② of Example 1.

[0034] Figure 4 It is the liquid chromatogram of the target product obtained in Example 1.

[0035] Figure 5 It is the mass spectrum of the target product obtained in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0036] (Example 1)

[0037] The synthesis method of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane in this example has the following steps:

[0038] ① Add 200 g of ethyl acetate and 110.5 g of maleic anhydride (1.13 mol) to a 500 mL three-necked flask, and stir to dissolve to obtain a maleic anhydride ethyl acetate solution.

[0039] Under stirring, add 400 g of ethyl acetate and 100 g of 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane (0.38 mol, equimolar isomers) to a 1 L three-necked flask, cool down to 0 - 5 °C, and dropwise add the above-mentioned maleic anhydride ethyl acetate solution. During the dropping process, control the temperature at 3 - 15 °C. After dropping, first stir and react at a temperature of 18 ± 2 °C for 30 min, and then raise the temperature to 43 ± 2 °C and stir and react for 30 min.

[0040] After the reaction is completed, slowly cool down to 33 ± 2 °C (the cooling takes about 1.5 h), a large amount of granular solid precipitates, continue to stir for 1 h until the crystallization is complete, and finally cool down to 22 ± 2 °C and stir for 2 h. Filter, wash the filter cake with 100 g of ethyl acetate, and dry it at 40 - 45 °C under forced air until constant weight to obtain 160.8 g of a mixture of yellow-green granular intermediate I and intermediate II, with a purity of 99.6% and a yield of 92.6%.

[0041] The liquid chromatogram of this mixture is shown inFigure 1 , see the mass spectrometry chart in Figure 2 .

[0042] ② Add 700 g of ethyl acetate and 83.9 g of acetic anhydride (0.82 mol) successively into a 2 L three-necked flask. While stirring, slowly add 100 g (0.22 mol) of the mixture of intermediate I and intermediate II obtained in step ①. After adding, stir at 20 - 25 °C for 30 min, then dropwise add 56.0 g of triethylamine (0.55 mol) while stirring. Control the temperature at 22 - 33 °C during the dropping process. After dropping, stir at 35 - 40 °C for 8 h. Take a sample for HPLC in-process control: the peak area of the target product + the peak area of impurities ≥ 98%. See the mass spectrometry chart of the impurities in Figure 3 .

[0043] ③ After the reaction is completed, cool down to 5 - 15 °C, and dropwise add 580 g of 15 wt% Na2CO3 aqueous solution. Control the temperature < 25 °C during the dropping process. After dropping, continue to stir for 1 h, let it stand for liquid separation. The upper organic layer is washed with 100 g of purified water, then transferred to a 2 L three-necked flask. While stirring, add 50 g of triethylamine (0.50 mol), and stir and heat up to 70 - 75 °C for reaction for 6 h.

[0044] After the reaction is completed, cool down to 20 - 25 °C, add 150 g of purified water, stir for 30 min, let it stand for liquid separation. The upper organic layer is concentrated to dryness under vacuum at 45 - 90 °C. While stirring, dropwise add 580 g of toluene to the concentrated solution. Control the temperature at 90 - 100 °C during the dropping process. After dropping, slowly cool down to 66 - 70 °C, and stir at this temperature for 1.5 h. A large amount of solid precipitates. Continue to cool down to 5 - 10 °C, filter. The filter cake is rinsed with 100 g of ice-cold toluene, and toluene is recovered by distillation. The wet product is dried under vacuum at 80 - 85 °C for 14 h to obtain 80.1 g of the brown target product, with a purity of 99.2% and a yield of 86.9% [calculated based on the mixture of intermediate I and intermediate II in step ②].

[0045] See the liquid chromatography chart of the target product in Figure 4 , see the mass spectrometry chart in Figure 5 .

[0046] (Example 2)

[0047] The synthesis method of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane in this example has the following steps:

[0048] ① Add 200 g of ethyl acetate and 110.5 g of maleic anhydride (1.13 mol) into a 500 mL three-necked flask, and stir to dissolve to obtain a maleic anhydride ethyl acetate solution.

[0049] Under stirring, 550 g of ethyl acetate and 120 g of 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane (0.45 mol) were added to a 2 L three-necked flask. The temperature was lowered to 0 - 5 °C, and the above-mentioned maleic anhydride ethyl acetate solution was added dropwise. During the dropping process, the temperature was controlled at 2 - 13 °C. After the dropping was completed, the mixture was stirred and reacted at 20 ± 2 °C for 30 min, and then the temperature was raised to 45 ± 2 °C and stirred and reacted for 35 min.

[0050] After the reaction was completed, the temperature was slowly lowered to 33 ± 2 °C (the temperature reduction took about 1 h), and a large amount of granular solids were precipitated. Stirring was continued for 1 h until crystallization was complete. Finally, the temperature was lowered to 21 ± 2 °C and stirred for 2 h. Then, filtration was carried out. The filter cake was rinsed with 90 g of ethyl acetate and dried to constant weight at 40 - 45 °C under forced air drying, obtaining 196.7 g of a mixture of intermediate Ⅰ and intermediate Ⅱ in the form of yellow-green granules, with a purity of 99.1% and a yield of 94.4%.

[0051] ② 1050 g of ethyl acetate and 172.2 g of acetic anhydride (1.69 mol) were successively added to a 3 L three-necked flask. Under stirring, 150 g (0.32 mol) of the mixture of intermediate Ⅰ and intermediate Ⅱ obtained in step ① was slowly added. After addition, the mixture was stirred at 20 - 25 °C for 30 min, and then 26.3 g of triethylamine (0.26 mol) was added dropwise under stirring. During the dropping process, the temperature was controlled at 21 - 28 °C. After the dropping was completed, the mixture was stirred at 35 - 40 °C for 9 h. Sampling was carried out for HPLC control: the peak area of the target product + the peak area of impurities ≥ 98%.

[0052] ③ After the reaction was completed, the temperature was lowered to 5 - 9 °C, and 1190 g of 15 wt% aqueous Na2CO3 solution was added dropwise. During the dropping process, the temperature was controlled at < 25 °C. After the dropping was completed, stirring was continued for 1 h, and then it was left to stand for liquid separation. The upper organic layer was washed with 150 g of purified water and then transferred to a 3 L three-necked flask. 45 g of triethylamine (0.45 mol) was added under stirring, and the temperature was raised to 70 - 75 °C and reacted for 5 h.

[0053] After the reaction was completed, the temperature was lowered to 20 - 25 °C, 220 g of purified water was added, and the mixture was stirred for 30 min and then left to stand for liquid separation. The upper organic layer was concentrated to dryness under vacuum at 45 - 90 °C. Under stirring, 850 g of toluene was added dropwise to the concentrated solution. During the dropping process, the temperature was controlled at 92 - 102 °C. After the dropping was completed, the temperature was slowly lowered to 63 - 66 °C, and the mixture was stirred at this temperature for 2 h, during which a large amount of solids were precipitated. The temperature was further lowered to 3 - 8 °C, and filtration was carried out. The filter cake was rinsed with 150 g of ice-cold toluene, and toluene was recovered by distillation. The wet product was dried under vacuum at 80 - 85 °C for 16 h, obtaining 122.1 g of the brown target product, with a purity of 99.4% and a yield of 88.3% [calculated based on the mixture of intermediate Ⅰ and intermediate Ⅱ in step ②].

Claims

1. A method for synthesizing N,N'-bis(maleimido)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, comprising the following steps: ① React 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane with maleic anhydride in ethyl acetate to obtain a mixture of intermediate Ⅰ and intermediate Ⅱ; ② In the presence of a basic catalyst and acetic anhydride, the mixture of intermediate Ⅰ and intermediate Ⅱ obtained in step ① undergoes a dehydration cyclization reaction in ethyl acetate to obtain a reaction solution containing N,N'-bis(maleimido)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane; the temperature of the dehydration cyclization reaction is 30 - 50 °C; ③ Use a basic reagent to remove impurities from the reaction solution obtained in step ②, and then crystallize with toluene to obtain N,N'-bis(maleimido)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane; the reaction temperature for removing impurities is 70 - 75 °C.

2. The synthesis method of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane according to claim 1, characterized in that: In the above step ③, the basic reagent is triethylamine, pyridine, N,N-diisopropylethylamine or DMAP; the molar ratio of the mixture of intermediate Ⅰ and intermediate Ⅱ to the basic reagent is 1∶0.5 - 1∶4.

3. The synthesis method of N,N’-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane according to claim 2, characterized in that: The reaction temperature of the above step ① is 5 - 50 °C.

4. The synthesis method of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane according to claim 2, characterized in that: In the above step ①, the molar ratio of 5(6)-amino-1-(4'-aminophenyl)-1,3,3-trimethylindane to maleic anhydride is 1∶2 - 1∶5.

5. The synthesis method of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane according to claim 2, characterized in that: In the above step ②, the molar ratio of the mixture of intermediate Ⅰ and intermediate Ⅱ to acetic anhydride is 1∶3 - 1∶8.

6. The synthesis method of N,N'-bis(maleimidyl)-5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane according to claim 2, characterized in that: In the above step ②, the basic catalyst is triethylamine, pyridine, N,N-diisopropylethylamine or DMAP; the molar ratio of the mixture of intermediate Ⅰ and intermediate Ⅱ to the basic catalyst is 1∶0.2 - 1∶3.

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