Preparation method of 1,3-bis(4-aminophenoxy)benzene

Abstract

The present invention provides a method for preparing 1,3-bis(4-aminophenoxy)benzene, which comprises the following steps: S1: Under nitrogen protection, resorcinol, p-chloronitrobenzene, and a catalyst are added to a solvent for reaction; S2: After the reaction is completed, the temperature is lowered, hydrogen is introduced for continuous reaction, and after the reaction is completed, post-treatment is carried out to obtain 1,3-bis(4-aminophenoxy)benzene. The beneficial effects of the present invention are as follows: The preparation method of the present invention uses a new process system, with two-step joint feeding, safe operation, high quality of the synthesized product, and is suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 1,3-bis(4-aminophenoxy)benzene. Background Art

[0002] Polyimide (PI) is a high molecular material with an imide ring in its main chain. Due to its unique structure, it has excellent comprehensive properties and is at the forefront of high molecular materials. PI has been widely used in flexible displays, aerospace, electrical insulation, microelectronics, batteries, photoresists and other fields.

[0003] Aromatic polyimide contains a rigid imide ring and benzene ring, making it have more excellent thermal stability, mechanical properties and thermal stability. 1,3-Bis(4-aminophenoxy)benzene is an important polyimide monomer, and the polyimide synthesized by using it has broad application prospects.

[0004] Currently, the common synthesis methods are mainly two-step reactions. 1,3-Bis(4-nitrophenoxy)benzene is synthesized by the coupling reaction of resorcinol and p-chloronitrobenzene; the nitro compound is reduced to synthesize 1,3-bis(4-aminophenoxy)benzene. The first-step coupling reaction process usually adopts inorganic base-high temperature conditions, and the second-step reduction reaction mainly has reduction methods such as palladium-carbon-hydrogen, palladium-carbon-hydrazine hydrate, iron powder-hydrochloric acid and other systems. Both steps have certain drawbacks. For example, the first step will produce a large amount of solid waste and consume a large amount of energy; the second step uses palladium-carbon as a catalyst, which is relatively expensive and has a high cost; the reduction of the iron powder-hydrochloric acid system produces a large amount of three wastes, and the quality of the synthesized product is poor. Summary of the Invention

[0005] In view of this, the present invention aims to provide a preparation method of 1,3-bis(4-aminophenoxy)benzene with simple process, low production cost, green environmental protection, high product quality and yield, and suitable for large-scale production.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A preparation method of 1,3-bis(4-aminophenoxy)benzene, comprising the following steps:

[0008] S1: Under the action of a protective gas, resorcinol, p-chloronitrobenzene and a catalyst are added to a solvent for reaction;

[0009] S2: After the reaction is completed, the temperature is lowered, hydrogen is introduced and the reaction continues. After the reaction is completed, post-treatment is carried out to obtain 1,3-bis(4-aminophenoxy)benzene.

[0010] Further, in the step S1, the mass ratio of the catalyst to resorcinol is 0.1-0.4:1.

[0011] Further, the post-treatment in step S2 includes filtering to remove the catalyst, adding a poor solvent, reducing the temperature, precipitating a white solid, and drying the solid to obtain 1,3-bis(4-aminophenoxy)benzene.

[0012] Further, the molar ratio of the solvent, poor solvent, p-chloronitrobenzene, and resorcinol is 50 - 80:40 - 60:2 - 2.2:1;

[0013] Preferably, the protective gas in step S1 is an inert gas, and the inert gas is nitrogen;

[0014] Preferably, the solvent is a poor solvent. More preferably, the solvent includes one or more of methanol, ethanol, water, and acetonitrile. Most preferably, the solvent is ethanol.

[0015] Further, the reaction temperature in step S1 is 60 - 90 °C;

[0016] The temperature reduction temperature in step S2 is 50 - 80 °C.

[0017] The solvent in step S1 includes one or more of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide. Preferably, the solvent is dimethylformamide.

[0018] For the preparation method of 1,3-bis(4-aminophenoxy)benzene described in claim 1, the preparation method of the catalyst includes the following steps:

[0019] A1: Put the molecular sieve into an aqueous solution of palladium chloride and stir at room temperature to obtain a pretreated molecular sieve;

[0020] A2: Dissolve imidazole in ethanol, add sodium hydroxide to react, reduce the temperature to room temperature, add tetrabutylammonium bromide and continue to reflux, filter the solid, add the pretreated molecular sieve thereto, stir at room temperature, introduce hydrogen and continue to react, evaporate ethanol under normal pressure to obtain a white solid, and the solid is the catalyst.

[0021] Further, the molecular sieve in step A1 is one or more of SBA-15 molecular sieve, SBA-16, and MCM-41;

[0022] Preferably, the palladium chloride in step A1 is palladium dichloride;

[0023] Preferably, the concentration of the aqueous solution of palladium chloride is 0.5 - 1.2 g / L.

[0024] Preferably, the hydrogen pressure in step A2 is 0.1 - 0.3 MPa.

[0025] Further, in the step A2, the molar ratio of ethanol, tetrabutylammonium bromide, sodium hydroxide, and imidazole is 60 - 90:1 - 1.2:1.1 - 1.3:1.

[0026] Further, the mass ratio of palladium chloride, imidazole, and the catalyst is 0.01 - 0.05:0.1 - 0.3:1; preferably, tetrabutylammonium bromide is added and refluxed for 6 - 10 h.

[0027] Preferably, after adding the pretreated molecular sieve, it is slowly stirred at room temperature for 4 - 9 h, hydrogen is introduced and the reaction continues for 2 - 5 h, ethanol is evaporated at normal pressure to obtain a white solid, and the solid is vacuum - dried at 60 - 80 °C for 10 - 15 h to obtain the catalyst.

[0028] Compared with the prior art, the preparation method of 1,3 - bis(4 - aminophenoxy)benzene of the present invention has the following advantages:

[0029] The preparation method of the present invention uses a new process system, which is simple to prepare, safe to operate, has little environmental pollution, has a high yield and high purity of the synthesized product, and is suitable for large - scale production.

[0030] The catalyst can be reused repeatedly and the production cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0032] Figure 1 is the synthesis route diagram of 1,3 - bis(4 - aminophenoxy)benzene prepared in Example 1 of the present invention;

[0033] Figure 2 is the HPLC diagram of 1,3 - bis(4 - aminophenoxy)benzene prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0035] The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0036] Example 1

[0037] (I) Preparation of GDX - 3 (catalyst)

[0038] Put 10 g of SBA-15 into 300 mL of deionized aqueous solution of palladium dichloride at 1 g / L, stir at room temperature for 24 h, filter it, and collect the solid for use. Add 2 g of imidazole and 1.41 g of sodium hydroxide to 108 g of ethanol, reflux for 50 min. Cool to room temperature, add 9.94 g of tetrabutylammonium bromide, continue to reflux for 8 h, and a large amount of white solid precipitates. Filter to remove the solid. Add the treated SBA-15 to the filtrate, stir slowly at room temperature for 6 h, introduce 0.2 MPa of hydrogen, and continue the reaction for 5 h. After the reaction, evaporate the solution to dryness at normal pressure at 80 °C, and dry the white solid in vacuo at 70 °C for 12 h to obtain 17.3 g of catalyst GDX-3.

[0039] (II) Synthesis of 1,3-bis(4-aminophenoxy)benzene

[0040] Add 10 g of resorcinol, 30.1 g of p-chloronitrobenzene, and 2.5 g of GDX-3 to 495 g of dimethylformamide, stir evenly, heat up to 80 °C, and react for 8 h. After the reaction, cool to 60 °C, introduce hydrogen, keep the pressure at 1.2 MPa, and keep the temperature for 6 h. After the reaction, filter to remove GDX-3, add 210 g of ethanol to the filtrate, cool the temperature to -5 °C, and a large amount of white solid precipitates. Dry the solid in vacuo at 100 °C for 12 h to obtain 25.84 g of 1,3-bis(4-aminophenoxy)benzene, with a molar yield of 97.34%, a purity of 99.99%, YI = 0.43, and the total metal ion content <= 100 ppb.

[0041] Example 2

[0042] Add 10 g of resorcinol, 28.6 g of p-chloronitrobenzene, and 1 g of GDX-3 (GDX-3 prepared in Example 1) to 396 g of dimethylacetamide, stir evenly, heat up to 60 °C, and react for 6 h. After the reaction, cool to 50 °C, introduce hydrogen, keep the pressure at 0.8 MPa, and keep the temperature for 5 h. After the reaction, filter to remove GDX-3, add 116 g of methanol to the filtrate, cool the temperature to -10 °C, and a large amount of white solid precipitates. Dry the solid in vacuo at 100 °C for 12 h to obtain 25.38 g of 1,3-bis(4-aminophenoxy)benzene, with a molar yield of 95.61%, a purity of 99.96%, YI = 0.54, and the total metal ion content < 100 ppb.

[0043] Example 3

[0044] 10 g of resorcinol, 31.4 g of p-chloronitrobenzene, and 4 g of GDX-3 (GDX-3 prepared in Example 1) were added to 530 g of N-methylpyrrole. After stirring evenly, the temperature was raised to 90 °C and the reaction was carried out for 10 h. After the reaction was completed, the temperature was lowered to 70 °C, hydrogen was introduced, and the pressure was maintained at 1.5 MPa. The reaction was carried out under insulation for 7 h. After the reaction was completed, GDX-3 was removed by filtration. 95 g of deionized water was added to the filtrate, and the temperature was lowered to 0 °C. A large amount of white solid precipitated out. The solid was dried in vacuo at 100 °C for 12 h to obtain 25.64 g of 1,3-bis(4-aminophenoxy)benzene, with a molar yield of 96.59%, a purity of 99.97%, YI = 0.89, and the total metal ion content < 100 ppb.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing 1,3-bis(4-aminophenoxy)benzene, characterized in that: It includes the following steps: S1: Under the action of a protective gas, resorcinol, p-chloronitrobenzene, and a catalyst are added to a solvent for reaction; S2: After the reaction ends, the temperature is lowered, hydrogen is introduced for further reaction. After the reaction ends, post-treatment is carried out to obtain 1,3-bis(4-aminophenoxy)benzene; The preparation method of the catalyst includes the following steps: A1: Put the molecular sieve into an aqueous solution of palladium chloride, stir at room temperature to obtain a pretreated molecular sieve; A2: Dissolve imidazole in ethanol, add sodium hydroxide for reaction. After cooling to room temperature, add tetrabutylammonium bromide and continue to reflux. Filter the solid, add the pretreated molecular sieve into it, stir at room temperature, introduce hydrogen for further reaction, and evaporate ethanol at atmospheric pressure to obtain a white solid, which is the catalyst.

2. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: In step S1, the mass ratio of the catalyst to resorcinol is 0.1-0.4:

1.

3. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: In step S2, the post-treatment includes filtering to remove the catalyst, adding a poor solvent, lowering the temperature, precipitating a white solid, and drying the solid to obtain 1,3-bis(4-aminophenoxy)benzene.

4. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 3, characterized in that: The molar ratio of the solvent, poor solvent, p-chloronitrobenzene, and resorcinol is 50-80:40-60:2-2.2:

1.

5. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 4, characterized in that: The protective gas in step S1 is an inert gas, and the inert gas is nitrogen.

6. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 4, characterized in that: The solvent is a poor solvent.

7. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 4, characterized in that: The solvent includes one or more of methanol, ethanol, water, and acetonitrile.

8. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 4, characterized in that: The solvent is ethanol.

9. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The reaction temperature in step S1 is 60-90°C.

10. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 9, characterized in that: The temperature for cooling in step S2 is 50-80°C.

11. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The solvent in step S1 includes one or more of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

12. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The solvent is dimethylformamide.

13. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The molecular sieve in step A1 is one or more of SBA-15 molecular sieve, SBA-16, and MCM-41.

14. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The palladium chloride in step A1 is palladium dichloride.

15. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The concentration of the aqueous solution of palladium chloride is 0.5-1.2 g / L.

16. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The hydrogen pressure in step A2 is 0.1-0.3 MPa.

17. A method for preparing 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: In step A2, the molar ratio of ethanol, tetrabutylammonium bromide, sodium hydroxide, and imidazole is 60-90:1-1.2:1.1-1.3:

1.

18. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 1, characterized in that: The mass ratio of palladium chloride, imidazole, and the catalyst is 0.01-0.05:0.1-0.3:

1.

19. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 18, characterized in that: Add tetrabutylammonium bromide and continue to reflux for 6-10 h.

20. The preparation method of 1,3-bis(4-aminophenoxy)benzene according to claim 18, characterized in that: After adding the pretreated molecular sieve, slowly stir at room temperature for 4-9 h, introduce hydrogen for further reaction for 2-5 h, evaporate ethanol at atmospheric pressure to obtain a white solid, and vacuum dry the solid at 60-80°C for 10-15 h to obtain the catalyst.

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