The invention discloses a method for preparing N, Napos through a micro-channel reaction. Process for the preparation of-(carbonyl bis (4, 1-phenylene)) bis (3-nitrobenzamide)

Abstract

The invention relates to a method for preparing N, N '-(carbonyl bis (4, 1-phenylene)) bis (3-nitrobenzamide) through a microchannel reaction, the N, N'-(carbonyl bis (4, 1-phenylene)) bis (3-nitrobenzamide) is prepared by using a continuous flow microchannel reactor and ethylene glycol butyl ether as a solvent, the reaction is more uniform, few by-products are produced, the yield is high, continuous reaction can be realized, and the method is suitable for industrial production. Meanwhile, a solvent adopted in the reaction can be recycled after reduced pressure distillation, and the solvent is marked as an environment-friendly solvent and has relatively good safety; the preparation method has the advantages of mild preparation conditions, low production cost, easiness in batch and large-scale production, strong universality, good industrial production basis and wide application prospect.

Description

Technical Field

[0001] The invention relates to a method for preparing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) by microchannel reaction, belonging to the technical field of organic synthesis. Background Art

[0002] Polyimide (PI) is an aromatic heterocyclic polymer compound with imide chain segments in its molecular structure. It is one of the most heat-resistant types of engineering plastics and is widely used in aviation, aerospace, microelectronics, nanotechnology, liquid crystal, laser and other fields. Polyimide is known as the top material of the polymer material pyramid and is also called "the problem solver". Some industry insiders even believe that "without polyimide, there would be no microelectronics technology today." In recent years, countries have listed the research, development and utilization of PI as one of the development priorities of new chemical materials in the 21st century. Polyimide, due to its outstanding characteristics in performance and synthesis, has great application prospects whether as a structural material or as a functional material.

[0003] N, N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) is one of the important raw materials for preparing photosensitive polyimide resins. Its synthesis route refers to patent document CN102549497.A. The existing method for synthesizing 2,2-bis[(3-aminobenzamide)-4-hydroxyphenyl]hexafluoropropane is to obtain the product by amidation of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and m-nitrobenzoyl chloride. The amount of m-nitrobenzoyl chloride is large and it is highly corrosive, which can easily lead to rust of production equipment and cause serious safety hazards. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for preparing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) by microchannel reaction in order to overcome the problems of many by-products, imprecise temperature control, imprecise droplet speed, and difficult treatment of three wastes in the traditional process.

[0005] The invention utilizes a continuous flow microchannel reactor and uses ethylene glycol butyl ether as a solvent to prepare N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide), and the reaction is more uniform, less by-products, high yield, and continuous reaction. Meanwhile, the solvent used in the reaction can be recycled after reduced pressure distillation, and the solvent is marked as an environmentally friendly solvent and has good safety. The invention has mild preparation conditions, low production cost, easy batch and large-scale production, strong universality, and a good industrial production foundation and broad application prospects.

[0006] The specific technical solutions of the present invention are as follows:

[0007] A method for preparing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) by microchannel reaction comprises the following steps:

[0008] (1) fully mixing 4,4'-diaminobenzophenone and ethylene glycol butyl ether and preheating them to obtain a mixed solution;

[0009] (2) mixing ethylene glycol butyl ether and m-nitrobenzoyl chloride uniformly to obtain an acylating agent solution;

[0010] (3) pumping the mixed solution into microchannel 1 of the microchannel reactor, and the acylating agent solution into microchannel 2 of the microchannel reactor, and controlling the flow rate of the materials by a metering pump, so that the mixed solution in microchannel 1 is dripped into the acylating agent solution in microchannel 2 at a certain flow rate for mixing reaction, and the product flows out from the outlet of the reactor;

[0011] (4) The material obtained at the outlet of the microchannel reactor is post-treated to obtain pure N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide).

[0012] Preferably, according to the present invention, in step (1), the mass of ethylene glycol butyl ether is 2 to 8 times the mass of 4,4'-diaminobenzophenone, and preferably, the mass of ethylene glycol butyl ether is 2 to 6 times the mass of 4,4'-diaminobenzophenone.

[0013] Preferably according to the present invention, in step (1), the preheating temperature is 0 to 60°C, preferably the preheating temperature is 0 to 30°C.

[0014] Preferably according to the present invention, in step (2), the mass ratio of m-nitrobenzoyl chloride to ethylene glycol butyl ether is 1:2.2.

[0015] Preferably according to the present invention, in step (2), the molar ratio of 4,4'-diaminobenzophenone to m-nitrobenzoyl chloride is 1:3.5-4.5.

[0016] Preferably, according to the present invention, in step (3), the reaction temperature of the microchannel reactor is controlled by an external heat exchanger, the heat exchange medium is heat transfer oil, the reaction temperature is 10 to 70° C., and the reaction residence time is 5 to 180 s.

[0017] More preferably, the reaction temperature is 15-45° C., and the reaction residence time is 30-90 s.

[0018] Preferably according to the present invention, the microchannel reactor module is a direct-flow microchannel reactor or an enhanced mixing type continuous flow microchannel reactor, the cross-sectional shape of the direct-flow microchannel reactor is a circular ring, and the enhanced mixing type continuous flow microchannel reactor series module is composed of 5 Corning high-throughput microchannel reactors with heart-shaped channels connected in series.

[0019] Preferably according to the present invention, the direct-flow microchannel reactor and the enhanced mixing continuous flow microchannel reactor are made of any one of glass, metal element, alloy, ceramic, single crystal silicon, and fluorine-containing resin, and the hydraulic diameter of the channel is 0.5-5mm.

[0020] Preferably, according to the present invention, in step (3), the flow rate at which the mixed solution in microchannel 1 is dripped into microchannel 2 is 4-10 g / min.

[0021] Preferably, in step (4), the post-treatment is sequentially precipitation filtration, metal ion removal, pure water purification, and drying, and the precipitation filtration is adding an alcohol solvent for precipitation and then filtering, and the mass of the alcohol solvent is 2 to 5 times the mass of 4,4'-diaminobenzophenone.

[0022] Preferably, according to the present invention, in step (4), the alcohol solvent is a methanol aqueous solution, the precipitation temperature is 10-25° C., and the mass ratio of methanol to water in the methanol aqueous solution is 1:1-3.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention adopts a microchannel reactor to react and prepare N, N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide). The microchannel reactor can quickly dissipate heat, the reaction is more uniform, the by-products are less, the yield is high, and the reaction can be continuous, which is suitable for industrial production;

[0025] 2. The present invention adopts a microchannel reactor for reaction, which has rapid reaction and greatly shortens the reaction time; in addition, the heat transfer performance is excellent, temperature runaway is avoided, and the mass transfer and heat transfer efficiency of the reaction can be significantly improved;

[0026] 3. The present invention adopts a microchannel reactor to react and prepare N, N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide), the reaction container is small in size and highly safe, and the potential safety hazards are greatly reduced in actual production;

[0027] 4. The present invention adopts a microchannel reactor to carry out the reaction, which avoids the intermediate separation step in the reaction process, simplifies the operation, shortens the reaction time, and improves the production efficiency;

[0028] 5. Since the microchannel reactor equipment occupies a small area, is easy to operate, has stable product quality, and has a high degree of process matching, the synthesis route process of the present invention is simpler and easier to operate. Compared with the existing synthesis route, it has higher safety, less three wastes, is more environmentally friendly, has lower production costs, and can ensure a higher yield, so it is more suitable for large-scale industrial production.

[0029] 6. The solvent is marked as an environmentally friendly solvent and has good safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The process flow chart of the method for preparing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) by microchannel reaction. DETAILED DESCRIPTION

[0031] Unless otherwise specified, all raw materials used in the following examples are commercially available products.

[0032] Example 1

[0033] (1)Reference Figure 1 The connection mode is determined, and the heat exchange medium of the heat exchanger is thermal oil. The diameter of the microchannel reactor is 0.5 mm.

[0034] (2) 100 g of 4,4'-diaminobenzophenone (0.47 mol) and 200 g of DEF were mixed and stirred to form a 6FAP solution; m-nitrobenzoyl chloride was melted in hot water in advance, and 306.17 g (1.65 mol) of m-nitrobenzoyl chloride was weighed after it was completely melted, and 673.57 g of DEF was added to dissolve the m-nitrobenzoyl chloride. The flow rate of the material was controlled by a metering pump, so that the mixed solution in microchannel 1 (after preheating at 25°C) was added dropwise to the acylating agent in microchannel 2 at a flow rate of 8.6 g / min for mixing reaction; at this time, the molar ratio of 4,4'-diaminobenzophenone to m-nitrobenzoyl chloride was 1:3.5, the reaction temperature was controlled to 45°C, the residence time was 60 s, and the reaction product was cooled by a cooling coil to obtain a discharge liquid containing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide).

[0035] (3) The discharge liquid was slowly poured into 400 g of ethanol aqueous solution (ethanol 200 g + pure water 200 g), and the mixture was filtered and separated using a Buchner funnel. Finally, the crude product was washed with pure water in small amounts and multiple times. After being dried at 80°C, the refined N, N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) was obtained. The mother liquor was decompressed to recover methanol and then recycled through a microchannel reactor. The reaction yield was 97.3% and the purity was 98.7%.

[0036] Example 2

[0037] (1)Reference Figure 1 The connection mode is determined, and the heat exchange medium of the heat exchanger is thermal oil. The diameter of the microchannel reactor is 3 mm.

[0038] (2) 100 g of 4,4'-diaminobenzophenone (0.47 mol) and 400 g of DEF were mixed and stirred to form a 6FAP solution; m-nitrobenzoyl chloride was melted in hot water in advance, and 322.87 (1.74 mol) of m-nitrobenzoyl chloride was weighed after it was completely melted, and 710.31 g of DEF was added to dissolve the m-nitrobenzoyl chloride. The flow rate of the material was controlled by a metering pump, so that the mixed solution in microchannel 1 (after preheating at 25°C) was added dropwise to the acylating agent in microchannel 2 at a flow rate of 8.6 g / min for mixing reaction; at this time, the molar ratio of 4,4'-diaminobenzophenone to m-nitrobenzoyl chloride was 1:3.7, the reaction temperature was controlled to 45°C, the residence time was 60 s, and the reaction product was cooled by a cooling coil to obtain a discharge liquid containing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide).

[0039] (3) The discharge liquid was slowly poured into 400 g of ethanol aqueous solution (ethanol 200 g + pure water 200 g), and the mixture was filtered and separated using a Buchner funnel. Finally, the crude product was washed with pure water in small amounts and multiple times. After being dried at 80°C, the refined N, N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) was obtained. The mother liquor was decompressed to recover methanol and then recycled through a microchannel reactor. The reaction yield was 97.8% and the purity was 98.4%.

[0040] Example 3

[0041] (1)Reference Figure 1 The connection mode is determined, and the heat exchange medium of the heat exchanger is thermal oil. The diameter of the microchannel reactor is 5 mm.

[0042] (2) 100 g of 4,4'-diaminobenzophenone (0.47 mol) and 300 g of DEF were mixed and stirred to form a 6FAP solution; m-nitrobenzoyl chloride was melted in hot water in advance, and 348.85 g (1.88 mol) of m-nitrobenzoyl chloride was weighed after it was completely melted, and 767.47 g of DEF was added to dissolve the m-nitrobenzoyl chloride. The flow rate of the material was controlled by a metering pump, so that the mixed solution in microchannel 1 (after preheating at 25°C) was added dropwise to the acylating agent in microchannel 2 at a flow rate of 8.6 g / min for mixing reaction; at this time, the molar ratio of 4,4'-diaminobenzophenone to m-nitrobenzoyl chloride was 1:4, the reaction temperature was controlled to be 45°C, the residence time was 60 s, and the reaction product was cooled by a cooling coil to obtain a discharge liquid containing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide).

[0043] (3) The discharge liquid was slowly poured into 400 g of ethanol aqueous solution (ethanol 200 g + pure water 200 g), and the mixture was filtered and separated using a Buchner funnel. Finally, the crude product was washed with pure water in small amounts and multiple times. After being dried at 80°C, the refined N, N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) was obtained. The mother liquor was decompressed to recover methanol and then recycled through a microchannel reactor. The reaction yield was 96.5% and the purity was 98.8%.

[0044] Example 4

[0045] (1)Reference Figure 1 The connection mode is determined, and the heat exchange medium of the heat exchanger is thermal oil. The diameter of the microchannel reactor is 3 mm.

[0046] (2) 100 g of 4,4'-diaminobenzophenone (0.47 mol) and 500 g of DEF were mixed and stirred to form a 6FAP solution; m-nitrobenzoyl chloride was melted in hot water in advance, and 374.83 g (2.02 mol) of m-nitrobenzoyl chloride was weighed after it was completely melted, and 824.63 g of DEF was added to dissolve the m-nitrobenzoyl chloride. The flow rate of the material was controlled by a metering pump, so that the mixed solution in microchannel 1 (after preheating at 25°C) was added dropwise to the acylating agent in microchannel 2 at a flow rate of 8.6 g / min for mixing reaction; at this time, the molar ratio of 4,4'-diaminobenzophenone to m-nitrobenzoyl chloride was 1:4.3, the reaction temperature was controlled to 45°C, the residence time was 50 s, and the reaction product was cooled by a cooling coil to obtain a discharge liquid containing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide).

[0047] (3) The discharge liquid was slowly poured into 400 g of ethanol aqueous solution (ethanol 200 g + pure water 200 g), and the mixture was filtered and separated using a Buchner funnel. Finally, the crude product was washed with pure water in small amounts and multiple times. After being dried at 80°C, the refined N, N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) was obtained. The mother liquor was decompressed to recover methanol and then recycled through a microchannel reactor. The reaction yield was 97.2% and the purity was 98.5%.

[0048] Experimental example

[0049] 1. The amount of ethylene glycol butyl ether in Example 1 was changed to 50g, 61g, 92g, 300g, and 360g respectively. The rest was carried out according to Example 1. After the reaction was completed, the reaction yield and purity were compared. The results are shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] It can be seen from the data in Table 1 that when the dosage of ethylene glycol butyl ether is too small, the yield is low. As the dosage of ethylene glycol butyl ether increases, the yield gradually increases. However, when the dosage of ethylene glycol butyl ether is too large, the yield begins to show a downward trend. The excessive dosage of ethylene glycol butyl ether affects the product yield and produces side reactions that affect the product purity.

[0054] 2. The reaction time in Example 1 was changed to 5 h, 4 h, 3.5 h, 2 h, 1 h, and 0.5 h, respectively; the rest was carried out as in Example 1. After the reaction was completed, the reaction yield and purity were compared. The results are shown in Table 2.

[0055] Table 2

[0056] Reaction time Yield % purity% 5h 96.2 98.8 4h 96.4 98.9 3.5h 96.3 98.8 2h 96.3 99.92 1h 95.8 98.5 0.5h 93.0 95

[0057] It can be seen from the data in Table 2 that if the reaction time is too short, the reaction is not complete, resulting in residual raw materials, resulting in relatively low yield and purity. If the reaction time is extended, the yield will increase. However, if the reaction time is too long, the reaction yield will decrease to a certain extent. This is because if the reaction time is too long, side reactions may occur, and the purity will also decrease.

Claims

1. A method for preparing N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide) by microchannel reaction, comprising the following steps: (1) 4,4'-diaminobenzophenone and ethylene glycol butyl ether are fully mixed and preheated to obtain a mixed solution; (2) mixing ethylene glycol butyl ether and m-nitrobenzoyl chloride uniformly to obtain an acylating agent solution; (3) pumping the mixed solution into microchannel 1 of the microchannel reactor, and the acylating agent solution into microchannel 2 of the microchannel reactor, and controlling the flow rate of the materials by a metering pump, so that the mixed solution in microchannel 1 is dripped into the acylating agent solution in microchannel 2 at a certain flow rate for mixing reaction, and the product flows out from the outlet of the reactor; (4) The material obtained at the outlet of the microchannel reactor is post-treated to obtain pure N,N'-(carbonylbis(4,1-phenylene))bis(3-nitrobenzamide).

2. The method according to claim 1, characterized in that In step (1), the mass of ethylene glycol butyl ether is 2 to 8 times the mass of 4,4'-diaminobenzophenone. Preferably, the mass of ethylene glycol butyl ether is 4 to 7 times the mass of 4,4'-diaminobenzophenone.

3. The method according to claim 1, characterized in that: In step (1), the preheating temperature is 0 to 60°C, preferably 0 to 30°C.

4. The method according to claim 1, characterized in that In step (2), the mass ratio of m-nitrobenzoyl chloride to ethylene glycol butyl ether is 1:2.

2.

5. The method according to claim 1, characterized in that In step (2), the molar ratio of 4,4'-diaminobenzophenone to m-nitrobenzoyl chloride is 1:3.5-4.

5.

6. The method according to claim 1, characterized in that In step (3), the reaction temperature of the microchannel reactor is controlled by an external heat exchanger, the heat exchange medium is heat transfer oil, the reaction temperature is 10 to 70° C., and the reaction residence time is 5 to 180 s.

7. The method according to claim 1, characterized in that The reaction temperature is 15-45°C, and the reaction residence time is 30-90s.

8. The method according to claim 1, characterized in that In step (3), the mixed solution in microchannel 1 is dripped into microchannel 2 at a flow rate of 4-10 g / min.

9. The method according to claim 1, characterized in that: In step (4), the post-treatment is sequentially carried out through precipitation filtration, The metal ions are removed, purified with pure water, and dried. The precipitation and filtration are performed by adding an alcohol solvent for precipitation and then filtering. The mass of the alcohol solvent is 2 to 5 times the mass of 4,4'-diaminobenzophenone.

10. The method according to claim 1, characterized in that In step (4), the alcohol solvent is a methanol aqueous solution, the precipitation temperature is 10-25° C., and the mass ratio of methanol to water in the methanol aqueous solution is 1:1-3.

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