Green and environment-friendly method for preparing 2, 2-bis (3-m-nitrobenzamide-4-hydroxyphenyl) hexafluoropropane

Abstract

The invention relates to a green and environment-friendly method for preparing 2, 2-bis (3-m-nitrobenzamide-4-hydroxyphenyl) hexafluoropropane, ethylene glycol butyl ether is used as a solvent to prepare the 2, 2-bis (3-m-nitrobenzamide-4-hydroxyphenyl) hexafluoropropane, the use of the ethylene glycol butyl ether promotes the reaction of 6FAP and an acylating agent, the reaction efficiency is improved, and the yield of the 2, 2-bis (3-m-nitrobenzamide-4-hydroxyphenyl) hexafluoropropane is increased. The preparation method has the advantages of simple operation, high yield, and overcoming of the problems of difficult recovery, high cost and incapability of industrial production caused by trifluoroacetic acid, acetic acid or nitric acid as a solvent, and the preparation method has the advantages of mild preparation conditions, low production cost, easy batch and large-scale production, strong universality, good industrial production basis and wide application prospects.

Description

Technical Field

[0001] The invention relates to a green and environmentally friendly method for preparing 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane, belonging to the technical field of organic synthesis. Background Art

[0002] Polyimide (PI) is an aromatic heterocyclic polymer compound with an imide chain link 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 "a 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] 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane is one of the important raw materials for preparing photosensitive polyimide resins, and its synthesis route refers to patent document CN102549497A. The existing synthesis method of 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane is to obtain the product by amidation of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and m-nitrobenzoyl chloride. In the actual production process using m-nitrobenzoyl chloride, a large amount of waste water will be generated, which does not conform to the green and environmentally friendly production concept. At the same time, most of the existing technologies use trifluoroacetic acid and acetic acid as solvents. Trifluoroacetic acid is expensive and corrosive and is not suitable for industrial production, while acetic acid is not easy to recover and has high cost. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a green and environmentally friendly method for preparing 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane.

[0005] The invention adopts ethylene glycol butyl ether as a solvent to prepare 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane. The use of ethylene glycol butyl ether promotes the reaction of 6FAP and an acylating agent, improves the reaction efficiency, greatly improves the yield, and overcomes the problems of being difficult to recover, high cost, and unable to be industrialized due to trifluoroacetic acid, acetic acid or nitric acid as a solvent. The invention has mild preparation conditions, low production cost, easy batch and large-scale production, strong universality, and a good industrialized production foundation and broad application prospects.

[0006] Terminology

[0007] 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is abbreviated as 6FAP.

[0008] The specific technical solutions of the present invention are as follows:

[0009] A green and environmentally friendly method for preparing 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane comprises the following steps:

[0010] 6FAP and ethylene glycol butyl ether are mixed into a homogeneous solution, and then m-nitrobenzoyl chloride dissolved in ethylene glycol butyl ether is added dropwise at 0-25° C., and the mixture is kept warm at 15-45° C. for 1-2 hours. After the reaction, the product 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane is obtained by post-treatment.

[0011] According to the present invention, preferably, the mass of ethylene glycol butyl ether is 4 to 10 times the mass of 6FAP, and further preferably, the mass of ethylene glycol butyl ether is 4 to 7 times the mass of 6FAP.

[0012] Preferably according to the present invention, the molar ratio of 6FAP to m-nitrobenzoyl chloride is 1:1-6.

[0013] Preferably, according to the present invention, the post-treatment is sequentially precipitation filtration, removal of metal ions, pure water purification, and drying, the precipitation filtration is adding an alcohol solvent for precipitation and then filtering, the alcohol solvent is a methanol aqueous solution, the mass of the alcohol solvent is 3 to 6 times the mass of 6FAP, the precipitation temperature is 10 to 25°C, and the mass ratio of ethanol to water in the methanol aqueous solution is 1:1 to 3.

[0014] Further preferably, the metal ions are removed by adding a deionizing agent to the product obtained after filtration to remove the metal ions, and the deionizing agent is deionized formamide, and the mass of the deionized formamide is 5 to 10 times the mass of 6FAP.

[0015] More preferably, the product after pure water purification to remove metal ions is added with pure water for stirring, the mass of the pure water is 1 to 4 times the mass of 6FAP, and the number of times of pure water purification is 3 to 5 times.

[0016] More preferably, the drying is forced air drying at 70-90°C.

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

[0018] The invention adopts ethylene glycol butyl ether as a solvent to prepare 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane. The use of ethylene glycol butyl ether promotes the reaction of 6FAP and an acylating agent, improves the reaction efficiency, greatly improves the yield, and overcomes the problems of being difficult to recover, high cost, and unable to be industrialized due to trifluoroacetic acid, acetic acid or nitric acid as a solvent. The invention has mild preparation conditions, low production cost, easy batch and large-scale production, strong universality, and a good industrialized production foundation and broad application prospects. DETAILED DESCRIPTION

[0019] Unless otherwise specified, all raw materials used in the following examples are commercially available products.

[0020] 6FAP 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is a commercially available product.

[0021] Example 1

[0022] A green and environmentally friendly method for preparing 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane, the steps are as follows:

[0023] 1) Add 183.15 g (0.987 mol) of m-nitrobenzoyl chloride into a beaker containing 183.15 g of ethylene glycol butyl ether and stir evenly to obtain a m-nitrobenzoyl chloride solution;

[0024] 2) Add 150 g 6FAP (0.41 mol) into a three-necked flask containing 600 g ethylene glycol butyl ether, stir until completely dissolved, and cool to 20° C. after complete dissolution to obtain a mixed solution;

[0025] 3) The m-nitrobenzoyl chloride solution is added dropwise to the three-necked flask in step 2) through a latex tube using a peristaltic pump. The addition time is 0.5h. The temperature during the reaction is less than 30°C. After the addition is completed, the temperature is adjusted to 25°C. The reaction is continued for 2h. After the reaction is completed, 900g of methanol aqueous solution (450g of methanol and 450g of pure water) is slowly poured into the reaction solution. The mixture is filtered and separated using a Buchner funnel. Deionized formamide is added to the product obtained after filtration to remove metal ions. The mass of deionized formamide is 5 times the mass of 6FAP. Finally, the crude product is washed with pure water in small amounts and multiple times. After being dried at 80°C, refined 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane is obtained. The mother liquor is decompressed to recover methanol and then recycled through a microchannel reactor. The reaction yield is 96.2% and the purity is 98.7%.

[0026] Example 2

[0027] A green and environmentally friendly method for preparing 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane, the steps are as follows:

[0028] 1) Add 183.15 g (0.987 mol) of m-nitrobenzoyl chloride into a beaker containing 183.15 g of ethylene glycol butyl ether and stir evenly to obtain a m-nitrobenzoyl chloride solution;

[0029] 2) Add 150 g 6FAP (0.41 mol) into a three-necked flask containing 750 g ethylene glycol butyl ether, stir until completely dissolved, and cool to 20° C. after complete dissolution to obtain a mixed solution;

[0030] 3) The m-nitrobenzoyl chloride solution is added dropwise to the three-necked flask in step 2) through a latex tube using a peristaltic pump. The addition time is 0.5h. The temperature during the reaction is less than 30°C. After the addition is completed, the temperature is adjusted to 25°C. The reaction is continued for 2h. After the reaction is completed, 900g of methanol aqueous solution (450g of methanol and 450g of pure water) is slowly poured into the reaction solution. The mixture is filtered and separated using a Buchner funnel. Deionized formamide is added to the product obtained after filtration to remove metal ions. The mass of deionized formamide is 5 times the mass of 6FAP. Finally, the crude product is washed with pure water in small amounts and multiple times. After being dried at 80°C, refined 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane is obtained. The mother liquor is decompressed to recover methanol and then recycled through a microchannel reactor. The reaction yield is 95.8% and the purity is 98.3%.

[0031] Comparative Example 1

[0032] The method described in Example 1 is different in that:

[0033] In step (1), N-methylpyrrolidone was used instead of ethylene glycol butyl ether. The other steps were carried out as in Example 1. The reaction yield of the product was 70.8% and the purity was 80.6%.

[0034] Comparative Example 2

[0035] The method described in Example 1 is different in that:

[0036] In step (1), acetone was used instead of ethylene glycol butyl ether, and the rest was carried out as in Example 1. The reaction yield of the product was 72.8% and the purity was 79.3%.

[0037] Comparative Example 3

[0038] The method described in Example 1 is different in that:

[0039] In step (1), methanol was used instead of ethylene glycol butyl ether, and the rest was carried out as in Example 1. The reaction yield of the product was 75.8% and the purity was 79.9%.

[0040] In summary, it can be seen from Comparative Examples 1-4 that the reaction yield is significantly reduced when the microchannel reactor is not used, and the yield of the product is also reduced when N-methylpyrrolidone, acetone, methanol, and ethanol are used instead of ethylene glycol butyl ether.

[0041] Experimental example

[0042] 1. The amount of ethylene glycol butyl ether in Example 1 was changed to 50g, 100g, 150g, 1800g, and 2000g 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.

[0043] Table 1

[0044] Dosage of Ethylene Glycol Butyl Ether Yield % purity% 50g 68.4 72.5 100g 73.5 72.8 150g 78.4 80.4 600g 95.3 98.5 750g 96.8 98.4 900g 96.4 98.1 1800g 94.7 97.6 2000g 94.2 97.2

[0045] It can be seen from the data in Table 1 that the amount of ethylene glycol butyl ether is too small and the yield is low. With the increase of the amount of ethylene glycol butyl ether, the yield gradually increases. However, when the amount of ethylene glycol butyl ether exceeds 750g, the yield begins to show a downward trend. The amount of ethylene glycol butyl ether is too large, which affects the product yield and produces side reactions that affect the product purity.

[0046] 2. The mass ratio of methanol to pure water in Example 1 was changed to 8:2, 7:3, 6:4, 1:1, 4:6, and 3:7, 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.

[0047] Table 2

[0048] The ratio of methanol to pure water Yield % purity% 8:2 94.0 95.45 7:3 94.7 96.2 6:4 94.8 96 1:1 95.3 98.5 4:6 94.9 96.3 3:7 94.6 97

[0049] It can be seen from the data in Table 3 that when the mass ratio of methanol to pure water is 1:1, the yield and purity are the highest.

Claims

1. A green and environmentally friendly method for preparing 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane, comprising the following steps: 6FAP and ethylene glycol butyl ether are mixed into a homogeneous solution, and then m-nitrobenzoyl chloride dissolved in ethylene glycol butyl ether is added dropwise at 0-25° C., and the mixture is kept warm at 15-45° C. for 1-2 hours. After the reaction, the product 2,2-bis(3-m-nitrobenzamide-4-hydroxyphenyl)hexafluoropropane is obtained by post-treatment.

2. The method according to claim 1, characterized in that The mass of ethylene glycol butyl ether is 4 to 10 times that of 6FAP.

3. The method according to claim 1, characterized in that The mass of ethylene glycol butyl ether is 4 to 7 times that of 6FAP.

4. The method according to claim 1, characterized in that: The molar ratio of 6FAP to m-nitrobenzoyl chloride is 1:1-6.

5. The method according to claim 1, characterized in that The post-treatment is sequentially precipitation filtration, removal of metal ions, pure water purification, and drying. The precipitation filtration is to add an alcohol solvent for precipitation and then filter. The alcohol solvent is a methanol aqueous solution. The mass of the alcohol solvent is 3 to 6 times the mass of 6FAP. The precipitation temperature is 10 to 25° C., and the mass ratio of ethanol to water in the methanol aqueous solution is 1:1 to 3.

6. The method according to claim 5, characterized in that The metal ions are removed by adding a deionizing agent to the product obtained after filtration to remove the metal ions. The deionizing agent is deionized formamide, and the mass of the deionized formamide is 5 to 10 times the mass of 6FAP.

7. The method according to claim 5, characterized in that The product after the metal ions are purified by pure water is added into pure water for stirring. The mass of the pure water is 1 to 4 times the mass of 6FAP, and the number of times of the pure water purification is 3 to 5 times.

8. The method according to claim 5, characterized in that Drying is carried out at 70-90°C with forced air.