Synthesis method of decabromodiphenylethane

Abstract

The invention provides a synthesis method of decabromodiphenylethane, and belongs to the technical field of brominated flame retardant synthesis. Benzene and 1, 2-dichloroethane are used as reaction raw materials, bromine chloride is used as a brominating agent, nitrobenzene is used as a solvent, and decabromodiphenylethane is synthesized through a one-pot two-step method. The diphenylethane produced in the first step does not need to be separated, and the catalyst in the first step can be directly used for bromination reaction, so that secondary addition of the catalyst is avoided. The method for synthesizing the decabromodiphenyl ethane has the advantages of simple and easily available raw materials, mild reaction conditions, low cost and high product yield.

Description

Technical Field

[0001] The invention belongs to the technical field of synthesis of brominated flame retardants, and particularly relates to a method for synthesizing decabromodiphenylethane. Background Art

[0002] Decabromodiphenylethane is a broad-spectrum additive flame retardant. It is a white powder with a theoretical bromine content of 82.3%. It has the advantages of good thermal stability, excellent fire resistance and UV resistance. There is no ether bond in its molecular structure. It will not produce carcinogenic substances such as PBDD and PBDF under high temperature conditions. It is particularly suitable for flame retardant production of high-end materials for computers, fax machines, telephones, copiers, home appliances, etc.

[0003] In the prior art, the preparation methods of decabromodiphenylethane all use 1,2-diphenylethane as raw material, and prepare decabromodiphenylethane by solvent method or excess bromine method. At present, the general industry mostly adopts the excess bromine method, heating 1,2-diphenylethane to a molten state, adding excess bromine to prepare the decabromodiphenylethane product, but this method also has pipeline blockage, and bromine, catalyst and target product are easily wrapped and agglomerated, resulting in yellow product color and high free bromine content. Regardless of the method, 1,2-diphenylethane is required as raw material, and the synthesis and separation and purification process of 1,2-diphenylethane is relatively complicated, resulting in a high production cost of decabromodiphenylethane using 1,2-diphenylethane as raw material.

[0004] The Chinese invention patent document with publication number CN114213210A discloses a method for preparing decabromodiphenylethane, which solves the technical problems of the prior art that the raw material 1,2-diphenylethane needs to be heated, the dropwise addition of molten 1,2-diphenylethane easily leads to the difficulty in completing the bromination reaction smoothly, and there is a risk of clogging the dropwise addition tube. However, the patent is complicated in operation and has high requirements for the raw material 1,2-diphenylethane, making it difficult to achieve large-scale industrial production.

[0005] The Chinese invention patent document with publication number 114213210 A discloses a method for preparing decabromodiphenylethane, which improves the whiteness and yield of decabromodiphenylethane by preparing a supported catalyst. However, the catalyst preparation in this patent is complicated, and the recycling of the catalyst is not reflected, resulting in high production costs of decabromodiphenylethane, which is not conducive to industrial production. Summary of the invention

[0006] The purpose of the present invention is to provide a method for synthesizing decabromodiphenylethane, wherein the method uses benzene and 1,2-dichloroethane as reaction raw materials, bromine chloride as a brominating agent, and nitrobenzene as a solvent to synthesize decabromodiphenylethane through a one-pot two-step method. The present invention has the advantages of simple and easy-to-obtain raw materials, mild reaction conditions, high product yield, low production cost, etc.

[0007] The technical solution of the present invention is: a method for synthesizing decabromodiphenylethane, the specific steps are as follows: (1) Mix the catalyst, benzene and nitrobenzene, raise the temperature to 40-70°C, add 1,2-dichloroethane dropwise for 1-3 hours, and keep the temperature for 4-7 hours after the addition is complete to obtain reaction material A; (2) subjecting the obtained reaction material A to vacuum distillation to remove excess benzene, then cooling the mixture to 0-10°C, adding bromine chloride dropwise for 1-2 hours, and heating the mixture to 20-40°C and keeping the temperature for 3-6 hours to obtain reaction material B; (3) The reaction material B prepared in step (2) is added with a sodium sulfite aqueous solution for neutralization until the color of the reaction solution changes from reddish brown to colorless, and then a sodium bicarbonate aqueous solution is added for neutralization until the pH value of the reaction solution is 7 to 8, and then the reaction solution is filtered, washed, and dried to obtain a finished decabromodiphenylethane.

[0008] The chemical reaction process of the above synthesis method is as follows:

[0009] Preferably, the catalyst described in step (1) is one of aluminum trichloride, ferric trichloride and antimony trichloride, and the molar ratio of the catalyst, benzene and 1,2-dichloroethane is 0.02-0.1:2-5:1; the molar ratio of nitrobenzene to 1,2-dichloroethane is 5-15:1.

[0010] Preferably, the molar ratio of bromine chloride to 1,2-dichloroethane in step (2) is 12 to 15:1.

[0011] Preferably, the molar ratio of bromine chloride to 1,2-dichloroethane in step (3) is 12 to 15:1.

[0012] The beneficial effects of the present invention are:

[0013] The technical solution provided by the present invention realizes the preparation of decabromodiphenylethane through a one-pot two-step method, avoids the separation and purification of the intermediate product 1,2-diphenylethane, simplifies the operation steps, avoids the material consumption and energy consumption of 1,2-diphenylethane separation, and simultaneously utilizes the catalyst of the first step to carry out the bromination reaction of the second step, thereby realizing the secondary utilization of the catalyst and reducing the amount of the catalyst.

[0014] The technical solution provided by the present invention uses benzene and 1,2-dichloroethane as reaction raw materials, bromine chloride as a brominating agent, and nitrobenzene as a solvent. The raw materials are simple and easy to obtain, and the reaction conditions are mild. The reaction temperature of the first step is 40-70°C, and the reaction temperature of the second step is 20-40°C. The catalyst and the solvent do not need to be separated and can be reused, thereby reducing the production cost. The product yield is high, and the yield is 86.4-90.5%, and it is easy to industrialize production. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention. Example 1

[0016] (1) Add 4 mmol aluminum chloride, 0.4 mol benzene and 1 mol nitrobenzene into a 1 L glass reactor, heat to 70 ° C, and then drop 0.2 mol 1,2-dichloroethane for 1 hour. After the dropwise addition is complete, keep the temperature for 4 hours to obtain reaction material A; (2) The obtained reaction material A was cooled to 30°C, and the excess benzene was removed by reduced pressure distillation at a vacuum degree of -0.08 to -0.09 MPa, and then cooled to 0°C, and 2.4 mol of bromine chloride was added dropwise for 2 hours. After the addition was completed, the temperature was raised to 20°C and kept warm for 6 hours to obtain reaction material B; (3) The reaction material B prepared in step (2) was neutralized by adding a 10% sodium sulfite aqueous solution until the color of the reaction solution changed from reddish brown to colorless, and then a 10% sodium bicarbonate aqueous solution was added to neutralize until the pH value of the reaction solution was 7-8, and then the reaction solution was filtered to obtain a crude decabromodiphenylethane product, which was washed with acetonitrile 3 times, and then washed with 80°C hot water 2 times, and dried in a vacuum drying oven at 150°C for 10 hours to obtain 167.8g of finished decabromodiphenylethane, with a yield of 86.4%. After testing, the whiteness of decabromodiphenylethane was 91.2°, the bromine content was 81.5%, the 1% TGA (thermogravimetric analysis) was 349.2°C, and the 5% TGA was 381.4°C. Example 2

[0017] (1) Add 0.02 mol of ferric chloride, 1 mol of benzene and 3 mol of nitrobenzene into a 1 L glass reactor, raise the temperature to 40°C, and then dropwise add 0.2 mol of 1,2-dichloroethane for 3 hours. After the dropwise addition is complete, keep the temperature for 7 hours to obtain reaction material A; (2) The obtained reaction material A was cooled to 30°C, and the excess benzene was removed by reduced pressure distillation at a vacuum degree of -0.08 to -0.09 MPa, and then cooled to 10°C, and 3 mol of bromine chloride was added dropwise for 1 hour. After the addition was completed, the temperature was raised to 40°C and kept warm for 3 hours to obtain reaction material B; (3) The reaction material B prepared in step (2) was neutralized by adding a 10% sodium sulfite aqueous solution until the color of the reaction solution changed from reddish brown to colorless, and then a 10% sodium bicarbonate aqueous solution was added to neutralize until the pH value of the reaction solution was 7-8, and then the reaction solution was filtered to obtain a crude decabromodiphenylethane product, which was washed with acetonitrile 3 times, and then washed with 80°C hot water 2 times, and dried in a vacuum drying oven at 150°C for 10 hours to obtain 175.8g of finished decabromodiphenylethane, with a yield of 90.5%. After testing, the whiteness of decabromodiphenylethane was 91.5°, the bromine content was 82.1%, the 1% TGA was 344.4°C, and the 5% TGA was 375.6°C. Example 3

[0018] (1) Add 0.01 mol of antimony trichloride, 0.6 mol of benzene and 1.6 mol of nitrobenzene into a 1 L glass reactor, raise the temperature to 60°C, and then dropwise add 0.2 mol of 1,2-dichloroethane for 2 hours. After the dropwise addition is complete, keep the temperature for 5 hours to obtain reaction material A; (2) The obtained reaction material A was cooled to 30°C, and the excess benzene was removed by reduced pressure distillation at a vacuum degree of -0.08 to -0.09 MPa, and then cooled to 5°C, and 2.6 mol of bromine chloride was added dropwise for 1.5 hours. After the addition was completed, the temperature was raised to 30°C and kept warm for 4 hours to obtain reaction material B; (3) The reaction material B prepared in step (2) was neutralized by adding a 10% sodium sulfite aqueous solution until the color of the reaction solution changed from reddish brown to colorless, and then a 10% sodium bicarbonate aqueous solution was added to neutralize until the pH value of the reaction solution was 7-8, and then the reaction solution was filtered to obtain a crude decabromodiphenylethane product, which was washed with acetonitrile 3 times, and then washed with 80°C hot water 2 times, and dried in a vacuum drying oven at 150°C for 10 hours to obtain 171.7g of decabromodiphenylethane finished product, with a yield of 88.4%. After testing, the whiteness of decabromodiphenylethane was 92.6°, the bromine content was 81.8%, the 1% TGA was 345.8°C, and the 5% TGA was 378.6°C. Example 4

[0019] (1) Add 0.012 mol aluminum chloride, 0.8 mol benzene and 2.4 mol nitrobenzene into a 1L glass reactor, raise the temperature to 50°C, and then dropwise add 0.2 mol 1,2-dichloroethane for 2 hours. After the dropwise addition is complete, keep the temperature for 6 hours to obtain reaction material A; (2) The obtained reaction material A was cooled to 30°C, and the excess benzene was removed by reduced pressure distillation at a vacuum degree of -0.08 to -0.09 MPa, and then cooled to 8°C, and 2.8 mol of bromine chloride was added dropwise for 2 hours. After the addition was completed, the temperature was raised to 30°C and kept warm for 5 hours to obtain reaction material B; (3) The reaction material B prepared in step (2) was neutralized by adding a 10% sodium sulfite aqueous solution until the color of the reaction solution changed from reddish brown to colorless, and then a 10% sodium bicarbonate aqueous solution was added to neutralize until the pH value of the reaction solution was 7-8, and then the reaction solution was filtered to obtain a crude decabromodiphenylethane product, which was washed with acetonitrile 3 times, and then washed with 80°C hot water 2 times, and dried in a vacuum drying oven at 150°C for 10 hours to obtain 173.3g of finished decabromodiphenylethane, with a yield of 89.2%. After testing, the whiteness of decabromodiphenylethane was 92.1°, the bromine content was 81.3%, the 1% TGA was 346.7°C, and the 5% TGA was 377.8°C. Example 5

[0020] (1) Add 8 mmol aluminum chloride, 0.6 mol benzene and 1.2 mol nitrobenzene into a 1 L glass reactor, raise the temperature to 50°C, and then dropwise add 0.2 mol 1,2-dichloroethane for 3 hours. After the dropwise addition is complete, keep the temperature for 5 hours to obtain a reaction mass; (2) The obtained reaction mass was cooled to 30°C, and the excess benzene was removed by reduced pressure distillation at a vacuum degree of -0.08 to -0.09 MPa, and then cooled to 3°C, and 2.6 mol of bromine chloride was added dropwise for 1 hour. After the addition was completed, the temperature was raised to 25°C and kept warm for 6 hours to obtain a reaction mass; (3) The reaction material B prepared in step (2) was neutralized by adding a 10% sodium sulfite aqueous solution until the color of the reaction solution changed from reddish brown to colorless, and then a 10% sodium bicarbonate aqueous solution was added to neutralize until the pH value of the reaction solution was 7-8, and then the reaction solution was filtered to obtain a crude decabromodiphenylethane product, which was washed with acetonitrile 3 times, and then washed with 80°C hot water 2 times, and dried in a vacuum drying oven at 150°C for 10 hours to obtain 172.3g of finished decabromodiphenylethane, with a yield of 88.7%. After testing, the whiteness of decabromodiphenylethane was 90.7°, the bromine content was 80.8%, the 1% TGA was 347.6°C, and the 5% TGA was 378.8°C. Example 6

[0021] (1) Add 0.016 mol of antimony trichloride, 0.8 mol of benzene and 2 mol of nitrobenzene into a 1 L glass reactor, raise the temperature to 60°C, and then dropwise add 0.2 mol of 1,2-dichloroethane for 1 hour. After the dropwise addition is complete, keep the temperature for 6 hours to obtain a reaction mass; (2) The obtained reaction mass was cooled to 30°C, and the excess benzene was removed by reduced pressure distillation at a vacuum degree of -0.08 to -0.09 MPa, and then cooled to 6°C, and 2.4 mol of bromine chloride was added dropwise for 1.5 hours. After the addition was completed, the temperature was raised to 35°C and kept warm for 5 hours to obtain a reaction mass; (3) The reaction material B prepared in step (2) was neutralized by adding a 10% sodium sulfite aqueous solution until the color of the reaction solution changed from reddish brown to colorless, and then a 10% sodium bicarbonate aqueous solution was added to neutralize until the pH value of the reaction solution was 7-8, and then the reaction solution was filtered to obtain a crude decabromodiphenylethane product, which was washed with acetonitrile 3 times, and then washed with 80°C hot water 2 times, and dried in a vacuum drying oven at 150°C for 10 hours to obtain 171.1g of finished decabromodiphenylethane, with a yield of 88.1%. After testing, the whiteness of decabromodiphenylethane was 90.4°, the bromine content was 81.1%, the 1% TGA was 346.2°C, and the 5% TGA was 378.8°C. Comparative Example 1

[0022] The difference from Example 1 is that the reaction temperature in step (1) is changed from 70°C to 80°C, and the other conditions are the same. After drying, the product is 160.2g of decabromodiphenylethane finished product, with a yield of 82.5%. After testing, the whiteness of decabromodiphenylethane is 87.8°, the bromine content is 81.4%, the 1% TGA (thermogravimetric analysis) is 344.2°C, and the 5% TGA is 374.6°C. Comparative Example 2

[0023] The difference from Example 1 is that the reaction temperature in step (1) is changed from 70°C to 30°C, and the other conditions are the same. After drying, the product is 154.6g of decabromodiphenylethane finished product, with a yield of 79.6%. After testing, the whiteness of decabromodiphenylethane is 87.5°, the bromine content is 81.2%, the 1% TGA (thermogravimetric analysis) is 343.2°C, and the 5% TGA is 373.5°C.

[0024]

[0025] It can be seen from Table 1 that the technical solution provided by the present application can obtain a decabromodiphenylethane yield of 86.4-90.5%, while the comparative example and the embodiment only differ in reaction temperature, and the decabromodiphenylethane yield will be reduced, indicating that the reaction temperature effect of the present invention is better.

[0026] In addition to the above embodiments, the present invention also includes other implementation modes. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A method for synthesizing decabromodiphenylethane, characterized in that: The following steps are involved: (1) Mix the catalyst, benzene and nitrobenzene, raise the temperature to 40-70°C, add 1,2-dichloroethane dropwise for 1-3 hours, and keep the temperature for 4-7 hours after the addition is complete to obtain reaction material A; (2) subjecting the obtained reaction material A to vacuum distillation to remove excess benzene, then cooling the mixture to 0-10°C, adding bromine chloride dropwise for 1-2 hours, and heating the mixture to 20-40°C and keeping the temperature for 3-6 hours to obtain reaction material B; (3) The reaction material B prepared in step (2) is added with a sodium sulfite aqueous solution for neutralization until the color of the reaction solution changes from reddish brown to colorless, and then a sodium bicarbonate aqueous solution is added for neutralization until the pH value of the reaction solution is 7 to 8, and then the reaction solution is filtered, washed, and dried to obtain a finished decabromodiphenylethane.

2. The method for synthesizing decabromodiphenylethane according to claim 1, characterized in that: The catalyst described in step (1) is one of aluminum trichloride, ferric trichloride and antimony trichloride, and the molar ratio of the catalyst, benzene and 1,2-dichloroethane is 0.02-0.1:2-5:

1.

3. The method for synthesizing decabromodiphenylethane according to claim 1, characterized in that: The molar ratio of nitrobenzene to 1,2-dichloroethane in step (1) is 5 to 15:

1.

4. The method for synthesizing decabromodiphenylethane according to claim 1, characterized in that: The molar ratio of bromine chloride to 1,2-dichloroethane in step (2) is 12 to 15:1.

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