Preparation method of aromatic diether dicarboxylic acid

Abstract

The invention belongs to the field of chemical synthesis, and particularly relates to a preparation method of aromatic diether dicarboxylic acid, which comprises the following steps: (1) under the protection of inert gas, adding aromatic diphenol, p-fluorobenzonitrile, basic carbonate and a solvent 1 into a reactor, and reacting at 120-150 DEG C for 10-20 hours to obtain aromatic diether dinitrile; and (2) adding aromatic diether dinitrile, alkali metal hydroxide and a solvent 2 into the reactor, reacting at 100-150 DEG C for 10-20 hours, neutralizing with inorganic acid until the pH value is 1-2, filtering, washing with water until the pH value is neutral, and drying to obtain the product. By selecting specific reaction raw materials and process conditions, higher yield is successfully realized at lower temperature, and the method is very suitable for industrial production of aromatic diether dicarboxylic acid.

Description

Technical Field

[0001] The invention belongs to the field of chemical synthesis, and particularly relates to a method for preparing aromatic diether diformic acid. Background Art

[0002] Aromatic dicarboxylic acid is a major organic synthesis intermediate that can undergo reactions such as salt formation, dehydration, hydrogenation, halogenation, and acylation. It has a wide range of uses in coatings, polyester resins, unsaturated polyester resins, specialty fibers, thermal adhesives, printing inks, coordination polymer supramolecular materials, synthesis of liquid crystal products, polyester fiber dyeing and modification, and resin plasticization.

[0003] Compared with common aromatic dicarboxylic acid monomers, aromatic diether dicarboxylic acid, due to the introduction of bifunctional groups in the monomer, can improve the effective collision probability of reactive groups in the polymerization reaction, increase the monomer utilization rate, improve the yield of polymers, and alleviate the problem of tight supply of dicarboxylic acid monomers. At the same time, the introduction of more benzene rings can effectively improve the melting point of the prepared polymer, increase its flexibility, and broaden the application field of polymer materials.

[0004] Patent CN110204459A discloses a method for preparing an aromatic diether dicarboxylic acid, which uses aromatic diphenol and p-chlorobenzonitrile to react to finally obtain an aromatic diether dicarboxylic acid. However, the preparation process needs to be carried out at a relatively high temperature, has high requirements on the heat resistance of the equipment, and has a low production yield.

[0005] Therefore, there is still a need in the art for improved methods of preparing aromatic diether diformic acids. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a method for preparing an aromatic diether diformic acid as shown in formula (I) or (II), which comprises the following steps:

[0007] (1) under the protection of inert gas, adding aromatic diphenol, p-fluorobenzonitrile, basic carbonate and solvent 1 into a reactor, reacting at 120-150° C. for 10-20 hours to obtain aromatic diether dicarbonitrile;

[0008] (2) adding an aromatic diether dicarbonitrile, an alkali metal hydroxide and a solvent 2 into a reactor, reacting at 100-150° C. for 10-20 hours, then neutralizing with an inorganic acid to a pH of 1-2, filtering, washing with water until neutral, and drying to obtain a product, i.e., an aromatic diether dicarboxylic acid as shown in formula (I) or (II)

[0009]

[0010] Wherein, taking the synthesis of bisphenol A acid as an example, the reaction formula of the synthesis reaction of step (1) is:

[0011]

[0012] The reaction formula of the synthesis reaction of step (2) is:

[0013]

[0014] Furthermore, the molar ratio of the aromatic diphenol to p-fluorobenzonitrile is 1:2-3, and the molar ratio of p-fluorobenzonitrile to basic carbonate is 1:1.1-1.5.

[0015] Furthermore, the molar ratio of the aromatic diether dicarbonitrile to the alkali metal hydroxide is 1:4-10.

[0016] Furthermore, the aromatic diphenol is bisphenol A or bisphenol fluorene.

[0017] Furthermore, the basic carbonate is at least one of potassium carbonate or sodium carbonate.

[0018] Furthermore, the solvent 1 is at least one of N,N-dimethylformamide, N-methylpyrrolidone, sulfolane or dimethyl sulfoxide.

[0019] Furthermore, the alkali metal hydroxide is at least one of potassium hydroxide or sodium hydroxide.

[0020] Furthermore, the solvent 2 is selected from at least one of ethanol, methanol, water, ethylene glycol, and dimethyl sulfoxide.

[0021] Furthermore, the inorganic acid is selected from at least one of hydrochloric acid, dilute sulfuric acid, dilute nitric acid and phosphoric acid.

[0022] Furthermore, step (1) includes cooling the reaction system to 50-80° C. after the reaction is completed, then adding water until no precipitation is generated, and collecting and washing the precipitate, namely the aromatic diether dicarbonitrile.

[0023] Furthermore, step (2) includes cooling the reaction system to 50-80°C after the reaction is completed, neutralizing it with an inorganic acid, and after neutralizing it to pH = 1-2, keeping it at 70-80°C for 2 hours.

[0024] Furthermore, step (2) further comprises washing the wet product with water to a neutral state and further purifying the wet product, which comprises, for example, recrystallizing the product with an alcohol solvent.

[0025] The present invention also provides an aromatic diether dicarboxylic acid as shown in formula (I) or (II), which is prepared by the method described above.

[0026] Beneficial Effects of the Invention

[0027] The present invention uses p-fluorobenzonitrile to replace p-chlorobenzonitrile used in patent CN110204459A to synthesize bisphenol A acid and bisphenol fluorene acid, and successfully achieves a higher yield at a lower temperature. In addition, the present invention also improves the synthesis process, thereby further improving the yield. DETAILED DESCRIPTION

[0028] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0029] Example 1

[0030] A method for preparing bisphenol A acid comprises the following steps:

[0031] (1) Synthesis of Bisphenol A Nitrile

[0032] 1. Add 33 kg of DMF, 8.1 kg of bisphenol A, 8.8 kg of p-fluorobenzonitrile and 10.4 kg of potassium carbonate into a 100 L kettle.

[0033] 2. After adding, stir and heat up.

[0034] 3. Keep the temperature at 120 degrees for 18 hours until the raw material content is less than 0.5%.

[0035] 4. After the reaction is qualified, cool to 60 degrees, add 47KG of water and stir for half an hour. A large amount of solids will appear. Continue to put the filtered filtrate into the kettle. After most of the solids are filtered out, continue to add 20KG of water, continue to filter, put the filtrate into a barrel, continue to filter the solids, and add water to about four times the amount of DMF. Add 147KG of water in total until no solids come out of the filtrate when water is added. The filtrate can be discarded.

[0036] 5. Filter to obtain 21 kg of wet material, add 42 kg of water at a ratio of 1:2 and wash with water, heat to 80-90 degrees, wash with water and filter to obtain 19.5 kg of bisphenol A nitrile wet product with a solid content of 76%. The filtered water is used for wastewater treatment.

[0037] (2) Synthesis of Bisphenol A Acid

[0038] 1. Add 19.5 kg of bisphenol A nitrile, 50 kg of ethylene glycol, and 26 kg of 50% potassium hydroxide aqueous solution.

[0039] 2. After adding, stir and heat up. When the temperature reaches 100 degrees, it needs to be slowly raised to 120 degrees. If the temperature rises too quickly at this time, there will be a phenomenon of material rushing.

[0040] 3. After 120 degrees, react for 12 hours. After the central control confirms the end, start to cool down to 60 degrees, add 36 kg of hydrochloric acid, and control the dripping time to be completed within 2 hours. The temperature will rise during the dripping, so don't drip too fast. After dripping, stir for 1 hour and measure the pH. Strong acidity 1-2 is required. Stir for two hours and re-measure the pH. Strong acidity. Keep warm at 70-80 degrees for two hours.

[0041] 4. Cool down to 30-40 degrees and filter to obtain 39.5 kg of wet product. Wash the wet product with 60 kg of water, stir for 2 hours and filter to obtain 38 kg of wet product washed to neutrality.

[0042] 5. Add 54 kg of DMF to 38 kg of wet product, heat to 120 degrees to dissolve completely, reflux and dehydrate. Then cool to about 100 degrees and filter hot (the kettle must be full of liquid). Pour the filtered DMF liquid into another kettle with 50 kg of methanol added in advance. A large amount of solid precipitates, heat to 60 degrees and stir for 2 hours, then cool to 0-5 degrees and stir for two hours.

[0043] 6. Filter to obtain 29 kg of refined bisphenol A acid wet product. After drying, 15.5 kg of bisphenol A acid finished product is obtained with a yield of 93%.

[0044] Example 2

[0045] A method for preparing bisphenol fluorene acid comprises the following steps:

[0046] (1) Synthesis of bisphenol fluorene nitrile

[0047] 1. Add 40 kg of DMF, 10 kg of bisphenol fluorene, 7.0 kg of p-fluorobenzonitrile and 9.0 kg of potassium carbonate into a 100 L kettle.

[0048] 2. After adding, stir and heat up.

[0049] 3. Keep the temperature at 120 degrees for 12 hours until the raw material content is less than 0.5%.

[0050] 4. After the reaction is qualified, cool to 60 degrees, add 20KG of water and stir for half an hour. A large amount of solids will appear. Continue to put the filtered filtrate into the kettle. After most of the solids are filtered out, continue to add 20KG of water, continue to filter, put the filtrate into a barrel, continue to filter the solids, and add water to about four times the amount of DMF. Add 160KG of water in total until no solids come out of the filtrate when water is added. The filtrate can be discarded.

[0051] 5. Filter to obtain 30 kg of wet material, add water at a ratio of 1:2 and wash with water, heat to 80-90 degrees, wash with water and filter to obtain 21.4 kg of bisphenol fluorene nitrile wet product. The filtered water is used for wastewater treatment.

[0052] (2) Synthesis of bisphenol fluorene acid

[0053] 1. Add 10.8 kg of bisphenol fluorene nitrile, 40 kg of ethylene glycol, and 13 kg of 50% potassium hydroxide aqueous solution.

[0054] 2. After adding, stir and heat up. When the temperature reaches 100 degrees, it needs to be heated up slowly. If the temperature is raised too quickly at this time, there will be a phenomenon of material rushing.

[0055] 3. After 140 degrees, react for 12 hours. After the central control confirms the end, start to cool down to 60 degrees, add 16.8 kg of hydrochloric acid, and control the dripping time to be completed within 2 hours. The temperature will rise during the dripping, so don't drip too fast. After dripping, stir for 1 hour and measure the pH. Strong acidity 1-2 is required. Stir for two hours and re-measure the pH. Strong acidity. Keep warm at 70-80 degrees for two hours.

[0056] 4. Cool down to 30-40 degrees and filter to obtain 26 kg of wet product. Wash the wet product with 60 kg of water, stir for 2 hours and filter to obtain 30 kg of wet product washed to neutrality.

[0057] 5. Add 50 kg of DMF to 30 kg of wet product, heat to 120 degrees to dissolve completely, reflux and dehydrate. Then cool to about 100 degrees and filter hot (the kettle must be full of liquid). Pour the filtered DMF liquid into another kettle with 50 kg of methanol added in advance. A large amount of solid precipitates, heat to 60 degrees and stir for 2 hours, then cool to 0-5 degrees and stir for two hours.

[0058] 6. Filter to obtain 32 kg of refined bisphenol fluorene acid wet product. After drying, 17.6 kg of bisphenol fluorene acid finished product is obtained with a yield of 93.6%.

[0059] Comparative Example 1

[0060] A method for preparing bisphenol A acid, which differs from Example 1 in that in step (1), 10.8 kg of p-chlorobenzonitrile is used instead of p-fluorobenzonitrile. Finally, 11.6 kg of bisphenol A acid product is obtained with a yield of 69.9%. This indicates that when p-fluorobenzonitrile monomer is used, a higher yield cannot be achieved under the process conditions of the present invention.

[0061] Comparative Example 2

[0062] A method for preparing bisphenol A acid, which differs from Example 1 in that in step 4 of step (1), the temperature of the reaction system is cooled to room temperature before adding water for precipitation, instead of 60 degrees in Example 1. Finally, 12.4 kg of bisphenol A acid product is obtained with a yield of 74.7%, indicating that the temperature of this step is crucial to achieving a higher yield.

[0063] Comparative Example 3

[0064] A method for preparing bisphenol A acid, which differs from Example 1 in that in step 3 of step (2), the temperature of the reaction system is cooled to room temperature before adding hydrochloric acid, instead of 60 degrees in Example 1. Finally, 12.8 kg of bisphenol A acid product is obtained with a yield of 77.2%, indicating that the temperature of this step is crucial to achieving a higher yield.

[0065] It should be noted that the preferred embodiments of the present invention are given in the specification of the present invention, but the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the present invention specification; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the protection scope of the claims attached to the present invention.

Claims

1. A method for preparing an aromatic diether dicarboxylic acid as shown in formula (I) or (II), characterized in that: The following steps are involved: (1) under the protection of inert gas, adding aromatic diphenol, p-fluorobenzonitrile, basic carbonate and solvent 1 into a reactor, reacting at 120-150° C. for 10-20 hours to obtain aromatic diether dicarbonitrile; (2) adding an aromatic diether dicarbonitrile, an alkali metal hydroxide and a solvent 2 into a reactor, reacting at 100-150° C. for 10-20 hours, then neutralizing with an inorganic acid to a pH of 1-2, filtering, washing with water until neutral, and drying to obtain a product, i.e., an aromatic diether dicarboxylic acid as shown in formula (I) or (II) 2. The preparation method according to claim 1, characterized in that: The molar ratio of aromatic diphenol to p-fluorobenzonitrile is 1:2-3, and the molar ratio of p-fluorobenzonitrile to basic carbonate is 1:1.1-1.5; Further, the molar ratio of the aromatic diether dicarbonitrile to the alkali metal hydroxide is 1:4-10; Furthermore, the aromatic diphenol is bisphenol A or bisphenol fluorene.

3. The preparation method according to claim 1, characterized in that: The basic carbonate is at least one of potassium carbonate or sodium carbonate.

4. The preparation method according to claim 1, characterized in that: The solvent 1 is at least one of N,N-dimethylformamide, N-methylpyrrolidone, sulfolane or dimethyl sulfoxide.

5. The preparation method according to claim 1, characterized in that: The alkali metal hydroxide is at least one of potassium hydroxide or sodium hydroxide.

6. The preparation method according to claim 1, characterized in that: The solvent 2 is selected from at least one of ethanol, methanol, water, ethylene glycol and dimethyl sulfoxide.

7. The preparation method according to claim 1, characterized in that: The inorganic acid is selected from at least one of hydrochloric acid, dilute sulfuric acid, dilute nitric acid and phosphoric acid.

8. The preparation method according to claim 1, characterized in that: Step (1) comprises cooling the reaction system to 50-80° C. after the reaction is completed, then adding water until no precipitation is generated, and collecting and washing the precipitate, namely the aromatic diether dicarbonitrile.

9. The preparation method according to claim 1, characterized in that: Step (2) comprises cooling the reaction system to 50-80°C after the reaction is completed, neutralizing it with an inorganic acid, and after neutralizing it to pH = 1-2, keeping it at 70-80°C for 2 hours.

10. An aromatic diether dicarboxylic acid as represented by formula (I) or (II), which is prepared by the method according to any one of claims 1 to 9.

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