The invention relates to 3, 3apos; 4, 4 apos, 4, 4 apos; refining method of biphenyltetracarboxylic acid
Crystallization is carried out by using a mixture of acetic acid, ketone solvent and water and 3,3',4,4'-biphenyltetrachloric acid seed crystals in 3,3',4,4'-biphenyltetrachloric acid crude product Methods solve the problems of the use of toxic reagents, low whiteness, low purity and complex process in the existing purification methods, and achieve the purification effect of high purity, high whiteness and simple process.
Patent Information
- Application Number
- CN202411309166.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2025-02-07
AI Technical Summary
The existing purification methods of 3,3',4,4'-biphenyltetrachloric acid have problems such as the use of toxic reagents, low product whiteness, low product purity, and complex purification process.
Acetic acid, ketone solvent and water were mixed at 90-100°C, and 3,3',4,4'-biphenyltetracarboxylic acid seeds were added to cool down and crystallize, and 3,3',4,4'-biphenyl tetracarboxylic acid was prepared. Berthalic acid fine.
The total metal ions of the product are low, high purity, increased whiteness to more than 98%, and simple process. The purification of high yield and high purity is achieved by only one solid-liquid separation.
Smart Images
Figure CN119390562A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chemical purification, and in particular to a method for refining 3,3',4,4'-biphenyltetracarboxylic acid. Background Art
[0002] 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride is one of the important monomers of polyimide, and 3,3′,4,4′-biphenyltetracarboxylic acid is the main raw material for preparing 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride. The polyimide synthesized with 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride as raw material is the super heat-resistant resin with the highest heat resistance temperature at present, and its mechanical properties, hydrolysis resistance and flexibility are superior to the traditional polyimide materials synthesized from pyromellitic acid dianhydride monomer, and it is widely used in the electronics industry. At present, with the continuous improvement of the performance requirements of polyimide materials, in the synthesis process, the whiteness of the dianhydride monomer is required to be >90% and the metal ion is <0.5ppm, which leads to higher requirements for the purification effect of 3,3′,4,4′-biphenyltetracarboxylic acid.
[0003] The current purification method of 3,3′,4,4′-biphenyltetracarboxylic acid has the problems of using toxic reagents, low product whiteness, low product purity, and complex purification process. For example, patent CN114507130A discloses a purification method of 3,3′,4,4′-biphenyltetracarboxylic acid, which uses a mixed solution of amides and water as a solvent, dissolves 3,3′,4,4′-biphenyltetracarboxylic acid by heating, and precipitates it into crystals by cooling. However, when amide solvents are heated with water, they are easily hydrolyzed to produce dimethylamine, which is easy to react with biphenyltetracarboxylic acid to reduce the purity of the product. In addition, amide solvents are easily oxidized and yellowed, which can easily cause the color of the refined product to be yellowish. N,N-dimethylformamide is also highly toxic and harmful to the human body. Therefore, it is necessary to develop a new purification method for 3,3′,4,4′-biphenyltetracarboxylic acid. Summary of the invention
[0004] In order to overcome the problems existing in the prior art, the object of the present invention is to provide a method for refining 3,3',4,4'-biphenyltetracarboxylic acid.
[0005] In order to achieve the above object, the technical solution adopted by the present invention is:
[0006] The present invention provides a method for refining 3,3',4,4'-biphenyltetracarboxylic acid, comprising the following steps:
[0007] S1, mixing crude 3,3′,4,4′-biphenyltetracarboxylic acid, acetic acid, a ketone solvent and water at 90-100° C. to obtain a crude biphenyltetracarboxylic acid solution;
[0008] S2. Mix the crude biphenyltetracarboxylic acid solution and 3,3′,4,4′-biphenyltetracarboxylic acid seed crystals at 80-90° C. to obtain a mixed solution, and cool and crystallize the solution to obtain fine 3,3′,4,4′-biphenyltetracarboxylic acid.
[0009] Preferably, in step S1, the mass ratio of the crude 3,3′,4,4′-biphenyltetracarboxylic acid to acetic acid is 100:(2-8).
[0010] More preferably, in step S1, the mass ratio of the crude 3,3′,4,4′-biphenyltetracarboxylic acid to acetic acid is 100:(3-6).
[0011] Preferably, in step S1, the mass ratio of the crude 3,3′,4,4′-biphenyltetracarboxylic acid to the ketone solvent is 1:(1-3).
[0012] More preferably, in step S1, the mass ratio of the crude 3,3′,4,4′-biphenyltetracarboxylic acid to the ketone solvent is 1:(2-3).
[0013] Preferably, the mass ratio of the crude 3,3′,4,4′-biphenyltetracarboxylic acid to water is 1:(6-10).
[0014] More preferably, the mass ratio of the crude 3,3′,4,4′-biphenyltetracarboxylic acid to water is 1:(7-9).
[0015] Preferably, in step S1, the ketone solvent is selected from at least one of 1-methyl-2-pyrrolidone, 2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-methyl-3-pyrrolidone, 1-hydroxyethyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone.
[0016] More preferably, in step S1, the ketone solvent is selected from 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, and 1-methyl-3-pyrrolidone.
[0017] The ketone solvents selected in the present invention are all low-toxic reagents and have little harm to the human body.
[0018] Preferably, in step S1, the mixing is performed at 95-100°C.
[0019] Preferably, in step S1, the specific step of mixing is: stirring until the mixed system is completely dissolved.
[0020] Preferably, step S1 specifically comprises the following steps: firstly, adding acetic acid to the ketone solvent and water, and then slowly adding the crude 3,3′,4,4′-biphenyltetracarboxylic acid under stirring conditions, mixing, and obtaining a crude biphenyltetracarboxylic acid solution.
[0021] Preferably, in step S2, the mass ratio of crude 3,3′,4,4′-biphenyltetracarboxylic acid to 3,3′,4,4′-biphenyltetracarboxylic acid seed crystals in the crude biphenyltetracarboxylic acid solution is 1:(0.002-0.006).
[0022] More preferably, in step S2, the mass ratio of crude 3,3′,4,4′-biphenyltetracarboxylic acid to 3,3′,4,4′-biphenyltetracarboxylic acid seed crystals in the crude biphenyltetracarboxylic acid solution is 1:(0.002-0.004).
[0023] Preferably, in step S2, the purity of the 3,3′,4,4′-biphenyltetracarboxylic acid seed crystals is greater than 99.95%, and the bulk density is 0.7 to 0.8 g / cm 3 .
[0024] More preferably, in step S2, the purity of the 3,3′,4,4′-biphenyltetracarboxylic acid seed crystals is 99.95-99.98%, and the bulk density is 0.75-0.78 g / cm 3 .
[0025] Preferably, in step S2, the mixing is performed at 85-90°C.
[0026] Preferably, in step S2, the crystallization temperature of the temperature drop crystallization is 5 to 10°C, and the crystallization time is 3 to 6 hours.
[0027] Preferably, in step S2, the cooling procedure of the cooling crystallization is: firstly cooling from 80-90°C to 60°C at a cooling rate of 0.5-1°C / min, and then cooling to 5-10°C at a cooling rate of 1-2°C / min.
[0028] Preferably, step S2 further comprises the following steps: after cooling and crystallizing, solid-liquid separation, washing and drying are sequentially performed to obtain 3,3′,4,4′-biphenyltetracarboxylic acid fine product; the drying temperature is 100-120°C.
[0029] More preferably, the solid-liquid separation is carried out by filtration or centrifugation.
[0030] More preferably, the washing specifically comprises: washing the solid product with water.
[0031] More preferably, the drying temperature is 110-120° C. and the drying time is 5-8 hours.
[0032] The beneficial effects of the present invention are:
[0033] The invention provides a method for refining 3,3′,4,4′-biphenyltetracarboxylic acid, which has the following advantages: (i) the total metal ion content of the product is low and the purity is high. In the refining method of the invention, acetic acid is used as an ion exchanger. When the crude 3,3′,4,4′-biphenyltetracarboxylic acid product is recrystallized and dissolved, the metal ions in the solution are adsorbed and acidic conditions are provided, so that the product molecules can form a tetracarboxylic acid structure, thereby improving the metal ion removal effect and the product purity, and the total metal ions can be reduced to below 0.2 ppm; (ii) the product yield is high. In the refining method of the invention, adding seed crystals is beneficial to controlling the crystallization process, improving the crystallization rate, and ensuring the product quality. Using acetic acid and seed crystals in the crystallization process can synergistically improve the product yield; (iii) the refining method provided by the invention can effectively improve the whiteness of the product, and the whiteness can be improved to more than 98%; (iv) the refining method provided by the invention is simple in process, and a high-yield and high-purity purification process can be completed by only performing solid-liquid separation once. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is the liquid phase spectrum of the fine product of 3,3′,4,4′-biphenyltetracarboxylic acid obtained in Example 1. DETAILED DESCRIPTION
[0035] The present invention is further described in detail below through specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial sources or prepared and separated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.
[0036] The crude 3,3′,4,4′-biphenyltetracarboxylic acid used in the examples and comparative examples has a purity of 89.58%; the total amount of metal ions is 22.808 ppm, of which Na is 16.1 ppm, Mg is 0.14 ppm, K is 2.78 ppm, Ca is 3.16 ppm, and Fe is 0.628 ppm.
[0037] Example 1
[0038] This embodiment provides a method for refining 3,3',4,4'-biphenyltetracarboxylic acid, and the specific steps are as follows:
[0039] S1. Add 220 g of 1-methyl-2-pyrrolidone, 780 g of deionized water and 4 g of glacial acetic acid to a clean 2000 mL three-necked flask, slowly add 100 g of crude 3,3′,4,4′-biphenyltetracarboxylic acid while stirring, and raise the temperature to 100° C. until the system is dissolved;
[0040] S2, cool down to 85-90℃ at a rate of 0.5-1℃ / min, add 0.3g of 99.96% pure and 0.7g / cm 3The 3,3′,4,4′-biphenyltetracarboxylic acid seed crystals were further cooled to 60°C at a rate of 0.5-1°C / min, and then cooled to 8°C at a rate of 1-2°C / min. The mixture was kept warm for 4 hours and filtered. The filter cake was washed with water and finally placed in a forced air drying oven and kept warm at 120°C for 8 hours to obtain 95.4 g of 3,3′,4,4′-biphenyltetracarboxylic acid fine product.
[0041] Material characterization of the obtained product:
[0042] 1. The whiteness of the obtained product was tested, and the test result showed that the whiteness was 98%;
[0043] 2. Use liquid chromatography to detect the purity of the product. Figure 1 This is the liquid phase spectrum of the fine product of 3,3′,4,4′-biphenyltetracarboxylic acid obtained in Example 1. Table 1 is the peak data of the liquid phase spectrum:
[0044] Table 1
[0045]
[0046]
[0047] The area % of the target peak 3-5 is 99.811%, so the purity of the product is 99.811%;
[0048] 3. The metal ion content of the obtained product was tested, and the results are shown in Table 2:
[0049] Table 2
[0050]
[0051] The metal ion content of the obtained product was 0.176 ppm.
[0052] Example 2
[0053] This embodiment provides a method for refining 3,3',4,4'-biphenyltetracarboxylic acid, and the specific steps are as follows:
[0054] S1. Add 200g of 1-methyl-2-pyrrolidone, 600g of deionized water and 8g of glacial acetic acid to a clean 2000mL three-necked flask, slowly add 100g of crude 3,3′,4,4′-biphenyltetracarboxylic acid while stirring, and raise the temperature to 100°C until the system is dissolved;
[0055] S2, cool down to 85-90℃ at a rate of 0.5-1℃ / min, add 0.3g of 99.96% pure and 0.7g / cm 3The mixture was cooled to 60°C at a rate of 0.5-1°C / min, and then cooled to 10°C at a rate of 1-2°C / min. The mixture was filtered after keeping the temperature for 5 hours. The filter cake was washed with water and finally kept at 120°C in a forced air drying oven for 8 hours to obtain 94.4g of 3,3′,4,4′-biphenyltetracarboxylic acid fine product (the indicators were tested by the method of Example 1, the same below: whiteness 98%, purity 99.80%, and metal ion content 0.181ppm).
[0056] Example 3
[0057] This embodiment provides a method for refining 3,3',4,4'-biphenyltetracarboxylic acid, and the specific steps are as follows:
[0058] S1. Add 200g 1-methyl-3-pyrrolidone, 630g deionized water and 4g glacial acetic acid to a clean 2000mL three-necked flask, slowly add 100g crude 3,3′,4,4′-biphenyltetracarboxylic acid while stirring, and raise the temperature to 100°C until the system is dissolved;
[0059] S2, cool down to 85-90℃ at a rate of 0.5-1℃ / min, add 0.3g of 99.96% pure and 0.7g / cm 3 The mixture was cooled to 60°C at a rate of 0.5-1°C / min, and then to 8°C at a rate of 1-2°C / min. The mixture was filtered after keeping the temperature for 4 hours, and the filter cake was washed with water. Finally, the mixture was placed in a forced air drying oven and kept at 120°C for 8 hours to obtain 94.0 g of 3,3′,4,4′-biphenyltetracarboxylic acid product (whiteness 98%, purity 99.77%, and metal ion content 0.189 ppm).
[0060] Comparative Example 1
[0061] This comparative example provides a method for refining 3,3′,4,4′-biphenyltetracarboxylic acid, and the specific steps are as follows:
[0062] Add 220g 1-methyl-2-pyrrolidone and 780g deionized water to a clean 2000mL three-necked flask, slowly add 100g crude 3,3′,4,4′-biphenyltetracarboxylic acid, heat to 100°C until the system is dissolved, cool to 85-90°C at a rate of 0.5-1°C / min, add 0.3g of 99.96% pure and 0.7g / cm 3The mixture was cooled to 60°C at a rate of 0.5-1°C / min, and then to 8°C at a rate of 1-2°C / min. The mixture was filtered after keeping the temperature for 4 hours, and the filter cake was washed with water. Finally, the filter cake was placed in a forced air drying oven and kept at 120°C for 8 hours to obtain 84.6 g of 3,3′,4,4′-biphenyltetracarboxylic acid fine product (whiteness 95%, purity 99.74%, metal ion content 0.378 ppm).
[0063] Comparative Example 2
[0064] This comparative example provides a method for refining 3,3′,4,4′-biphenyltetracarboxylic acid, and the specific steps are as follows:
[0065] Add 220g 1-methyl-2-pyrrolidone, 780g deionized water and 2g glacial acetic acid to a clean 2000mL three-necked flask, slowly add 100g crude 3,3′,4,4′-biphenyltetracarboxylic acid while stirring, raise the temperature to 100°C until the system is dissolved, cool to 85-90°C at a rate of 0.5-1°C / min, add 0.3g of 99.96% pure and 0.7g / cm 3 The mixture was cooled to 60°C at a rate of 0.5-1°C / min, and then to 8°C at a rate of 1-2°C / min. The mixture was filtered after keeping the temperature for 4 hours, and the filter cake was washed with water. Finally, the filter cake was placed in a forced air drying oven and kept at 120°C for 8 hours to obtain 89.1 g of 3,3′,4,4′-biphenyltetracarboxylic acid fine product (whiteness 94%, purity 99.65%, metal ion content 0.307 ppm).
[0066] Comparative Example 3
[0067] This comparative example provides a method for refining 3,3′,4,4′-biphenyltetracarboxylic acid, and the specific steps are as follows:
[0068] Add 200g of 1-methyl-2-pyrrolidone and 400g of deionized water to a clean 2000mL three-necked flask, slowly add 100g of crude 3,3′,4,4′-biphenyltetracarboxylic acid while stirring, raise the temperature to 80°C until the system is dissolved, add 0.45g of 99.96% pure and 0.75g / cm 3 The 3,3′,4,4′-biphenyltetracarboxylic acid seed crystals were cooled to 60°C at a rate of 0.5-1°C / min, then cooled to 5°C at a rate of 1-2°C / min, kept warm for 4 hours, filtered, and the filter cake was washed with water. Finally, the filter cake was placed in a forced air drying oven and kept warm at 110°C for 7 hours to obtain 85.2 g of 3,3′,4,4′-biphenyltetracarboxylic acid fine product (whiteness 85%, purity 99.58%, metal ion content 0.487 ppm).
[0069] Comparative Example 4
[0070] This comparative example provides a method for refining 3,3′,4,4′-biphenyltetracarboxylic acid, and the specific steps are as follows:
[0071] 100g of crude 3,3′,4,4′-biphenyltetracarboxylic acid with a purity of 97.8% was placed in 1000g of methanol water (20%) solution, heated to 75°C and refluxed for 2h, cooled to 30°C, filtered, washed with 300mL of pure water, and dried. 82.1g of refined 3,3′,4,4′-biphenyltetracarboxylic acid (whiteness 83%, purity 99.68%, metal ion content 14.358ppm) was obtained.
[0072] Material Characterization Analysis
[0073] Table 3 is a comparison of the indicators of 3,3′,4,4′-biphenyltetracarboxylic acid prepared in Examples 1 to 3 and Comparative Examples 1 to 4:
[0074] Table 3
[0075]
[0076] As can be seen from Table 1, in terms of product yield, the product yields of 3,3′,4,4′-biphenyltetracarboxylic acid treated in Examples 1 to 3 of the present invention are 95.4%, 94.4% and 94%, respectively, and the product yields of 3,3′,4,4′-biphenyltetracarboxylic acid treated in Comparative Examples 1 to 4 are 84.6%, 89.6%, 85.2% and 82.1%, respectively. The difference between Comparative Example 1 and Example 1 is that acetic acid is not added, and the difference between Comparative Example 2 and Example 1 is that a small amount of acetic acid is added. The product yields of Comparative Example 1 and Comparative Example 2 are both inferior to those of Example 1, indicating that the refining method provided by the present invention can significantly improve the product yield and reduce the loss.
[0077] In terms of whiteness, compared with comparative examples 3 to 4, the whiteness of the products of Examples 1 to 3 is significantly improved, indicating that the refining method provided by the present invention can effectively improve the whiteness of the product.
[0078] In terms of metal ion content, compared with comparative examples 1 to 4, the metal ion content in the products of Examples 1 to 3 is more significantly reduced, indicating that the refining method provided by the present invention is more effective in removing metal ions in the crude 3,3′,4,4′-biphenyltetracarboxylic acid, and the total metal ions can be reduced to below 0.2 ppm.
[0079] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.
Claims
1. A method for refining 3,3',4,4'-biphenyltetracarboxylic acid, characterized in that: The steps include: S1, mixing crude 3,3',4,4'-biphenyltetracarboxylic acid, acetic acid, a ketone solvent and water at 90-100° C. to obtain a crude biphenyltetracarboxylic acid solution; S2. Mix the crude biphenyltetracarboxylic acid solution and 3,3',4,4'-biphenyltetracarboxylic acid seed crystals at 80-90° C. to obtain a mixed solution, and cool and crystallize the solution to obtain fine 3,3',4,4'-biphenyltetracarboxylic acid.
2. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: In step S1, the mass ratio of the crude 3,3',4,4'-biphenyltetracarboxylic acid to acetic acid is 100:(2-8).
3. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: In step S1, the mass ratio of the crude 3,3',4,4'-biphenyltetracarboxylic acid to the ketone solvent is 1:(1-3); And / or, the mass ratio of the crude 3,3',4,4'-biphenyltetracarboxylic acid to water is 1:(6-10).
4. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: In step S1, the ketone solvent is selected from at least one of 1-methyl-2-pyrrolidone, 2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-methyl-3-pyrrolidone, 1-hydroxyethyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.
5. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: Step S1 specifically includes the following steps: firstly, acetic acid is added to a ketone solvent and water, and then, crude 3,3',4,4'-biphenyltetracarboxylic acid is slowly added under stirring conditions, and the mixture is mixed to obtain a crude biphenyltetracarboxylic acid solution.
6. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: In step S2, the mass ratio of the crude 3,3',4,4'-biphenyltetracarboxylic acid to the 3,3',4,4'-biphenyltetracarboxylic acid seed crystals in the crude biphenyltetracarboxylic acid solution is 1:(0.002-0.006).
7. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: In step S2, the purity of the 3,3',4,4'-biphenyltetracarboxylic acid seed crystals is >99.95%, and the bulk density is 0.7-0.8 g / cm 3 .
8. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: In step S2, the crystallization temperature of the cooling crystallization is 5 to 10°C, and the crystallization time is 3 to 6 hours.
9. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 8, characterized in that: In step S2, the cooling procedure of the cooling crystallization is: firstly cooling from 80-90°C to 60°C at a cooling rate of 0.5-1°C / min, and then cooling to 5-10°C at a cooling rate of 1-2°C / min.
10. The method for refining 3,3',4,4'-biphenyltetracarboxylic acid according to claim 1, characterized in that: Step S2 also includes the following steps: after cooling and crystallization, solid-liquid separation, washing and drying are performed in sequence to obtain 3,3',4,4'-biphenyltetracarboxylic acid fine product; the drying temperature is 100-120°C.