Synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene

Abstract

The present invention belongs to the technical field of organic synthesis, and specifically relates to a synthesis process of high-yield 1,4-bis(4-phenoxybenzoyl)benzene. The process is mainly prepared by using excess diphenyl ether and terephthaloyl chloride as reaction raw materials, using o-dichlorobenzene as reaction solvent, and under the catalytic action of aluminum chloride. The synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene provided by the present invention successfully overcomes many challenges existing in traditional synthesis methods, such as many side reactions, low yield, and purification difficulties, by optimizing key parameters such as reaction conditions, solvent selection, catalyst dosage, and sample addition order. It is not only easy to operate, but also significantly improves the yield of the target compound, and also ensures the high purity and low impurity content of the product.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a synthesis process of high-yield 1,4-bis(4-phenoxybenzoyl)benzene. Background Art

[0002] 1,4-bis(4-phenoxybenzoyl)benzene is a starting material for preparing polyetherketoneketone polymers. As described in Chinese patents CN110621647B, CN110650939B, and CN110637004B, it is prepared by Friedel-Crafts acylation of terephthaloyl chloride and diphenyl ether under the catalysis of Lewis acid using o-dichlorobenzene as solvent. The reaction formula is as follows: Figure 1 shown.

[0003] However, during the preparation process, since the ortho position of diphenyl ether is also active, once the ortho position of diphenyl ether participates in the reaction, it will produce Figure 2 The product (impurity I) shown in the figure is unstable in the reaction solution and easily forms Figure 3 The product containing 9-phenylene thioxanthanol structure (impurity II) shown in the figure will form a capping group after entering into the polyetherketoneketone polymerization. The 9-phenylene thioxanthanol structure has poor thermal stability at high temperatures and is prone to cause branching and cross-linking during the polyetherketoneketone molding process.

[0004] Chinese patent CN110621647B discloses a method for manufacturing 1,4-bis(4-phenoxybenzoylbenzene) under supersaturated conditions. When o-dichlorobenzene is used as a solvent, terephthaloyl chloride and diphenyl ether react in a reaction solvent and in the presence of a Lewis acid. In the reaction, when the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex is dissolved in the reactant mixture in the reaction solution at a concentration exceeding the saturation limit, it is in a supersaturated state. However, the supersaturated state is metastable. If a nucleating agent is present in the reaction mixture, the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex in a supersaturated state can suddenly precipitate, and the precipitate will wrap part of the acyl chloride group, resulting in incomplete reaction and affecting the overall yield. The patent adopts some restrictive methods to prevent or delay the nucleation of the precipitate, thereby improving the yield. However, the amount of aluminum trichloride used in the patent is relatively large. After the reaction reaches a certain level, the undissolved aluminum trichloride easily forms crystal nuclei, resulting in the precipitation of 1,4-bis(4-phenoxybenzoyl)benzene-Lewis complex, making the overall reaction control difficult. On the other hand, increasing the temperature accelerates the reaction rate, which easily forms polymers, affecting the overall yield and product quality. Therefore, it is also necessary to provide a preparation method of 1,4-bis(4-phenoxybenzoyl)benzene with high yield and simple operation. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a high-yield 1,4-bis(4-phenoxybenzoyl)benzene synthesis process. The high-yield 1,4-bis(4-phenoxybenzoyl)benzene synthesis process provided by the present invention is simple to operate, not only significantly improves the yield of the target compound, but also ensures the high purity and low impurity content of the product.

[0006] The technical solution of the present invention is:

[0007] Provided is a high-yield 1,4-bis(4-phenoxybenzoyl)benzene synthesis process, which is mainly prepared by using excess diphenyl ether and terephthaloyl chloride as reaction raw materials, using o-dichlorobenzene as reaction solvent, and under the catalytic action of aluminum chloride. The specific preparation process includes the following steps:

[0008] (1) Using o-dichlorobenzene as solvent, prepare a mixture of terephthaloyl chloride and diphenyl ether, fully dissolve them and set aside;

[0009] (2) Add o-dichlorobenzene and part of aluminum trichloride into the reaction flask, stir, and cool to -10 to -5°C, then drop the mixed solution prepared in step (1) into the reaction flask, and keep the reaction for a while after the dropwise addition is completed;

[0010] (3) Add the remaining aluminum chloride into the reaction bottle in two batches, continue to react at -10~-5℃ for a period of time, then raise the temperature in the reaction bottle to 30~35℃, continue to react until no gas is released, and the reaction is completed;

[0011] (4) contacting the liquid in the reaction flask with a protic solvent, and filtering to obtain a crude solid 1,4-bis(4-phenoxybenzoyl)benzene;

[0012] (5) Recrystallizing the crude solid 1,4-bis(4-phenoxybenzoyl)benzene obtained in step (4) to obtain purified 1,4-bis(4-phenoxybenzoyl)benzene.

[0013] Furthermore, the total mass of o-dichlorobenzene added in step (1) and step (2) is 4.5 to 7.5 times the total mass of diphenyl ether and p-diformyl chloride in step (1).

[0014] Furthermore, in the step (1), the amount of o-dichlorobenzene added is 2.0 to 3.0 times the total mass of diphenyl ether and terephthaloyl chloride.

[0015] Furthermore, in the step (1), the molar ratio of terephthaloyl chloride to diphenyl ether is 1:2.3-3.5.

[0016] Furthermore, in step (2) and step (3), the molar ratio of the total amount of aluminum trichloride to terephthaloyl chloride is 2.2 to 3.5:1.

[0017] Furthermore, the amount of aluminum chloride added in step (2) is greater than 1 / 2 of the molar amount of terephthaloyl chloride in step (1) and less than 2 times the molar amount of terephthaloyl chloride.

[0018] Furthermore, the dripping process of the mixed solution in step (2) is as follows: controlling the dripping speed of the mixed solution to maintain the temperature change in the reaction bottle within ±1°C per minute; when the temperature in the reaction bottle hardly changes during the dripping process, increasing the dripping speed until the addition is completed, and then reacting for 30 to 60 minutes.

[0019] Furthermore, in step (3), the remaining aluminum chloride is evenly divided into two portions and added to the reaction bottle in batches, each time reacting for 30 to 40 minutes, and the reaction temperature is maintained at -10 to -5°C. After the reaction is completed, the temperature in the reaction bottle is raised to 30 to 35°C, and the reaction is continued until no gas is released, and the reaction is completed.

[0020] Furthermore, the protic solvent in step (4) is one of water or hydrochloric acid solution; the amount of the protic solvent added is 0.8 to 2 times the total amount of o-dichlorobenzene.

[0021] Furthermore, the concentration of the hydrochloric acid solution is less than 5%.

[0022] Furthermore, the solvent used for recrystallization in step (5) is one of o-dichlorobenzene and N,N-dimethylformamide.

[0023] The present invention provides a high-yield 1,4-bis(4-phenoxybenzoyl)benzene synthesis process, first, select o-dichlorobenzene as a reaction solvent, and prepare a mixed solution of terephthaloyl chloride and diphenyl ether; then, under low temperature conditions (-10 to -5°C), add a portion of aluminum trichloride prepared in advance and o-dichlorobenzene into a reaction bottle; then, slowly drop the mixed solution to react, and add the remaining aluminum trichloride in batches to maintain the reaction conditions. In the whole process, an efficient and stable reaction process is achieved by adjusting the sample addition order, controlling the reaction temperature, optimizing the raw material ratio, and extending or shortening the reaction time.

[0024] In order to improve the yield of 1,4-bis(4-phenoxybenzoyl)benzene, the present invention realizes the smooth progress of the reaction by controlling the degree of reaction. Only an appropriate amount of aluminum chloride is added at the initial stage of the reaction. At the same time, the reaction is smoothly controlled by controlling the dripping method, so that the hydrogen chloride generated in the reaction is released smoothly, avoiding the reaction speed caused by excessive catalyst and the unsmooth reaction caused by the untimely release of hydrogen chloride. In addition, the remaining aluminum chloride is added in batches to ensure that each newly added catalyst can fully play its role, thereby promoting a higher conversion rate, which not only promotes the smooth progress of the main reaction, but also avoids the unsmooth reaction caused by excessive catalyst concentration. The final results show that the process of the present invention significantly improves the yield of the target compound, and its purity reaches a very high level, with extremely low impurity content, which is a significant improvement over traditional methods.

[0025] More importantly, the present invention has found in the research and development process that the solubility of the complex of 1,4-bis(4-phenoxybenzoyl)benzene and aluminum chloride in o-dichlorobenzene increases with the decrease of the ratio of aluminum chloride to 1,4-bis(4-phenoxybenzoyl)benzene, but even so, in the process of preparing 1,4-bis(4-phenoxybenzoyl)benzene, the content of aluminum chloride is reduced, and 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex will still precipitate during the reaction. At the same time, the present invention has also found in the experimental process that the precipitation of 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex is accompanied by heat release and release of hydrogen chloride gas in a short period of time, so the precipitation of 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex is not only caused by the solubility of 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex in o-dichlorobenzene, but also related to the stability of the reaction, especially the stable release of hydrogen chloride gas during the reaction. Therefore, in the synthesis process of the present invention, when the mixed solution of diphenyl ether and terephthaloyl chloride monomers is dripped into the o-dichlorobenzene solution containing aluminum chloride to prepare 1,4-bis(4-phenoxybenzoyl)benzene, the temperature during the reaction is basically kept constant (the temperature change in the reaction bottle per minute is kept within ±1°C during the specific experiment), thereby controlling the stability of the entire reaction process. As long as the reaction is carried out smoothly during the monomer dripping process, even if aluminum chloride is added later after the monomer dripping is completed, it will not cause an imbalance in the reaction stability and will not cause the precipitation of 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex.

[0026] Therefore, the present invention can achieve a smooth reaction of 1,4-bis(4-phenoxybenzoyl)benzene by controlling the reaction process, so that the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex is not easily precipitated in the reaction system, thereby improving the overall reaction yield.

[0027] Compared with the prior art, the high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene provided by the present invention has the following advantages:

[0028] The present invention provides a simple and efficient synthesis process for 1,4-bis(4-phenoxybenzoyl)benzene, which not only significantly improves the yield of the target compound, but also ensures the high purity and low impurity content of the product. The synthesis process of the present invention successfully overcomes many challenges existing in traditional synthesis methods, such as many side reactions, low yield, and difficult purification, by optimizing key parameters such as reaction conditions, solvent selection, catalyst dosage, and sample addition sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The chemical reaction formula is that terephthaloyl chloride and diphenyl ether react under the catalysis of Lewis acid to generate 1,4-bis(4-phenoxybenzoyl)benzene through Friedel-Crafts acylation;

[0030] Figure 2 It is an impurity produced during the reaction of terephthaloyl chloride and diphenyl ether to produce 1,4-bis(4-phenoxybenzoyl)benzene;

[0031] Figure 3 It is an impurity containing a 9-phenylene xanthanol structure produced during the reaction of terephthaloyl chloride and diphenyl ether to produce 1,4-bis(4-phenoxybenzoyl)benzene;

[0032] Figure 4 This is a liquid phase spectrum of the reaction solution tested after the reaction in step (3) of Example 2 is completed;

[0033] Figure 5 This is a liquid phase spectrum of the reaction solution tested after the reaction of step (3) in comparative example 1 is completed;

[0034] Figure 6 The NMR spectrum of 1,4-bis(4-phenoxybenzoyl)benzene obtained in Example 2 of the present invention (using deuterated trifluoroacetic acid and deuterated chloroform in a ratio of 1:1 as solvent). DETAILED DESCRIPTION

[0035] The present invention is further illustrated below through the description of specific implementation methods, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the protection scope of the present invention.

[0036] In the following examples and comparative examples, reagents not otherwise specified are conventional reagents and can be purchased from conventional reagent production and sales companies. The methods used are all prior art unless otherwise specified.

[0037] Example 1

[0038] A high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene, specifically comprising the following steps:

[0039] (1) Place 234.9 g of diphenyl ether and 121.8 g of terephthaloyl chloride in a single-necked bottle, add 800 g of o-dichlorobenzene, and dissolve them fully for later use;

[0040] (2) In a 2000 mL three-necked flask, add 950 g of o-dichlorobenzene and 80 g of aluminum chloride, stir evenly, then lower the temperature in the reaction flask to -5°C, and use a peristaltic pump to pump the mixed solution prepared in step (1) into the reaction flask. When the pumping starts, the temperature in the reaction flask rises. Control the feeding speed of the peristaltic pump to keep the temperature change in the reaction flask within ±1°C per minute. When the temperature in the reaction flask hardly changes, speed up the peristaltic pump to increase the dripping speed. The dripping is completed in 3.4 h. After the completion of the dripping, keep the temperature at -5°C for 30 min.

[0041] (3) Then, add 52 g of aluminum trichloride to the reaction bottle, keep the temperature at -5°C for 30 min, then add another 52 g of aluminum trichloride, keep the temperature at -5°C for 30 min, then raise the temperature to 30°C and keep the temperature for 2 h until no gas is released, and the reaction is complete;

[0042] (4) Pour 3000 g of a 3% dilute hydrochloric acid aqueous solution into the mixture in the reaction flask and stir thoroughly to allow the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex to completely decomplex, evaporate o-dichlorobenzene and diphenyl ether, then wash the remaining solid with hot water for multiple times and filter to obtain a crude 1,4-bis(4-phenoxybenzoyl)benzene;

[0043] (5) Recrystallizing the crude solid 1,4-bis(4-phenoxybenzoyl)benzene obtained in step (4) with o-dichlorobenzene to obtain purified 1,4-bis(4-phenoxybenzoyl)benzene.

[0044] Example 2

[0045] A high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene, specifically comprising the following steps:

[0046] (1) Place 255.3 g of diphenyl ether and 121.8 g of terephthaloyl chloride in a single-necked bottle, add 800 g of o-dichlorobenzene, and dissolve them fully for later use;

[0047] (2) In a 2000 mL three-necked flask, add 950 g of o-dichlorobenzene and 80 g of aluminum chloride, stir evenly, then lower the temperature in the reaction flask to -6°C, and use a peristaltic pump to pump the mixed solution prepared in step (1) into the reaction flask. When the pumping starts, the temperature in the reaction flask rises. Control the feeding speed of the peristaltic pump to keep the temperature change in the reaction flask within ±1°C per minute. When the temperature in the reaction flask hardly changes, speed up the peristaltic pump to increase the dripping speed. The dripping is completed in 3.4 h. After the completion of the dripping, keep the temperature at -6°C for 30 min.

[0048] (3) Then add 52 g of aluminum trichloride to the reaction bottle, keep the temperature at -6°C for 30 min, then add another 52 g of aluminum trichloride, keep the temperature at -6°C for 30 min, then raise the temperature to 31°C and keep the temperature for 2 h until no gas is released, and the reaction is complete. At this time, take the reaction solution for liquid chromatography detection, and the liquid phase spectrum is as follows: Figure 4 As shown;

[0049] (4) Pour 3000 g of a 3% dilute hydrochloric acid aqueous solution into the mixture in the reaction flask and stir thoroughly to completely decomplex the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex, evaporate o-dichlorobenzene and diphenyl ether, then wash the remaining solid with hot water for several times and filter to obtain a crude 1,4-bis(4-phenoxybenzoyl)benzene;

[0050] (5) Recrystallizing the crude solid 1,4-bis(4-phenoxybenzoyl)benzene obtained in step (4) with o-dichlorobenzene to obtain purified 1,4-bis(4-phenoxybenzoyl)benzene.

[0051] Example 3

[0052] A high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene, specifically comprising the following steps:

[0053] (1) Place 306.3 g of diphenyl ether and 121.8 g of terephthaloyl chloride in a single-necked bottle, add 1100 g of o-dichlorobenzene, and dissolve them fully for later use;

[0054] (2) In a 2000 mL three-necked flask, add 1700 g of o-dichlorobenzene and 120 g of aluminum chloride, stir evenly, then lower the temperature in the reaction flask to -7°C, and use a peristaltic pump to pump the mixed solution prepared in step (1) into the reaction flask. When the pumping starts, the temperature in the reaction flask rises. Control the feeding speed of the peristaltic pump to keep the temperature change in the reaction flask within ±1°C per minute. When the temperature in the reaction flask hardly changes, speed up the peristaltic pump to increase the dripping speed. The dripping is completed in 3.8 h. After the completion of the dripping, keep the temperature at -7°C for 40 min.

[0055] (3) Then add 60 g of aluminum chloride to the reaction bottle, keep the temperature at -7°C for 35 min, then add another 60 g of aluminum chloride, keep the temperature at -7°C for 35 min, then raise the temperature to 33°C and keep the temperature for 2 h until no gas is released, and the reaction is complete;

[0056] (4) Pour 4000 g of a 3% dilute hydrochloric acid aqueous solution into the mixture in the reaction flask and stir thoroughly to completely decomplex the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex, evaporate o-dichlorobenzene and diphenyl ether, then wash the remaining solid with hot water for several times, filter, and obtain a crude 1,4-bis(4-phenoxybenzoyl)benzene;

[0057] (5) Recrystallizing the crude solid 1,4-bis(4-phenoxybenzoyl)benzene obtained in step (4) with o-dichlorobenzene to obtain purified 1,4-bis(4-phenoxybenzoyl)benzene.

[0058] Example 4

[0059] A high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene, specifically comprising the following steps:

[0060] (1) Place 326.8 g of diphenyl ether and 121.8 g of terephthaloyl chloride in a single-necked bottle, add 1100 g of o-dichlorobenzene, and dissolve them fully for later use;

[0061] (2) In a 2000 mL three-necked flask, add 1700 g of o-dichlorobenzene and 100 g of aluminum chloride, stir evenly, then lower the temperature in the reaction flask to -8°C, and use a peristaltic pump to pump the mixed solution prepared in step (1) into the reaction flask. When the pumping starts, the temperature in the reaction flask rises. Control the feeding speed of the peristaltic pump to keep the temperature change in the reaction flask within ±1°C per minute. When the temperature in the reaction flask hardly changes, speed up the peristaltic pump to increase the dripping speed. The dripping is completed in 4 hours. After the completion of the dripping, keep the temperature at -8°C for 50 minutes.

[0062] (3) Then, add 78 g of aluminum trichloride to the reaction bottle, keep the temperature at -8°C for 40 min, then add another 78 g of aluminum trichloride, keep the temperature at -8°C for 40 min, then raise the temperature to 34°C and keep the temperature for 2 h until no gas is released, and the reaction is complete;

[0063] (4) Pour 3000 g of a 3% dilute hydrochloric acid aqueous solution into the mixture in the reaction flask and stir thoroughly to allow the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex to completely decomplex, evaporate o-dichlorobenzene and diphenyl ether, then wash the remaining solid with hot water for multiple times and filter to obtain a crude 1,4-bis(4-phenoxybenzoyl)benzene;

[0064] (5) Recrystallizing the crude solid 1,4-bis(4-phenoxybenzoyl)benzene obtained in step (4) from N,N-dimethylformamide to obtain purified 1,4-bis(4-phenoxybenzoyl)benzene.

[0065] Example 5

[0066] A high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene, specifically comprising the following steps:

[0067] (1) Place 357.4 g of diphenyl ether and 121.8 g of terephthaloyl chloride in a single-necked bottle, add 1200 g of o-dichlorobenzene, and dissolve them fully for later use;

[0068] (2) In a 2000 mL three-necked flask, add 1800 g of o-dichlorobenzene and 130 g of aluminum chloride, stir evenly, then lower the temperature in the reaction flask to -10°C, and use a peristaltic pump to pump the mixed solution prepared in step (1) into the reaction flask. When the pumping starts, the temperature in the reaction flask rises. Control the feeding speed of the peristaltic pump to keep the temperature change in the reaction flask within ±1°C per minute. When the temperature in the reaction flask hardly changes, increase the feeding speed of the peristaltic pump. The addition is completed in 4 hours. After the addition is completed, keep the temperature at -10°C for 60 minutes.

[0069] (3) Then add 75 g of aluminum trichloride to the reaction bottle, keep the temperature at -10°C for 40 min, then add another 75 g of aluminum trichloride, keep the temperature at -10°C for 40 min, then raise the temperature to 35°C and keep the temperature for 2 h until no gas is released, and the reaction is complete;

[0070] (4) Pour 3000 g of a 3% dilute hydrochloric acid aqueous solution into the mixture in the reaction flask and stir thoroughly to allow the 1,4-bis(4-phenoxybenzoyl)benzene-Lewis acid complex to completely decomplex, evaporate o-dichlorobenzene and diphenyl ether, then wash the remaining solid with hot water for multiple times and filter to obtain a crude 1,4-bis(4-phenoxybenzoyl)benzene;

[0071] (5) Recrystallizing the crude solid 1,4-bis(4-phenoxybenzoyl)benzene obtained in step (4) from N,N-dimethylformamide to obtain purified 1,4-bis(4-phenoxybenzoyl)benzene.

[0072] Comparative Example 1

[0073] Compared with Example 2, the difference is that the specific operation of step (2) is as follows: 950 g of o-dichlorobenzene and 80 g of aluminum chloride are added to a 2000 mL three-necked flask, and the mixture is stirred evenly. Then, the temperature in the reaction flask is lowered to -6°C, and the mixed solution prepared in step (1) is pumped into the reaction flask by a peristaltic pump. When the pumping starts, the temperature in the reaction flask rises. The feeding speed of the peristaltic pump is controlled to keep the temperature change in the reaction flask within ±5°C per minute. When the temperature in the reaction flask hardly changes, the feeding speed of the peristaltic pump is increased. The addition is completed in 2.5 h. After the addition is completed, the temperature is maintained at -6°C for 30 min.

[0074] The other step parameters and operations are the same as those in Example 2. After the reaction in step (3) is completed, the reaction solution is subjected to liquid chromatography to obtain a liquid phase spectrum as shown in FIG. Figure 5 shown.

[0075] Comparative Example 2

[0076] Compared with Example 2, the difference is that the reaction temperature when adding aluminum chloride in batches in step (3) is controlled at 30°C, that is, the specific process of step (3) is: add 52 g of aluminum chloride to the reaction bottle, keep the temperature at 30°C for 30 minutes, then add 52 g of aluminum chloride, continue to keep the temperature at 30°C for 2 hours until no gas is released, and the reaction is completed. Other step parameters and operations are the same as those in Example 2.

[0077] Comparative Example 3

[0078] Compared with Example 2, the difference is that in step (3), all the remaining aluminum chloride is directly added without adding in batches, that is, the specific process of step (3) is: add 104 g of aluminum chloride to the reaction bottle, continue to maintain the temperature of -6°C for 60 min, then raise the temperature to 30°C, keep the temperature for 2 h until no gas is released, and the reaction is completed. Other step parameters and operations are the same as those in Example 2.

[0079] Comparative Example 4

[0080] Refer to the process of the embodiment in Chinese patent CN110621647B.

[0081] Test example:

[0082] After the reaction was completed, the yield, purity and by-product content of 1,4-bis(4-phenoxybenzoyl)benzene prepared in Examples 1 to 5 of the present invention and Comparative Examples 1 to 4 were statistically analyzed, and the results are shown in Table 1.

[0083] Table 1

[0084] Group Yield after recrystallization (%) 1,4-bis(4-phenoxybenzoyl)benzene(EKKE) content (%) Monoacyl chloride content (%) Ortho group (including thiophene structure) content (%) Example 1 93.6 96.24 0.071 3.69 Example 2 93.8 96.25 0.082 3.67 Example 3 94.1 96.74 0.052 3.21 Example 4 93.5 96.26 0.016 3.72 Example 5 93.5 96.14 0.03 3.83 Comparative Example 1 82.9 85.28 10.86 3.86 Comparative Example 2 82.2 85.56 10.80 3.64 Comparative Example 3 83.1 86.20 10.24 3.56 Comparative Example 4 82.6 85.32 11.20 3.48

[0085] As shown in Table 1, the yield of 1,4-bis(4-phenoxybenzoyl)benzene obtained by the synthesis process of Examples 1 to 5 of the present invention is above 93%, and the content is above 95%, and the content of monoacyl chloride is low, indicating that the synthesis process provided by the present invention not only significantly improves the yield of the target compound, but also ensures the high purity and low impurity content of the product. When certain steps in the synthesis process are changed in Comparative Examples 1 to 3, the yield and content of the obtained 1,4-bis(4-phenoxybenzoyl)benzene have a significant decrease, and the impurity content increases.

[0086] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene, characterized in that: The method comprises the following preparation steps: (1) Using o-dichlorobenzene as solvent, prepare a mixture of terephthaloyl chloride and diphenyl ether, fully dissolve them and set aside; (2) Add o-dichlorobenzene and part of aluminum trichloride into the reaction flask, stir, and cool to -10 to -5°C, then drop the mixed solution prepared in step (1) into the reaction flask, and keep the reaction for a while after the dropwise addition is completed; (3) Add the remaining aluminum chloride into the reaction bottle in two batches, continue to react at -10~-5℃ for a period of time, then raise the temperature in the reaction bottle to 30~35℃, continue to react until no gas is released, and the reaction is completed; (4) contacting the liquid in the reaction flask with a protic solvent, and filtering to obtain a crude solid 1,4-bis(4-phenoxybenzoyl)benzene; (5) recrystallizing the crude solid 1,4-bis(4-phenoxybenzoyl)benzene obtained in step (4) to obtain purified 1,4-bis(4-phenoxybenzoyl)benzene; The process of adding the mixed solution dropwise in step (2) is as follows: controlling the dropping speed of the mixed solution to keep the temperature change in the reaction bottle within ±1°C per minute; when the temperature in the reaction bottle remains unchanged during the dropping process, increasing the dropping speed until the addition is completed, and then reacting for 30 to 60 minutes; In the steps (2) and (3), the molar ratio of the total amount of aluminum chloride to terephthaloyl chloride is 2.2 to 3.5:1; The amount of aluminum chloride added in step (2) is greater than 1 / 2 of the molar amount of terephthaloyl chloride in step (1) and less than 2 times the molar amount of terephthaloyl chloride; In the step (3), the remaining aluminum chloride is evenly divided into two portions and added to the reaction bottle in batches. Each addition is reacted for 30 to 40 minutes, and the reaction temperature is maintained at -10 to -5°C.

2. The high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene according to claim 1, characterized in that: The total mass of o-dichlorobenzene added in step (1) and step (2) is 4.5 to 7.5 times the total mass of diphenyl ether and p-diformyl chloride in step (1).

3. The high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene according to claim 1, characterized in that: The amount of o-dichlorobenzene added in step (1) is 2.0 to 3.0 times the total mass of diphenyl ether and terephthaloyl chloride.

4. The high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene according to claim 1, characterized in that: In the step (1), the molar ratio of terephthaloyl chloride to diphenyl ether is 1:2.3-3.

5.

5. The high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene according to claim 1, characterized in that: The protic solvent in step (4) is one of water or hydrochloric acid solution; the amount of the protic solvent added is 0.8 to 2 times the total amount of o-dichlorobenzene, and the concentration of the hydrochloric acid solution is less than 5%.

6. The high-yield synthesis process of 1,4-bis(4-phenoxybenzoyl)benzene according to claim 1, characterized in that: The solvent used for recrystallization in step (5) is one of o-dichlorobenzene and N,N-dimethylformamide.

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