The invention relates to 4, 4apos; -bis (4-vinylbenzyl)-1, 1apos,-bis (4-vinyl benzyl)-1, 1apos; synthesis method of-biphenyl

Abstract

The invention relates to the field of chemical synthesis, and particularly discloses a synthesis method of 4, 4 '-bis (4-vinyl benzyl)-1, 1'-biphenyl. The synthesis method comprises the following steps: S1, heating 4, 4 '-dichloromethyl biphenyl, p-vinylphenylboronic acid, an alkaline reagent and a palladium catalyst in an organic solvent to perform a coupling reaction; and S2, cooling the reaction liquid in the S1 to room temperature, then extracting, concentrating and carrying out column separation to obtain a product solution, and then evaporating the product solution to dryness to obtain the 4, 4 '-bis (4-vinylbenzyl)-1, 1'-biphenyl. According to the synthesis method, a coupling reaction mode is adopted, 4, 4 '-dichloromethyl biphenyl and p-vinylphenylboronic acid serve as raw materials, the final product can be obtained through one-step reaction under the action of the alkaline reagent and the palladium catalyst, the reaction process is simple, reaction conditions are mild, the process is reliable and controllable, and the yield and purity of the obtained product are high.

Description

Technical Field

[0001] This application relates to the field of chemical synthesis, and more specifically, to a method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl. Background Technology

[0002] Benzocyclobutene resins, as an important type of thermosetting resin, have demonstrated significant application value in numerous fields due to their unique properties. In the aerospace industry, they provide lightweight and high-strength structural materials for aircraft, contributing to improved performance and fuel efficiency. In the electronics industry, their low dielectric constant and loss factor make them ideal for manufacturing high-performance circuit boards and electronic components, enhancing the operating speed and stability of electronic devices. In the automotive, shipbuilding, and construction industries, benzocyclobutene resins have also gained widespread application due to their excellent mechanical properties and chemical stability. Biphenyl-type benzocyclobutene and its derivatives, as functionalized subclasses of benzocyclobutene resins, exhibit high reactivity due to their unique nonpolar four-membered ring chemical structure, undergoing ring-opening reactions upon heating. They can undergo addition reactions with dienophiles, leading to the preparation of highly crosslinked thermosetting polymers with various monomers. These materials can maintain suitable curing temperatures, do not release small molecules during curing, possess low dielectric constants and loss factors, and exhibit excellent overall performance, thus finding increasingly widespread application in high-frequency radio transmission, integrated circuit chip packaging, and other fields. With the rapid development of emerging technologies such as 5G communication, the Internet of Things, wearable devices, and new energy vehicles, the market demand for benzocyclobutene resins has increased dramatically, which has also driven the rapid development of the biphenyl-type benzocyclobutene and its derivatives market.

[0003] However, due to the long chain length and high reactivity of biphenyl-type benzocyclobutene and its derivatives, they are highly susceptible to homopolymerization. Therefore, existing synthetic methods for biphenyl-type benzocyclobutene and its derivatives generally suffer from long reaction steps, low yields, unstable products, and difficult purification, significantly limiting their industrial-scale production. 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl, as an important biphenyl-type benzocyclobutene monomer, has significant value in the synthesis and application of high-end resin materials. However, the traditional synthetic route for 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl involves Grignard reactions, coupling reactions, and addition reactions, resulting in lengthy steps, low yields (usually no higher than 60%), and difficult purification, requiring column chromatography or recrystallization to separate byproducts. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl.

[0005] This application provides a method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl, which adopts the following technical solution: A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl includes the following steps: S1. A coupling reaction is carried out in an organic solvent with 4,4'-dichloromethylbiphenyl, p-vinylphenylboronic acid, a basic reagent, and a palladium catalyst under elevated temperature to produce 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl; the reaction formula for this process is shown below: S2. Cool the reaction solution of S1 to room temperature, then extract, concentrate, and separate by column chromatography to obtain the product solution. Then evaporate the product solution to dryness to obtain 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl.

[0006] By adopting the above technical solution, this application uses 4,4'-dichloromethylbiphenyl and p-vinylphenylboronic acid as raw materials. Under alkaline conditions, a palladium catalyst is added and the temperature is raised to carry out a coupling reaction to obtain a reaction solution containing the product. After extraction and column separation, a solution containing the target product is obtained from the reaction solution. Then, the product solution is evaporated to dryness to obtain 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl. The 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl synthesis method provided by this application has mild reaction conditions, and the final product can be obtained in one step. The reaction process is simple, reliable and controllable, with few side reactions. The purity of the target product can reach more than 99%, which significantly improves the current situation of difficult purification of synthesized products. The 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl obtained by the synthesis method of this application can be used as a new polymer monomer for photoelectric resist dry films, which can be used to modify photoelectric resist dry films and help to overcome the manufacturing bottleneck of electronic materials.

[0007] Preferably, the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:(2.0-2.4).

[0008] By adopting the above technical solution, this application optimizes the ratio between 4,4'-dichloromethylbiphenyl and p-vinylphenylboronic acid, enabling the coupling reaction to proceed more fully, promoting the forward reaction, and improving the yield and purity of the target product. If the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is less than 1:2, the coupling reaction is insufficient, reducing the yield of the target product; if the molar ratio is greater than 1:2.4, it will not only waste raw materials but may also increase the occurrence of side reactions, reducing the purity of the product. As an example, the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid can be 1:2, 1:2.2, and 1:2.4. Experimental results show that when the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:2.2, the purity and yield of the obtained product are better.

[0009] Preferably, the amount of alkaline reagent used is 8-12% of the mass of 4,4'-dichloromethylbiphenyl.

[0010] By adopting the above technical solution, this application adds a certain amount of basic reagent to the reaction system, which helps to improve the efficiency and effect of the coupling reaction, thereby increasing the synthesis yield and product purity of 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl. If the amount of basic reagent is lower than this range, the basic reagent will be insufficient, and the reaction may be incomplete, leading to a decrease in the yield of the target product. If the amount of basic reagent is higher than this range, it may trigger more side reactions, reduce the purity of the product, and also increase the difficulty of subsequent separation and purification. As an example, the amount of basic reagent can be 8%, 10%, and 12% of the mass of 4,4'-dichloromethylbiphenyl. Experimental results show that when the amount of basic reagent is 10% of the mass of 4,4'-dichloromethylbiphenyl, the purity and yield of the obtained product are better.

[0011] Preferably, the alkaline reagent is an inorganic base or an alkaline salt.

[0012] Preferably, the alkaline salt includes at least one of anhydrous potassium carbonate, anhydrous potassium acetate, and anhydrous sodium carbonate.

[0013] By adopting the above technical solution, the basic reagent in the synthesis method of this application can be either an inorganic base or a basic salt. However, compared with inorganic bases, this application further selects a basic salt as the basic reagent, which makes the coupling reaction process milder. Simultaneously, the basic salt can also activate the palladium catalyst, promote metal transfer, neutralize byproduct acids, and control reaction selectivity in the palladium-catalyzed coupling reaction. Furthermore, it makes the product easier to separate and purify, reduces pollution, and facilitates post-processing. In addition, since 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl is unstable in water and easily undergoes self-polymerization, this application uses an anhydrous basic salt to control the water content of the system in the coupling reaction, thereby improving the yield of the target product.

[0014] Preferably, the amount of palladium catalyst used is 1-5% of the mass of p-vinylphenylboronic acid.

[0015] By adopting the above technical solution, this application optimizes the amount of palladium catalyst, providing suitable catalytic activity for the synthesis of 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl, thereby enabling the reaction to proceed efficiently while improving the yield and purity of the product. If the amount of palladium catalyst is less than 1% of the mass of p-vinylphenylboronic acid, the catalytic activity is insufficient, resulting in a slow coupling reaction rate, prolonged reaction time, reduced production efficiency, and possibly even incomplete reaction, reducing the yield. If the amount of palladium catalyst is more than 5% of the mass of p-vinylphenylboronic acid, although it can accelerate the reaction rate to some extent, it increases costs and may also trigger more side reactions, reducing the purity of the product and affecting product quality. As an example, the amount of palladium catalyst can be 1%, 2%, 3%, 4%, and 5% of the mass of p-vinylphenylboronic acid. Experimental results show that when the amount of palladium catalyst is 4% of the mass of p-vinylphenylboronic acid, the purity and yield of the obtained product are better.

[0016] Preferably, the palladium catalyst is bis(triphenylphosphine)palladium dichloride.

[0017] By adopting the above technical solution, this application further selects bis(triphenylphosphine)palladium dichloride as a palladium catalyst. Compared with other palladium catalysts, such as palladium on carbon catalysts, palladium alumina catalysts, and palladium barium sulfate, it can have better activity and selectivity in the coupling reaction of this application, effectively improving the purity and yield of the product.

[0018] Preferably, the organic solvent includes N,N-dimethylformamide and / or tetrahydrofuran, and the water content of the organic solvent is 1-5% (w / w).

[0019] By adopting the above technical solution, this application uses at least one of N,N-dimethylformamide and tetrahydrofuran as an organic solvent, and controls the water content of the organic solvent to be 1-5% (w / w), which can effectively control the water content of the system during the coupling reaction, thereby improving the yield of the target product. Specifically, since 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl is unstable in water and easily undergoes self-polymerization in water, but basic reagents cannot participate well in the reaction under completely anhydrous conditions, this application strictly controls the water content of the reaction system and quickly treats it after the reaction is completed.

[0020] Preferably, when the organic solvent is N,N-dimethylformamide, the coupling reaction temperature is 90-100℃ and the time is 7-9h; when the organic solvent is tetrahydrofuran, the coupling reaction is carried out by oil bath heating, the oil temperature is 70-85℃ and the time is 6-10h.

[0021] By adopting the above technical solution, when N,N-dimethylformamide is used as the organic solvent, a reaction temperature of 90-100℃ and a reaction time of 7-9 hours are more conducive to the smooth progress of the reaction. When tetrahydrofuran is used as the organic solvent, the reaction process is a reflux reaction, generally using oil bath heating at an oil temperature of 70-85℃ and a reaction time of 6-10 hours, which is more conducive to the smooth progress of the reaction. As an example, the oil temperature can be 70℃, 75℃, 80℃, and 85℃. Experimental results show that when the oil temperature is 75℃, the purity and yield of the obtained product are better.

[0022] Preferably, during the extraction process, water is first added to the reaction solution of S1, and then ethyl acetate is added for extraction at least 3 times, wherein the volume ratio of the reaction solution, water and ethyl acetate is 1:1:(1-3).

[0023] By adopting the above technical solution, this application first adds water to the reaction solution so that some impurities in the reaction solution dissolve in the aqueous phase, thus initially removing some impurities. Then, ethyl acetate is added for at least three extractions, which can fully extract the product and transfer the product from the aqueous phase to the ethyl acetate organic phase. By controlling the volume ratio of the reaction solution, water and ethyl acetate, the extraction effect can be guaranteed, which is beneficial to subsequent concentration and column separation operations, thereby obtaining a 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl product with high purity.

[0024] Preferably, the concentration mainly includes processes such as rotary evaporation or negative pressure evaporation of organic solvents, recovery of organic solvents, and cooling.

[0025] In summary, this application has the following beneficial technical effects: 1. The synthesis method of this application adopts a coupling reaction, using 4,4'-dichloromethylbiphenyl and p-vinylphenylboronic acid as raw materials. Under the action of alkaline reagent and palladium catalyst, the final product can be obtained in one step. The reaction process is simple, the reaction conditions are mild, the process is reliable and controllable, and the yield can reach more than 65%, which is higher than the yield of traditional synthesis routes. 2. The synthesis method of this application produces fewer byproducts, and the purity of the target product can reach over 99%, which significantly improves the current situation where the purification of synthetic products is difficult. 3. The 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl synthesized by the method of this application can be used as a new polymer monomer for photoelectric resist dry film, which can be used to modify photoelectric resist dry film and help to break through the manufacturing bottleneck of electronic materials. Attached Figure Description

[0026] Figure 1 This is the NMR spectrum of 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl obtained by the synthetic method of this application. Detailed Implementation

[0027] To better explain and facilitate understanding of this application, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0028] All raw materials used in this application are commercially available products. If the manufacturer is not specified, it means that they can be obtained from commercial channels in a conventional manner.

[0029] As shown in the following chemical reaction formula, a method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to this application includes the following steps: S1. Add 4,4'-dichloromethylbiphenyl, p-vinylphenylboronic acid, a basic reagent and a palladium catalyst to an organic solvent, and then heat to carry out a coupling reaction to generate 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl; The molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:(2.0-2.4). The amount of alkaline reagent used is 8-12% of the mass of 4,4'-dichloromethylbiphenyl; Alkaline reagents are inorganic bases or basic salts; Alkaline salts include at least one of anhydrous potassium carbonate, anhydrous potassium acetate, and anhydrous sodium carbonate; The amount of palladium catalyst used is 1-5% of the mass of p-vinylphenylboronic acid; The palladium catalyst is bis(triphenylphosphine)palladium dichloride; The organic solvents include N,N-dimethylformamide and / or tetrahydrofuran, and the water content of the organic solvents is 1-5% (w / w); When the organic solvent is N,N-dimethylformamide, the coupling reaction temperature is 90-100℃ and the time is 7-9h; when the organic solvent is tetrahydrofuran, the coupling reaction is carried out by oil bath heating at an oil temperature of 70-85℃ for 6-10h. S2. Cool the reaction solution from S1 to room temperature, then add water of equal volume to the reaction solution and ethyl acetate of 1-3 times the volume of the reaction solution for extraction to remove some impurities. Repeat at least 3 times. Then concentrate the ethyl acetate solution containing the target product and separate it by column chromatography to obtain the product solution. Then evaporate the product solution to dryness to obtain 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl.

[0030] The following are preferred embodiments of this application.

[0031] Example 1.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl includes the following steps: S1. Add 0.25 g of 4,4'-dichloromethylbiphenyl (1 mmol), 0.30 g of p-vinylphenylboronic acid (2 mmol), 0.02 g of anhydrous potassium carbonate, 0.003 g of bis(triphenylphosphine)palladium dichloride, and 30 mL of tetrahydrofuran with a water content of 1% (w / w) to a three-necked flask equipped with a thermometer, a straight condenser, and a magnetic stirrer. Then heat the flask in an oil bath until the oil temperature reaches 70°C and reflux for 8 hours to generate 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl. S2. Cool the reaction solution from S1 to room temperature, then add an equal volume of water to the reaction solution. After mixing, add twice the volume of ethyl acetate to extract three times. Combine the ethyl acetate phases, then concentrate the ethyl acetate solution containing the target product by rotary evaporation, followed by column chromatography to obtain the product solution. Evaporate the product solution to dryness to obtain white crystals. Analyze the white crystals using 1H NMR spectroscopy. The results are as follows: Figure 1 As shown.

[0032] Example 1.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from that of Example 1.1 in that the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:2.2, specifically 0.25 g (1 mmol) of 4,4'-dichloromethylbiphenyl and 0.33 g (2.2 mmol) of p-vinylphenylboronic acid, while the rest is the same as in Example 1.1.

[0033] Example 1.3 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from that of Example 1.1 in that the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:2.4, specifically 0.25 g (1 mmol) of 4,4'-dichloromethylbiphenyl and 0.36 g (2.4 mmol) of p-vinylphenylboronic acid, while the rest is the same as in Example 1.1.

[0034] Example 2.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of anhydrous potassium carbonate used is 10% of the mass of 4,4'-dichloromethylbiphenyl, specifically 0.025 g of anhydrous potassium carbonate, while the rest is the same as in Example 1.1.

[0035] Example 2.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from that in Example 1.1 in that the amount of anhydrous potassium carbonate used is 12% of the mass of 4,4'-dichloromethylbiphenyl, specifically 0.03 g of anhydrous potassium carbonate, while the rest is the same as in Example 1.1.

[0036] Example 3.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of bis(triphenylphosphine)palladium dichloride used is 2% of the mass of p-vinylphenylboronic acid, specifically 0.006 g of bis(triphenylphosphine)palladium dichloride, while the rest is the same as in Example 1.1.

[0037] Example 3.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of bis(triphenylphosphine)palladium dichloride used is 3% of the mass of p-vinylphenylboronic acid, specifically 0.009 g of bis(triphenylphosphine)palladium dichloride, while the rest is the same as in Example 1.1.

[0038] Example 3.3 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of bis(triphenylphosphine)palladium dichloride used is 4% of the mass of p-vinylphenylboronic acid, specifically 0.012 g of bis(triphenylphosphine)palladium dichloride, while the rest is the same as in Example 1.1.

[0039] Example 3.4 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of bis(triphenylphosphine)palladium dichloride used is 5% of the mass of p-vinylphenylboronic acid, specifically 0.015 g of bis(triphenylphosphine)palladium dichloride, while the rest is the same as in Example 1.1.

[0040] Example 4.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the oil temperature is 75°C, while the rest is the same as in Example 1.1.

[0041] Example 4.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the oil temperature is 80°C, while the rest is the same as in Example 1.1.

[0042] Example 4.3 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the oil temperature is 85°C, while the rest is the same as in Example 1.1.

[0043] Comparative Example 1.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from that of Example 1.1 in that the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:1.5, specifically 0.25 g (1 mmol) of 4,4'-dichloromethylbiphenyl and 0.22 g (1.5 mmol) of p-vinylphenylboronic acid, while the rest is the same as in Example 1.1.

[0044] Comparative Example 1.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from that of Example 1.1 in that the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:3, specifically 0.25 g (1 mmol) of 4,4'-dichloromethylbiphenyl and 0.44 g (3 mmol) of p-vinylphenylboronic acid, while the rest is the same as in Example 1.1.

[0045] Comparative Example 2.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of anhydrous potassium carbonate used is 5% of the mass of 4,4'-dichloromethylbiphenyl, specifically 0.013 g of anhydrous potassium carbonate, while the rest is the same as in Example 1.1.

[0046] Comparative Example 2.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of anhydrous potassium carbonate used is 15% of the mass of 4,4'-dichloromethylbiphenyl, specifically 0.038 g of anhydrous potassium carbonate, while the rest is the same as in Example 1.1.

[0047] Comparative Example 3.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the basic reagent used is KOH, while the rest is the same as in Example 1.1.

[0048] Comparative Example 3.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that anhydrous potassium carbonate is replaced with ordinary potassium carbonate, and the water content is 12-13%, while the rest is the same as in Example 1.1.

[0049] Comparative Example 4.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of bis(triphenylphosphine)palladium dichloride used is 0.5% of the mass of p-vinylphenylboronic acid, specifically 0.0015 g of bis(triphenylphosphine)palladium dichloride, while the rest is the same as in Example 1.1.

[0050] Comparative Example 4.2 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the amount of bis(triphenylphosphine)palladium dichloride used is 8% of the mass of p-vinylphenylboronic acid, specifically 0.024 g of bis(triphenylphosphine)palladium dichloride, while the rest is the same as in Example 1.1.

[0051] Comparative Examples 5.1-5.3 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from that in Example 1.1 in that bis(triphenylphosphine)palladium dichloride is replaced with palladium on carbon catalyst, palladium alumina catalyst, and palladium barium sulfate catalyst, respectively, while the rest is the same as in Example 1.1.

[0052] Comparative Example 6.1 A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl differs from Example 1.1 in that the tetrahydrofuran has a water content of 8% (w / w), while the rest is the same as in Example 1.1.

[0053] Data Analysis The purity of the 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl products obtained in the above examples and comparative examples was tested, and the yield of the products was calculated based on the mass of the obtained products. The results are shown in Table 1.

[0054] Table 1. Purity and Yield Results Based on the data in Table 1 and Figure 1 As can be seen from the content, the product obtained in Example 1.1 of this application is confirmed to be 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl, with a yield of 65.87% and a purity of 99.33%. The experimental results show that the synthesis method of this application uses 4,4'-dichloromethylbiphenyl and p-vinylphenylboronic acid as raw materials. Under the action of alkaline reagents and palladium catalysts, the final product can be obtained in one step. The reaction process is simple, the reaction conditions are mild, the process is reliable and controllable, and the yield can reach more than 65%, which is higher than the yield of traditional synthesis routes. Moreover, there are fewer by-products, and the purity of the target product can reach more than 99%. The product purity is high, which significantly improves the current situation of difficult purification of existing synthetic products.

[0055] A comparison of the data from Examples 1.1-1.3 shows that different molar ratios of 4,4'-dichloromethylbiphenyl and p-vinylphenylboronic acid affect the yield and purity of the product. Experimental data indicate that when the molar ratio of 4,4'-dichloromethylbiphenyl and p-vinylphenylboronic acid is 1:2.2, the yield and purity of the obtained product are better.

[0056] A comparison of the data between Examples 1.1 and 2.1-2.2 shows that different amounts of anhydrous potassium carbonate affect the yield and purity of the product. Experimental data indicate that when the amount of anhydrous potassium carbonate is 10% of the mass of 4,4'-dichloromethylbiphenyl, the yield and purity of the obtained product are better.

[0057] A comparison of the data from Examples 1.1 and 3.1-3.4 shows that different amounts of bis(triphenylphosphine)palladium dichloride affect the yield and purity of the product. Experimental data indicate that when the amount of bis(triphenylphosphine)palladium dichloride is 4% of the mass of p-vinylphenylboronic acid, the yield and purity of the obtained product are better.

[0058] A comparison of the data from Examples 1.1 and 4.1-4.3 shows that different oil temperatures affect the yield and purity of the product. Experimental data indicate that the yield and purity of the product are better when the oil temperature is 75°C.

[0059] A comparison of the data from Example 1.1 and Comparative Examples 1.1-1.2 shows that when the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is less than 1:2, the coupling reaction is not sufficiently carried out, resulting in lower yields and purity of the product. When the molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is greater than 1:2.4, although the yield does not drop to a low level, the occurrence of side reactions is significantly increased, and the purity of the product is significantly reduced.

[0060] A comparison of the data between Example 1.1 and Comparative Examples 2.1-2.2 shows that when the amount of anhydrous potassium carbonate is low, the reaction is incomplete, and the yield and purity of the product are both low. When the amount of anhydrous potassium carbonate is too high, although the yield does not drop to a low level, the occurrence of side reactions is significantly increased, the difficulty of separation and purification is increased, and the purity of the product is significantly reduced.

[0061] A comparison of the data between Example 1.1 and Comparative Example 3.1 shows that when an inorganic base is used as the alkaline reagent, the yield and purity of the obtained product are lower. The experimental results indicate that using an alkaline salt as the alkaline reagent can significantly improve the purity and yield of the product, while also making the reaction process milder. A comparison of the data between Example 1.1 and Comparative Example 3.2 shows that if the moisture content in the system is not properly controlled, the yield and purity of the obtained product will be significantly reduced.

[0062] A comparison of the data from Examples 1.1 and 4.1-4.2 shows that when the amount of bis(triphenylphosphine)palladium dichloride is low, the reaction is incomplete, and the yield and purity of the product are both low. When the amount of bis(triphenylphosphine)palladium dichloride is too high, although the yield does not drop to a low level, the occurrence of side reactions is significantly increased, and the purity of the product is significantly reduced.

[0063] Comparative Examples 5.1-5.3, due to the use of palladium on carbon catalyst, palladium alumina catalyst, and palladium barium sulfate as palladium catalysts, could not effectively catalyze the coupling reaction, thus failing to obtain the target product or resulting in extremely low product yields.

[0064] A comparison of the data between Example 1.1 and Comparative Example 6.1 shows that if the moisture content in the system is not properly controlled, the yield and purity of the obtained product will be significantly reduced.

[0065] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl, characterized in that, Includes the following steps: S1. A coupling reaction is carried out in an organic solvent with 4,4'-dichloromethylbiphenyl, p-vinylphenylboronic acid, a basic reagent, and a palladium catalyst under elevated temperature to produce 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl; the reaction formula for this process is shown below: S2. Cool the reaction solution of S1 to room temperature, then extract, concentrate, and separate by column chromatography to obtain the product solution. Then evaporate the product solution to dryness to obtain 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl.

2. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 1, characterized in that, The molar ratio of 4,4'-dichloromethylbiphenyl to p-vinylphenylboronic acid is 1:(2.0-2.4).

3. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 1, characterized in that, The amount of alkaline reagent used is 8-12% of the mass of 4,4'-dichloromethylbiphenyl.

4. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 3, characterized in that, The alkaline reagent is an inorganic base or an alkaline salt.

5. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 4, characterized in that, The alkaline salt includes at least one of anhydrous potassium carbonate, anhydrous potassium acetate, and anhydrous sodium carbonate.

6. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 1, characterized in that, The amount of palladium catalyst used is 1-5% of the mass of p-vinylphenylboronic acid.

7. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 6, characterized in that, The palladium catalyst is bis(triphenylphosphine)palladium dichloride.

8. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 1, characterized in that, The organic solvent includes N,N-dimethylformamide and / or tetrahydrofuran, and the water content of the organic solvent is 1-5% (w / w).

9. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 8, characterized in that, When the organic solvent is N,N-dimethylformamide, the coupling reaction temperature is 90-100℃ and the time is 7-9h; when the organic solvent is tetrahydrofuran, the coupling reaction is carried out by oil bath heating at an oil temperature of 70-85℃ for 6-10h.

10. The method for synthesizing 4,4'-bis(4-vinylbenzyl)-1,1'-biphenyl according to claim 1, characterized in that, During the extraction process, water is first added to the reaction solution of S1, and then ethyl acetate is added for extraction at least 3 times. The volume ratio of the reaction solution, water and ethyl acetate is 1:1:(1-3).

Images