The invention relates to 4, 4apos; -bis ((4-vinylphenoxy) methyl)-1, 1apos; synthesis method of-biphenyl

Abstract

The invention relates to the technical field of organic synthesis, in particular to a synthetic method of 4, 4 '-bis ((4-vinylphenoxy) methyl)-1, 1'-biphenyl, which comprises the following steps: S1, adding p-hydroxycinnamic acid, a polymerization inhibitor and an alkaline reagent into an organic solvent, and heating for dehydration reaction to convert p-hydroxycinnamic acid into p-hydroxystyrene; s2, cooling the reaction system in the S1 to room temperature, adding inorganic alkali and dichlorobenzyl biphenyl, carrying out ice-bath reaction, after the reaction is finished, adding water into the reaction system for multiple times, and carrying out filtration (preferably suction filtration), so as to obtain a crude product of 4, 4 '-bis ((4-vinyl phenoxy) methyl)-1, 1'-biphenyl; and S3, fully dissolving the crude product prepared in S2 by using an organic solvent, filtering (preferably performing suction filtration) to obtain a filtrate which is a solution containing 4, 4 '-bis ((4-vinyl phenoxy) methyl)-1, 1'-biphenyl, and crystallizing the solution to obtain the 4, 4 '-bis ((4-vinyl phenoxy) methyl)-1, 1'-biphenyl. The synthesis method is mild in condition, reliable and controllable in reaction, few in side reaction and high in product yield.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for synthesizing a polymer resin monomer 4,4'-bis((4-vinylphenoxy)methyl)-1,1'-biphenyl. Background Art

[0002] Electronic materials refer to materials used in electronic technology and microelectronic technology, including dielectric materials, semiconductor materials, piezoelectric and ferroelectric materials, printed circuit materials and display materials. The main components of photoresists include photoinitiators, photosensitive resins, solvents, monomers and additives. Photosensitive resins are the basic skeleton of photoresists and also determine the basic properties of photoresists after exposure. The current film-forming resins are roughly divided into three categories: (meth) acrylate system, cycloolefin system, and maleic anhydride system. The skeleton of cycloolefin polymers is a polycyclic aliphatic ring structure with strong corrosion resistance and high light transmittance, making them one of the ideal materials for photoresists. Among the photoelectric resist dry films, there is a class of p-hydroxystyrene polymers. Because the compound contains a large number of benzene rings, it has a strong anti-dry etching ability. Photoelectric resist dry films are usually electronic grade resins, which are mainly used in fine graphics processing such as display panels and semiconductor discrete devices. At present, most of the photoelectric resist dry films used in my country's photolithography technology, especially high-end products, rely on imports, and it is urgent to carry out independent research and development to improve the efficiency of domestic production.

[0003] 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl is a structural extension of p-hydroxystyrene. It has a double benzene ring structure. As a derivative of p-hydroxystyrene, it can play a variety of roles in photoresist dry film (PDF), especially in terms of photosensitivity and cross-linking properties. The vinyl group in the compound can participate in free radical polymerization under ultraviolet light and cross-link with other monomers or resins containing unsaturated bonds to form a three-dimensional network structure. This helps to increase the mechanical strength, chemical stability and dimensional stability of the film. The compound contains a phenoxy group, which makes the compound have a strong interaction with the substrate surface, thereby improving the adhesion of the anti-etching dry film to substrates of different materials, ensuring that it will not easily peel off in subsequent etching and other processes. Therefore, broadening the synthesis method of the resin monomer 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl is conducive to breaking through the manufacturing bottleneck of electronic materials and has great research benefits. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, wherein p-hydroxycinnamic acid and biphenyl dichlorobenzyl are used as raw materials for reaction to obtain 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The compound can be used as a polymer monomer of a new photoelectric resist dry film and used for modifying the photoelectric resist dry film, which is conducive to breaking through the manufacturing bottleneck of electronic materials.

[0006] (II) Technical solution

[0007] In a first aspect, the present invention provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, comprising the following steps:

[0008] S1, adding p-hydroxycinnamic acid, a polymerization inhibitor and an alkaline agent to an organic solvent, raising the temperature to carry out a dehydration reaction, so that the p-hydroxycinnamic acid is converted into p-hydroxystyrene;

[0009] S2, cooling the reaction system of S1 to room temperature, adding an inorganic base and biphenyl dichlorobenzyl, reacting in an ice bath, and after the reaction is completed, adding water to the reaction system for multiple times and filtering (preferably suction filtration) to obtain a crude product of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl;

[0010] S3. The crude product prepared in S2 is fully dissolved in an organic solvent and filtered (preferably by suction). The filtrate is a solution containing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The solution is crystallized to obtain 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl.

[0011] According to a preferred embodiment of the present invention, in S1, the organic solvent is at least one of toluene and N,N-dimethylformamide.

[0012] According to a preferred embodiment of the present invention, in S1, the alkaline agent is an inorganic base or an alkaline salt, and the alkaline salt is at least one of anhydrous potassium carbonate, anhydrous potassium acetate or anhydrous sodium carbonate.

[0013] Since p-hydroxystyrene is very unstable, side reactions such as self-polymerization or other unexpected chemical changes are likely to occur under strong alkaline conditions (such as the high pH environment provided by potassium hydroxide), because strong bases can promote certain types of reactions, especially for compounds containing active hydrogen or easily forming negative ions. The use of weaker alkaline salts such as anhydrous potassium carbonate, anhydrous potassium acetate or anhydrous sodium carbonate can provide sufficient alkalinity to promote the dehydration reaction while reducing side reactions caused by excessive alkalinity, which helps to improve the selectivity and yield of the target product. The alkalinity provided by potassium acetate and sodium carbonate is relatively mild, which is sufficient for the dehydration reaction of hydroxycinnamic acid. This mild condition is not only conducive to controlling the reaction rate, but potassium acetate, as a weak base salt, plays a buffering role and helps maintain the reaction system in a relatively stable pH range.

[0014] According to a preferred embodiment of the present invention, in S1, the polymerization inhibitor is at least one of hydroquinone, p-methoxyphenol, p-tert-butylcatechol, phenothiazine, N-nitroso-N-phenylhydroxylamine aluminum salt, dialkyl dithiocarbamate and p-benzoquinone.

[0015] Inhibitors can inhibit or slow down the occurrence of polymerization reactions by capturing free radicals or other active intermediates, thereby preventing the chain growth of polymerization reactions such as styrene and preventing self-polymerization of styrene and its derivatives.

[0016] p-Methoxyphenol MEHQ is a derivative of hydroquinone, which is more stable than pure hydroquinone and has lower volatility and toxicity. p-tert-butylcatechol TBHQ and phenothiazine Phenothiazine are highly effective antioxidants and inhibitors. N-nitroso-N-phenylhydroxylamine aluminum salt (NA-17) is particularly suitable for use under high temperature conditions and can effectively inhibit the thermally initiated polymerization of styrene and its derivatives. Dialkyl dithiocarbamates have a good inhibitory effect on polymerization reactions initiated by free radicals. p-Benzoquinone can react with free radicals to form a stable complex, thereby terminating the polymerization reaction. Under the condition that the dehydration reaction in S1 is about 150°C, the inhibitor is preferably at least one of NA-17 and phenothiazine. These two inhibitors remain highly effective at high temperatures and will not significantly interfere with the dehydration reaction itself, and their dosage is preferably 1-5% of the theoretical mass of p-hydroxycinnamic acid.

[0017] According to a preferred embodiment of the present invention, in S1, the molar ratio of p-hydroxycinnamic acid to the alkaline agent is 1:0.1-0.5, and the mass ratio of p-hydroxycinnamic acid to the inhibitor is 1:0.01-0.05.

[0018] According to a preferred embodiment of the present invention, in S1, when the organic solvent is DMF, the temperature of the dehydration reaction is 148-152°C, preferably 150°C; when the organic solvent is toluene, the temperature of the dehydration reaction is 105-110°C, preferably 110°C.

[0019] According to a preferred embodiment of the present invention, in S2, the molar ratio of p-hydroxystyrene to the inorganic base is 1:0.8-1, and the inorganic base used in step S2 is potassium hydroxide or sodium hydroxide.

[0020] According to a preferred embodiment of the present invention, in S3, the organic solvent is at least one of dichloromethane, petroleum ether and ethyl acetate, and the amount used is 4-10 times the volume of the crude product of 4,4'-bis((4-vinylphenoxy)methyl)-1,1'-biphenyl.

[0021] According to a preferred embodiment of the present invention, in S3, the treatment of crystallizing the solution includes: rotary evaporation or negative pressure volatilization of the organic solvent, recovery of the organic solvent, cooling, solid-liquid separation, anhydrous ethanol washing, drying and the like.

[0022] (III) Beneficial effects

[0023] The present invention provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, wherein p-hydroxycinnamic acid is used as a starting raw material to first prepare p-hydroxystyrene, which is then reacted with biphenyl dichlorobenzyl to obtain a crude product, and the crude product is dissolved in a good solvent and recrystallized to obtain a target product. The synthetic method of the present invention has mild conditions, reliable and controllable reactions, few side reactions, and high product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl in Example 1.

[0025] Figure 2 This is the infrared absorption spectrum of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl of Example 1. DETAILED DESCRIPTION

[0026] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0027] As shown in the chemical equation below, a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl of the present invention comprises the following steps:

[0028] S1, adding p-hydroxycinnamic acid, a polymerization inhibitor and an alkaline agent to an organic solvent, raising the temperature to carry out a dehydration reaction, so that the p-hydroxycinnamic acid is converted into p-hydroxystyrene;

[0029] S2, cooling the reaction system of S1 to room temperature, adding an inorganic base and biphenyl dichlorobenzyl, reacting in an ice bath, and after the reaction is completed, adding water to the reaction system for multiple times and filtering (preferably suction filtration) to obtain a crude product of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl;

[0030] S3. The crude product prepared in S2 is fully dissolved in an organic solvent and filtered (preferably by suction). The filtrate is a solution containing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The solution is crystallized to obtain 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl.

[0031]

[0032] The above-mentioned synthesis method starts with p-hydroxycinnamic acid instead of directly using p-hydroxystyrene as a raw material to prepare 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, which has the following technical effects: ① Availability and cost of raw materials: p-hydroxycinnamic acid: As a naturally occurring compound or an intermediate synthesized by simple chemical methods, p-hydroxycinnamic acid may be easier to obtain and has a relatively low cost. In addition, it exists in nature (such as in some plants) and can be used as part of renewable resources. p-Hydroxystyrene: In contrast, p-hydroxystyrene is a more specific chemical, and its synthesis and purification process may be more complicated, resulting in higher costs. Moreover, due to its high activity, p-hydroxystyrene is very sensitive to oxygen, light and temperature, and is prone to self-polymerization, which makes its storage and transportation more difficult. Special treatment is required during storage and transportation, which not only increases the corresponding cost, but also leads to an increase in side reactions in S2 and a decrease in the yield of the target product. ② Reaction conditions and controllability: In step S1, the addition of an inhibitor is to prevent the generated p-hydroxystyrene from self-polymerization. This method allows a small amount of p-hydroxystyrene to be generated in a controlled environment and then immediately used in the next reaction, thereby reducing the risk of self-polymerization. If commercially available p-hydroxystyrene is used directly, even if an inhibitor is added, there may still be some problems of self-polymerization or the inhibitor being antioxidant, and the concentration and type of inhibitors in commercial products may not be suitable for subsequent reaction conditions, and long-term storage may also lead to partial self-polymerization. ③ Purity and quality control: p-hydroxystyrene is generated on-site through the dehydration reaction of p-hydroxycinnamic acid, and freshly prepared products can be used directly in the reaction system, avoiding the problem of introducing impurities due to long-term storage. This helps to improve the purity and quality of the final product. ④ Process flexibility: The above scheme provides greater process flexibility, and the conditions of each step of the reaction, such as temperature, time and reagent ratio, can be adjusted according to specific needs to optimize the entire synthesis path. This flexibility is very valuable for developing new processes or improving existing processes. ⑤ Start with p-hydroxycinnamic acid through a dehydration reaction to ensure that a portion of p-hydroxystyrene is generated under controlled conditions, followed by a nucleophilic substitution reaction, and react with biphenyl dichlorobenzyl in the presence of an appropriate solvent and an inorganic base to form the target compound. This process also includes the equilibrium process in which p-hydroxycinnamic acid is continuously converted into p-hydroxystyrene, and p-hydroxystyrene is continuously converted into the target compound.

[0033] The cost of p-hydroxystyrene as a starting material is usually higher than that of p-hydroxycinnamic acid, especially when produced on a large scale. In addition, considering the need for inhibitors and other stabilization measures, the overall process cost may be higher. In summary, the synthesis of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl from p-hydroxycinnamic acid not only takes into account economy and feasibility, but also ensures the efficiency and controllability of the reaction, as well as the quality and purity of the final product. This method not only provides better reaction control, but also reduces the occurrence of side reactions and improves the purity and yield of the product. At the same time, it also meets the efficiency requirements of industrial production, reduces the trouble caused by handling unstable intermediates, and embodies the concept of "green chemistry" in chemical production, that is, to use safer and more environmentally friendly raw materials as much as possible, and to minimize waste generation and energy consumption by optimizing reaction conditions.

[0034] The following are preferred embodiments of the present invention.

[0035] Example 1

[0036] This embodiment provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, the steps of which are as follows:

[0037] (1) Into a four-necked flask equipped with a thermometer, condensation reflux and mechanical stirring, 2 g of p-hydroxycinnamic acid (12.20 mmol; molecular weight 164.16), 0.12 g of anhydrous potassium acetate (1.22 mmol), 0.02 g of phenothiazine and 20 mL of DMF were added, the temperature was raised to 150° C., and the reaction was carried out for 1.5 h to obtain a DMF reaction solution containing p-hydroxystyrene.

[0038] (2) The reaction solution was cooled to room temperature, and 0.683 g of KOH (12.20 mmol) solid and 1.53 g of diphenylbenzyl chloride (6.1 mmol) were added thereto, and stirred in an ice bath for 2.5 h. The reaction system was added with water several times and filtered to obtain a crude product of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl.

[0039] (3) The crude product is dissolved in 4 times the volume of dichloromethane, filtered to obtain a dichloromethane solution containing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, concentrated under negative pressure, and allowed to stand for crystallization to obtain a crystal. The treatment of the solution for crystallization includes: rotary evaporation or negative pressure volatilization of the organic solvent, recovery of the organic solvent, cooling, solid-liquid separation, washing with anhydrous ethanol, drying, and the like.

[0040] The crystals were subjected to nuclear magnetic resonance and infrared absorption scanning, and their nuclear magnetic resonance hydrogen spectrum was as follows Figure 1 The infrared absorption spectrum is shown in Figure 2As shown, it was confirmed that the obtained crystals were indeed 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, and the product yield was 70.27%.

[0041] Example 2

[0042] This embodiment provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, the steps of which are as follows:

[0043] (1) Into a four-necked flask equipped with a thermometer, condensation reflux and mechanical stirring, 2 g of p-hydroxycinnamic acid (12.20 mmol), 0.168 g of anhydrous potassium carbonate (1.22 mmol), 0.03 g of NA-17 and 20 mL of DMF were added, the temperature was raised to 150° C., and the reaction was carried out for 1.5 h to obtain a DMF reaction solution containing p-hydroxystyrene.

[0044] (2) The reaction solution was cooled to room temperature, and 0.683 g of KOH (12.20 mmol) solid and 1.53 g of diphenylbenzyl chloride (6.1 mmol) were added thereto, and stirred in an ice bath for 2.5 h. The reaction system was added with water several times and filtered to obtain a crude product of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl.

[0045] (3) The crude product was dissolved in 5 volumes of dichloromethane, filtered to obtain a dichloromethane solution containing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, concentrated under negative pressure, and allowed to stand for crystallization to obtain 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The product yield was 65.36%.

[0046] Example 3

[0047] This embodiment provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, the steps of which are as follows:

[0048] (1) Into a four-necked flask equipped with a thermometer, condensation reflux and mechanical stirring, 2 g of p-hydroxycinnamic acid (12.20 mmol), 0.12 g of anhydrous potassium acetate (1.22 mmol), 0.02 g of NA-17 and 20 mL of toluene were added, the temperature was raised to 110° C., and the reaction was carried out for 2 h to obtain a toluene reaction solution containing p-hydroxystyrene.

[0049] (2) The reaction solution was cooled to room temperature, and 0.488 g of NaOH (12.20 mmol) solid and 1.53 g of diphenylbenzyl chloride (6.1 mmol) were added thereto, and stirred in an ice bath for 2.5 h. The reaction system was added with water several times and filtered to obtain a crude product of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl.

[0050] (3) The crude product was dissolved in 4 volumes of ethyl acetate and filtered to obtain a dichloromethane solution containing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The solution was concentrated under negative pressure and allowed to stand for crystallization to obtain 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The yield of the product was 68.42%.

[0051] Example 4

[0052] This embodiment provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, the steps of which are as follows:

[0053] (1) Into a four-necked flask equipped with a thermometer, condensation reflux and mechanical stirring, 2 g of p-hydroxycinnamic acid (12.20 mmol), 0.12 g of anhydrous potassium acetate (1.22 mmol), 0.02 g of NA-17 and 0.02 g of phenothiazine and 35 mL of DMF were added, the temperature was raised to 148°C, and the reaction was carried out for 2 h to obtain a DMF reaction solution containing p-hydroxystyrene.

[0054] (2) The reaction solution was cooled to room temperature, and 0.683 g of KOH (12.20 mmol) solid and 1.53 g of diphenylbenzyl chloride (6.1 mmol) were added thereto, and stirred in an ice bath for 2.5 h. The reaction system was added with water several times and filtered to obtain a crude product of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl.

[0055] (3) The crude product was dissolved in 4 volumes of petroleum ether, filtered to obtain a dichloromethane solution containing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, concentrated under negative pressure, and allowed to stand for crystallization to obtain 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The product yield was 67.28%.

[0056] Example 5

[0057] This embodiment provides a method for synthesizing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, the steps of which are as follows:

[0058] (1) Into a four-necked flask equipped with a thermometer, condensation reflux and mechanical stirring, 2 g of p-hydroxycinnamic acid (12.20 mmol), 0.13 g of anhydrous sodium carbonate (1.22 mmol), 0.05 g of NA-17 and 40 mL of DMF were added, the temperature was raised to 150° C., and the reaction was carried out for 1.5 h to obtain a DMF reaction solution containing p-hydroxystyrene.

[0059] (2) The reaction solution was cooled to room temperature, and 0.488 g of NaOH (12.20 mmol) solid and 1.53 g of diphenylbenzyl chloride (6.1 mmol) were added thereto, and stirred in an ice bath for 2.5 h. The reaction system was added with water several times and filtered to obtain a crude product of 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl.

[0060] (3) The crude product was dissolved in 4 volumes of petroleum ether, filtered to obtain a dichloromethane solution containing 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl, concentrated under negative pressure, and allowed to stand for crystallization to obtain 4,4′-bis((4-vinylphenoxy)methyl)-1,1′-biphenyl. The product yield was 66.84%.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. These modifications or replacements, or the technical features in the above embodiments may be combined in the manner described in the embodiments if they do not conflict with each other, and these modifications, replacements or combinations do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synthesizing 4,4'-bis((4-vinylphenoxy)methyl)-1,1'-biphenyl, characterized in that: The steps include: S1, adding p-hydroxycinnamic acid, a polymerization inhibitor and an alkaline agent to an organic solvent, raising the temperature to carry out a dehydration reaction, so that the p-hydroxycinnamic acid is converted into p-hydroxystyrene; S2, cooling the reaction system of S1 to room temperature, adding an inorganic base and biphenyl benzyl dichloride, reacting in an ice bath, and after the reaction is completed, adding water to the reaction system for multiple times and filtering to obtain a crude product of 4,4'-bis((4-vinylphenoxy)methyl)-1,1'-biphenyl; S3. The crude product prepared in S2 is fully dissolved in an organic solvent and filtered. The filtrate is a solution containing 4,4'-bis((4-vinylphenoxy)methyl)-1,1'-biphenyl. The solution is crystallized to obtain 4,4'-bis((4-vinylphenoxy)methyl)-1,1'-biphenyl.

2. The synthesis method according to claim 1, characterized in that In S1, the organic solvent is at least one of toluene and N,N-dimethylformamide.

3. The synthesis method according to claim 1, characterized in that In S1, the alkaline agent is an inorganic base or an alkaline salt, and the alkaline salt is at least one of anhydrous potassium carbonate, anhydrous potassium acetate or anhydrous sodium carbonate.

4. The synthesis method according to claim 1, characterized in that In S1, the polymerization inhibitor is at least one of hydroquinone, p-methoxyphenol, p-tert-butylcatechol, phenothiazine, N-nitroso-N-phenylhydroxylamine aluminum salt, dialkyl dithiocarbamate and p-benzoquinone.

5. The synthesis method according to claim 4, characterized in that The polymerization inhibitor is at least one of NA-17 and phenothiazine, and the dosage of the polymerization inhibitor is 1-5% of the theoretical mass of the hydroxycinnamic acid.

6. The synthesis method according to claim 3, characterized in that In S1, the molar ratio of p-hydroxycinnamic acid to the alkaline agent is 1:0.1-0.5, and the mass ratio of p-hydroxycinnamic acid to the inhibitor is 1:0.01-0.

05.

7. The synthesis method according to claim 1, characterized in that In S1, when the organic solvent is DMF, the temperature of the dehydration reaction is 148-152°C, preferably 150°C; when the organic solvent is toluene, the temperature of the dehydration reaction is 105-110°C, preferably 110°C.

8. The synthesis method according to claim 1, characterized in that In S2, the molar ratio of p-hydroxystyrene to the inorganic base is 1:0.8-1, and the inorganic base used in step S2 is potassium hydroxide or sodium hydroxide.

9. The synthesis method according to claim 1, characterized in that In S3, the organic solvent is at least one of dichloromethane, petroleum ether and ethyl acetate, and the amount used is 4-10 times the volume of the crude product of 4,4'-bis((4-vinylphenoxy)methyl)-1,1'-biphenyl.

10. The synthesis method according to claim 1, characterized in that In S3, the crystallization treatment of the solution includes: rotary evaporation or negative pressure volatilization of the organic solvent, recovery of the organic solvent, cooling, solid-liquid separation and anhydrous ethanol washing.

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