3, 3 '-dihydroisoxazole biphenol as well as preparation method and application thereof

Abstract

The invention relates to 3, 3 '-dihydroisoxazole biphenol as well as a preparation method and application thereof, and the 3, 3'-dihydroisoxazole biphenol has the following structural formula. Different functional groups are introduced to biphenol, a new material is obtained, and compared with a traditional biphenol material, the novel material has better electrical conductivity, abrasion resistance, moisture resistance, cold resistance and the like, and can meet the requirements of different application scenes when used as a liquid crystal material.

Description

Technical Field

[0001] This invention relates to 3,3'-dihydroisoxazole biphenyl, its preparation method and application, and belongs to the field of new materials technology. Background Technology

[0002] The most widely used synthetic liquid crystal material (LCP) currently available is polymerized biphenyl phenol, a conductive organic polymer primarily used in the electronics, electrical engineering, and semiconductor fields. However, existing liquid crystal materials have shortcomings in conductivity, abrasion resistance, moisture resistance, and cold resistance, failing to meet the requirements of applications in harsh environments. With advancements in science and technology, there is a need for liquid crystal materials with specific application scenarios and performance requirements.

[0003] Furthermore, the development of new liquid crystal materials requires the introduction of different functional groups onto biphenyl hydroquinone. A key technological barrier to introducing these functional groups is the coupling of aromatic hydrocarbons. The classic aromatic hydrocarbon coupling reaction is the Ubbelohde coupling method, where halogenated aromatic hydrocarbons are coupled at temperatures above 150°C under copper powder catalysis. This method suffers from numerous side reactions, low yield (60%), poor product color, and difficulty in purification. Summary of the Invention

[0004] This invention first provides a 3,3'-dihydroisoxazole biphenyl hydrophenol, having the following structural formula: .

[0005] The 3,3'-dihydroisoxazole biphenyl hydrophenol with this structure exhibits excellent performance and can meet the requirements of special application scenarios and special performance.

[0006] The preparation method of 3,3'-dihydroisoxazole biphenyl hydrophenol in this invention includes the following steps: 1) 3,3-Dimethacrylate reacts with hydroxyurea, sodium methoxide, and hydrochloric acid to give intermediate BP011-1, as shown in the following reaction formula;

[0007] 2) Intermediate BP011-1 reacts with phosphorus oxychloride and water to obtain intermediate BP011-2, as shown in the following reaction formula;

[0008] 3) Intermediate BP011-2 reacts with o-chloroanisole and magnesium to give intermediate BP011-3, as shown in the following reaction formula;

[0009] 4) Intermediate BP011-3 reacts with chlorine to obtain intermediate BP011-4, as shown in the following reaction formula;

[0010] 5) Intermediate BP011-4 reacts with sodium hydroxide to obtain intermediate BP011-5, as shown in the following reaction formula;

[0011] 6) Intermediate BP011-5 reacts with hydrochloric acid to give the target product BP011, as shown in the following reaction formula. .

[0012] Furthermore, step 1) includes the following steps: 11) Sodium methoxide is dissolved in methanol as a substrate, and hydroxyurea is added to the substrate in batches, controlling the reaction temperature to not exceed 50°C; 12) After the reaction in step 11) is complete, add ethyl 3,3-dimethacrylate dropwise to the substrate, and control the reaction temperature to not exceed 40°C; 13) After the reaction in step 12) is complete, the substrate is separated into solid and liquid to obtain a filtrate. The filtrate is distilled under reduced pressure to remove methanol, water is added, and hydrochloric acid is added dropwise, while controlling the reaction temperature to not exceed 75°C. 14) After the reaction in step 13) is complete, extract with dichloromethane to obtain a dichloromethane solution containing intermediate BP011-1.

[0013] Furthermore, step 2) includes the following steps: 21) Triethylamine was added to the dichloromethane solution containing intermediate BP011-1 obtained in step 14) in one step, followed by the addition of phosphorus oxychloride, while controlling the reaction temperature to not exceed 80°C. 22) After the reaction in step 21) is complete, add water dropwise and control the reaction temperature at 30-60℃; 23) After the reaction in step 22) is complete, let it stand to separate into layers, collect the lower aqueous phase, and perform vacuum concentration and distillation to obtain intermediate BP011-2.

[0014] Furthermore, step 3) includes the following steps: 31) Magnesium strips were added to tetrahydrofuran, followed by iodine, as a substrate; 32) The intermediate BP011-2 was dissolved in tetrahydrofuran to obtain a BP011-2 tetrahydrofuran solution; 33) Add BP011-2 tetrahydrofuran solution dropwise to the substrate in step 31), and control the reaction temperature at 10-40℃; 34) After the reaction in step 33) is complete, add o-chloroanisole dropwise, controlling the reaction temperature at 40-60℃; 35) After the reaction in step 34) is complete, add hydrochloric acid dropwise, and control the reaction temperature to not exceed 60℃; 36) After the reaction in step 35) is complete, extract with dichloromethane, collect the lower organic phase, add water and then concentrate and distill under vacuum to obtain intermediate BP011-3.

[0015] Furthermore, step 4) includes the following steps: 41) The intermediate BP011-3 was dissolved in dichloroethane to obtain a BP011-3 dichloroethane solution, and water and ferric chloride were added as substrates; 42) Chlorine gas is introduced into the substrate to carry out the reaction, and the reaction temperature is controlled not to exceed 5°C; 43) After the reaction in step 42) is complete, add sodium sulfite in batches; 44) After the reaction in step 43) is complete, let it stand to separate into layers, collect the lower organic phase, add water, and then perform vacuum concentration and distillation to obtain intermediate BP011-4.

[0016] Furthermore, step 5) includes the following steps: 51) The intermediate BP011-4 was dissolved in dichloroethane to obtain a BP011-4 dichloroethane solution, which was used as a substrate; 52) After adding sodium hydroxide and palladium on carbon catalyst to the substrate, add reducing agent dropwise, and control the reaction temperature to be no lower than 30℃; 53) After the reaction in step 52) is complete, allow it to stand and separate into layers. Collect the lower organic phase to obtain a BP011-5 dichloroethane solution containing intermediate BP011-5.

[0017] Furthermore, step 6) includes the following steps: 61) Add water, hydrochloric acid, and sodium iodide to the BP011-5 dichloroethane solution, and control the reaction temperature to be no lower than 50℃; 62) After the reaction in step 61 is complete, allow it to stand and separate into layers. Collect the lower organic phase, concentrate and crystallize it to obtain the target product BP011.

[0018] Furthermore, in step 52), the reducing agent is formic acid.

[0019] This invention claims protection for the use of the above-mentioned 3,3'-dihydroisoxazole biphenyl hydroquinone in liquid crystal materials.

[0020] The advantages of this invention are as follows: By introducing different functional groups onto biphenyl, a new material is obtained that exhibits better conductivity, wear resistance, moisture resistance, and cold resistance compared to traditional biphenyl materials. As a liquid crystal material, it can meet the requirements of various application scenarios. This solves the technical problem that existing liquid crystal materials cannot be used in harsh climates or environments.

[0021] Furthermore, this invention utilizes palladium on carbon as a catalyst under alkaline conditions and adds a special reducing agent to achieve high-yield (over 85%) coupling of halogenated aromatic hydrocarbons under mild conditions. The method of this invention is low-cost and produces high-purity products, with chromatographic purity ≥99.5%, meeting the requirements of special liquid crystal materials. The material prepared using the method of this invention exhibits superior yield and quality compared to traditional processes and materials.

[0022] According to the method of this invention, the production process can be fully automated, which greatly reduces the intensity of manual labor while ensuring more stable product quality compared with traditional chemical production processes. It improves efficiency while reducing energy consumption and raw material consumption. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] The present invention synthesizes the target product according to the following steps: I. Cyclic Reaction 1) Set the integrated chiller temperature to 0℃ and secure it to a 500ml three-necked flask equipped with a mechanical stirrer and a constant pressure funnel. Add 90g of methanol, start stirring, and slowly add 90g of 30% sodium methoxide, controlling the temperature inside the flask to not exceed 50℃; 2) After adding sodium methoxide, add 33.5g of hydroxyurea in batches. During the process, control the temperature to not exceed 50℃. Visually inspect the flask to ensure all the hydroxyurea has dissolved. 3) Add 51.5g of ethyl 3,3-dimethacrylate to the constant pressure funnel. When the temperature inside the flask drops to 20℃, set the water chiller temperature to 25℃ and begin adding ethyl 3,3-dimethacrylate dropwise. During the process, control the temperature below 40℃. 4) After adding ethyl 3,3-dimethacrylate, continue the reaction at below 40°C for 2 hours; 5) Filter using a Buchner funnel, transfer the filtrate into a 500ml three-necked flask, collect the filter cake, and dispose of it centrally.

[0025] 6) Set the water bath temperature to 75℃ and the vacuum pump pressure to -0.085MPa. Concentrate the methanol under reduced pressure until no liquid is dispensed, then stop the reduced pressure distillation. 7) Add 200ml of water to the flask, cool with ice-water, add 62.5g of hydrochloric acid dropwise, and control the temperature to not exceed 75℃; 8) When the temperature in the flask drops below 40℃, add 150g of dichloroethane, stir for 15 minutes, and let stand for 15 minutes. Collect the lower layer of dichloroethane into a pre-weighed 1000ml three-necked flask. Add another 150g of dichloromethane to the upper aqueous phase and continue extraction. Repeat 3 times. 9) Collect the dichloroethane extract from four times, concentrate the dichloroethane under reduced pressure to 90°C in the flask under vacuum of -0.08 to -0.085 MPa, and then turn off the vacuum pump; 10) Weigh the contents, subtract the weight of the bottle, and take a sample for testing. Add 300g of dichloroethane, shake well, and use it for the next reaction step.

[0026] II. Chlorination reaction 1) Fix a 500ml four-necked flask in an ice bath, attach a mechanical stirrer, a 100ml constant pressure funnel, a reflux condenser, and connect the hydrogen chloride alkali absorption tubing. 2) Add the dichloroethane solution, the product from the previous step, and then add 30g of triethylamine all at once; 3) Add 55.5g of phosphorus oxychloride to the constant pressure funnel; 4) Begin adding phosphorus oxychloride dropwise. During this process, the temperature inside the flask should not exceed 80℃; 5) After adding phosphorus oxychloride, remove the ice bath and replace it with a water bath, setting the water bath temperature to 90℃; 6) Raise the temperature to 50-75℃ and maintain the reaction for 3 hours. Then cool the temperature down to below 50℃. 7) Add 200g of water dropwise. During the process, control the temperature at 30-60℃.

[0027] 8) After adding water droplets, continue the reaction at 30-60℃ for 2 hours. Turn off the stirring, let it stand for 15 minutes, and allow it to separate into layers. 9) Transfer the lower layer into a 500ml three-necked flask, and collect the upper layer in a waste solvent container for disposal.

[0028] 10) Vacuum degree -0.08~-0.085MPa, reduce pressure and concentrate until the internal temperature of the bottle reaches 90℃, then turn off the vacuum pump; 11) Set the heat transfer oil temperature to 150℃, concentrate with the oil pump, and maintain a vacuum of -0.095 to -0.098 MPa. Collect the fraction at 110-140℃ (weigh the receiving flask first). 12) Distillation complete. Weigh the receiving flask, subtract the flask weight, and take a sample for testing; 13) Add 100g of tetrahydrofuran to dissolve and use it directly in the next reaction.

[0029] III. Formative Response 1) Set the water bath temperature to 30℃, fix a 1000ml four-necked flask, and equip it with a 250ml constant pressure funnel, mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet tube; 2) Add 150g of THF and 9g of magnesium strip to the four-necked flask; 3) Open the nitrogen cylinder valve, start the stirrer, and add 0.5g of iodine; 4) When bubbles appear in the flask, add dropwise the product of the first step reaction, BP011-2-tetrahydrofuran solution. During the process, the temperature should be controlled between 10-40℃. 5) After adding the BP011-2-tetrahydrofuran solution, continue to keep the temperature at 10-40℃ for 2 hours; 6) After heating to above 40℃, add 50g of o-chloroanisole dropwise. Control the temperature at 40-60℃; 7) After adding o-chloroanisole, raise the temperature to 40-60℃ and maintain the temperature for 3 hours; 8) Cool to room temperature and add 50g of hydrochloric acid dropwise. During this process, the temperature should not exceed 60℃. 9) After adding the hydrochloric acid, continue stirring for 30 minutes, add 250g of dichloroethane, stir for 15 minutes, let stand for 15 minutes, and allow the layers to separate. 10) Transfer the lower layer to a 1000ml flask, add 100g of water, stir for 15 minutes, and let stand for 15 minutes; 11) Vacuum degree -0.08~-0.085MPa, reduce pressure and concentrate until the internal temperature of the bottle reaches 90℃, then turn off the vacuum pump; 12) Set the heat transfer oil temperature to 150℃, concentrate with the oil pump, and maintain a vacuum of -0.095 to -0.098 MPa. Collect the fraction at 110-140℃ (weigh the receiving flask first). 13) Distillation complete. Weigh the receiving flask, subtract the flask weight, and send a sample for testing. Dissolve in 250g of dichloroethane.

[0030] IV. Chlorination reaction 1) The integrated chiller has a temperature setting of -35℃, a fixed 1000ml four-necked flask, mechanical stirring, chlorination tube, thermometer, and hydrogen chloride tail gas alkaline absorption. 2) Add the reaction product from the previous step, dichloroethane-BP011-3, to the flask, along with 100 ml of water and 2.5 g of ferric chloride; 3) When the temperature inside the cylinder is <5℃, open the chlorine cylinder and begin chlorine flow. During the process, control the temperature inside the reactor to be <5℃; 4) When chlorine absorption is not obvious, take a sample for testing. If the residual amount of raw materials is ≤0.5%, the reaction is considered complete. Close the chlorine cylinder valve; 5) Add 3g of sodium sulfite in batches, stirring until no more bubbles appear; 6) Let stand for 15 minutes, separate into layers, and transfer the lower layer into a 1000ml three-necked flask; 7) Vacuum degree -0.08~-0.085MPa, concentrate under reduced pressure until the internal temperature of the bottle reaches 90℃, then turn off the vacuum pump; 8) Set the heat transfer oil temperature to 150℃, concentrate with the oil pump, and maintain a vacuum of -0.095 to -0.098 MPa. Collect the fraction at 70-100℃ (weigh the receiving flask first). 9) Distillation complete. Weigh the receiving flask, subtract the flask weight, and take a sample for testing.

[0031] V. Coupling Reaction 1) Add the product of the previous step, BP011-4-dichloroethane solution, to a 1000ml three-necked flask equipped with a mechanical stirrer, a constant pressure funnel, and a thermometer; 2) Turn on the stirrer and add 75g of the 20% sodium hydroxide solution prepared in the beaker to the flask all at once. Continue by adding 0.5g of 10% palladium on carbon, and then add 14.5g of reducing agent to the constant pressure funnel; 3) Set the water bath temperature to 90℃; 4) Once the temperature inside the flask reaches above 30°C, begin adding the reducing agent dropwise. During the process, maintain the temperature above 30°C. After adding the reducing agent, continue the reaction at this temperature for 3 hours. Take a sample for testing; if the raw material concentration is ≤0.5%, the reaction is considered complete, and the temperature should be lowered to 30°C.

[0032] 5) Filter using a Buchner funnel, collect on palladium carbon, and transfer the filtrate into a 1000ml separatory funnel; 6) Wash the lower organic phase once with 100ml of water, transfer it to a 1000ml three-necked flask, and proceed directly to the next reaction step.

[0033] VI. Hydrolysis reaction 1) Add the BP011-5 dichloroethane solution, 50g of water, 25g of hydrochloric acid, and 1g of sodium iodide to a 1000ml three-necked flask equipped with a thermometer, mechanical stirrer, and reflux condenser; 2) Set the water bath temperature to 90℃ and start heating; 3) When the temperature inside the bottle reaches above 50℃, start timing and take a sample for testing after 10 hours. When the BP011-5 residue is ≤0.5, the reaction is considered complete. Cool down to below 50℃, turn off the stirring, and let stand for 15 minutes to allow the layers to separate. 4) Transfer the lower layer into a 500ml separatory funnel and wash once with 50g of water. Transfer the lower layer into a 500ml three-necked flask.

[0034] 5) Start the water-flushing vacuum pump, adjust the vacuum level to -0.08 to -0.085 MPa, and concentrate the dichloroethane under reduced pressure until the internal temperature of the bottle reaches 90°C, then turn off the vacuum pump; 6) Cool the flask to below 50°C; 7) Add 200g of methanol. Cool to below 40℃ and stir to allow crystals to precipitate for 10 hours. 8) Filter the filter using a Buchner funnel, dry the filter cake in a vacuum oven at 80°C, weigh it, and obtain a white solid.

[0035] Example 1 and Comparative Example 1 used the above method to prepare the target product.

[0036] Example 1 Formic acid was used as the reducing agent in the coupling reaction. The molar yield of the product was >85%, and the purity detected by chromatography was >99.5%. The product quality is as follows:

[0037] Traditional Ubbelohde coupling method – high-temperature coupling of halogenated aromatics under copper powder catalysis. Product molar yield 60%, chromatographic purity >98%.

[0038] The liquid crystal material synthesized by thermal polymerization of the modified biphenyl obtained in Example 1 shows the following performance improvement compared to the traditional thermally polymerized biphenyl liquid crystal material:

Claims

1,3,3'-Dihydroisoxazole biphenyl, characterized in that, It has the following structural formula: .

2. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 1, characterized in that, Includes the following steps: 1) 3,3-Dimethacrylate reacts with hydroxyurea, sodium methoxide, and hydrochloric acid to give intermediate BP011-1 with the following structural formula; 2) Intermediate BP011-1 reacts with phosphorus oxychloride and water to obtain intermediate BP011-2 with the following structural formula; 3) Intermediate BP011-2 reacts with o-chloroanisole and magnesium to obtain intermediate BP011-3 with the following structural formula; 4) Intermediate BP011-3 reacts with chlorine to obtain intermediate BP011-4 with the following structural formula; 5) Intermediate BP011-4 reacts with sodium hydroxide to obtain intermediate BP011-5 with the following structural formula; 6) The intermediate BP011-5 reacts with hydrochloric acid to give the target product BP011 with the following structural formula. 。 3. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 2, characterized in that, Step 1) includes the following steps: 11) Sodium methoxide is dissolved in methanol as a substrate, and hydroxyurea is added to the substrate in batches, controlling the reaction temperature to not exceed 50°C; 12) After the reaction in step 11) is complete, add ethyl 3,3-dimethacrylate dropwise to the substrate, and control the reaction temperature to not exceed 40°C; 13) After the reaction in step 12) is complete, the substrate is separated into solid and liquid to obtain a filtrate. The filtrate is distilled under reduced pressure to remove methanol, water is added, and hydrochloric acid is added dropwise, while controlling the reaction temperature to not exceed 75°C. 14) After the reaction in step 13) is complete, extract with dichloromethane to obtain a dichloromethane solution containing intermediate BP011-1.

4. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 3, characterized in that, Step 2) includes the following steps: 21) Triethylamine was added to the dichloromethane solution containing intermediate BP011-1 obtained in step 14) in one step, followed by the addition of phosphorus oxychloride, while controlling the reaction temperature to not exceed 80°C. 22) After the reaction in step 21) is complete, add water dropwise and control the reaction temperature at 30-60℃; 23) After the reaction in step 22) is complete, let it stand to separate into layers, collect the lower aqueous phase, and perform vacuum concentration and distillation to obtain intermediate BP011-2.

5. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 2, characterized in that, Step 3) includes the following steps: 31) Magnesium strips were added to tetrahydrofuran, followed by iodine, as a substrate; 32) The intermediate BP011-2 was dissolved in tetrahydrofuran to obtain a BP011-2 tetrahydrofuran solution; 33) Add BP011-2 tetrahydrofuran solution dropwise to the substrate in step 31), and control the reaction temperature at 10-40℃; 34) After the reaction in step 33) is complete, add o-chloroanisole dropwise, controlling the reaction temperature at 40-60℃; 35) After the reaction in step 34) is complete, add hydrochloric acid dropwise, and control the reaction temperature to not exceed 60℃; 36) After the reaction in step 35) is complete, extract with dichloromethane, collect the lower organic phase, add water and then concentrate and distill under vacuum to obtain intermediate BP011-3.

6. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 2, characterized in that, Step 4) includes the following steps: 41) The intermediate BP011-3 was dissolved in dichloroethane to obtain a BP011-3 dichloroethane solution, and water and ferric chloride were added as substrates; 42) Chlorine gas is introduced into the substrate to carry out the reaction, and the reaction temperature is controlled not to exceed 5°C; 43) After the reaction in step 42) is complete, add sodium sulfite in batches; 44) After the reaction in step 43) is complete, let it stand to separate into layers, collect the lower organic phase, add water, and then perform vacuum concentration and distillation to obtain intermediate BP011-4.

7. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 2, characterized in that, Step 5) includes the following steps: 51) The intermediate BP011-4 was dissolved in dichloroethane to obtain a BP011-4 dichloroethane solution, which was used as a substrate; 52) After adding sodium hydroxide and palladium on carbon catalyst to the substrate, add reducing agent dropwise, and control the reaction temperature to be no lower than 30℃; 53) After the reaction in step 52) is complete, allow it to stand and separate into layers. Collect the lower organic phase to obtain a BP011-5 dichloroethane solution containing intermediate BP011-5.

8. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 7, characterized in that, Step 6) includes the following steps: 61) Add water, hydrochloric acid, and sodium iodide to the BP011-5 dichloroethane solution, and control the reaction temperature to be no lower than 50℃; 62) After the reaction in step 61 is complete, allow it to stand and separate into layers. Collect the lower organic phase, concentrate and crystallize it to obtain the target product BP011.

9. The method for preparing 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 7, characterized in that, In step 52), the reducing agent is formic acid.

10. The application of 3,3'-dihydroisoxazole biphenyl hydroquinone according to claim 1 in liquid crystal materials.

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