3, 3 '-biphenol-thiadiazolyl diurea as well as preparation method and application thereof
By employing an intermolecular coupling method involving aminoacetonitrile hydrochloride, sodium nitrite diazotization, and palladium on carbon catalysis in the synthesis of liquid crystal materials, the problems of numerous side reactions and low purity when introducing functional groups into liquid crystal materials have been solved. This has enabled the preparation of high-purity and high-efficiency liquid crystal materials suitable for harsh environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-03-27
AI Technical Summary
Existing liquid crystal materials suffer from numerous side reactions, low yields, poor product color, and difficulty in purification when different functional groups are introduced, and they cannot be used stably in harsh environments.
A diazotization reaction was carried out using aminoacetonitrile hydrochloride and sodium nitrite in a chloroform-aqueous phase using a microchannel reactor. Subsequently, under alkaline conditions, intermolecular coupling was performed between the reducing agent and palladium on carbon as a catalyst. Finally, the mixture was hydrolyzed with hydrochloric acid under sodium iodide catalysis to synthesize 3,3'-biphenyl-thiadiazolyl diurea.
It achieves high-yield (over 85%) coupling reactions, with high product purity (chromatographic purity ≥ 99.5%), meeting the requirements of special liquid crystal materials, and possessing better conductivity, wear resistance, and cold resistance, making it suitable for harsh environments.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of liquid crystal materials, in particular to 3,3'-biphenyldiol-thiadiazole diurea and a preparation method and application thereof. BACKGROUND
[0002] The most widely used synthetic liquid crystal material (LCP) at present is polymeric biphenyldiol, which is an organic polymer material with electrical conductivity. It is mainly used in the fields of electronics, electrical appliances and semiconductors. With the progress of science and technology, liquid crystal materials with special scene applications and special performance requirements need to introduce different functional groups on biphenyldiol.
[0003] The technical barrier for introducing other functional groups on biphenyldiol is the coupling of aromatic hydrocarbons. The classical aromatic coupling reaction is Ullmann coupling, that is, halogenated aromatic hydrocarbons are coupled under the catalysis of copper powder at a high temperature of 150 DEG C or above. This method has many side reactions, low yield (60%), poor color of product, and purification difficulty.
[0004] In addition, the liquid crystal material prepared from biphenyldiol in the prior art cannot be stably used in harsh weather or environment, and is easily damaged in harsh environment.
[0005] Therefore, 3,3'-biphenyldiol-thiadiazole diurea and a preparation method and application thereof are needed to solve the above technical problems. SUMMARY
[0006] The present application aims to overcome the technical problems existing in the prior art, and provides 3,3'-biphenyldiol-thiadiazole diurea and a preparation method and application thereof.
[0007] 5-aminothiadiazole is synthesized by using aminoacetonitrile hydrochloride and sodium nitrite as raw materials, completing diazotization reaction in a chloroform-water phase under the catalysis of weak acid phosphoric acid, using a micro-channel reactor; 3,3'-biphenyldiol-thiadiazole diurea is synthesized by using noble metal palladium carbon catalyst, adding a reducing agent dropwise under alkaline conditions in a DMF phase, completing intermolecular coupling from thiazole-3-chloroanisole-2-yl urea, and then hydrolyzing with hydrochloric acid under the catalysis of sodium iodide in toluene solvent to synthesize 3,3'-biphenyldiol-thiadiazole diurea.
[0008] To achieve the above purpose, the present application is implemented according to the following technical solutions: 3,3'-biphenyldiol-thiadiazole diurea has the following structural formula: .
[0009] The present application also includes a preparation method of 3,3'-biphenyldiol-thiadiazole diurea, comprising the following steps: S1, aminoacetonitrile hydrochloride reacts with sodium nitrite via a diazotization reaction to form aminoacetonitrile diazonium salt; aminoacetonitrile diazonium salt is denoted as BP010-1; the reaction equation is as follows: .
[0010] S2, the diazonium salt of aminoacetonitrile undergoes a cyclization reaction with hydrogen sulfide to generate 5-aminothiadiazole; 5-aminothiadiazole is designated as BP010-2; the reaction equation is as follows: .
[0011] S3,5-aminothiadiazole reacts with 3-chloro-6-methoxyphenyl isocyanate to generate the intermediate thiadiazole-3-chloroanisole-2-ylurea with the following structural formula, denoted as BP010-3. ; This reaction is an amidation reaction, and the reaction equation is as follows: .
[0012] S4, intermediate BP010-3 reacts with sodium hydroxide to generate intermediate 3,3'-phthaloyl-thiadiazole diurea with the following structural formula, denoted as BP010-4: ; This reaction is a coupling reaction, and the reaction equation is as follows: .
[0013] S5, intermediate BP010-4 reacts with hydrochloric acid to generate the target product 3,3'-biphenyl-thiadiazolyl diurea, denoted as BP010, with the following structural formula: ; This reaction is a hydrolysis reaction, and the reaction equation is as follows: .
[0014] Preferably, step S3 includes the following steps: S3.1, Add ethylene glycol dimethyl ether and 5-aminothiadiazole to the reaction vessel; S3.2 When the temperature of the reaction vessel reaches 40-50℃, add phenyl 3-chloro-6-methoxyisocyanate to carry out the reaction. The temperature during the reaction shall not exceed 70℃. S3.3 After the reaction is complete, the temperature is lowered, the reaction product is filtered and dried to obtain the intermediate thiadiazolyl-3-chloroanisole-2-ylurea, denoted as BP010-3.
[0015] Preferably, step S4 includes the following steps: S4.1, add DMF, palladium on carbon (Pd / C), BP010-3, water, and sodium hydroxide to the reaction vessel; S4.2 When the temperature of the reaction vessel reaches above 80℃, add the reducing agent to carry out the reaction, and control the temperature of the reaction process at 80-95℃; S4.3 After the reaction is complete, the temperature is lowered, and the reaction product is filtered and washed to obtain intermediate BP010-4.
[0016] Preferably, in step S4.2, the reducing agent is formic acid.
[0017] Preferably, step S5 includes the following steps: S5.1, add toluene, intermediate BP010-4, sodium iodide, water, and hydrochloric acid to the reaction vessel; S5.2, When the temperature of the reaction vessel reaches 60-85℃, start timing to carry out the reaction; S5.3 After the reaction is complete, the temperature is lowered. When the temperature inside the reaction vessel is below 40°C, the reaction solution is separated. The organic phase obtained by separation is washed with water, concentrated, and crystallized to obtain the target product 3,3'-biphenyldiphenol-thiadiazole diurea.
[0018] Preferably, step S1 includes the following steps: Starting with aminoacetonitrile hydrochloride, it reacts with sodium nitrite at low temperature via diazotization to generate aminoacetonitrile diazonium salt.
[0019] Preferably, step S1 includes the following steps: S1.1, A mixed solution is obtained by mixing an aqueous solution of aminoacetonitrile hydrochloride with an aqueous solution of phosphoric acid; S1.2, the mixed solution, sodium nitrite aqueous solution, and chloroform are respectively added to a microchannel reactor for reaction at a reaction temperature of -10 to 10℃; S1.3 After the reaction is completed, the reaction solution is allowed to stand and separate into layers. The lower layer is then extracted to obtain an oil phase containing diazonium aminoacetonitrile salt.
[0020] Preferably, step S2 includes the following steps: S2.1, Triethylamine is added to the oil phase containing diazonium aminoacetonitrile, followed by the introduction of hydrogen sulfide to carry out the reaction; the reaction temperature is -10 to 10℃ during the reaction process; S2.2 After the reaction is complete, filter and dry to obtain 5-aminothiadiazole.
[0021] The 5-aminothiadiazole prepared by this invention has a lower cost.
[0022] The present invention also includes the application of 3,3'-biphenyl-thiadiazole diurea in liquid crystal materials.
[0023] The 3,3'-biphenyl-thiadiazole-diurea prepared by this invention meets the relevant quality indicators in Table 1.
[0024]
[0025] The liquid crystal material synthesized by thermal polymerization of the modified biphenyl 3,3'-biphenyl-thiadiazole diurea of the present invention shows improved performance compared with the traditional thermally polymerized biphenyl liquid crystal material, as shown in Table 2 below.
[0026]
[0027] This invention discovers that, under alkaline conditions, using palladium on carbon as a catalyst and adding formic acid as a reducing agent, the coupling of haloaromatics can be achieved in high yield (over 85%) under mild conditions. The process is low-cost, yields high-purity products (chromatographic purity ≥ 99.5%), and meets the requirements of special liquid crystal materials.
[0028] Beneficial effects: (1) The novel liquid crystal material 3,3'-biphenyl-thiadiazole diurea produced by the present invention introduces different functional groups on biphenyl to achieve different application scenarios. Compared with traditional materials, the material prepared by the present invention has better conductivity, wear resistance, moisture resistance, cold resistance, etc., breaking the technical barriers to the application of liquid crystal materials in the market (such as the inability to use stably in harsh climates or places).
[0029] (2) In the preparation method of the present invention, the yield and quality of the product are better than those of traditional processes and materials.
[0030] (3) The production process of this invention adopts full automation, 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
[0031] The present invention will be further described below with reference to specific embodiments. The illustrative embodiments and descriptions herein are used to explain the present invention, but are not intended to limit the present invention.
[0032] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.
[0033] There are no particular restrictions on the purity of any of the raw materials used in this invention, but it is preferred to use materials with conventional purity levels used in the field.
[0034] All processes in this invention are referred to by abbreviations that are common abbreviations in the field. Each abbreviation is clear and specific in its relevant application area, and those skilled in the art can understand its conventional process steps based on the abbreviation.
[0035] Example 1 The preparation method of 3,3'-biphenyl-dihydroxy-thiadiazole diurea includes the following steps: I. Diazotization-cyclization reaction (the first two steps must be carried out consecutively) ①Preparation of aminoacetonitrile hydrochloride aqueous solution: 1) Place a 500ml beaker on a reducing balance, add 150g of water and 100g of aminoacetonitrile hydrochloride; 2) Stir until clear (referred to as solution 1); ② Preparation of sodium nitrite aqueous solution: 1) Place a 500ml beaker on a reducing balance, add 180g of water and 90g of sodium nitrite; 2) Stir until clear (referred to as solution 2); ③ Preparation of phosphoric acid aqueous solution: 1) Place a 200ml beaker on a reducing balance, add 27.5g of water and 17.5g of 85% phosphoric acid; 2) Stir until clear (referred to as solution 3); ④ Diazotization-cyclization reaction: 1) Pre-cooling: Mix solution 1 (aminoacetonitrile hydrochloride aqueous solution) and solution 3 (phosphoric acid aqueous solution) thoroughly and transfer to pre-cooling bottle 1. Transfer solution 2 (sodium nitrite aqueous solution) to pre-cooling bottle 2. Transfer 700g of chloroform as a solvent to pre-cooling bottle 3. Pre-cool all solutions to 0±10℃ for later use. 2) Connect the constant flow pump tubing connecting precooling bottles 1, 2, and 3 to the microchannel reactor. Set the flow rates to 8 ml / min, 7 ml / min, and 15 ml / min, respectively. 3) Set the chiller temperature to -35℃ and open the inlet and outlet valves for the cooling water in the microchannel reactor; 4) When the microchannel reactor temperature reaches -10℃, start each constant flow pump to carry out the diazotization reaction. During the process, control the reaction temperature at 0±10℃. The diazo reaction solution overflows into a 2000ml glass reactor (circulating -35℃ cooling water). 5) After one batch of diazotization reaction is complete, stop stirring and allow to stand for phase separation. Transfer the lower layer to a 1000ml three-necked flask; 6) After stirring for 5 minutes, add 650 ml of pre-cooled chloroform to the flask, stir and extract for 5 minutes, let stand for 5 minutes to separate the layers, and collect the lower oil phase into the flask. 7) Continue the above steps and add 650ml of chloroform again for extraction and separation. Collect the upper aqueous phase into the waste liquid tank for centralized disposal. 8) Add 20 ml of triethylamine dropwise to the flask; when the temperature reaches 0 ± 10℃, slowly open the valve of the hydrogen sulfide cylinder to begin releasing hydrogen sulfide. During the process, control the temperature in the flask to 0 ± 10℃; 9) After the reaction is complete, filter through a Buchner funnel. Wash the filter cake with a small amount of chloroform and dry it. Recover the chloroform from the filtrate by distillation. 10) The filter cake is dried in a forced-air drying oven at 35-60℃. If the moisture content is ≤0.5%, it is considered qualified. Weigh it to obtain a pale yellow 5-aminothiadiazole.
[0036] II. Amide reaction 1) Add 330g of ethylene glycol dimethyl ether to a 1000ml three-necked flask equipped with a 0-100℃ mercury thermometer, a 250ml constant pressure funnel, and a mechanical stirrer, and add 55g of the 5-aminothiadiazole synthesized in the previous step. 2) Start stirring and add phenyl 3-chloro-6-methoxyisocyanate to the constant pressure funnel; 3) Set the water bath temperature to 80℃; 4) When the temperature in the three-necked flask reaches 40-50℃, begin adding phenyl 3-chloro-6-methoxyisocyanate dropwise. During the process, the temperature inside the flask should not exceed 70℃. 5) After adding 3-chloro-6-methoxyphenyl isocyanate, continue the reaction at this temperature for 2 hours, then take a sample for testing. The reaction is considered complete when HPLC (High Performance Liquid Chromatography) shows that the residual 5-aminothiadiazole in the starting material is ≤0.5%. Otherwise, continue the reaction until the endpoint is reached. 6) Cool down to below 20°C inside the flask, filter using a Buchner funnel to obtain a filter cake; 7) The filter cake was placed in an 80℃ oven and vacuum dried to obtain a white solid BP010-3. The filtrate was collected and the solvent was recovered.
[0037] III. Coupling Reaction 1) Add 280g of DMF to a 2000ml three-necked flask equipped with a 0-150℃ mercury thermometer, mechanical stirrer, 50ml constant pressure funnel, reflux condenser, and oil bath; 2) Start stirring, add 5g of palladium on carbon, 150g of the product from the previous step (BP010-3), and 300g of water. Slowly add 25.5g of caustic soda flakes; 3) Set the oil bath temperature to 120℃ and add 25.5g of reducing agent to the constant pressure funnel; 4) When the temperature inside the three-necked flask reaches above 80°C, begin adding the reducing agent dropwise. During the process, the temperature inside the three-necked flask should be controlled between 80-95°C. 5) After adding the reducing agent, continue the reaction at this temperature for 2 hours, then take a sample for testing. HPLC results should show that the residue of raw material BP010-3 is ≤0.5%, indicating the reaction is complete. Otherwise, continue the reaction until the endpoint is reached. 6) Cool down to room temperature, filter, and wash the filter cake with 30g of water; 7) Transfer the filtrate to a 2000ml three-necked flask, add 300g of water, and stir for 1 hour; 8) Filter, collect the filter cake, weigh the wet product to obtain the reaction product BP010-4 wet product; after passing HPLC testing, BP010-4 wet product is used in the next process. 9) The product yield was measured and calculated to be >85%, which is 25% higher than that of the traditional coupling method (average 60%).
[0038] IV. Hydrolysis reaction 1) Add 300g of toluene to a 2000ml three-necked flask equipped with a mechanical stirrer, thermometer, condenser and oil bath, and add 150g of the wet product BP010-4 from the previous step. 2) Start stirring and continue adding 1.8g of sodium iodide, 50g of water, and 38.5g of hydrochloric acid; 3) Set the oil bath temperature to 120℃ and begin the reaction; start timing when the temperature inside the flask reaches 60-85℃. Maintain the reaction temperature for 12 hours, then take a sample for testing. The reaction is considered complete when HPLC shows that the residue of the raw material BP010-4 is less than 0.2%. Otherwise, continue reflux to the endpoint. 4) Change the oil bath to a cooling bath. When the temperature inside the flask is below 40℃, transfer the reaction solution into a 2000ml separatory funnel. Separate the lower aqueous phase, and wash the upper organic phase with water until neutral. Transfer the upper organic phase into a 1000ml flask equipped with vacuum distillation. 5) Set the water bath temperature to 85℃, turn on the benchtop water-flushing vacuum pump, and ensure the vacuum pressure is not less than -0.09MPa to concentrate toluene; 6) When the temperature inside the bottle reaches 75℃, turn off the vacuum pump and switch the water bath to cooling. When the temperature inside the bottle reaches 40℃, add 200g of methanol and continue stirring to cool. When the temperature inside the bottle drops below 30℃, continue stirring to allow crystallization to occur for 5 hours. 7) Filter by vacuum drying. The filter cake is dried under vacuum. The oven temperature is set to 75℃. If the moisture content is ≤0.5%, it is considered qualified. 8) Weighing, we get white solid BP010.
[0039] In this embodiment, the reducing agent used in the coupling reaction is formic acid.
[0040] The 3,3'-biphenyldiphenol-thiadiazole diurea prepared in Example 1 was tested, and its quality indicators met the requirements in Table 1.
[0041] The liquid crystal material synthesized by thermal polymerization of 3,3'-biphenyl-dihydroxydiurea prepared in Example 1 was tested, and the data in Table 3 were obtained.
[0042]
[0043] Comparative Example 1 The traditional Ubbelohde coupling method—high-temperature coupling of halogenated aromatic hydrocarbons catalyzed by copper powder—was used. The product molar yield was 60%, and the chromatographic purity was >98%.
[0044] The coupling reaction in Example 1 of the present invention uses palladium on carbon as a catalyst and formic acid as a reducing agent, with a product molar yield >85% and chromatographic purity >99.5%.
[0045] Therefore, it can be concluded that, compared with the traditional process, the product molar yield and chromatographic purity of the present invention are superior to those of the traditional process.
[0046] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.
Claims
1. 3,3'-Bisphenol-thiadiazolyl diurea, characterized in that, It has the following structural formula: 。 2. The method for preparing 3,3'-biphenyl-dihydroxy-thiadiazolyl diurea according to claim 1, characterized in that, Includes the following steps: S1, aminoacetonitrile hydrochloride reacts with sodium nitrite via a diazotization reaction to form aminoacetonitrile diazonium salt, the structural formula of which is as follows: ； S2, the diazonium salt of aminoacetonitrile undergoes a cyclization reaction with hydrogen sulfide to generate 5-aminothiadiazole, the structural formula of which is as follows: ； S3,5-aminothiadiazole reacts with 3-chloro-6-methoxyphenyl isocyanate to generate the intermediate thiadiazole-3-chloroanisole-2-ylurea with the following structural formula, denoted as BP010-3. ； S4, intermediate BP010-3 reacts with sodium hydroxide to generate intermediate 3,3'-phthaloyl-thiadiazole diurea with the following structural formula, denoted as BP010-4: ； S5, intermediate BP010-4 reacts with hydrochloric acid to generate the target product 3,3'-biphenyl-thiadiazolyl diurea with the following structural formula: 。 3. The method for preparing 3,3'-biphenyl-thiadiazole-diurea according to claim 2, characterized in that, Step S3 includes the following steps: S3.1, Add ethylene glycol dimethyl ether and 5-aminothiadiazole to the reaction vessel; S3.2 When the temperature of the reaction vessel reaches 40-50℃, add phenyl 3-chloro-6-methoxyisocyanate to carry out the reaction. The temperature during the reaction shall not exceed 70℃. S3.3 After the reaction is complete, the temperature is lowered, the reaction product is filtered and dried to obtain the intermediate thiadiazolyl-3-chloroanisole-2-ylurea, denoted as BP010-3.
4. The method for preparing 3,3'-biphenyl-dioxopropyl-thiadiazole diurea according to claim 2, characterized in that, Step S4 includes the following steps: S4.1, add DMF, palladium on carbon, BP010-3, water, and sodium hydroxide to the reaction vessel; S4.2 When the temperature of the reaction vessel reaches above 80℃, add the reducing agent to carry out the reaction, and control the temperature of the reaction process at 80-95℃; S4.3 After the reaction is complete, the temperature is lowered, and the reaction product is filtered and washed to obtain intermediate BP010-4.
5. The method for preparing 3,3'-biphenyl-dioxopropyl-thiadiazole diurea according to claim 2, characterized in that, In step S4.2, the reducing agent is formic acid.
6. The method for preparing 3,3'-biphenyl-dihydroxy-thiadiazole diurea according to claim 2, characterized in that, Step S5 includes the following steps: S5.1, add toluene, intermediate BP010-4, sodium iodide, water, and hydrochloric acid to the reaction vessel; S5.2, When the temperature of the reaction vessel reaches 60-85℃, start timing to carry out the reaction; S5.3 After the reaction is complete, the temperature is lowered. When the temperature inside the reaction vessel is below 40°C, the reaction solution is separated. The organic phase obtained by separation is washed with water, concentrated, and crystallized to obtain the target product 3,3'-biphenyldiphenol-thiadiazole diurea.
7. The method for preparing 3,3'-biphenyl-diazolyl-thiadiazole diurea according to claim 2, characterized in that, Step S1 includes the following steps: S1.1, A mixed solution is obtained by mixing an aqueous solution of aminoacetonitrile hydrochloride with an aqueous solution of phosphoric acid; S1.2, the mixed solution, sodium nitrite aqueous solution, and chloroform are respectively added to a microchannel reactor for reaction at a reaction temperature of -10 to 10℃; S1.3 After the reaction is completed, the reaction solution is allowed to stand and separate into layers. The lower layer is then extracted to obtain an oil phase containing diazonium aminoacetonitrile salt.
8. The method for preparing 3,3'-biphenyl-diazolyl-thiadiazole diurea according to claim 2, characterized in that, Step S2 includes the following steps: S2.1, Triethylamine is added to the oil phase containing diazonium aminoacetonitrile, followed by the introduction of hydrogen sulfide to carry out the reaction; the reaction temperature is -10 to 10℃ during the reaction process; S2.2 After the reaction is complete, filter and dry to obtain 5-aminothiadiazole.
9. The application of 3,3'-biphenyl-thiadiazole diurea according to claim 1 in liquid crystal materials.