A high temperature tetraloop liquid crystal compound and a preparation method and application thereof

Abstract

This invention relates to a high-temperature tetracyclic liquid crystal compound, its preparation method, and its applications, belonging to the fields of chemical synthesis and liquid crystal materials technology. The high-temperature tetracyclic liquid crystal compound has the structure shown in general formula I: wherein R1 represents H, a C1-C12 alkyl group, or a C2-C12 alkylenyl group, and one or more CH2 groups can be independently replaced by -CF=CH-, -CF=CF-, -CH=CF-, -COO-, or -O-; X represents CF3 or OCF3. This invention also discloses the synthesis method and applications of this compound. This compound exhibits higher resolution and a wider liquid crystal phase transition temperature range, and can be used to prepare liquid crystal mixtures with high operating temperatures. It is suitable as a high-temperature component of TFT mixed liquid crystals and has excellent application prospects in thin-film transistor liquid crystal displays.

Description

Technical Field

[0001] This invention relates to a high-temperature tetracyclic liquid crystal compound, its preparation method, and its application, mainly used in TFT liquid crystal displays, and belongs to the fields of chemical synthesis and liquid crystal materials technology. Background Technology

[0002] Liquid crystal materials, as environmentally friendly materials, have significant research value and promising application prospects in fields such as information display materials and organic optoelectronic materials. As a novel display material, liquid crystal materials offer numerous advantages, such as extremely low power consumption and low driving voltage. Compared to other materials, they also possess advantages such as small size, light weight, long lifespan, large display information capacity, and no electromagnetic radiation, making them suitable for almost all information display requirements, especially in TFT-LCD (Thin Film Transistor) products.

[0003] In TFT active matrix systems, the main display modes include TN (Twisted Nematic) mode, IPS (In-Plane Switching) mode, FFS (Fringe Field Switching) mode, and VA (Vertical Alignment) mode.

[0004] Currently, TFT-LCD technology is mature, successfully solving technical challenges such as viewing angle, resolution, color saturation, and brightness. Large-size and small-to-medium-size TFT-LCD displays have gradually become the mainstream flat panel displays in their respective fields. However, the requirements for display technology continue to increase, demanding faster response times and lower driving voltages to reduce power consumption in LCD displays.

[0005] Liquid crystal materials themselves play a crucial role in improving the performance of liquid crystal displays, especially in reducing their rotational viscosity and increasing their dielectric anisotropy Δε. To improve material properties and adapt them to new requirements, the synthesis of novel liquid crystal compounds and the study of their structure-property relationships have become important work in the field of liquid crystals.

[0006] Liquid crystal display elements (LCDs) using liquid crystal compositions are widely used in displays for watches, calculators, word processors, and more. These LCDs utilize the refractive index anisotropy and dielectric anisotropy of liquid crystal compounds.

[0007] These liquid crystal display elements comprise liquid crystal compositions with appropriate physical properties. In recent years, there has been a particular demand for liquid crystal display elements with higher display performance, such as contrast ratio, display capacity, and response time characteristics. This, in turn, necessitates liquid crystal compositions with low rotational viscosity and low driving voltage. Summary of the Invention

[0008] For commercial displays such as outdoor displays, a wider display temperature range is required, which means that the liquid crystal has high-definition bright spots and a low operating temperature. However, mixtures with high-definition bright spots usually have high viscosity, which leads to a delay in response time. Therefore, it is necessary to develop liquid crystal compositions with a wider operating range, as well as lower viscosity and faster response time.

[0009] One of the objectives of this invention is to provide a tetracyclic liquid crystal compound with high-definition brightness and wide temperature range.

[0010] Another object of the present invention is to provide a method for synthesizing the above-mentioned compounds, which can reduce production costs.

[0011] Another object of the present invention is to provide an application of the above-mentioned compound, which has the characteristics of high-definition brightness, wide nematic phase temperature range and high polarity, and is used as a high-temperature component of TFT mixed liquid crystal in the liquid crystal of a high-stability TFT mode display for TV LCD televisions.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A high-temperature tetracyclic liquid crystal compound, the structure of which is shown in general formula I:

[0014]

[0015] Wherein, R1 represents H, a C1-C12 alkyl group, or a C2-C12 alkylene group, and one or more CH2 groups therein can be independently... -CF=CF-, -CF=CF-, -CH=CF-, -COO- or -O- substitution; X represents CF3 or OCF3.

[0016] Preferably, R1 represents an alkyl group having 1 to 9 carbon atoms, a fluorinated alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorinated alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorinated alkenyl group having 2 to 9 carbon atoms, an alkenyl group having 3 to 8 carbon atoms, or a fluorinated alkenyl group having 3 to 8 carbon atoms; X represents CF3 or OCF3.

[0017] The liquid crystal compound of general formula I is further preferably one or more of the following structural compounds:

[0018]

[0019]

[0020] The synthesis reaction of the compound of general formula I in this invention is as follows:

[0021]

[0022] Where n represents 1 to 12.

[0023] A method for preparing a high-temperature tetracyclic liquid crystal compound having the above structure includes the following steps:

[0024] 1) Preparation of CCGPCF3-1

[0025] Dicyclohexyl ketone and tetrahydrofuran were dissolved by stirring at room temperature. Magnesium m-fluorophenyl bromide was added dropwise while maintaining the temperature below 30°C. After the addition was complete, the temperature was maintained at 30-35°C for 3 hours. The resulting gray solution was observed on a TLC plate after the initial reaction was complete. The system was cooled to room temperature, and the reaction solution was slowly poured into an ice-water solution of hydrochloric acid to quench the reaction. After quenching, ethyl acetate was added for extraction twice. The combined organic phases were washed once each with saturated sodium bicarbonate and water. The mixture was separated, and the organic phase was dried over anhydrous magnesium sulfate. After filtration, the organic phase was concentrated and dried under reduced pressure to obtain an oily substance.

[0026] 2) Preparation of CCGPCF3-2

[0027] Toluene and p-toluenesulfonic acid monohydrate were added to CCGPCF3-1, stirred and heated to reflux to separate water, and a sample was taken for testing. The reaction of the raw materials was complete. The system was cooled to room temperature, and saturated sodium bicarbonate and water were slowly poured in to wash once each. The organic phase was concentrated and dried under reduced pressure to obtain an oily substance.

[0028] 3) Preparation of CCGPCF3-3

[0029] Toluene and Pd carbon were added to CCGPCF3-2, pressurized with a hydrogen balloon, stirred and heated to 30-35℃, and reacted overnight. Samples were taken and sent for testing after the raw materials had reacted completely. The system was cooled to room temperature, and filtered through a funnel lined with diatomaceous earth. The filtrate was concentrated and dried under reduced pressure to obtain an oily substance.

[0030] 4) Preparation of CCGPCF3-4

[0031] Dichloromethane was added to CCGPCF3-3 and stirred until dissolved at room temperature. The temperature was lowered to -5 to 0°C, and aluminum trichloride was added in batches. After the addition was complete, the reaction was kept at -5 to 0°C and a sample was sent for testing. The reaction solution was slowly poured into ice water to quench it, stirred until dissolved at room temperature, and separated. The organic phase was washed once with saturated sodium bicarbonate and once with water. The organic phase was concentrated and dried under reduced pressure to obtain an oily substance.

[0032] 5) Preparation of CCGPCF3-5

[0033] 2.2.6.6-Tetramethylpiperidine and tetrahydrofuran were stirred and cooled to -40°C. Butyllithium was added dropwise, and the mixture was kept at this temperature after the addition was complete. The mixture was then cooled to -70°C to -80°C, and triisopropyl borate was added dropwise. After the addition was complete, the mixture was kept at this temperature. The mixture was then cooled to -70°C to -80°C, and a tetrahydrofuran solution of CCGPCF3-4 was added dropwise. After the addition was complete, the mixture was kept at -40°C to -50°C, and then at -2°C to -30°C. The mixture was then spotted onto a TLC plate, and the reaction was complete. Water was slowly added to quench the reaction, and the mixture was stirred at room temperature. The pH was adjusted to 2-3 with hydrochloric acid. The mixture was separated into liquid and liquid phases. The aqueous phase was extracted twice with ethyl acetate, and the organic phase was concentrated and dried under reduced pressure to obtain a yellow solid. Heptane was added, and the mixture was stirred and heated to reflux to form a slurry. The mixture was cooled to room temperature to crystallize, filtered, and dried.

[0034] 6) Preparation of CCGPCF3-6

[0035] Add 4-bromotrifluorotoluene, potassium carbonate, ethanol, and catalyst to CCGPCF3-5, purge with nitrogen, stir, and heat to reflux; maintain the temperature for reaction; after the reactants have reacted completely, slowly pour the reaction solution into water to quench it, add n-heptane for extraction, separate the liquids, wash the organic phase once with water, concentrate and dry the organic phase under reduced pressure to obtain a yellow solid; pass n-heptane through a column to obtain a white solid; add n-heptane, stir, and heat to clear the solution, cool to 0-5℃ to crystallize, filter, and obtain a white solid, which is the target product.

[0036] Furthermore, the preparation method of the high-temperature tetracyclic liquid crystal compound having the above structure includes the following specific steps:

[0037] 1) Preparation of CCGPCF3-1

[0038] Add 50g of dicyclohexyl ketone and 100mL of tetrahydrofuran to a 500mL three-necked flask and stir until dissolved at room temperature (10-20℃). Control the temperature below 30℃ and add 1M magnesium m-fluorophenyl bromide (250mL) dropwise. After the addition is complete below 30℃, control the temperature at 30-35℃ and maintain the reaction for 3 hours. The system becomes a gray solution; the reaction proceeds as indicated by TLC. Cool the system to room temperature and slowly pour the reaction solution into 100g of 3N hydrochloric acid in ice water to quench the reaction. After quenching, extract twice with 100mL of ethyl acetate. Combine the organic phases and wash once each with 50mL of saturated sodium bicarbonate and 50mL of water. Separate the liquids and dry the organic phase with anhydrous magnesium sulfate. Filter and concentrate the organic phase under reduced pressure (solvent removal temperature ≤50℃) to obtain 58g of oil, which can be used directly in the next reaction without purification.

[0039] 2) Preparation of CCGPCF3-2

[0040] Add CCGPCF3-1 (58g), toluene (290mL), and p-toluenesulfonic acid monohydrate (3.0g) to a 500mL three-necked flask. Stir and heat to reflux for 13 hours to separate water. Take a sample for testing. The reaction of the raw materials is complete. Cool the system to room temperature and slowly pour in 50mL of saturated sodium bicarbonate and 50mL of water to wash once each. Concentrate and dry the organic phase under reduced pressure (concentration temperature ≤50℃): 56g of oily substance; purity 85%, directly used for the next reaction.

[0041] 3) Preparation of CCGPCF3-3

[0042] Add 56g of CCGPCF3-2, 280mL of toluene, and 2.8g of Pd carbon (5% w / w) to a 500mL three-necked flask. Pressurize with a hydrogen balloon, stir, and heat to 30-35℃. Maintain the temperature overnight. After reacting for 20 hours, take a sample for testing. Once the reaction is complete, cool the system to room temperature and filter through a funnel lined with diatomaceous earth. Concentrate and dry the filtrate under reduced pressure (T≤50℃): 56g of oily substance. This can be used directly in the next step.

[0043] 4) Preparation of CCGPCF3-4

[0044] Add 56g of CCGPCF3-3 and 560mL of dichloromethane to a 500mL three-necked flask and stir at room temperature until dissolved. Cool to -5 to 0℃ and add 37g of aluminum trichloride in portions over 10 minutes. After adding the aluminum trichloride, maintain the temperature at -5 to 0℃ for 1.5 hours and take a sample for testing. Slowly pour the reaction solution into 560mL of ice water to quench the reaction, stir at room temperature until dissolved, separate the liquids, wash the organic phase once with saturated sodium bicarbonate, wash the organic phase once with water, and concentrate and dry the organic phase under reduced pressure (concentration temperature ≤40℃): 54g of oily substance.

[0045] 5) Preparation of CCGPCF3-5

[0046] Add 37.8 g of 2,2,6,6-tetramethylpiperidine and 280 mL of tetrahydrofuran to a 1000 mL three-necked flask, stir and cool to -40 °C, then add 108 mL of 2.5 M butyllithium dropwise over half an hour, and keep warm for 1 hour; cool to -70 °C to -80 °C, then add 67 g of triisopropyl borate dropwise over half an hour, and keep warm for 1 hour; cool to -70 °C to -80 °C, then add 50 mL of a 56 g solution of 3 CCGPCF3-4. After adding the solution dropwise over half an hour, maintain the temperature at -40 to -50°C for 1 hour; then maintain the temperature at -2 to -30°C for 1 hour; perform TLC to indicate that the starting material has reacted completely; slowly add 200 ml of water to quench the reaction, stir at room temperature, add 3N hydrochloric acid to adjust the pH to 2-3, separate the liquid and extract the aqueous phase twice with 112 ml of ethyl acetate, concentrate the organic phase under reduced pressure to dryness (concentration temperature ≤50°C): 40 g of yellow solid; add 112 ml of n-heptane, stir and heat to reflux for 1 hour, cool to room temperature for 2 hours to crystallize, filter, and dry at 50°C to obtain 17.3 g;

[0047] 6) Preparation of CCGPCF3-6

[0048] In a 250 mL three-necked flask, add CCGPCF3-5 (17 g), 4-bromotrifluorotoluene (12.2 g), potassium carbonate (10.2 g), ethanol (170 mL), and catalyst (Pd catalyst, 0.34%, w / w). Purge with nitrogen three times, stir, and heat to reflux. Maintain the reaction temperature for 20 h. After the reactants have reacted, slowly pour the reaction solution into 250 mL of water to quench. Add 100 mL of n-heptane and extract twice. Separate the solutions, wash the organic phase once with water, and concentrate and dry the organic phase under reduced pressure (concentration temperature ≤50℃): 18 g of yellow solid. Pass n-heptane through a column to obtain 15 g of white solid. Add 14 mL of n-heptane, stir, and heat to 60℃ to dissolve the solid. Cool to 0-5℃ to crystallize for 2 h, filter, and obtain 6.5 g of white solid, which is the target product. Purity: 99.96%.

[0049] Compared with the conventional CCGPCF3 synthesis method (CN102633595B), the synthesis method of the present invention has fewer steps (reducing iodination reactions, etc.), thus lower cost and more suitable for industrial application. At the same time, it obtains high-definition bright spots and high-polarity liquid crystals, which can be used to prepare liquid crystal mixtures with high operating temperatures.

[0050] An application of a high-temperature tetracyclic liquid crystal compound, particularly in liquid crystal compositions, is disclosed, wherein the tetracyclic liquid crystal compound serves as a high-temperature component in TFT hybrid liquid crystals. This liquid crystal compound is suitable as a high-temperature component in TFT hybrid liquid crystals and shows promising application prospects in thin-film transistor (TFT) liquid crystal displays. Liquid crystal compositions containing the aforementioned high-temperature tetracyclic liquid crystal compound can be applied to TFT liquid crystal displays.

[0051] The present invention also provides a liquid crystal composition comprising an improved component liquid crystal compound I, the liquid crystal composition comprising one or more compounds represented by general formula I, and further comprising one or more compounds represented by general formula II and one or more compounds represented by general formula III.

[0052] In the liquid crystal composition, the mass percentage content of the compound represented by general formula I is 0.1%-10%, preferably 0.5%-8%, more preferably 0.5%-5%; the mass percentage content of the compound represented by general formula II is 5%-85%, preferably 5%-80%, 30%-80%, 40%-80%, 50%-80%, 10%-60%, 10%-50%; and the mass percentage content of the compound represented by general formula III is 5%-85%, preferably 5%-50%, 5%-40%, more preferably 10%-35%.

[0053] A liquid crystal composition comprising one or more compounds represented by general formula I:

[0054]

[0055] Wherein, R1 represents H, a C1-C12 alkyl group, or a C2-C12 alkylene group, and one or more CH2 groups therein can be independently... -CF=CH-, -CF=CF-, -CH=CF-, -COO- or -O- substitution; X represents CF3 or OCF3;

[0056] One or more compounds of general formula II are used as component II:

[0057]

[0058] R2 and R3 are independently represented as alkyl with 1 to 9 carbon atoms, fluorinated alkyl with 1 to 9 carbon atoms, alkoxy with 1 to 9 carbon atoms, fluorinated alkoxy with 1 to 9 carbon atoms, alkenyl with 2 to 9 carbon atoms, fluorinated alkenyl with 2 to 9 carbon atoms, alkenyl with 3 to 8 carbon atoms, or fluorinated alkenyl with 3 to 8 carbon atoms.

[0059] A1, A2, and A3 can be represented independently as follows:

[0060] m represents 0 or 1;

[0061] And one or more compounds represented by general formula III as the third component:

[0062]

[0063] R4 and R6 are independently represented as alkyl with 1 to 9 carbon atoms, fluorinated alkyl with 1 to 9 carbon atoms, alkoxy with 1 to 9 carbon atoms, fluorinated alkoxy with 1 to 9 carbon atoms, alkenyl with 2 to 9 carbon atoms, fluorinated alkenyl with 2 to 9 carbon atoms, alkenyl with 3 to 8 carbon atoms, or fluorinated alkenyl with 3 to 8 carbon atoms.

[0064] R5 is represented as -CF2O-, a single bond, or -CH2O-;

[0065] B1 is represented as

[0066] B2, B3, and B4 are each represented independently as follows:

[0067] n represents 0 or 1.

[0068] Furthermore, the liquid crystal compound represented by general formula II is preferably one or more of the following structural compounds:

[0069]

[0070] R2 and R3 are independently represented as alkyl with 1 to 9 carbon atoms, fluorinated alkyl with 1 to 9 carbon atoms, alkoxy with 1 to 9 carbon atoms, fluorinated alkoxy with 1 to 9 carbon atoms, alkenyl with 2 to 9 carbon atoms, fluorinated alkenyl with 2 to 9 carbon atoms, alkenyl with 3 to 8 carbon atoms, or fluorinated alkenyl with 3 to 8 carbon atoms.

[0071] Furthermore, the liquid crystal compound represented by general formula III is preferably one or more of the following structural compounds:

[0072]

[0073] In addition to the compounds mentioned above, the liquid crystal compositions of the present invention may also contain conventional nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, antioxidants, ultraviolet absorbers, infrared absorbers, polymerizable monomers and / or light stabilizers, etc.

[0074] The following shows possible dopants that are preferably added to the liquid crystal composition of the present invention:

[0075]

[0076]

[0077]

[0078] Where n represents 1 to 18.

[0079] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined with each other to obtain various preferred embodiments of the present invention.

[0080] Advantages of this invention:

[0081] Compared with existing technologies, the tetracyclic liquid crystal compound provided by this invention has the advantages of fewer synthesis steps and lower synthesis cost. At the same time, the compound has a high clarity point, a large refractive index, and good light stability and thermal stability, making it suitable for IPS and FFS type liquid crystal displays and effectively improving liquid crystal displays.

[0082] The synthesis method of this invention is suitable for industrial application. Compared with the previous synthesis method (CN102633595B), the synthesis method of this invention has fewer steps, lower cost, and is more scalable. Simultaneously, this compound exhibits higher resolution and a wider liquid crystal phase transition temperature range, enabling it to be used to prepare liquid crystal mixtures with high operating temperatures. It is suitable as a high-temperature component of TFT mixed liquid crystals and has excellent application prospects in thin-film transistor liquid crystal displays. Detailed Implementation

[0083] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments. Any simple substitutions or improvements made to the invention by those skilled in the art are within the scope of the technical solutions protected by the present invention.

[0084] Example 1: Synthesis of compound A (3CCGPCF3)

[0085]

[0086] The basic synthesis reaction of compound A is shown in the following equation:

[0087]

[0088] The specific synthesis steps described above are as follows:

[0089] 1) Preparation of 3CCGPCF3-1

[0090] Add 50g of propyl dicyclohexyl ketone and 100mL of tetrahydrofuran to a 500mL three-necked flask and stir until dissolved at room temperature (10-20℃). Maintain the temperature below 30℃ and add 1M magnesium m-fluorophenyl bromide (250mL) dropwise. After the addition is complete below 30℃, maintain the temperature at 30-35℃ and react for 3 hours. The resulting gray solution indicates the starter has reacted completely. Cool the system to room temperature and slowly quench the reaction mixture in 100g of 3N hydrochloric acid in ice water. After quenching, extract twice with 100mL of ethyl acetate. Combine the organic phases and wash once each with 50mL of saturated sodium bicarbonate and 50mL of water. Separate the layers and dry the organic phase with anhydrous magnesium sulfate. Filter and concentrate the organic phase under reduced pressure (solvent removal temperature ≤50℃) to obtain 58g of oil, which can be used directly in the next reaction without purification.

[0091] 2) Preparation of 3CCGPCF3-2

[0092] Add 58g of 3CCGPCF3-1, 290mL of toluene, and 3.0g of p-toluenesulfonic acid monohydrate to a 500mL three-necked flask. Stir and heat to reflux for 13 hours to remove water. Take a sample for testing; the reaction of the starting materials is complete. Cool the system to room temperature and slowly add 50mL of saturated sodium bicarbonate and 50mL of water to wash once each. Concentrate and dry the organic phase under reduced pressure (concentration temperature ≤50℃): 56g of oily substance. Purity 85%, directly used for the next reaction.

[0093] 3) Preparation of 3CCGPCF3-3

[0094] Add 56g of 3CCGPCF3-2, 280mL of toluene, and 2.8g of Pd carbon (5% w / w) to a 500mL three-necked flask. Pressurize with a hydrogen balloon, stir, and heat to 30-35°C, maintaining the temperature overnight. After 20 hours of incubation, take a sample for testing; the reaction is complete. Cool the system to room temperature and filter through a funnel lined with diatomaceous earth. Concentrate and dry the filtrate under reduced pressure (T≤50°C): 56g of oily substance. Use directly for the next step.

[0095] 4) Preparation of 3CCGPCF3-4

[0096] Add 56g of 3CCGPCF3-3 and 560mL of dichloromethane to a 500mL three-necked flask and stir until dissolved at room temperature. Cool to -5 to 0°C and add 37g of aluminum trichloride in portions over 10 minutes. After adding the aluminum trichloride, maintain the reaction temperature at -5 to 0°C for 1.5 hours and send a sample for testing. Slowly pour the reaction solution into 560mL of ice water to quench the reaction, stir until dissolved at room temperature, separate the layers, wash the organic phase once with saturated sodium bicarbonate, wash the organic phase once with water, and concentrate and dry the organic phase under reduced pressure (concentration temperature ≤40°C): 54g of oily substance.

[0097] 5) Preparation of 3CCGPCF3-5

[0098] Add 37.8 g of 2,2,6,6-tetramethylpiperidine and 280 mL of tetrahydrofuran to a 1000 mL three-necked flask, stir and cool to -40°C, then add n-butyllithium (2.5 M, 108 mL) dropwise over half an hour, and keep warm for 1 hour; cool to -70°C to -80°C, then add triisopropyl borate (67 g) dropwise over half an hour, and keep warm for 1 hour; cool to -70°C to -80°C, then add 3 CCGPC dropwise. A 50 mL solution of tetrahydrofuran (F3-4, 56 g) was added dropwise over half an hour, and the reaction was maintained at -40 to -50°C for 1 hour; then at -2 to -30°C for 1 hour. TLC was performed, and the reaction proceeded completely. 200 mL of water was slowly added dropwise to quench the reaction, and the mixture was stirred at room temperature. The pH was adjusted to 2-3 with 3N hydrochloric acid. The mixture was separated, and the aqueous phase was extracted twice with 112 mL of ethyl acetate. The organic phase was concentrated under reduced pressure and dried (concentration temperature ≤50°C): 40 g of yellow solid was obtained. 112 mL of n-heptane was added, and the mixture was stirred and heated to reflux for 1 hour. Crystallization was then carried out at room temperature for 2 hours, filtered, and dried at 50°C to obtain 17.3 g of solid.

[0099] 6) Preparation of 3CCGPCF3-6

[0100] Add 17g of 3CCGPCF3-5, 12.2g of 4-bromotrifluorotoluene, 10.2g of potassium carbonate, 170mL of ethanol, and 0.34% (w / w) of catalyst to a 250mL three-necked flask. Purge with nitrogen three times and stir until reflux is reached. Maintain the reaction temperature for 20 hours. After the reactants have reacted completely, slowly pour the reaction solution into 250mL of water to quench the reaction. Extract twice with 100mL of n-heptane, separate the layers, wash the organic phase once with water, and concentrate and dry the organic phase under reduced pressure (concentration temperature ≤50℃): 18g of yellow solid. Pass the solution through a column chromatography line to obtain 15g of white solid. Add 14mL of n-heptane, stir, and heat to 60℃ to dissolve the solid. Cool to 0-5℃ to crystallize for 2 hours, filter, and obtain 6.5g of white solid, which is the target product. Purity: 99.96%.

[0101] The finished product analysis data is as follows:

[0102] 1H NMR (400MHz, CDCl3): δ=0.80-0.90(m,5H),1.00-1.50(m,13H),

[0103] 1.70-2.00(m,8H),2.48-2.55(m,1H),7.00-7.20(m,2H),7.25-7.30(m,1H),

[0104] 7.60-7.75 (m, 4H).

[0105] IR (KBr, cm-1): 2924, 2850, 2360, 2320, 1325, 1166, 1124, 1069, 840.

[0106] MS (m / z,%): 446 (M+, 100).

[0107] Example 2: Synthesis of compound B (5CCGPCF3)

[0108]

[0109] Liquid crystal compound B (5CCGPCF3) was prepared by the same synthesis method as in Example 1, except that the raw material propyl dicyclohexyl ketone (50g) in step (1) was replaced with pentyl dicyclohexyl ketone (50g), and the rest remained unchanged.

[0110] The parameter performance of liquid crystal compounds A and B synthesized in this invention was evaluated:

[0111] Compound A and compound B were dissolved in standard liquid crystal at proportions of 1%, 3%, and 5% (mass%), respectively. The mixtures were heated until clear and held for 10 minutes, then stirred at 60°C for 1 hour to ensure complete dissolution. After stirring, the mixtures were cooled to room temperature and tested at 25°C. The physical properties of compounds A and B are shown in Table 1.

[0112] Table 1. Performance of the compounds prepared in Examples 1-2 of this invention

[0113] serial number TNI Δn ne no De ε / / ε⊥ LTS (-20℃ bottle) Compound A 218.8 0.150 1.646 1.496 7.5 11.3 3.7 10D OK Compound B 220.2 0.152 1.644 1.492 7.2 10.6 3.4 10D OK

[0114] Comparative Example 1: Compound CN102633595B

[0115]

[0116] Table 2 Comparison results of liquid crystal phase transition temperature range performance tests between Examples 1-2 and Comparative Example 1.

[0117]

[0118] Analysis of the test results shows that the liquid crystal phase transition temperature range of Examples 1 and 2 is significantly wider than that of Comparative Example 1. Specifically, the phase transition temperature range of Example 1 is 9.1°C wider than that of Comparative Example 1, and the phase transition temperature range of Example 2 is 17.1°C wider than that of Comparative Example 1.

[0119] It is evident that the liquid crystal compound synthesized in this invention has a wider range of applications than other liquid crystal compounds.

[0120] Compared with conventional methods for synthesizing liquid crystal compounds (CN102633595B), the liquid crystal compound of this invention has fewer steps (reducing iodination reactions, etc.), lower cost, and is more suitable for industrial application. Simultaneously, the resulting liquid crystal compound exhibits higher resolution and a wider liquid crystal phase transition temperature range, making it better suited for preparing high-temperature liquid crystal mixtures. This liquid crystal compound is suitable as a high-temperature component in TFT mixed liquid crystals and shows great promise for application in thin-film transistor liquid crystal displays.

[0121] The following specific embodiments further illustrate the suitability of this liquid crystal compound as a high-temperature component in TFT mixed liquid crystals, but the present invention is not limited to the following embodiments. Unless otherwise specified, all methods described are conventional methods. Unless otherwise specified, all raw materials are available from publicly available commercial sources. Unless otherwise specified, all percentages are by mass.

[0122] Unless otherwise stated, percentages in this invention are weight percentages; temperature is in degrees Celsius; Δn represents optical anisotropy (25°C); Δε represents dielectric anisotropy (25°C, 1000Hz); V10 represents threshold voltage, which is the characteristic voltage (V, 25°C) when the relative transmittance changes by 10%; γ1 represents rotational viscosity (mPa.s, 25°C); Cp represents the clearing point of the liquid crystal composition (°C); K11, K22, and K33 represent the elastic constants of stretching, twisting, and bending, respectively (pN, 25°C); LTS represents the low-temperature stability of the liquid crystal, i.e., the liquid crystal is placed in a bottle and stored at low temperature.

[0123] In the following embodiments, the group structures in the liquid crystal compounds are represented by the codes shown in Table 3.

[0124] Table 3 Group structure codes of liquid crystal compounds

[0125]

[0126]

[0127] Take the following compound structure as an example:

[0128] Represented as: VCPGC3

[0129]

[0130] Represented as: 2CC1OWO2

[0131] In the following embodiments, the liquid crystal composition is prepared by a thermal dissolution method, including the following steps: weighing the liquid crystal compound by weight percentage using a balance, wherein there is no specific requirement for the order of weighing and adding, usually weighing and mixing in order of the melting point of the liquid crystal compound from high to low, heating and stirring at 60 to 120°C to make the components melt evenly, then filtering, rotary evaporating, and finally encapsulating to obtain the target sample.

[0132] In the following embodiments, the weight percentage of each component in the liquid crystal composition and the performance parameters of the liquid crystal composition are shown in the following tables.

[0133] Application Example 1:

[0134] Table 4. Weight percentage and performance parameters of each component in the liquid crystal composition.

[0135]

[0136] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0137]

[0138] Application Example 2:

[0139] Table 5. Weight percentage and performance parameters of each component in the liquid crystal composition.

[0140]

[0141]

[0142] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0143]

[0144] Application Example 3:

[0145] Table 6. Weight percentage and performance parameters of each component in the liquid crystal composition.

[0146]

[0147] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0148] Application Example 4:

[0149] Table 7. Weight percentage and performance parameters of each component in the liquid crystal composition.

[0150]

[0151] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0152]

[0153] Application Example 5:

[0154] Table 8. Weight percentage and performance parameters of each component in the liquid crystal composition.

[0155]

[0156]

[0157] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0158]

[0159] Application Example 6:

[0160] Table 9. Weight percentage and performance parameters of each component in the liquid crystal composition.

[0161]

[0162] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0163] Application Example 7:

[0164] Table 10 Weight percentage and performance parameters of each component in the liquid crystal composition

[0165]

[0166] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0167]

[0168] Application Example 8:

[0169] Table 11 Weight percentage and performance parameters of each component in the liquid crystal composition

[0170]

[0171]

[0172] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0173]

[0174] Application Example 9:

[0175] Table 12 Weight percentage and performance parameters of each component in the liquid crystal composition

[0176]

[0177]

[0178] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0179] Application Example 10:

[0180] Table 13 Weight percentage and performance parameters of each component in the liquid crystal composition

[0181]

[0182] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0183]

[0184] Application Example 11:

[0185] Table 14 Weight percentage and performance parameters of each component in the liquid crystal composition

[0186]

[0187]

[0188] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0189]

[0190] Application Example 12:

[0191] Table 15 Weight percentage and performance parameters of each component in the liquid crystal composition

[0192]

[0193]

[0194] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0195] Application Example 13:

[0196] Table 16 Weight percentage and performance parameters of each component in the liquid crystal composition

[0197]

[0198] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0199]

[0200] Application Example 14:

[0201] Table 17 Weight percentage and performance parameters of each component in the liquid crystal composition

[0202]

[0203] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0204]

[0205] Application Comparative Example 1

[0206] Table 18 Weight percentage and performance parameters of each component in the liquid crystal composition

[0207]

[0208]

[0209] The above liquid crystal composition contains 300 ppm of additives, and its structure is as follows:

[0210]

[0211] The performance parameters of the liquid crystal compositions obtained in Application Example 1 and Application Comparative Example 1 are summarized and compared, as shown in Table 19.

[0212] Table 19 Comparison of performance parameters of liquid crystal compositions

[0213] Δn Δε Cp γ1 K11 K22 K33 LTS (-20℃) Application Example 1 0.1266 5.93 106.06 63.8 14.9 7.5 17.6 10D OK Application Comparative Example 1 0.1100 4.45 92.05 63.5 15.3 7.6 20.2 10D OK

[0214] The comparison shows that, compared with Comparative Example 1, Application Example 1 with Compound A added has a significantly higher clearing point, greater dielectric anisotropy and refractive index. Meanwhile, there is little difference between the two in terms of viscosity and low temperature.

[0215] The liquid crystal compound provided by this invention has a simpler synthesis method, which can significantly reduce the synthesis cost; at the same time, the compound also has a high clearing point, a large refractive index, and excellent light stability and thermal stability, making it suitable for IPS and FFS type liquid crystal displays and effectively improving liquid crystal displays.

[0216] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A high-temperature tetracyclic liquid crystal compound, the structure of which is shown in general formula I: in, R1 represents H, a C1-C12 alkyl group, or a C2-C12 alkylene group, wherein one or more CH2 groups can be independently converted to hydrogen. -CF=CH-, -CF=CF-, -CH=CF-, -COO- or -O- substitution; X is represented as CF3 or OCF3.

2. The high-temperature tetracyclic liquid crystal compound according to claim 1, characterized in that: R1 represents an alkyl group with 1 to 9 carbon atoms, a fluorinated alkyl group with 1 to 9 carbon atoms, an alkoxy group with 1 to 9 carbon atoms, a fluorinated alkoxy group with 1 to 9 carbon atoms, an alkenyl group with 2 to 9 carbon atoms, a fluorinated alkenyl group with 2 to 9 carbon atoms, an alkenyl group with 3 to 8 carbon atoms, or a fluorinated alkenyl group with 3 to 8 carbon atoms; X represents CF3 or OCF3.

3. The method for preparing the high-temperature tetracyclic liquid crystal compound according to claim 1 or 2, comprising the following steps: 1) Preparation of CCGPCF3-1 Dicyclohexyl ketone and tetrahydrofuran were dissolved by stirring at room temperature. Magnesium m-fluorophenyl bromide was added dropwise while maintaining the temperature below 30°C. After the addition was complete, the temperature was maintained at 30-35°C for 3 hours. The resulting gray solution was observed on a TLC plate after the initial reaction was complete. The system was cooled to room temperature, and the reaction solution was slowly poured into an ice-water solution of hydrochloric acid to quench the reaction. After quenching, ethyl acetate was added for extraction twice. The combined organic phases were washed once each with saturated sodium bicarbonate and water. The mixture was separated, and the organic phase was dried over anhydrous magnesium sulfate. After filtration, the organic phase was concentrated and dried under reduced pressure to obtain an oily substance. 2) Preparation of CCGPCF3-2 Toluene and p-toluenesulfonic acid monohydrate were added to CCGPCF3-1, stirred and heated to reflux to separate water, and a sample was taken for testing. The reaction of the raw materials was complete. The system was cooled to room temperature, and saturated sodium bicarbonate and water were slowly poured in to wash once each. The organic phase was concentrated and dried under reduced pressure to obtain an oily substance. 3) Preparation of CCGPCF3-3 Toluene and Pd carbon were added to CCGPCF3-2, pressurized with a hydrogen balloon, stirred and heated to 30-35℃, and reacted overnight. Samples were taken and sent for testing after the raw materials had reacted completely. The system was cooled to room temperature, and filtered through a funnel lined with diatomaceous earth. The filtrate was concentrated and dried under reduced pressure to obtain an oily substance. 4) Preparation of CCGPCF3-4 Dichloromethane was added to CCGPCF3-3 and stirred until dissolved at room temperature. The temperature was lowered to -5 to 0°C, and aluminum trichloride was added in batches. After the addition was complete, the reaction was kept at -5 to 0°C and a sample was sent for testing. The reaction solution was slowly poured into ice water to quench it, stirred until dissolved at room temperature, and separated. The organic phase was washed once with saturated sodium bicarbonate and once with water. The organic phase was concentrated and dried under reduced pressure to obtain an oily substance. 5) Preparation of CCGPCF3-5 2.2.6.6-Tetramethylpiperidine and tetrahydrofuran were stirred and cooled to -40°C. Butyllithium was added dropwise, and the mixture was kept at this temperature after the addition was complete. The mixture was then cooled to -70°C to -80°C, and triisopropyl borate was added dropwise. After the addition was complete, the mixture was kept at this temperature. The mixture was then cooled to -70°C to -80°C, and a tetrahydrofuran solution of CCGPCF3-4 was added dropwise. After the addition was complete, the mixture was kept at -40°C to -50°C, and then at -2°C to -30°C. The mixture was then spotted onto a TLC plate, and the reaction was complete. Water was slowly added to quench the reaction, and the mixture was stirred at room temperature. The pH was adjusted to 2-3 with hydrochloric acid. The mixture was separated into liquid and liquid phases. The aqueous phase was extracted twice with ethyl acetate, and the organic phase was concentrated and dried under reduced pressure to obtain a yellow solid. Heptane was added, and the mixture was stirred and heated to reflux to form a slurry. The mixture was cooled to room temperature to crystallize, filtered, and dried. 6) Preparation of CCGPCF3-6 Add 4-bromotrifluorotoluene, potassium carbonate, ethanol, and catalyst to CCGPCF3-5, purge with nitrogen, stir and heat to reflux; maintain the temperature for reaction, after the reactants have reacted, slowly pour the reaction solution into water to quench, add n-heptane for extraction, separate the liquids, wash the organic phase once with water, concentrate and dry the organic phase under reduced pressure to obtain a yellow solid; pass n-heptane through a column to obtain a white solid; add n-heptane and stir to heat until dissolved, cool to 0-5℃ to crystallize, filter to obtain a white solid.

4. The application of the high-temperature tetracyclic liquid crystal compound according to claim 1 or 2 in a liquid crystal composition.

5. The application according to claim 4, characterized in that: The high-temperature tetracyclic liquid crystal compound is used as the high-temperature component of the TFT mixed liquid crystal.

6. The application according to claim 5, characterized in that: Application of liquid crystal compositions containing high-temperature tetracyclic liquid crystal compounds in thin-film transistor liquid crystal displays.

7. A liquid crystal composition comprising the high-temperature tetracyclic liquid crystal compound of claim 1 or 2.

8. The liquid crystal composition according to claim 7, characterized in that: The liquid crystal composition comprises one or more compounds represented by general formula I, in a mass percentage content of 0.1%-10%; One or more compounds represented by general formula II, in a mass percentage content of 5%-85%; R2 and R3 are independently represented as alkyl with 1 to 9 carbon atoms, fluorinated alkyl with 1 to 9 carbon atoms, alkoxy with 1 to 9 carbon atoms, fluorinated alkoxy with 1 to 9 carbon atoms, alkenyl with 2 to 9 carbon atoms, fluorinated alkenyl with 2 to 9 carbon atoms, alkenyl with 3 to 8 carbon atoms, or fluorinated alkenyl with 3 to 8 carbon atoms. A1, A2, and A3 can be represented independently as follows: m represents 0 or 1; And one or more compounds represented by general formula III, in a mass percentage content of 5%-85%; R4 and R6 are independently represented as alkyl with 1 to 9 carbon atoms, fluorinated alkyl with 1 to 9 carbon atoms, alkoxy with 1 to 9 carbon atoms, fluorinated alkoxy with 1 to 9 carbon atoms, alkenyl with 2 to 9 carbon atoms, fluorinated alkenyl with 2 to 9 carbon atoms, alkenyl with 3 to 8 carbon atoms, or fluorinated alkenyl with 3 to 8 carbon atoms. R5 is represented as -CF2O-, a single bond, or -CH2O-; n represents 0 or 1.

9. The liquid crystal composition according to claim 8, characterized in that: The liquid crystal compound represented by general formula II is one or more of the following structural compounds: R2 and R3 are each independently represented as an alkyl group having 1 to 9 carbon atoms, a fluorinated alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a fluorinated alkoxy group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, a fluorinated alkenyl group having 2 to 9 carbon atoms, an alkenyl group having 3 to 8 carbon atoms, or a fluorinated alkenyl group having 3 to 8 carbon atoms. The liquid crystal compound represented by general formula III is one or more of the following structural compounds:

10. The liquid crystal composition according to claim 9, characterized in that: The liquid crystal composition further comprises nematic liquid crystal, smectic liquid crystal, cholesterol liquid crystal, antioxidant, ultraviolet absorber, infrared absorber, polymerizable monomer and / or light stabilizer.

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