Synthesis and application of liquid crystal compound containing alkoxy dicyclohexyl polyfluorobenzene

Abstract

The invention belongs to the technical field of liquid crystal materials, and particularly relates to synthesis and application of a liquid crystal compound containing alkoxy dicyclohexyl polyfluorobenzene. Comprising the following steps: S1, adding butyl lithium into 2, 3-difluorophenetole under anaerobic low-temperature conditions for reaction, then adding propyl dicyclohexyl ketone, and synthesizing an intermediate I through low-temperature reaction; s2, reacting the intermediate I with p-toluenesulfonic acid under a heating condition to synthesize an intermediate II; s3, synthesizing an intermediate III from the intermediate II and a catalyst through hydrogenation reaction under certain conditions; and S4, finally, carrying out transposition reaction on the intermediate III by using aluminum trichloride to obtain a product IV. The production cost is low, the production conditions are relatively mild, the safety is high, the synthesized alkoxy dicyclohexyl polyfluorobenzene liquid crystal compound is high in quality, the chemical purity can reach 99.99%, and the content of long impurities is below 10 ppm.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid crystal materials, and in particular relates to the synthesis and application of a liquid crystal compound containing alkoxydicyclohexylpolyfluorobenzene. Background Art

[0002] Liquid crystal material (LCM) is a material in a state between liquid and crystalline, combining the fluidity of a liquid with the birefringence and anisotropy of a crystal. In recent years, the application of LC materials has significantly expanded to include various display devices, electro-optical devices, electronic components, sensors, and more. Nematic LC compounds have been most widely used in flat-panel displays, particularly in TFT active-matrix systems.

[0003] Among them, "active matrix" includes two types: 1. OMS (metal oxide semiconductor) or other diodes on a silicon wafer as a substrate. 2. Thin film transistors (TFTs) on a glass plate as a substrate. Single crystal silicon as a substrate material limits the display size because many problems arise at the joints of the various display components and even the module assembly. Therefore, the second type of thin film transistor is a promising active matrix type, and the photoelectric effect used is usually the TN effect. TFTs include compound semiconductors, or TFTs based on polycrystalline or amorphous silicon.

[0004] In recent years, as touch screens have become mainstream in the mobile device market, IPS and FFS hard-screen displays have inherent advantages. IPS and FFS displays can use both positive and negative liquid crystals. Due to the curved electric field present in these displays, positive liquid crystals align along the electric field lines, causing molecular bending and a decrease in transmittance. Negative liquid crystals align perpendicular to the electric field lines, significantly increasing transmittance. This is currently the best method for increasing transmittance and reducing backlight power consumption. However, the response time issue with negative liquid crystals is a major challenge currently encountered. FFS displays using negative liquid crystals have a response time that is 50% or more slower than those using positive liquid crystals. Therefore, how to improve the response time of negative liquid crystals has become a core issue.

[0005] Specifically, the response time of a liquid crystal display depends on the thickness of the liquid crystal layer, the rotational viscosity of the liquid crystal, and the effective elastic constant. Therefore, reducing the rotational viscosity, reducing the thickness of the liquid crystal layer, and increasing the elastic constant can all achieve the purpose of improving the response time. The thickness of the liquid crystal layer depends on the design of the liquid crystal display. Therefore, for liquid crystal compositions, reducing the rotational viscosity and liquid crystal thickness are most effective.

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a liquid crystal compound containing an alkoxy group and a polyfluorobiphenyl structure, which has a specific fast response characteristic. Summary of the Invention

[0007] The purpose of the present invention is to solve the existing problems and provide a synthesis and application of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene.

[0008] The present invention is achieved through the following technical solutions:

[0009] A synthesis of a liquid crystal compound containing alkoxydicyclohexylpolyfluorobenzene comprises the following steps:

[0010] S1. Add butyl lithium to 2,3-difluorophenyl ether in the absence of oxygen and at low temperature, then add propyl dicyclohexyl ketone to synthesize intermediate I through low temperature reaction;

[0011] S2. Intermediate I is reacted with p-toluenesulfonic acid under heating conditions to synthesize intermediate II;

[0012] S3, synthesizing intermediate III by hydrogenation reaction using intermediate II and a catalyst at a hydrogen pressure of 1.0-1.5 MPa and a temperature of 40±5°C;

[0013] S4. Finally, intermediate III is subjected to a transposition reaction with aluminum chloride at -5±5°C to obtain product IV.

[0014] Furthermore, the oxygen-free low-temperature condition in step S1 is -40 to -85°C, and butyl lithium is added to react for 4 to 7 hours.

[0015] Furthermore, the intermediate I described in step S1 is 1-(p-propyl-dicyclohexyl alcohol)-(4-ethoxy)-2,3-difluorobenzene;

[0016] The molar ratio of the 2,3-difluorophenethyl ether, butyl lithium and propyl dicyclohexyl ketone is 1:1.1:1.05.

[0017] Furthermore, the heating temperature in step S2 is 50±5° C., and the reaction time is 4 to 6 h.

[0018] Furthermore, the intermediate II described in step S2 is 1-(p-propyl-dicyclohexylene)-(4-ethoxy)-2,3-difluorobenzene;

[0019] The molar ratio of the intermediate I to p-toluenesulfonic acid is 1:0.15.

[0020] Furthermore, the catalyst in step S3 is a Pd / C catalyst.

[0021] Furthermore, the intermediate III described in step S3 is 1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene;

[0022] The mass ratio of the intermediate II to Pd / C is 1:0.005.

[0023] Furthermore, the product IV described in step S4 is trans-1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene.

[0024] Furthermore, the molar ratio of the intermediate III to aluminum chloride in step S4 is 1:1.3.

[0025] Furthermore, the structural formula of the product IV is:

[0026]

[0027] Compound formula: C 23 H 34 OF2

[0028] MS:364.52g / moL;

[0029] The reaction process is as follows:

[0030]

[0031] The invention discloses an application of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene in display devices, electro-optical devices, electronic components and sensors.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. The production cost of the present invention is low, and the raw materials are all large industrial products, so that the product price is reduced by about 1,000 yuan / kg compared with the average price of most original monomers.

[0034] 2. The production conditions of the present invention are relatively mild, the reaction types involved are all common reactions, and the reaction types and unit operations are mature.

[0035] 3. The product of the present invention is non-hazardous chemical and can be stored under normal conditions (normal room temperature storage is sufficient and will not be affected by weather changes), so it is highly safe.

[0036] 4. The alkoxybiscyclohexylpolyfluorobenzene liquid crystal compound synthesized by the present invention has high quality, chemical purity can reach 99.99%, and impurities are below 10 ppm. DETAILED DESCRIPTION

[0037] In order to further explain the present invention, it is described below with reference to the following specific embodiments.

[0038] Example 1

[0039] A synthesis of a liquid crystal compound containing alkoxydicyclohexylpolyfluorobenzene comprises the following steps:

[0040] S1. Add butyl lithium to 2,3-difluorophenyl ether at -40°C in the absence of oxygen for 4 h, then slowly add propyl dicyclohexyl ketone to synthesize intermediate I (1-(p-propyl-dicyclohexyl alcohol)-(4-ethoxy)-2,3-difluorobenzene) through a low-temperature reaction at -40°C.

[0041] The molar ratio of 2,3-difluorophenethyl ether, butyl lithium, and propyl dicyclohexyl ketone is 1:1.1:1.05;

[0042] S2. Intermediate I and p-toluenesulfonic acid are reacted at 45°C for 4 h to synthesize intermediate II (1-(p-propyl-dicyclohexylene)-(4-ethoxy)-2,3-difluorobenzene);

[0043] The molar ratio of the intermediate I to p-toluenesulfonic acid is 1:0.15;

[0044] S3. Intermediate III (1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene) was synthesized by hydrogenation reaction using intermediate II and Pd / C catalyst at a hydrogen pressure of 1.0 MPa and 35°C.

[0045] The mass ratio of the intermediate II to Pd / C is 1:0.005;

[0046] S4. Finally, the intermediate III is subjected to a transposition reaction with aluminum chloride at -5°C to obtain the product IV (trans-1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene).

[0047] The molar ratio of the intermediate III to aluminum chloride is 1:1.3;

[0048] The structural formula of the product IV is:

[0049]

[0050] Compound formula: C 23 H 34 OF2

[0051] MS:364.52g / moL;

[0052] The reaction process is as follows:

[0053]

[0054] The chemical purity of the product was found to be 99.99%, with impurities below 10 ppm.

[0055] Example 2

[0056] A synthesis of a liquid crystal compound containing alkoxydicyclohexylpolyfluorobenzene comprises the following steps:

[0057] S1. Add butyl lithium to 2,3-difluorophenyl ether at -60°C in the absence of oxygen for 5 h, then slowly add propyl dicyclohexyl ketone to synthesize intermediate I (1-(p-propyl-dicyclohexyl alcohol)-(4-ethoxy)-2,3-difluorobenzene) through a low-temperature reaction at -60°C.

[0058] The molar ratio of 2,3-difluorophenethyl ether, butyl lithium, and propyl dicyclohexyl ketone is 1:1.1:1.05;

[0059] S2. Intermediate I and p-toluenesulfonic acid are reacted at 50°C for 5 h to synthesize intermediate II (1-(p-propyl-dicyclohexylene)-(4-ethoxy)-2,3-difluorobenzene);

[0060] The molar ratio of the intermediate I to p-toluenesulfonic acid is 1:0.15;

[0061] S3. Intermediate III (1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene) was synthesized by hydrogenation reaction using intermediate II and Pd / C catalyst at a hydrogen pressure of 1.2 MPa and 40°C.

[0062] The mass ratio of the intermediate II to Pd / C is 1:0.005;

[0063] S4. Finally, the intermediate III is subjected to a transposition reaction with aluminum chloride at 0°C to obtain the product IV (trans-1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene).

[0064] The molar ratio of the intermediate III to aluminum chloride is 1:1.3;

[0065] The structural formula of the product IV is:

[0066]

[0067] Compound formula: C 23 H 34 OF2

[0068] MS:364.52g / moL;

[0069] The reaction process is as follows:

[0070]

[0071] The chemical purity of the product was found to be 99.99%, with impurities below 10 ppm.

[0072] Example 3

[0073] A synthesis of a liquid crystal compound containing alkoxydicyclohexylpolyfluorobenzene comprises the following steps:

[0074] S1. Add butyl lithium to 2,3-difluorophenyl ether at -85°C in the absence of oxygen for 4-7 hours, then slowly add propyl dicyclohexyl ketone to synthesize intermediate I (1-(p-propyl-dicyclohexyl alcohol)-(4-ethoxy)-2,3-difluorobenzene) through a low-temperature reaction at -85°C.

[0075] The molar ratio of 2,3-difluorophenethyl ether, butyl lithium, and propyl dicyclohexyl ketone is 1:1.1:1.05;

[0076] S2. Intermediate I and p-toluenesulfonic acid are reacted at 55°C for 6 h to synthesize intermediate II (1-(p-propyl-dicyclohexylene)-(4-ethoxy)-2,3-difluorobenzene);

[0077] The molar ratio of the intermediate I to p-toluenesulfonic acid is 1:0.15;

[0078] S3. Intermediate III (1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene) was synthesized by hydrogenation reaction using intermediate II and Pd / C catalyst at a hydrogen pressure of 1.0-1.5 MPa and a temperature of 40±5°C.

[0079] The mass ratio of the intermediate II to Pd / C is 1:0.005;

[0080] S4. Finally, the intermediate III is subjected to a transposition reaction with aluminum chloride at 5°C to obtain the product IV (trans-1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene).

[0081] The molar ratio of the intermediate III to aluminum chloride is 1:1.3;

[0082] The structural formula of the product IV is:

[0083]

[0084] Compound formula: C 23 H 34 OF2

[0085] MS:364.52g / moL;

[0086] The reaction process is as follows:

[0087]

[0088] The chemical purity of the product was found to be 99.99%, with impurities below 10 ppm.

[0089] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene, characterized in that: The steps include: S1. Add butyl lithium to 2,3-difluorophenyl ether in the absence of oxygen and at low temperature, then add propyl dicyclohexyl ketone to synthesize intermediate I through low temperature reaction; S2. Intermediate I is reacted with p-toluenesulfonic acid under heating conditions to synthesize intermediate II; S3, synthesizing intermediate III by hydrogenation reaction using intermediate II and a catalyst at a hydrogen pressure of 1.0-1.5 MPa and a temperature of 40±5°C; S4. Finally, intermediate III is subjected to a transposition reaction with aluminum chloride at -5±5°C to obtain product IV.

2. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The oxygen-free low-temperature condition in step S1 is -40 to -85°C, and butyl lithium is added to react for 4 to 7 hours.

3. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The intermediate I described in step S1 is 1-(p-propyl-dicyclohexyl alcohol)-(4-ethoxy)-2,3-difluorobenzene; The molar ratio of the 2,3-difluorophenethyl ether, butyl lithium and propyl dicyclohexyl ketone is 1:1.1:1.

05.

4. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The heating temperature in step S2 is 50±5° C., and the reaction time is 4 to 6 h.

5. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The intermediate II described in step S2 is 1-(p-propyl-dicyclohexylene)-(4-ethoxy)-2,3-difluorobenzene; The molar ratio of the intermediate I to p-toluenesulfonic acid is 1:0.

15.

6. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The catalyst described in step S3 is a Pd / C catalyst.

7. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The intermediate III described in step S3 is 1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene; The mass ratio of the intermediate II to Pd / C is 1:0.

005.

8. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The product IV described in step S4 is trans-1-(p-propyl-dicyclohexyl)-(4-ethoxy)-2,3-difluorobenzene.

9. The synthesis of a liquid crystal compound containing alkoxybiscyclohexylpolyfluorobenzene according to claim 1, characterized in that: The molar ratio of intermediate III to aluminum chloride in step S4 is 1:1.

3.

10. Use of the alkoxybiscyclohexylpolyfluorobenzene-containing liquid crystal compound synthesized and prepared by the method according to any one of claims 1 to 9 in display devices, electro-optical devices, electronic components, and sensors.

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