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Preparation method of biphenyl liquid crystal material

A technology of liquid crystal materials and biphenyls, which is applied in the field of preparation of biphenyl liquid crystal materials, can solve the problems of complex post-processing purification, complex purification of final products, and reduction of resistivity of liquid crystal materials.

Active Publication Date: 2019-04-16
SUPERD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the suzuki reaction also has some unavoidable disadvantages, such as the catalyst metal palladium is not easy to remove, and the residual metal palladium will greatly reduce the resistivity of the liquid crystal material and affect its response voltage in the display device; another example is the reaction substrate boric acid Self-coupling by-products are generated under suzuki reaction conditions, complicating work-up purification
Especially when preparing cyano (CN) and isothionitrile (NCS) liquid crystal monomers, due to the self-coupling by-products and the final product CN, the polarity of the NCS liquid crystal monomers is very close, and the self-coupling product and the final product When they are mixed together, it is difficult to separate them by column chromatography, which makes the purification of the final product complicated. Therefore, before the step of preparing the final reaction product CN and NCS liquid crystal monomer, the self-coupling by-product must be removed to ensure the purity of the final product
[0008] At present, the commonly used purification method for post-treatment of suzuki is column chromatography, which uses the different polarities of the product and the by-product to separate the product and the by-product, so as to achieve the purpose of purification, but due to the column chromatography in When the amount of preparation becomes larger, the required preparation time, separation time and elution solvent will be greatly increased, and the corresponding column chromatography column will also be enlarged, which is very unfavorable for industrial mass production

Method used

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  • Preparation method of biphenyl liquid crystal material
  • Preparation method of biphenyl liquid crystal material
  • Preparation method of biphenyl liquid crystal material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] This example is Preparation of:

[0046] Step 1), synthesize target product:

[0047]

[0048] Build a reflux reaction device, put a stirring bar into the reaction bottle, add 4-propylbiphenylboronic acid, 2,6-difluoro-4-bromoaniline, catalyst Pd(Pph 3 ) 4 ,, cesium carbonate; seal the reaction system, replace the air in the sealed system with nitrogen; inject N,N-dimethylformamide and water, stir and slowly heat to reflux to ensure that the system reacts under the protection of nitrogen. After 4 hours, the extent of the reaction was checked by TLC.

[0049] Step 2), the product of step 1) is purified with a Soxhlet extractor:

[0050] After the reaction is complete, pour the reaction solution into ice water, add dilute hydrochloric acid dropwise and stir until neutral, so that all the sodium carbonate in the reaction solution has reacted; extract the above liquid with dichloromethane, collect the organic phase, and obtain the organic phase Wash twice with brin...

Embodiment 2

[0062] This example is Preparation of:

[0063] Step 1), synthesize target product:

[0064]

[0065] Build a reflux reaction device, put a stirring bar into the reaction bottle, add 2,6-difluoro-4-chloroaniline, catalyst Pb(dppf)Cl 2 and potassium carbonate; seal the reaction system, replace the air in the sealed system with nitrogen; inject 1,4-dioxane and water, stir and slowly heat to reflux to ensure that the system reacts under nitrogen protection. After 5 hours, the extent of the reaction was checked by TLC.

[0066] Step 2), the product of step 1) is purified with a Soxhlet extractor:

[0067] After the reaction is complete, pour the reaction solution into ice water, add dilute hydrochloric acid dropwise and stir until neutral, so that all the sodium carbonate in the reaction solution has reacted; extract the above liquid with dichloromethane, collect the organic phase, and obtain the organic phase Wash twice with brine, then dry with anhydrous sodium sulfate...

Embodiment 3

[0074] This example is Preparation of:

[0075] Step 1), prepare final product:

[0076]

[0077] Set up the reflux reaction device, put into stirring bar in the reaction bottle, add 4-propylphenylboronic acid, 4-iodoaniline, catalyst Pd(Pph 3 ) 2 Cl 2 , sodium carbonate; seal the reaction system, replace the air in the sealed system with nitrogen; inject isopropanol and water, stir and slowly heat to reflux to ensure that the system reacts under the protection of nitrogen. After 2 hours, the extent of the reaction was checked by TLC.

[0078] Step 2), the product of step 1) is purified with a Soxhlet extractor:

[0079] After the reaction is complete, pour the reaction solution into ice water, add dilute hydrochloric acid dropwise and stir until neutral, so that all the sodium carbonate in the reaction solution has reacted; extract the above liquid with dichloromethane, collect the organic phase, and obtain the organic phase Wash twice with brine, then dry with anhy...

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Abstract

The invention provides a preparation method of a biphenyl liquid crystal material. The biphenyl liquid crystal material is shown in the formula I. The biphenyl liquid crystal material is prepared through the following steps, including, 1) synthesis, comprising in a first organic solvent, heating a compound shown in the formula II, a compound shown in the formula III and alkali in the action of a catalyst for a Suzuki reaction shown in the description, wherein R1 is -F or -NH2, R2 is alkyl having 3-7 carbon atoms, unsaturated alkyl having 3-7 carbon atoms, or alkoxy having 3-7 carbon atoms, L1, L2, L3 and L4 are H or F, respectively, m is 0, 1 or 2, X is -Cl, -Br, or -I, and a structure shown in the description is cyclohexylidene, phenylene, or 2,4-disubstituted pyrimidine; and 2) purification, including purifying the reaction product obtained in the step 1) with a soxhlet extractor after the Suzuki reaction is finished. The preparation and purification method of a biphenyl liquid crystal material is simple in instruments, convenient to operate, saved in time, high in purity and less in loss.

Description

technical field [0001] The invention relates to the field of liquid crystal materials, in particular to a method for preparing biphenyl liquid crystal materials. Background technique [0002] Stereoscopic display is the development direction of the display field, especially glasses-free 3D display will be the mainstream trend of 3D display. [0003] In a naked-eye 3D display device, a light-splitting device is needed to accurately transmit the differentiated pixel information in the display to the left and right eyes of a person. Commonly used light-splitting devices include lenses, slits, and the like. Lenses can be roughly divided into two types. One has the conventional physical shape of the lens, such as a curved surface structure. It is often prepared by UV polymerization or thermal polymerization using polymerizable anisotropic optical materials, but it is not suitable for mass production. And the yield rate is low; the other is a liquid crystal lens, which sandwiches...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C331/28C07D239/26C07C211/45C07C209/68C07C255/50C07C255/54C07C253/00C07C25/18C07C17/263C09K19/12C09K19/34C09K19/30
Inventor 张国贤包瑞
Owner SUPERD CO LTD