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Preparation method of negative liquid crystal compound

A technology of negative liquid crystals and compounds, which is applied in the field of preparation of negative liquid crystal compounds, can solve problems such as limited application range, poor miscibility, and poor stability, and achieve the effects of cost reduction, less impurities, and moderate refractive index

Active Publication Date: 2018-03-09
HEBEI MAIERSTON ELECTRONICS MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In the literature Mol.Cryst.Liq.Cryst., 1983, Vol.94, pp109-118 mentions liquid crystal ester compounds containing dicyano groups in the side position, such as This type of compound has large negative dielectric anisotropy, but also has disadvantages such as high viscosity, low resistivity, poor stability and poor miscibility, which limit its application range.

Method used

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  • Preparation method of negative liquid crystal compound
  • Preparation method of negative liquid crystal compound
  • Preparation method of negative liquid crystal compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Embodiment 1, preparation

[0052] (1) Put 58.5g of 2,3-difluorophenetole (compound a-1), 42g of potassium tert-butoxide and 500ml of tetrahydrofuran into a 1000ml four-necked bottle. Under the protection of nitrogen, lower the temperature to -90~-100°C, add 200ml of 2.5mol / L butyllithium solution dropwise, and then keep the temperature for 1.5h. Add 30g of N,N-dimethylformamide dropwise at -90~-100°C. Slowly rise to room temperature and stir for 3h. The feed solution was poured into hydrochloric acid ice water for hydrolysis, extracted with ethyl acetate, dried, and passed through a silica gel column to obtain 4-ethoxy-2,3-difluorobenzaldehyde (compound 1-1) with a purity of 97.5% (GC), Yield 84%. Its reaction formula is as follows:

[0053]

[0054] (2) Put 170g of methyl bromide triphenylphosphine salt and 500ml of tetrahydrofuran into a 1000ml four-necked bottle. Under the protection of nitrogen, 58 g of potassium tert-butoxide was added at 0°C, and then k...

Embodiment 2

[0059] Embodiment 2, preparation

[0060] The preparation of intermediate B-1 is the same as in Example 1. Then, 18.4g of compound b-2, 19g of 4-ethoxy-2,3-difluorostyrene (intermediate B-1), and 400ml of DMSO were added into a 500ml four-necked flask. Under the protection of nitrogen, the temperature was lowered to 0°C, 1.2 g of potassium tert-butoxide was added, and the temperature was kept for 12 hours. Pour into acid water for hydrolysis, extract with ethyl acetate, neutralize, dry, and evaporate the solvent to dryness. Use petroleum ether to pass through a silica gel column, and crystallize with ethanol to obtain a negative liquid crystal compound represented by formula (I-9), with a purity of 99.5% and a yield of 50%. Its reaction formula is as follows:

[0061]

[0062] The structure of the negative liquid crystal compound shown in the formula (I-9) was confirmed, and its hydrogen nuclear magnetic resonance spectrum is as follows image 3 As shown, its mass spe...

Embodiment 3

[0063] Embodiment 3, preparation

[0064] (1) Put 58.5g of compound a-3, 42g of potassium tert-butoxide and 500ml of tetrahydrofuran into a 1000ml four-necked bottle. Under the protection of nitrogen, lower the temperature to -90~-100°C, add 200ml of 2.5mol / L butyllithium solution dropwise, and then keep the temperature for 1.5h. Add 30g of N,N-dimethylformamide dropwise at -90~-100°C. Slowly rise to room temperature and stir for 3h. The feed solution was poured into hydrochloric acid ice water for hydrolysis, extracted with ethyl acetate, dried, and passed through a silica gel column to obtain compound 1-3 with a purity of 97.5% (GC) and a yield of 84%. Its reaction formula is as follows:

[0065]

[0066] (2) Put 170g of methyl bromide triphenylphosphine salt and 500ml of tetrahydrofuran into a 1000ml four-necked bottle. Under the protection of nitrogen, 58 g of potassium tert-butoxide was added at 0°C, and then kept for 15 minutes. A solution of 80 g of compound 1...

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Abstract

The invention belongs to the technical field of liquid crystal compounds, and relates to a preparation method of a negative liquid crystal compound. The preparation method comprises the following steps: (1) by taking a compound a as a raw material, carrying out reaction under existence of BuLi / DMF to obtain a compound 1; (2) under existence of triphenylphosphine bromide / potassium tert-butoxide, carrying out one-step reaction on the compound 1 to obtain an intermediate B; (3) by taking a compound b as a raw material, under a condition that an alkaline reagent and a reaction solvent exist, carrying out reaction on the compound b and the obtained intermediate B to obtain the negative liquid crystal compound as shown in Formula (I). The synthesis route of the method is obviously shortened, andthe related reactions can be all quantitatively and completely implemented; the quantity of impurities is small, and the intermediate is liable to decompress, distill and purify, so that mass production is facilitated, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of liquid crystal compounds, and in particular relates to a preparation method of negative liquid crystal compounds. Background technique [0002] In the past ten years, liquid crystal display technology has developed rapidly, and liquid crystal display products have been rapidly popularized in people's ordinary lives. New liquid crystal display methods mainly include optically compensated bending mode (OCB), in-plane transition liquid crystal display (IPS), vertical alignment mode (VA), axisymmetric microstructure liquid crystal display (ASM), multi-domain twisted liquid crystal display, etc. The liquid crystal cells of various display methods have different designs and different driving methods. The direction of the liquid crystal molecular director and the glass substrate is different. The direction of the optically compensated bending mode (OCB) and the in-plane transition liquid crystal display (IPS) li...

Claims

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Application Information

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IPC IPC(8): C09K19/30C09K19/34
CPCC09K19/3028C09K19/3402C09K2019/3036C09K2019/3037C09K2019/304C09K2019/3422
Inventor 葛会军仲锡军
Owner HEBEI MAIERSTON ELECTRONICS MATERIAL
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