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Synthetic method of cyano-biphenyl type liquid crystal material

A technology of liquid crystal materials and synthesis methods, which is applied in the direction of liquid crystal materials, chemical instruments and methods, and the preparation of organic compounds. It can solve the problems of low yield, many by-products, and expensive organic lithium reagents, and achieve simple post-reaction treatment. , simple reaction operation, reduced equipment investment and production costs

Inactive Publication Date: 2012-06-27
LANZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, method one has a low yield and needs to be operated at a lower temperature; method two generally requires low temperature operation below -78°C, and the organolithium reagent is expensive and dangerous to operate
Both have brought greater difficulty to mass industrial production and increased costs
The traditional method of synthesizing cyanoterphenyl-type liquid crystal materials is mainly to use alkyl terphenyls to generate corresponding amides and then dehydrate them. This synthesis process has the disadvantages of high cost, long steps, many by-products, and difficult operation of the reaction.

Method used

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  • Synthetic method of cyano-biphenyl type liquid crystal material
  • Synthetic method of cyano-biphenyl type liquid crystal material
  • Synthetic method of cyano-biphenyl type liquid crystal material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1: Synthesis of 4'-pentyloxy-4-cyanodiphenyl

[0027] Under nitrogen protection, 20 mmol of 4-bromobenzonitrile, 0.1 mmol of palladium acetate, 0.12 mmol of Ph 3 P and 2 mmol of zinc bromide were dissolved in 30 ml of THF, and then 50 ml of Grignard reagent prepared from 20 mmol of 4-pentyloxybromobenzene was added dropwise. After the addition was completed, the mixture was reacted at room temperature for 2 hours. Afterwards, the reaction solution was cooled in an ice-water bath, and then 50 ml of 1% by mass dilute saline solution was added dropwise, stirred for 30 minutes after the dropwise addition, and the organic phase was separated, and the aqueous phase was extracted twice with 50 ml of ethyl acetate, and the organic phases were combined , and washed twice with 50 ml of water, the solvent was evaporated in a rotary evaporator to obtain a crude product. The crude product was recrystallized with methanol and decolorized with activated carbon to obtain pure ...

Embodiment 2

[0029] Example 2: Synthesis of 4'-pentyloxy-4-cyanodiphenyl

[0030] Under nitrogen protection, 20 mmol of 4-bromobenzonitrile, 0.2 mmol of palladium acetate, 0.24 mmol of Ph 3 P and 3 mmol of zinc bromide were dissolved in 30 ml of THF, and then 50 ml of Grignard reagent prepared from 20 mmol of 4-pentyloxybromobenzene was added dropwise. After the addition was completed, the reaction was carried out at room temperature for 2 hours. Afterwards, the reaction solution was cooled in an ice-water bath, and then 50 ml of 1% by mass dilute saline solution was added dropwise, stirred for 30 minutes after the dropwise addition, and the organic phase was separated, and the aqueous phase was extracted twice with 50 ml of ethyl acetate, and the organic phases were combined , and washed twice with 50 ml of water, the solvent was evaporated in a rotary evaporator to obtain a crude product. The crude product was recrystallized with methanol and decolorized with activated carbon to obtain ...

Embodiment 3

[0031] Example 3: Synthesis of 4'-pentyloxy-4-cyanobiphenyl

[0032] Under nitrogen protection, 20 mmol of 4-bromobenzonitrile, 0.4 mmol of palladium acetate, 0.48 mmol of Ph 3P and 4 mmol of zinc bromide were dissolved in 30 ml of THF, and then 50 ml of Grignard reagent prepared from 20 mmol of 4-pentyloxybromobenzene was added dropwise. After the addition was completed, the mixture was reacted at room temperature for 2 hours. Afterwards, the reaction solution was cooled in an ice-water bath, and then 50 ml of 1% by mass dilute saline solution was added dropwise, stirred for 30 minutes after the dropwise addition, and the organic phase was separated, and the aqueous phase was extracted twice with 50 ml of ethyl acetate, and the organic phases were combined , and washed twice with 50 ml of water, the solvent was evaporated in a rotary evaporator to obtain a crude product. The crude product was recrystallized with methanol and decolorized with activated carbon to obtain pure 4...

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Abstract

The invention provides a synthetic method of a cyano-biphenyl type liquid crystal material, which is characterized in that a Grignard reagent prepared from 4'-alkyl (or alkoxy)-4-bromobenzene (or biphenyl) generates coupling reaction with 4-bromoxynil in a tetrahydrofuran solvent at a room temperature under the existence of catalyst palladium acetate, ligand triphenylphosphine and cocatalyst zinc bromide. After reaction liquid is cooled and is added with diluted hydrochloric acid for layering, a water phase is extracted by ethyl acetate; and after being washed and solvent-evaporated, a collected organic phase is recrystallized to obtain a pure product. The synthetic method has the beneficial effects that as the synthetic reaction is carried out at a room temperature without extremely-low temperature condition, the equipment investment and the production cost are reduced; and the operation is simple, a used raw material is low in cost, is easily obtained and is simple to treat after reaction, and after the product is simply recrystallized and purified, the yield reaches above 70 percent, therefore, the synthetic method is a practical and feasible synthetic route for the large-scale industrial production of the cyano-biphenyl type liquid crystal material.

Description

technical field [0001] The invention belongs to the field of liquid crystal materials, in particular to a method for synthesizing cyanobiphenyl type liquid crystal materials. Background technique [0002] Liquid crystal materials (LCD for short) are a new type of high-performance special material developed in the 1970s. The mesophase state of , is an orientation-ordered fluid (Gray, G. W.; Harrisorl, K. J.; Nash, J. A. J. Chem. Soc., Chem. Commun. 1974, 431-432.). It not only has the fluidity of liquid, but also has the characteristics of anisotropy such as birefringence of crystal. Because of its special physical, chemical, and optical properties, it has been widely used in electronic watches, electronic calculators, and computer display screens in recent decades. Liquid crystals have gradually become an indispensable and important material in the optoelectronic display industry (Huang Ximin. New progress in display technology [J].Liquid crystal and display. 2000,15(1):l...

Claims

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Application Information

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IPC IPC(8): C07C253/30C07C255/54C07C255/50C09K19/12
Inventor 梁永民朱春晖凡明锦
Owner LANZHOU UNIVERSITY
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