Terminal vinyl polyfluorinated diaryl acetylene liquid crystal compound and preparation method thereof

A technology of polyfluorinated diaryl and polyfluorodiaryl groups, which is applied in the field of polyfluorodiarylacetylene-terminated liquid crystal compounds and their preparation, can solve the problem of high melting point and enthalpy of fusion, large dielectric anisotropy, Affecting the liquid crystal phase transition range and response speed, etc., to achieve the effect of simple operation, high product yield and purity

Active Publication Date: 2016-04-06
XIAN CAIJING OPTO ELECTRICAL SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The compounds currently developed and researched have large dielectric anisotropy (-5~-6), but high melting point and enthalpy of fusion, and relatively high viscosity. It is necessary to add a liquid crystal mixture with a low melting point and low viscosity to reduce the mixing. crystal melting point and viscosity
This will lead to a decrease in the liquid crystal clearing point and birefringence, which will affect the phase transition range and response speed of the liquid crystal.

Method used

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  • Terminal vinyl polyfluorinated diaryl acetylene liquid crystal compound and preparation method thereof
  • Terminal vinyl polyfluorinated diaryl acetylene liquid crystal compound and preparation method thereof
  • Terminal vinyl polyfluorinated diaryl acetylene liquid crystal compound and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0029] Take the preparation of 4-ethylphenyl-4'-allyloxy-2,3,2',3'-tetrafluorotoluene as an example, wherein R is a straight-chain C2 alkyl group, and the values ​​of m and n are The values ​​are all 0, and the value of x is 0, and the raw materials used and their preparation methods are as follows:

[0030] Step 1: Synthesis of 4-ethylphenylboronic acid: under nitrogen protection, add 4-ethylbromobenzene 55.2g (0.30mol) to a 500mL three-necked flask equipped with a constant pressure dropping funnel, a thermometer and a magnetic stirrer, Inject 250 mL of dry tetrahydrofuran into the reaction flask and 144 mL (2.5 mol / L, 0.36 mol) of n-butyllithium solution into the constant pressure funnel respectively via a syringe. Cool the reaction system to -78°C with liquid nitrogen, start to add n-butyllithium solution dropwise, continue to react at this temperature for 1h after the dropwise addition, add 69.0g (0.30mol) tri-n-butyl borate dropwise, and control The dropping speed is suc...

Embodiment 2

[0044] Take the preparation of 4-propylphenyl-4'-allyloxy-2,3,2',3'-tetrafluorobenzil as an example, wherein R is a straight-chain C3 alkyl group, and the values ​​of m and n are The values ​​are all 0, and the value of x is 0, and the raw materials used and their preparation methods are as follows:

[0045] In Example 1, the 4-ethyl bromobenzene used was replaced with equimolar 4-propyl bromobenzene, and the other steps were the same as in the corresponding examples to prepare 4-propylphenyl-4'-allyloxy- 2,3,2',3'-Tetrafluorotoluene.

[0046] The phase transition temperature of 4-propylphenyl-4'-allyloxy-2,3,2',3'-tetrafluorobenzil is: Cr62.9N191.7I.

Embodiment 3

[0048] Take the preparation of 4-butylphenyl-4'-allyloxy-2,3,2',3'-tetrafluorotoluene as an example, wherein R is a C4 linear alkyl group, m and n are taken as The values ​​are all 0, and the value of x is 0, and the raw materials used and their preparation methods are as follows:

[0049] In Example 1, the 4-ethylbromobenzene used was replaced with equimolar 4-butylbromobenzene, and the other steps were the same as in the corresponding examples to prepare 4-butylphenyl-4'-allyloxy- 2,3,2',3'-Tetrafluorobenzil.

[0050] The phase transition temperature of 4-butylphenyl-4'-allyloxy-2,3,2',3'-tetrafluorobenzil is: Cr40.6N168.2I.

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Abstract

The invention relates to an alkene-terminated polyfluorinated diaryl acetylene liquid crystal compound and a synthesis method thereof. The compound is shown in the structural formula I as shown in the specification, wherein in the structural formula I, (F)m and (F)n both refer to fluorine atom substitutes; m and n refer to the substitute number of fluorine atoms, and the value thereof is 0-2; x refers to the number of connected methylene, and the value thereof is 0-3; and R refers to C1-C15 alkyls, C1-C15 alkenyls, C1-C15 alkoxy and C1-C15 enyloxy. According to the invention, because the compound is synthesized through adopting classic reactions such as nucleophilic substitution, coupling reaction, and the like, the operation is simple, and the yield and purity of products are high; and the compound has the advantages of large negative dielectric anisotropy, low melting point, wide liquid crystal phase interval, large double refraction, and the like, and can be applied to a dual-frequency liquid crystal display mode.

Description

technical field [0001] The invention belongs to the field of material technology, and in particular relates to a terminal vinyl polyfluorodiaryl acetylene liquid crystal compound and a preparation method thereof. Background technique [0002] Dual-frequency liquid crystals (DFLCs) can simultaneously reduce the response time T of the liquid crystal on and relaxation time T off , has a unique advantage in improving the response speed of liquid crystals, and has a good application prospect in large-screen TVs. The dual-frequency liquid crystal material is composed of a negative dielectric anisotropy compound as the main formula, and a positive dielectric anisotropy compound is added. The lateral polyfluorine-substituted terphenyl compound shows the advantages of large negative dielectric anisotropy and high birefringence, but its melting point is high and the phase transition interval is narrow, which is difficult to meet the requirements in dual-frequency liquid crystals. a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C43/225C07C41/16C09K19/18
Inventor 安忠维莫玲超陈新兵陈沛
Owner XIAN CAIJING OPTO ELECTRICAL SCI & TECH
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