Divinyl liquid crystal compound and preparation method thereof

Abstract

The invention relates to a divinyl liquid crystal compound and a preparation method thereof. A structural formula of the divinyl liquid crystal compound is expressed as the following general formula I, wherein R1 represents hydrogen, C1-8 straight-chain alkyl or C2-8 straight-chain vinyl; R2 represents hydrogen or C1-8 straight-chain alkyl; A represents benzene ring or 1,4-cyclohexane ring; and nis equal to 1 to 2 and m is equal to 0 to 2. The preparation method for the divinyl liquid crystal compound comprises that: corresponding phosphine salt and aldehyde undergo wittig reaction in the presence of alkali to generate cis and trans mixed alkene, and then the cis and trans mixed alkene is transformed into trans alkene. The invention has the advantages that: a series of negative liquid crystals are developed, have wider liquid crystal phase change range, good chemical stability and excellent use value and can reduce the freezing point and improve the clearing point when added into mixed liquid crystal and increase the absolute value of a negative dielectric constant.

Description

technical field The invention relates to a diethylene liquid crystal compound and a preparation method thereof, belonging to the field of liquid crystal materials. Background technique Liquid crystal displays are widely used in laptop computers, televisions, various household appliances display screens, industrial display instruments, automotive instruments, and desktop monitors due to their low energy consumption, long life, small impact on the human body and the environment, and easy portability. , aerospace and other fields. Common liquid crystal working modes are: TN (twisted nematic), STN (super twisted nematic), TFT (thin film transistor), GH (guest-host) and so on. Among them, TFT uses a thin film transistor array to directly drive liquid crystal molecules, which eliminates the effect of cross distortion, and thus has a large display information capacity. With the use of low-viscosity liquid crystal materials, the response speed is greatly improved, which can meet t...

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Problems solved by technology

Although the patent DE10157674 contains vinyl liquid crystals in the structural formula, it does not specifically disclose the synthesis of the compounds listed in this article.

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