| 摘要 |
NEW MATERIAL:The trans-ethylene derivative compound of formula I (group of formula IVis trans-1,4-disubstituted cyclohexane ring; CH=CH is 1,2-disubstituted ethylene bond; R is 1-8C alkyl; R' is 1-5C alkyl). EXAMPLE:4-(trans-4'-n-Propyl-cyclohexyl)-1-(trans-3''-pentenyl)benzene. USE:An additive to lower the viscosity of a liquid crystal composition, and to remarkably improve its response speed. PREPARATION:The Grignard reagent obtained by the reaction of the compound of formula II with metallic Mg is made to react with the compound of formula III in the presence of CuI to obtain the objective compound of formula I . When one or more compounds of formula I are used as an additive of a liquid crystal composition in an amount of 1-50wt%, preferably 3-30wt%, a liquid crystal display element having extremely quick response and high contrast can be manufactured.
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