| 摘要 |
NEW MATERIAL:The compound of formula I [Z is group of formula II, formula III(R is 3-8C straight-chain alkyl or alkoxy), formula IV or formula V (R is 3-8C straight-chain alkyl)]. EXAMPLE:4-n-Butylbenzoic acid 3'-chloro-4'-fluorophenyl ester. USE:A liquid crystal composition having high positive dielectric anisotropy, lowered driving voltage and improved response characteristics. PREPARATION:The compound of formula I can be prepared by (1) reacting the carboxylic acid of formula VI with a halogenation agent (e.g. thionyl chloride), and (2) reacting the resultant carboxylic acid halide of formula VII (X is halogen) with 3-chloro-4-fluorophenol of formula VIII in an inert solvent (e.g. diethyl ether). Preferably, a basic substance (e.g. pyridine) is added to the inert solvent to remove the isolated hydrogen halide from the reaction system.
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