2-FLUOROBENZONITRILE DERIVATIVE

PURPOSE:To provide the subject compound, a new liquid crystal compound large in dielectric constant anisotropy, giving liquid crystal phase over a wide range of temperatures, also good in compatibility with other known liquid crystal compounds at low temperatures. CONSTITUTION:The objective compound of the formula (R is H or 1-10C straight chain or branched alkyl; X is H or F; -CH=CH- is in trans configuration), e.g. 4-{trans-4-[(E)-2-(trans-4-ethylcyclohexyl)vinyl]cyclohexyl}2-fluorobe nzonitrile. The compound of the formula can be obtained through 1-formyl-4-(3-fluoro or 3,5-difluoro-4-cyanophenyl)cyclohexane derived from staring materials, i.e., (1) a Grignard reagent prepared from 3-fluoro or 3,5-difluoro-bromobenzene and (2) 1,4-cyclohexanedionemonoethyleneketal. Addition of the compound of the present invention to a liquid crystal composition can significantly expand the temperature range for using the composition without raising its viscosity.