LIQUID CRYSTAL HALOGEN COMPOUNDS, PROCESS FOR THEIR PREPARATION, DIELECTRIC AND DECTROOPTICAL DISPLAY ELEMENT CONTAINING THEM

摘要

Liquid-crystalline halogen compounds of the formula wherein the ring A is 1,4-phenylene or trans-1,4-cyclohexylene; R1 is alkyl or alkoxy each of 1 to 12 carbon atoms or, when A is 1,4-phenylene, is also cyano; R2 is alkyl or alkoxy each of 1 to 12 carbon atoms or, when A is 1,4-cyclohexylene, is also chlorine or bromine; and X is fluorine, chlorine or hydrogen; with the proviso that at least one of the substituents R2 and X is a halogen atom are valuable components in liquid-crystalline dielectrics.