| 摘要 |
NEW MATERIAL:3-Fluoro-4-cyano-1-[trans-4-(trans-4-substituted-cyclohexyl)- cyhexyl]benzene of formula I (R is H or 1-15C alkyl or alkoxy). EXAMPLE:3-Fluoro-4-cyano-1-[ trans-4-( trans-4-propylcyclohexyl )cyclohexyl ]benzene. USE:A substance for liquid crystal display element. It has high positive dielectric anisotropy, and nevertheless, relatively low viscosity. It is stable to heat, light, air, and moisture, and exhibits liquid crystal phase over a wide temperature range. PREPARATION:The compound of formula I can be prepared by (1) reacting the compound of formula II with acetyl chloride in carbon disulfide in the presence of aluminum chloride, (2) reacting with sodium hypobromite, (3) reacting the reaction product with thionyl chloride, (4) reacting the resultant acid chloride compound with ammonia water, and (5) dehydrating the reaction product.
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