4-溴-4'-丙基联苯的合成研究

Synthesis of 4-Bromo-4'-propylbiphenyl

联苯类液晶显示材料被认为是很有开发前景和实用价值的一类光电材料,4-溴-4'-丙基联苯是合成联苯类液晶显示材料重要的中间体。以4-丙基联苯为原料,采用直接溴代反应得到4-溴-4'-丙基联苯,并通过IR、NMR对其结构进行了表征。对影响反应的重要因素进行了考察和讨论。最佳工艺条件如下:n(4-丙基联苯):n(NBS)=1:0.99,反应时间3.0h,反应温度为55℃,NBS是分批加入。反应收率为76.6%,纯度为98.5%。采用的工艺路线合理,产品收率高。

The biphenyl liquid crystal display materials are confirmed as a series of photoelectric material with good development prospect and practical value.4-bromo-4'-propylbiphenyl is the important intermedium for the synthesis of biphenyl liquid crystal display materials.4-bromo-4'-propylbiphenyl is synthesized from 4-propylbiphenyl by direct bromination reaction.The structure of target compounds is characterized by IR and NMR.The major factors influencing the reaction are investigated and discussed.The optimal conditions have been obtained as follows:n(4-propyl-biphenyl):n(NBS)=1:0.99,the reaction time is 3.0 h,the reaction temperature is 55 ℃ and the stage addition is adopted.The yield is 76.6% with a purity of 98.5%.The process route adopted is reasonable with a high yield.