液晶中间体对溴正戊苯的合成

Synthesis of Liquid Crystal Intermediate -1-Bromo-4-n-Pentyl Benzene

以溴苯、正戊酰氯和水合肼为原料 ,经Friedel Crafts酰基化反应和Wolff Kishn er 黄鸣龙还原反应合成对溴正戊苯。研究表明 ,酰基化反应较佳的条件是 ,n(正戊酰氯 )∶n(溴苯 )∶n(三氯化铝 ) =1∶2∶1 4,反应温度 30～ 35℃ ,反应时间 5h ;还原反应较佳的条件是 :n(对溴苯戊酮 )∶n(水合肼 )∶n(氢氧化钾 ) =1∶1 1∶0 2 ,反应温度 1 80～ 1 90℃ ,反应时间 3h。产品总产率约为 40 % ,纯度为 99 3%

The synthesis of 1-bromo-4-n-pentyl benzene was studied using bromobenzene, n-pentoyl chloride and hydrazine hydrate as starting materials through Friedel-Crafts reaction and Wolff-Kishner-Huang reduction. The optimum conditions of Friedel-Crafts reaction are as follows: n(n-pentoyl chloride)∶n(bromobenzene)∶n(aluminum chloride) =1∶2∶1.4, reaction time 5 h, reaction temperature 30～35 ℃.The optimum conditions of Wolff-Kishner-Huang reduction are as follows: n(1-bromo-4-n-pentanone benzene)∶n(hydrazine hydrate)∶n(potassium hydroxide)=1∶1.1∶0.2, reaction temperature 180～(190 ℃, )reaction time 3～4 h. Under above conditions, the final yield of 1-bromo-4-n-pentyl benzene was about 40%, the purity was 99.3%.