8-[4′-丙氧基(1,1-联苯)-氧]-辛酸的合成与表征

Synthesis and characterization of 8-[4′-propoxy (1,1-biphenyl)-yloxy]-octanoic acid

以联苯二酚为原料经2步反应合成了8-[4′-丙氧基(1,1-联苯)-氧]-辛酸,并对影响产率的因素进行了探讨;通过红外光谱和核磁共振谱表征了8-[4′-丙氧基(1,1-联苯)-氧]-辛酸的化学结构,并用差示扫描量热法和热台偏光显微镜表征了其热致液晶性质。结果表明,第1步合成4′-丙氧基-4-羟基联苯的适宜条件为:n(联苯二酚)∶n(溴代正丙烷)∶n(碱)=1∶1.2∶1,碘化钾用量为4.5%(以联苯二酚质量为基准),加热回流8h;第2步制得8-[4′-丙氧基(1,1-联苯)-氧]-辛酸的适宜条件为;n(碳酸钾)∶n(8-溴辛酸乙酯)∶n(4′-丙氧基-4-羟基联苯)=2∶1.5∶1,相转移剂四丁基溴化铵用量为10%(以4′-丙氧基-4-羟基联苯质量为基准),加热回流24h,将产物在甲醇中水解制得,产率40%,纯度可达94.9%。

8-[4＇-propoxy（1, 1-biphenyl）-yloxy]-octanoic acid has been synthesized in two steps from 4, 4＇-dihydroxybiphenyl and the factors influencing the yield studied. The optimal reaction conditions were found to be as follows： in the first step, with a molar ratio n （4, 4＇-dihydroxybiphenyl）： n （1-bromopropane）： n （alkali） of 1： 1.2 ： 1, and the weight of potassium iodide being 4.5 % of that of 4, 4＇-dihydroxybiphenyl, under reflux for 8 hours, 4-propoxy-4＇-hydroxybiphenyl was obtained; in the second step, with a molar ratio n （potassium carbonate） ： n （8-bromooctanoic acid ethyl ester ） ： n （4-propoxy-4＇-hydroxy） biphenyl of 2 ： 1.5 ： 1, and with the dosage of phase transfer agent （tetrabutylammonium bromide） being 10 % of that of 4-propoxy-4＇-hydroxybiphenyl, refluxing for 24 hours, followed by hydrolysis in methanol, afforded 8-[4＇-propoxy （1, 1-biphenyl）-yloxy]-octanoic acid in a yield of 40 % with a purity of 94.9 %. The chemical structure of 8-[4＇-propoxy （1, 1-biphenyl）- yloxy]-octanoic acid was confirmed by FTIR, and 1H and 13C NMR spectroscopy. The phase transition and liquid crystalline behavior of 8-[ 4＇-propoxy （1, 1-biphenyl）-yloxy]-octanoic acid were characterized by differential scanning calorimetry （DSC） and polarizing microscopy （POM）. The experimental results indicated that 8-[4＇- propoxy （1, 1-biphenyl）-yloxy]-octanoic acid is a thermotropic liquid crystal.