含氟联苯酚酯类液晶材料的合成

Synthesis of Fluorinated Biphenol Ester Liquid Crystal Material

以含氟溴苯为原料,在N2保护下,经格氏反应,在-10℃条件下,生成含氟苯硼酸,然后以PdCl2为催化剂与对溴苯酚偶联,制得含氟联苯酚,通过与烷基苯甲酰氯的反应,制备了三环的含氟联苯酚酯类液晶,总收率大于30%,液相色谱测定其质量分数大于98%。目标化合物经IR、1H NMR、MS确认了分子结构。DSC分析表明,该类化合物有较高的清亮点(>209℃)和宽的介晶相温度范围(>98℃),用AM1方法,对其进行了几何结构优化,从微观结构讨论了其性质,结果表明,能与苯环共轭的含端位氰基的液晶材料的熔点和清亮点较高,这与实验结果一致。

Fluorinated phenylboronic acid was synthesized from fluorinated bromobenzene by Grignard reaction under nitrogen at - 10 ℃ and then coupling with p-bromophenol by PdCl2 to obtain fluorinated biphenol. Fluorinated biphenol ester liquid crystals were synthesized by esterification of fluorinated biphenol with alkyl benzoyl chloride. The total yield of objective products was higher than 30%. The mass fractions of the products by GC were over 98%. The structures of liquid crystal compounds were confirmed by IR, 1 HNMR and MS. The results of DSC show that these liquid crystal compounds exihibit high clear points（ 〉209 ℃ ） and a broad temperature range of mesomorphic phases（ 〉 98 ℃ ）. AM1 calculation has been performed to obtain molecular geometries of An. The calculation results indicated that liquid crystals with end group which can be conjugated with benzene had a higher melting point and clear points in accord with experiment.