4-烷基苯甲酸液晶中间体的合成及其液晶性能

The synthesis and properties of liquid crystal intermediates 4-alkyl benzoic acids

以苯、C2～C5的酰氯为原料,经傅-克酰基化、黄鸣龙还原、乙酰化反应和溴仿反应合成了4个端基为C2～C5的单环芳香酸。以气相色谱-质谱联用仪、红外光谱仪、紫外光谱仪对芳香酸结构进行了表征。利用差热扫描量热仪、热台偏光显微镜对化合物的液晶性能进行了测试。结果表明,对于分子的长径比小于4的这类化合物,通过分子间氢键缔合的形式,亦可产生液晶相;其液晶相温度范围为9～20℃,呈现出向列相纹影织构。

4 Single ring aromatic acids with terminal alkyls from C2 to C5 were synthesized with benzene and acyl chloride from C2 to C5 as raw materials by reactions of F-C, Huang Minglong, acylation,reduction of acetylation and bromoform. Their structures were characterized by gas chromatography-mass spectrome- try,infrared spectrophotometer and UV spectrophotometer. Their property of liquid crystal was also detec- ted by using differential scanning calorimeter and thermal platform polarized microscope. The results showed molecules whose ratios of length to width were less than 4 can also form mesophases by hydrogen boding between double molecules. The temperature ranges of mesophase of the series of liquid crystals were hetween 9 ~ and 20 ~ showing a nematic schlieren textures