取代的对苯二酚制备及芳香聚酯的合成

Preparation of phenyl alkyl substituted 1,4-hydroquinones and synthesis of aromatic polyesters

以1,4-二甲氧基苯及芳香酰氯为原料,经付氏酰基化反应,生成相应的芳香酮,再经黄鸣龙改良还原、醚键的断裂两步合成了两个苯烷基取代的1,4-对苯二酚,其分别与对苯二甲酰氯进行熔融缩聚,得到两个芳香聚酯。采用显微熔点仪,红外光谱,元素分析,核磁共振,热重分析及示差扫描量热分析和偏光显微镜对产物的结构和性能进行了研究。结果表明,制得的聚酯均为热致型液晶,玻璃化温度分别为135℃,156℃,5%,热失重温度400℃以上,具有良好的热稳定性;均溶于对氯苯酚,在45℃形成稳定的溶液。加热时还部分地溶于二苯醚、四氯乙烷,溶解性有了显著地提高。

Two phenyl alkyl substituted hydroquinones were synthesized from 1,4-dimethoxybenzene by Friedel-Crafts reaction,Huang MinLong modification reduction and cleavage of ether bond.The two substituted 1,4-hydroquinones reacted with terephthaloyl dichloride respectively to obtain two aromatic polyesters by melt polycondensation.The structure and properties of products were studied by micro melting point instrument,IR,elemental analysis,NMR,TGA,DSC and polarizing microscope.The results showed that all the obtained polyester were thermotropic liquid crystal. The glass transition temperature of the products were 135 ℃, 156 ℃ respectively, The aromatic polyesters had good thermal stability and the 5 % weight loss temperature was above 400 ℃. They were soluble in chlorophenol and formed stable solution at 45 ℃ and partially soluble in diphenyl ether and tetrachloroethane. The solubility were significantly improved.