对正癸氧基苯甲酸对苯酚基偶氮苯酯液晶的合成

Synthesis of O-decanoxylbenzoic O-phenyl Azobenzene Ester Liquid Crystal

目的通过重氮化反应、偶联反应、酯化反应和威廉姆逊反应合成新型液晶化合物对正癸基苯甲酸对苯酚基偶氮苯酯.方法对苯胺进行重氮化后与联苯酚发生偶合反应生成对苯酚基偶氮苯,将产物与对羟基苯甲酸在二环己基碳酰亚胺（DCC）为脱水剂,4-二甲氨基吡啶（DMAP）为催化剂的条件下发生酯化反应,得到的产物酯在碱性条件下与1-溴代正癸烷发生威廉姆逊反应生成对正癸氧基苯甲酸对苯酚基偶氮苯酯.结果实验表明：重氮化反应中,温度保持恒定的低温0~5℃是很重要的,否则易造成重氮化产率低的结果;偶联反应中,需控制pH=9才能有较好的收率;偶联产物需丙酮重结晶提纯后,再进行酯化反应,这样有利于提高产率,酯化反应先保持低温30 min后,再在室温反应24 h,这样可得较高产率.在最佳条件下,对正癸基苯甲酸对苯酚基偶氮苯酯的产率为85%.结论对正癸氧基苯甲酸对苯酚基偶氮苯酯的结构由1H NMR,MS和元素分析得以确证.

Objective O-decanoxylbenzoic o-phenyl azobenzene ester was synthesized by the diazotization reaction,coupling reaction,esterification reaction and Williamson reaction.Methods O-phenolylazobenzene was synthesized from the diazotization salt prepared from aniline and xenol by coupling reaction,and o-decanoxylbenzoic o-phenyl azobenzene ester was synthesized from the o-phenolylazobenzene and the p-hydroxybenzoic acid using dicyclohexylcarbodiimide as a dewater regent and 4-dimethylaminopyridine as a catalyst.And then the product ester acts with 1-bromodecane under Williamson reaction.Result The experiment shows： it is very important to keep temperature at 0~5 ℃ in the diazotization reaction,othenwise the rate of production will decline;the pH value of coupling reaction should be kept at 9;to get the higher rate,the product of coupling reaction should be purified by recrystallization,then esterification reaction should first keep 30 minutes at a low temperature,then 24 hours at the room temperature,thus getting a higher rate.Under the best reaction condition,the rate of o-decanoxylbenzoic o-phenyl azobenzene ester is 85%.Conclusion It is confirmed that the structures of o-phenolylazobenzene and o-decanoxylbenzoic o-phenyl azobenzene ester are characterized by 1H NMR,MS and Elemental analysis.