Galvinoxyl/K_3Fe(CN)_6/KOH复合体系相转移催化合成对称取代偶氮苯

Oxidation of Aromatic Amines to Symmetrical Substituted Azobenzenes under Phase - Transfer Catalysis with Galvinoxyl/K_3Fe(CN)_6/KOH System

用Galvinoxyl自由基为催化剂,芳胺类化合物在饱和铁氰化钾的氢氧化钾溶液和二氯甲烷的两相转移催化下合成了18个对称取代偶氮苯,提供了一个快速、方便、高效的制备偶氮苯类化合物的新方法,讨论了Hammett取代基常数与反应速度的关系,同时也讨论了取代基效应对产率的影响,并对反应机理也做了合理的解释.

Using Galvinoxyl and potassium ferricyanide as catalyst, the oxidation of aromatic amines to symmetrical azobenzenes in a mixture of aqueous potassium hydroxide and dichloromethane is described for the first time in this paper. Close corelation between the rates and Hammett substituent constants is observed. The yields of products were also affected by substituents. The present work offers an efficient and rapid method for preparing azobenzenes. A possible mechanism is suggested as well.