2，2′-二氯氢化偶氮苯重排生成3，3′-二氯联苯胺的研究

采用Pd／C催化剂催化邻硝基氯苯加氢，制得2，2′-二氯氢化偶氮苯（DHB），再经过重排反应得到3，3′-二氯联苯胺（DCB）。研究了反应温度、硫酸质量分数和用量、反应时间等因素对重排反应的影响规律，确定了最佳重排反应条件，即反应温度0．5℃、硫酸质量分数50％、硫酸与DHB的摩尔比7：1、反应时间4h。在最佳条件下，产物3，3′-二氯联苯胺盐酸盐的收率为80％．83％，总氨基值大于95．0％。

Synthesis of 3,3′- Dichlorobenzidine by Rearrangement of 2,2′ - Dichlorohydrazobenzene

3,3′ - Dichlorobenzidine （DCB） was synthesized by rearrangement of 2,2′ - diehlorohydrazobenzene （DHB） which was obtained by catalytic hydrogenation of 2 - nitrochlorobenzene using Pd/C as catalyst. The effects of reaction parameters such as reaction temperature, mass fraction and amounts of sulfur acid, and reaction time on the rearranging reaction were examined. The optimum rearranging reaction conditions were determined as follows： reaction temperature 0 - 5 ℃, mass fraction of sulfur acid 50%, molar ratio of sulfur acid to DHB 7 ： 1, reaction time 4 h. The yield of DCB was 80% - 83% and the amino group value of the product was more than 95.0% under above conditions.