Reduction of Aromatic Nitro Compounds to Azoxy Compounds with Sodium Borohydride

The reduction of aromatic nitro compounds to corresponding azoxy compounds with sodium borohydride was catalyzed by BiO(OH)/actived carbon (AC), which was prepared by equivalent-volume impregnation. The influences of catalyst, sodium borohydride and sodium hydroxide amount were investigated with 10 mmol of nitrobenzene as substrate in methanol at room temperature. The suitable reaction conditions are as follows: 0.2 g of catalyst, 10 mmol of sodium borohydride and 0.1 g of sodium hydroxide. Under the conditions, the seven aromatic nitro compounds were reduced to corresponding azoxy compounds with 27%-90% yields. Moreover, slight deactivation was observed after nine cycles of the catalyst.