反应详情

Five grams of 3,4-dibromo-6-nitroaniline were suspended in 200 ml. of anhydrous ethanol to which was added about 10 g. of Raney nickel. The hydrogenation mixture was placed in a low pressure hydrogenation apparatus at a hydrogen pressure of 55 psi. A rapid uptake of hydrogen occurred which ceased after about 25 minutes, at which time the deep yellow color originally present had been discharged indicating complete reduction of the nitro group to an amino group. The hydrogenation was continued for another half hour and the hydrogenation mixture was then worked up by filtering off the catalyst, washing the filtered catalyst, and stripping the volatile constituents from the filtrate. A yield of 4.1 g. of 4,5-dibromo-o-phenylenediamine was obtained.

1. waitThe hydrogenation was continued for another half hour
2. filtrationby filtering off the catalyst
3. washwashing the filtered catalyst