To a reflux apparatus add 130 mL of conc. cold sulfuric acid and then with stirring 68 g of sodium or potassium nitrate. To a separatory funnel add 31.4 g of o- and p-bromonitrobenzene. The addition must be slow and the temperature must not exceed 70°C. After addition heat the mixture with stirring at 85°C for an hour. Then cool the solution down with stirring and filter, wash with 200 mL of cold water. Place the powder into a beaker and add 200 mL of water, heat until the crude product becomes molten and cool down with stirring then filter and wash with water. Recrystallize in 100 mL of hot methanol.
The mixture while the addition
The mixture after addition and heating
The crude product solidified after cooling down to room temp
Recrystallization in hot methanol
The pure recrystallized product