B.
m-Nitrobenzazide. In a
2-l. round-bottomed flask fitted with an
efficient mechanical stirrer is placed a solution of
78 g. (1.2 moles) of commercial sodium azide in 500 ml. of water (Note
3). The flask is surrounded by a
water bath kept at 20–25°. The stirrer is started, and over a period of about 1 hour a solution of
185.5 g. (1 mole) of m-nitrobenzoyl chloride in 300 ml. of acetone (previously dried over anhydrous
potassium carbonate) is added from a
dropping funnel.
m-Nitrobenzazide separates at once as a white precipitate. Stirring is continued for 30 minutes after the addition is complete; then 500 ml. of water is added and the reaction mixture stirred for an additional 30 minutes. The azide is separated on a
suction filter, washed with water, and dried in the air. The yield of crude product, m.p.
68°, is
189 g. (
98%) (Note
4). It may be recrystallized from a mixture of equal parts of
benzene and
ligroin (b.p.
100–140°), when the temperature is kept below 50° (Note
5). The product thus obtained consists of almost colorless crystals, m.p.
68–69° (Note
6), the recovery being
80–90% (Note
7).