Organic Syntheses, Coll. Vol. 3, p.710 (1955); Vol. 22, p.96 (1942).
In a 1-l. three-necked flask fitted with a stirrer, a thermometer, and a dropping funnel
are placed 300 ml. of water and 55.5 ml. of concentrated hydrochloric acid
. The flask is surrounded by an ice-salt bath
, the stirrer is started, and 33.5 g. (0.31 mole) of phenylhydrazine (Note 1)
is added dropwise (5–10 minutes is required). Phenylhydrazine hydrochloride
separates as fine white plates. Stirring is continued, and, after the temperature has fallen to 0°, 100 ml. of ether
is added, after which a previously prepared solution of 25 g. of technical sodium nitrite
in 30 ml. of water is added from the dropping funnel at such a rate that the temperature never
rises above 5°. This requires 25–30 minutes.
The reaction mixture is subjected to steam distillation until about 400 ml. of distillate is obtained. The ether
layer is removed from the distillate, and the aqueous layer is extracted once with 25 ml. of ether
. The combined ethereal solutions are dried over 10 g. of anhydrous calcium chloride
. The dried solution is placed in a 200-ml. ordinary Claisen flask
arranged for vacuum distillation. The flask must be surrounded by a cylindrical wire screen, and a laminated glass screen must be interposed between the operator and the apparatus (Note 2)
. The flask is immersed in a water bath
at 25–30°, and the ether
is removed under reduced pressure. Then the temperature of the water bath is raised to 60–65°, and the product is distilled under reduced pressure. Phenyl azide
boils at 49–50° at 5 mm. (Note 3)
. A yield of 24–25 g.
) of the pungent, pale yellow, oily azide is obtained (Note 4)
The phenylhydrazine used was the best grade supplied by the Eastman Kodak Company
. With technical material, or a preparation that was appreciably discolored, the yield was much less (45–50%
), and a considerable amount of tar was formed.
Care must be exercised during the distillation. Phenyl azide
explodes when heated at ordinary pressure, and occasionally at lower pressures. The water-bath temperature should never be permitted to rise above 80° at any time.
boils at 66–68°/21 mm.
with a bath temperature of 70–75°. It is advisable to use as low a bath temperature as possible and a pressure of 5 mm. or less. The checkers have used these directions repeatedly without any explosions.
The product should be stored in a brown glass bottle
. It will keep for a month in a cool, dark place.
This preparation is referenced from:
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