Org. Synth. 1928, 8, 4
Submitted by J. V. Supniewski and P. L. Salzberg.
Checked by Frank C. Whitmore, H. F. Herzog, and Gladys E. Woodward.
(A) Preparation of Cuprous Cyanide.—(Note 1)—In a 6-l. round-bottomed flask fitted with a stopper carrying a mechanical stirrer, a separatory funnel, and a gas exit tube leading to a good hood (Note 2), is placed a solution of 650 g. (2.6 moles) of crystallized copper sulfate in 4 l. of water. The flask is surrounded by an oil bath and heated to about 80°. The stirrer is started and a solution of 255 g. (5.2 moles) of sodium cyanide (Note 3) in 650 cc. of water is added from the separatory funnel over a period of about one-half hour. Then the mixture is boiled until no more cyanogen gas is evolved. This requires about five to ten minutes.
The cuprous cyanide, which begins to separate as a light tan precipitate as soon as any of the cyanide solution is added, is allowed to settle and the solution is decanted. The precipitate is filtered, then washed with water (1 l.) and finally with alcohol (500 cc.) and ether (300 cc.). After drying at 110° for about thirty-six hours, the product weighs 200–210 g. (85–90 per cent of the theoretical amount).
(B) Allyl Cyanide.—In a 1-l. round-bottomed flask fitted with a condenser (Note 4) and a mechanical stirrer are placed 220 g. (1.83 moles) of allyl bromide (Note 5) and 170 g. (1.9 moles) of dry cuprous cyanide (Note 6). The mixture is heated in a water bath and the stirrer rotated slowly by hand until the reaction starts (about fifteen to thirty minutes). When the reaction once begins, it becomes vigorous, and the heating bath must be replaced by a cooling mixture of ice and water in order to avoid loss of product through the condenser. After the vigorous reaction has subsided, the water bath is replaced, the mechanical stirrer is started and the mixture is heated until no more allyl bromide refluxes. This requires about one hour.
The condenser is then set for distillation and the allyl cyanide is distilled from the flask by heating it in an oil bath with stirring (Note 7) and (Note 8). Upon redistillation, the allyl cyanide is pure and boils at 116–121° with almost no loss. The yield is 98–103 g. (80–84 per cent of the theoretical amount).
Technical cuprous cyanide
dried at 110° gives as good results as the specially prepared substance.
evolved in this reaction should be led into a flue
with good suction draft or removed by a gas absorption trap (Fig. 7 on p. 97)
. It may be burned if a trap
is placed in the system to allow the moisture to condense.
The ordinary technical sodium cyanide
A very efficient condenser is needed as the mixture refluxes vigorously during the first part of the reaction. A condenser of the bulb
type about 90 cm. long is satisfactory. If a less efficient condenser is used, the upper end should be fitted with a tube leading into an empty flask to catch any material forced out.
The allyl bromide (p. 27)
should be dried over calcium chloride
, filtered and redistilled, the fraction boiling at 69–71° being used.
The cuprous cyanide
must be dry, as small amounts of moisture reduce the yield considerably (about 15 per cent). With some samples of technical cuprous cyanide
a larger amount must be used.
Toward the end of this distillation it is advisable to connect with the suction to remove the last of the allyl cyanide
from the solid residue in the flask.
The residue in the flask is very tarry. It is best removed by careful treatment with strong nitric acid
, then with water, and finally with hot alcohol
. If necessary, the treatment is repeated several times.
can be prepared from potassium cyanide
and allyl chloride
,1 allyl bromide2
and allyl iodide
The procedure described is essentially that of Bruylants,4
who has shown that the yields are much better when dry cuprous cyanide
is treated with allyl bromide
. Allyl cyanide
can also be prepared from allyl chloride
and cuprous cyanide
or from allyl alcohol
, cuprous cyanide
and hydrochloric acid
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
calcium chloride (10043-52-4)
hydrochloric acid (7647-01-0)
nitric acid (7697-37-2)
sodium cyanide (143-33-9)
Allyl bromide (106-95-6)
Allyl alcohol (107-18-6)
Cuprous Cyanide (544-92-3)
copper sulfate (7758-98-7)
potassium cyanide (151-50-8)
allyl chloride (107-05-1)
allyl iodide (556-56-9)
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