1. An improved procedure for preparation of
allyl cyanide (3-butenenitrile) is as follows: In a dry (washed with absolute
ethanol and absolute
ether)
500-ml. three-necked flask, equipped with a sealed mechanical stirrer and a 90-cm. bulb condenser set vertically and protected by a calcium chloride tube, are placed
85 g. of dry cuprous cyanide (commercial, or prepared as previously described;
1 dried for 72 hours in an
oven at 110° just before use),
0.25 g. of potassium iodide, and
72.5 g. of allyl chloride (dried over
calcium chloride and freshly distilled; b.p.
45–47°). The stirrer is started, and the mixture is heated on a
water bath. After about 6 hours the reaction is substantially complete, as indicated by cessation of the refluxing; heating is continued for 1 hour beyond this point. With larger runs it may be necessary to moderate the reaction by removing the water bath when vigorous refluxing sets in. This usually occurs about 3–5 hours after heating is started. Runs of the size described do not require any special attention. The water bath is replaced by an
oil bath, the condenser is set downward for distillation, and stirring is continued while the
allyl cyanide is distilled into a
100-ml. distilling flask. Near the end of the distillation it may be necessary to discontinue stirring, and it is advisable to reduce the pressure somewhat to aid in the removal of the last portion of the product. The distillate is redistilled, and
50–53 g. (
79–84%) of
allyl cyanide boiling at
116–122° is collected. (Private communication from Curtis W. Smith and H. R. Snyder; checked by W. E. Bachmann and G. Dana Johnson.)
5. A
Dry Ice trap, inserted between the oil pump and the apparatus, condenses
5–10 g. of unchanged allyl cyanide. The yield of crude acid, after allowing for the recovered nitrile, is 62–72%.