A
1-l. three-necked flask is equipped with a
mercury-sealed stirrer, an
inlet tube, and a
reflux condenser which is connected through a
sodalime tube to a gas-absorption trap. The apparatus is dried in an
oven and assembled rapidly to exclude moisture; it is advisable to set up the apparatus in a
hood to vent
ammonia that may escape by accident. The flask is cooled in a
Dry Ice-trichloroethylene bath, and
200 ml. of anhydrous (refrigeration grade) ammonia is introduced through the inlet tube from an
ammonia cylinder which is either inverted or equipped with a
siphon tube. Just before the apparatus is assembled,
8.1 g. (0.35 gram atom) of sodium is cut, weighed, and kept under kerosene in a
small beaker. The Dry Ice bath is removed, the inlet tube is replaced by a
rubber stopper, and a crystal of hydrated
ferric nitrate (about 0.2 g.) is added. A small (about 5-mm.) cube of the
sodium is cut, blotted rapidly with filter paper, and added quickly to the liquid
ammonia. The solution is stirred until the blue color disappears, after which the remainder of the
sodium is added in narrow, thin strips about as rapidly as it can be cut and blotted, while the solution is stirred vigorously (Note
1). After the solution has turned from blue to gray, the flask is swirled by hand until the blue flecks of
sodium that have spattered onto the upper part of the flask are washed into the solution.
The flask is again cooled in the Dry Ice bath, and
41 g. (0.35 mole) of benzyl cyanide (Note
2) is added during about 10 minutes through a dry
dropping funnel. The Dry Ice bath is removed, and the clear solution is stirred for about 15 minutes, after which
200 ml. of dry sulfur-free toluene (Note
3) and
25 ml. of anhydrous ether are added dropwise through the funnel while the
ammonia evaporates. The solution is allowed to stand or is warmed in a
water bath until it comes to room temperature; the
ammonia may be vaporized at any rate that does not cause gas to escape through the mercury seal on the stirrer. The remainder of the
ammonia is removed by turning off the water in the reflux condenser, warming the flask in a hot water bath, and distilling most of the
ether (and
ammonia) through the reflux condenser.
A fresh drying tube is attached to the reflux condenser, the cooling water is turned on, and to the warm solution is added
65.2 g. (0.4 mole) of bromocyclohexane (Note
4) during approximately 20 minutes. The reaction is vigorous and may require cooling. Refluxing is continued by heating the mixture in an
oil bath for 2 hours. The reaction mixture is cooled and washed with 300 ml. of water. The aqueous layer is extracted with two
50-ml. portions of benzene, and the combined
benzene and
toluene solutions are washed with two 50-ml. portions of water and distilled from a
500-ml. modified Claisen flask under reduced pressure. The yield of
α-cyclohexylphenylacetonitrile boiling at
174–176°/13 mm. (Note
5) is
45–53 g. (
65–77%); the distillate solidifies to a crystalline mass which has a melting point of
50–53.5°. The nitrile can be recrystallized from commercial
pentane with approximately 15% loss; it then melts at
56–58°.