A suspension of
potassium amide (0.23 mole) in liquid
ammonia is prepared in a
1-l. three-necked flask equipped with an air condenser (without drying tube), a
ball-sealed mechanical stirrer, and a
dropping funnel. Commercial anhydrous liquid
ammonia (500 ml.) is introduced into the flask from a cylinder through an inlet tube. To the stirred
ammonia is added a small piece of
potassium metal. After the appearance of a blue color, a few crystals
(about 0.25 g.) of ferric nitrate hydrate are added, followed by small pieces of
potassium (Note 1) until 9.0 g. (0.23 g. atom) has been added. After all the
potassium has been converted to the amide (Note
2),
44.6 g. (0.23 mole) of diphenylacetonitrile (Note
3) is added and the resulting greenish-brown solution is stirred for 5 minutes. To this is added, over 10 minutes,
30.5 g. (0.24 mole) of benzyl chloride (Note
4) in
100 ml. of anhydrous ether. The orange solution is stirred for 1 hour, and the
ammonia is then evaporated on a
steam bath as
300 ml. of anhydrous ether is being added. To the
ether solution is added 300 ml. of water, whereupon the crude nitrile precipitates. The
ether is then removed by distillation and the crude nitrile is collected on a
Büchner funnel. The yield of crude, light-tan
α,α,β-triphenylpropionitrile is
64 g. (
98–99%). The nitrile is dissolved in
1.3 l. of hot ethanol, treated with
Norit, and filtered. The filtrate is held at room temperature overnight, and the product collected by filtration. A second crop is obtained by concentration of the mother liquor. The total yield of
α,α,β-triphenylpropionitrile, m.p.
126.5–127.5°, is
62.2–65.5 g. (
95–99% yield) (Note
5).