A suspension of
sodium amide (0.275 mole) (Note
1) in
liquid ammonia is prepared in the following manner in a
1-l. three-necked flask equipped with an
air condenser (Note
2), a sealed
mechanical stirrer, and a
dropping funnel. Commercial anhydrous
liquid ammonia (600 ml.) is introduced by pouring from an
Erlenmeyer flask (Note
3). To the stirred liquid
ammonia is added a small piece of
sodium. After the appearance of a permanent blue color (Note
4) a few crystals of
ferric nitrate hydrate (ca. 0.1 g.) are added, followed by small pieces of freshly cut
sodium (Note
5) until 6.32 g. (0.275 g. atom) has been added. After all the
sodium is converted to the amide (Note
6),
42.0 g. (0.250 mole) of diphenylmethane (Note
7) in
20 ml. of anhydrous ether is added (Note
8). The deep red suspension is stirred for 15 minutes.
n-Butyl bromide (37.6 g., 0.274 mole) (Note
7) in
20 ml. of anhydrous ether is then added dropwise with stirring. The
ammonia is allowed to evaporate (Note
9) from the resulting gray suspension. Water (100 ml.) is added carefully (Note
10), then
100 ml. of ether. The ethereal layer is separated, and the aqueous layer is extracted with two further
100-ml. portions of ether. The combined ethereal extracts are dried over
Drierite and filtered, and the solvent is removed. The resulting liquid (
54.5 g.,
97%) is essentially pure
1,1-diphenylpentane (Note
11) and (Note
12) The liquid is distilled with the use of a
Claisen distillation head without a
fractionating column. The fraction, b.p.
138–139° (1.5 mm.),
n26D 1.5501, weighs
51.6 g. (
92%) (Note
13).