Sixty-two grams (61 ml., 0.67 mole) of aniline (Note
1) is mixed with
68.5 g. (0.66 mole) of benzonitrile in a
250-ml., wide-mouthed flask, and, during about 20 minutes,
89 g. (0.67 mole, calculated as AlCl3) of a freshly opened sample of powdered, anhydrous aluminum chloride is added in portions with thorough stirring (Note
2). The mixture is then heated at 200° for 30 minutes (Note
3), and, while still molten, is poured slowly into a thoroughly stirred mixture of
20 ml. of concentrated hydrochloric acid and 1.6 l. of water. After the addition of
20 g. of activated carbon, the suspension is stirred while being externally cooled in running water and is then filtered through a
kieselguhr filter (Note
4). The filtrate is poured in a steady stream into a stirred solution of
220 g. of sodium hydroxide in 1.2 l. of water. The flocculent precipitate is collected on alkali-resistant paper in a
12-cm. Büchner funnel with the aid of suction, washed with water (Note
5), broken up thoroughly, and air-dried at room temperature to constant weight. The yield of white product, m.p.
111–115°, is
90–96 g. (
69–74%). This material is sufficiently pure for most purposes. Recrystallization from
benzene (60 ml. per 10 g. of amidine) yields
56–74 g. of white powder; concentration of the mother liquors raises the total yield of
N-phenylbenzamidine to
69–86 g. (
53–66%), melting at
114–115.5°.