In a
2-l. round-bottomed flask with a
reflux condenser,
104 g. (0.5 mole) of anthraquinone, m.p.
276–280° (corr.), is mixed with
100 g. (0.86 atom) of granulated tin, and
750 cc. of glacial acetic acid is added. The contents of the flask are heated to boiling, and in the course of two hours,
298 g. (250 cc., 8.2 moles) of c.p. hydrochloric acid (sp. gr. 1.19) is added in 10-cc. portions to the boiling mixture. At the end of this time all the
anthraquinone should have gone into solution; if not, more
tin and
hydrochloric acid are added.
The liquid is filtered with suction through a
Gooch crucible with a fixed porous plate (Note
1), and 100 cc. of water is added. The
anthrone crystallizes when the solution is cooled to about 10°. The crystals are filtered with suction on a
Büchner funnel and washed with water. After drying on a porous plate the melting point of the material is about
153°. The yield is
80 g. (
82.5 per cent of the theoretical amount). On recrystallization from a 3:1 mixture (Note
2) of
benzene and petroleum ether about
60 g. of
anthrone melting at
154–155° (corr.) is obtained (
62 per cent of the theoretical amount).