Quinone may be prepared by the oxidation of aniline with
dichromate or manganese dioxide and sulfuric acid.[1] This
is a more feasible commercial method than the one given.
However, the oxidation of hydroquinone is more rapid and
convenient and, hence is more desirable for use in the laboratory.
Various materials have been oxidized by chemical means to give quinone:
they are quinic-acid,[2] hydroquinone,[3] benzidine,[4]
_p_-phenylenediamine,[5] sulfanilic acid,[6] _p_-phenolsulfonic
acid,[7] arbutin,[8] aniline black,[9] and the leaves of various
plants.[10] Quinone is also formed by several other methods:
by the fermentation of fresh grass;[11] by the action of iodine
on the lead salt of hydroquinone;[1b] by the decomposition
of the compound, C6H4<.>2CrO2Cl with water;[2b] by the action of
sulfuric acid on phenol blue;[3b] by the electrochemical oxidation
of aniline,[4b] hydroquinone[5b] or benzene;[6b] by the catalytic
oxidation of benzene.[7b]
[1] Jahresb. 1863, 415; Ber. 10, 1934, 2005 (1877); 16, 687
(1883); 19, 1468 (1886); 20, 2283 (1887); 31, 1524 (1898); Ann.
200, 240 (1880); 215, 127 (1882).
[2] Ann. 27, 268 (1838).
[3] Ann. 51, 152 (1844) j Am. Chem. J. 14, 555 (1892).
[4] Jahresb. 1863, 415.