3. Other Methods of Preparation
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.
5 Jahresb. 1863, 422.
6 Ann. 159, 7 (1871); Ber. 8, 760 (1875).
[7] Ber. 8, 760 (1875).
[8] Ann. 107, 233 (1858).