colour. With ferric chloride it gives a violet coloration, and with
bromine water a white precipitate of tribrom-phenol.

When phenol is passed through a red-hot tube a complex decomposition
takes place, resulting in the formation of benzene, toluene,
naphthalene, &c. (J.G. Kramers, _Ann._, 1877, 189, p. 129). Chromium
oxychloride reacts violently on phenol, producing hydroquinone ether,
O(C6H4OH)2; chromic acid gives phenoquinone, and potassium
permanganate gives paradiphenol, oxalic acid, and some salicylic acid
(R. Henriques, _Ber._, 1888, 21, p. 1620). In alkaline solution,
potassium permanganate oxidizes it to inactive tartaric acid and
carbon dioxide (O. Doebner, _Ber._, 1891, 24, p. 1755). When distilled
over lead oxide, it forms diphenylene oxide, (C6H4)2O; and when
heated with oxalic acid and concentrated sulphuric acid, it forms
aurin, C19H14O3. It condenses with aceto-acetic ester, in the presence
of sulphuric acid, to [beta]-methyl coumarin (H. v. Pechmann and J.B.
Cohen, _Ber_., 1884, 17, p. 2188).

The hydrogen of the hydroxyl group in phenol can be replaced by
metals, by alkyl groups and by acid radicals. The metallic derivatives
(phenolates, phenates or carbolates) of the alkali metals are obtained
by dissolving phenol in a solution of a caustic alkali, in the absence
of air. Potassium phenolate, C6H5OK, crystallizes in fine needles, is
very hygroscopic and oxidizes rapidly on exposure. Other phenolates
may be obtained from potassium phenolate by precipitation. The alkyl
derivatives may be obtained by heating phenol with one molecular
proportion of a caustic alkali and of an alkyl iodide. They are
compounds which greatly resemble the mixed ethers of the aliphatic
series. They are not decomposed by boiling alkalis, but on heating
with hydriodic acid they split into their components. _Anisol_, phenyl
methyl ether, C6H5.O.CH3, is prepared either by the above method or by
the action of diazo-methane on phenol, C6H5OH+CH2N2 = N2+C6H5.O.CH3
(H. v. Pechmann, _Ber_., 1895, 28, p. 857); by distilling anisic acid
(para-methoxy benzoic acid) with baryta or by boiling phenyl diazonium
chloride with methyl alcohol. It is a colourless pleasant-smelling
liquid which boils at 154.3 deg. C. _Phenetol_, phenyl ethyl ether,
C6H5.O.C2H5, a liquid boiling at 172 deg. C., may be obtained by
similar methods. A. Hantzsch (_Ber._, 1901, 34, p. 3337) has shown