The solution is then acidified, and the phenols are'liberated and form an oily layer on the surface of the acid.
Nitro-phenols are readily obtained by the action of nitric acid on phenol.
The rationale of this treatment is not fully understood, but the action appears to consist in the separation or decomposition of the aromatic hydrocarbons, fatty and other acids, phenols, tarry bodies, &c., which lower the quality of the oil, the sulphuric acid removing some, while the caustic soda takes out the remainder, and neutralizes the acid which has been left in the oil.
The introduction of hydroxyl groups into the benzene nucleus gives rise to compounds generically named phenols, which, although resembling the aliphatic alcohols in their origin, differ from these substances in their increased chemical activity and acid nature.
The quinonoid structure of many coloured compounds has been proved experimentally, as, for example, by Hewitt for the benzene-azo-phenols, and Hantzsch for triaminotriphenyl methane and acridine derivatives; but, at the same time, many substances cannot be so explained.
CRESOLS or Methyl Phenols, C 7 H 8 0 or C 6 H 4 CH3.OH.
Tafel, Ber., 1886, 19, p. 1924), by distilling the amido-acids with lime, by heating phenols with zinc chloride ammonia (V.
- The'quinoles are a series of compounds of the type R >(=)=O obtained by the oxidation of para-alkylated phenols HO /?_ ?
They are crystalline solids which are readily converted into para-alkylated phenols by reducing agents.
The reaction of formaldehyde on phenols: 0.
The hydroxyl group is more reactive than in the phenols, the naphthols being converted into naphthylamines by the action of ammonia, and forming ethers and esters much more readily.
It differs from the simple ketenes in that it is apparently unacted upon by phenols and alcohols.
Many ortho and, para-compounds of the aromatic series (for example, the brom-phenols, benzene para-disulphonic acid) also yield resorcin on fusion with caustic potash.
By the reduction of nitro-phenols, the corresponding aminophenols are obtained, and of these, the metaand para-derivatives are the most important.
The phenols more closely resemble the tertiary alcohols, since the hydroxyl group is linked to.