Most of these belong to the aromatic group of bodies, although one of them, antipyrin, belongs rather to the furfurol group. Carbolic acid has an antipyretic action, but on account of its poisonous properties it cannot be employed as an antipyretic. Salicylic acid has a strong antipyretic action, and is most commonly used in the form of its sodium salt, which is much more soluble than the acid itself.
The use of salicylic acid as a food preservative, was, however, condemned in the findings of the commission appointed by the government of the United States of America, in 1904.
Chromium oxychloride reacts violently on phenol, producing hydroquinone ether, O(C 6 H 4 OH)2; chromic acid gives phenoquinone, and potassium permanganate gives paradiphenol, oxalic acid, and some salicylic acid (R.
To remove these salicylic acid dissolved in flexible collodion is now generally employed.
Among such dyestuffs are chrysamine or flavophenine, obtained from salicylic acid and diazotized benzidine, and congo red obtained from sodium naphthionate and diazotized benzidine.
Sodium reduces salicylic acid in boiling amyl alcohol solution to n-pimelic acid (A.
In the remedy just mentioned the salicylic acid forms the basis; but sometimes chloride of zinc or lactic acid is added to it to make it act more quickly, and these are the adjuvants.
As an antiseptic salicylic acid is somewhat less powerful than carbolic acid, but its insolubility renders it unsuitable for general use.
Hydrobromic acid is often used to relieve or prevent the headache and singing in the ears that may follow the administration of quinine and of salicylic acid or salicylates.
All four mono-hydroxyxanthones are known, and are prepared by heating salicylic acid with either resorcin, pyrocatechin or hydroquinone; they are yellow crystalline solids, which act as dyestuffs.