(Salicylic Acid 0.5%, Active Ingredient of Clean & Clear)
Salicylic acid is a white powder or needle shaped crystals with sweetish
taste;soluble in acetone, ether,and alcohol. boiling water, benzene
and turpentine. It is sparingly soluble in chloroform benzene, slightly
soluble in water; it melts at 158C. It is prepared commercially by
sodium salicylate which is made from sodium phenolate with carbon dioxide
under heating and pressure.
C7H6O3
It contains both a hydroxyl and a carboxyl group, which react with either an acid or alcohol. The carboxyl group forms esters with alcohols; e.g. methyl salicylate is formed with methanol, which is used in food flavorings and preservatives; menthyl salicylate is formed with methanol, which is used in tanning lotions; phenyl salicylate (called salol) is formed with phenol, which is used as an antiseptic and antipyretic agent.
The hydroxyl group reacts with acetic acid to form acetylsalicylic acid (aspirin). Salicylic acid is important for the preparation of other pharmaceutical products, dyes, flavors, and preservatives. The sodium salt (salicylate), a shiny white powder, is used for antiseptics preparations and as a preservative.
