C10H10O2 = 162.08.
Safrol, C6H3C3H5(OOCH2), is the methylene ether of an allyl pyrocatechin. It is official in the U.S.P. It is the chief constituent of oil of sassafras, in which it exists to the extent of about 80 per cent.; it also occurs in other volatile oils, but commercially it is almost entirely got from essential oil of camphor by fractional distillation, collecting the fraction boiling at about 230°, and purifying by repeated refrigeration and crystallisation. Safrol occurs, at ordinary temperatures, as a colourless or faintly yellow liquid, having a characteristic and pleasant sassafras-like odour, a sharp taste, and a neutral reaction. It is optically inactive. On cooling to -20° it solidifies to a mass of crystals, which melt at 12°. It crystallises in well-defined, colourless, monoclinic crystals, having a specific gravity of 1.108; it boils at 233°, and may be heated to 280° without decomposition. Heated with alcoholic solution of potassium hydroxide isosafrol is formed, a body less toxic than safrol, and boiling at 246° to 248°. Both bodies dissolve in concentrated sulphuric acid with an intense red colouration. Safrol resists reduction with sodium, but isosafrol is readily reduced to dihydro-safrol, C10H12O2. On oxidation with chromic acid mixture, safrol yields piperonal, or heliotropin, and piperonylic acid, on which account it is of great commercial value. Careful oxidation with potassium permanganate first converts it into glycol and on further oxidation into homopiperonylic acid. When administered internally safrol is eliminated from the system principally as piperonylic acid.
Soluble in alcohol (about 1 in 1), 70 per cent. alcohol (about 1 in 30), in all proportions of ether or chloroform.
Action and Uses.—Safrol is employed in perfumery, and mixed with 2 or 3 parts of camphorated oil as a liniment in chronic rheumatism. It is given internally on sugar, in place of oil of sassafras.
Dose.—1 to 5 decimils (0.1 to 0.5 milliliters) (2 to 8 minims).