This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
An organic acid, in its commercial, more or less impure form, usually obtained from the more solid fats, chiefly tallow from the ox, Bos Taurus Linne; (class Mammalia; order Ruminantia).
Domesticated. By boiling with soda-lye, the Stearin is decomposed, Sodium Stearate being formed with the liberation of Glycerin. C3H5(C18H35O2)3+3NaOH =C3H5(OH)3+3NaC18H35O2. The soap is decomposed by heating with water and Sulphuric Acid, setting free the fatty acids which are removed and purified with hot Alcohol. On cooling, Stearic Acid will separate.
A hard, white, somewhat glossy solid, odorless and tasteless, and permanent in the air.
Insoluble in water; soluble in about 45 parts of Alcohol at 590 F.; 150 C, readily soluble in boiling Alcohol, and in Ether.
Uses of Stearic Acid.
Stearic acid is used in the manufacture of glycerin suppositories. In combination with zinc and copper, as stearates of those metals, unofficial preparations have been introduced and used with success in the treatment of various diseases of the skin and mucous membranes.