JIACOOH, are usually associated with stearic a in these sources. Animal fat contains the Ore of esters of all three acids in varying quanti 'es, depending upon the nature of the fat. Shea-bu er, a vegetable fat obtained in West Africa, c tains the glycerol esters of stearic and oleic cids only. When these fats are saponified then treated with a mineral acid, a mixture of the acids is produced. In the preparation of acids from fat, saponifica tion may be broleght about by the use of lime, superheated stea or sulphuric acid. The mixed acids are ,,F by first pressing between warm plat s in order to remove liquid oleic acid. The res idue is then dissolved in alcohol and poured in an alcoholic solution'of magnesium acetate; agnesium stearate pre cipitates first, yielding ree stearic acid when cation of hydrochloric treated with a hot so purified by crystal acid. The product may lization from alcohol.
have also A number of synthetic been developed for the prep aration of stearic acid. It may be obtained: (1) By heating oleic acid with hydrogen iodi and red phos the direct addi phorus at C.; (2) by or other un tion of hydrogen to oleic aci of nickel or saturated acids, in the presence other reduced metallic substance • the metals acting as catalysers. Accordin to United
g States patent stearic acid, tilted for toilet the manufacture pf candles or high-gr e fatty soaps, can be produced by hydrogenatin rely materials like tallow, in the presence of divided nickel, until the iodine number is duced to zero and the melting point is Tar_ to 62° C. The product is saponified and the acids extracted are purified. Stearic acid is a white crystalline solid with no taste or smell. It melts at 69.32° C. and boils at ordinary pres sures with partial decomposition at 360° C. The acid is insoluble in water, but will readily dissolve in boiling alcohol and ether. The potassium or sodium salts of stearic acid are the chief constituents of soft or hard soap. Commercial stearic acid, known as "stearin;' contains a large quantity of palmitic acid. In order to destroy its crystalline structure stearin is usually mixed with wax or paraffin; it is extensively used for the manufacture of can dles, stove polish, shoe polish and varnish. Pure stearic acid is used for the prepara tion of glycerin suppositories.