Description and uses.
Glycerin (glycerol) is a clear, colorless or almost colorless, odorless, syrupy, hygroscopic liquid. It is obtained as a byproduct of the soap and fatty acid (oleic acid or red oil and stearic acid) industries. Other sources are insignificant; glycerin can be produced by the fermentation of carbohydrates such as molasses, but when glycerin prices are low this process is not profitable. The chief commercial grades of crude glycerin are “soap lye” glycerin, a byproduct of the soap industry, containing about 80 percent glycerin, and “saponification” grade, a byproduct of the fatty acid industry, containing about 88 percent glycerin. Chemically pure grades contain about 95 percent and dynamite grades about 98.5 percent glycerin. Other grades include “30° yellow distilled” containing about 96 percent glycerin.
The uses of glycerin are extremely varied, the most important being in the manufacture of alkyd resins and ester gums; in the manufacture of nitroglycerin and dynamite; as a moistening, antiseptic, and sweetening agent in tobacco; in pharmaceutical and medicinal preparations; and in certain soft drinks, soaps, and inks.