glycerol, glycerin, glycerine, or 1,2,3-propanetriol, CH₂OHCHOHCH₂OH, colorless, odorless, sweet-tasting, syrupy liquid. Glycerol is a trihydric alcohol. It melts at 17.8°C;, boils with decomposition at 290°C;, and is miscible with water and ethanol. It is hygroscopic; i.e., it absorbs water from the air; this property makes it valuable as a moistener in cosmetics. Glycerol is present in the form of its esters (glycerides) in all animal and vegetable fats and oils. It is obtained commercially as a byproduct when fats and oils are hydrolyzed to yield fatty acids or their metal salts (soaps). Glycerol is also synthesized on a commercial scale from propylene (obtained by cracking petroleum), since supplies of natural glycerol are inadequate. Glycerol can also be obtained during the fermentation of sugars if sodium bisulfite is added with the yeast. Glycerol is widely used as a solvent; as a sweetener; in the manufacture of dynamite, cosmetics, liquid soaps, candy, liqueurs, inks, and lubricants; to keep fabrics pliable; as a component of antifreeze mixtures; as a source of nutrients for fermentation cultures in the production of antibiotics; and in medicine. It has many other uses as well.

or glycerin

Clear, colourless, viscous, sweet-tasting liquid organic compound of the alcohol family, chemical formula HOCH₂CHOHCH₂OH. With three hydroxyl (singlehorzbondOH) groups, it can form three types of esters (monoglycerides, diglycerides, and triglycerides). Mono- and diglycerides are common food additives. Fats and oils are triglycerides; their processing into soap was the chief source of glycerol until the mid-20th century, when industrial synthesis took over. Glycerol has thousands of uses, including as an emulsifier, softening agent, plasticizer, and stabilizer in baked goods, ice cream, and tobacco; in skin lotions, mouthwashes, and cough medicines; as a protective medium for freezing red blood cells, sperm, corneas, and other tissues; in printing inks and in the gums and resins in paints and coatings; in antifreeze mixtures; as a nutrient in fermentation; and as a raw material for nitroglycerin.

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