glycol(redirected from diol)
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glycol(glī`kōl), dihydric alcoholalcohol,
any of a class of organic compounds with the general formula R-OH, where R represents an alkyl group made up of carbon and hydrogen in various proportions and -OH represents one or more hydroxyl groups.
..... Click the link for more information. in which the two hydroxyl groups are bonded to different carbon atoms; the general formula for a glycol is (CH2)n(OH)2. The most important glycol is the simplest, ethylene glycol, or 1,2-ethanediol, CH2OHCH2OH, a slightly sweet-tasting, somewhat viscous liquid that is miscible with water. Because of its low volatility (b.p. 197°C;) and low corrosive activity, it is widely used in mixtures of automobile antifreezeantifreeze,
substance added to a solvent to lower its freezing point. The solution formed is called an antifreeze mixture. Antifreeze is typically added to water in the cooling system of an internal-combustion engine so that it may be cooled below the freezing point of pure
..... Click the link for more information. . Ethylene glycol can be esterified to form polyesters, e.g., DacronDacron
, trademark for a polyester fiber. Dacron is a condensation polymer obtained from ethylene glycol and terephthalic acid. Its properties include high tensile strength, high resistance to stretching, both wet and dry, and good resistance to degradation by chemical bleaches
..... Click the link for more information. , and can be nitrated to form an explosive used in mining. It is prepared commercially by oxidation of ethylene at high temperature over a silver oxide catalyst, followed by acid-catalyzed hydrolysishydrolysis
, chemical reaction of a compound with water, usually resulting in the formation of one or more new compounds. The most common hydrolysis occurs when a salt of a weak acid or weak base (or both) is dissolved in water.
..... Click the link for more information. of the ethylene oxide that is formed.
Cellosolves (e.g., methyl cellosolve, CH3OCH2CH2OH) are monoether derivatives of ethylene glycol. They are excellent solvents, having solvent properties of both ethers and alcohols; they have other uses as well. Polyethylene glycol (PEG) is used to thicken shampoo and cosmetics. It can also be attached to other molecules via a process called pegylation. When pegylated to medicinal drugs, it can alter their distribution in the body, metabolism, and excretion. Such alteration can lead to improved dosing intervals and may also have beneficial effects on safety and efficacy. Pegylation can also mask certain drugs, such as interferon, from the immune system, preventing their rejection.