As glycols or glycols that are dialcohols (dihydric alcohols referred to) extending from the ethylene derived (so-called 1,2-diols or vicinal diols). Examples are ethylene glycol and propylene glycol . In addition, derivatives of ethylene glycol, such as. B. methyl glycol (ethylene glycol monomethyl ether) and other diols whose hydroxyl groups are not arranged vicinally, such as trimethylene glycol or neopentyl glycol , referred to as glycols. Also α, ω-diols, which are formed by the condensation of ethylene glycol, such asDiethylene glycol , triethylene glycol or polyethylene glycol are referred to as glycols.
Properties and use
Glycols are often found in coolants , antifreeze and de-icers , as the freezing point of −10 to −15 ° C is below that of water. In conjunction with water, the freezing point is significantly lower and can reach -55 ° C with the right mixture. Glycol-containing fluids are also used as brake fluids . Propylene glycol-water mixtures are used as so-called smoke fluids for smoke machines in discos. Propylene glycol is also a component of liquids for e-cigarettes . In industry, they are mainly used as solvents and additives for varnishes, paints and cleaning agents. Triglycol is used in offshore oil production to dehumidify. It also has the effect of drying room air ( hygroscopic ). Glycols can also be found in various toothpastes.
A peculiarity of glycols ensured that glycol became the word of the year in 1985 after the glycol wine scandal . Because of the sweet aftertaste ( ancient Greek γλυκύς glykýs "sweet"), various wine producers used diethylene glycol to "refine" their wines forbidden. In doing so, they endangered the health of their consumers, because diethylene glycol can damage their health. The lethal dose is around 1.4 ml per kg of body weight. Diethylene glycol itself causes noise-like conditions similar to ethanol . Furthermore, it is metabolized in the body to various oxidation products such as glycolic acid and, to a lesser extent, to oxalic acid. These substances are neurotoxic and nephrotoxic ; the latter property can lead to kidney failure.