IAQUK Resources - Ethylene Glycol
Source of pollution
Ethylene Glycol is produced from Ethylene (Ethene), via the intermediate Ethylene Oxide (formula C2H4O). Ethylene Oxide reacts with water to produce Ethylene Glycol.
This reaction can be catalyzed by either acids or bases, or can occur at neutral pH under elevated temperatures. The highest yields of Ethylene Glycol occur at acidic or neutral pH with a large excess of water. Under these conditions, Ethylene Glycol yields of 90% can be achieved.
Approximately 60% of Ethylene Glycol is consumed for antifreeze, and the remainder is mainly used as a precursor to polymers.
Coolant and heat transfer agent
The major use of Ethylene Glycol is as a medium for convective heat transfer in, for example, vehicles and liquid cooled computers. Ethylene Glycol is also commonly used in chilled water air conditioning systems that place either the chiller or air handlers outside, or systems that must cool below the freezing temperature of water.
Precursor to polymers
In the plastics industry, Ethylene Glycol is an important precursor to polyester fibers and resins. Polyethylene Terephthalate, used to make plastic bottles forsoft drinks, is prepared from Ethylene Glycol.
Ethylene Glycol is also used in the manufacture of some vaccines, but it is not itself present in these injections. It is used as a minor (1–2%) ingredient in shoe polish and also in some inks and dyes. Ethylene Glycol has seen some use as a rot and fungal treatment for wood, both as a preventative and a treatment after the fact. It has been used in a few cases to treat partially rotted wooden objects to be displayed in museums. It is one of only a few treatments that are successful in dealing with rot in wooden boats, and is relatively cheap.
Ethylene Glycol, is commonly used in acrylic paints, tile grout, primer, sealant paste, floor polish, tyre sealant and as a solvent used in latex paints.
When new paint is drying, indoor VOC levels can be 1000 times higher than outdoor levels. Paint releases VOCs into the air. Because of the large surface areas typically covered by paint in a room, VOC emissions can be significant.
A room that is 12x12 feet will have a painted wall and ceiling surface are close to 432 ft2 which is three times the exposed area of a flooring or ceiling product. Since paints are often applied in occupied spaces, and VOC emissions can continue even 6 months after application, people are more likely to be exposed to vapors from freshly painted surfaces.
Many paint manufacturers market their products as "No-VOC" or"VOC-free." The initial perception is that a product marketed in this manner does not contain any VOCs and, therefore, will not contribute VOCs into the indoor environment. However, these claims usually refer to content, and recent studies have shown that products can still release VOCs into the air.
Technical - Ethylene Glycole - C2H4O + H2O → HO–CH2CH2–OH
- Colourless syrup, sweet-tasting liquid
- CAS Number: 107-2-1
LTEL - 20ppm (52mg / m3)
STEL - 40ppm (104mg / m3)
- Risk Phrases: R22, 36
- Safety Phrases: S26, 36, 37, 39, 45, 53
Ethylene Glycol is an organic compound widely used as antifreeze and a precursor to polymers. In its pure form, it is an odourless, colourless, syrupy, sweet-tasting liquid. Ethylene Glycol is however toxic.
Ethylene Glycol is “hygroscopic” i.e. it absorbs water from the atmosphere. This property is exploited in some cosmetics, food and pharmaceuticals, where small amounts are added to retain moisture. Ethylene Glycol can also be used to remove moisture from natural gas during its processing. Ethylene Glycol has good solvent properties and is used widely in paints, lacquers, dyes and inks. Because it is a both solvent and has a low freezing point it is widely used in antifreeze solutions and as an engine coolant. Antifreeze solutions for cars may have an Ethylene Glycol content of 50%, while windscreen wash may contain up to 14% Ethylene Glycol by weight. A number of chemicals are made using Ethylene Glycol; primarily polyester fibres and Polyethylene Terephthalate (a plasticiser).
Synonyms: 1,2-Dihydroxyethane, 1,2-Ethanediol, EG, Ethane-1,2-Diol, Dlycol, Glycol Alcohol, Monoethylene Glycol, Ethylene alcohol, MEG, Norkool, Tescol, Dowtherm SR 1, Du Pont Zonyl FSO, Fridex, Ucar 17, antifreeze.
Industrial production of Ethylene Glycol is substantial; global capacity was over 18 million tonnes in 2005.