Glycols

Di Ethylene Glycol

Diethelene glycol (also known as DEG, 2,2-oxydiethanol and glycol ether ether diglycol) is a clear, colourless, odourless liquid with the formula C4H10O3.  It is soluble both in water and in many organic compounds and has hygroscopic properties which makes it a useful industrial chemical.

Production

Production of diethylene glycol is generally based on the demand for, and production of, monoethylene glycol as it is a by-product of this production process.  The process consists of the oxidation of ethylene at a high temperature in the presence of a silver oxide catalyst.  The ethylene oxide is then hydrated to yield diethylene glycol with monoethylene glycol and triethylene glycol as co-products.

The chemical industry tries to maximise the production of monoethylene glycol in this process but diethylene glycol is a very useful by-product.

Storage and Distribution

Di ethylene glycol can be stored in stainless steel, aluminium, or lined drums, tank cars, or tank trucks.  It has a specific gravity of 1.118 and a flash point of 154 °C (closed cup).  It is not regulated for transport on road, rail, air, or sea but it is classified as harmful, and is harmful if swallowed.

Uses

Di ethylene glycol has a variety of uses in industry.  The tobacco industry makes use of its hygroscopic properties and uses it as humectant in tobacco production.  This same property also makes it useful in the treatment of paper, cork, glue, and cellophane and it is utilised as a dehydrant in the natural gas industry where it removes the water from the gas pipelines.

Di ethylene glycol is also used as a chemical intermediate in the manufacture of unsaturated polyester resins, plasticisers, acrylate and methacrylate resins, and urethanes.  In the U.S. and Western Europe 51% of DEG is consumed in this way.

However, in Japan it is most utilised as a cement grinding aid.  It can also be used in petroleum solvent extraction, and can be found in printing ink, and drywall joint compound.

Di ethylene glycol is now being displaced by tri ethylene glycol in some of its applications as the lower toxicity of tri ethylene glycol makes it more appealing to manufacturers.