Diethylene Glycol

(HOCH₂CH₂)₂O

Diethylene glycol (DEG) is an organic compound with the formula (HOCH2CH2)2O and is derived as a co-product with ethylene glycol (MEG) and triethylene glycol.

It is an excellent solvent for many relatively insoluble substances such as nitrocellulose, resins, dyes, oils, and other organic compounds and is used as a humectant (a substance used to keep things moist) for products such as tobacco, cork, printing ink, and glue.

It is also a component in brake fluid, lubricants, wallpaper strippers, artificial fog and haze solutions, and heating/cooking fuel.

The colourless, practically odourless, poisonous, and hygroscopic liquid has a sweetish taste and is used in the manufacture of saturated and unsaturated polyester resins, polyurethanes, and plasticisers.

It is miscible in water, alcohol, ether, acetone, and ethylene glycol.
In the home you may find DEG in personal care products such as skin creams and lotions, or deodorants. However, DEG is often replaced by selected diethylene glycol ethers.

Because of its toxicity, DEG is not allowed to be used in food and drugs as ingestion can affect the central nervous system, heart, respiratory system, liver, pancreas, and kidneys.

An example of this was in 1969 in Cape when seven children developed vomiting, diarrhoea, and dehydration, and died of kidney failure after administration of over-the-counter sedatives. Laboratory testing found DEG instead of propylene glycol in the sedatives.