A glycol molecule is made of two hydroxy (OH) groups and carbon atoms of varying sizes and structures. It belongs to an alcohol family of organic compounds. The most basic of glycol compounds is ethylene glycol. Ethylene glycol, which has the molecular formula HOCH2CH2OH, is also known as a 1,2-ethanediol.
Besides ethylene glycol, the other common members of the glycol family are propylene glycol, 1, 3-butanediol and 1, 4-butanediol. Each of these glycols has unique characteristics. For instance, ethylene glycol is oily and colorless with a sweet scent. Commercially, ethylene glycol is manufactured from ethylene oxide. Its key areas of use are as an antifreeze in automobile cooling systems. Ethylene glycol is also used to make fibers and low-freezing explosives. Care should be taken when using ethylene glycol since some of its derivatives could be mildly toxic. The other glycol is propylene glycol, which is similar to ethylene glycol in its physical properties. However, it is not harmful in any way. Thus, propylene glycol is extensively used in foods, cosmetics, solvents and as a component of oral hygiene products. It is also used as a preservative and moisturizing agent. Its source is propylene. Glycols used as antifreeze lowers the freezing point of water thereby offering protection against the effects of ice formation on systems such as car radiators.