Propylene glycol and ethylene glycol are the two most used chemicals for coolants in both anti-freeze for cars and industrial cooling operations. Propylene glycol is considered toxic. Propylene glycol is a glutinous, colorless liquid, which is nearly odorless but possesses a subtly sweet taste.
Its chemical formula is CH2OH. It contains two alcohol groups, as it is classified as a diol. It is mixable with a wide range of solvents, including water, acetone, and chloroform.
Ethylene glycol is an organic compound mostly employed for two purposes, as a raw material in the manufacture of polyester fibers and anti-freeze formulations. It is an odorless, colorless, sweet-tasting viscous liquid.