Page "Diol" Paragraph 4

In a vicinal diol, the two hydroxyl groups occupy vicinal positions, that is, they are attached to adjacent atoms.

These compounds are called glycols.

Examples include 1, 2-ethanediol or ethylene glycol HO —( CH < sub > 2 </ sub >)< sub > 2 </ sub >— OH, a common ingredient of antifreeze products.

Another example is propane-1, 2-diol or alpha propylene glycol, HO — CH < sub > 2 </ sub >— CH ( OH )— CH < sub > 3 </ sub > used in the food and medicine industry as well as a relatively non-poisonous antifreeze product.