Propylene glycol is a synthetic liquid organic compound with the molecular formula C3H8O2 or CH3CHOHCH2OH. Its CAS is 57-55-6. The clear, colorless, slightly syrupy liquid that readily absorbs water is also used to make polyester compounds, and as a base for deicing solutions.
The chemical, food, and pharmaceutical industries use propylene glycol as antifreeze when leakage might lead to contact with food. It is also used to create artificial smoke or fog for fire-fighting training and in theatrical productions.
Propylene glycol is also recognized as 1,2-dihydroxypropane, 1,2-propanediol, methyl glycol, and trimethyl glycol. The only industrial process used for manufacturing propylene glycol is by direct hydrolysis of propylene oxide with water.