propaan12diol

Propane-1,2-diol, commonly known as propylene glycol, is an organic compound with the formula C3H8O2. It contains two hydroxyl groups on adjacent carbon atoms, making it a diol. Industrial samples are typically used as a racemic mixture, since the molecule can exist as two enantiomers at the chiral center.

Propylene glycol is a colorless, viscous liquid that is hygroscopic and has a mild, characteristic odor. It is miscible with water and many organic solvents. Its boiling point is relatively high for an organic liquid, around 188°C, and it is non-volatile at room temperature. The diol’s two hydroxyl groups confer significant hydrogen-bonding, contributing to its solvent and humectant properties.

Industrial production mainly proceeds by hydration of propylene oxide to yield 1,2-propanediol. This can be achieved via direct acid- or base-catalyzed hydration of propylene oxide or through related hydrolysis routes, followed by purification to remove impurities.

Applications of propylene glycol are broad. It is widely used as a solvent and humectant in cosmetics, personal care products, and inks; as afood additive (listed as E1520 in the EU) and as a pharmaceutical excipient; and as a non-toxic antifreeze and heat-transfer fluid in various consumer and industrial products. It also serves as a precursor or co-feed in the synthesis of polymers and polyurethanes.

Safety and regulation: propylene glycol exhibits relatively low acute toxicity and is generally regarded as safe when used within established guidelines for food, cosmetics, and pharmaceuticals. It can be an irritant in concentrated forms and should be handled with proper care.