What is propylene glycol?

Propylene glycol, which is a colorless viscous liquid under normal conditions, is almost odorless, has a slight sweetness, is highly hygroscopic, and is miscible with water, ethanol and various organic solvents. Propylene glycol is divided into 1,2-propanediol and 1,3-propanediol. The common one on the market is 1,2 propanediol, and the molecular formula is C3H8O2.