Propylene glycol is an organic compound with the chemical formula c3h8o2, which is miscible with water, ethanol and a variety of organic solvents. Under normal conditions, it is colorless viscous liquid, almost tasteless and slightly sweet. Propylene glycol can be used as raw material of unsaturated polyester resin. It can be used as wetting agent in cosmetics, toothpaste and soap together with glycerol or sorbitol. In hair dyes, it is used as moisture regulating and hair leveling agent, antifreeze, cellophane, plasticizer and pharmaceutical industry.