Propylene (propene) is an unsaturated organic compound having the chemical formula C3H6. It has one double bond, and is the 2nd member of the alkene class of hydrocarbons, as well as second most available organic compound in nature after ethylene.
It is the raw material for a wide variety of products. Manufacturers of the plastic propylene account for nearly two thirds of all demand. Propylene Glycol is a colorless, nearly odorless, clear, viscous liquid with a faintly sweet taste, hygroscopic and miscible with water, acetone, and chloroform.
Industrially propylene glycol is produced from propylene oxide. Different manufacturers use either non-catalytic high-temperature process at 200 °C (392 °F) to 220 °C (428 °F), or a catalytic method, which proceeds at 150 °C (302 °F) to 180 °C (356 °F) in the presence of ion exchange resin or a small amount of sulfuric acid or alkali.