Propylene Glycol – PG is a derivative of propylene oxide (PO) and is produced in a two-step process. The first step is the reaction of PO with water into a mixture of Monopropylene glycol and Dipropylene glycol and the second step is the distillation and purification of the mixture into its two separate components (Mono- and Dipropylene glycol). It is a colorless, viscous and odorless liquid. It is highly hygroscopic and miscible in all ratios with water, alcohols, esters, ketones and amines. It has limited miscibility with halogenated hydrocarbons and is not miscible with aliphatic hydrocarbons.