Propylene Glycol has many uses. Recently it was used in the gulf cleanup as an oil dispersant. Propylene glycol is also used as a moisturizer, emulsifier and carrier for fragrance oils in personal care and pharmaceutical products. For fragrance oils used in candles we suggest DPG. Furthermore, propylene glycol is used to create fake smoke for movies and is even used in electronic cigarettes as a base that the nicotine is dispersed in.

Unlike ethylene glycol, propylene glycol has a low toxicity and is biodegradable making it a great alternative for antifreezes, deicers and is often used in solar water heating systems and liquid cooling systems.

Propylene glycol is a clear, colorless and hygroscopic liquid.

Propylene glycol is considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration, and it is used as an humectant, solvent, and preservative in food and for tobacco products, as well as being one of the major ingredients of the "e-liquid" used in electronic cigarettes along with vegetable glycerin. Vaporizers used for delivery of pharmaceuticals or personal care products often include propylene glycol among the ingredients they are filled with. Propylene glycol is used as a solvent in many pharmaceuticals, including oral, injectable and topical formulations, such as for diazepam and lorazepam which are insoluble in water.

Propylene glycol is used in veterinary medicine as an oral treatment for hyperketonaemia in ruminants.

CAS: 57-55-6
aka Propylene glycol; α-Propylene glycol; 1,2-Propanediol; 1,2-Dihydroxypropane; Methyl ethyl glycol (MEG); Methylethylene glycol

Reference
wikipedia