Applications
45 % of propylene glycol produced is used as chemical feedstock for the production of unsaturated polyester resins. In this regard, propylene glycol reacts with a mixture of unsaturated maleic anhydride and isophthalic acid to give a copolymer. This partially unsaturated polymer undergoes further crosslinking to yield thermoset plastics. Related to this application, propylene glycol reacts with propylene oxide to give oligomers and polymers that are used to produce polyurethanes.
Propylene glycol is considered Generally Recognized As Safe by the U.S. Food and Drug Administration, and it is used as a humectant (E1520), solvent, and preservative in food and for tobacco products. It is also used in pharmaceutical and personal care products. Propylene glycol is a solvent in many pharmaceuticals, including oral, injectable and topical formulations, such as for diazepam and lorazepam that are insoluble in water, use propylene glycol as a solvent in their clinical, injectable forms
Like ethylene glycol, propylene glycol is able to lower the melting point of water, and so it is used as aircraft de-icing fluid. It is similarly used as automotive antifreeze.
Propylene glycol is an ingredient in the oil dispersant Corexit, used in great quantities during the Deepwater Horizon oil spill
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