The Safety of Propylene Carbonate

Propylene Carbonate (PC) is a polar aprotic solvent used as a "green" sustainable alternative solvent for chemical transformations. It is a low toxicity, biodegradable, non-corrosive colorless liquid with a steep boiling point.

Propylene Carbonate also has strong stability against reduction as well as a strong dielectric constant, and thereby PC or PC-based mixed solvent systems have been successfully employed as a solvent in primary lithium cells using metallic lithium as negative electrodes.

Due to its low vapor pressure and findings of negligible photochemical reactivity, Propylene Carbonate is an effective substitute for other hazardous solvents such a MEK, methylene chloride, toluene, acetone, NMP, and perchloroethylene. Propylene Carbonate is also compatible with different solvents, providing an efficient ingredient in co-solvent formulations. It is widely used in the manufacture of paints, adhesives, coatings, surface cleaners, degreasers, strippers, and inks formulations as well as in lithium-ion batteries, as electrolytic solvent, and in the removal of carbon dioxide from natural gas.

Besides, Propylene Carbonate is also an ingredient that is used in cosmetics and skincare products. In those products, propylene Carbonate primarily functions as a solvent, meaning that it dissolves different ingredients. It is typically used at concentrations ranging from less than 0.1% to 5%. Propylene Carbonate is used in the formulation of makeup, primarily lipstick, eye shadow, and mascara, as well as in skin cleansing products.

Safety

As for the safety of propylene carbonate, in clinical studies, undiluted propylene carbonate was found to be moderately irritating to the eye and skin, but it was non-toxic by inhalation exposure.

Although products containing up to 20% propylene carbonate were determined to be moderately irritating to human skin, still, they were non-sensitizing, non-phototoxic, and non-photosensitizing. It is worth bearing in mind that this concentration is greatly higher than the concentrations typically used in cosmetic formulations, which range from less than 0.1% to 5%. Thus, according to the evaluating the scientific data, propylene carbonate was safe as a cosmetic ingredient in the present practices of use and concentration.