1,2-Propanediol, Reagent, ACS or propylene glycol is an organic compound and colorless liquid without odor. It has a slightly sweet taste and chemically classed as a diol. It is considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration, and it is used as an humectant (E1520), 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. As an ACS grade quality reagent, its chemical specifications are the de facto standards for chemicals used in many high-purity applications and typically designate the highest quality chemical available for laboratory use. Spectrum Chemical manufactured Reagent ACS grade products meet the toughest regulatory standards for quality and purity.