It is a colourless stable, non toxic hygroscopic heat transfer liquid with complete water solubility used as an antifreeze in refrigeration systems. It is clear and odourless with complete water solubility. Slightly soluble in aromatic hydrocarbon solvents and only slightly miscible with aliphatic hydrocarbon solvents. Propylene glycol is used as an organic solvent and diluent in pharmaceuticals and many other industrial applications.