Methyl ethyl ketone is an organic compound with chemical formula CH3COCH2CH3 and molecular weight 72.11. It is a colorless transparent liquid with an odor similar to acetone. Methyl ethyl ketone is volatile. It can be miscible with ethanol, ether, benzene, chloroform and oil. It is soluble in 4 parts of water, but the solubility decreases when the temperature increases, which can form azeotropic mixture with water. Low toxicity, median lethal dose (rats, oral) 3300mg/kg. Flammable, vapors can form explosive mixtures with air. High concentrations of steam are narcotic.