Methyl ethyl ketone is an organic compound with the chemical formula CH3COCH2CH3 and a molecular weight of 72.11. It is a colorless and transparent liquid with an odor similar to acetone. Easy to evaporate. Can be miscible with ethanol, ether, benzene, chloroform, and oils. Dissolved in 4 parts of water, but its solubility decreases with increasing temperature, and it can form an azeotrope with water. Low toxicity, median lethal dose (rat, oral) 3300mg/kg. Flammable, vapor can form explosive mixtures with air. High concentration steam has anesthetic properties.