MEK (butan-2-one, IUPAC) is a colorless liquid with an acetone-like odor. MEK is polar, soluble in water, and has a specific gravity of 0.8, which is lighter than water. It is highly flammable, with a flammable range of 2%-10% in air, a flash point of 1°F (-17°C), and a boiling point of 176°F (80°c). Ignition temperature of MEK is 759°F (403°C), and the vapordensity is 2.5, which is heavier than air. It is toxic by inhalation, with a TLV of 200 ppm in air. The four-digit UN identification number is 1193. The NFPA 704 designation for MEX is health 1, flammability 3, and reactivity 0. The primary uses of MEK are as a solvent and in the manufacture of smokeless powder, cleaning fluids, in printing, and acrylic coatings. The structure and molecular formula for MEK are shown in Figure 5.58.