Butanone, most commonly known as methyl ethyl ketone or simply MEK, is an organic compound commonly used as a polar solvent and lab reagent. This clear liquid is an example of a ketone, and is similar to acetone.
Methyl ethyl ketone is a clear, colorless fluid that is less viscous than water and has a somewhat sharp, sweet odor characteristic of most ketones, with some describing it as similar to butterscotch. Compared to acetone it is much less volatile and is less soluble in water(approximately 27.5g/100mL at room temperature). It is a useful solvent for the extraction of gums and oils from plants and for cleaning residues off of metal and glass, hence why it is often found as a cleaner or a component of lacquers.
Methyl ethyl ketone can be purchased at some hardware stores as simply "MEK". It is also a component of some paint thinners and degreasers. Some hobby stores, such as those that carry modelling kits made of polystyrene or acrylic, carry methyl ethyl ketone as a plastic welding solvent, but this is usually more expensive than finding it at a hardware store.
Butanone is prepared industrially through the oxidative dehydrogenation of 2-butanol, but for use as a reagent or solvent is typically just purchased.
Methyl ethyl ketone is a skin and respiratory irritant. At very high concentrations it poses health problems, may cause birth defects in animals.
MEK is highly flammable and should not be handled near any open flame or strong oxidizing agents.
MEK should be stored in a closed bottle, in a dark place.
MEK can be safely burned.