2-Butanol, or sec-butanol, is an organic compound with formula CH₃CH(OH)CH₂CH₃. This secondary alcohol is a flammable, colorless liquid that is soluble in 3 parts water and completely miscible with polar organic solvents such as ethers and other alcohols. It is produced on a large scale, primarily as a precursor to the industrial solvent methyl ethyl ketone. 2-Butanol is chiral and thus can be obtained as either of two stereoisomers designated as (R)-(-)-2-butanol and (S)-(+)-2-butanol. It is normally found as an equal mixture of the two stereoisomers — a racemic mixture.