Isobutanol (IUPAC nomenclature: 2-methyl-propan-1-ol; also known as 2-methylpropyl alcohol, among other names) is a colorless, flammable, organic compound with a characteristic smell. Its isomers are 1-butanol, 2-butanol and tert-butanol. It is classified as an alcohol and as such it is widely used as a solvent in chemical reactions, as well as being a useful starting material for organic synthesis.