2Hydroxy2methylpropane

2-Hydroxy-2-methylpropane, also known as tert-butyl alcohol or t-butanol, is a tertiary alcohol with the chemical formula C4H10O. It is the simplest tertiary alcohol, meaning the carbon atom bonded to the hydroxyl group is also bonded to three other carbon atoms. It is one of the four isomers of butanol. At room temperature, tert-butyl alcohol is a solid with a camphor-like odor. It is miscible with water, ethanol, and diethyl ether.

Tert-butyl alcohol is produced industrially by the hydration of isobutylene. It is commonly used as a solvent, a denaturant for ethanol, and as a fuel additive to increase octane rating. It also serves as a precursor in the synthesis of other organic compounds, such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), although the use of MTBE as a gasoline additive has declined due to environmental concerns. In laboratory settings, it is often used as a polar protic solvent.

The presence of the bulky tert-butyl group sterically hinders reactions at the hydroxyl group, making its reactivity different from primary and secondary alcohols. For instance, it is resistant to oxidation under mild conditions. Tert-butyl alcohol is flammable and should be handled with appropriate safety precautions.