Methyl tert-butyl ether (MTBE) is an organic compound with the chemical formula C₅H₁₂O. It is a colorless, transparent liquid, insoluble in water but easily soluble in ethanol and ether. It is an excellent high-octane gasoline additive and anti-knock agent.

Chemical formula: C₅H₁₂O

Molecular weight: 88.148

CAS number: 1634-04-4

Uses:

Primarily used as a gasoline additive, it has excellent anti-knock properties, improves octane rating, and can also be cracked to produce isobutylene. It has good miscibility with gasoline, low water absorption, and is non-polluting to the environment. It can be used as an analytical solvent, extraction agent, and as a mobile phase in chromatography, especially in high-performance liquid chromatography. It forms azeotropes with some polar solvents such as water, methanol, and ethanol. Methyl tert-butyl ether also has mild effects.