Overview

Methyl-t-butyl ether (METH-el TER-she-air-ee BYOO-till EE-thur) is a volatile (evaporates easily), colorless, flammable liquid that forms an azeotropic mixture with water. Azeotropic mixtures are combinations of two or more liquids that boil at the same temperature and, therefore, cannot be easily separated from each other.

Key Facts

Other Names:

MTBE; see Overview for additional names

Formula:

(CH₃)₃COCH₃

Elements:

Carbon, hydrogen, oxygen

Compound Type:

Ether

State:

Liquid

Molecular Weight:

88.15 g/mol

Melting Point:

−108.6°C (−163.5°F)

Boiling Point:

55.0°C (131°F)

Solubility:

Soluble in water; very soluble in ethyl alcohol and ether

MTBE was first synthesized in the 1960s by researchers at the Atlantic Richfield Corporation (now ARCO) as an additive designed to increase the octane number (fuel efficiency) of gasoline. The compound was created as a replacement for tetraethyl lead (Pb(C₂H₅)₄), which had long been added to gasolines to improve their octane number. Tetraethyl...