Ethyl tert-butyl ether

Ethyl tertiary-butyl ether (ETBE), also known as ethyl tert-butyl ether, is commonly used as an oxygenate gasoline additive in the production of gasoline from crude oil. ETBE offers equal or greater air quality benefits than ethanol, while being technically and logistically less challenging. Unlike ethanol, ETBE does not induce evaporation of gasoline, which is one of the causes of smog, and does not absorb moisture from the atmosphere.

Production
Ethyl tert-butyl ether is manufactured industrially by the acidic etherification of isobutylene with ethanol at a temperature of 30–110 °C and a pressure of 0,8–1,3 MPa. The reaction is carried out with an acidic ion-exchange resin as a catalyst. Suitable reactors are fixed-bed reactors such as tube bundle or circulation reactors in which the reflux can be cooled optionally.

Ethanol, produced by fermentation and distillation, is more expensive than methanol, which is derived from natural gas. Therefore, MTBE, made from methanol is cheaper than ETBE, made from ethanol.