Ethyl tert-butyl ether

Ethyl tert-butyl ether (ETBE) is commonly used as an oxygenate gasoline additive in the production of gasoline from crude oil. ETBE offers equal or greater air quality benefits as 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.

Synthesis
It is synthesized by mixing ethanol and isobutylene and reacting them with heat over a catalyst.



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. However, (bio)ethanol makes ETBE partially a biofuel, while MTBE is entirely a fossil fuel and introduces a risk to the environment (see the article on MTBE).