Metüültertbutüüleetri

Metüültertbutüüleetri, also known as MTBE, is an organic compound with the chemical formula (CH3)3COCH3. It is a volatile, flammable, and colorless liquid at room temperature with a distinctive odor. MTBE is synthesized by the reaction of isobutylene with methanol. It was widely used as a fuel additive in gasoline, particularly in the United States, from the 1970s until the early 2000s.

The primary purpose of MTBE as a fuel additive was to increase the octane rating of gasoline, which helps to prevent engine knocking and allows for higher compression ratios. Additionally, MTBE acted as an oxygenate, meaning it provided oxygen to the combustion process. This oxygenation was intended to promote more complete burning of fuel, thereby reducing emissions of carbon monoxide and unburned hydrocarbons. In the United States, its use was mandated by the Clean Air Act Amendments of 1990 to improve air quality.

However, concerns about MTBE's environmental impact led to its decline in use. MTBE is highly soluble in water and can persist in groundwater. Leaks from underground storage tanks and spills during transportation resulted in widespread groundwater contamination. Because of its unpleasant taste and odor even at low concentrations, it made drinking water sources unusable. These environmental issues prompted several states to ban or phase out the use of MTBE. As a result, its use in gasoline has been largely replaced by other oxygenates like ethanol.