Octane flammability limits

Ethers are relatively uncommon atmospheric pollutants, although the flammability hazard of diethyl ether vapor in an enclosed work space is well known. In addition to aliphatic ethers, such as dimethyl ether and diethyl ether, several alkenyl ethers, including vinylethyl ether, are produced by internal combustion engines. Methyltertiarybutyl ether, MTBE, became tiie octane booster of choice to replace tetraethyllead in gasoline. Because of its widespread distribution, MTBE has the potential to be an air pollutant, although its hazard is limited by its low vapor pressure. Largely because of its potential to contaminate water, MTBE was proposed for phaseout by both the state of California and the U.S. Environmental Protection Agency in 1999. Ethers are relatively unreactive and not as water-soluble as the lower alcohols or carboxylic acids. 

---