Ethanol alcohol-gasoline blends

Production of Alcohols by Hydration ofAlkenes. Several alcohols (ethyl alcohol, isopropyl alcohol, sec-butyl alcohol, ferf-butyl alcohol) are manufactured commercially by the hydration of the corresponding olefins.2 45 46 Ethanol, an industrial solvent and a component of alcohol-gasoline blends, and isopropyl alcohol—a solvent and antiknock additive—are the most important compounds. Isopropyl alcohol is often considered the first modem synthetic petrochemical since it was produced on a large scale in the United States in the 1920s. 

For the 10% alcohol-gasoline blends, a formula for the gasohol fuels for automotive use, as well as for some industrial applications, anhydrous ethanol is required because this is miscible with gasoline and many other nonpolar solvents. The presence of even a trace of water in the alcohol or the hydrocarbon component causes a water-rich phase to separate from the composite fuel. 

Capacity Limitations and Biofuels Markets. Large biofuels markets exist (130—133), eg, production of fermentation ethanol for use as a gasoline extender (see Alcohol fuels). Even with existing (1987) and planned additions to ethanol plant capacities, less than 10% of gasoline sales could be satisfied with ethanol—gasoline blends of 10 vol % ethanol the maximum volumetric displacement of gasoline possible is about 1%. The same condition apphes to methanol and alcohol derivatives, ie, methyl-/-butyl ether [1634-04-4] and ethyl-/-butyl ether. 

Oxygen was added as oxygenated hydrocarbon components methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), ethyl tert-butyl ether (ETBE), di-isopropyl ether (DIPE), ethanol, methanol, and tertiary butyl alcohol (TBA). The properties of oxygenates, as they relate to gasoline blending, are shown in Table 10-1. 

Ethanol, or grain alcohol, is an alcohol fuel widely used as automotive fuel. It can be made from a variety of feedstocks, mainly grains, forest resides, and solid waste. It can be used in its pure form, but is more widely used in a blended form. Gasoline blends (90% gasoline/10% ethanol) have been widely used in many areas of the country. Ethyl tertiary butyl ether (ETBE) is a feedstock for reformulated gasoline based on ethanol. 

The predominant method of ethanol manufacture, at one time, was by fermentation of sugars this method went out of use in the 1930s. However, com fermentation is now a source of 92% of all ethanol and is used for gasohol, a 10% alcohol 90% gasoline blend used for automobile fuel. 

The ether process combines an alcohol with an iso-olefin. In the United States, a weight percentage of oxygenate (2 wt.%) content is mandated for reformulated gasoline (RFG). The most common oxygenate currently used is methyl tertiary butyl ether (MTBE). Methanol and the iso-olefin form of isobutylene are reacted to form MTBE. Other alcohols, such as ethanol, may be reacted with iso-butylene to form ethyl tertiary butyl ether (ETBE). Methanol can be reacted with iso-amylene, another iso-olefin, to form tertiary amyl-methyl ether (TAME). Of all the mentioned ethers, MTBE is the one most widely used as a gasoline-blending component.16... 

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