Butanol
From Free net encyclopedia
Butanol is a higher alcohol with a 4 carbon atom structure and a general formula of C4H10O. There are 4 different isomeric structures for butanol:
butan-1-ol CH3-CH2-CH2-CH2-OH (also n-butanol)
butan-2-ol CH3-CH2-CH(OH)-CH3 (also sec-butanol)
isobutyl alcohol CH3-CH-CH3
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CH2OH
OH
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tert-butyl alcohol CH3-C-CH3
(also t-butanol) |
CH3
These butanol isomers, due to their different structures, have somewhat different melting and boiling points. All are moderately miscible in water, less so than ethanol, and more so than the higher (longer carbon chain) alcohols. Like most alcohols, butanol is poisonous.
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Uses
Butanol sees use as a solvent for a wide variety of chemical and textile processes, as a paint thinner, as well as a component of hydraulic and brake fluids. It is also used as a base for perfumes, but on its own has a highly alcoholic aroma.
Butanol may also be used as a direct fuel in any standard internal combustion engine engineered for gasoline usage (such as a modern automobile). Butanol is reported to yield 36,000 kJ/kg (15,500 BTU/lb) when burned. This can be expressed volumetrically as 29,200 kJ/l (104,800 BTU/US gal).
Production
Butanol can be produced by fermentation of biomass with the bacterium Clostridium acetobutylicum, also known as the Weizmann organism, as it was Chaim Weizmann who first used this bacteria for the production of acetone from starch to make TNT in 1916. The butanol was a side effect of this fermentation (twice as much butanol was produced). The process also creates a recoverable amount of H2.
Most butanol consumed in the United States is currently produced commercially by derivative from fossil fuels. However, a recent advance in fermentation techniques may change the feedstock of butanol in America from petrochemical to biomass in the coming years. David Ramey of Ohio and his company, Environmental Energy, inc. have developed a two stage fermentation process.
In this process, biomass feedstock is first fed to the bacteria Clostridium tyrobutyricum, where a large percentage is converted into butyric acid and hydrogen. In the second process, the butyric acid is fed to the bacteria Clostridium acetobutylicum, where it is converted into butanol. Ramey has claimed a 42% butanol yield from this process.
Comparitively, in Ramey's process, a bushel of corn (maize) produces 2.5 US gallons (370 l/Mg), as opposed to 1.3 US gallons per bushel (190 l/Mg)in a traditional fermitive process. At 2.5 US gallons per bushel, Ramey's anaerobic fermentation process produces a comparable volume of butanol as compared to the same volume of ethanol produced from a bushel of corn in the traditional fermentative process.