Rising energy prices and environmental problems have led to increased interest in alcohol as a fuel. Alcohol has been used as a fuel in other points in history but fossil fuels have become the dominant energy resource for the modern world. Much attention has been placed on the prospects of using ethanol as fuel for cars.
The first four aliphatic alcohols (methanol, ethanol, propanol, and butanol) are of interest as fuels because they can be synthesized biologically, and they have characteristics which allow them to be used in current engines. One advantage shared by all four alcohols is octane rating. Biobutanol has the additional attraction that its energy per kilogram is closer to gasoline than the other alcohols (while still retaining over 25% higher octane rating).
Alcohol fuels are usually of biological rather than petroleum sources. When obtained from biological sources, they are sometimes known as bioalcohols (e.g. bioethanol). It is important to note that there is no chemical difference between biologically produced alcohols and that obtained from other sources. However, ethanol that is derived from petroleum should not be considered safe for consumption as this alcohol contains about 5% methanol and may cause blindness or death. This mixture may also not be purified by simple distillation, as it forms an azeotropic mixture.
Bioalcohols are not used in most industrial processes, as alcohols derived from petroleum are usually cheaper in the current economic millieu. Many economists argue that this fact illustrates the economic infeasibility of using bioalcohol as a petroleum substitute and argue that government programs that mandate the use of bioalcohol are simply agricultural subsidies. [citation needed] Lines of counter-argument point out that estimations of feasibility assume the current, status quo infrastructure, which already exists, and therefore is not an initial cost.[citation needed]
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