Alcohol fuel

Rising energy prices and global warming have led to increased interest in alternative fuels. 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. Generally speaking, the chemical formula for alcohol fuel is CnH2n+2O. The larger n is, the higher the energy density.

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 advantage that its energy density 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 those 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 still in developmental and research stages. Use of optimized crops with higher yields of energy, elimination of pesticides and fertilizers based on petroleum, and a more rigorous accounting process will help improve the feasibility of bioalcohols as fuels.