The chemical
compound ethanol, also known as ethyl
alcohol or grain alcohol, is the
bio-alcohol found in alcoholic beverages. When non-chemists
refer to "alcohol", they almost always mean
ethanol. It is also increasingly being used as a fuel (usually
replacing or complementing gasoline). Ethanol's chemical formula
is C2H5OH.
Properties as a Solvent
Pure ethanol is a flammable, colorless liquid with a boiling point of 78.5° C. Its low melting point of -114.5° C allows it to be used in antifreeze products. It has a pleasant odor reminiscent of whiskey. Its density is 789 g/l about 20% less than that of water. It is easily soluble in water and is itself a good solvent, used in perfumes, paints and tinctures. Alcoholic drinks have a large variety of tastes, since various flavor compounds are dissolved during brewing. >A solution of 70-85% of ethanol is commonly used as a disinfectant; it kills organisms by denaturing their proteins and dissolving their lipids: it is effective against most bacteria and fungi, and many viruses, but is ineffective against bacterial spores. This disinfectant property of ethanol is the reason that alcoholic beverages can be stored for a long time.
Ethanol can lose a proton from the hydroxyl group and is a very weak acid, weaker than water. The CAS number of ethanol is 64-17-5 and its UN number is UN 1170.
Environmental friendliness
Arguments in favor of ethanol are the search for decreased dependency on oil producing countries and the decreased net ouptut of the greenhouse gas carbon dioxide. Some critics argue that it is mainly a government subsidy for corn-growing agribusiness. The Archer Daniels Midland Corporation of Decatur, Illinois, better known as ADM, the world's largest grain processor, produces 40% of the ethanol used to make gasohol in the U.S.. The company and its officers have been eloquent in their defense of ethanol and generous in contributing to both political parties.
Other critics contend that it is economically absurd to consider ethanol from grain as a replacement for petroleum, when industrial ethanol is made from petroleum feedstocks because it is far cheaper than fermented ethanol. Environmentalists do not like arguments like this, since they advocate a transition to renewable energy rather than continued usage of fossil fuels.
There is widespread belief that ethanol containing fuel is more environmentally friendly than gasoline without additives. However, there is a controversy over whether requiring ethanol in automotive fuel is wise since it has been argued that the beneficial effects of ethanol can be achieved with other cheaper additives made from petroleum. Also, both the Environmental Protection Agency and the National Academy of Sciences have issued "reports showing that adding ethanol to gasoline will at best have no effect on air quality and could even make it worse. Studies show ethanol could even increase emissions of nitrogen oxides and volatile organic compounds, which are major ingredients of smog."
References
1- Ethanol Molecule Summary - PubChem
2- Ethanol CDC -- Occupational Safety and Health