An Overview of Ethanol
Ethanol, (CH CH OH), is a clear, colourless liquid with a characteristic odour. Ethanol is an alcohol. In a dilute aqueous solution, it has a sweet flavour, but in more concentrated solutions it has a burning taste. Alcohol originally referred to a fine powder, but medieval chemists later applied the term to the refined products of distillation, and this led to its current usage.
Ethanol melts at -114ÃÂ°C, boils at 78.5ÃÂ°C, and has a density of 0.789 g/mL at 20ÃÂ°C. Because of its low freezing point it is useful for the fluid in thermometers for temperatures below -40ÃÂ°C, (the freezing point of mercury), and for other low temperature purposes, such as antifreeze in automobile radiators.
Ethanol has been made since ancient times by the fermentation of sugars. It has two strands of uses; one as a beverage and the other for industrial purposes. All beverage ethanol and more than half of industrial ethanol is still made by the process of fermentation.
Most ethanol not intended for drinking is now made synthetically, either from acetaldehyde made from acetylene, or from ethylene made from petroleum. Ethanol can be manipulated to form acetaldehyde, acetic acid, ether, butadiene, chloroform, and many other organic chemicals.
Ethanol is used as an automotive fuel by itself and can be mixed with gasoline to form "gasohol"- the most common blends contain 10% and 90% ethanol mixed with gasoline. Because the ethanol molecule contains oxygen, it allows for more complete combustion of fuel, resulting in fewer emissions. Ethanol is also called a renewable fuel and therefore has advantages as an automotive fuel.
Ethanol is mixable in all proportions with water and with most organic solvents. It is useful as a solvent for many substances and in making perfumes, paints, lacquer, and explosives.