Distillation (Encyclopedia of Science)
Distillation is a technique by which two or more substances with different boiling points can be separated from each other. For example, fresh water can be obtained from seawater (water that contains salts) by distillation. When seawater is heated, water turns into a vapor that can be condensed and captured. The salts in the seawater remain behind.
In contrast to the preceding example, distillation is most commonly used to separate two or more liquids from each other. Imagine a mixture of three liquids, A, B, and C. A has a boiling point of 86°F (30°C); B has a boiling point of 104°F (40°C); and C has a boiling point of 122°F (50°C). Ordinary gasoline is such a mixture, except that it consists of many more than three components.
The three-liquid mixture described above is added to a distillation flask, such as the one in the accompanying figure of the distillation setup. The mixture in the flask is heated by a Bunsen burner or some other apparatus. The temperature of the liquid mixture rises until it reaches the boiling point of any one liquid in the flask. In our example, that liquid is A, which boils at 86°F. Liquid A begins to boil when the temperature in the flask reaches 86°F. It turns into a vapor at that temperature, rises in the distilling flask, and passes out of the flask arm into the condenser....
(The entire section is 804 words.)
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Distillation (Encyclopedia of Drugs, Alcohol, and Addictive Behavior)
Distillation is the process of purifying liquid compounds on the basis of different boiling points or the process of separating liquids from compounds that do not vaporize. Since the actual process causes liquids to precipitate in a wet mist or drops that concentrate and drip, the word derives from the Latin de (from, down, away) + stillare (to drip).
In the simplest form of distillation, saltwater can be purified to yield freshwater by steam distillation, leaving a residue of salt. Distillation is also the process by which alcohol (ethanol, also called ethyl alcohol) as liquors or spirits, are separated from fermenting mashes of grains, fruits, or vegetables. When this process is used to distill alcohol, it is based on the following: Ethyl alcohol (C2H6O) has a lower boiling point than does water (78.5°C versus 100°C), so alcohol vapors rise first into the condenser, where cool water circulates around the outside of the condenser, causing the alcohol vapors to return to liquid form and drop into the collection flask. The purity of the distillate can be increased by repeating the process several times.
About 800 A.D., the process of distillation was evolved by the Arabian alchemist Jabir (or Geber) ibn Hayyah. He may also have named the distillate alcohol, since the word derives from an Arabic root, al-kuhul, which refers to powdered antimony (kohl) used as an eye cosmetic in the Mediterranean region; with time and use it came to mean any finely ground substance, then the "essence," and eventually, the essence of winets spirit, or alcohol. It came into English from Old Spanish, from the Arabic spoken by the Moors of the Iberian peninsula during their rule there (750-1492 A.D.).
(SEE ALSO: Beers and Brews; Distilled Spirits, Types of; Fermentation)
LUC, S. P. (1963). Alcohol and civilization. New York: McGraw-Hill.
SCOTT E. LUKAS