Alcohol, or ethyl alcohol,( CaHgO), is the intoxicating part of all liquids that have undergone vinous fermentation, may be extracted by distillation, and is a limpid colourless liquid, with an agreeable smell and a strong pungent taste. When brandy, whisky, and other spirituous liquors, themselves distilled from cruder materials, are redistilled, highly volatile alcohol is the first product to pass off. The alcohol thus obtained contains much extraneous matter, including water, from the first as much as 20 or 25 per cent, and increasing greatly as the process continues. Charcoal and carbonate of soda put in the brandy or other liquor, partly retain the fusel-oil and acetic acid it contains. The product thus obtained by distillation is called rectified spirits or spirits of wine, and contains from 55 to 85 per cent of alcohol, the rest being water. By distilling rectified spirits over carbonate of potassium, powdered quicklime, or chloride of calcium, the greater part of the water is retained, and nearly pure alcohol passes over. It is only, however, by repeated digestion with desiccating agents and subsequent distillation that the last traces of water can be removed.
The specific gravity of alcohol varies with its purity, decreasing as the quantity of water it contains decreases. This property is a convenient test of the alcoholic strength of liquors that contain only alcohol and water; but on account of the condensation that invariably takes place on the mixture of these two liquids, it can be applied only in connection with special tables of reference, or by means of an instrument specially adapted for the purpose (known as an alcoholometer.) By simple distillation the specific gravity of alcohol can scarcely be reduced below .825 at 60 degrees Fahrenheit; by rectification over chloride of calcium it may be reduced to .794; as it usually occurs it is about .820. Alcohol is composed of carbon, hydrogen, and oxygen, in the proportions expressed by the formula CaHgO. Under a barometric pressure of 29.5 inches it boils at 173 degrees Fahrenheit or 78.4 degrees Centigrade; in the exhausted receiver of an air-pump it boils at ordinary temperatures. The freezing of alcohol is effected only at the very low temperature of -203 degrees Fahrenheit. Its very low freezing-point renders it valuable for use in thermometers suited for very low temperatures.
Alcohol vapour is extremely inflammable, and burns with a pale-blue flame, scarcely visible in bright daylight. It occasions no carbonaceous deposit upon substances held over it, and the products of its combustion are carbon dioxide and water. The steady and uniform heat which it produces during combustion makes it a valuable material for lamps. It dissolves the vegetable acids, the volatile oils, the resins, extractive matters, and many of the soaps; the greater number of the fixed oils are taken up by it in small quantities only, but some are dissolved largely. When alcohol is submitted to distillation with certain acids a peculiar compound is formed, called ether. It is alcohol which gives all intoxicating liquors the property whence they are so called. Alcohol acts strongly on the nervous system, and though in small doses it is stimulating and exhilarating, in large doses it acts as a poison. In medicine it is often of great service.
The name alcohol is also applied in chemistry to a large group of compounds of carbon, hydrogen, and oxygen, whose chemical properties are analogous to those of common or ethylic alcohol. Research Alcohol
Abbreviations
SciTech
Research Alcohol