Acetone is the simplest and most important of the ketones. It is a colourless liquid with a mildly pungent and somewhat aromatic odour. It is primarily used as a chemical intermediate and as a solvent for celluloseacetate and nitro-cellulose. It is used as a carrier for acetylene, and as a raw material for the chemical synthesis of a wide range of products such as ketene, methyl methacrylate, bisphenol A, diacetone alcohol, mesityl oxide, methyl isobutyl ketone, hexylene glycol, and isophorone.
Acetone is a mobile, flammable liquid that is miscible in all proportions with water and with organic solvents such as ether, methanol, ethyl alcohol, and esters. It is incompatible and reactive with oxidisers and acids. Containers of acetone may explode in a fire, producing poisonous gases. Acetone fires may be controlled with carbon dioxide or dry chemical extinguishers.
Acetone undergoes many condensation reactions; in the presence of an amine, or ammonia, various esters condense readily with acetone. Acetone is also known commercially as dimethyl ketone, methyl ketone, dimethylformaldehyde, ketone propane, and 2-propanone.
Acetone is formed in the humanblood when the body uses fat instead of glucose for energy. If
acetone forms, it usually means that the cells do not have enough insulin, or cannot use the insulin that is in the blood, to use glucose for energy. Acetone passes through the body into the urine. Someone with a lot of acetone in the body can have breath that smells fruity and is called '
acetone breath'.
Acetone is used in painting and decorating for scrubbing the surface of certain woods, such as cedar and teak, prior to painting them. Research Acetone
Acetylene is a highly inflammable gas of the hydrocarbon family used for welding and cutting metals. It was discovered by Berthelot. In 1862 Friedrich Wohler discovered that carbide of calcium treated with water produced lime and acetylene. In 1895 acetylene was cheaply produced on a commercial scale and subsequently was used for general lighting.
Acetylene is colourless, and has a rather pleasant ethereal smell when pure, but as ordinarily prepared it is not quite pure, containing small quantities of sulphuretted and phosphuretted hydrogen, and having a strong and disagreeable odour. It can be liquefied by cold and pressure, and may even be obtained in the solid form as a snow-like mass. It is one of the constituents of ordinary coal-gas, but is present in very small quantities. It burns readily, being ignited at a temperature below that at which coal-gas is ignited. If there is not a sufficient supply of air the flame is dull and very smoky, but when a proper burner is used acetylene gives a very white and brilliant flame, its illuminating power being far higher than that of coal-gas. It possesses properties that may render it dangerous in certain circumstances, and these have to be guarded against. The gas itself may be made to explode by (a) high temperature and great pressure, and (b) a detonation some little distance away, and in the liquid form the risk of explosion is so great that in Britain and elsewhere liquid acetylene is forbidden to be stored and used. When mixed with chlorine it explodes spontaneously. Like other combustible gases it forms an explosive mixture with air.
Acetylene has been known for a considerable time, and may be produced in various ways, but only in the late 19th century did it come into extensive use as an illuminant, and only since a cheap method of producing carbide of lime (calcium carbide) was discovered, the gas being readily prepared by bringing this substance into contact with water. Calcium carbide was manufactured by subjecting a mixture of coke and lime to the heat of an electric furnace, and when it is brought into contact with water the carbide is decomposed, and acetylene and lime or hydrate of lime are produced. To provide a supply of acetylene gas for lighting purposes various forms of generator were in use, and in these the carbide was either brought slowly into contact with the water, or the water was brought gradually into contact with the carbide, or the two was brought together at intervals and again separated. The gas had to be evolved at a low temperature, and under a low pressure, and in the absence of air. Before being used it had to be purified by passing it through suitable substances. A dry process of production was introduced in the late 19th century. Several kinds of burners and lamps were used, and portable lamps were quite common by 1900. Country mansions and such detached residences were often lighted by acetylene gas. A license was required to enable a person to keep more than 28 lbs. of calcium carbide stored in any building. Research Acetylene
Calcium Carbide is a substance formed by heating quicklime and carbon in an electric furnace. It is a greyish crystalline substance which decomposes immediately on coming into contact with water, generating acetylene. Research Calcium Carbide
1,1,2,2-Tetrachloroethane is a man-made colourless or pale yellow dense liquid with a penetrating, sweet chloroform-like odour. The only major use for it is as a feedstock in the production of trichloroethylene, tetrachloroethylene, and 1,2-dichloroethylene. It may also be used as a solvent; in cleaning and degreasing metals; in paint and rust removers, varnishes and lacquers; in photographic films; and as an extractant for oils and fats. It was once an ingredient in an insect repellent, but registration was cancelled in the late 1970s. Due to its toxicity and new processes for manufacturing chlorinated ethylenes, the manufacture and use of 1,1,2,2-tetrachloroethane now appears to be very limited. 1,1,2,2-Tetrachloroethane does not burn easily, but produces poisonous gases in a fire, including phosgene and hydrogen chloride. It is soluble in alcohol and ether. It is also known as acetylene tetrachloride; di-chloro-2,2-dichloroethane; s-tetrachloroethane; TCE
tetrachloroethane; and sym-tetrachloroethane. Research Tetrachloroethane
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Acetone
