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
Abbreviations
SciTech
Research Acetylene