Surely very many people know that the word itself - acetylene - is associated with the concept of "vinegar". But the fact that today acetylene is the only substance that can burn in the absence of air access, and which is widely used in industry, is far from everyone knows. Acetylene is dangerous, this is also emphasized by the fact that, for example, its combustion in acid creates a flame with a temperature of up to 3100 ° C.
The first receipt of acetylene was carried out by Edmund Davy in the distant 1836. Devi acted on potassium carbide with an ordinary aqueous solution, a reaction occurred, the equation of which can be written as: K2C2 + 2H2O = C2H2 + 2KOH. As a result, a gas was obtained whose formula is C2H2 and to which the scientist gave the name bicarbon hydrogen.
With the discovery of the doctrine of radicals, Justus Liebig called one of the groups of atoms (radicals) acetyl, however, he considered a compound with the formula C2H3. The substance that Devi received was considered by chemists as a derivative of acetyl. Then, when the production of acetylene was carried out by the Frenchman Marcelin Berthelot in several ways, the substance got its name, which is used in chemistry to this day. Berthelot considered the resulting compound as an acetyl molecule, from which a hydrogen atom was taken . Technologically, the production of Berthelot acetylene was the following process. He passed pairs of preheated alcohols - methyl and ethyl - through a tube also heated to high temperature.
A little later, in 1862, acetylene was synthesized by an electrochemical reaction, during which hydrogen was passed between electrodes made of carbon. These technologies at that time were very expensive and inefficient, and therefore could only be considered as a theoretical solution to the problem. Only at the very end of the century before last, a method was invented that made it possible to establish a more economical production of acetylene. This method is based on calcining a mixture of quicklime and coal. This allowed us to establish the use of the compound as a gas for street lighting. The fact is that a gas that contained about 92.3% carbon in its composition released a huge amount of this substance in solid form at high temperature. It is they who give a fairly bright light. In this case, the combustion temperature determines not only the brightness of the combustion, but its color. The higher the temperature, the more the glow color of the carbon particles is. The resulting heating pads filled with acetylene could give about fifteen times more light than the gas lamps circulated then. Even when they were supplanted by electric lighting, the use of acetylene for lighting continued in bicycle lights and omnibuses.
As industry developed, more and more quantities of a compound such as acetylene were required. Getting it in industrial volumes began only in the last century. As a result of this “breakthrough”, the compound was also used for technical needs. For construction needs, acetylene was prepared by quenching carbide with water. This product is known to many for its very unpleasant odor due to the impurities of ammonia and hydrogen sulfide contained in it. In fact, a chemically pure substance has a mild ethereal odor. It is lighter than air, the molecular weight of acetylene is 26.038. The gas has no color, it is soluble in many liquid solutions, and the solubility is determined by the temperature of the solution itself.
Modern technologies include the production of acetylene from methane by electrocracking, a process in which methane gas is first passed between the electrodes at a temperature of at least 1600 ° C. Then, in order to prevent decomposition of acetylene, the gas is subjected to rapid cooling. This method is effective in that part of the heat energy obtained by the combustion of a substance can be directed to heating the next reaction cycle, providing a continuous nature of its course.
Acetylene is widely used in welding and cutting metals, to obtain very bright white light, for the production of explosive materials.