In the list of hydrocarbons, methane and acetylene play an important role in various fields of the chemical industry. Initially, methane was not of any practical interest. It was called both swamp and mine gas by the place where it was most often found in nature. As a rule, this compound caused a lot of trouble due to its physical and chemical properties. Without color and odorless, methane could cause a person to have a slight malaise, and even serious poisoning. But a lot of trouble brought the gas with its ability to form a flammable cocktail with great destructive abilities in a mixture with air.
Despite the fact that methane has found many ways to use, the industrial production of this substance has no value. The fact is that this compound is not only often found in nature, but is also an accompanying (by-product) product in various technological processes of the modern chemical industry.
Skewer in 1860 was able to carry out a reaction, which subsequently gained important industrial significance. But in those days, the process allowing the chemical transition methane> acetylene to be carried out did not receive much enthusiasm. The fact is that to ensure the need for acetylene, the carbide method for its preparation was sufficient.
The modern chemical industry has found many ways to use acetylene. This is gas cutting, and its use in bright chemical lamps, and the use in the production of a wide variety of chemicals. Acetylene is in demand in the production of a wide variety of explosive compounds and acetic acid, ethyl alcohol and solvents, rubber and aromatic hydrocarbons. A manifestation of the achievements of the twentieth century was the use of acetylene in the production of polymers.
The time has come to recall the chemical transformation of methane - acetylene. Electrocracking and thermo-oxidative cracking are the name of modern technological processes, as a result of which acetylene is obtained from methane. In the first case, a methane gas stream passes through the electrodes at a temperature of 1600 ° C and is rapidly cooled. The implementation of the second method for the conversion of methane - acetylene, incomplete oxidation, favors the release of heat from the partial combustion of acetylene.
In the production chain, methane, acetylene, acetic aldehyde, the last element appeared due to the hydration reaction of acetylene, later called the Kucherov reaction. Acetic aldehyde found industrial application in the production of acetic acid, aldehyde polymers, butadiene, and a number of organic substances.
But the substance itself is unsafe, acetaldehyde is quite toxic even when exposed to the skin. It acts as a serious air pollutant, which it gets when burning, for example, when smoking or from automobile exhausts. A huge amount of it is formed during the heat treatment of various polymers and plastics.
The following chain of methane, acetylene, benzene, chlorobenzene is an additional confirmation of the active use of swamp or mine gas in the modern chemical industry. We are already familiar with the reactions to obtain acetylene from it. It remains only to carry out the trimerization of this gas, passing C2H2 over activated carbon at a temperature of 400 degrees Celsius. The benzene obtained industrially is used for the production of ethylbenzene, cumene, cyclohexane and nitrobenzene. About three percent of this substance is spent on linear alkylbenzenes. And only one percent of benzene is spent on the synthesis of chlorobenzene. For this, the reaction of its chlorination is used. The conditions for its implementation is a temperature of 80-85 ° C and the presence of iron or iron chloride.