Acetylene is a substance belonging to the class of alkynes. In other words, it is a hydrocarbon that has a triple bond in each molecule. The chemical formula of acetylene is as follows: C 2 H 2 . In itself, this substance is a colorless gas, which is much lighter than air. Get acetylene from methane. The substance is chemically active and explosive.
How to get acetylene
It is very difficult to get acetylene from methane at home. The simplest method for isolating this gas is the reaction of water with calcium carbide. Many of you probably remember how pieces of this substance were thrown into puddles and what kind of reaction took place. At the same time, there was a rapid hissing. As for calcium carbide, it gradually melted, forming a large amount of foam. A similar reaction can be written as follows:
CaC 2 + 2H 2 O = C 2 H 2 + Ca (OH) 2.
Many use technical calcium carbide, which contains a large amount of impurities. As a result of this, a substance emits an unpleasant odor when reacted with water. It arises due to the formation, together with acetylene, of an insignificant amount of toxic gas vapors. Most often it is phosphine, hydrogen sulfide, and so on. This method is considered the most common, since it is possible to get acetylene from methane only using special equipment.
Receiving in the industry
How to get acetylene from methane in an industrial environment? Currently, only one method is used - cracking. In the process of producing acetylene , -C-C bonds are broken. This occurs in the presence of catalysts and when exposed to sufficiently high temperatures. For production methane is used - natural gas. These are inexpensive and readily available raw materials. For this reason, cracking is the most justified method both economically and technically.
How is cracking done?
There are several ways to carry out the methane - acetylene conversion. In the first case, natural gas is passed through pre-heated electrodes. In this case, the temperature can reach up to 1600 ° C. After heating, rapid cooling occurs. The second method is based on the use of heat, which is formed as a result of partial combustion of acetylene.
The equations of the methane - acetylene reactions are written as follows:
- In the I case: 2CH 4 = C 2 H 2 + 3H 2 .
- In the second case: 6CH 4 + 4O 2 = C 2 H 2 + 8H 2 + 3CO + CO 2 + 3H 2 O.
Experts do not recommend using cylinders equipped with bronze valves for storing acetylene. Indeed, the composition of this alloy includes copper. Since acetylene is chemically active, it can react with the metal. Explosive salts are formed as a result of this.
The use of acetylene
Acetylene is a substance that is widely used in various industrial sectors. Most often, this gas is used in the manufacture of ethyl alcohol as the main raw material. In addition, acetylene is used to produce certain types of rubber, acetic acid and plastic.
This gas is also actively used in welding operations, as well as in cutting various metals. It is worth noting that a strong flame is formed during the oxidation of acetylene by oxygen. Gas is a source of sufficiently bright light in autonomous type luminaires. Based on acetylene, explosives are produced , which are subsequently used as detonators.