In order to obtain acetylene from methane, it is necessary to conduct a dehydrogenation reaction. Before proceeding to its consideration, we analyze some of the features of hydrocarbon.
Acetylene Characterization
This is a gaseous substance, which is the first representative of the class of unsaturated hydrocarbons (alkynes). It is lighter than air, poorly soluble in water. The molecular formula C 2 H 2 common to the entire class of SpN 2 p-2. Acetylene is considered an active chemical, and also very explosive. In order to avoid emergencies, it is stored in sealed steel containers, adding charcoal to it.
Getting from alkanes
Upon decomposition of methane, acetylene was obtained. This chemical reaction is carried out using a catalyst, occurs at elevated temperature. The starting material is the first representative of the paraffin class. During dehydrogenation, in addition to acetylene, hydrogen is formed.
Answering the question of how to obtain acetylene from methane, we represent the reaction equation in the form:
2CH4 = C2H2 + 3H2
Carbide method
You can get acetylene from methane or take calcium carbide as the starting material . The process proceeds under normal conditions. When calcium carbide interacts with water, not only acetylene is formed, but also calcium hydroxide (hydrated lime). Signs of a chemical process will be gas evolution (hissing), as well as a discoloration of the solution when phenolphthalein is added to a raspberry color.
When technical carbide, having various impurities, is used as the starting material, an unpleasant odor is observed during the interaction. It is explained by the presence in the reaction products of such toxic gaseous substances as phosphine, hydrogen sulfide.
Oil cracking
Currently, it is possible not only to obtain acetylene from methane. The main industrial method for the production of this representative of alkynes is the cracking (splitting) of hydrocarbons. If acetylene is obtained from methane, then energy costs will be minimal. In addition to inexpensive and affordable raw materials, this technology attracts hydrocarbon producers by the simplicity of technological equipment used in the methane dehydrogenation process.
There are two options for carrying out such a chemical process. The first method is based on passing methane through electrodes heated to 1600 degrees Celsius. The technology involves a sharp cooling of the resulting product. The second variant of methane dehydrogenation to produce acetylene involves the use of energy, which is generated by the partial combustion of this alkyn.
Cylinders containing acetylene cannot be equipped with bronze valves, since bronze contains copper. The interaction of this metal with acetylene is accompanied by the production of explosive salts.
Conclusion
Acetylene is currently used in various industrial fields. It is a valuable raw material for the synthesis of ethanol, plastics, rubbers, acetic acid. This representative of the class of alkynes is in demand in the cutting and welding of metals, as bright light in individual lamps.
The synthesis of explosives used in the form of detonators is carried out on the basis of acetylene. In the oxidation reaction of this alkyne in air oxygen, a strong flame is observed. Methane has no less value in the chemical industry. In addition to using it as a starting material for the production of acetylene, it is consumed in large quantities as a natural hydrocarbon in the fuel industry. When it is burned, a significant amount of heat is released.