Acetylene – the most ordinary representative of a class of alkynes, i.e. the hydrocarbons having threefold communication in the molecule. Its chemical formula C2H2. It is colourless gas, it is easier than air, very explosive and chemically active. Store acetylene in steel sealed containers, it is better – with charcoal.
1. The easiest way of receiving acetylene – reaction carbide calcium with water. For certain many children remember how threw carbide pieces into pools. Immediately rough hissing began, and carbide literally "thawed" in the formed penalty fee. This reaction goes as follows: SaS2 + 2H2O = C2H2 + Sa (IT) 2
2. If the technical carbide polluted by impurity is used, reaction is followed by an unpleasant smell because of education along with acetylene of small amounts of poisonous gases of hydrogen sulfide, phosphene, etc.
3. Now the main industrial method of receiving acetylene – cracking (a rupture of communications - C-C-under the influence of high temperatures and in the presence of catalysts) natural gas of methane. It is most reasonable economically and technologically in view of availability of readily available and inexpensive raw materials. It is carried out in two ways: or the admission of methane through the heated electrodes (temperature of reactionary volume about 1600 degrees), with the subsequent fast cooling, or with use of heat which is formed at partial combustion of acetylene.
4. In the first case the reaction goes thus: 2CH4 = C2H2 + 3N2Vo the second case: 6CH4 + 4O2 = C2H2 + 8H2 + 3CO + CO2 + 3H2O