Coal is a fossil fuel.It was formed back in the prehistoric era of the dead remains of plants through complex biochemical transformations.The coal contains both organic and inorganic components.
Coal was the first raw material in the production of organic materials.In its dry distillation, also called carbonization or pyrolysis gave aromatic hydrocarbons and their derivatives.The last formed the basis for the synthesis of organic dyes.However, coal as a source of chemical raw materials gradually gave way to a dominant position of oil and natural gas, of which now receive more than 90% of all organic compounds.Branch of science that studies the oil and gas and refining, petrochemicals called.
during dry distillation of coal, ie,when heated to high temperatures without oxygen obtained complex mixture of gaseous, liquid and solid products.
The gas-phase product - a coke oven gas containing mainly hydrogen and methane.The liquid product of pyrolysis - tar, which has channeled over 300 compounds: cresols, phenol, pyridine, anthracene, naphthalene, thiophene, 1,3-cyclopentadiene and others.Coke - the solid residue distillation is used in the industrial production of iron, the water gas and acetylene.
Water gas or a mixture of carbon oxide (II) and hydrogen, is prepared by reacting hot coke with steam: C + H2O = CO + H2.The reaction takes place by heating to 1000˚C.A similar mixture can be obtained by the catalytic decomposition of methane with steam: CH4 + H2O = 3H2 + CO (Ni, 700-900˚C).This mixture is synthesized many valuable products, particularly methanol: CO + 2H2 = CH3OH.The latter reaction is reversible in the presence of catalysts is pressurized to 250 atm.
Given the rapidly growing demand for organic chemicals obtaining them from the products of the dry distillation of coal is gradually losing value, yielding more and more a place of petrochemical production.For example, naphthalene, obtained from the coal before now are advantageously prepared from crude oil.However, coal retains its role as the main source of coke.It assumes that the value of these raw materials will increase in the near future, because the reserves of coal is considerably greater than the oil.Problems of its catalytic hydrogenation to obtain the fuel does not lose its relevance.