There are several industrial and laboratory methods for producing benzene which differ according to the kind of product selected as a starting material.The modern chemical industry as such, more and more uses various aromatic compounds, such as coke oven gas produced during the coking of coal.It is widely used coal tar and various factions formed during distillation of crude oil.
Coking coal - the most important process step in the industry, it is necessary to produce coke.There is no need to describe in detail all the technology, which is based on the production of benzene, suffice it to say that in this case it is formed at a time when coal is decomposed, and the decomposition products are coke and volatiles, primarily - coke oven gas.Its vapor is coal tar.When this gas passes through the system of capacitors is separated substances constituting it.After elektrofiltrovaniya coke gas already contains the vapors of organic compounds including benzene.Such receipt of benzene provides its output raw roughly equal to 10-11 kilograms per tonne of dry coal.
Coal tar also allows you to get the benzene.The technology here is reminiscent of the way in which is conducted to obtain benzene from coke oven gas.The fact itself that coal tar - rather complex composition component mixture of different kinds of aromatic organic compounds.Moreover, even at the present day, the composition of this compound has not been studied up to the end, and thus established the presence of more than 500 (!) Component.Processing technology is a process of two-stage separation into individual fractions of resin.For this purpose each of them is subjected to the action of alkali to remove the acid side.As a result of the formation of solid fractions - anthracene and naphthalene, as well as the lungs, which include and benzene.
common in the industry to obtain benzene in raw form, so-called crude benzene.To obtain pure compound, crude benzene must be cleaned from sulfur compounds.In this process, two phases are distinguished.The first occurs proper cleaning of sulfur impurities, and the second separated mixture purified by distillation.One of the products of this separation will be benzene.
most important source of various aromatic compounds is oil.That is why a modern benzene production is focused on the product.
There are also benzene from acetylene.This material under normal conditions is a gas, it is colorless, practically insoluble in water, is lighter than air.Among the chemical properties of the gas has the ability to polymerize, and therefore used in industry for producing benzene from acetylene.This method seems to be more promising in terms of creating and maintaining the conditions of the chemical reaction.The fact that acetylene, in itself, very explosive, because its use in industry connected with the necessity of strict observance of technological discipline and special equipment, especially heat resistance.At the same time, before acetylene, benzene prepared from sufficient to achieve a temperature of 400 C and hold it in the presence of graphite.This method was proposed in 1866 by French chemist M. Berthelot, however, the yield of substance was extremely small.Therefore, today's technology is widespread use of various types of catalysts, and for accelerating the reaction and increasing the yield of pure benzene.
In vitro benzene, as a rule, do not get, but if you still need arises, then use the method of fusing the benzoic acid with an alkali.The result of this reaction is benzene.
