Aromatics (otherwise called arenes) - biosoedineniya are organic molecules which contain one or more cycles with six atoms Carbo.The benzene ring, characterized by unique physical and chemical properties.The name "Arena" became the organic and general chemistry in the late 18th - early 19th century.These include substances that are composed of two chemical compounds - Hydrogen and carbon and have a pleasant smell (resins, balsams, essential oils, incense).Over time, the name "aromatic hydrocarbons" lost its importance, as the aromatic substances are found among other classes of organic compounds, and most aromatic or have an unpleasant odor.Benzene was isolated for the first time in the early 19th century from the coal gas.Later (1845) AFHoffmann allocates aromatic hydrocarbons (benzene) from coal tar.Nowadays Class Arena (IUPAC classification) combines compounds based on molecules that have benzelnye core.So that such compounds are separated into single and multi-ring, as well as aromatic hydrocarbons with condensed nuclei.Mononuclear
arena - are organic compounds containing one benzene ring.The structure of the benzene molecule, a typical representative of arenes often demonstrated Kekule formula in the form of a cycle of six atoms of carbon fiber, which in turn are associated with simple CC and C = C double bonds.This structure was confirmed by modern physical and chemical analysis.
Main Kekule representation of the structure of benzene are: 1) benzene has a hexagonal ring structure;2) benzelnom ring esti three simple and three double bonds;3) All six of Carbo atoms on the benzene ring are equal to each other.The formula shows the elemental composition of benzene, the ratio of atoms of carbon and Hydrogen in the molecule, the absence of the isomers of monosubstituted benzene derivatives.
Aromatic hydrocarbons are quite common in nature.They are part of coal tar that is obtained after dry distillation of coal.Arena are part of many types of crude oil and other natural products (resins, balsams, etc.).During the dry distillation of coal on average, about three percent of coal tar or coal tar.And from coal tar by fractional distillation a series of fractions: a light oil (comprises xylenes, toluene, benzene, thiophene), carbolic oil (contains cresols, phenols and naphthalene), creosote oil (containing naphthalene) anthracene oil (contains phenanthrene, anthracene, andother higher arenas), and pitch that is used for road paving and as a construction material.
The use of aromatic hydrocarbons.Benzene is characterized by a specific odor, practically insoluble in water.It is a good solvent for organic biosoedineny.Synthesized from coal tar.Benzene - a valuable raw material for the production of dyes, medicines, explosives, plant growth stimulants, herbicides, insecticides, etc.
Toluene is readily soluble in organic solvents.Prepared from coal tar, as well as certain grades of oil.Synthesized from toluene benzene alcohol, benzaldehyde, benzoic acid, dyes, medicines, saccharin, trinitrotoluene.
xylitol are good organic solvents.Prepared from coal oil, as well as by fractional distillation of coal tar.From xylenes synthesized phthalic anhydride, xylene, artificial polyester fiber.Sometimes xylenes is added to gasoline.
