Aromatic Hydrocarbons


Also found in: Dictionary, Thesaurus, Medical.
Related to Aromatic Hydrocarbons: benzene

Aromatic Hydrocarbons

 

organic compounds of carbon and hydrogen, containing a benzene ring.

The simplest and most important representative of aromatic hydrocarbons is benzene (I) and such homologues as methylbenzene, or toluene (II), and dimethylbenzene, or xylene. Aromatic hydrocarbons also include derivatives of benzene with unsaturated side chains—for example, styrene (III). There are also many aromatic hydrocarbons having several benzene rings per molecule—for example, diphenylmethane (IV) and diphenyl C6H5—C6H5, in which both benzene rings are directly connected to one another; in naphthalene (V) both rings share two carbon atoms. These hydrocarbons are called aromatics with condensed rings.

The basic source of aromatics are products of coking coal. On the average, one ton of coal resin yields 3.5 kg of benzene, 1.5 kg of toluene, and 2 kg of naphthalene. Of great importance is the production of aromatics from liquid petroleum hydrocarbons. For certain aromatics purely synthetic methods are practical. Thus ethylbenzene, produced from benzene and ethylene, is condensed to yield styrene:

The chemical properties of aromatic hydrocarbons differ sharply from those of the unsaturated alicyclics. They are relegated to a separate large class of chemical compounds. When aromatic compounds are treated with sulfuric acid, nitric acid, halogen, and other reagents, hydrogen atoms are replaced, and aromatic sulfo acids, nitrogen compounds, and halogen benzenes are formed. These compounds serve as intermediary products in the manufacture of dyes and pharmaceuticals. Styrene easily forms the useful and important polymer polystyrene. During the oxidation of naphthalene, phthalic acid o-C6H4(COOH)2 is formed; it serves as a raw material in the production of many dyes, alkyd resins, and phenolphthalein.

REFERENCE

Iukel’son, I. I. Tekhnologiia osnovnogo organicheskogo sinteza. Moscow, 1968.

IA. F. KOMISSAROV

References in periodicals archive ?
Concentrations and source characterization of polycyclic aromatic hydrocarbons in pine needles from Korea, Mexico, and United States.
Sanz, "Fluorescence techniques for the determination of polycyclic aromatic hydrocarbons in marine environment: an overview," Analusis, vol.
Let [PAH.sub.n] be the general representation of Polycyclic Aromatic Hydrocarbons molecules for any positive integer n (see Figure 1).
Pollutants in Hong Kong soils: Polycyclic aromatic hydrocarbons. Chemosphere, 67(3), 464-473.
White, "An overview of immunotoxicology and carcinogenic polycyclic aromatic hydrocarbons," Environmental Carcinogenesis Reviews, vol.
Up till now, around 30 compounds and many other derivatives of polycyclic aromatic hydrocarbons have been discovered having carcinogenic and mutagenic properties which make them largest class of carcinogens ever known (Bjorseth and Ramdahl, 1985).
The concentration levels, spatial distributions of resolved aliphatics, total aromatic hydrocarbons in addition to unresolved complex mixture in surface sediment samples from Jeddah coast were detected.
In present study the hydrocarbon degrading bacterial strains were isolated from petrol contaminated soil of Karachi and the isolated bacterial strains were identified and checked for their biodegradation capabilities for aromatic hydrocarbons (xylene, phenanthrene, naphthalene, biphenyl and anthracene) which are deleterious for both biotic and abiotic flora by means of enumeration using spread plate method.
In general, saturated hydrocarbons are considered to discuss the origin and maturation of source rocks, while aromatic hydrocarbons are little taken into account to deal with thermal maturity [2-5], source of organic matter [6, 7], biodegradation [8, 9] and depositional environment [10].
An aromatic hydrocarbons production complex at Atyrau refinery will begin operation in the second half of 2014, said Kazakh Minister of Oil and Gas Uzakbay Karabalin on Monday.