Aromatic Hydrocarbons


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
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 ?
The purpose of this contract is for asbestos detection and determination of polycyclic aromatic hydrocarbons (PAHs) on the asphalt roads of the county and the aggregate asphalt stocks available in formulas asphalt implemented.
The Belgian study may be the first showing polychlorinated aromatic hydrocarbons delaying puberty, says Marcia Herman-Giddens of the University of North Carolina at Chapel Hill.
Research done by Chevron and others clearly demonstrates that improved fuel cetane brings with it more air quality benefits than reduced aromatic hydrocarbon content by itself.
For instance, the discovery of the aryl hydrocarbon receptor (AhR) occurred as a direct result of the known toxicity of dioxin and polycyclic aromatic hydrocarbons.
Geological Survey studied carcinogens known as polycyclic aromatic hydrocarbons (PAHs) that had collected in reservoirs in six states.
Company's Viplex plasticizers are low-cost aromatic hydrocarbons derived from petroleum and used primarily in vinyl plastisols and organisols where color is not a factor.
The UNEP negotiators will not tackle the other four POPs slated for controls under UN/ECE--polycyclic aromatic hydrocarbons, chlordecone (kepone), hexabromobiphenyl, and lindane.
Kenflex line of resins is derived from formaldehyde condensation of aromatic hydrocarbons.
52 million contract from the National Cancer Institute (NCI) to synthesize selected chemical carcinogens, derivatives of polynuclear aromatic hydrocarbons (PAHs), and chemopreventive agents of interest to the cancer research community.
Scientists at CSIRO and UWA have been working to develop a tool to detect aromatic hydrocarbons (benzene, toluene, ethylbenzene, p-xylene and naphthalene) at very low concentration in aqueous solutions.
Zare still maintains, however, that polycyclic aromatic hydrocarbons (PAHs) found in the meteorite may have originated on Mars, regardless of the origin of amino acids.
Biodiesel emissions also reduce by 80 to 90 percent potential cancer-causing compounds called Polycyclic Aromatic Hydrocarbons (PAH) and nitrated PAH.