Polycyclic aromatic hydrocarbons brown coal

The polycyclic aromatic hydrocarbons (PAHs) in brown coal consist predominantly of pentacyclic angularly condensed hydroaromatic moieties. These compounds appear to be derived from C30 triterpenoid... 

Chaffee A.L., Johns R.B. (1983) Polycyclic aromatic hydrocarbons in Australian coals. I. Angularly fused pentacyclic tri-and tetra-aromatic components ofVictorian brown coal. Geochim. Cosmochim.Acta 47, 2141—55. 

Usually, coal tars are viscous liquids or semisolids that are black or dark brown with a naphthalene-like odor. Coal tars are complex combinations of polycyclic aromatic hydrocarbons (PAHs), phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. PAH composition of coal tars is variable. 

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Physically, they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. The coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. The coal tar creosotes consist of aromatic hydrocarbons, anthracene, naphthalene, and phenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, dark brown to black residue which contains polycyclic aromatic hydrocarbons and their methyl and polymethyl derivatives, as well as heteronuclear compounds... 

Coal tar creosote consists of aromatic hydrocarbons, anthracene, naphthalene, andphenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, daik brown to black residue that contains PAHs and their methyl and polymethyl derivatives, as well as heteronuclear compounds. 

Coal tar is black or dark brown-colored liquid or a high-viscosity semisolid that is one of the byproducts formed when coal is carbonized (Chapter 16). Coal tars are complex and variable mixtures of polycyclic aromatic hydrocarbons (PAHs), phenols, and heterocyclic compounds. Because of its flammable composition coal, tar is often used for fire boilers, in order to create heat. Before any heavy oil flows easily, they must be heated. 

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