Coal-tars phenanthrene

Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) that can be derived from coal tar. Phenanthrene is used in the production of dyes, pharmaceuticals, and explosives, and in biochemical research. A derivative, cyclopentenophenanthrene, has been used as a starting material for synthesizing bile acids, cholesterol, and other steroids. 

The pitch of coal tar is the black or dark brown amorphous residue that remains after the redistillation process. The volatiles contain a large quantity of lower molecular weight polycyclic hydrocarbons. As these hydrocarbons (naphthalene, fluo-rene, anthracene, acridine, phenanthrene) sublime into the air there is an increase of benzo(polycyclic hydrocarbons in the tar and in the fumes. Polycyclic hydrocarbons, known to be carcinogenic, are of this large molecular type. 

Two or more benzene rings fused together form a number of polycyclic benzenoid aromatic compounds, naphthalene, anthracene and phenanthrene, and their derivatives. All these hydrocarbons are obtained from coal tar. Naphthalene is the most abundant (5%) of all constituents of coal tar. 

The following is one of the methods employed for the separation of pure anthracene from the coal tar fraction containing it. Carbazole and phenanthrene are the chief impurities present. 

Anthracene oil heaviest distillable coal tar fraction, with distillation range 270-400°C (520-750°F), containing creosote oil, anthracene, phenanthrene, carbazole, and so on. 

Table XII presents compositional data for the aromatic hydrocarbons present in the anthracene oil. Compounds in the -12(H), -14(H), -18(H), and -22(H) series account for 78% of the aromatic hydrocarbons. The -12(H) compounds identified by GC/MS include naphthalene, 1- and 2-methylnaphthalene and at least 5 naphthalenes possessing 2 alkyl carbons. By GC/MS, acenaphthene and biphenyl account for 94% and 6%, respectively, of the first homolog in the -14(H) series. The parent member of the -18(H) series (C2.4H10 waS PreParat -ve -y isolated using GC and identified by UV and NMR to be >98% phenanthrene. The dominance of phenanthrene over anthracene in both high- and low- temperature coal tars has been previously noted (29,30,40,41,42,43). Thus, phenanthrene and presumably its alkylated homologs comprise the -18(H) Z series and account for 15.4% of the anthracene oil. The initial homolog in the -22(H) series, is comprised of 58%...

SYNS COAL TAR PITCH VOLATILES PHENANTHRENE PHENANTHREN (GERMAN) PHENANTRIN... 

Together with benzene and naphthalene two other hydrocarbons are obtained from coal tar though in much smaller amounts. They are anthracene and phenanthrene, both of which have the formula CuHjo. Anthracene together with phenanthrene is present in the coal tar distillate which boils above 270°. The yield of anthracene is about 0.25 to 0.45 per cent of the tar. The crude distillate is purified by a second distillation and separated into two fractions (i) A product known as 50 per cent anthracene which is crystalline and still contains phenanthrene. (2) A less volatile non-crystalline oil known as anthracene oil. The 50 per cent anthracene is largely used, just as it is without further purification, in the preparation of alizarin, itsmost important derivative. To obtain pure anthracene from the crude 50 per cent product it is first redistilled after addition of potassium carbonate which forms a non-volatile compound with a constituent known as carbazole. 

The third hydrocarbon consisting of condensed benzene nuclei similar to naphthalene and anthracene is known as phenanthrene. It has the composition C14H10 and is thus isomeric with anthracene. It is found associated with the latter in the coal tar distillate boiling above 270° and is separated by solution in carbon disulphide (p. 793). It is a solid crystallizing in colorless flakes, m.p. 99°, b.p. 340°. It is only slightly soluble in water, a little more soluble in alcohol and soluble in ether. 

Anthracene and phenanthrene are stereoisomers that are crystals in pure form. Anthracene is a pale yellow crystal, while phenanthrene exhibits a yellow to brown hue. Besides its common name, anthracene is referred to as anthracin, green oil, or paranaphthalene. The compound is commercially produced by recovery from the coal tar distillation fraction known as anthracene oil or green oil. Anthracene is the key ingredient in the production of anthraquinone. However, it and phenanthrene are also used for the manufacture of dyes, fibers, plastics, and wood preservatives. ° Phenanthrene, also known as phenanthrin, can be produced by high-temperature fractional distillation of coal tar oil. It is additionally used for the oxidation of diphenic acid for use in polymers, as well as the production of chemical softeners, explosives, and some pharma-ceuticals. Recent research has extended the application of both isomers to scintillation counters, semiconductors, and photoconductors. ... 

The levels, either in concentration or percent weight, in which several PAHs appear in various other substances are given below. A coal tar sample has been found to contain approximately 0.007 mg/kg benz[a]anthracene, 3 mg/kg benzo[b]fluoranthene. 4 g/kg chrysene, and 30 mg/kg benzo[a]pyrene (Perwak et al. 1982). High-temperature coal tar contains 1,000 mg/kg dibenz[a,h]anthracene (lARC 1985). A sample of coal tar pitch was found to contain <10 mg/kg benz[a]anthracene, <10 mg/kg chrysene, and approximately 10 mg/kg benzo[a]pyrene creosote oil contains <3 mg/kg benz[a]anthracene, <1 mg/kg chrysene, and <10 mg/kg benzo[a]pyrene (Perwak et al. 1982). Creosote has been reported to contain 21% phenanthrene. 10% fluorene, 10% fluoranthene. 9% acenaphthene. 8.5% pyrene. 3% chrysene. 3% naphthalene, and 2% anthracene (Lorenz and Gjovik 1972). 

PAH concentrations in a variety of other media have been evaluated. PAH concentrations in fly ash and bottom ash samples from domestic municipal incinerators ranged from not detected to 7.400 p g/kg. with phenanthrene the most abundant and frequently detected compound (Shane et al. 1990). Machado et al. (1993) reported the total concentrations of 16 PAHs (all PAHs in this profile except benzo[a]pyrene) in asphalt and coal tar pitch to be 50,122 and 294,300 ppm (pg/g), respectively benzo[a]pyrene concentrations were <6 and 18,100 ppm, respectively. The concentrations of benzo[a]pyrene (250-480 ppm) and several other PAHs in coal tar fumes were higher than those in asphalt fumes by two to three orders of magnitude. The PAH content of asphalt and coal tar pitch fumes increased with increasing generation temperature. 

Naphthalene, anthracene, and phenanthrene are the three simplest members of this class. They are all present in coal tar, a mixture of organic substances formed when coal is converted to coke by heating at high temperatures (about 1000°C) in the absence of air. Naphthalene is bicyclic (has two rings), and its two benzene rings share a common side. Anthracene and phenanthrene are both tricyclic aromatic hydrocarbons. Anthracene... 

Early methods of separation employed such solvents as oleic acid/ crude coal-tar solvent naphtha, light pyridine,5 etc. Based on the selective solution of phenanthrene by the coal-tar naphtha, and of carbazole liy the light pyridine, Clark proposed a complicated scheme for the separation and recovery of all three of these constituents. Recently, organic liquid compounds containing the furan nucleus have been found to have a highly selective solvent action on phenanthrene and carbazole." Thns, furfural while dissolving phenanthrene and carbazole does not have a marked solvent action on anthracene at low temperatures. However, at elevated temperatures it does dissolve anthracene with the result that it is possible... 

If recovery of the carbazole is not desired it may be quite readily removed from the autliraccne-phenanthrene portion of the crude by reaction with caustic alkali or potash. The crude anthracene may be dissolved in aliphatic or aromatic organic bases sudi as-pyridine, quinoline or the bases obtained from coal-tar, an equivalent amount of potassium hydroxide to read with the carbazole added, and the purified anthracene separated by cooling and filtering.7 Heating to 160° to 170° C. is used to insure complete solution of the materials and to increase the reaction of the alkali with the carbazole. Ordinarily, simple fusion with caustic has been found to be sufficiently effective to remove the carbazole. Carbazole forms a C0H4v... 

Coal Tar Products. The presence of coal tar creosote metabolites in the urine of humans and rabbits receiving calcium creosote (a calcium salt of creosote) tablets was evidence that this salt of creosote was absorbed following ingestion (Fellows 1937, 1939b). Furthermore, evidence exists that certain PAHs found in coal tar creosote such as anthracene (Rahman et al. 1986), benzo[a]pyrene (Hecht et al. 1979 Rahman et al. 1986 Rees et al. 1971 Yamazaki et al. 1987), chrysene (Chang 1943 Modica et al. 1983), and phenanthrene (Rahman et al. 1986) are absorbed following oral administration in animals. 

Another study of metabolites of coal tar volatiles was carried out by Grimmer et al. (1997). Urine samples were collected from workers at a coke plant over a period of four days. Two workers were exposed to high levels of PAH and two were exposed to lower levels. The concentration of metabolites of phenanthrene, fluoranthene, pyrene, chrysene, and benzo[a]pyrene (in total, about 25 compounds) in urine were measured by GC/MS. The urinary metabolite profile for each individual remained similar over the four days analyzed. However, there was a significant difference between individuals for the... 

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... 

On a hot, sunny day evaporation of creosote from the surface of treated wood may release coal tar creosote constituents to the atmosphere. Only the volatile creosote components such as acenaphthene and naphthalene will volatilize the heavier fractions will remain on the wood (E1SDA 1980). Volatilization may also be greater during warmer months when ambient temperatures are higher. Gevao and Jones (1998) observed greater volatilization of acenaphthene, fluorene, phenanthrene, anthracene, and fluoranthene from creosote-treated wood at 30 °C than at 4 °C. 

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