Anthracene-derived pitch

Figure 3. Molecular weight distribution of anthracene-derived pitch as measured by GPC, with quinoline as the solvent.

Chart 11. Proposed structures for some of the oligomeric molecular species identified by FDMS in anthracene-derived pitch. (Reproduced with permission from reference 4. Copyright 1980 Pergamon Press.)... 

Chart 111. Proposed structures for rearrangement products identified by FDMS in anthracene-derived pitch. 

Figure 8. Spin concentrations (spins gram) as a function of heat treatment temperature for anthracene- and naphthalene-derived pitches. Key o, anthracene-derived pitch , naphthalene-derived pitch.

The mass spectrum of naphthalene-derived pitch is shown in Figure 7. As with anthracene pitch, the spectrum is complex, but a detailed analysis shows the pitch to be largely composed of oligomeric species. Various species presumed to arise through bond cleavage and molecular rearrangement are also evident (21). Proposed structures for some major components are presented in Chart IV. Further heat treatment of the naphthalene pitch to... 

Lewis [86] found that naphthalene (I) and anthracene (II) derived pitches are complex mixtures of 2-10 units of the starting material and are only partly condensed, represented by the average structures ... 

A number of years ago. coal tar was the primary, if not the sole, source lor hundreds of important organic chemicals and derivatives, notably the phenols, cresols, naphthalene, and anthracene, as well as other important coal lar end-prralucls, such as solvent naphtha and pitch. In recent years, synthetic processes Tor the production of phenol, the cresols and later the xylcnols. have been developed and thus, to a large extent, have pushed coal lar into the background as a source of feedstocks for (he chemical industry. 

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. 

Edwards et al. [51] developed a solvent-free sample preparation method for carbonaceous pitches derived from anthracene and petroleum. A high molecular weight fraction of a petroleum pitch gave a LD mass spectrum with maximum ion intensity at about ni/z 900 and extended to an upper mass of at least m/z 2000. 

Berkovich (2003) uses the anthracene oil derived from coal as a solvent for pitch extraction under moderate temperature (425°C) and pressure. Sulfur and ash are very low. The cost of the process as a means of production of electrochemical fuel has not been estimated. 

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