Composition of anthracene oil

The composition of anthracene oil is dominated by parent aromatic compounds possessing 2, 3, and 4 aromatic rings. 

For example, Beynon and Cwm coals when digested in anthracene oil give extraction yields of 68% and 47% respectively. This variation can be explained by reference to the maceral composition of the coals. Beynon coal contains a lower concentration of inertinite than the Cwm coal (Table V). In experiments where relatively pure samples of petrographic species were digested in anthracene oil, exinite and vitrinite were shown to be highly soluble, whilst in comparison the inertinite was almost completely insoluble. Similar variations in reactivity of macerals have been reported from studies of solubility in pure organic solvents (1(3). 

A system of classifying coals for solvent extraction, based upon the extent of extraction when using anthracene oil and phenanthrene as solvents has been developed. The reactivity of the coals can be conveniently presented by superimposing the results on Seyler s coal chart. The effects of variations in maceral composition are also discussed. 

Some methane is manufactured hv the distillation of coal. Coal is a combustible nick formed from the remains of decayed vegetation. Ii is ihe only rock containing significant amounls of carbon. The elemental composition of coal varies between 60% and 95% carbon. Coal also contains hydrogen and oxygen, with small concentrations of nitrogen, chlorine, sulfur, and several metals. Coals are classified by the amount of volatile material they contain, that is. by how much of Ihe mass is vaporized when the coal is healed to about 900 C in the absence of air. Coal that contains more than 15% volatile material is called bituminous coal. Substances released from bituminous coal when it is distilled, in addition to methane, include water, carbon dioxide, ammonia, benzene, toluene, naphthalene, and anthracene In addition, the distillation also yields oils, tars, and sulfur-containing products. The non-volatile component of coal, which remains after distillation, is coke. Coke is almost pure carbon and is an excellent fuel, However, it may contain metals, such as arsenic and lead, which can he serious pollutants if ihe combustion products are released into the atmosphere. 

Chemical Composition of Raw and Upgraded Anthracene Oil and the Chemistry of Coal-Liquids Upgrading... 

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%...

The compositional data for the aromatic hydrocarbons present in the upgraded anthracene oil are presented in Table XIII. Comparison of the data in Tables XII and XIII reveals significant increases and decreases in the amounts of hydroaromatic and aromatic hydrocarbons, respectively, under all reaction conditions. This is especially evident by the presence and absence of the hydroaromatic -10(H) series in the products and feeds, respectively, and by the large increase in the weight percentage of the -8(H) compounds in the products compared to the feeds. The presence of significant amounts of dihydro-, tetrahydro-, and octahydrophenanthrenes in the products is indicated by GC/MS, by the increase in the weight percents at C-14 in the -16(H) and -14(H) series, and by the presence of C- H g, -10(H). 

Therefore, data of this type have been used to support the concept of a more uniform composition for coals and are further supported by a study of extraction of coals with anthracene oil at 350°C (660°F) in which the H/C atomic ratio of undissolved residue was observed to remain remarkably constant up to 80% extraction. Furthermore, the infrared spectra of extracts from coals in the range 78%-89% carbon resemble those of the parent coals. 

The creosote fraction of coal tar has a variable composition (Table 13.11) and may contain specific chemical compounds that can be isolated for commercial use. For example, when creosote oil is cooled, a solid referred to as anthracene cake may separate and consists primarily of anthracene, carbazole, and phenanthrene (Table 13.12). 

A broad application involves composites made up of polysulfide oligomers and products of carbochemistry origin—coke plant, pitcoal tar, anthracenic oil, pitch, bimm, and tar. These composites are economical and are used in the building industry [68]. 

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