Coal aromaticity, definition

Fluoranthene (Called 1,2-benzo-acenaphthy-len or 1,8-o-phenylen-naphthylen in Ger), C16H10(Thought to be ClaH10in early literature), mw 202.24, colorless ndls, sp gr 1.158 at 20°, nD 1.739 at 20°, bp 393°, 217°(30mm Hg), mp 109.5-110.5°, sol In benz, chlf, eth, HAc hot ale. A tetracyclic fused ring aromatic hydrocarbon, this material is found in some coal tars. It forms definite complexes with many poly nitrated aromatics (Refs 1 to 6) Refs 1) Beil 5, 685, (340, 344), [609] 2276 2) J. vonBraun E. Anton, Ber... 

In ebullating bed reactor, such as the H-coal process, Ni-Mo or Co-Mo alumina catalysts have been used (96). The catalyst definitely improves the oil yields by accentuating aromatic hydrocracking, achieving conversions around 95% at catalyst make-up rates of 1 3%. 

The percentage of aromatic carbon can be determined now by solid state NMR. Extensive work in this area is reported in the literature (2, 4, 5). The other two questions cannot be answered definitively by solid state studies alone. One should mention the work of Friedel and Queiser (6) in which information on the degree of aromatic ring condensation was obtained by UV-visible spectroscopy on coal itself. They concluded that the degree of aromatic ring condensation is quite low in bituminous coals. 

The 14C data probe the number of introduced methyl groups and monitor subtle differences in the coal response toward systematic variations in the reaction conditions however, the data do not identify all of the sites of alkylation. To obtain more definitive structural information on the sites of alkylation, the CP/MAS 13C NMR spectra of the three samples derived from repetitive methylation with fluorenyllithium and [13,14C]H3I were measured. Three difference spectra were obtained 1 minus blank, 2 minus blank, and 3 minus blank, where the numbers refer to the treatment number, and the blank is the sample obtained from reaction of the O-methyl coal with fluorenyllithium followed by a water quench. As before, the nulling of the aromatic carbon envelopes is the subtraction criterion. 

CAS 8030-30-6 68920-06-9 64742-95-6 (It. aromatic) 977126-64-9 UN 1255 (DOT) UN 1256 (DOT) UN 1270 (DOT) UN 2553 (DOT) Synonyms Benzin Benzine Coal tar naphtha Coal tar naphtha distillate Heavy naphtha Hydrotreated naphtha Naphtha coal tar Naphtha, heavy Naphtha, hydrotreated Naphtha, petroleum Naphtha, solvent Petroleum benzin Petroleum-derived naphtha Petroleum distillates (naphtha) Petroleum ether Petroleum naphtha Petroleum oil Petroleum spirit VM P naphtha Definition Petroleum distillate... 

Thus, concepts of coal structure must also satisfy any of the relevant data from the variety of chemical manipulations of coal that have been described in a previous section and add positive knowledge about the nature of coal. In addition, a consensus of the aromaticity values reported would be that there appears to be a definite increase with rank. The values reported range from 40% to 50% for low-rank lignite and subbituminous coals to nearly 100% for anthracites. 

As with petroleum asphaltene (Speight, 2007), it is difficult (if not impossible) to accurately depict the structure of coal-derived asphaltene constituents. A simple assessment should include the statement small-ring polynuclear aromatic systems, basic and nonbasic nitrogen as well as phenolic and etheric oxygen. How these types enjoy an intramolecular existence is another matter which is difficult and whose definition is left to future research. 

The involvement of aromatic C - N<, especially derivatives from carbazoles, is not definite yet. Such a mechanism would be desired to reduce hydrogen consumption. HDO is not an important reaction for petroleum products, but it is very important in stabilizing coal-derived liquids. HDO of dibenzofuran is very slow. An acidic support is helpful for the HDO of dibenzofuran species. 

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