The structure of the carbon disulfide extract of vitrain-rich Pittsburgh coal (HVAB-82.6 percent c) was studied by various spectral techniques. The carbon disulfide-soluble material, which represented approximately 4 percent of the original coal, was obtained by extracting the coal with pyridine followed by extraction of the pyridine-soluble material with carbon disulfide. Both the pyridine and the carbon disulfide extracts were studied by ultraviolet-visible and infrared spectrophotometry and by electron and proton magnetic resonance. The carbon-13 magnetic spectrum of the carbon disulfide extract was also obtained. This represents the first application of this relatively new spectral technique to a coal extract and permitted direct measure of the aromaticity. The mean structural unit in the carbon disulfide extract was found to consist of two to three polynuclear condensed aromatic rings, with 0.4 Of the available aromatic edge carbons bearing alkyl, phenolic, and/or naphthenic groups.
Fuel, V. 47, No. 6, PP. 487-498