Abstract
vacuum residue (IL-S3) of Illinois No.6 coal from NEDOL coal liquefaction process was analyzed by 13C-NMR, FT-IR, and pyrolysis GC-MS. The IL-S3, was separated into two soluble fractions, HS (31.8%) and HI/PS (54.4%, ash free basis). The FT-IR analyses of the raw coal, the residue, and two soluble fractions of IL-S3 indicated that the residue and its soluble fractions have much more amount of aromatic hydrogen and less amount of hydroxyl groups. From absorption at 3150-3000 and 2700-3000cm-1, we could estimate the ratio of aromatic (Har) to aliphatic hydrogen (Hal) contained in IL-S3 and its HI/PS fraction. The 13C-NMR spectra of the raw coal, the IL-S3, and the soluble fractions revealed that carbon aromaticity (fa) of the residue and two soluble fractions was a little higher than that of raw coal while the number of carbon atoms attached to oxygen (CH3O and Ar-O) of the residue was lower than that of the raw coal. Curie-point pyrolysis GC of the residue showed the presence of phenanthrene, pyrene and chrysene and their monomethylated derivatives in it, while the pyrolysis of the raw coal gave aliphatic hydrocarbons, alkylbenzenes (-C4), alkylphe-nols (-C3), and alkylnaphthalenes (-C4). These results strongly suggest that deal-kylation, deoxygenation, and condensation of aromatic hydrocarbons took place during the NEDOL coal liquefaction process.
