Polar compounds consisting of acidic, basic and neutral nonhydrocarbons were separated from the oil portion derived from coal hydrogenation by means of liquid chromatography. These polar compounds comprised a substantial amount of the oil portion, up to ~60 wt%. Acidic and basic compounds were extracted subsequently by chemical methods, leaving the neutral nonhydrocarbons. The neutral nonhydrocarbons were derived further into eight subfractions, Fr-PP,-1 to -8, using gel permeation chromatography.
Thefractionswereanalysed quantitatively using 13C-and 'H-n.m.r.. Information on the distribution of functional groups containing heteroatoms, especially oxygen, which were present as phenolic, phenylether or heteroaromatic rings, was provided indirectly by 13C-n.m.r. spectra, utilizing the chemical shift of the carbon which can be distinguished by an adjacent oxygen. Simultaneous application of 13C-n.m.r. with 'H-n.m.r. reduced considerably the number of assumptions required for estimating the average molecular structure of polar compounds.
Combination of 13C-and 'H-n.m.r. spectroscopy for structural analyses: S. Yokoyama et al. * Not all aC, to the heteroatom of an aromatic ring resonate in the region between 148 and 178 ppm, for example, indole (a 140 ppm); however, most of these heteroaromatic ring carbons have resonance signals in this region.