QUANTITATIVE C-13 NMR-SPECTROSCOPY OF A COAL-DERIVED OIL AND THE ASSIGNMENT OF CHEMICAL-SHIFTS

The conditions necessary for the recording of quantitative 13C nuclear magnetic resonance spectra of the hexane-soluble oil separated from a coal hydrogenation product have been investigated. Measured values of T1 for different signals in the spectrum were less than 1 s, and altering the pulse-repetition time beyond 2-4 s had little effect on carbon aromaticities. The nuclear Overhauser effect was suppressed by gating the proton decoupling. Assignments of chemical shifts for various signals in the spectrum of the oil were made by reference to literature spectra of polyaromatic substances and their derivatives. Determinations of different structural carbon types were internally consistent. © 1979.