AROMATIC PRODUCTS OF 340-DEGREES-C SUPERCRITICAL TOLUENE EXTRACTION OF 2 TURKISH LIGNITES - NMR-STUDY

Fractions of Elbistan and Seyitomer (Turkish) lignites, extracted with supercritical toluene at 340 °C and 8 MPa, have been separated by solvent extraction and silica-gel chromatography. Analyses by n.m.r. and i.r. spectroscopies and other methods have been combined in structural-analysis schemes to yield information about the average molecule in aromatic extracts. Carbon aromaticities, fa, derived from 22.63 MHz 1H-decoupled pulse Fourier-transform (PFT) 13C-n.m.r. are more widely spread for Elbistan (0.34-0.56) than for Seyitomer (0.40-0.43), and are lower than for supercritical-gas (SCG) products from bituminous coals. 13C-n.m.r. also reveals the presence of aromatic ether-O in polar fractions. Narrow aromatic signals in 100 MHz 1H-n.m.r. spectra suggest the presence of single-aromatic-ring average structures. In the hexane-soluble aromatics, 27% (Elbistan) and 29% (Seyitomer) of the available sites are substituted by alkyI groups, some of which are at least eight carbon atoms long; the hexane-soluble polar and asphaltene/asphaltol fractions contain fewer such groups. © 1979.