Aromatic products of 340 °C supercritical-toluene extraction of two Turkish lignites: an n.m.r. study
✍ Scribed by Keith D. Bartle; Ayla Çalimli; Derry W. Jones; Raymond S. Matthews; Aral Olcay; Hooshang Pakdel; Taner Tuǧrul
- Publisher
- Elsevier Science
- Year
- 1979
- Tongue
- English
- Weight
- 598 KB
- Volume
- 58
- Category
- Article
- ISSN
- 0016-2361
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✦ Synopsis
Fractions of Elbistan and Seyitomer (Turkish) Iignites, extracted with supercritical toluene at 340°C and 8 MPa, have been separated by solvent extraction and silicagel 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 'Hdecoupled 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-0 in polar fractions. Narrow aromatic signals in 100 MHz ' H-n.m.r. spectra suggest the presence of singlearomatic-ring average structures. In the hexane-soluble aromatics, 27% (Elbistan) and 29% (Seyitomer) of the available sites are substituted by alkyl groups, some of which are at least eight carbon atoms long; the hexane-soluble polar and asphaltene/asphaltol fractions contain fewer such groups.