Carlos A. Islas

The unusual properties of high mass materials from coal-derived liquids☆

Abstract This short paper highlights the unusual properties of the high-mass material of coal liquids isolated by their insolubility in pyridine and solubility in NMP. The separation has been achieved by a column chromatography method. One gram quantity have been processed and near quantitative recovery of the sample as fractions has been achieved. This fractionation permitted recourse to a broad range of analytical methods, including some (e.g. 13 C NMR), which require large sample sizes. Multiple macro analyses have been undertaken, using elemental analysis, TGA proximate analysis, NMR and FT-ir in addition to the micro-analytical methods used previously—pyrolysis-gc-ms, SEC, UV–fluorescence, probe-ms and MALDI-ms. The fractions show increasing concentrations of large molecular mass material with increasing polarity of successive eluents used in the fractionation. Evidence from solid-state 13 C NMR and UV–fluorescence spectroscopy show progressive structural changes with increasing apparent molecular mass.

CORRELATION OF PYROLYSIS-GAS CHROMATOGRAPHY MASS SPECTRA AND NUCLEAR MAGNETIC RESONANCE SPECTRA OF PITCH FRACTIONS SEPARATED BY PLANAR CHROMATOGRAPHY

A coal tar pitch from the high temperature coking of coal has been fractionated by planar chromatography into fractions immobile in pyridine, mobile in pyridine but not mobile in acetonitrile, and mobile in both solvents. Fractions have been examined by pyrolysis-gas chromatography/mass spectrometry at 770 and 1300 °C, and by nuclear magnetic resonance (NMR) methods (1H in solution and 13C (CPMAS TOSS) in the solid state). The fraction mobile in both solvents resembled the whole pitch in that the pyrolysis products were all polycyclic aromatics. The fraction mobile only in pyridine and the immobile fraction both gave alkene fragments as the most abundant pyrolysis products with polycyclic aromatics of low intensity only. The pyridine mobile and immobile fractions were shown by size exclusion chromatography with ultraviolet (UV) absorbance detection and by UV fluorescence spectroscopy to consist of large aromatic clusters and of large molecules. It is likely that the large aromatic clusters did not pyrolyse into fragments able to pass through the GC column. NMR methods confirmed the apparent trend of increasing aliphatic content with increasing immobility in thin layer chromatography. Copyright