INVESTIGATION OF RETROGRESSIVE REACTIONS LEADING TO THE CARBONIZATION OF SOLVENT-REFINED COAL

The carbonization of solvent-refined coal (SRC) samples produced by the liquefaction of an HVc bituminous coal has been studied. Carbonization conditions were 450 °C, 34.4 MPa, for 1 and 5 h hold times. The original SRCs and pyridine-insoluble fractions of the carbonization products have been characterized by Fourier-transform infrared spectroscopy. Spectral changes demonstrate that the formation of larger molecules during carbonization involve the joining together of aromatic molecules that were originally present, without increasing their size significantly. This is accomplished by the elimination of methylene units and condensation of phenolic functional groups originally present on the aromatic groups in the SRCs. © 1979.