Structural characterization of the oligomeric constituents of petroleum pitches

摘要: Abstract The separation of petroleum pitch into its oligomeric fractions via dense-gas extraction (DGE), followed by the application both new and conventional analytical techniques to those fractions, has given us unique capabilities for identifying specific molecular structures that exist in pitches their concentration. Specifically, containing 98% monomer or 97% dimer were isolated DGE characterized using MALDI, MALDI-PSD, FD mass spectrometry (MS); 1 H NMR, UV–Vis, FT-IR spectroscopy. Results indicate weight distribution (MWD) fraction is approximately Gaussian, with dominant species being methylated derivatives polycyclic aromatic hydrocarbons (PAH) benzofluorene (216.4 m / z ), chrysene, (228.3 benzofluoranthene (252.3 isomers. methyl substituents per molecule also a maximum at 2. MWD most prevalent (  = 454.6, 468.7, 482.8) are consistent condensation reactions common an accompanying loss 4–6 hydrogens. As mesophase contain up 25% previously identified, herein proposed significant constituents pitch.