Mesophase from electrode‐binder coal‐tar pitch: An appraisal of structural techniques

Abstract

AbstractAn electrode‐binder coal‐tar pitch containing mesophase and resulting from combined mild thermal treatment under nitrogen and hot filtration (to remove ash, etc.) has been examined by solvent analysis and magnetic resonance (high‐resolution 1H‐nuclear‐magnetic and electron‐spin resonance) spectroscopy, X‐ray diffraction and polarised light microscopy. At ambient temperature, residues and filtrates with higher mesophase contents tend to exhibit higher concentrations of unpaired electrons and higher stacks in crystalline regions. Room‐temperature 100 MHz 1H‐n.m.r. spectra of solvent extracts of the treated pitch fractions confirm the predominance of aromatic over aliphatic hydrogen in all samples; heat‐treated samples have lower content of hydrogen α to the rings but greater amounts of methylene and methyl hydrogen more remote from the rings than before the heat treatment.