Production of Isotropic Coke from Shale: Composition of Oxidation Products from Shale-Tar Distillation Residues

Abstract

The influence of thermal oxidation on the mesogenic properties of the atmospheric-distillation residue of shale tar was considered in a previous article [1]. It was found that thermal oxidation depresses the mesogenic properties of the (α + β) fraction but boosts the mesogenic properties of the γ fraction. In the present work, attention focuses on the change in structural and group (fractional) composition of the atmospheric-distillation residue and its individual components in the course of thermal oxidation, in terms of the impact on the mesogenic properties. Thermal oxidation decreases the hydrogen content in the atmospheric-distillation residue and increases the aromatic content of its γ fraction. For the (α + β) fraction, the increase in aromatic content is considerable only for high-temperature oxidation. In addition, decrease in the content of aliphatic hydrogen is observed primarily in α positions with respect to the aromatic rings and double bonds. For the γ fraction, the change in the proportion of aromatic hydrogen in the course of thermal oxidation is analogous to the change in mean size of the structural elements described in [1]. In this paper the next denotations are made: isooctane-soluble fraction is denoted as γ fraction, isooctane-insoluble-toluene-soluble is denoted as β fraction, toluene-insoluble-quinoline-soluble is denoted as α fraction, the fraction insoluble in quinoline, pyridine and carbon disulfide is denoted as α1 fraction.