Changes in the Characteristics of Pitch on Modifying Coal Tar by Ozone in Chloroform

The quality of coal tar pitch samples obtained from industrial coal tar and tar modified by means of ozone in chloroform is compared. The structure of the pitch is determined by means of standard chemical analysis of the pitch, IR and NMR spectroscopy, and elemental and thermogravimetric analysis. The ozonolytic modification of coal tar in a neutral solvent (chloroform) increases the yield of pitch, its content of the α fraction (the sum of the α1 and α2 fractions), the softening point, and the yield of volatiles.