Effect of light component on the regulation of quinoline insolubility in pitch during thermal treatment

Abstract Pitches with different contents of light component were obtained from the high‐temperature coal tar by distillation. The effect of the light component on the thermal polymerization of pitch was investigated using a laboratory autoclave. The component distribution in the original pitch was determined by gel permeation chromatography. The variation of carbon distribution in the modified pitch was monitored by solid‐state 13 C nuclear magnetic resonance. The results show that the variation of quinoline insolubility (QI) in the modified pitch during thermal treatment is markedly influenced by the amount of light component. When the light components exist in the original pitch, the QI in the modified pitch decreases at a low temperature (below 683 K) during the initial reaction stage and subsequently increases. The toluene insolubility of the modified pitch invariably increases. When the light components are added in the original pitch with a higher softening point, the results show the same trend of decrease of QI in the modified pitch. It can be included that the QI content in the modified pitch can be regulated by both the thermal polymerization conditions and the contents of the light component in the original pitch. Copyright © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.