Structural Evaluation of Coal Tar Pitch by Multiple Techniques

Abstract

Coal tar pitch (CTP) is an important heavy carbon resource. Its effective utilization largely depends on the full structural evaluation of CTP. In this paper, the CTP from Shanxi Datuhe coal tar distillation plant was adopted as the sample (DCTP). Multiple analytical equipments including X-ray diffractometer spectrometer, solid-state 13C nuclear magnetic resonance spectrometer, and X-ray photoelectron spectrometer were used to directly characterize DCTP, and DCTP was further catalytically oxidized over ruthenium ion. The typical characteristics of structures in DCTP were investigated by combining the two methods. It was demonstrated that aromatic structures dominated in DCTP, in which the aromaticity was up to 95 %. Specifically, aromatic structures were abundant in peri-condensed aromatic structures, poor in cata-condensed aromatic structures, but short of polyaryl structures. There were about 4 rings in each aromatic cluster, and the aromatic clusters were lowly substituted by a few methyl side chains. Furthermore, the nitrogen and sulfur atoms mainly existed in the heterocyclic ring, while the oxygen one was principally in Car‒O group.