Composition and Structural Characterization of the Extractive Pitches as Compared with the Commercial Reference Pitches of Different Origins

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The chemical and group composition, the empirical properties and the molecular structural characteristics of the extractive pitches produced by thermal dissolution of three medium-ranked coals were studied in comparison with the reference commercial pitches including typical coal-tar pitch, petroleum-derived pitch and the pitch sample derived from the blended mixture of coal tar with petroleum feedstock. The structural parameters of the average pitch molecules have been compared based on the 1H and 13C NMR spectra. It was shown that, in terms of chemical composition and empirical properties including carcinogen content, the extractive pitches resemble blended pitch sample, the structural parameters being close to commercial coaltar pitch sample. The average pitch molecule of extractive pitches was composed of predominantly aromatic nuclei with rather pericondensed structure

Thermal Dissolution of Coking Coals in the Anthracene Fraction of Coal Tar

The thermal dissolution of two samples of 1GZhR and ZhR coal in the anthracene fraction of coal tar is studied. The yield of quinoline-soluble products increases considerably in the temperature range of coal softening. Optimal thermal-dissolution conditions are determined for selective production of quinoline-soluble pitch-like products. At 350–380°C, the yield of quinoline-soluble products is 70–73% after 1–2 h. The yields of the distillate fraction and the gas are 0.9% and 0.2%, respectively. The ash-free pitch-like product is a plastic mass with a softening temperature of 76–81°C. It consists mainly of polycyclic aromatic hydrocarbons with a few short alkyl substituents in the aromatic rings. The spatial structure mainly includes poorly structured polycyclic aromatic molecules of the γ component. The proportion of relatively ordered graphitelike packets is 31–37%. Each packet contains five stacked polycyclic aromatic molecules of diameter 17 Å. In terms of its composition and plasticity, the product is suitable as a source of alternatives to coal pitch