Obtaining Polyaromatic Raw Materials for Needle Coke By Solvolysis Of Russian And Mongolian Coals using Coal- And Petroleum-derived Heavy Residues as Solvents

The purpose of this research is to obtain polyaromatic substances via solvolysis of Mongolian and Russian coals and their characterization as raw materials for needle coke preparation.

The quinoline-soluble products were obtained via coal solvolysis at a moderate temperature of 380°C using heavy hydrocarbon fractions of coal and petroleum origin as solvents.

The chemical and group composition and molecular structure of the soluble products were characterized by FTIR, GC-MS, gas and liquid phase chromatography, and TG-DTG-DSC techniques.

The products obtained from the coal solvolysis were pitch-like matter soluble in quinoline up to 90-95%. The main components were represented predominantly by polycondensed aromatics, and their structures depended on the coal and solvent used. A remarkable feature of the polyaromatic products was a reduced concentration of carcinogenic benzo(a)pyrene (up to 40 times compared to commercial coal-tar pitch).

The product obtained with coal tar as solvent was highly aromatic, and its aromatic nuclei consisted predominantly of polycondensed sparsely substituted cycles. The product obtained with petroleum-derived solvent was less aromatic, and the aromatic units were highly alkylated with fairly long alkyl chains. The pitch-like product with the intermediate structural parameters was obtained using a binary solvent.

In terms of composition and molecular structure, the pitch-like products obtained via coal solvolysis can serve as a new polyaromatic feedstock with reduced carcinogenicity for the preparation of valuable carbon materials. By selecting solvents and coals, it is possible to optimize the molecular-structural characteristics of the products in order to obtain feedstock for the production of high-tech carbon materials, including needle coke and valuable chemicals.