The bituminous coal was extracted with different industrial solvents like coal tar (CT), heavy cycle oil (HCO) and with their blends to determine the influence of solvent type on the extract yield, composition, thermal behavior, properties such as solubility to toluene and quinoline. The extracts obtained at 380 °C represented pitch-like solid matter with the softening points of 72–127 °C depending on the solvent used. They were characterized using the elemental and group analysis, FTIR spectroscopy, TG-DTG thermogravimetry and liquid chromatography for benzo(a)pyrene concentration. Also, maltene fractions of some extracts were studied by GC–MS. The results showed coal dissolution and the properties of the extracts to differ greatly depending on the solvent used. Coal tar was more favorable solvent for coal dissolution than HCO. Good correlation between the extract aromaticity and the content of the toluene insolubles was observed. The maltene fractions of the extracts obtained with CT and CT blended with HCO consisted mainly of polycyclic aromatics, and that obtained with the HCO contained also large amount of aliphatic compounds. It was found that the amount of the carcinogenic benzo(a) pyrene (BaP) in the toluene soluble fractions of the extracts were different depending on the solvents used for extraction. The remarkable result was that the BaP concentrations in all extracts were much lower than in the solvents used.

    Abstract
    1 Introduction
    2 Experimental section
    3 Results and discussion
        3.1 Properties of the used coal and solvents
        3.2 The characterization of chemical and group composition of the extracts
        3.3 Characterization of the molecular structure of the extracts by FTIR spectra
        3.4 Thermal analysis, TG–DTA study of the extracts
        3.5 GC–MS analysis of the maltene fractions of extracts
    4 Conclusions
    Acknowledgements 
    References

• B. Avid(Institute of Chemistry and Chemical Technolog)
• M. Battsetseg(Institute of Chemistry and Chemical Technolog)
• B. Purevsuren(Institute of Chemistry and Chemical Technolog)
• G. Shiirav(Institute of Chemistry and Chemical Technolog)
• P. N. Kuznetsov(Institute of Chemistry and Chemical Technology SB RAS)
• L. I. Kuznetsova(Institute of Chemistry and Chemical Technology SB RAS)
• E. S. Kamenskii(Institute of Chemistry and Chemical Technology SB RAS)