Differences in molecular composition of soluble organic species in two Chinese sub-bituminous coals with different reducibility

Naomaohu sub-bituminous (NS) with weak reducibility and Buliangou sub-bituminous (BS) with strong reducibility were extracted in isometric carbon disulfide/acetone mixed solvent to get extracts and extraction residues (ERs). The ERs were thermal dissolved in cyclohexane and methanol to get soluble portions (SPs). The yields of the extracts from NS (E_NS) and BS (E_BS) are 10.6% and 8.0%, respectively, and the total yields of the SPs from NS and BS at 300℃ are 36.3% and 11.5%, respectively, indicating the solubility of the organic species in NS are better than that in BS. Arenes are the dominated compounds both in E_NS and E_BS. The relative contents of aliphatic hydrocarbons and phenols in the SPs of NS are obvious higher than those of BS. The molecular weight distribution of the compounds in E_NS is wider than that in E_BS, while the molecular weight distribution of the compounds in the SPs from NS is narrower than that from BS.