Investigation on the macromolecular network structure of Xianfeng lignite by a new two-step depolymerization

► Most of organic matter in XF became soluble fraction by TE and oxidation. ► Main linkages between aromatic rings in XF structure are -CH2- and -CH2CH2-.► Benzene ring should be an important aromatic ring in the macromolecular structure. ► Some aliphatic and carbonyl group-containing species are trapped in the structure. ► The species trapped in the structure can be thermally extracted with 1-MN.