Catalytic hydroconversion of Yinggemajianfeng lignite over difunctional Ni-Mg2Si/γ-Al2O3

•Ni-Mg2Si/γ-Al2O3 is effective for the CHC of the extract and ER from YL.•The CHC includes the hydrocracking of covalent bonds & hydrogenation of ARs in YL.•Total yield of cyclanes from the CHC is much higher than from the NCHC. A highly active difunctional Ni-Mg2Si/γ-Al2O3 was prepared by thermally decomposing nickel tetracarbonyl onto γ-Al2O3 impregnated with Mg2Si. The non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) of the extract (E) and extraction residue (ER) from Yinggemajianfeng lignite were investigated over Ni-Mg2Si/γ-Al2O3 at 240 °C in n-hexane. Benzyloxybenzene and oxybis(methylene)dibenzene were used as lignite-related model compounds to speculate the possible mechanisms for the catalytic hydrocracking and hydrogenation over Ni-Mg2Si/γ-Al2O3. As a result, more organic matter in ER was converted to soluble portion (SP) by the CHC than by the NCHC. The main SP from the CHC are chain alkanes and cyclanes, while that from the NCHC is rich in arenes and oxygen-containing organic compounds. The results indicate that Ni-Mg2Si/γ-Al2O3 effectively catalyze the hydrocracking of >Calk–O– linkages and the hydrogenation of aromatic rings in E and ER.