A highly active magnetic solid superbase catalyst for hydrocracking C-O bridged bonds of extraction residue from Huolinguole lignite

A highly active magnetic solid superbase (MSS) catalyst, Mg 2 Si supported on Fe 3 O 4 @SiO 2 , was synthesized and characterized using transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), vibrating sample magnetometry (VSM), X-ray diffraction (XRD), and CO 2 temperature-programmed desorption (CO 2 -TPD). The catalytic activity was assessed employing benzyl phenyl ether (BPE) as a coal-related model compound. The obtained Huolinguole lignite (HL) extraction residue underwent catalytic and non-catalytic hydrocracking over Mg 2 Si/Fe 3 O 4 @SiO 2 (MSS) catalyst in cyclohexane, methanol, ethanol and isopropanol in pressurized hydrogen (300 °C), in sequence. Soluble fractions 1–4 (SF1-SF4) were obtained from the reaction mixtures after they were removed from the autoclave and subjected to gas chromatography/mass spectrometer (GC/MS) analysis. The analysis results revealed that MSS catalyst can effectively enhance the contents of arenes, alkanes, alkenes and phenols and lower ethers and esters in the extraction residue, greatly increasing the heating value of the products. • A highly active and easily recoverable Mg₂Si/Fe₃O₄@SiO₂ magnetic solid superbase catalyst. • The C-O bond in extraction residue was cleaved specifically over the catalyst. • Much higher yield of soluble portion was obtained from catalytic hydrocracking.