Selective Production of Arenes from Lignite-Derived Phenols via Catalytic Hydrodeoxygenation over an Unsupported CoMoS Catalyst

Lignite shows good potential as a feedstock for arene production due to its structural characteristics. In this study, an unsupported CoMoS catalyst for catalytic hydrodeoxygenation (HDO) of lignite-derived phenols was prepared by using ball-milling and hydrothermal methods. The CoMoS catalyst contained MoS₂ and Co₉S₈ as the active components for HDO, with interactions among Co, Mo, and S. The incorporation of sulfur atoms in the catalyst generated a large number of strong acid sites. The CoMoS catalyst exhibited good activity for converting various phenolic monomers into the corresponding arenes, achieving satisfactory arene selectivity and maintaining good recyclability at 300 °C and 2 MPa H₂. High yields of phenols were produced from Shengli lignite by alkali-catalyzed supercritical methanolysis, which were further converted into arenes with a relative content of 71.9% via HDO over the CoMoS catalyst. This two-step strategy efficiently converted the aromatic units in lignite into arenes under mild conditions.