Catalytic hydroconversion of guaiacol and a poplar lignin derivate to cyclanes over Ni_20%/₂₅

Upgrading lignin derivatives (LDs) to cyclanes by catalytic hydroconversion facilitates the value-added utilizations. Ni-20%/beta(25) was prepared via a deposition-precipitation method and used for catalytically hydroconverting guaiacol and a poplar lignin derivate (PLD). Guaiacol was completely converted to cyclohexane (CH) as the main product in the yield of 93.3 mol% at 220 degrees C under initial hydrogen pressure of 4 MPa for 2 h, while the PLD was significantly converted to cyclanes over Ni-20%/beta(25) for 8 h. Density functional theory combined with experiments explained the related mechanisms, i.e., H-2 was activated to H center dot center dot center dot H, which was split to relatively mobile H+ and immobile H- over Ni-20%/beta(25). H.H transfer to benzene ring (BR) leads to BR hydrogenation and subsequent H+ transfer to the oxygen atom in -OCH3 and -OH connected to the hydrogenated BR induces the demethoxylation and dehydroxylation.