Selective cyclohexanol production from the renewable lignin derived phenolic chemicals catalyzed by Ni/MgO

Selective production of cyclohexanol from renewable lignin derived phenolic has been presented using the cost-efficient catalyst Ni/MgO which shows excellent catalytic activity in the hydrogenation reaction and dehydroxylation inhibition. Guaiacol, one of the most abundant lignin depolymerization products, was selected as the model compound. The hydrogenation performance of guaiacol was investigated over various catalysts. The effect of the reaction parameters was also studied. The results showed that guaiacol could be efficiently converted to cyclohexanol, which is a highly value-added precursor and additive for bio-fuel that is generally obtained from unsustainable fossil resources. Under the mild condition (160 °C, 3 h and 3 MPa H2), more than 97.74% of guaiacol conversion with 100% cyclohexanol selectivity can be achieved in the presence of 20% Ni/MgO. Intensive catalyst characterization demonstrated that the efficient promotion effect of the base carrier for the Ni active center was responsible for efficient guaiacol conversion and selective cyclohexanol production. Furthermore, the Ni/MgO catalyst showed excellent recyclability, where no significant activity loss was observed even after four runs. Moreover, the reaction pathway and the catalytic mechanism are proposed.