Selective Hydrodeoxygenation of Guaiacol to Cyclohexanol Catalyzed by Nanoporous Nickel

Abstract

Cyclohexanol is an important feedstock in the chemical industry and the selective hydrodeoxygenation of lignin-derived guaiacol to cyclohexanol have gained increasing research attention in recent years. In this work, a series of nanoporous metal catalysts were employed for the hydrodeoxygenation of guaiacol and nanoporous Ni (NP-Ni) exhibited high catalytic performance for the preparation of cyclohexanol. With water as solvent, 100% conversion of guaiacol and over 90% selectivity to cyclohexanol were achieved at 180 °C and 2 MPa for 4 h. In order to further promote the stability of NP-Ni, induction melting, vacuum arc melting and mechanical alloying were separately employed for the preparation of NiAl precursor alloy. Mechanical alloying seemed to be an effective method for the alloying process and the as-prepared NP-Ni could keep almost stable after 10 times recycling. Furthermore, the reaction mechanism was investigated with NP-Ni for guaiacol hydrodeoxygenation. Scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron micrographs (TEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) were employed for the characterization of NiAl alloy and the optimal preparation methods of NP-Ni were acquired according to the characterization results.