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Nb2O5-supported bimetallic catalysts were prepared by the impregnation method applied for the in situ hydrogenation of guaiacol. Guaiacol can be effectively transformed into cyclohexanol over different bimetallic catalysts using alcohol as the hydrogen donor. Meanwhile, the effects of different hydrogen donors such as isopropanol, sec-pentanol, and ethylene glycol on in situ hydrogenation of guaiacol were investigated in detail, and the results showed that isopropanol is the best hydrogen supply solvent. Then, the dependence of Ni–Mn/Nb2O5 properties on metal loading, reaction time, reaction temperature, and reaction pressure was studied for the in situ hydrogenation of guaiacol by using isopropanol as the hydrogen donor. Guaiacol can be completely converted, and the yield of cyclohexanol reached 71.8% over Ni–Mn/Nb2O5 with isopropanol as the hydrogen donor at 200°C for 5 h. The structures and characteristics of better catalytic properties of the Ni–Mn/Nb2O5 catalyst were determined by BET, NH3-TPD, XRD, XPS, SEM, and TEM, and the results indicated the particle size of the metal was small (approximately 10 nm) and the metal particles are finely dispersed in the whole support. Therefore, a large number of medium acid sites were generated on the 10Ni-10Mn/Nb2O5 with a large specific surface area, which could increase the interface between the metal and the support and may be beneficial to the hydrodeoxygenation of guaiacol.

A simple oriented liquefaction with microwave assistance was introduced to produce phenolic compounds and cellulose nanofibers from the comprehensive utilization of biomass. Effects of process parameters on the yield and composition of liquefied straw products were investigated. Liquefied products was separated into liquid and solid products. The highest phenolics content (72.87%) in liquid products was achieved; the yield of nanofibers from liquefied solid products was 47.43 wt %. With stepwise extraction, phenolics with nice reactivity were largely separated into three fractions. They were mainly composed of phenolic compounds and aromatic derivatives and had good solubility in organic solvents. After a chemical-purified treatment, solid products containing highly crystalline cellulose were converted into nanofibers with good application. These simple processes achieve a comprehensive use of liquefied products to various synthetical directions based on different molecular structures and chemical solubility. Directional liquefaction was significantly effective to produce renewable phenolics and nanofibers and realizes the integrated valorization of whole components in waste biomass.