Production of cyclohexane from lignin degradation compounds over Ni/ZrO2–SiO2 catalysts

• ZrO2–SiO2 mixed oxides as catalyst supports.
• ZrO2–SiO2 mixed oxides possess amphoteric character and excellent textural properties.
• Phenol and guaiacol were completely converted over Ni/ZrO2–SiO2 catalyst.
• The selectivity for the desired product cyclohexane was in excess of 90%.

The main products of lignin degradation are phenolic compounds. It is meaningful to study the processes by which cyclohexane is produced from phenolic compounds via hydrodeoxygenation (HDO), because it could be used as fuel additives, chemical feedstock and solvent. In this work, support material ZrO2–SiO2 mixed oxides with different Si/Zr ratio were synthesized, and a series of Ni/SiO2–ZrO2 catalysts with different Ni loading were prepared by impregnation method. The exploration of HDO process was carried out using phenol and guaiacol as model compounds. Effects of Si/Zr ratio, Ni loading and reaction temperature on conversion of phenol and guaiacol as well as distribution of HDO products were systematically investigated. The results showed that almost all of phenol and guaiacol could be effectively converted into O-free products. And the selectivity of cyclohexane was in excess of 90%.