Efficient Catalytic Hydrogenation of Lignin-Derived Phenolics Under Mild Conditions

This paper studies the catalytic hydrogenation reduction of lignin-derived phenolic compounds, such as catechol, guaiacol (O-methoxyphenol), phenol, P-methylphenol, O-ethylphenol, O-ethoxyphenol, etc. The reaction system focuses on the catalytic performance of hydrodeoxygenation reactions involving the phenolic derivatives of the lignin depolymerization products catechol and guaiacol. A series of Al2O3-TiO2 composite oxide supports with different Al/Ti ratios were prepared by a co-precipitation method, and a 5% Pd/Al2O3-TiO2 bifunctional catalyst was prepared by an impregnation method and characterized with XRD, SEM, BET, NH3-TPD, etc. Among these, the Pd/Al2Ti1 catalyst had the most excellent catalytic performance. At 100 °C and 2 MPa hydrogen pressure, the conversion of catechol was as high as 100%, and at 100 °C and 5 MPa hydrogen pressure, the conversion of guaiacol reached 90%.