Alkaline wet oxidation of lignin was performed to study the effect of Cu-Mn mixed oxide catalysts on the production of vanillin at between 120–180 °C using H₂O₂ as an oxidizing agent. The mixed oxide catalysts were prepared by a sol-gel method with mixing ratios of Cu to Mn between 0.25 and 0.75 and characterized by XRD, XPS, N₂-physisorption, SEM-EDS, and H₂-TPR. The XRD and N₂-physisorption analyses showed a non-stoichiometric spinel structure (Cu_1.5Mn_1.5O₄) and a relatively high BET surface area of the mixed oxides compared with pure Cu and Mn oxides, respectively. In addition, the Cu-Mn mixed oxide catalysts exhibited better redox properties and a higher catalytic performance for lignin oxidation to vanillin and other aromatic oxygenates. Higher Cu contents in the mixed oxide catalysts promoted the over-oxidation of vanillin producing vanillic acid along with the formation of more surface oxygen species on the catalyst surface. Finally, a possible reaction pathway for the catalytic conversion of lignin to vanillin was proposed.

使用H ₂ O ₂作为氧化剂，对木质素进行碱性湿法氧化，以研究Cu-Mn混合氧化物催化剂在120-180°C之间对香兰素生产的影响。通过溶胶-凝胶法制备混合氧化物催化剂，其中Cu与Mn的混合比为0.25至0.75，并通过XRD，XPS，N _2-物理吸附，SEM-EDS和H ₂ -TPR表征。XRD和N _2-物理吸附分析显示出非化学计量的尖晶石结构（Cu _1.5 Mn _1.5 O ₄）和混合氧化物分别比纯Cu和Mn氧化物高的BET表面积。另外，Cu-Mn混合氧化物催化剂表现出更好的氧化还原性质和对木质素氧化为香兰素和其他芳族含氧化合物的更高的催化性能。混合氧化物催化剂中较高的Cu含量促进了香草醛生成香草酸的过度氧化，同时在催化剂表面形成了更多的表面氧。最后，提出了木质素催化转化为香兰素的可能反应途径。