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7017725 
Journal Article 
Alkaline wet oxidation of lignin over Cu-Mn mixed oxide catalysts for production of vanillin 
Jeon, W; Choi, I; Park, JiY; Lee, J; Hwang, K; , 
2020 
Yes 
Catalysis Today
ISSN: 0920-5861 
ELSEVIER 
AMSTERDAM 
352 
95-103 
WOS:000535914800014 
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 degrees 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, N-2-physisorption, SEM-EDS, and H-2-TPR. The XRD and N-2-physisorption analyses showed a non-stoichiometric spinel structure (Cu1.5Mn1.5O4) 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. 
Lignin depolymerization; Alkaline wet oxidation; Cu-Mn mixed oxide; Spinel structure; Vanillin