Mixed metal cobalt titanium oxide (CoTiO3) prepared by solution phase method has been evaluated for the liquid phase catalytic oxidation of vanillyl alcohol to vanillin using H2O2 as an oxygen source.

Lignin is the second most abundant naturally occurring macromolecule found in plant cell-wall, vascular components and woody stems. It is the largest renewable source of aromatic biopolymer. However, lignin is recalcitrant to be broken down by most chemicals. This is because of its complicated heterogeneous molecular structure. However, lignin depolymerization has huge potentials for the synthesis of a number of useful chemicals, perfumes and pharmaceuticals and toiletries. The oxidation products of lignin are important precursors for pulp/paper and food industries, synthetic thin films. Vanillin, veratryl aldehyde and para-benzoquinone are the oxidation products of lignin. These chemicals are the precursors of optically active alcohol, ketone, violuric acid and benzaldehyde. However, the oxidation of biolignin has been remaining a challenging task. Green catalytic approaches might be an interesting solution for the selective depolymerization of lignin into various platform chemicals. Metal oxide/silica supported nanoporous gold has received strong attention as green catalyst for the transformation of various natural polymers. Mesoporous metal oxide/silica provide enlarged surfaces for the breakdown of C-C, C-H and C-OH bonds. This paper has reviewed various green catalytic approaches for the control depolymerization of biolignin into platform chemicals.