Catalytic hydroxylation of phenol using immobilized late transition metal salicylaldimine complexes

Immobilized late transition metal complexes based on salicylaldimine ligands were used as catalysts in the wet air hydroxylation of phenol in the presence of hydrogen peroxide. Three metals, viz. cobalt, nickel and copper, and two different kinds of supports, namely, amorphous silica and mesoporous MCM-41, were employed. The effect of pH on the hydroxylation process was also investigated. It was observed that the regioselectivity of the hydroxylation process strongly depends on the kind of support employed.

Graphical abstractLate transition metal complexes of salicylaldimine ligands immobilized on amorphous silica and MCM-41 were used as catalysts in the hydroxylation of phenol in the presence of hydrogen peroxide. Product selectivity was shown to be highly dependent on the type of support employed. Figure optionsDownload full-size imageDownload as PowerPoint slide