Synthesis of novel of Mn(II), Co(II), and Cu(II) Schiff base complexes and their high catalytic effect on bleaching performance with H2O2

Oxidation catalysts are used in a wide range of industrial processes. For instance, stain bleaching in detergents, bleaching of raw cotton and wood pulp, and drying of alkyd-based paint can be given as examples of oxidation catalysts. In this study, methyl 2-(((3-hydroxynaphthalene -2-yl) methylene) amino) benzoate synthesized as the structure of a new Schiff base ligand by carrying out over 2-hydroxy-1-naphthaldehyde and methyl 2-aminobenzoate. By the reactions of the synthesized Schiff base ligand and Cu(II), Mn(II), and Co(II) acetate salts, their ML2 type complexes were obtained. The structural characterizations of obtained metal ion-Schiff base complexes were performed using FT-IR, 1H-NMR, 13C-NMR, UV-Vis, MALDI-TOF, elemental analysis and melting point methods. The bleaching performances of the prepared Schiff base complexes were examined by the degradation of morin as a hydrophilic dye that characterizes the wine stains. The bleaching processes of Schiff base complexes in the presence of catalyst and H2O2 in an aqueous solution buffered with Na2CO3/ NaHCO3 at pH: 10.5 were investigated using the online spectrophotometric method. It was found that the prepared catalysts exhibited better bleaching performance at 25 °C than that of tetraacetylethylenediamine (TAED) as a bleach activator commercially used in powder detergent formulations.