Synthesis and study of mono-schiff base MnIII complexes with aza-crown or morpholino pendant as catalyst in aerobic oxidation of p-xylene to p-toluic acid

Novel mono-Schiff base Mn-III complexes with pendant aza-crown or morpholino groups have been synthesized and studied as catalysts in aerobic oxidation of p-xylene to p-toluic acid. The oxidation of p-xylene to p-toluic acid with air at 120 degrees C under normal atmospheric pressure occured efficiently in the presence of aza-crown ether substituted mono-Schiff base Mn-III complexes. Significant selectivity ( up to similar to 90%) and conversion levels ( up to similar to 38%) were obtained. The effect of the aza-crown ether pendant in Mn-III Schiff base complexes on the oxidation of p-xylene was also investigated by comparison with the morpholino pendant analogues. The addition of alkali metal ions accelerated the rate of conversion of p-xylene to p-toluic acid.