Catalytic Potential of Mononuclear Cr(III)-Imine Complexes for Selective Oxidation of Benzyl Alcohol by Aqueous H2O2

Chromium(III) complexes were derived, as tri- and tetradentate imine chelates, from 2-hydroxy-1-napthaldehyde or 3-ethoxysalicylaldehyde with 2-aminophenol or 1,2-phenylenediamine. The catalytic potentials of Cr(III)-imine chelates were probed and tested in the chemoselective benzyl alcohol oxidation to benzaldehyde (BA) within an eco-friendly terminal oxidant (i.e., H2O2). The effect of various applicable parameters in the catalytic systems (e.g., solvents, temperature, and catalyst molar ratios) was studied. From the obtained results, it is found that the most favored and suitable solvent applied is acetonitrile at best reaction conditions; temperature 80 °C after 4 h. The mechanistic aspects of the Cr(III)-catalyzed oxidation were tentatively described and discussed based on electron and oxygen transfer processes.