| Abstract |
First-row-transition-metal silica coated magnetite nanoparticles (MNPs), Fe3O4@SiO2-M2+ [M = Mn2+ (1), Co2+ (2), Cu2+ (3) or Zn2+ (4)], were evaluated as catalysts for the selective oxidation of cyclohexane to cyclohexanone and cyclohexanol. The catalytic reaction occurred under mild conditions, using microwave-assisted heating in added solvent-free medium producing water as the only by-product. The manganese (1) and copper (3) surface enriched silica-coated MNPs leaded to the highest yield of oxygenated products (24\% and 21\%, respectively) after 2 h at 80 degrees C using hydrogen peroxide as oxidant. These surface modified MNPs can be readily isolated by using an external magnet and no significant loss of activity is observed when reused up to 5 consecutive runs. |
