The role of nanoporous carbon materials in catalytic cyclohexane oxidation

The C-scorpionate iron(II) complex [FeCl2(Tpm)] [Tpm = kappa(3)-HC(C3H3N2)(3)] was immobilized on three nanoporous carbon supports to produce active, selective and recyclable catalysts for the oxidation of cyclohexane. The influence of the porous carbon supports on the performance of the heterogenized [FeCl2(Tpm)] catalyst was investigated using materials with distinct porosity: microporous (GL50-ox, wet oxidized GL50 Norit sample, and S, sisal-derived activated carbon prepared by chemical activation), and mesoporous (CMK-3) materials. The heterogenized systems exhibited good activity and rather high selectivity to the formation of KA (ketone-alcohol) oil (cyclohexanol and cyclohexanone mixture) from microwave-assisted oxidation of cyclohexane, and allowed their easy recovery and reuse, at least for four consecutive cycles. The most important outcome of this work was the significant self-catalytic activity observed for the pristine carbon materials GL50-ox and CMK-3 towards cyclohexane oxidation under Microwave irradiation, in the absence of the iron complex.