Environmentally friendly and efficient catalysis of cyclohexane oxidation by iron meso-tetrakis(pentafluorophenyl)porphyrin immobilized on zinc oxide

•ZnO coordinates to Fe (TPFPP) more strongly than BM.•Fe (TPFPP)/ZnO provides greater yields of KA oil.•ZnO enhances promotion with Fe (TPFPP) catalysis.

The use of zinc oxide-promoted catalysis of tetrakis(pentafluorophenyl)porphyrin iron chloride for cyclohexane oxidation was studied. Tetrakis(pentafluorophenyl)porphyrin iron chloride was immobilized onto zinc oxide, generating zinc oxide-supported tetrakis(pentafluorophenyl)porphyrin iron chloride, which was characterized by a variety of spectroscopic techniques and was employed to provide a stable catalyst for the oxidation of cyclohexane in the absence of any solvents or co-reductants. The small amount of tetrakis(pentafluorophenyl)porphyrin iron (1.0 μmol) in the supported catalyst could be reused 10 times for the oxidation optimized at 150 °C and 0.7 MPa. This stable catalyst provided higher turnover numbers and yields of ketone and alcohol than those obtained using the boehmite-supported tetrakis(pentafluorophenyl)porphyrin iron chloride. These results were attributed to the following factors: (1) stronger coordination of ZnO to the iron porphyrin improved its catalysis of the oxidation. (2) Improved dispersal of the iron porphyrin by ZnO enhanced the effective catalytic center. (3) Faster decomposition of peroxide into the main products.

Graphical abstractAn environmentally friendly and efficient catalyst, iron meso-tetrakis(pentafluorophenyl)porphyrin promoted by ZnO, catalyzes the oxidation of cyclohexane with O2 and provides an excellent yields of KA oil.Figure optionsDownload full-size imageDownload as PowerPoint slide