A study of Fe(III)TPPCl encapsulated in zeolite NaY and Fe(III)NaY in the oxidation of n-octane, cyclohexane, 1-octene and 4-octene

Abstract

The Fe(III)TPPCl (Fe(III)tetraphenylporphyrin chloride) complex was immobilized using the encapsulation method in order to entrap the complex inside the faujasite NaY zeolite to obtain FeTPP–NaY. This was achieved by adding the FeTPP as a template during the synthesis of NaY. The ICP results show that a 0.3 wt% loading of Fe was achieved and the XRD confirmed the faujasite Y structure. Further to this, a Fe–NaY zeolite was synthesized for the purpose of comparing it with FeTPP–NaY. The synthesized FeTPP–NaY and Fe–NaY were tested in the oxidation of n-octane, 1-octene, 4-octene and cyclohexane to oxygenates in the liquid phase using acetonitrile as a solvent, H2O2 and tert-butyl hydroperoxide in water as oxidants at 80 °C. Conversions of n-octane of 1.8 and 2.9 % and selectivities to terminal products of 13 and 8.8 % were achieved using FeTPP–NaY and Fe–NaY, respectively. Conversions of 1.4 and 1.8 % were achieved for 1-octene and 4-octene, respectively. A higher conversion of 18 % for cyclohexane was observed. These results show that cyclohexane is most reactive under these conditions and that the NaY matrix is not suitable for selective linear paraffin oxidation. Furthermore, leaching of Fe from the Fe–NaY was observed, even though the faujasite NaY structure was maintained as confirmed by XRD, while for FeTPP–NaY, the leaching of Fe was not observed.