Cluster Model DFT Study of the Intermediates of Benzene to Phenol Oxidation by N2O on FeZSM-5 Zeolites

An Fe(II) ion at an a-cation exchange position of ZSM-5 zeolite (Fe/Z) was taken as a model for the active site in the nitrous oxide decompn. and in the selective oxidn. of benzene to phenol with nitrous oxide. The oxygen deposited by decompn. of N2O is commonly referred to as a-oxygen (OFe/Z). Cluster model DFT calcns. show that the interaction of the OFe/Z center with benzene resulted easily in arene oxide formation. The results indicate a rather low activation energy for this step. Possible transformations of the adsorbed arene oxide are considered and the exptl. evidence for the absence of the kinetic H/D isotope effect in phenol formation is discussed. It is concluded that the rate-limiting step for the in situ oxidn. of benzene to phenol is the desorption of the product. [on SciFinder (R)