Catalytic activity and selectivity of prepared catalysts (Fe2O3/ (

Iron oxide nanoparticles supported on zirconia were prepared by precipitation-deposition method and characterized by XRD, SEM, FT-IR, TGA/DTA, surface area and particle size analysis. Catalytic activities of the catalysts were tested in the gas-phase conversion of cyclohexanol in a fixed-bed flow type, Pyrex glass reactor, at 433 -463 K. Major detected products were cyclohexanone, cyclohexene and benzene, depending on the used catalyst. The rate of reaction was significantly raised by the introduction of molecular oxygen in the feed gas, thereby suggesting the oxidation of cyclohexanol to cyclohexanone. Furthermore, the catalytic activity of iron oxide nanoparticles supported on zirconia treated with hydrogen at 553 K for 2 hours, was more selective and better than the unreduced iron oxide nanoparticles supported on zirconia, in the gas-phase oxidation of cyclohexanol to cyclohexanone. Experimental results showed that there was no leaching of metal, and that the catalyst was thus truly heterogeneous.

Direct aldol reactions have been successfully performed using aromatic aldehyde and cyclic ketone in nonpolar solvent by using immobilized picolylamine on zirconia as a catalyst, in a double walled batch reactor. The prepared catalyst was characterized by SEM, XRD and FT-IR. FT-IR peaks reveal the presence of picolylamine on the surface of zirconia. The catalyst shows excellent catalytic activity in aldol reaction of cyclohexanone with benzaldehyde in cyclohexane giving 2-hydroxyphenylmethylcyclohexanone (55.7% yield) in 4 hr at 80˚C. Furthermore, the catalyst is recoverable by simple filtration and could be used several times without significant loss in activity.