Synthesis and Catalytic Activity of Vanadia-Doped Iron-Pillared Clays for Cyclohexene Epoxidation

We prepared the catalysts based on montmorillonite which was obtained from purified Algerian clay (Maghnia, Tlemcen). The montmorillonite was pillared by iron and doped with vanadia at different ratios V/FeMont. The materials prepared were characterized by UV-visible and nitrogen adsorption-desorption at 77 K. The surface acidities of the samples and their structures were also investigated with the gas phase adsorption data of pyridine, using the FT-IR spectroscopic technique. The FT-IR spectra of the samples reflected mainly the structure of Bentonite. The nitrogen adsorption-desorption isotherms of the samples were type IV shaped and showed in general mesoporous structures with pore openings of 4 nm. An infrared study of pyridine adsorption on the samples showed both Lewis and Bronsted sites on their surfaces. Vanadia-doped ironpillared clay was tested in cyclohexene epoxidation. These materials are good catalysts for liquid phase epoxidation of cyclohexene, when using TBHP as oxidant. The effects of various factors on catalyst reactivity were also studied. The performance and selectivity of the catalysts were enhanced in aprotic/apolar solvents (heptane) when compared to protic/apolar (acetic acid) or aprotic/polar (acetonitrile) solvents. Catalytic activity values of the materials were also calculated.