Metathesis of Propene on Molybdenum−Alumina-Pillared Montmorillonite

The preparation, characterization, and catalytic activity of molybdenum−alumina-pillared clays for the metathesis of propene were studied. Two solutions containing molybdenum and aluminum were used in the preparation of the intercalation solutions. In the first, a mixed hydroxy−aluminum−molybdenum solution (MoAl) was prepared by slow addition of NaOH to a solution of mixtures (AlCl 3 and MoCl 5 ). The second solution (Mo + Al) was obtained by dissolving MoCl 5 in an aged solution of aluminum polycation. These solutions were used to prepare two molybdenum−alumina-pillared clays. Finally, an alumina-pillared clay (AlPILC) was used as support and impregnated with a molybdenum solution. Nitrogen adsorption data obtained from very low relative pressures were used for the characterization of the microporosity of the solids. The Dubinin−Radushkevich formalism was used to describe the volume filling of micropores and confirmed the existence of a bimodal distribution of the micropore sizes in the pillared clays. The micropore distributions obtained by the Horvath−Kawazoe approach for the two molybdenum−alumina-pillared clays showed a modification of their microporous surface with respect to the AlPILC. The acidity and catalytic activity in the propene metathesis reaction of the molybdenum−alumina-pillared clays and a comparison with two reference catalysts (Mo/SiO 2 and Mo/Al 2 O 3 ) are also reported.