Effect of Chlorine on the properties of Ru/Al2O3

VANINA MAZZIERI, FERNANDO COLOMA PASCUAL, PABLO L'ARGENTIERE, NORA FÍGOLI

INDUSTRIAL & ENGINEERING CHEMICAL RESEARCH

American Chemical Society

Lugar: The University of Texas at Austin. Dep. of Chemical Engineering 1 University Station CD 400 Austin TX 78712-1052; Año: 2003 vol. 42 p. 2269 - 2272

0888-5885

Ru/Al2O3 catalysts with different chlorine contents were prepared using RuCl3 as the precursor. Different HCl concentrations in the impregnation solution or different treatments after impregnation were used. The catalysts were characterized by temperature-programmed reduction, X-ray photoelectron spectroscopy, and hydrogen chemisorption. They were tested in the selective hydrogenation of benzene to cyclohexene in a stirred tank reactor at 373 K and 3 MPa hydrogen pressure. It was found that different electronic states of Ru appear according to the chlorine content on Ru/Al2O3. The electronic state of Ru influences the selectivity to cyclohexene. The results seem to support that the most electron-deficient Ru species may adsorb cyclohexene more weakly. When cyclohexene is more weakly adsorbed, it could be more easily desorbed by avoiding its further hydrogenation to cyclohexane, thus increasing selectivity.2O3 catalysts with different chlorine contents were prepared using RuCl3 as the precursor. Different HCl concentrations in the impregnation solution or different treatments after impregnation were used. The catalysts were characterized by temperature-programmed reduction, X-ray photoelectron spectroscopy, and hydrogen chemisorption. They were tested in the selective hydrogenation of benzene to cyclohexene in a stirred tank reactor at 373 K and 3 MPa hydrogen pressure. It was found that different electronic states of Ru appear according to the chlorine content on Ru/Al2O3. The electronic state of Ru influences the selectivity to cyclohexene. The results seem to support that the most electron-deficient Ru species may adsorb cyclohexene more weakly. When cyclohexene is more weakly adsorbed, it could be more easily desorbed by avoiding its further hydrogenation to cyclohexane, thus increasing selectivity.2O3. The electronic state of Ru influences the selectivity to cyclohexene. The results seem to support that the most electron-deficient Ru species may adsorb cyclohexene more weakly. When cyclohexene is more weakly adsorbed, it could be more easily desorbed by avoiding its further hydrogenation to cyclohexane, thus increasing selectivity.