Effect of Chlorine on the Properties of Ru/Al₂O₃

Abstract

Ru/Al 2 O 3 catalysts with different chlorine contents were prepared using RuCl 3 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/Al 2 O 3 . 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.

Effect of Organic Additives on the Performance of Nano‐sized Ru‐Zn Catalyst

“…(2) Considering the Pauling electronegativities of Ru (2.2), N (3.0) and O (3.4), metallic Ru may donate an electron to O in the ether linkages (or N in the amine groups) and a lot of Ru δ＋ species may be formed. Mazzieri et al 30 found that the cyclohexene selectivity increased with the decrease of the Ru 0 /Ru δ＋ ratio. They suggested that cyclohexene might be more weakly adsorbed on the most electron-deficient Ru species and easily desorbed by avoiding its further hydrogenation to cyclohexane and the cyclohexene selectivity increased.…”

Selective Hydrogenation of Benzene to Cyclohexene Over Colloidal Ruthenium Catalyst Stabilized by Silica

“…Thus, the preparation of cyclohexene has attracted great research interest academically and industrially. Among various synthetic routes, such as cyclohexanol dehydration, cyclohexane halide dehydrohalogenation, cyclohexane dehydrogenation and so on [1][2][3], selective hydrogenation of benzene to cyclohexene (SHBC) receives much attentions due to economical requirements and environmental considerations [4][5][6].…”

Effects of Manganese Salts on Ru/Mn/Al₂O₃ Catalytic Activity and Stability for Fischer-Tropsch Synthesis

“…4(d)-(f) showed one hydrogen reduction peak centered near 520 K assigned to the reduction of RuO2 to Ru 0 . No ruthenium chloride or ruthenium oxychloride were observed over the catalysts 43), 44) . However, ruthenium oxychloride was clearly observed on Ru/ Mn(Cl)/Al2O3 in Fig.…”