A novel Ru-B/SiO2 amorphous catalyst used in benzene-selective hydrogenation

A supported Ru-B/SiO2 amorphous catalyst was prepared by impregnation and chemical reduction by KBH4 solution. Its amorphous character was determined by XRD and DSC. During the liquid phase benzene-selective hydrogenation to cyclohexene in the presence of ZnSO4, the benzene conversion over the as-prepared Ru-B/SiO2 amorphous catalyst was 3.2%/h g Ru and the selectivity was 49.7%, which were much better than the activity (2.3%/h g Ru) and selectivity (22.2%) over the Ru/SiO2 catalyst obtained by H-2 reduction. According to various characterizations, including XPS, XRD, ICP, SEM and hydrogen chemisorption, the better selectivity of Ru-B/SiO2 amorphous catalyst is discussed. The promoting effect of boron on the water adsorption by the catalyst is important, since the existence of a layer of water on the surface of the Ru-based catalyst is favorable for the hydrogenation selectivity toward cyclohexene. (C) 1999 Elsevier Science B.V. All rights reserved.