Hydroconversion of hydrocarbons over Ru-containing supported catalysts prepared by metal vapor method

Some mono- and bimetallic-supported Ru/ZSM-5, Ru-Re/ZSM-5, Ru-Kh/ZSM-5. Ni-Ru/ZSM-5 and Ru-Ni/ZSM-5 catalysts were prepared by metal vapor method. The carbon-carbon cleavage activity and the selectivity of prepared catalysts were investigated in hydroconversion of alkanes (n-pentane, a-hexane, n-heptane, 2-methylpentane) and cycloalkanes (cyclopentane, cyclohexane, methylcyclopentane). These catalysts demonstrate extremely high C-C bond splitting activity in tested hydrocarbons. The magnitude of the effect for methylcyclopentane reaches a factor of about 70 at 393 K in comparison with the activity of known Ru/TiO2 at 433 K. The increase in activity for the metal vapor method prepared Ru-containing catalysts is due mainly to the presence of highly dispersed ruthenium particles on a zeolite support. The selectivity of Ru/ZSM-5 remains in a range expected for known well-dispersed Ru-containing catalysts, whereas these values can be modified to a large extent by addition of a second metal to the mono-metallic samples: Ru-Re/ZSM-5 shows high selectivity in the isomerization of n-hexane to 2- and 3-methylpentanes, while Ni-Ru/ZSM-5 ruptures mostly the central carbon-carbon bond in the n-heptane molecule. The rates of hydroconversion of tested hydrocarbons, based on a lodged ruthenium, on most of the bimetallic samples are much higher than over Ru/ZSM-5. (C) 2000 Elsevier Science B.V. All rights reserved.