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Some mono- and bimetallic-supported Ru/ZSM-5, Ru–Re/ZSM-5, Ru–Rh/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, n -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/TiO 2 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. |
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