Based on Product Selectivities

The argument can be extended to the more complex case of n-butane, for which there have been detailed studies of the effects of varying hydrogen pressure for platinum, palladium and rhodium on different supports (for ruthenium. 

The striking difference between platinum on the one hand and rhodium and iridium on the other lies in the former s ability to isomerise alkanes even on large particles, - whereas with the latter (and also with ruthenium ) it has only been observed at high temperatures with large particles that have been substantially deactivated. It might be thought that on these metals the high S2 values (Table 13.9) were a consequence of a frustration of the isomerisation route, because 

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