Polymetallic cluster compositions useful as hydrocarbon conversion catalysts
AssigneeExxon Research & Engineering Co.
InventorJohn H. Sinfelt
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Abstract
Compositions comprising iridium and at least one additional metal, preferably platinum, are disclosed in which the iridium and the additional metal or metals are present on a refractory support as highly dispersed polymetallic clusters. The metallic atoms in a cluster are separated by distances of about 2.5 to 4.0A. The degree of coverage of the surface of said refractory support by said polymetallic clusters is lower than about 10% and frequently lower than about 1%. The compositions are useful as hydrocarbon conversion catalysts, and iridiumplatinum catalysts containing a halogen moiety are especially useful for promoting naphtha reforming reactions.
Claims19
A catalyst composition comprising:
- polymetallic clusters of iridium and at least one additional metal selected from the group consisting of ruthenium, rhodium, palladium, osmium, platinum, copper, silver, gold and mixtures thereof, dispersed on a refractory support,
- the iridium being present in the overall catalyst composition in an amount greater than 0.1 wt. %, each additional metal being present in an amount of 0.1 to 1.0 wt. %,
- the metal dispersion, defined as the percentage of metal atoms in the clusters which are present on the surface, being greater than about 20%,
- the average atomic ratio of iridium to each additional metal in the overall catalyst varying from about 1 :
- 10 to 10 :
- 1,
- the metallic atoms within a cluster being separated by distances of about 2.5 to 4.0A, and
- the degree of coverage of the surface of the refractory support by the polymetallic clusters being less than about 10%.
A catalyst composition comprising:
- polymetallic clusters of iridium and platinum dispersed on an inorganic oxide support,
- the iridium being present in the overall catalyst composition in an amount greater than 0.1 wt. %, the platinum being present in an amount of about 0.1 to 1 wt. %,
- the metal dispersion, defined as the percentage of metal atoms in the clusters which are present on the surface, being greater than about 75%,
- the average atomic ratio of iridium to platinum in the overall catalyst varying from about 1:10 to 10:1,
- the metallic atoms within a cluster being separated by distances of about 2.5 to 4.0 A, and
- the degree of coverage of the surface of the refractory support by the polymetallic clusters being less than about 10%.
Dependencies are inferred from the claim text.