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AssigneeExxon Research & Engineering Co.
InventorsGary B. McVicker, M. Albert Vannice
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This invention relates to unique supported potassium (or rubidium) - Group VIII-metal cluster catalysts which are useful in CO/H.sub.2 reactions (Fischer-Tropsch synthesis reactions). The novel catalysts of the instant invention are prepared by depositing well characterized potassium (or rubidium) - Group VIII-metal carbonyl cluster complexes onto high surface area supports. Following a subsequent reduction, the precursor bimetallic cluster complexes are decomposed on the support surface forming a potassium (or rubidium) promoted Group VIII-metal cluster catalyst in which the potassium (or rubidium) and Group VIII metals are intimately associated. These unique, highly promoted cluster catalysts have been found to demonstrate high Group VIII-metal dispersions and enhanced Fischer-Tropsch activities and selectivities for producing olefinic and paraffinic hydrocarbons. In addition methane formation is dramatically reduced over the supported bimetallic cluster catalysts of the instant invention when compared to conventionally prepared supported potassium (or rubidium) promoted Group VIII-metal catalysts.
Supported, highly dispersed, high activity potassium or rubidium-Group VIII metal cluster catalysts demonstrating improved selectivity to olefinic and paraffinic hydrocarbons in CO/H.sub.2 reactions prepared by the process which comprises depositing known, well-characterized potassium or rubidium-Group VIII metal carbonyl cluster complexes and mixtures thereof on a high surface area support material, drying the carbonyl cluster complex impregnated support in the absence of oxygen, and reducing the supported complex at elevated temperatures to effect the essentially complete reduction of the supported potassium or rubidium-Group VIII metal carbonyl cluster complexes to discrete potassium or rubidium-Group VIII clusters of metals on the support surface.
A method for the preparation of supported potassium or rubidium Group VIII metal cluster catalysts which comprises depositing known, well characterized potassium or rubidium-Group VIII metal carbonyl cluster complexes and mixtures thereof, on a high surface area support material, drying the carbonyl cluster complex impregnated support in the absence of oxygen, and reducing the supported complex at elevated temperatures to effect the essentially complex reduction of the supported potassium or rubidium-Group VIII metal carbonyl cluster complexes to discrete potassium or rubidium-Group VIII clusters of metals on the support surface.
Dependencies are inferred from the claim text.