Vinyl acetate catalyst preparation method
AssigneeHoechst Celanese Corporation
InventorPhilip M. Colling
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Abstract
A method of preparing a catalyst particularly useful in the reaction of ethylene, oxygen and acetic acid in the vapor phase to form vinyl acetate comprises impregnating a porous support with water soluble salts of palladium and gold, fixing the palladium and gold on the support as water insoluble compounds by contacting the salt-impregnated support with a reactive solution in two separate fixing stages wherein the treated support is dried and allowed to stand prior to treatment in the second stage to precipitate the insoluble compounds on the support and reducing the insoluble compounds to free palladium and gold. The catalysts prepared in this manner have been shown to provide improvement with respect to reduced selectivity to CO.sub.2 during the vinyl acetate forming reaction.
Claims12
In a method of preparing a catalyst composed of a porous support containing thereon precious metals comprising;
- impregnating said support with water soluble compounds of said precious metals, converting said water soluble precious metal compounds to water insoluble precious metal compounds by contacting said impregnated support with a water soluble compound to precipitate an insoluble precious metal compound on said support, and reducing said water insoluble precious metal compounds with a reducing gas to form free precious metals on said support, the improvement which comprises converting the precious metal to an insoluble precious metal compound in two steps, a first fixing stage with a solution containing a compound reactive with said water soluble precious metal compounds to precipitate on said support said water insoluble precious metal compounds, then contacting said supports with additional solution containing a compound reactive with said water soluble compounds in a second fixing stage to further precipitate on said support said water insoluble precious metal compounds.
Dependencies are inferred from the claim text.