Catalyst for hydrogenating anthraquinones

Claim 1

A method for making catalysts which are useful for the hydrogenation of anthraquinones comprising the sequential steps of a. impregnating dry activated alumina particles with 2-20 parts by weight of alkali metal carbonate or alkaline earth metal carbonate and 0.1-10 parts by weight of a basic palladium salt, said parts by weight being based on 100 parts by weight of dry activated alumina prior to impregnation, by admixing the alumina with finely divided particles of the palladium salt and an aqueous solution of the carbonate in which the amount of water is sufficient to wet the pores, but not the outer surface of the alumina, and allowing the impregnated alumina to stand for a time sufficient to complete diffusion of the palladium within the wetted pores of the catalyst; b. reducing the palladium by dispersing the impregnated alumina in a dilute aqueous solution of reducing agent, the amount of reducing agent being sufficient to reduce substantially all the palladium to a zero valence state; c. separating the reduced catalyst from the solution of reducing agent, washing it with water and then removing substantially all the water therefrom while maintaining the catalyst at a temperature below about 100° C; and d. heating the dewatered catalyst in an oxidizing atmosphere for a period of at least about 1 hour at a temperature of 400°-650° C.

Claim 2

A method for making catalysts which are useful for the hydrogenation of anthraquinones comprising the sequential steps of a. impregnating dry activated alumina particles with 2-20 parts by weight of alkali metal carbonate or alkaline earth metal carbonate and 0.1-10 parts by weight of a basic palladium salt, said parts by weight being based on 100 parts by weight of dry activated alumina prior to impregnation, by admixing the alumina with finely divided particles of the palladium salt and an aqueous solution of the carbonate in which the amount of water is sufficient to wet the pores, but not the outer surface of the alumina, and allowing the impregnated alumina to stand for a time sufficient to complete diffusion of the palladium within the wetted pores of the catalyst; b. reducing the palladium by dispersing the impregnated alumina in a dilute aqueous solution of reducing agent, the amount of reducing agent being sufficient to reduce substantially all the palladium to a zero valence state; c. separating the reduced catalyst from the solution of reducing agent, washing it with water and then removing substantially all the water therefrom while maintaining the catalyst at a temperature below about 100° C; and d. heating the dewatered catalyst in an oxidizing atmosphere for a period of at least about 1 hour at a temperature of 400°-650° C.