Noble metal catalysts are regenerated according to a process comprising the steps of washing the deactivated catalyst with a polar organic solvent; contacting the washed catalyst with a hot aqueous alkali metal hydroxide solution; contacting the catalyst with an oxygen-containing gas at moderately elevated temperatures; and washing the catalyst a final time with a polar organic solvent. This method of regenerating the catalyst is particularly useful to reactivate palladium on carbon catalysts deactivated in the reduction of nitrophenol compounds to aminophenols.

Process of regenerating a noble metal catalyst used in the reduction of organic nitro compounds

A method for reactivation of a platinum group metal catalyst which comprises treating the platinum group metal catalyst lowered in catalytic activity as the result of having been used for the catalytic reaction of hydrocarbons optionally containing an oxygen atom with at least one agent selected from an inorganic alkaline substance and a reducing substance in an aqueous medium.

Method for reactivation of platinum group metal catalyst with aqueous alkaline and/or reducing solutions

Nitrogen compounds are removed from liquid hydrocarbons such as oils of lubricating viscosity by contacting the hydrocarbons with a solid sorbent, having anhydrous acid gas adsorbed therein. The solid sorbent, which may be amorphous, e.g. silica-alumina, or crystalline, e.g., NaX, is thereafter regenerated for reuse.

Process for the removal of nitrogen compounds from various organic media

Residues are formed in the carbonylation of esters or ethers, particularly in the production of acetic anhydride or ethylidene diacetate. Such residues contain noble metal, typically rhodium used as a catalyst, which must be recovered before the residues can be disposed of. In the process of the invention, the rhodium values are freed from the residues by a series of treatments with amines and other reagents, thereby enabling the rhodium to be extracted by subsequent contact with an aqueous halogen acid.

Recovery of rhodium from carbonylation residues

A process for recovering rhodium present in a still heel from the hydroformylation of an unsaturated hydrocarbon wherein rhodium and a triaryl phosphite ligand were used by a process comprising (a) pretreating the still heel with a compatible organic solvent or a mixture thereof, at least 5 ml of water per 100 g of still heel, oxygen gas or a precursor thereof and sufficient base to produce a pH of 2 to 7 in the reaction mixture after rhodium precipitation; (b) heating to a temperature of from 0° to 80° C to oxidize the triaryl phosphite ligand to the corresponding phosphate compound; (c) heating the mixture from (b) for from about 15 minutes to about 120 minutes at about 115° C to about 175° C to precipitate zero valent rhodium; and optionally purifying the precipitated rhodium from (c) by (d) separating the rhodium precipitate; (e) washing the rhodium precipitate with a solvent-acid solution at a pH of 3 to 4; (f) treating the rhodium precipitate with an alkaline reducing solution to reduce the trivalent rhodium impurity to zero valent rhodium; (g) quenching the rhodium with glacial acetic acid; (h) separating the rhodium; (i) washing the rhodium with an acid solution at a pH of 3 to 4; (j) drying the rhodium in an inert atmosphere at from 250° to 400° C; and (k) oxidizing the rhodium at a temperature of from 300° to 900° C to convert the rhodium to Rh 2 O 3 .

Rhodium recovery from hydroformylation still heel with triaryl phosphite ligand

This invention describes a process for regenerating deactivated noble metal hydrogenation catalysts to restore their catalytic activity The process involves contacting a deactivated noble metal hydrogenation catalyst with a polar organic solvent, then contacting the solvent-treated catalyst with an aqueous ammonium hydroxide solution followed by contacting the ammonium hydroxidetreated catalyst with steam and an oxygen-containing gas at temperatures from about 250*C to the transition temperature of the catalyst crystal structure whereby the catalytic activity of the catalyst is substantially improved

Lee Nathan Dean

Papers

Process of regenerating a noble metal hydrogenation catalyst used in hydrogen peroxide production by the anthraquinone process