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US 12,600,695 B2Granted
Method for reactivating a precious metal iron catalyst and performing a chemical reaction
AssigneeDow Global Technologies LLC
InventorsAdemola D. Idowu, Brian Cramm
Life of this patent
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Abstract
Catalytic activity of a spent precious metal-iron catalyst is restored by combining the spent catalyst with an iron (III) compound. This can be performed by adding the iron (III) compound into a chemical reaction that contains the spent precious metal-iron catalyst. It is unnecessary to add more of the precious metal. The process is especially useful in a continuous process for converting a nitro compound such as nitrobenzene to the corresponding amine.
Claims5
A process for producing an aromatic amine, comprising
- a) performing a continuous reduction reaction by continuously or intermittently introducing a starting nitroaromatic compound and hydrogen to a reaction vessel in the presence of a precious metal-iron catalyst supported on a carbonaceous support wherein the precious metal is palladium, platinum or a mixture of palladium and platinum and continuously or intermittently removing from the reaction vessel water and an aromatic amine produced by the reaction of the starting nitroaromatic compound and hydrogen, the reduction reaction being continued for a period of time such that the precious metal-iron catalyst becomes at least partially spent;
- b) thereafter adding an iron (III) compound one or more times to the reaction vessel while adding no more than 10% by weight of the precious metal, based on the weight of the iron in the added iron (III) compound wherein the iron (III) compound added is not supported and physically independent from the no more than 10% by weight of the precious metal, and
- thereafter continuing to perform the continuous reduction reaction in the presence of the at least partially spent precious metal-iron catalyst and the iron (III) compound.
Dependencies are inferred from the claim text.