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US 2003/0171611 A1Published application
De-oxygenation treatment for noble metal on carbon catalysts used in liquid phase oxidation reactions
AssigneeMonsanto Technology LLC
InventorMark A. Leiber
Life of this patent
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Abstract
A treatment for de-oxygenating a noble metal on carbon catalyst used in liquid phase oxidation reactions which includes exposing the catalyst to a non-oxidizing environment. The de-oxygenation treatment improves catalyst performance and is particularly suited for noble metal on carbon catalysts used to catalyze the oxidative cleavage of a carboxymethyl substituent from an N-(phosphonomethyl)iminodiacetic acid substrate in an aqueous reaction mixture using an oxygen-containing gas to produce an N-(phosphonomethyl)glycine product. In one embodiment, the catalyst is exposed to a non-oxidizing environment by introducing a non-oxidizing gas and/or reducing gas into a slurry comprising the catalyst in contact with a liquid medium.
Claims51
A process for oxidizing a reagent, the process comprising:
- contacting an aqueous reaction mixture comprising the reagent and a heterogenous oxidation catalyst with an oxygen-containing gas in an oxidation reaction zone to oxidize the reagent and produce an aqueous reaction product mixture comprising the oxidized reagent and the oxidation catalyst and having oxygen dissolved therein, the oxidation catalyst comprising a noble metal deposited on a carbon support;
- separating at least a portion of the oxidized reagent from the reaction product mixture to form a product fraction comprising the separated oxidized reagent substantially free of the oxidation catalyst and a catalyst slurry fraction comprising the oxidation catalyst in contact with a liquid medium having oxygen dissolved therein;
- subjecting the catalyst slurry fraction to a de-oxygenation treatment to reduce the dissolved oxygen concentration in the catalyst slurry fraction;
- and
- recycling and introducing the de-oxygenated catalyst slurry fraction into the oxidation reaction zone.
2 more elements
A process for the preparation of an N-(phosphonomethyl)glycine product, the process comprising:
- contacting an aqueous reaction mixture comprising an N-(phosphonomethyl)iminodiacetic acid substrate and a heterogenous oxidation catalyst with an oxygen-containing gas in an oxidation reaction zone to oxidize the N-(phosphonomethyl)iminodiacetic acid substrate and produce an aqueous reaction product mixture comprising the N-(phosphonomethyl)glycine product and the oxidation catalyst, the oxidation catalyst comprising a noble metal deposited on a carbon support;
- filtering the reaction product mixture to separate at least a portion of the N-(phosphonomethyl)glycine product from the reaction product mixture and form a filtrate product fraction comprising the separated N-(phosphonomethyl)glycine product substantially free of the oxidation catalyst and a catalyst slurry fraction comprising the oxidation catalyst in contact with a liquid medium;
- subjecting the catalyst slurry fraction to a de-oxygenation treatment, the de-oxygenation treatment comprising exposing the catalyst slurry fraction to a non-oxidizing environment comprising a non-oxidizing gas by introducing the non-oxidizing gas into a vessel containing the catalyst slurry fraction in a manner such that the non-oxidizing gas introduced into the vessel passes through the catalyst slurry fraction;
- and
- recycling and introducing the de-oxygenated catalyst slurry fraction into the oxidation reaction zone.
2 more elements
A process for oxidizing a reagent, the process comprising:
- contacting an aqueous reaction mixture comprising the reagent and a heterogenous oxidation catalyst with an oxygen-containing gas in an oxidation reaction zone to oxidize the reagent and produce an aqueous reaction product mixture comprising the oxidized reagent and the oxidation catalyst, the oxidation catalyst comprising a noble metal deposited on a carbon support;
- subjecting a catalyst slurry comprising the oxidation catalyst in contact with a liquid medium to a de-oxygenation treatment, the de-oxygenation treatment comprising exposing the catalyst slurry to a non-oxidizing environment comprising a reducing gas;
- and
- recycling and introducing oxidation catalyst obtained in the de-oxygenated catalyst slurry into the oxidation reaction zone.
1 more element
A process for the preparation of an N-(phosphonomethyl)glycine product, the process comprising:
- contacting an aqueous reaction mixture comprising an N-(phosphonomethyl)iminodiacetic acid substrate and a heterogenous oxidation catalyst with an oxygen-containing gas in an oxidation reaction zone to oxidize the N-(phosphonomethyl)iminodiacetic acid substrate and produce an aqueous reaction product mixture comprising the N-(phosphonomethyl)glycine product and the oxidation catalyst, the oxidation catalyst comprising a noble metal deposited on a carbon support;
- filtering the reaction product mixture to separate at least a portion of the N-(phosphonomethyl)glycine product from the reaction product mixture and form a filtrate product fraction comprising the separated N-(phosphonomethyl)glycine product substantially free of the oxidation catalyst and a catalyst slurry fraction comprising the oxidation catalyst in contact with a liquid medium;
- subjecting the catalyst slurry fraction to a de-oxygenation treatment, the de-oxygenation treatment comprising exposing the catalyst slurry fraction to a non-oxidizing environment comprising a reducing gas by introducing the reducing gas into a vessel containing the catalyst slurry fraction in a manner such that the reducing gas introduced into the vessel passes through the catalyst slurry fraction;
- and
- recycling and introducing the de-oxygenated catalyst slurry fraction into the oxidation reaction zone.
2 more elements
Dependencies are inferred from the claim text.