Preparation of chlorine dioxide with platinum group metal oxide catalysts
AssigneeDiamond Shamrock Corporation
InventorsKenneth L. Hardee, Arnold Z. Gordon, Charles B. Pyle, Rajat K. Sen
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Abstract
A catalyst together with a catalytic method for making chlorine dioxide from an acid and a metal chlorate solution. The catalyst generally comprises at least one of a valve metal oxide, ruthenium oxide, iridium oxide, palladium oxide, platinum oxide and rhodium oxide.
Claims18
A process for the generation of ClO.sub.2 comprising the steps of:
- (1) providing a chlorate containing feedstock selected from a group consisting of aqueous solutions of alkali metal chlorates and alkaline earth metal chlorates;
- (2) providing an acid feedstock;
- (3) providing a catalyst comprising a mixture of a valve metal oxide and at least one of ruthenium oxide, iridium oxide, palladium oxide, rhodium oxide and platinum oxide;
- (4) combining the feedstocks and reacting the combined feedstocks in contact with the catalyst at a temperature greater than 20.degree. C.;
- and
- (5) stripping and recovering ClO.sub.2 from the combined feedstocks.
A process for the generation of ClO.sub.2 comprising the steps of:
- (1) providing an aqueous mixture of an acid and a chlorate selected from a group consisting of alkali metal chlorates and alkaline earth metal chlorates;
- (2) contacting the aqueous mixture with a catalyst comprising a mixture of platinum group metal oxides selected from a group of mixtures consisting of ruthenium-rhodium, ruthenium-palladium, iridium-rhodium, iridium-platinum, palladium-rhodium, and ruthenium-rhodium-palladium, each platinum group constituent of the mixture being present in a mole ratio of not less than 0.01;
- (3) maintaining the catalyst and aqueous mixture at a temperature greater than 20.degree. C.;
- and
- (4) stripping and recovering ClO.sub.2 from the contacted mixtures.
A process for the generation of ClO.sub.2 comprising the steps of:
- (1) providing an aqueous mixture of H.sub.2 SO.sub.4 and NaClO.sub.3 ;
- (2) contacting the aqueous mixture with a catalyst comprising a mixture of platinum group metal oxides selected from a group of mixtures consisting of ruthenium-rhodium, ruthenium-palladium, iridium-rhodium, iridium-platinum, palladium-rhodium, and ruthenium-rhodium-palladium, each platinum group constituent of the mixture being present in a mole ratio of not less than 0.01;
- (3) maintaining the catalyst and the aqueous mixture at a temperature greater than 20.degree. C.;
- and
- (4) stripping and recovering ClO.sub.2 from the contacted mixtures.
The method of claim 12 wherein the temperature is maintained at greater than 40.degree. C.
A process for the generation of ClO.sub.2 comprising the steps of:
- (1) providing a chlorate containing feedstock selected from a group consisting of aqueous solutions of alkali metal chlorates and alkaline earth metal chlorates;
- (2) providing an acid feedstock;
- (3) providing a catalyst comprising at least one of ruthenium oxide, iridium oxide, rhodium oxide and platinum oxide;
- (4) combining the feedstocks and reacting the combined feedstocks in contact with the catalyst at a temperature greater than 20.degree. C.;
- and
- (5) stripping and recovering ClO.sub.2 from the combined feedstocks.
Dependencies are inferred from the claim text.