TH14913B - Catalysts for vinyl acetate production. - Google Patents

Abstract

Catalysts, for example, those used for the production of vinyl acetate from acetic acid, ethylene, and oxygen, are assembled with palladium, gold, and other metals from the zirconium and rhenium groups on a porous support. These catalysts are produced by the adsorption of water-soluble metal salts onto the support, the precipitation of the metals as insoluble salts, and the reduction of the salts back into metals.

Claims (9)

1. A method for preparing useful catalysts for vinyl acetate production in the gaseous phase from acetic acid, ethylene, and oxygen, consisting of a porous support deposited with palladium (approximately 2 to 14 g/L), gold (approximately 1 to 8 g/L), and at least one zirconium metal (approximately 0.5 to 4 g/L), and rhenium (approximately 1 to 8 g/L). This method includes: immersing the support with water-soluble metal compounds; converting the water-soluble metal compounds into insoluble metal compounds by immersing the immersed support in an immobilizer solution containing a reactive compound with the water-soluble compounds; and precipitating the insoluble metal compounds on the support while immersing the immersed support in the immobilizer solution. Shake the moistened support for sufficient time to evenly coat it with the immobilizing solution, ensuring complete precipitation of the aforementioned insoluble compounds. Rinse the support and reduce the insoluble metal compounds to create free metal on the support. 2. The method of claim 1, in which the catalyst consists of a porous support with metals including palladium from approximately 2 to approximately 14 g/L, gold from approximately 1 to approximately 8 g/L, and zirconium from approximately 0.5 to approximately 4 g/L deposited on it. 3. The method of claim 1, in which the catalyst consists of a porous support with metals comprising palladium from approximately 2 to approximately 14 g/L, gold from approximately 1 to approximately 8 g/L, and rhenium from approximately 1 to approximately 8 g/L deposited on it. 4. The method of claim 1, in which the catalyst consists of a porous support containing metals in combination with palladium from approximately 2 to approximately 14 g/L, gold from approximately 1 to approximately 8 g/L, and zirconium from approximately 0.5 to approximately 4 g/L, and rhenium from approximately 1 to approximately 8 g/L, deposited on it. 5. Method for preparing a useful catalyst for vinyl acetate production in the gaseous phase from acetic acid, ethylene, and oxygen, consisting of a porous support deposited on it containing palladium (approximately 2 to 14 g/L), gold (approximately 1 to 8 g/L), and at least one zirconium metal (approximately 0.5 to 4 g/L), and rhenium (approximately 1 to 8 g/L). Contact of the support with at least one of the aforementioned water-soluble metal compounds is then performed to saturate the support with these soluble compounds. The water-soluble metal compounds are then converted into insoluble metal compounds by contact of the saturated support in the first immobilization step with a solution containing the reactive compounds with the water-soluble compounds, leading to the precipitation of the insoluble metal compounds onto the support. The contact of the first, immobilized and fixed support, as mentioned, with at least one more, atomically soluble compound of the metal, is performed to saturate the support with the aforementioned water-soluble compound. The second, water-soluble compound of the metal is then converted into an insoluble metal compound by contact of the first, immobilized support in a second solution containing the reactive compound with the second, water-soluble compound. This causes the precipitate of the second, insoluble metal compound onto the support. Subsequently, the insoluble metal compound is reduced to produce the free precious metal on the support. 6. The method of claim 5, in which the catalyst consists of a porous support with metals comprising palladium from approximately 2 to approximately 14 g/L, gold from approximately 1 to approximately 8 g/L, and zirconium from approximately 0.5 to approximately 4 g/L deposited on it. 7. The method of claim 5, in which the catalyst consists of a porous support containing metals in combination with palladium from approximately 2 to approximately 14 g/L, gold from approximately 1 to approximately 8 g/L, and rhenium from approximately 1 to approximately 8 g/L deposited on it. 8. The method of claim 5, in which the catalyst consists of a porous support containing metals in combination with palladium from approximately 2 to approximately 14 g/L, gold from approximately 1 to approximately 8 g/L, and zirconium from approximately 0.5 to approximately 4 g/L, and rhenium from approximately 1 to approximately 8 g/L, deposited on it. 9. The use of catalysts prepared by the method of one of the preceding claims for the production of vinyl acetate from acetic acid, ethylene, and oxygen.