TH32608A - How to prepare for vinyl acetate catalyst By using alkali methosolate - Google Patents

Abstract

DC60 (10/06/40) A method for preparing catalysts for the synthesis of unsaturated esters, where the catalyst carrier is saturated with water-soluble palladium salts and water-soluble gold compounds, is followed by precipitation of the water-soluble palladium salts and water-soluble gold compounds into insoluble palladium and gold compounds by immobilization of a mixture containing alkali metal borate. The immobilized palladium and gold compounds are reduced to metallic palladium and gold using ethylene or hydrazine, followed by saturated carriers with alkali metal acetate such as potassium acetate. These unsaturated ester catalysts can also be used to synthesize vinyl acetate with a strong reduction of the final product. The method for preparing catalysts for the synthesis of unsaturated esters, where the catalyst carrier is saturated... Immersion with water-soluble palladium salts and water-soluble gold compounds was followed by precipitation of the water-soluble palladium salts and gold compounds into insoluble palladium and gold compounds by immobilizing the mixture with alkali metal borate. The immobilized palladium and gold compounds were reduced to metallic palladium and gold using ethylene or hydrazine, followed by immobilization with alkali metal acetate such as potassium acetate. Catalysts used in the synthesis of unsaturated esters can be used to synthesize vinyl acetate with a strong reduction of the final product.

Claims (24)

1. The method for preparing unsaturated ester catalysts involves saturating the catalyst carrier with water-soluble palladium and gold compounds; immobilizing the water-soluble palladium and gold compounds onto the carrier; forming insoluble palladium and gold compounds using an immobilization mixture containing an alkali metal borate solution; and reducing the insoluble palladium and gold compounds to metallic palladium and gold to form the catalyst. 2. The method of claim 1 shall consist of a moistened carrier being rolled back and forth in an alkali metal borate solution by rotation to precipitate water-soluble palladium compounds into insoluble palladium compounds and to precipitate water-soluble gold compounds into completely insoluble gold compounds. 3. Method of Claim 2, in which the carrier, immersed in an alkaline metal borate solution, is rotated from approximately 1 to approximately 10 rpm for approximately 0.5 to approximately 4 hours. 4. The method of claim 1 in which insoluble palladium compounds and insoluble gold compounds are reduced to palladium metal and to gold metal by a reducing agent containing ethylene or hydrazine. 5. The method of claim 4 involves the reducing agent being hydrazine and the molar ratio of hydrazine to palladium and gold metal being approximately 10:1 to approximately 15:1. 6. Method of claim 5, where the molar ratio of hydrazine to palladium and gold is approximately 12:1. 7. The method of claim 5 shall consist of washing and drying the carrier after reducing the insoluble palladium and gold compounds to metallic palladium and gold. 8. Method of claim 7 where drying is at approximately 100°C in an inert atmosphere under a continuous flow of nitrogen. 9. Method of Claim 1 where aqueous-soluble compounds and aqueous-soluble compounds saturated on the carrier are immobilized on the carrier as insoluble palladium compounds and insoluble gold compounds by pouring an alkali methorborate solution onto the carrier at a volume equal to the dry adsorption capacity of the carrier. 10. The method of claim 1 involves immersing the carrier with alkali metal acetate. 11. Method of Claim 10 where alkali metal acetate is composed of potassium acetate, sodium acetate, lithium acetate, rubidium acetate or cesium acetate. 12. The method of claim 9 involves air that causes the carrier to be fixed after the immobilization of the water-soluble palladium and gold compounds. 13. The method of Claim 1 in which aqueous palladium compounds containing palladium chloride, sodium palladium chloride, potassium palladium chloride, palladium sulfate or palladium nitrate 14. Method of Claim 1 where aqueous gold compounds contain sodium or potassium salts of auric chloride or tetrachlorouric acid. 15. Method of Claim 1 where alkali metal borate consists of sodium tetraborate, sodium tetraborate pentahydrate, sodium tetraborate decahydrate, potassium tetraborate, potassium tetraborate pentahydrate, or potassium tetraborate decahydrate. 16. Method of Claim 1 in which the amount of palladium metal is added to a carrier containing a concentration of approximately 1.0 gm/l to approximately 10 gm/l. 17. Method of Claim 1 in which the amount of gold metal is added to a carrier containing a concentration from approximately 0.5 gm/l to approximately 10 gm/l. 18. Method of Claim 1, in which the amount of gold metal added to the carrier is 3.0 gm/l and the amount of palladium metal is approximately 6.6 gm/l. 19. Method of Claim 1 in which the amount of gold metal added to the carrier is approximately 4.0 gm/l and the amount of palladium metal is approximately 7.0 gm/l. 20. Method of Claim 1 where the carrier is silica. 21. The method of Requisition 1 in which a water-soluble palladium compound is saturated onto a carrier and fixed to the carrier as an insoluble palladium compound, then reduced to palladium metal before being saturated with a water-soluble gold compound. 22. The procedure of claim 21, which involves the immersion of the carrier in an alkali metal borate solution and a water-soluble gold compound, will immobilize the water-soluble gold compound on the carrier as an insoluble gold compound. 23. The method of claim 22, which involves the steps of reducing the insoluble gold compound to metallic gold. 24. The method of claim 1, where the molar ratio of alkali metal borate to palladium and gold in water-soluble compounds is approximately 1.5:1 to 2.5:1 (Clause 24, page 3, figure 0).