Preparation of palladium-gold catalyst
View Patent ↗A method for preparing a palladium-gold catalyst containing a titania extrudate is disclosed. The titania extrudate is produced by using a carboxyalkyl cellulose and a hydroxyalkyl cellulose as extrusion aids. The titania extrudate has improved processibility and/or mechanical properties. After calcination, the extrudate is used as a carrier for the palladium-gold catalyst. After calcination, the in producing vinyl acetate by oxidizing ethylene with oxygen in the presence of acetic acid.
1. A method for preparing a palladium-gold catalyst comprising (a) mixing titania, a carboxyalkyl cellulose, and a hydroxyalkyl cellulose to form a dough; (b) extruding the dough to produce an extrudate; and (c) calcining the extrudate to produce a calcined extrudate; (d) impregnating the calcined extrudate with a palladium compound and a gold compound to produce an impregnated extrudate; and (e) calcining the impregnated extrudate to produce the palladium-gold catalyst; wherein the weight ratio of the carboxyalkyl cellulose to the titania is from 1:100 to 3:100.
2. The method of claim 1 further comprising reducing the palliadium-gold catalyst to produce a reduced catalyst.
3. The method of claim 2 wherein the palladium-gold catalyst is reduced by hydrogen.
4. The method of claim 3 further comprising adding an activator to the reduced catalyst to produce a promoted palladium-gold catalyst.
5. The method of claim 1 wherein the titania is anatase.
6. The method of claim 1 wherein the weight ratio of the hydroxyalkyl cellulose to the titania is from 0.5:100 to 1:100.
7. The method of claim 1 wherein the weight ratio of the carboxyalkyl cellulose to the hydroxyalkyl cellulose is from 3:1 to 1:1.
8. The method of claim 1 wherein the hydroxyalkyl cellulose is selected from the group consisting of methyl 2-hydroxypropyl cellulose, methyl 2-hydroxethyl cellulose, and mixtures thereof.
9. The method of claim 1 wherein the extrudate is calcined at a temperature of 650 to 750° C.