SUPPRESSION OF AGING FOR PD-AU VINYL ACETATE MONOMER CATALYST

摘要

One aspect of the present invention relates to a method of making vinyl acetate monomer, involving contacting reactant gases with a catalyst containing palladium, gold and a support in the presence of clean steam, the clean steam present from about 2 to about 10 psia, with the proviso that the support does not contain alumina or zinc oxide and the support is not treated with a sulfur containing compound. For example, the method of making vinyl acetate monomer may involve the reaction scheme: O2+H2O+CH2CH2+CH3CO2H-CH3CO2CH=CH2+H2O.Another aspect of the present invention relates to a method of regenerating a palladium-gold catalyst having an alumina-silica support during a process for making vinyl acetate monomer, with the proviso that the support does not contain alumina or zinc oxide and the support is not treated with a sulfur containing compound, involving temporarily stopping the process for making vinyl acetate monomer; contacting a gas mixture containing at least oxygen with the palladium-gold catalyst in the presence of clean steam at a temperature from about 100 DEG C. to about 180 DEG C., the clean steam present from at least about 2 psia and the oxygen present from at least about 2 psia; and restarting the process for making vinyl acetate monomer.