| abstract |
A method for regenerating used supported noble metal catalysts, which method includes solvent cleaning the used catalyst by contact with a suitable organic liquid cleaning solvent such as alcohols, ketones and such to remove organic deposits from the catalyst, followed by drying and calcining at elevated temperature to remove any remaining organic deposits from the catalyst, then treating the catalyst with an organo-metallic complex forming agent having ionization constant pK1 greater than about 2.5, such as glycolic acid and the like. The organic-metallic complex forming agent acts to break down large clusters of noble metal particles such as palladium (Pd) and redistributes the metal particles on the catalyst support such as alumina (Al2O3) in the same or other larger pores, so as to increase catalyst surface area and catalytic activity to provide a catalytic activity level at least 80% or even exceeding that of the fresh catalyst. This regeneration method is particularly useful for regenerating used supported palladium catalysts utilized for hydrogenation of ethyl anthraquinone (EAQ) for producing hydrogen peroxide (H2O2) product. |