摘要 |
<p>Hydrogenation catalysts comprising metallic palladium supported on activated carbon, wherein less than 50% by weight of the palladium is comprised within a surface layer with a depth of up to 50 microns, the remainder being comprised in a layer between 50 and 400 microns deep. The catalysts can be used in particular in purifying terephthalic acid obtained by oxidation of p-xylene. They are prepared by dry impregnation of the support.</p> |