| 摘要 |
<p>A palladium/carbon catalyst which exhibits high activity and long life in hydrogenation for aromatic functional groups, in particular, hydrogenation for an aromatic aldehyde group. According to the invention, a water solution of palladium salt is regulated in pH at the time of preparation of a catalyst whereby a proportion of palladium carried by a surface portion of a carbon carrier is large and a diameter of palladium grains on the surface portion is made larger than that of palladium grains carried in the interior of the carbon carrier. For example, in a catalyst for hydrogenation containing activated charcoal as a carrier and palladium as a main activated component, a cumulative pore volume of pores with diameters of 2 nm or less in the activated charcoal is selected to be at least 0.40 cm3/g and at most 0.55 cm3/g. Accordingly, initial activity is improved and long life is attained.</p> |
