Controlled preparation of Pd/AC catalysts for hydrogenation reactions

A commercial activated carbon was submitted to different liquid oxidizing treatments in order to create a high density of carboxylic groups on the carbonaceous surface. Characterization of the modified activated carbon shows that it is possible to generate a large range in acidic group concentration without significant change of the textural properties. This ability allows us to introduce, by ion exchange, palladium cations up to 7.3 wt.%. This way of preparation, coupled to soft formaldehyde reduction, leads to highly dispersed metallic palladium catalysts. The resulting catalysts were tested in hydrogenation of cinnamaldehyde and exhibited a high hydrogenation efficiency compared to activities reported in the literature.