On the specific activity of platinum catalysts

The specific activity for hydrogenation of cyclopropane at 0 °C on platinum catalysts was found to be independent of platinum content on two different forms of alumina, independent of the nature of the support with alumina or silica gel, and almost the same for highly dispersed samples in which nearly every platinum atom is a surface atom as for a platinum foil. The difference between the highly dispersed samples and the others (sintered, less dispersed, foil) was a modest twofold change in specific activity, while the platinum specific surface area varied by more than four orders of magnitude. In contradistinction, a very marked susceptibility to oxygen poisoning was found for the well-dispersed catalysts that was not observed for the other samples.