Catalysis on metals of group 8. Part 4. The reaction of cyclopropane and of propane with deuterium over a platinum catalyst

Abstract

Initial propane distributions from the reaction of cyclopropane with deuterium over a platinum catalyst have been obtained at 50, 100 and 200" C, and the results compare well with those of a previous study. Initial distributions from the reaction of propane with deuterium over platinum at temperatures between 100 and 250" C are similar. In both cases, the deuterium content and the proportion of the contributing distribution which is predominant at high temperatures are temperature dependent.A brief comparative discussion of the behaviour of rhodium, palladium, iridium and platinum in these reactions is given. It is concluded that efficiency in multiple exchange runs parallel with catalytic activity for hydrogenation-type reactions, and that in group 8 metals horizontal relationships are more marked than vertical relationships.

The Hydrogenolysis of Dicyclopropylmethane on Nickel Catalysts

“…At 50°on rhodium, platinum, palladium, and iridium supported on pumice, the rate of formation of deuteriocyclopropanes, while finite, is much smaller than that of deuteriopropanes. 16 Further, the exchanged cyclopropanes are mostly diand trideuterioand this supports the occurrence of reaction B. Thus, all of these intermediates are plausible to some degree and there is the fearsome possibility that each may be significant at least with certain substituted cyelopropanes and under some particular set of conditions.…”

Hydrogenation of olefins. Part 1.—Hydrogenation of ethylene, propylene and the n-butenes over alumina-supported platinum and iridium

“…This paper treats the interaction of ethylene and of propylene with deuterium, and the hydrogenation, isomerization and exchange of the n-butenes, over aluminasupported platinum and iridium catalysts. At the start of this work in 1959, information on these reactions was largely confined to studies made with various kinds of nickel catalysts.3-8 Of the other metals of group 8, platinum was known to show little olefin exchange,g, 10 but apart from some fragmentary observations on palladium 11 and some measurements 2 on metal films under conditions far removed from those normally employed, nothing was known. However, during the course of this work, a number of relevant papers have appeared, and have been summarized in ref.…”

Catalytic exchange of n-hexane and deuterium and some allied reactions on films of palladium and rhodium

“…That for n-heptane on rhodium+ alumina 6 at 100" had a slight maximum at heptane-dl and the normal steep rise to heptane-dl6 and probably corresponds to a pure reaction of type B as would be expected at this temperature. The distributions for propane on rhodium+pumice 3 at temperatures between 50" and 200" showed pronounced maxima at propane-dl as well as greater maxima at propane-dg but these distributions can be reproduced 4 fairly satisfactorily by assuming a mechanism of type B involving interconversion between monoadsorbed, ap-diadsorbed and apy-triadsorbed species.…”