The Reaction of Cyclopropane with Deuterium

It very soon became clear that the products of the reaction of cyclopropane with deuterium could be explained by supposing a low concentration of propyl radicals and a high concentration of deuterium atoms on the metal surfaces, their 

On films of the metals of Group 10, rhodium, iron and tungsten, the cyclopropane-deuterium reaction gave product distributions in line with those found with the pumice-supported metals where comparison is possible nickel and particularly iron gave much multiply-exchange propanes. The kinetic parameters are given in Table 11.2. 

Very slight exchange of the hydrogens in cyclopropane was noted on Rh/pumice and Ir/pumice it appeared to be substantial on rhodium film at 173 suggesting that it is a low activation energy process. It also occurred significantly on tungsten film.  

More recently the reaction has been examined over silica-supported rhodium, palladium, iridium and platinum, with the help of NMR spectroscopy. The results were much in line with those already mentioned, the amounts of propane-dg increasing in the sequence Pt Ir Rh Pd. Thepropane-d2 was not surprisingly mainly propane-l,3-t/2. A new feature was observed with Ir/A Os the support made a significant contribution to the overall reaction, and this necessitated a revision of a previous interpretation of the activity of this metal in alkane exchange.  

Discussion of the mechanisms involved in the reactions of cyclopropane with hydrogen and deuterium is relatively straightforward because of the evident similarity if not identity of unit steps with those encountered in the reactions of alkanes (Chapters 6,13 and 14). This has not however inhibited scientists from suggesting a variety of possible intermediate adsorbed species. 

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