Thermocatalytic dehydrogenation of alkanes with Wilkinson complexes

Abstract

Under boiling and refluxing conditions, molecular hydrogen was evolved was evolved catalytically, without photoirradiation, from cyclo- and n-alkanes using Wilkinson complexes. In the presence of hydrogen acceptors such as alkenes, hydrogen transfer rather than hydrogen evolution occurred. The rates of both reactions using the Wilkinson complex [RhCl(PR₃)₃], R = aryl, were comparable, however, when R = alkyl, the rate of hydrogen evolution was reduced more effectively than that of hydrogen transfer. The mechanisms of the thermocatalytic dehydrogenation of the alkanes using these complexes are discussed in terms of electron-accepting or -donating ligand properties.