13 C MAS NMR mechanistic study of the initial stages of propane activation over H-ZSM-5 zeolite

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13C MAS NMR study of the early stages of propane 2-13C activation was performed over H-ZSM-5 catalysts with various content of protonic and aprotonic sites. The reaction mechanism was tested by addition of various probe-molecules (C3H6, C6H6, H2, H2O and CO). The results on tracing the fate of 13C label during this experiments conclude to a monofunctional mechanism involving propane protonation on the strong Bronsted sites of H-ZSM-5 and the formation of carbonium ion type transition states, which further evolve in four different ways leading to 13C scrambling in propane, cracking, dehydrogenation and disproportionation.