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

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 Brønsted 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.