13C MAS NMR mechanistic study of propane conversion into butanes over H-MFI catalyst

I.I. Ivanova, A.I. Rebrov, E.B. Pomakhina, and E.G. Derouane

J. Mol. Catal. A: Chemical, v.141, p. 107-116 (1999)

ABSTRACT. 13C MAS NMR was performed under controlled atmosphere to investigate the mechanism of propane conversion into butanes over H-MFI catalyst. Propane 2-13C was labelled reactant, surface coverages being varied from 0,5 to 4 molecules per unit cell. The nature of primary labelled products observed upon propane conversion was found to depend on propane partial pressure in the system. High pressures of propane enhance bimolecular disproportionation leading to ethane and both butane isomers. Low pressures favor formation of the only i-butane. The detailed mechanistic pathways are discussed to account for both high pressure and low pressure observations. The proposed mechanisms are tested by addition of various probe-molecules (C3H6 2-13C, C6H6, H2, H2O and CO).

Laboratory of Kinetics and Catalysis