Multinuclear Solid-State NMR Characterization of the Coke on Mo/H beta-Al2O3 Catalyst for Olefin Metathesis

Multinuclear solid-state C-13, Al-27, and Si-29 MAS NMR and Xe-129 NMR were used to study the carbon deposition on the 6%Mo/H beta-Al2O3 catalyst in metathesis of ethene and 2-butene to propene. The results showed that the coke composition was aliphatic hydrocarbons, and the most of them was present in H beta zeolite instead of in Al2O3. The Xe-129 NMR experiments clearly revealed that the deposited carbon was located at the positions of channel intersections in H beta zeolite, which caused the deactivation of the catalyst.