Dynamic Chemical Counting of Active Centers of Molybdena–Alumina Metathesis Catalysts

A dynamic method of chemical counting of active centers of alkene metathesis is proposed and applied to study MoO₃/Al₂O₃ and MoO₃/Al₂O₃-SnMe₄ systems. For the MoO₃/Al₂O₃ catalyst, the estimated number of the active sites is less than 1% of the total number of the Mo atoms. MoO₃/Al₂O₃-SnMe₄ catalysts have a larger percentage of active centers, compared with the system not treated with SnMe₄. This increase of the active sites number approximately corresponds to improvement of the metathesis activity of the MoO₃/Al₂O₃-SnMe₄ catalyst.