Study of the partial oxidation of propene by O2 and N2O over fixed Mo catalysts. Essential factors for catalysis and reaction mechanisms

Abstract

The partial oxidation of propene by O₂ and N₂O over fixed Mo catalysts with a well-defined structure of active sites was studied. The fixed catalysts had much higher activity than the impregnation catalysts. The co-ordinatively unsaturated dioxo-structure of Mo⁶⁺ ions [graphic omitted] uniformly and molecularly distributed in a tetrahedral position is an essential factor for the dehydrogenation activity. The OH and oxo-groups of [graphic omitted] made from [graphic omitted] during the reaction did not add to the allyl species to form acrolein. The tetrahedral dioxo-Mo⁶⁺ structure is also an active species for the oxidative double-bond scission of propene. These two reactions are competitive in the presence of O₂. The oxidation products depended upon the nature of the oxygen species. The reaction mechanisms are discussed.