Evaluation of the mechanism of the oxy-dehydrogenation of propane over manganese oxide

The oxidation of propane over a Mn(3)O(4) catalyst has been investigated with oxygen to propane ratios up to 2:1. High selectivities to the oxy-dehydrogenation product propene have been obtained at low conversions, with yields up to 5% and productivities up to above 1.5 Kg(C3H6)/Kg(cat) h. Data on the mechanism and on the reaction pathways have been derived from an evaluation of the reaction kinetics and from FT-IR experiments. The main by-reaction with respect to oxy-dehydrogenation is propene over-oxidation to CO(2). Direct total oxidation of propane to CO(2) can become predominant only in oxygen excess. Isopropoxide species act probably as surface intermediate species in propene synthesis. (C) 1998 Elsevier Science B.V. All rights reserved.