Oxidative dehydrogenation of n-pentane on magnesium vanadate catalysts

Two pure magnesium vanadate phases, Mg2V2O7 and Mg3V2O8, were prepared and tested in the dehydrogenation of n-pentane in the presence of oxygen. Both magnesium vanadates are effective catalysts, with Mg3V2O8 exhibiting higher selectivity to dehydrogenation products. Testing of mechanical mixtures, consisting of each one of the magnesium vanadates and antimony oxide, indicated that the latter had a positive effect especially on the selectivity to dehydrogenation with the Mg3V2O8 containing samples. The main products of the reaction were pentenes, pentadienes and carbon oxides. Characterisation of the samples prior to and after catalytic tests revealed that all catalysts remained practically unchanged during the reaction. The mixtures consisted of separate magnesium vanadate and antimony oxide phases and no formation of new phases was detected.