OXIDATIVE DEHYDROGENATION OF NORMAL-BUTANE TO BUTADIENE - EFFECT OF DIFFERENT PROMOTERS ON THE PERFORMANCE OF VANADIUM MAGNESIUM-OXIDE CATALYSTS

A detailed study has been performed on the effect of different promoters viz. Cr2O3, MoO3 and TiO2, which are added to vanadium-magnesium oxide (V-Mg-O) catalyst used for the production of butadiene from n-butane via oxidative dehydrogenation. The results are compared with those obtained from unpromoted V-Mg-O catalyst. It was found that Cr2O3 and MoO3 Promoters enhanced the activity of the catalyst, while TiO2 enhanced the selectivity. Finally, a fifth V-Mg-O catalyst containing both Cr2O3 and TiO2 as promoters was prepared and the reaction was studied in detail over this catalyst. A maximum yield of butadiene of 35.5 mol-% was obtained with this catalyst. Electron paramagnetic resonance studies showed that VO2+ is the active species involved in the reaction. On comparison with the unpromoted V-Mg-O catalyst, it was found that V-Mg-O, Cr2O3, TiO2 gave a better yield of butadiene.