ACTIVITY OF V2O5 TIO2 MODIFIED BY PHOSPHO RUS IN THE OXIDATIVE DEHYDROGENATION OF ETHANE INTO ETHENE/

The present study deals with ethane dehydrogenation on V2O5/TiO2 modif ied by different amounts of P2O5. Catalysts containing P/V ratios rang ing from 0 to 3.3 were prepared by impregnation in presence of oxalic acid. Their characterization by various spectroscopic techniques showe d that in absence of phosphorus, the vanadium is essentially present i n the sample as V5+. Addition of P2O5 favors the formation of supporte d vanadyl phosphate and isolated V4+ species. Catalytic measurements h ave showed that phosphorus improves the selectivity towards ethene. At 550 degrees C, the total conversion reaches 33% and the selectivity 5 0%. The activity of the sample investigated seems to be governed by th e V5+/V4+ ratio. At higher concentration of V5+ like. in V2O5/TiO2 a g ood activity is achieved but the selectivity is poor. When the concent ration of V4+ is increased by an addition of P2O5 the selectivity incr eases.