A Study of the Partial Catalytic Oxidation of Hydrocarbons. V. The Effect of Phosphorus Addition to the Vanadium Catalyst on the Oxidation of Butene, Butadiene, and Furan

In the present investigation, the vapor-phase partial oxidation of cis-2-butene, butadiene, and furan was carried out over V2O5 and V2O5-P2O5, (1 : 1.6 atomic ratio), with various contact times, at 350°C, and at the concentration of 0.6–1.6% in air, in order to elucidate the effect of phosphorus addition to V2O5, on the selectivity and mechanism of butene oxidation. Oxidation activity decreased remarkably with an increase in the phosphorus content. In the presence of phosphorus (P/V=1.6), selectivity for the C4H8→C4H6 step and C4H6→C4H4O step were considerably increased, from 46 to 88 and from 72 to 93 mol% respectively, while selectivity for the C4H4O→maleic anhydride (MA) step fell from 60 to 50 mol%, due to the increase in polymer formation. From the results, it was concluded that V2O5 and V2O5-P2O5 catalysts show similar oxidation activity with regard to butene, butadiene, and furan, and that the quantities of the intermediate products are fairly much affected by the activity of the catalyst as well as by the difference in reactivity between the starting material and the intermediate over the catalyst.