摘要 |
<p>VPO catalysts are new when obtained by reacting vanadium pentoxide with concentrated phosphoric acid in an organic medium under reflux; separating off the catalyst pre-form and optionally drying at 80-140[deg]C; impregnating the pre-form with an aqueous or alcoholic solution of a specified metal; separating off the excess of the solution; and drying and calcining the resulting material and optionally forming the catalyst. VPO catalysts of formula (I) are new when obtained by (a) reacting vanadium pentoxide with concentrated phosphoric acid in an organic medium under reflux; (b) separating off the catalyst pre-form and optionally drying at 80-140[deg]C; (c) impregnating the pre-form with an aqueous or alcoholic solution of a metal X; (d) separating off the excess of the solution; and (e) drying and calcining the resulting material and optionally forming the catalyst. [V 1P aX b(Y) cO d] e[Z] f(I) a : 0.1-2.5; b : 0-3.0 (especially 0.001-3.0); c : 0.1-10; d depends on the valency of the other elements; e = 5-100; f = 95-0 (especially 95-5) with the proviso that b and f are not both 0; X = chromium, molybdenum, tungsten, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, zinc or niobium; Y = a cyclic nitrogen compound; and Z =silicon dioxide, aluminum oxide (Al 2O 3), zirconium dioxide and/or titanium dioxide.</p> |