Patent ID: 7589046
Filing Date: 2009-09-15
Classification: B01J,C07C,C21B,C22B,Y02P

Abstract:
1. A process for the thermal treatment of a precursor material of a catalytically active multi-element oxide material, comprising thermally treating the precursor material in a rotary tube furnace through which a gas stream flows at a material temperature of from 300° C. to 450° C. to form the catalytically active multi-element oxide material, wherein the catalytically active multi-element oxide material comprises the elements Mo, V, and at least one of the elements Nb and W, wherein the molar fraction of the element Mo in the catalytically active multi-element material, based on the total amount of all elements other than oxygen in the catalytically active multi-element oxide material, ranges from 20 mol % to 80 mol %, wherein the molar ratio of Mo to V in the catalytically active multi-element oxide material, Mo/V, ranges from 15:1 to 1:1, wherein the molar ratio Mo/(W and Nb) ranges from 80:1 to 1:4, wherein the precursor material is obtained by a process comprising preparing an intimate dry blend comprising ammonium ions from starting compounds, wherein the starting compounds comprise the elemental constituents of the multi-element oxide material other than the oxygen, wherein the gas in the gas stream comprises from 0.5% to 4% by volume of O from 1% to 8% by volume of NH and steam and/or inert gas in residual amounts, wherein the NH wherein at least a portion of the gas stream flowing through the rotary tube furnace is circulated, and wherein no additional amount of NH