Patent ID: 6541664
Filing Date: 2003-04-01
Classification: B01J,C07C

Abstract:
A process for the heterogeneously catalyzed gas-phase oxidation of propane to acrolein and/or acrylic acid, in which a reaction gas starting mixture comprising propane, molecular oxygen and, if desired, inert gas is passed at from 300 to 500Â° C. over a fixed-bed catalyst which comprises two catalyst beds A and B arranged spatially in succession, with the proviso that the active composition of bed A is at least one multimetal oxide of the formula IMa1Mo1âˆ’bMb2Oxâ€ƒâ€ƒ(I), where M1=Co, Ni, Mg, Zn, Mn and/or Cu,M2=W, V, Te, Nb, P, Cr, Fe, Sb, Ce, Sn and/or La, a=0.5-1.5, b=0-0.5 x=a number which is determined by the valence and amount of the elements different from oxygen in I, and the active composition of bed B is at least one multimetal oxide of the formula IIBia, Mob, X1c, X2d, X3e, X4f, X5g, X6h, Ox,â€ƒâ€ƒ(II), where X1=W, V and/or Te,X2=alkaline earth metal, Co, Ni, Zn, Mn, Cu, Cd, Sn and/or Hg, X3=Fe, Cr and/or Ce, X4=P, As, Sb and/or B, X5=alkali metal, Tl and/or Sn, X6=rare earth metal, Ti, Zr, Nb, Ta, Re, Ru, Rh, Ag, Au, Al, Ga, In, Si, Ge, Th and/or U, aâ€²=0.01-8, bâ€²=0.1-30, câ€²=0-20, dâ€²=0-20, eâ€²=0-20, fâ€²=0-6, gâ€²=0-4, hâ€²=0-15, xâ€²=a number which is determined by the valence and amount of the elements different from oxygen in II, wherein the reaction gas starting mixture comprises &gE;50% by volume of propane, &gE;15% by volume of O2 and from 0 to 35% by volume of inert gas and flows through the catalyst beds A and B in the order first A, then B.