Patent ID: 6632965
Filing Date: 2003-10-14
Classification: B01J,C07C

Abstract:
A process for producing acrolein and acrylic acid by the vapor-phase catalytic oxidation of propylene with molecular oxygen or a molecular oxygen-containing gas in a fixed-bed multitubular reactor, which comprises(a) using, as the catalysts therefor, compound oxide catalysts of the formula Mo12WbBicFedAeBfCgDhOxâ€ƒâ€ƒ(I) wherein Mo is molybdenum; W is tungsten, Bi is bismuth; Fe is iron; A is at least one element selected from the group consisting of cobalt and nickel; B is at least one element selected from the group consisting of phosphorus, antimony, boron, tin, cerium, niobium, lead, chromium and zinc; C is at least one element selected from the group consisting of alkali metals and thallium; D is at least one element selected from the group consisting of silicon, aluminum, titanium and zirconium; O is oxygen; b, c, d, e, f, g, h and x are the number of atoms of W, Bi, Fe, A, B, C, D and O, respectively; and b has a value of 0 to 5, c has a value of 0.1 to 10, d has a value of 0.1 to 10, e has a value of 1 to 20, f has a value of 0 to 5, g has a value of 0.001 to 3, h has a value of 0 to 30, and x has a value determined by the oxidation state of each element, and(b) packing said catalysts in each reaction tube having two or more reaction zones disposed along the axis of the tube in such a way that the catalyst packed in the reaction zone on the gas outlet side has a lower ratio of the Bi and Fe content to the Mo content than the catalyst packed in the reaction zone on the gas inlet side.