| 摘要 |
<p>A process for producing methacrolein and methacrylic acid by the vapor phase catalytic oxidation of at least one of isobutylene, t-butanol and methyl t-butyl ether with molecular oxygen or a gas containing the same in a fixed bed multitubular reactor, characterized in that: α the catalyst used herein is a composite oxide of general formula (I) MoaWbBicFedAeBfCgDhEiOx; wherein Mo represents molybdenum; W represents tungsten; Bi represents bismuth; Fe represents iron; A represents at least one element selected between nickel and cobalt; B represents at least one element selected from among alkali metals and thallium; C represents at least one element selected from among alkaline earth metals; D represents at least one element selected from among phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic and zinc; E represents at least one element selected from among silicon, aluminium, titanium and zirconium; O represents oxygen; a, b, c, d, e, f, g, h, i, and x are the numbers of atoms represented by Mo, W, Bi, Fe, A, B, C, D, E and O, respectively; and b is 0-10, c is 0.1-10, d is 0.1-20, e is 2-20, f is 0-10, g is 0-10, h is 0-4, i is 0-30, and x is a value dependent on the oxidation state of each element, when a is 12, β a plurality of reaction zones are provided by dividing a catalyst layer into at least two layers in the axial direction of each reaction tube, and η catalysts with different activities prepared by varying the kinds and/or amounts of the elements of groups A, B, C, D and E in general formula (I) of the item α, and/or catalysts with different activities prepared by varying the amount of at least one element selected from among W, Bi and Fe are packed in said plurality of reaction zones in such a manner that the catalytic activity increases along a path from the feed port of starting gas to the discharge port.</p> |
