Patent ID: 6476259
Filing Date: 2002-11-05
Classification: B01J,C07C

Abstract:
A process for producing methacrylic acid through vapor phase catalytic oxidation, or vapor phase catalytic oxidation and catalytic oxidative dehydrogenation, or catalytic oxidative dehydrogenation of at least one compound selected from the group consisting of methacrolein, isobutylaldehyde and isobutyric acid with molecular oxygen or a molecular oxygen containing gas, the process being characterized in that it uses a catalyst characterized in that it is a complex oxide composition comprising(A) a complex oxide containing as essential components molybdenum and phosphorus, which is known per se as catalyst for said vapor phase catalytic oxidation and/or vapor phase oxidative dehydrogenation reaction expressed by the following general formula (1): PaMobAcBdCeDfEgOxâ€ƒâ€ƒ(1) wherein P is phosphorus; Mo is molybdenum; A is at least one element selected from the group consisting of arsenic, antimony, germanium, bismuth and selenium; B is at least one element selected from the group consisting of copper, silver, iron, cobalt, nickel, lead, manganese, chromium, tin, zinc, palladium, rhodium and tellurium; C is at least one element selected from the group consisting of tungsten, vanadium and niobium; D is at least one element selected from the group consisting of alkali metals and alkaline earth metals; E is at least one element selected from the group consisting of titanium, silicon and aluminum; and O is oxygen; a,b,c,d,e,f g and x denote the atomic ratios of P, Mo, A, B, C, D, E and O respectively; and where b is 12, a is 0.5-4, c is 0.01-3, d is 0.01-5, e is 0.01-5, f is 0.01-6 and g is 0.01-10; and x is determined by the degree of oxidation of each of the elements and(B) a complex oxide containing cerium and zirconium as the essential components.