Process for preparing catalysts for producing methacrylic acid

• Main Authors: ISHII, KAZUHIRO, OH-KITA, MOTOMU, KURODA, TORU
• Format: Patent
• Language: English; French; German
• Published: 02.05.1991
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; APPARATUS THEREFOR; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; GENERAL METHODS OF ORGANIC CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING

In a process for producing a catalyst having a composition represented by the following formula usable to produce methacrylic acid by the gas-phase catalytic oxidation of methacrolein with molecular oxygen, PaMobCucVdXeYfZgOh wherein P, Mo, Cu, V and O are phosphorus, molybdenum, copper, vanadium and oxygen, respectively, X is at least one element selected from the group consisting of arsenic, antimony, bismuth, germanium, zirconium, tellurium and silver, Y is at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, manganese, barium, boron, gallium, cerium and lanthanum, Z is at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, a, b, c, d, e, f, g and h are an atomic ratio of each element, and when b is 12, a is 0.5 to 3, c is 0.01 to 2, d is 0.01 to 3, e is 0.01 to 3, f is 0 to 3, g is 0.01 to 2 and h is the number of oxygen atoms necessary to satisfy the valence of each component, an improvement comprising adding 0.05 to 1.0 mole of nitric acid based on 12 moles of a molybdenum atom to a slurry containing materials for the catalyst components. According to the present invention, a catalyst for gas-phase catalytic oxidation excellent in the conversion of methacrolein and selectivity for methacrylic acid is obtained.