Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1987-08-21
1989-02-07
Garner, Vivian
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
502206, 502209, C07C 5125, C07C 57055
Patent
active
048033022
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a process for the production of methacrylic acid by vapor phase catalytic oxidation of methacrolein and a catalyst to be used for the process.
BACKGROUND ART
There have hitherto been disclosed in patents enormous methods with reference to processes for producing unsaturated carboxylic acids by vapor phase catalytic oxidation of unsaturated aldehydes, for example, a process for the production of methacrylic acid by vapor phase catalytic oxidation of methacrolein. These patents put emphasis on the method of producing acrylic acid from acrolein, and the method was impractical because of a low rate of selectivity due to severe side reaction and short life of the catalysts disclosed in the patents on using the catalysts as the ones for producing methacrylic acid.
On the other hand, many catalysts have been proposed for producing methacrylic acid from methacrolein. But these catalysts have problems that they are insufficient in reactivity, catalyst activity decreases greatly with the passage of time or high temperature is required for the reaction, so that a further improvement for the use as an industrial catalyst is required.
DISCLOSURE OF THE INVENTION
The object of this invention is to provide a process for producing advantageously methacrylic acid from methacrolein. In particular, the object of this invention is to provide a catalyst which is excellent in activity, selectivity and life and thus has high practicability for producing methacrylic acid and a process for producing methacrylic acid by using said catalyst.
BEST MODE FOR PRACTICING THE INVENTION
This invention relates to a catalyst practicable for producing methacrylic acid by the vapor phase oxidation of methacrolein with molecular oxygen, which is represented by the general formula group consisting of potassium, rubidium, cesium and thallium, Y represents at least one or more of the elements selected from the group consisting of tellurium, lanthanum, boron, silver, chromium, magnesium and barium, Z represents any one of the elements of zirconium or antimony, a to i denote atomic ratios of respective elements, and when b=12, a=0.3-4, c=0.01-3, d=0.01-4, e=0.01-3, f=0.1-3, g=0.1-3, h=0.001-5 and i denotes the number of oxygen required for satisfying the valence number of the aforementioned ingredients, and a process for producing methacrylic acid characterized by using said catalyst.
The catalyst of this invention has a basic composition of phosphorus, molybdenum, vanadium and copper, and comprises additionally at least one or more of the elements selected from the group consisting of a specific amount of iron and zirconium or antimony and potassium, rubidium, cesium and thallium, and at least one or more of specific elements selected from the group consisting of tellurium, lanthanum, boron, silver, chromium, magnesium and barium. The catalyst may be used industrially very advantageously and thus the catalyst activity can be maintained at a high level over a long period of time, because the catalyst is high in activity and selectivity for producing methacrylic acid from methacrolein and it can provide a sufficient rate of reaction even at low reaction temperature owing to its high activity. The atomic ratios of respective elements may be any one of the aforementioned ratios and may be suitably selected from the aforementioned ranges of the ratios. The ratios are preferably in the ranges 1-2.5 for a, 0.05-1.5 for c, 0.5-2 for d, 0.05-2 for e, 0.1-1.5 for f, 0.1-2 for g and 0.01-2 for h when b is 12.
As the process for preparing the catalyst of this invention, a variety of methods such as evaporation to dryness, precipitation and the like may be used provided that the components will not distribute unevenly departing from the aforementioned atomic ranges.
As the raw materials used for preparing the catalyst, there may be used nitrates, carbonates, ammonium salts, halides, oxides or the like of respective elements in combinations thereof.
The catalyst of this invention may be used as a bare catalyst
REFERENCES:
patent: 4320227 (1982-03-01), Matsumoto et al.
patent: 4341900 (1982-07-01), Ishii et al.
patent: 4558029 (1985-12-01), Paparizos et al.
Kato Masaaki
Kobayashi Masao
Oh-Kita Motomu
Garner Vivian
Mitsubishi Rayon Co. Ltd.
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