Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1987-01-12
1992-08-04
Dees, Jose G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568432, 562415, C07C 4536, C07C 51255
Patent
active
051361043
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a method for the production of a substituted benzaldehyde. More particularly, this invention relates to a method for the production in a high yield of a substituted benzaldehyde by the catalytic gas-phase oxidation of a substituted toluene. Yet more particularly, this invention relates to a method for the production in a high yield of a substituted benzaldehyde represented by the general formula II: ##STR1## wherein R stands for methoxy group, tertiary butyl group, or phenoxy group and n for an integer of the value of 1 to 3, by the catalytic gas-phase oxidation of a substituted toluene represented by the general formula I: ##STR2## wherein R and n have the same meanings as defined above, with a molecular oxygen-containing gas.
2. Background Art
Heretofore, as means of synthesizing benzaldehydes by the partial oxidation of toluenes, the methods resorting to liquid-phase oxidation or electrolytic oxidation have been known to the art (as disclosed in the specification of Japanese Patent Publication SHO 55(1980)-42,974, Japanese Patent Laid-open SHO 54(1979)-109,937, Japanese Patent Laid-open SHO 55(1980)-85,682, and Japanese Patent Laid-open SHO 56(1981)-127,327). Then, as means of producing tertiary butyl or pheoxy-substituted benzaldehyde, the methods resorting to liquid-phase oxidation, electrolytic oxidation, or halogenation-hydrolysis of a compound represented by the aforementioned general formula (I) with a reagent have been known (as disclosed in the specification of Japanese Patent Laid-open SHO 52(1977)-125,137; Journal of Synthetic Organic Chemistry, Japan. Vol. 37, No. 8, p 667; and Journal of The National Chemical Laboratory for Industry Vol. 78, No. 2, p 19). When these methods are to be put to work commercially, however, they entail various problems such as inevitable requirement for a step of waste water disposal, excessively heavy consumption of electricity, and excessive complication of procedure. Thus, they cannot be called economically advantageous.
For the solution of these problems, therefore, a method of production resorting to commercially advantageous gas-phase oxidation is expected. Besides the methods mentioned above, methods for producing benzaldehydes by catalytic gas-phase oxidation of such methylbenzens as toluene, xylene, pseudocumene, and durene have been known to the art (as disclosed in West German Patent No. 1,947,994, U.S. Pat. No. 4,137,259, and Japanese Patent Publication SHO 51(1976)-33,101). These methods carry out their respective reactions by using vanadium type and tungsten-molybdenum type catalysts. The yields of these reactions are invariably low.
As regards the gas-phase oxidation of methoxy-substituted toluene, for example, a molybdenum-bismuth-iron-nickel type catalyst is disclosed (in the specification of West German Patent No. 2,841,712). This catalyst has no economic value because the yield of the oxidation is extremely low.
In the specification of Japanese Patent Publication SHO 58(1983)-4,012, a catalyst composed of vanadium, phosphorus, potassium sulfate, and copper is proposed for the production of anisaldehyde (p-methoxy benzaldehyde) by the oxidation of p-methoxy toluene and this catalyst is reported to have produced anisaldehyde in an one-pass yield of 65.0 mol %. In this case, however, the conversion of p-methoxy toluene is as low as 71.5 mol %, although the reaction temperature is as high as 495.degree. C. Since this catalyst contains a large proportion of potassium sulfate which is held to be thermally instable, it has room for doubt about catalyst life. In view of the high price of p-methoxy toluene as the starting material, the fact that the conversion thereof is low renders the oxidation disadvantageous as a commercial means of production.
The methoxy-substituted benzaldehyde is expected to be a product of high purity especially when it is meant as a raw material for medicines and pesticides. When the catalysts disclosed in the aforementioned publications are used in the production of thi
REFERENCES:
patent: 4054607 (1977-10-01), Matsuoka
patent: 4137259 (1979-01-01), Van Geem et al.
Nagai Isao
Nakamura Isao
Saito Noboru
Takatsu Kazuhiro
Ueshima Michio
Behr Omri M.
Dees Jos,e G.
Nazario Porfirio
Nippon Shokubai Kagaku Kogyo & Co., Ltd.
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