Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2002-09-06
2004-04-13
Kumar, Shailendra (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C558S411000, C558S425000
Reexamination Certificate
active
06720458
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a catalyst useful for a photooxidation reaction and also relates to a novel process for producing aldehydes, particularly aromatic aldehydes, which are useful as an intermediate for the production of agrochemical and medical preparations. The catalyst is particularly suitable for the oxidation of a methyl group difficult to oxidize.
BACKGROUND ART
The production method of aldehydes is generally not easy and various methods are being studied, such as oxidation of methyl group, reduction of carboxylic acid and reductive hydrolysis of nitrile. Particularly, according to the method of oxidizing a methyl group, the oxidation reaction terminates at the stage of an alcohol or continues until the production of a carboxylic acid in many cases and it is difficult to stop the reaction at the stage of an aldehyde by a general oxidation method.
The production process for aldehydes is described by referring to the case of producing cyanobenzaldehydes. Several methods for the production of cyanobenzaldehydes are known.
For example, J. Am. Chem. Soc., 75, 1125 (1953) discloses a method of reducing cyanobenzoyl chloride by the Rosenmund reduction. JP-A-60-166655 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses a method of reacting p-cyanobenzyl chloride with hexamethylenetetramine in an oil-water two-layer system. JP-A-9-227490 discloses a method of reacting dichloromethylbenzonitrile with morpholine and then hydrolyzing the reactant.
These methods all involve generation of a large amount of wastes and cannot be an industrially excellent production process.
A photooxidation reaction using a catalyst is a conventionally known method. For example, as for the method of converting a toluene into an aromatic aldehyde by a photooxidation reaction, Org. Lett. 2000, 2, 3647 discloses a method of oxidizing p-xylene with an oxygen using 9-phenyl-10-methylacridinium as a photocatalyst to produce p-tolualdehyde. However, this catalyst is not inexpensive and not easily available.
One object of the present invention is to provide a catalyst useful for a photooxidation reaction. Another object of the present invention is to provide means for producing aromatic aldehydes which are useful as an intermediate in the production of agrochemical and medical preparations, by an industrially advantageous method.
SUMMARY OF THE INVENTION
The present invention relates to the following matters.
[1] A photooxidation catalyst which is a halogenated aromatic nitrile represented by the following formula (1):
(wherein X represents a chlorine atom or a fluorine atom, m represents an integer of 1 to 5, n represents an integer of 1 to 5, m+n≦6, and when n is 2 or more, Xs may be the same or different).
[2] The photooxidation catalyst as described in [1], wherein the halogenated aromatic nitrile is at least one selected from the group consisting of tetrafluoroterephthalonitrile, tetrafluoroisophthalonitrile and tetrafluorophthalonitrile.
[3] The photooxidation catalyst as described in [2], wherein the halogenated aromatic nitrile is tetrafluoroterephthalonitrile.
[4] The photooxidation catalyst as described in any one of [1] to [3], wherein the catalyst is used for photooxidation reaction of converting a methyl group into an aldehyde group.
[5] The photooxidation catalyst as described in any one of [1] to [3], wherein the catalyst is used for photooxidation reaction of converting a methyl group of methyl group-substituted aromatics into an aldehyde group.
[6] The photooxidation catalyst as described in any one of [1] to [3], wherein the catalyst is used for photooxidation reaction of converting a methyl group of methylbenzene derivatives into an aldehyde group.
[7] The photooxidation catalyst as described in any one of [1] to [3], wherein the catalyst is used for photooxidation reaction of converting a methylbenzene represented by formula (2):
(wherein Y represents a chlorine atom, a fluorine atom, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, an alkyl group having from 1 to 4 carbon atoms which may have a substituent, an alkoxy group having from 1 to 4 carbon atoms which may have a substituent, or an aldehyde group, p represents an integer of 0 to 5, and when p is 2 or more, Ys may be the same or different) to a benzaldehyde represented by formula (3):
(wherein Y represents a chlorine atom, a fluorine atom, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, a sulfonic acid group, an alkyl group having from 1 to 4 carbon atoms which may have a substituent, an alkoxy group having from 1 to 4 carbon atoms which may have a substituent, or an aldehyde, p represents an integer of 0 to 5, when p is 2 or more, Ys may be the same or different).
[8] A process for producing aldehydes, comprising photooxydizing a methyl group into an aldehyde group in the presence of the photooxidation catalyst as described in any one of [1] to [3].
[9] The process for producing aldehydes as described in [8], wherein the methyl group is a methyl group of methyl group-substituted aromatics, and thereby producing an aromatic aldehyde.
[10] The process for producing aldehydes as described in [9], wherein the methyl group of methyl group-substituted aromatics is a methyl group of methylbenzene, and thereby producing a benzaldehyde.
[11] The process for producing aldehydes as described in [10], wherein the methylbenzene is represented by formula (2):
(wherein Y represents a chlorine atom, a fluorine atom, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, an alkyl group having from 1 to 4 carbon atoms which may have a substituent, an alkoxy group having from 1 to 4 carbon atoms which may have a substituent, or an aldehyde group, p represents an integer of 0 to 5, and when p is 2 or more, Ys may be the same or different), and by photooxydizing the methyl group of said methylbenzene, thereby producing a benzaldehyde represented by formula (3):
(wherein Y represents a chlorine atom, a fluorine atom, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, a sulfonic acid group, an alkyl group having from 1 to 4 carbon atoms, which may have a substituent, an alkoxy group having from 1 to 4 carbon atoms, which may have a substituent, or an aldehyde, p represents an integer of 0 to 5, when p is 2 or more, Ys may be the same or different).
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is described in detail below. Halogenated aromatic nitrites as the catalyst for use in the present invention are put on the market and easily available. In formula (1), the nitrile group and the halogen are not limited on the number of bonds and the position of bonding. Examples of the halogen include chlorine and fluorine.
Specific examples of the halogenated aromatic nitrites represented by formula (1) include tetrafluorophthalonitile, tetrafluoroisophthalonitrile, tetrafluoroterephthalonitrile, pentafluorobenzonitrile, 2,3,5,6-tetrafluorobenzonitrile, 2,3,4,6-tetrafluorobenzonitrile, 2,3,4,5-tetrafluorobenzonitrile, 2,4,6-trifluoro-5-chloroisophthalonitrile, tetrachlorophthalonitrile, tetrachloroisophthalonitrile and tetrachloroterephthalonitrile. Among these, preferred are tetrafluorophthalonitrile, tetrafluoroisophthalonitrile and tetrafluoroterephthalonitrile, more preferred is tetrafluoroterephthalonitrile.
These halogenated aromatic nitrites may be used individually or in combination of two or more thereof.
The photooxidation reaction is performed by applying light in the presence of an oxygen and a photooxidation catalyst. If the oxidizing power of the photooxidation catalyst is low, the oxidation reaction does not proceed, whereas if it is excessively high, a side reaction takes place and the selectivity decreases.
The light a
Fukuzumi Shunichi
Morikawa Kohei
Ohkubo Kei
Ohnishi Yutaka
Kumar Shailendra
Showa Denko K.K.
Witherspoon Sikarl A.
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