JPH11255680A - Production of benzene nuclear chlorine-substituted compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound useful as a raw material for medicines, agrochemicals, etc., in high yield by chlorodenitrating a readily available nitrotoluene. SOLUTION: (A) A nitrotoluene compound represented by formula I [X is a halogen; (m) is an integer of 0-3; (n) is 1 or 2, with the proviso that both the 2- and the 6-positions are not substituted with halogens or nitro] is reacted with (B) chlorine gas to thereby afford (C) a compound represented by formula II (R is trichloromethyl or chlorocarbonyl, with the proviso that both the 2- and the 6-positions are not substituted with halogens). Furthermore, the chlorinating reaction is preferably carried out at 100-300 deg.C reactional temperature by using the component B in an amount of >=2 mol (more preferably 2-10 mol) based on 1 mol component A. Thereby, the trichloromethylbenzene compound and the benzoyl chloride compound can be produced at the same time in high yield. The two compounds are readily separated and purified by distilling operations, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a benzene nucleus chlorine-substituted compound useful as a raw material for medicines, agricultural chemicals, and the like. More specifically, the present invention relates to a method for producing a benzene nucleus using a nitrotoluene compound. The present invention relates to a method for producing a chlorine-substituted trichloromethylbenzene compound and a benzoyl chloride compound in high yield.

[0002]

2. Description of the Related Art Conventionally, trichloromethylbenzenes substituted with nuclei of chlorine have been produced by chlorinating the methyl group of the corresponding chloronuclear compounds of toluene. The chlorinated benzoyl chloride compound is produced by hydrolyzing the trichloromethylbenzene. The chloro-substituted compound of toluene used as a raw material in this method can be obtained as a mixture of isomers by nuclear chlorination of toluene, but is usually a liquid at ordinary temperature. Separation and purification operations are required. However, since the difference between the vapor pressures of the isomers is small, a rectification column requiring a high number of distillation stages is required for separation by distillation, and an expensive adsorbent such as zeolite is required for separation by adsorption. Must be used. For this reason, there has been a demand for the development of a method capable of producing a trichloromethylbenzene nucleus chlorine-substituted compound at low cost using a compound that is industrially easily available as a raw material instead of a toluene-nuclear chlorine substitution compound.

[0003]

Accordingly, the present invention provides
It is an object of the present invention to provide a method capable of producing a nuclear chlorine-substituted trichloromethylbenzene compound and a nuclear chlorine-substituted benzoyl chloride compound at a high yield using a compound that is industrially easily available as a raw material.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned problems. As a result, since nitrotoluene is usually a solid at ordinary temperature, it can be separated and purified by recrystallization or the like, and nitrotoluene which is relatively easily available can be removed. It has been found that nitrochlorination enables trichloromethylbenzene and benzoyl chloride, whose benzene nuclei have been substituted with chlorine, to be obtained as the main products at the same time in high yield, and the present invention has been accomplished based on this finding. That is, the present invention provides a compound represented by the general formula (I):

[0005]

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(Wherein X represents a halogen atom, m represents an integer of 0 to 3, and n represents 1 or 2. However, both the 2-position and the 6-position are substituted with a halogen atom or a nitro group. Wherein a nitrotoluene compound represented by the general formula (II) is reacted with chlorine gas.

[0007]

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(Wherein R represents a trichloromethyl group or a chlorocarbonyl group, and X, m and n represent the general formula (I)
Is synonymous with However, neither the 2-position nor the 6-position is substituted with a halogen atom. ) Is provided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The nitrotoluene compound used in the present invention is represented by the above general formula (I). General formula (I)
X represents a halogen atom, for example, a chlorine atom,
Examples thereof include a bromine atom and an iodine atom, and a chlorine atom is preferable. m represents an integer of 0 to 3 and n represents 1 or 2, but neither the 2-position nor the 6-position is substituted with a halogen atom or a nitro group.

As the compound represented by the general formula (I),
Specifically, for example, m-nitrotoluene, p-nitrotoluene, o-nitrotoluene, 2-chloro-4-nitrotoluene, 2-chloro-3-nitrotoluene, 2-chloro-5-nitrotoluene, 4-chloro-2-nitrotoluene, 4-chloro-3-nitrotoluene, 3-chloro-
4-nitrotoluene, 3-chloro-2-nitrotoluene, 3-chloro-5-nitrotoluene, 5-chloro-2
-Nitrotoluene, 2,4-dichloro-5-nitrotoluene, 3,4-dichloro-2-nitrotoluene, 3,4
-Dichloro-5-nitrotoluene, 4,5-dichloro-
2-nitrotoluene, 2,5-dichloro-4-nitrotoluene, 2,5-dichloro-3-nitrotoluene, 3,
5-dichloro-2-nitrotoluene, 3,5-dichloro-4-nitrotoluene, 2,4,5-trichloro-3-
Nitrotoluene, 3,4,5-trichloro-2-nitrotoluene, 2,3,4-trichloro-5-nitrotoluene and the like can be mentioned.

The chlorination reaction of the compound of the above general formula (I) in the present invention is usually carried out at 100 to 300 ° C., preferably 1 to 300 ° C.
At a reaction temperature of 50 to 250 ° C., usually 2 mol or more, preferably 2 to 2 mol per mol of the compound represented by the general formula (I)
Performed using 10 moles of chlorine gas. The reaction time is not particularly limited, but is preferably 2 to 40 hours. The method of the present invention can be carried out without a solvent, but if necessary, a solvent that is stable under the reaction conditions of the method of the present invention can also be used.
Examples of such a solvent include 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, benzonitrile and the like. One kind may be used alone, or two or more kinds may be used in combination. Can also. When a solvent is used, it is preferably 100 ml or more, more preferably 200 to 200 mol per mol of the compound represented by the general formula (I).
Use 0 ml.

In the present invention, the compound represented by the general formula (I) is denitrochlorinated using chlorine gas in this way, whereby a trichloromethylbenzene compound and a benzoyl chloride compound are produced together to obtain a high yield. It can be obtained in yield. In the general formula (II), R represents a trichloromethyl group or a chlorocarbonyl group, and X, m and n have the same meanings as described for the general formula (I). In the general formula (II), both the 2-position and the 6-position are not substituted with a halogen atom. The trichloromethylbenzene compound and benzoyl chloride compound obtained by the method of the present invention, in which the benzene nucleus has been substituted with chlorine, can be easily separated and purified by a commonly used method such as a distillation operation.
Further, by hydrolyzing the obtained reaction product as it is, it can be easily isolated as the corresponding chlorinated benzoic acid.

Among the compounds represented by the general formula (II) obtained in the present invention, examples of the chloro-substituted trichloromethylbenzene compound include, for example, m-chlorobenzotrichloride, p-chlorobenzotrichloride and o-chlorobenzotrichloride. −
Chlorobenzotrichloride, 2,4-dichlorobenzotrichloride, 2,3-dichlorobenzotrichloride, 2,5-dichlorobenzotrichloride, 3,4-
Dichlorobenzotrichloride, 3,5-dichlorobenzotrichloride, 2,4,5-trichlorobenzotrichloride, 2,3,4-trichlorobenzotrichloride, 3,4,5-trichlorobenzotrichloride,
2,3,5-trichlorobenzotrichloride, 2,
3,4,5-tetrachlorobenzotrichloride and the like.

Among the compounds represented by the general formula (II), examples of the nuclear chlorine-substituted benzoyl chloride compound include, for example, m-chlorobenzoyl chloride, p-chlorobenzoyl chloride, o-chlorobenzoyl chloride, 2,4-dichlorobenzoyl chloride, 2,3-dichlorobenzoyl chloride, 2,5
-Dichlorobenzoyl chloride, 3,4-dichlorobenzoyl chloride, 3,5-dichlorobenzoyl chloride, 2,4,5-trichlorobenzoyl chloride, 2,3,4-trichlorobenzoyl chloride,
3,4,5-trichlorobenzoyl chloride, 2,
3,5-trichlorobenzoyl chloride, 2,3
4,5-tetrachlorobenzoyl chloride and the like.

[0015]

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. Example 1 137.1 g (1.0 mol) of m-nitrotoluene was added to a 300 ml four-necked reaction flask equipped with a stirrer, a thermometer, a Dimroth, and a chlorine blowing tube, and stirred while stirring.
The temperature was raised to 80 ° C. 177.3g of chlorine gas at the same temperature
(2.5 mol) was bubbled in over about 15 hours. The temperature was further raised to 200 ° C., and 106.4 g (1.5 mol) of chlorine gas was blown in over about 10 hours. When the obtained reaction solution was analyzed by gas chromatography, the composition (molar ratio) was m-chlorobenzoyl chloride 63.4%, m
-Chlorobenzotrichloride was 26.9% (a total of 90.3% of the trichloromethylbenzene compound and the benzoyl chloride compound). Nitrogen gas was blown into the reaction solution to remove excess chlorine gas out of the system, followed by distillation under reduced pressure.
-Chlorobenzoyl chloride (106.4 g, yield 6)
0.8%, purity 98.6%) and m-chlorobenzotrichloride 59.0 g (yield 26.0%, purity 98.6)
%).

Reference Example 1 Concentrated sulfuric acid was added to a reaction solution obtained in the same manner as in Example 1.
Then, 4.7 g of water was added dropwise at 140 ° C. over about 2 hours. After aging at the same temperature for 2 hours, 500 ml of o-chlorotoluene was added, and water was added again at 140 ° C.
1 g was added dropwise in about 3 hours. The reaction solution was cooled to 20 ° C., and the precipitated solid was filtered and dried at 60 ° C. overnight.
126.8 g (yield: 81.0%, purity: 99.9%) of -chlorobenzoic acid was obtained.

Example 2 In a 100 ml four-necked reaction flask equipped with a stirrer, thermometer, Dimroth and chlorine blowing tube, 2-chloro-4- was added.
17.2 g (0.1 mol) of nitrotoluene was added, and the temperature was raised to 180 ° C. while stirring. Chlorine gas 1 at the same temperature
7.7 g (0.25 mol) were blown in over about 15 hours. Then raise the temperature to 200 ° C and chlorine gas 10.6g
(0.15 mol) was blown in over about 10 hours. When the obtained reaction solution was analyzed by gas chromatography, the composition (molar ratio) was 2,9.4-dichlorobenzoyl chloride 79.4%, 2,4-dichlorobenzotrichloride 14.7% (trichloromethylbenzene compound and Benzoyl chloride compound in total 94.1%).

EXAMPLE 3 2-Chloro- instead of 2-chloro-4-nitrotoluene
A denitrochlorination reaction was carried out in exactly the same manner as in Example 2 except that 5-nitrotoluene was used. When the obtained reaction solution was analyzed by gas chromatography, the composition (molar ratio) was 2,5-dichlorobenzoyl chloride.
5%, 2,5-dichlorobenzotrichloride 28.3
% (Total 95.8% of the trichloromethylbenzene compound and the benzoyl chloride compound).

Example 4 4-Chloro- instead of 2-chloro-4-nitrotoluene
A denitrochlorination reaction was carried out in exactly the same manner as in Example 2 except that 3-nitrotoluene was used. When the obtained reaction solution was analyzed by gas chromatography, the composition (molar ratio) was 3,4-dichlorobenzoyl chloride.
1%, 3,4-dichlorobenzotrichloride 54.6
% (Total of 87.7% of the trichloromethylbenzene compound and the benzoyl chloride compound).

Example 5 13.7 g (0.10 mol) of m-nitrotoluene and 30 ml of 1,2,4-trichlorobenzene were placed in a 300 ml four-necked reaction flask equipped with a stirrer, thermometer, Dimroth and chlorine blowing tube. In addition, the temperature was raised to 180 ° C. while stirring. At the same temperature, 177.3 g of chlorine gas (2.5
Mol) over about 15 hours. 200 ° C
The temperature was raised to 106.4 g (1.5 mol) of chlorine gas for about 1
It took 0 hours. When the obtained reaction solution was analyzed by gas chromatography, the composition (molar ratio) was m-
46.6% of chlorobenzoyl chloride, 39.9% of m-chlorobenzotrichloride (total of 88.6% of trichloromethylbenzene compound and benzoyl chloride compound).
5%).

The remainder of the reaction solution obtained in Examples 1 to 5 other than the trichloromethylbenzene compound and the benzoyl chloride compound was a small amount of a reaction intermediate (one having a nitro group remaining, benzal chlorides) and It was a by-product such as benzoic acids and benzoic anhydride.

[0022]

According to the method of the present invention, a benzene nucleus chlorine-substituted compound can be produced in a high yield by a denitrochlorination reaction of an inexpensive nitrotoluene compound, so that the production cost can be greatly reduced. In the method of the present invention, a trichloromethylbenzene compound and a benzoyl chloride compound are simultaneously obtained as a main product in a one-step reaction,
A high-purity benzoyl chloride compound and a trichloromethylbenzene compound can be obtained only by separation and purification after the reaction without performing a hydrolysis reaction of the trichloromethylbenzene compound as in the related art.

Claims (1)

[Claims] 1. A compound of the general formula (I) (In the formula, X represents a halogen atom, m represents an integer of 0 to 3, and n represents 1 or 2. However, both the 2- and 6-positions are not substituted with a halogen atom or a nitro group. Wherein a nitrotoluene compound represented by the formula) is reacted with chlorine gas. (In the formula, R represents a trichloromethyl group or a chlorocarbonyl group, and X, m and n have the same meanings as in the general formula (I), provided that both the 2- and 6-positions are substituted with halogen atoms. The method for producing a benzene nucleus chlorine-substituted compound represented by the formula: