JP2002154995A - Method for producing chlorinated aromatic compounds - Google Patents

Abstract

(57) Abstract: In an chlorination reaction of an aromatic compound, an o-chloroaromatic compound, a p-chloroaromatic compound, a 2,6-dichloroaromatic compound, or a 2,5-dichloroaromatic compound is used. Obtain compounds with high selectivity. In an chlorination reaction of an aromatic compound in the presence of a Lewis acid catalyst, an o-chloroaromatic compound or 2,2 is obtained.
When selectively obtaining the 6-dichloro aromatic compound, the total amount of water in the raw material liquid and the chlorinating agent with respect to the Lewis acid catalyst is less than 1.0 in molar ratio, and further, the p-chloro aromatic compound, Alternatively, when the 2,5-dichloroaromatic compound is selectively obtained, the total amount of water in the raw material liquid and the chlorinating agent with respect to the Lewis acid catalyst is set to 1.0 in a molar ratio.
This is performed as described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a chlorinated aromatic compound which is useful as a raw material for various organic synthetic chemicals such as pharmaceuticals, agricultural chemicals, and polymer raw materials.

[0002]

2. Description of the Related Art Regarding a method for producing a chlorinated aromatic compound by performing a chlorination reaction of an aromatic compound in the presence of a Lewis acid catalyst such as ferric chloride, antimony chloride, and aluminum chloride, reference is made to literatures. It is widely known in patents and the like. For example, in the chlorination of toluene in the presence of a ferric chloride catalyst, mainly o-chlorotoluene and p-chlorotoluene are produced in a ratio of about 65:35,
In the chlorination of chlorotoluene in the presence of a ferric chloride catalyst, 2,3-dichlorotoluene, 2,4-dichlorotoluene, 2,5-dichlorotoluene, and 2,6-dichlorotoluene each account for about 15%. %, 19%, 35%, 31%
Is generated with a selectivity of

On the other hand, various attempts have been made to change these composition ratios in response to a request from the market. For example, in the chlorination of toluene, a technique of performing chlorination using an iron sulfide catalyst in order to enhance the selectivity of the p-form (Japanese Patent Application Laid-Open No. 50-642)
No. 31), chlorination technology using an iron-selenium catalyst (Japanese Patent Publication No. 50-34009), aluminum trihalide and at least one halide selected from metals belonging to the group IA, silver, barium and ammonium. Chlorination technology using a double salt of as a catalyst (JP-A-56-99429), an organic sulfur compound having divalent sulfur as a co-catalyst in a Lewis acid (US Pat. No. 3,264,447), diphenyl selenide or aluminum selenide ( US4013
730), thianthrene compounds (Japanese Patent Publication No. 60-2)
No. 6772, Japanese Patent Publication No. 60-29364, Japanese Patent Publication No. 60-30299, US Pat. No. 4,024,198), a ferrocene derivative and a sulfur compound (US 403).
No. 1144), dithioxanthyl derivatives (Japanese Unexamined Patent Publication No.
8-222039), phenoxatin compounds (JP-B-62-42655, JP-B-62-42656).
JP-B-64-9297, phenothiazine compounds (JP-B-4-25065, JP-A-60-90).
125251), 1,3,7,9-tetrachloro-2,8-dimethylphenoxatin (JP-A-61-65).
No. 832), thiazepine compounds (JP-B 6-536).
No. 90, Japanese Patent No. 2604864, Japanese Patent No. 2853
352), 1,6-benzothiazosin compounds (JP-A-1-313443), benzo-1,4-thioxepan-5-one compounds and analogs thereof (US56).
A chlorination technique using a compound such as that disclosed in Japanese Patent No. 21153) is known.

As an effect of increasing the selectivity of the o-isomer, alcohol compounds (JP-A-5-255150) and polyether compounds (JP-A-7-33696) can be used as co-catalysts for Lewis acids. Are known.

[0005] Further, chlorination for producing dichlorotoluene is also carried out by using a metal sulfide having Lewis acidity or a Lewis acid in the presence of a sulfur compound as a catalyst to obtain dichlorotoluene from toluene or o-chlorotoluene. , 5
-Dichlorotoluene (US Pat. No. 4,031,146, JP-A-51-143627) and a technique for selectively obtaining 3,4-dichlorotoluene from p-chlorotoluene under the same catalyst conditions (US Pat. No. 4,403,145), and a technique for selectively obtaining 2,4-dichlorotoluene from p-chlorotoluene using zirconium chloride (US Pat. No. 3,366,698) or antimony chloride (US Pat. No. 4,0061,195) as a catalyst. Are known, but not many.

[0006]

However, most of these techniques are aimed at improving the selectivity of the chlorination reaction to the p-position of toluene, and have been studied from various aspects. As the effect is sought, the structure of the compound to be added as a co-catalyst becomes complicated and it becomes difficult to easily obtain it, which is disadvantageous when industrialization is considered. On the other hand, o-position-selective chlorination of toluene has little existing technology itself because there has never been a request from the market, but among them alcohols and polyether compounds known as cocatalysts, Since the compound is unstable under the reaction conditions in which hydrogen chloride is by-produced, a problem remains when separation and purification and recycle use of the catalyst are considered. Further, regarding the technology for obtaining dichlorotoluene,
Only a few techniques for obtaining 2,4-dichlorotoluene, 2,5-dichlorotoluene, 3,4-dichlorotoluene and the like are known, and none of them has a selectivity suitable for practical use. That is, in the prior art, it has been extremely difficult to realize a chlorination reaction in which the chlorine reaction position is controlled to meet the demand from the market.

[0007]

The present inventors have made intensive studies to solve these problems, and as a result, in the chlorination reaction of an aromatic compound in the presence of a Lewis acid,
Surprisingly, by controlling the total amount of water in the feed solution and chlorinating agent for the Lewis acid, the chlorine reaction position can be controlled, that is, the total amount of water in the feed solution and the chlorinating agent for the Lewis acid can be controlled by mole By making the ratio less than 1.0, o-chloro aromatic compound, or
The chlorination reaction can be carried out in such a form that the 2,6-dichloroaromatic compound can be selectively obtained, and the total amount thereof is 1.
By making it 0 or more, they have found that a chlorination reaction can be carried out in a form in which a p-chloroaromatic compound or a 2,5-dichloroaromatic compound can be selectively obtained, and have completed the present invention.

That is, the present invention provides the following formula (I)

[0009]

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Wherein R represents a lower alkyl group having 1 to 4 carbon atoms, wherein an aromatic hydrocarbon represented by the following formula (II) is chlorinated in the presence of a Lewis acid catalyst.

[0011]

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In the method for producing a chlorinated aromatic compound represented by the formula (1), the total amount of water in the raw material solution and the chlorinating agent with respect to the Lewis acid is less than 1.0 in molar ratio, and A method for producing a controlled chlorinated aromatic compound.

Further, the present invention provides a method of chlorinating a chlorinated aromatic compound represented by the above formula (II) in the presence of a Lewis acid catalyst,

[0014]

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In the method for producing a chlorinated aromatic compound represented by the formula (1), the total amount of water in the raw material liquid and the chlorinating agent with respect to the Lewis acid catalyst is less than 1.0 in molar ratio, A method for producing a group III compound.

Further, the present invention provides a method for producing a chlorinated aromatic compound represented by the above formula (III) by chlorinating an aromatic hydrocarbon represented by the above formula (I) in the presence of a Lewis acid catalyst. A method for producing a chlorinated aromatic compound, wherein the molar ratio of water in the raw material liquid and the chlorinating agent to the Lewis acid catalyst is less than 1.0.

Further, according to the present invention, an aromatic hydrocarbon represented by the above formula (I) is chlorinated in the presence of a Lewis acid catalyst, and the following formula (IV)

[0018]

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In the method for producing a chlorinated aromatic compound represented by the formula (1), the total amount of water in the raw material solution and the chlorinating agent with respect to the Lewis acid catalyst is adjusted to 1.0 or more in a molar ratio. A method for producing a group III compound.

Further, the present invention provides a method of chlorinating an aromatic hydrocarbon represented by the above formula (I) in the presence of a Lewis acid catalyst to obtain the following formula (V)

[0021]

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In the method for producing a chlorinated aromatic compound represented by the formula (1), the total amount of water in the raw material solution and the chlorinating agent with respect to the Lewis acid catalyst is adjusted to 1.0 or more by mole ratio. A method for producing a group III compound.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. In the present invention, the aromatic hydrocarbon used as a raw material is a compound represented by the following formula (I) (wherein, R represents a lower alkyl group having 1 to 4 carbon atoms);

[0024]

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Specifically, toluene, ethylbenzene,
Examples thereof include propylbenzene and butylbenzene, and preferably include toluene.

In the present invention, the chlorinated aromatic compound used as a raw material is a compound represented by the following formula (II) (wherein R represents a lower alkyl group having 1 to 4 carbon atoms). ,

[0027]

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Specifically, o-chlorotoluene, o-chloroethylbenzene, o-chloropropylbenzene, o-chlorotoluene,
-Chlorobutylbenzene, preferably o-
Chlorotoluene may be mentioned.

In the chlorination reaction of the present invention, various chlorinating agents such as chlorine, sulfuryl chloride and t-butyl hypochloride can be used, but usually chlorine alone is used. At that time, the chlorine may be added as it is, or may be diluted with an inert gas such as nitrogen. The amount of water contained in chlorine is generally several pp.
Although it is m to 10 to several ppm, there is no problem even if it is added as it is, and if necessary, it may be added after dehydration treatment with a dehydrating agent or the like.

In the present invention, the Lewis acid used as a catalyst includes, in addition to those generally known, those which form a Lewis acid during the chlorination reaction or exhibit a function thereof. Usually, elements such as antimony, iron, aluminum, gallium, boron, tin, titanium, zirconium, tungsten, zinc, niobium, bismuth, and tantalum, or halides, oxyhalides, oxides, sulfides, carbonyl compounds, and organic metals And the like. Typical examples thereof include ferric chloride, iron sulfide, aluminum chloride, antimony trichloride, antimony pentachloride, antimony oxychloride, titanium tetrachloride, tin tetrachloride, zirconium tetrachloride, tungsten hexachloride, zinc chloride, Examples thereof include niobium pentachloride, bismuth trichloride, and gallium trichloride, with preference given to aluminum chloride.

In the present invention, the desired o-chloroaromatic compound or 2,6-dichloroaromatic compound can be selectively obtained by controlling the water content with respect to the Lewis acid to a molar ratio of less than 1.0. A chlorination reaction can be performed. Preferably, it is kept below 0.7, more preferably below 0.3. At that time, the method of removing water from the raw material,
A commonly used method such as a distillation purification method or a method using a dehydrating agent such as molecular sieve or metallic sodium may be used. The amount of the Lewis acid used at that time is effective even if it is small, but it is 0.001 to 10% by weight, preferably 0.1 to 5.0% by weight, more preferably 0.3 to 10% by weight based on the raw material. 3.0% by weight.

In the present invention, the desired p-chloroaromatic compound or 2,5-dichloroaromatic compound can be selectively obtained by adjusting the water content to the Lewis acid to a molar ratio of 1.0 or more. A chlorination reaction can be performed. The amount of the Lewis acid used at that time is 0.001 to 10% by weight, preferably 0.005 to 5.0% by weight, and more preferably 0.01 to 3.0% by weight, based on the raw material.

In the present invention, the reaction temperature is usually from 0 to
It is 250 degreeC, Preferably it is 0-100 degreeC, More preferably, it is 0-50 degreeC. The reaction pressure may be any of normal pressure, increased pressure, and reduced pressure. The reaction may be performed in a gas phase or a liquid phase, but is usually performed in a liquid phase. The reaction may be carried out without using a solvent, or may be carried out using a solvent inert to the chlorination reaction. Specific examples of the solvent inert to the chlorination reaction include dichloromethane, chloroform, carbon tetrachloride, tetrachloroethane and the like. The reaction system is not particularly limited, and may be, for example, a batch system, a semi-batch system or a continuous system, but is usually performed in a batch system.

After completion of the reaction, the method for isolating the desired chlorinated aromatic compound from the reaction mixture is arbitrary, and can be isolated and obtained by a conventional method such as distillation or crystallization.

[0035]

The present invention will now be described more specifically with reference to examples. Note that the present invention is not limited at all by these examples.

Example 1 30 units equipped with a stirrer, thermometer, gas injection pipe and reflux cooling pipe
In a 0 ml four-necked flask, 184 g (2.0 mol) of toluene previously dehydrated to a water content of 7.5 ppm (measured by a Karl Fischer method moisture meter) with a molecular sieve, and 0.185 g of aluminum chloride (0.1 wt. 1% by weight;), and at a reaction temperature of 50 ° C., chlorine (moisture ratio: 4 ppm) was added at 1.56 g / min (0.22 mol).
The reaction was carried out for 1 hour while blowing at a flow rate of (/ min) (the total amount of water in the raw material and chlorine relative to aluminum chloride was 0.070 in a molar ratio). After the reaction was completed, the obtained reaction solution was analyzed by gas chromatography. As a result, the conversion of toluene was 54.8%, the production of o-chlorotoluene was 33.1%, and the production of p-chlorotoluene was 16%. .7
%, The dichlorotoluene production rate is 4.7%, and the o-chlorotoluene / p-chlorotoluene production ratio (hereinafter, o- / p
-Abbreviated as ratio) was 1.98.

Examples 2 to 6 The reaction was carried out in the same manner as in Example 1 except that the amount of water in toluene and the amount of aluminum chloride were changed. Table 1 shows the results.

[0038]

[Table 1]

Example 7 A reaction was carried out in the same manner as in Example 1 except that the amount of water in toluene was changed to 182 ppm (the total amount of water in the raw material and chlorine relative to aluminum chloride was 1.3 in a molar ratio.
5). As a result, the conversion of toluene was 61.7%, and o-
The production rate of chlorotoluene was 35.7%, the production rate of p-chlorotoluene was 24.9%, the production rate of dichlorotoluene was 0.6%, and the o- / p- ratio was 1.43.

Example 8 A reaction was carried out in the same manner as in Example 2 except that the amount of water in toluene was changed to 747 ppm (the total amount of water in the raw material and chlorine relative to aluminum chloride was 1.1 in terms of molar ratio).
0). As a result, the conversion of toluene was 57.7%, and o-
The production rate of chlorotoluene was 34.4%, the production rate of p-chlorotoluene was 22.7%, the production rate of dichlorotoluene was 0.4%, and the o- / p- ratio was 1.23.

Example 9 A reaction was carried out in the same manner as in Example 1 except that the reaction time was extended to 3 hours (molar ratio of aluminum chloride to water was 0.10). As a result, the conversion of toluene was 100.0% and the production of chlorotoluene was 20.0%.
7.1%, the yield of dichlorotoluene is 63.7%, and the selectivity of each isomer of dichlorotoluene is 2,6-isomer 2.
2.4%, 2,5-isomer 26.2%, 2,4-isomer 3
1.8%, 2,3-isomer 12.0%, 3,4-isomer 7.
6%.

Examples 10 to 14 The reaction was carried out in the same manner as in Example 7 except that the amount of water in toluene and the amount of aluminum chloride were changed respectively. Table 2 shows the results.

[0043]

[Table 2]

Example 15 A reaction was carried out in the same manner as in Example 9 except that the amount of water in toluene was changed to 182 ppm (the total amount of water in the raw material and chlorine relative to aluminum chloride was 1.3 in molar ratio).
9). As a result, the conversion of toluene was 100.0%, the production of chlorotoluene was 40.7%, the production of dichlorotoluene was 53.8%, and the selectivity of each isomer of dichlorotoluene was 2,2. 6-body 11.7%, 2,5-body 3
6.3%, 2,4-isomer 36.8%, 2,3-isomer 7.
0% and the 3,4-form were 8.2%.

Example 16 A reaction was carried out in the same manner as in Example 10 except that the amount of water in toluene was changed to 747 ppm (the total amount of water in the raw material and chlorine relative to aluminum chloride was 1.1 in terms of molar ratio).
1). As a result, the conversion of toluene was 100.0%, the production of chlorotoluene was 32.1%, the production of dichlorotoluene was 62.9%, and the selectivity of each isomer of dichlorotoluene was 2, 6-body 11.7%, 2,5-body 3
6.3%, 2,4-form 37.4%, 2,3-form
6% and 3,4-form 8.1%.

[0046]

According to the production method of the present invention, an o-chloroaromatic compound or a 2,6-dichloroaromatic compound can be obtained with high selectivity in a chlorination reaction of an aromatic compound. . Further, according to the production method of the present invention, in a chlorination reaction of an aromatic compound, a p-chloro aromatic compound or a 2,5-dichloro aromatic compound can be obtained with high selectivity.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomotake Asawa, 161 Kambara, Kambara-cho, Abara-gun, Shizuoka Prefecture Nippon Light Metal Co., Ltd. Inside the Kambara Factory (72) Inventor Hiroshi Ado 161 Kambara, Kambara-cho, Anbara-gun, Abara-gun, Shizuoka Prefecture Nippon Light Metal Co., Ltd. Kambara Factory F-term (reference)

Claims (20)

[Claims] (1) The following formula (I): (Wherein, R represents a lower alkyl group having 1 to 4 carbon atoms)
Is chlorinated in the presence of a Lewis acid catalyst to give an aromatic hydrocarbon represented by the following formula (II): In the method for producing a chlorinated aromatic compound represented by, the total amount of water in the raw material liquid and the chlorinating agent with respect to the Lewis acid catalyst is less than 1.0 by mole ratio of the chlorinated aromatic compound, Manufacturing method. 2. The amount of the Lewis acid catalyst is 0.0
The method for producing a chlorinated aromatic compound according to claim 1, wherein the amount is from 01% by weight to 10.0% by weight. 3. The process for producing a chlorinated aromatic compound according to claim 1, wherein the Lewis acid is aluminum chloride. 4. The aromatic hydrocarbon represented by the formula (I) is toluene, and the chlorinated aromatic compound represented by the formula (II) is o-
The process for producing a chlorinated aromatic compound according to any one of claims 1 to 3, wherein the process is chlorotoluene. 5. The chlorinated aromatic compound represented by the formula (II) is chlorinated in the presence of a Lewis acid catalyst,
I) In the method for producing a chlorinated aromatic compound represented by, the total amount of water in the raw material liquid and the chlorinating agent with respect to the Lewis acid catalyst is less than 1.0 by mole ratio of the chlorinated aromatic compound, Manufacturing method. 6. The amount of the Lewis acid catalyst is 0.0
The method for producing a chlorinated aromatic compound according to claim 5, wherein the amount is from 01% by weight to 10.0% by weight. 7. The method for producing a chlorinated aromatic compound according to claim 5, wherein the Lewis acid is aluminum chloride. 8. The chlorinated aromatic compound represented by the formula (II) is o-chlorotoluene, and the chlorinated aromatic compound represented by the formula (III) is 2,6-dichlorotoluene. The method for producing a chlorinated aromatic compound according to any one of claims 5 to 7. 9. The method for producing a chlorinated aromatic compound represented by the formula (III) by chlorinating the aromatic hydrocarbon represented by the formula (I) in the presence of a Lewis acid catalyst, A method for producing a chlorinated aromatic compound, characterized in that the total amount of water in the raw material liquid and the chlorinating agent is less than 1.0 in terms of mole ratio. 10. The amount of the Lewis acid catalyst is 0.1 to the raw material liquid.
The method for producing a chlorinated aromatic compound according to claim 9, wherein the amount is from 001% by weight to 10.0% by weight. 11. The process for producing a chlorinated aromatic compound according to claim 9, wherein the Lewis acid is aluminum chloride. 12. The method according to claim 9, wherein the aromatic hydrocarbon represented by the formula (I) is toluene and the chlorinated aromatic compound represented by the formula (III) is 2,6-dichlorotoluene. 12. The method for producing a chlorinated aromatic compound according to any one of items 11 to 11. 13. An aromatic hydrocarbon represented by the above formula (I) is chlorinated in the presence of a Lewis acid catalyst to give the following formula (IV): In the method for producing a chlorinated aromatic compound represented by, the total amount of water in the raw material liquid and the chlorinating agent with respect to the Lewis acid catalyst is 1.0 or more by mole ratio of the chlorinated aromatic compound Manufacturing method. 14. The Lewis acid catalyst is used in an amount of 0.1 to the starting solution.
The method for producing a chlorinated aromatic compound according to claim 13, wherein the amount is from 001% by weight to 10.0% by weight. 15. The method for producing a chlorinated aromatic compound according to claim 13, wherein the Lewis acid is aluminum chloride. 16. The aromatic hydrocarbon represented by the formula (I) is toluene, and the chlorinated aromatic compound represented by the formula (IV) is p
-Chlorotoluene, characterized in that it is chlorotoluene.
16. The method for producing a chlorinated aromatic compound according to any one of 15. 17. An aromatic hydrocarbon represented by the above formula (I) is chlorinated in the presence of a Lewis acid catalyst to give the following formula (V): In the method for producing a chlorinated aromatic compound represented by, the total amount of water in the raw material liquid and the chlorinating agent with respect to the Lewis acid catalyst is 1.0 or more by mole ratio of the chlorinated aromatic compound Manufacturing method. 18. The amount of the Lewis acid catalyst is 0.1 to the raw material liquid.
The method for producing a chlorinated aromatic compound according to claim 17, wherein the amount is from 001% by weight to 10.0% by weight. 19. The process for producing a chlorinated aromatic compound according to claim 17, wherein the Lewis acid is aluminum chloride. 20. The method according to claim 17, wherein the aromatic hydrocarbon represented by the formula (I) is toluene and the chlorinated aromatic compound represented by the formula (V) is 2,5-dichlorotoluene. 20. The method for producing a chlorinated aromatic compound according to any one of claims 19 to 19.