JP3019116B2 - Method for producing N-chloroaromatic carboxylic acid amide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing N-chloroaromatic carboxylic acid amide from aromatic carboxylic acid amide. N-chloroaromatic carboxylic acid amide is an important substance as an intermediate for producing a herbicide or an agricultural chemical, or an intermediate for producing an aromatic amine compound used as a plastic material.

[0002]

2. Description of the Related Art A method for producing N-chloroaromatic carboxylic acid amide from aromatic carboxylic acid amide is disclosed in Japanese Patent Application Laid-Open No. 49-125331, in which a terephthalic acid amide or a dilute mineral acid acidic aqueous suspension of isophthalic amide is used. The chlorination reaction is carried out in a liquid, and the dilution of the reaction mixture is adjusted so that the hydrogen chloride generated during the chlorination reaction remains almost completely dissolved in the reaction mixture until the completion of the reaction. Have been. In this method, the yield of N-chloroaromatic carboxylic acid amide is as high as 92 to 99%, but the crystal of N-chloroaromatic carboxylic acid amide formed by the reaction is extremely fine and bulky, so that the operability is low. It is difficult to industrialize.

[0003]

The inventors of the present invention have studied the method for producing N-chloroaromatic carboxylic acid amide according to the above-mentioned Japanese Patent Application Laid-Open No. 49-125331, and have found the following problems. I knew it was there. Since the crystals of N-chloroaromatic carboxylic acid amide formed in the reaction are extremely fine and bulky, it is extremely difficult to separate N-chloroaromatic carboxylic acid amide generated from the reaction solution after the reaction by filtration. In addition, because of such fine crystals, if the concentration of the aromatic carboxylic acid amide at the time of preparation is increased, stirring becomes difficult with the progress of the chlorination reaction, and the reaction rate is reduced, so that unreacted substances released outside the reaction system are reduced. Chlorine increases. For this reason, the concentration of the aromatic carboxylic acid amide at the time of charging needs to be reduced to about 5%. An object of the present invention is to overcome these problems and to provide a method for industrially advantageously producing N-chloroaromatic carboxylic acid amide from aromatic carboxylic acid amide.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a method for producing N-chloroaromatic carboxylic acid amide having the above-mentioned problems, and as a result, the aromatic carboxylic acid amide was converted to chlorine in methyl alcohol. The inventors have found that N-chloroaromatic carboxylic acid amides having good stirring and filtration properties can be obtained in a high concentration and a high yield by the reaction, and the present invention has been achieved.

That is, according to the present invention, the general formula is Z (CON
H ₂ ) _n (where Z is a benzene, biphenyl, diphenyl ether, diphenyl sulfone, diphenyl methane or naphthalene group, and n is an integer of 1 to 3) in methyl alcohol And a method for producing N-chloroaromatic carboxylic acid amide.

According to the present invention, the general formula is Z (CONHCl)
A method for producing an N-chloroaromatic carboxylic acid amide represented by _n (wherein, Z is a benzene, biphenyl, diphenyl ether, diphenylsulfone, diphenylmethane or naphthalene group, and n is an integer of 1 to 3) It is about. The aromatic carboxylic acid amide used as a raw material in the present invention is a carboxylic acid amide having a monocyclic, multicyclic or condensed-cyclic aromatic ring group such as benzene, biphenyl, diphenylether, diphenylsulfone, diphenylmethane or naphthalene group. Chloroaromatic carboxylic acid amides are obtained. Specific examples of the aromatic carboxylic acid amide as a raw material include benzamide, phthalic acid amide, isophthalic acid amide, terephthalic acid amide, 4,4′-biphenylcarboxylic acid amide, 4,4′-diphenylether dicarboxylic acid amide, 4,4 '-Diphenylsulfonedicarboxylic acid amide, 4,4'-diphenylmethanedicarboxylic acid amide, 2,6-naphthalenedicarboxylic acid amide and the like.

The present invention is to react the above-mentioned aromatic carboxylic acid amide with chlorine in methyl alcohol. Generally, the aromatic carboxylic acid amide is suspended and chlorine is introduced into vigorously stirred methyl alcohol to effect a chlorination reaction. Is preferably performed. Alcohols other than methyl alcohol, such as ethyl alcohol and propyl alcohol, cannot be used because the alcohol itself undergoes a chlorination reaction under the reaction conditions. The amount of methyl alcohol used with respect to the aromatic carboxylic acid amide is usually the concentration of the charged aromatic carboxylic acid amide in the reaction system because the aromatic carboxylic acid amide is a crystal under the reaction conditions of the present invention. Is 5 to 50%. If the amount of methyl alcohol used is too small, stirring in the reaction system becomes difficult, and if it is too large, it is economically undesirable.

[0008] The reaction temperature of the chlorination reaction is in the range of 0 to 50 ° C. If the reaction temperature is too high, N-chloroaromatic carboxylic acid amide generated in the reaction is decomposed and the yield decreases. If the reaction temperature is too low, the reaction rate will decrease. Although the reaction time cannot be determined unconditionally depending on the type and amount of the aromatic carboxylic acid amide and the reaction temperature, it is generally 0.5 to 10 hours. The reaction of the present invention can be carried out under normal pressure or under pressure.

The crystals of N-chloroaromatic carboxylic acid amide formed in the reaction are cooled and separated after the reaction, and then easily separated and recovered by distilling off by-product hydrogen chloride and methyl alcohol under reduced pressure or by filtration. can do. According to the method of the present invention, N-chloroaromatic carboxylic acid amide crystals having good stirring and filtering properties can be obtained, so that N-chloroaromatic carboxylic acid amide can be produced at a high concentration and a high yield. The reaction of the present invention can be carried out by either a batch system or a continuous system.

[0010]

Next, the present invention will be described in detail with reference to examples. However, the present invention is not limited by these examples.

Example 1 82.1 g of isophthalamide and 500 ml of methyl alcohol were placed in a 1-liter three-necked flask equipped with a stirrer, a thermometer, and a chlorine introducing tube, and 82 g of chlorine was added to 5 ml of vigorous stirring at 5 ° C. Introduced in time. The crystals obtained by the reaction were relatively large and had good stirring and filtering properties. After the reaction was completed, the crystals in the reaction solution were filtered, washed with a small amount of methyl alcohol, and dried to obtain 116.3 g of white crystals. When the crystals were analyzed by liquid chromatography, the content of N, N'-dichloroisophthalamide was 98.7% by weight, and the yield based on the starting material isophthalamide was 98.4 mol%.

Example 2 In a device similar to that of Example 1, 121.1 g of benzamide and 450 ml of methyl alcohol were charged, and 76.5 g of chlorine was introduced at 20 ° C. with vigorous stirring for 1 hour.
The crystals obtained by the reaction were relatively large and had good stirring and filtering properties. After completion of the reaction, by-product hydrogen chloride and methyl alcohol were distilled off under reduced pressure to obtain white crystals.
4 g were obtained. When the crystals were analyzed by liquid chromatography, the content of N-chlorobenzaldehyde was 9%.
The amount was 9.4 wt%, and the yield based on the starting material benzamide was 99.4 mol%.

EXAMPLE 3 82.1 g of terephthalamide was added to the same apparatus as in Example 1.
And 500 ml of methyl alcohol, and 78.0 g of chlorine was introduced over 2 hours with vigorous stirring at 5 ° C.
The crystals obtained by the reaction were relatively large and had good stirring and filtering properties. After completion of the reaction, the crystals in the reaction solution were filtered, washed with a small amount of methyl alcohol, and dried to obtain 116.2 g of white crystals. When the crystals were analyzed by liquid chromatography, the content of N, N'-dichloroterephthalamide was 98.9% by weight, and the yield based on the starting material terephthalamide was 98.5 mol%.

Example 4 In the same apparatus as in Example 1, 51.2 g of 4,4'-diphenyletherdicarboxylic acid amide and methyl alcohol 5
Add 100 ml of chlorine, and vigorously stir at 10 ° C.
8.3 g were introduced in 5 hours. The crystals obtained by the reaction were relatively large and had good stirring and filtering properties. After the reaction was completed, the crystals in the reaction solution were filtered, washed with a small amount of methyl alcohol, and dried to obtain 64.5 g of white crystals. The crystals were analyzed by liquid chromatography to find that 4,4′-diphenyletherdicarboxylic acid-bis-
The content of N-chloroamide was 93.4 wt%,
The yield based on 4,4′-diphenyl ether dicarboxylic amide was 92.6 mol%.

Example 5 In a device similar to that of Example 1, 42.8 g of 2,6-naphthalenedicarboxylic acid amide and 500 ml of methyl alcohol were added, and 39.7 g of chlorine was added at 5 ° C. with vigorous stirring for 5 hours. Introduced in. The crystals obtained by the reaction were relatively large and had good stirring and filtering properties. After the reaction was completed, the crystals in the reaction solution were filtered, washed with a small amount of methyl alcohol, and dried to obtain 56.9 g of white crystals. The crystals were analyzed by liquid chromatography to find that the content of 2,6-naphthalenedicarboxylic acid-bis-N-chloroamide was 91.8 wt%, and the yield based on the starting material, 2,6-naphthalenedicarboxylic acid amide, was 92.0 wt%. It was 2 mol%.

[0016]

As shown in the examples, the method of the present invention can provide N-chloroaromatic carboxylic acid amide crystals having a suitable stirring property and filterability in a high yield. Therefore, according to the present invention, N-chloro aromatic carboxylic acid amide can be produced industrially very advantageously, and the present invention has great industrial significance.

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Claims (1)

(57) [Claims] (1) The general formula is Z (CONH ₂ ) _n (where Z is benzene, biphenyl, diphenyl ether,
N-chloroaromatic carboxylic acid characterized by reacting an aromatic carboxylic acid amide represented by diphenylsulfone, diphenylmethane or naphthalene group with n being an integer of 1 to 3) in chlorine in methyl alcohol. Method for producing amide