JP2001039936A - Production of aromatic dicarboxylic acid diamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To industrially advantageously obtain the subject compound in a high yield hardly causing a by-product of carboxylic acid by amidating an aromatic dinitrile in the presence of an inorganic strong base in water-containing dimethyl sulfoxide. SOLUTION: An aromatic dinitrile (e.g. benzenedinitrile, etc.), is amidated in the presence of an inorganic strong base (preferably sodium hydroxide) in water-containing dimethyl sulfoxide to give the objective compound. The amount of the inorganic strong base used is preferably 0.01-1 mol based on 1 mol of the aromatic dinitrile. The amount of water used is preferably 1.5-50 mols based on 1 mol of nitrile group. The amount of dimethyl sulfoxide is preferably an amount to make the preparation concentration of the aromatic dinitrile 1-50 wt.%. Preferably the reaction temperature of the amidation is 50-150 deg.C and the reaction time is 0.5-10 hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an aromatic dicarboxylic diamide from an aromatic dinitrile. Aromatic dicarboxylic acid diamide is a starting material for aromatic diamine and aromatic diisocyanate, which are raw materials for producing polyamide resin and polyurethane resin.

[0002]

2. Description of the Related Art Aromatic dicarboxylic diamides can be chlorinated to form chloramides and then subjected to Hoffman rearrangement in the presence of water to produce aromatic diamines, which are used as raw materials for polyamide resins. On the other hand, an aromatic dicarbamic acid diester is synthesized by performing Hoffmann rearrangement in the presence of an alcohol, and this is thermally decomposed to produce an aromatic diisocyanate, which is a raw material for a polyurethane resin.
Various methods have been proposed for producing aromatic carboxylic acid amides from aromatic nitriles. For example, Org.Syn.Coll.Vo
l. 2,586-587 (1943) describes a process for amidating o-tolunitrile with hydrogen peroxide. This method has a problem that a large amount of expensive hydrogen peroxide is used as an auxiliary material. British Patent Nos. 1133013 and 13515130 describe a process for amidating nitrile compounds using manganese dioxide as a catalyst. This method requires a large amount of catalyst, and furthermore, the generated aromatic carboxylic acid amide precipitates as crystals and blocks active points of the catalyst, so that there is a problem in the life of the catalyst.

Further, US Pat. No. 3,763,235 discloses a process for amidating a nitrile compound using a water-containing lower aliphatic carboxylic acid in the presence of a metal salt. This method also requires a large amount of a catalyst, and has a difficulty in this separation because the catalyst is entrapped in the crystals of the precipitated aromatic carboxylic acid amide. WO 90/09988 discloses a method of contacting an aromatic nitrile with an alkali metal perborate in a water-containing alcohol. In this method, there is a problem in that an expensive alkali metal perborate must be used as an auxiliary material in a large amount of 2.5 to 4 mol per 1 mol of the aromatic nitrile as a raw material. JP-A-6-116221 and JP-A-6-128204 disclose a method of amidating aromatic nitrites in an alcohol containing water in the presence of a strong inorganic base and the presence of a strong inorganic base in an aromatic nitrile. Below, a method is disclosed in which an imino ether compound is synthesized by reacting with an alcohol and then amidated by adding water.

[0004]

The above-mentioned JP-A-6-116221
Are industrially superior in that inexpensive alkali metal hydroxides and alcohols are used as catalysts, but the inventors studied the amidation of terephthalonitrile. As a result, a considerable amount of terephthalic acid by-product was confirmed in the reaction product.
(Comparative Example 1). The by-product carboxylic acid is consumed as a salt of the carboxylic acid with the inorganic strong base added to the reaction system. In addition, when the amine compound and the isocyanate compound are synthesized by the above-described Hoffman rearrangement method using a carboxylic acid amide containing a carboxylic acid or a carboxylic acid salt as a raw material, the carboxylic acid or the salt of the carboxylic acid is included in the product. Therefore, it is necessary to separate the carboxylic acid amide from the carboxylic acid.

As described above, the conventional method for producing an aromatic dicarboxylic acid diamide from an aromatic dinitrile requires a large amount of expensive auxiliary raw materials and catalysts, and requires a purification step because many carboxylic acids are by-produced. However, it is difficult to say that this method is necessarily industrially satisfactory. An object of the present invention is to provide a method for industrially advantageously producing an aromatic dicarboxylic acid diamide from an aromatic dinitrile.

[0006]

The present inventors have conducted intensive studies on the amidation of aromatic dinitrile having the above-mentioned problems, and as a result, have found that aromatic dinitrile and water can be converted into water in the presence of a strong inorganic base and dimethyl sulfoxide. The present inventors have found that by performing the reaction, there is almost no by-product of carboxylic acid, and an aromatic dicarboxylic acid diamide can be obtained in high yield, and the present invention has been achieved.

That is, the present invention is a process for producing an aromatic dicarboxylic acid diamide, which comprises amidating an aromatic dinitrile in dimethyl sulfoxide containing water in the presence of a strong inorganic base.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The aromatic dinitrile used as a raw material in the method of the present invention includes benzene dinitrile, naphthylene dinitrile and the like. Phthalonitrile, isophthalonitrile, terephthalonitrile and naphthylene dinitrile can be obtained by various methods, but the synthesis method is not particularly limited. Industrially, for example, the corresponding aromatic dinitrile can be easily obtained by ammoxidation of xylene or dialkylnaphthalene, which can be used as a raw material.

As the inorganic strong base used as a catalyst in the present invention, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are usually used, but sodium hydroxide which is industrially available at low cost Is preferred. The amount of the inorganic strong base used is preferably in the range of 0.01 to 1 mol per 1 mol of aromatic dinitrile. When the amount of the inorganic strong base used is smaller than this, the reaction rate decreases, while when the amount used is larger, the reaction rate increases, but it is not economical.

In the method of the present invention, aromatic dinitrile is reacted with water in the presence of dimethyl sulfoxide and a strong inorganic base. The amount of water used is 1.5 to 1 mole of the nitrile group.
A range of ５０50 mol is preferred. If the amount of water is less than this, the amidation reaction of the aromatic dinitrile will not be completed,
If the amount of water is larger than this, the aromatic dicarboxylic acid diamide produced by the reaction is hydrolyzed to produce carboxylic acid as a by-product, so that the yield of aromatic dicarboxylic acid diamide decreases in all cases. The amount of dimethyl sulfoxide used with respect to the aromatic dinitrile is determined by the fact that the aromatic dinitrile of the present invention and the product aromatic dicarboxylic acid diamide are often crystalline under the reaction conditions. Preferably, the concentration is in the range of 1 to 50% by weight. If the amount is less than this range, stirring in the reaction system becomes difficult, while if it is more than this range, the space-time yield decreases.

The reaction temperature for amidation is preferably in the range of 50 to 150 ° C. If the reaction temperature is higher than this, the aromatic dicarboxylic acid diamide produced by the reaction is hydrolyzed and the by-product of carboxylic acid increases. On the other hand, if the reaction temperature is lower than this, the reaction rate decreases. The reaction time varies depending on the type of aromatic dinitrile, the type and amount of the strong inorganic base, the charging conditions of water and dimethylsulfoxide, the reaction temperature, and the like, and cannot be expressed unconditionally, but is usually 0.5 to 10 hours.

The aromatic dicarboxylic acid diamide formed in the reaction is cooled after the completion of the reaction, and can be easily separated and recovered from the reaction product by filtration. Since a small amount of active ingredients (strong inorganic base used as a catalyst, unreacted aromatic dinitrile, and aromatic dicarboxylic acid diamide as a reaction product) are dissolved in the filtrate after separation of the aromatic dicarboxylic acid diamide, The filtrate can be returned to the reaction system in order to increase the utilization efficiency of the catalyst and the yield of the reaction.

[0013]

The present invention will be described more specifically with reference to the following examples and comparative examples. However, the present invention is not limited to these examples.

Example 1 A 1-liter three-necked flask equipped with a stirrer and a thermometer was charged with 80 g of terephthalonitrile, 500 g of dimethyl sulfoxide, 64 g of a 1N aqueous sodium hydroxide solution and 30 g of water. At this time, the charged amount of sodium hydroxide to terephthalonitrile was 0.1 mole ratio, and the charged amount of water was 8.4 mole ratio. This flask was placed in an oil bath and stirred at 98 ° C. for 3 hours. After completion of the reaction, the reaction solution was cooled, filtered, washed with water, and dried under vacuum to obtain 98.6 g of white crystals. When the crystals were analyzed by liquid chromatography, the content of terephthalic acid amide was 99.6%, and terephthalic acid was not present in the crystals. The yield based on the starting material terephthalonitrile was 95.9%.

Example 2 An apparatus similar to that used in Example 1 was prepared by adding terephthalonitrile 40
g, dimethyl sulfoxide 500 g, and a 1N aqueous solution of sodium hydroxide 65 g. At this time, the charged amount of sodium hydroxide with respect to terephthalonitrile was 0.2
It is a molar ratio, and the charged amount of water is 11.5 molar ratio. This flask was placed in an oil bath and stirred at 97 ° C. for 3 hours. After the completion of the reaction, the reaction product was cooled, filtered, washed with water, and dried under vacuum to obtain 50.0 g of white crystals. When the crystals were analyzed by liquid chromatography, the content of terephthalic acid amide was 99.0%, and terephthalic acid was not present in the crystals. The yield based on the starting material terephthalonitrile was 96.6%.

Example 3 In a device similar to that of Example 1, 40 g of terephthalonitrile was added.
500 g of dimethyl sulfoxide and 65 g of a 1N aqueous solution of potassium hydroxide were charged. At this time, the charged amount of potassium hydroxide to terephthalonitrile was 0.2 mole ratio, and the charged amount of water was 11.5 mole ratio. This flask was placed in an oil bath and stirred at 97 ° C. for 3 hours.
After the completion of the reaction, the reaction product was cooled, filtered, washed with water, and vacuum dried to obtain 50.0 g of white crystals. When the crystals were analyzed by liquid chromatography, the content of terephthalic acid amide was 99.2%, and terephthalic acid was not present in the crystals. The yield based on the starting material terephthalonitrile was 95.6%.

Example 4 The same apparatus as in Example 1 was used except that isophthalonitrile 40
g, dimethyl sulfoxide (500 g) and a 1N aqueous solution of sodium hydroxide (65 g) were charged. At this time, the charged amount of sodium hydroxide to isophthalonitrile was 0.2 mole ratio, and the charged amount of water was 11.5 mole ratio. Place this flask in an oil bath,
Stirred for hours. After the completion of the reaction, the reaction product was cooled and analyzed by liquid chromatography. As a result, the yield of isophthalamide was 92.7%.

Example 5 In the same apparatus as in Example 1, 44.5 g of 1,5-naphthylenedinitrile (purity: 99.13%), 500 g of dimethyl sulfoxide, 50 g of 1N aqueous sodium hydroxide solution
And 25 g of water. At this time, the amount of sodium hydroxide charged to 1,5-naphthylene dinitrile was 0.20 mole ratio, and the amount of water charged was 16.9 mole ratio. The flask was placed in an oil bath, heated to a reaction temperature of 98 ° C. with stirring, and then kept for 3 hours. During this time, the reaction solution exhibited a homogeneous solution at a point when the temperature passed around 90 ° C., but after that, crystals were precipitated with the formation of amide to form a slurry. After completion of the reaction, the reaction product was filtered, rinsed with water, and dried to obtain 51.5 g of white crystals.
As a result of analyzing the crystals by liquid chromatography, 1,5
The content of -naphthylene dicarboxylic acid amide was 98.9%, and the yield based on 1,5-naphthylene dinitrile as the raw material was 96.0%.

Example 6 In the same apparatus as in Example 1, 44.5 g of 1,5-naphthylene dinitrile (purity: 99.13%), 550 g of dimethyl sulfoxide and 50 g of a 1N aqueous sodium hydroxide solution
And 50 g of water, and reacted at a reaction temperature of 97 ° C. for 3 hours. At this time, the charged amount of sodium hydroxide to 1,5-naphthylene dinitrile was 0.20 mole ratio, and the charged amount of water was 22.5 mole. After the reaction,
The reaction product was filtered, rinsed with water, and dried to obtain white crystals.
1.5 g were obtained. As a result of analyzing the crystals by liquid chromatography, the content of 1,5-naphthylene dicarboxylic amide was 99.4%, and the yield based on 1,5-naphthylene dinitrile as a raw material was 96.5%. Met.

Comparative Example 1 The same apparatus as in Example 1 was used except that terephthalonitrile 80 was used.
g, n-propanol (500 g) and 1N-sodium hydroxide aqueous solution (67 g) were charged. At this time, the amount of sodium hydroxide charged to terephthalonitrile was 0.1
Molar ratio, and the amount of water charged was 6.1 molar ratio. This flask was placed in an oil bath and stirred at 93 ° C. for 2 hours. After the reaction is completed, the reaction product is cooled, filtered, washed with water,
Vacuum drying yielded 84.1 g of white crystals. When the crystals were analyzed by liquid chromatography, the content of terephthalic acid amide was 93.1%, and the yield based on the starting material terephthalonitrile was 77.5%. 1.7% of terephthalic acid was contained in the crystal.

[0021]

As is clear from the above examples, according to the present invention, an aromatic dinitrile and water are reacted in the presence of a strong inorganic base and dimethyl sulfoxide to produce almost no by-product of aromatic dicarboxylic acid. And an aromatic dicarboxylic acid diamide can be produced in high yield. According to the method of the present invention, high-purity aromatic dicarboxylic diamide can be easily obtained without using expensive auxiliary materials or catalysts, and therefore, the industrial significance of the present invention is great.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yuji Matsunaga 182 Niigata, Niigata City, Niigata Prefecture F-term in Niigata Research Laboratory, Mitsubishi Gas Chemical Co., Ltd. (Reference) 4H006 AA02 AC53 AD15 AD17 BA02 BA29 BB22 BC10 BC34 BC35 BE60 BV71 4H039 CA71 CF40

Claims (2)

[Claims] (1) An aromatic dinitrile is prepared in the presence of a strong inorganic base.
A process for producing an aromatic dicarboxylic acid diamide, comprising amidating in dimethyl sulfoxide containing water. 2. The method for producing an aromatic dicarboxylic acid diamide according to claim 1, wherein the strong inorganic base is sodium hydroxide.