JPH06100520A - Production of 2,3-butadienenitrile - Google Patents

Abstract

PURPOSE:To industrially produce 2,3-butadienenitrile useful as an intermediate for medicines, agrichemicals and photographic chemicals. CONSTITUTION:2,3-Dichloropropene is reacted with prussic acid at pH6-8 to produce 2,3-butadienenitrile by one process and 2,3-dichloropropene is reacted with prussic acid at pH3-8 and successively with a base to give 2,3- butadienenitrile.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing 2,3-butadiene nitrile by reacting 2,3-dichloropropene with hydrocyanic acid.

[0002]

2. Description of the Related Art Conventionally, as a method for producing 2,3-butadiene nitrile, a method of reacting 3-bromo-3-butenonitrile obtained from 2,3-dibromopropene and a cyanide compound with sodium carbonate (Compt. Rend. 253,676 (1961) and 255,3424 (1962)), a method of reacting propargyl halide with hydrocyanic acid or an alkali metal cyanide compound (Co
mpt. Rend. 259, 1142 (1964)) was known.

However, according to the method, the yield of 3-bromo-3-butenonitrile from 2,3-dibromopropene is increased.
The method of 26% has a problem that propargyl halide, which has a risk of explosion, must be used in the method of 26%, and both methods are not necessarily sufficient as industrial manufacturing methods.

[0004]

The object of the present invention is to use industrially readily available 2,3-dichloropropene as a starting material without using a propargyl halide having a risk of explosion in one step or 3-chloro-. An object of the present invention is to provide an industrial production method for obtaining a desired product, 2,3-butadiene nitrile, in a good yield by a process in which 3-butenonitrile is intermediate.

[0005]

Means for Solving the Problems That is, the present invention is
A method for directly obtaining 2,3-butadiene nitrile by reacting 3-dichloropropene with hydrocyanic acid, or reacting 2,3-dichloropropene with hydrocyanic acid to produce an intermediate 3-
Chloro-3-butenonitrile was obtained, which was either isolated or, without isolation, directly reacted with base to give 2,
A method for obtaining 3-butadiene nitrile is provided.

The present invention will be described in detail below. The first aspect of the present invention is to react 2,3-dichloropropene and hydrocyanic acid at pH 6 to 8 in the presence of water and a monovalent copper salt to give 2,3
A method for producing butadiene nitrile.

The starting material of the present invention, 2,3-dichloropropene, is well known and industrially available, and the amount of hydrocyanic acid to be reacted with it is 2,3-dichloropropene 1
It is usually 1 to 2 equivalents relative to equivalents. A monovalent copper salt is used as a catalyst in this reaction, and examples of the copper salt include cuprous chloride and cuprous cyanide. The amount used is a few
-It is usually 0.01 to 1 equivalent, preferably 0.05 to 0.3 equivalent, relative to 1 equivalent of dichloropropene. The amount of water used is usually 10 times or more the weight of the monovalent copper salt.
The reaction temperature is usually 50 to 100 ° C., preferably 80 to 85
℃.

The above-mentioned water is most preferably used as a reaction solvent, but in addition to this, polar solvents such as ethylene glycol, dimethylformamide and dimethylsulfoxide, aromatic hydrocarbon solvents typified by toluene, hexane and heptane are also used. The hydrocarbon solvent or a mixture thereof may be added to water. When these solvents are added to water and used, the amount used is 1 to 10 relative to 2,3-dichloropropene.
It is twice the weight. This reaction is usually carried out by a method in which 2,3-dichloropropene and hydrocyanic acid are added individually or as a mixture into a mixture of a solvent and a monovalent copper salt.

At this time, p in the reaction solution was added while dropping the base.
By carrying out the reaction while maintaining H at 6 to 8, 2,3-butadiene nitrile can be obtained in good yield. At this time, if the pH of the reaction solution is lower than 6, the amount of the target 2,3-butadienenitrile produced is small, and a large amount of the intermediate 3-chloro-3-butenonitrile is produced. Further, when the pH of the reaction solution is in the range of more than 8, tarring is so severe that the desired 2,3-butadiene nitrile is hardly obtained.

Examples of the base used for adjusting the pH include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, sodium carbonate, and the like.
Alkali metal carbonates or alkali metal carbonates such as sodium hydrogen carbonate, potassium carbonate and potassium hydrogen carbonate, alkaline earth metal carbonates such as calcium carbonate and magnesium carbonate, and alkali metal salts of lower carboxylic acids such as sodium formate and sodium acetate. Alkali metal alcoholates such as salts, sodium methylate, sodium ethylate, potassium butoxide or triethylamine,
Organic bases such as pyridine are mentioned. These bases are
It can be used as it is, or as an aqueous solution or a water suspension. Among these bases, calcium hydroxide and calcium carbonate are preferably used, and the amount of the base used is 1 equivalent of 2,3-dichloropropene.
It is 0.1 to 3 equivalents, preferably 1 to 2 equivalents.

In this reaction, copper powder may be used in combination with the above-mentioned monovalent copper salt. As the copper powder, a powder of about 30 to 100 mesh is usually used. When copper powder is used in combination, the amount used is up to about 0.5 equivalent per equivalent of monovalent copper salt. By using sodium iodide together,
The reaction rate can be improved, and when sodium iodide is used, the amount thereof is usually 0.5 equivalent, preferably up to about 0.05 equivalent, relative to 1 equivalent of 2,3-dichloropropene.

After completion of the reaction, filtration, which is a usual post-treatment method,
The liquid separation gives 2,3-butadienenitrile containing a small amount of 3-chloro-3-butenonitrile, but if necessary, operations such as extraction are carried out. When an organic solvent is used for the reaction and extraction, the target product can be taken out by distilling the solvent off from the solution of the above-mentioned nitriles obtained after the post-treatment. Furthermore, if necessary, 2,3-butadiene nitrile can be purified by means such as distillation.

Thus, when 2,3-dichloropropene and prussic acid are reacted at pH 6 to 8 in the presence of water and a monovalent copper salt, a small amount of 3-chloro-3-butenonitrile is added. 2,3-butadiene nitrile containing is obtained, but when this reaction is carried out in the range of pH 3 to less than 6,
3-Chloro-3-butenonitrile containing a small amount of 3-butadiene nitrile is obtained, and this 3-chloro-3-butenonitrile can be easily converted to 2,3-butadiene nitrile by reaction with a base.

The second aspect of the present invention is such 3-chloro-
A method for producing 2,3-butadiene nitrile from a reaction mixture containing 3-butenonitrile, which comprises adding 2,3-dichloropropene and hydrocyanic acid to pH in the presence of water and a monovalent copper salt.
A method for producing 2,3-butadiene nitrile, which comprises reacting in the range of 3 to 8 to obtain a reaction mixture containing 3-chloro-3-butenonitrile, and then reacting the reaction mixture with a base. The reaction between 2,3-dichloropropene and hydrocyanic acid in this method is the same as that described above except that the pH range is partially different.

As described above, in the reaction between 2,3-dichloropropene and hydrocyanic acid, the reaction rates of 3-chloro-3-butenonitrile and 2,3-butadienenitrile differ depending on the pH of the reaction solution. By reacting the base as it is without separating the mixture, only 3-chloro-3-butenonitrile in the mixture is converted to 2,3-butadiene nitrile by dehydrochlorination reaction,
As a result, directly from 2,3-dichloropropene and hydrocyanic acid
The nitrile can be produced more advantageously than the 3-butadiene nitrile is obtained. Therefore, this method is a reaction condition that produces a large amount of 3-chloro-3-butenonitrile.
It is more advantageously applied when the reaction of the first step is carried out at 3 or more and less than 6.

The base used in this reaction includes alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, sodium carbonate and sodium hydrogen carbonate. Alkali metal carbonate or alkali metal bicarbonate such as potassium carbonate and potassium hydrogen carbonate, alkaline earth metal carbonate such as calcium carbonate and magnesium carbonate, sodium methylate, sodium ethylate, alkali metal alcoholate such as potassium butoxide. Alternatively, an organic base such as triethylamine or pyridine can be used. These bases can be used as they are, or as an aqueous solution or an aqueous suspension. Among these bases, sodium hydroxide, potassium hydroxide and calcium hydroxide are preferably used, and calcium hydroxide is particularly preferable. The amount used is 1 equivalent of 3-chloro-3-butenonitrile in the reaction mixture,
It is 0.1 to 3 equivalents, preferably 0.5 to 1.5 equivalents, and more preferably 1 to 1.2 equivalents.

In the dehydrochlorination reaction which is the second step of this method, a base is added to the reaction mixture containing 3-chloro-3-butenonitrile obtained in the first step, or the reaction mixture and the base are put into a reactor. Usually, it is done in parallel. In this case, it is preferable to react with a base while adjusting the pH of the reaction solution to be in the range of 6 to 13.5. If the pH is less than 6, the reaction becomes slow, and if the pH of the reaction solution exceeds 13.5, the yield of 2,3-butadiene nitrile which is the target product becomes poor.

The reaction temperature is usually 0 to 100 ° C, preferably 10 to 50 ° C. This method is a method in which a reaction mixture containing 3-chloro-3-butenonitrile obtained by the reaction of 2,3-dichloropropene and hydrocyanic acid is used as it is for dehydrochlorination reaction.
Needless to say, the dehydrochlorination reaction can be carried out also when -chloro-3-butenonitrile is used as a raw material.

After completion of the reaction, filtration, which is a usual post-treatment method,
2,3-butadiene nitrile is obtained by liquid separation,
If necessary, operations such as extraction are performed. When an organic solvent is used for the reaction and extraction, the solvent can be distilled off from the nitrile solution obtained after the post-treatment to take out the desired product. Furthermore, if necessary, 2,3-butadiene nitrile can be purified by means such as distillation.

[0020]

INDUSTRIAL APPLICABILITY According to the method of the present invention, 2,3-dichloropropene, which is industrially easily available, can be directly or intermediately intervened via 3-chloro-3-butenonitrile without using propargyl halide which has a risk of explosion. 2,3-Butadiene nitrile can be obtained in good yield.

[0021]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples.

Example 1 Cuprous chloride 186.3 g (1.80 mol), copper powder 15.7 g (0.25 mol), water
To a 10 liter separable flask charged with 2400 g, under stirring, 97.2 g (3.60 mol) of prussic acid and 655.4 g (1.77 mol) of 20% calcium hydroxide slurry were co-injected to adjust the pH to 6.5. After that, the temperature was raised to 80 ℃ and 2,3-dichloropropene 1344g.
A mixed liquid of (12.00 mol) and hydrocyanic acid 388.8 g (14.40 mol) was added dropwise to the reaction mass at 80 ° C. over 3 hours. During this period, 2571.3 g (6.94 mol) of 20% calcium hydroxide slurry was added dropwise to adjust the pH to 6.0.
Keeped in the range of ~ 7.0. Keep it at the same temperature for 2 hours,
During this period, 20% calcium hydroxide slurry 398.9 g (1.08 mol)
Was added dropwise to maintain the pH in the range of 6.0 to 7.0. After completion of the reaction, the reaction mass cooled to 20 ° C. was filtered and separated into 531.9 g of a crude product containing 60.9 g (0.60 mol) of 3-chloro-3-butenonitrile and 371.1 g (5.70 mol) of 2,3-butadiene nitrile. 2,3-
A brown oil of butadiene nitrile was obtained. This coarse 2,3-
The brown oil of butadiene nitrile was distilled to obtain 352.0 g (5.41 mol, yield 45.1%) of 2,3-butadiene nitrile and 3-chloro-3.
-Contains 31.0 g (0.31 mol, 2.6% yield) of butenonitrile392.
1 g of fraction was obtained.

Example 2 Cuprous chloride 186.3 g (1.80 mol), copper powder 15.7 g (0.25 mol), water
To a 10 liter separable flask charged with 2400 g, 97.2 g (3.60 mol) of hydrocyanic acid and 580.7 g (1.57 mol) of 20% calcium hydroxide slurry were co-injected at 65 ° C. to adjust the pH to 3.5. After that, the temperature was raised to 80 ℃ and 2,3-dichloropropene 1344g.
A mixed solution of (12.00 mol) and hydrocyanic acid 388.8 g (14.40 mol) was added dropwise to the reaction mass at 80 ° C. over 4.5 hours. During this period, 1948.7 g (5.26 mol) of 20% calcium hydroxide slurry was added dropwise to adjust the pH to 3.
It was kept in the range of 3 to 3.9. Incubate at the same temperature for another 2 hours, during which 353.0 g (0.95 m) of 20% calcium hydroxide slurry
ol) was added dropwise to keep the pH in the range of 3.3-3.9. After completion of the reaction, the reaction mass cooled to 20 ° C. was filtered and separated into 985.6 g of 3-chloro-3-butenonitrile (9.71 mol, 2,0.9% yield based on 2,3-dichloropropene) and 2,3-butadiene. Nitrile 19.2 g (0.30 mol, yield based on 2,3-dichloropropene
There was obtained 1108.4 g of crude 3-chloro-3-butenonitrile brown oil containing 2.5%). This crude 3-chloro-3-butenonitrile brown oil (34.24 g) and water (120 g) were charged, and the pH of the reaction mixture in a 500 ml flask heated to 30 ° C was maintained at 9.4 to 10.0 while 28% sodium hydroxide aqueous solution (42.86 g). Sodium hydroxide (0.300 mol) was added dropwise over 8 hours. After the completion of dropping, the solution was allowed to stand and separate to obtain 20.15 g of a brown oil. The aqueous layer is then extracted with 120 g of dichloromethane and combined with the oil layer and distilled to contain 17.23 g (0.265 mol) of 2,3-butadiene nitrile.
19.95 g of distillate was obtained. Yield of 2,3-butadiene nitrile 7
It was 2.1% (based on 2,3-dichloropropene).

Example 3 A 50 ml flask heated to 30 ° C. was charged with 33.70 g of oil containing 30.49 g (0.30 mol) of 3-chloro-3-butenonitrile and 2.46 g (0.04 mol) of 2,3-butadiene nitrile and 120 g of water. 40.50 g of 28% sodium hydroxide aqueous solution (0.28 mol of sodium hydroxide) is added while keeping the pH of the reaction solution inside at 8.9 to 9.5.
It was added dropwise over 7 hours. After the completion of dropping, the solution was allowed to stand and separate to obtain 19.57 g of a brown oil. The aqueous layer is then dichloromethane 12
It was extracted with 0 g and distilled together with the oil layer to obtain 20.40 g of a fraction containing 19.14 g (0.294 mol, yield 86.5%) of 2,3-butadiene nitrile.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Saito 3-1,98 Kasugade, Konohana-ku, Osaka-shi, Osaka Sumitomo Chemical Co., Ltd.

Claims (3)

[Claims] 1. A method for producing 2,3-butadiene nitrile, which comprises reacting 2,3-dichloropropene and hydrocyanic acid in the presence of water and a monovalent copper salt at a pH range of 6 to 8. 2. A reaction between 2,3-dichloropropene and hydrocyanic acid in the presence of water and a monovalent copper salt in the range of pH 3 to 8
A reaction mixture containing -chloro-3-butenonitrile,
Then, a method for producing 2,3-butadiene nitrile, which comprises reacting a base with the reaction mixture. 3. A process for producing 2,3-butadienenitrile, which comprises reacting 3-chloro-3-butenonitrile with a base.