JP3146674B2 - Method for producing 2,3-butadiene nitrile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process 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 2,3-dibromopropyl and 3-bromo-3-butenonitrile obtained from a hydrocyanic acid 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 (Co
mpt. Rend. 259, 1142 (1964)).

[0003] However, according to the method, the yield of 3-bromo-3-butenonitrile from 2,3-dibromopropyl is increased.
The low method of 26% requires the use of explosive hazardous propargyl halides, and both methods are not always satisfactory as industrial production methods.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a single step or 3-chloro-method starting from industrially available 2,3-dichloropropene without using explosive danger of propargyl halide. It is an object of the present invention to provide an industrial production method for obtaining the desired product, 2,3-butadienenitrile, at a high yield by a process involving intermediate 3-butenonitrile.

[0005]

That is, the present invention relates to the following:
A method of directly reacting 3-dichloropropene with hydrocyanic acid to obtain 2,3-butadiene nitrile, or a method of reacting 2,3-dichloropropene with hydrocyanic acid to form an intermediate 3-
Chloro-3-butenonitrile was obtained, which was isolated or reacted without isolation with a base,
It is intended to provide a method for obtaining 3-butadiene nitrile.

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

The starting material of the present invention, 2,3-dichloropropene, is known and industrially easily available, and the amount of hydrocyanic acid to be reacted therewith is 2,3-dichloropropene 1
It is usually 1-2 equivalents to equivalents. In this reaction, a monovalent copper salt is used as a catalyst, and examples of the copper salt include cuprous chloride and cuprous cyanide. Its usage is a few
-It is generally 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 at least 10 times the weight of the monovalent copper salt.
The reaction temperature is usually 50-100 ° C, preferably 80-85.
° C.

The above-mentioned water is most preferably used as the reaction solvent. In addition, polar solvents such as ethylene glycol, dimethylformamide and dimethyl sulfoxide, aromatic hydrocarbon solvents such as toluene, hexane, heptane and the like are also used. Hydrocarbon solvents or mixtures thereof may be added to the water. When these solvents are added to water and used, the amount used is 1 to 10 with respect to 2,3-dichloropropene.
Weight times. This reaction is usually carried out by a method in which 2,3-dichloropropene and hydrocyanic acid are individually or separately added dropwise to a mixture of a solvent and a monovalent copper salt.

At this time, p is added to the reaction solution while dropping a base.
By carrying out the reaction while keeping 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 desired 2,3-butadiene nitrile is small, and a large amount of the intermediate, 3-chloro-3-butenonitrile, is generated. If the pH of the reaction solution is in the range of more than 8, tarring is so severe that the desired 2,3-butadienenitrile can hardly be obtained.

Bases 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 carbonate or alkali metal bicarbonate such as sodium hydrogen carbonate, potassium carbonate and potassium hydrogen carbonate, alkaline earth metal carbonate such as calcium carbonate and magnesium carbonate, alkali metal of lower carboxylic acid 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 exemplified. 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 use is based on 1 equivalent of 2,3-dichloropropene.
0.1 to 3 equivalents, preferably 1 to 2 equivalents.

In the present reaction, copper powder may be used in addition to the above-mentioned monovalent copper salt. Copper powder having a mesh of about 30 to 100 is usually used. When copper powder is used in combination, the amount used is up to about 0.5 equivalent to 1 equivalent of monovalent copper salt. Also, by using sodium iodide together
The reaction rate can be improved, and when sodium iodide is used, its use amount is usually 0.5 equivalent, preferably up to about 0.05 equivalent, per 1 equivalent of 2,3-dichloropropene.

After completion of the reaction, filtration, which is a usual post-treatment method,
Although 2,3-butadienenitrile containing a small amount of 3-chloro-3-butenonitrile is obtained by liquid separation, extraction and other operations are performed as necessary. When an organic solvent is used for the reaction and the extraction, the desired product can be obtained by removing the solvent from the above-mentioned nitrile solution obtained after the post-treatment. If necessary, 2,3-butadiene nitrile can be purified by means such as distillation.

Thus, when 2,3-dichloropropene and hydrocyanic acid are reacted at a pH of 6 to 8 in the presence of water and a monovalent copper salt, a small amount of 3-chloro-3-butenonitrile is converted. 2,3-butadiene nitrile is obtained, but when this reaction is carried out in the range of pH 3 to less than 6, 2,3-butadiene nitrile is obtained.
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 relates to such a 3-chloro-
A method for producing 2,3-butadiene nitrile from a reaction mixture containing 3-butenonitrile, comprising preparing 2,3-dichloropropene and hydrocyanic acid in the presence of water and a monovalent copper salt at pH
This is a process for producing 2,3-butadiene nitrile, which comprises reacting the reaction mixture 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 described above except that the pH range is partially different.

As described above, in the reaction between 2,3-dichloropropene and hydrocyanic acid, the production ratio of 3-chloro-3-butenonitrile and 2,3-butadienenitrile varies depending on the pH of the reaction solution. By reacting the mixture as it is without separating the mixture, only 3-chloro-3-butenonitrile in the mixture is converted to 2,3-butadiene nitrile by a dehydrochlorination reaction,
As a result, 2,3-dichloropropene and hydrocyanic acid
The nitrile can be produced more advantageously than obtaining 3-butadiene nitrile. Therefore, this method is a reaction condition under which a large amount of 3-chloro-3-butenonitrile is produced.
It is more advantageously applied when the reaction of the first step is performed in 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, sodium hydrogen carbonate, and the like. Alkali metal carbonate or alkali metal bicarbonate such as potassium carbonate and potassium bicarbonate; alkaline earth metal carbonate such as calcium carbonate and magnesium carbonate; alkali metal alcoholate such as sodium methylate, sodium ethylate and potassium butoxide Alternatively, an organic base such as triethylamine and pyridine can be used. These bases can be used as they are, or as an aqueous solution or suspension. Of these bases, sodium hydroxide, potassium hydroxide and calcium hydroxide are preferably used, and calcium hydroxide is particularly preferred. The amount used is based on 1 equivalent of 3-chloro-3-butenonitrile in the reaction mixture.
0.1 to 3 equivalents, preferably 0.5 to 1.5 equivalents, more preferably 1 to 1.2 equivalents.

In the second step of this method, the dehydrochlorination reaction, 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 added to a reactor. During, it is usually done concurrently. In this case, it is preferable to react with the base while adjusting the pH of the reaction solution to be in the range of 6 to 13.5. When the pH is less than 6, the reaction becomes slow, and when 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 0-100 ° C, preferably 10-50 ° C. In this method, a reaction mixture containing 3-chloro-3-butenonitrile obtained by a reaction between 2,3-dichloropropene and hydrocyanic acid is directly used for a dehydrochlorination reaction.
It goes without saying that the dehydrochlorination reaction can be carried out also in the case of using -chloro-3-butenonitrile as a raw material.

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

[0020]

According to the method of the present invention, 2,3-dichloropropene which is industrially available without using explosive hazardous propargyl halide is directly or intermediately via 3-chloro-3-butenonitrile. 2,3-Butadiene nitrile can be obtained in good yield.

[0021]

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

Example 1 186.3 g of cuprous chloride (1.88mol), Copper powder 15.7g (0.25mol), water
Stir into a 10-liter separable flask containing 2400 g.
Under stirring, at 65 ° C, 97.2 g (3.60 mol) of hydrocyanic acid and 20% calcium hydroxide
655.4 g (1.77 mol) of the slurry at the same time to adjust the pH to 6.5.
Was. After that, the temperature was raised to 80 ° C and 2,3-dichloropropene1332g
(12.00 mol) and 388.8 g (14.40 mol) of hydrocyanic acid
The solution was added dropwise at 80 ° C. over 3 hours. During this time, 20%
2571.3 g (6.94 mol) of the lithium slurry was added dropwise to adjust the pH to 6.0.
~ 7.0. Keep at the same temperature for another 2 hours,
During this time, 398.9 g (1.08 mol) of 20% calcium hydroxide slurry
Was added dropwise to maintain the pH in the range of 6.0 to 7.0. End of reaction
Then, the reaction mass cooled to 20 ° C. was filtered, separated, and
B-3-butenonitrile 60.9g (0.60mol) and 2,3-butamate
531.9 g of crude 2,3- containing 371.1 g (5.70 mol) of diennitrile
A brown oil of butadiene nitrile was obtained. This crude 2,3-
Distill the brown oil of butadiene nitrile to 2,3-butadiene
352.0 g (5.41 mol, 45.1% yield) of ennitrile and 3-chloro-3
-Contains 31.0 g (0.31 mol, 2.6% yield) of butenonitrile392.
1 g of a fraction was obtained.

Example 2 186.3 g of cuprous chloride (1.88mol), Copper powder 15.7g (0.25mol), water
Stir into a 10-liter separable flask containing 2400 g.
Under stirring, at 65 ° C, 97.2 g (3.60 mol) of hydrocyanic acid and 20% calcium hydroxide
580.7 g (1.57 mol) of the slurry was added simultaneously to adjust the pH to 3.5.
Was. After that, the temperature was raised to 80 ° C and 2,3-dichloropropene1332g
(12.00 mol) and 388.8 g (14.40 mol) of hydrocyanic acid
The solution was added dropwise at 80 ° C. over 4.5 hours. 20% hydroxylation during this time
1948.7 g (5.26 mol) of calcium slurry was added dropwise to adjust the pH to 3.
It was kept in the range of 3 to 3.9. Keep at the same temperature for another 2 hours
During this time, 353.0 g of 20% calcium hydroxide slurry (0.95 m
ol) was added dropwise to maintain the pH in the range of 3.3 to 3.9. End of reaction
After the reaction, the reaction mass cooled to 20 ° C is filtered, separated, and
985.6 g of roro-3-butenonitrile (9.71 mol, 2,3-dichloro)
80.9% yield based on lopropene) and 2,3-butadiennit
Lil 19.2 g (0.30 mol, 2,3-dichloropropene-based yield
1108.4 g of crude 3-chloro-3-butenonitrile
Brown oil was obtained. This crude 3-chloro-3-butenonit
Charge 34.24g of Lil brown oil and 120g of water and raise the temperature to 30 ℃
Keep the pH of the reaction solution in the 500 ml flask kept at 9.4 to 10.0.
42.86 g of 28% aqueous sodium hydroxide solution
(0.300 mol of lithium) was added dropwise over 8 hours. Drip end
Thereafter, the mixture was allowed to stand still to obtain 20.15 g of a brown oil. Then water
Extract the layer with 120 g of dichloromethane and combine with the oil layer
Distilled and contains 17.23 g (0.265 mol) of 2,3-butadiene nitrile
19.95 g of fraction was obtained. 2,3-butadiene nitrile yield72
%(Based on 2,3-dichloropropene).

Example 3 A 50 ml flask charged with 33.70 g of an 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 was heated to 30 ° C. While maintaining the pH of the reaction solution at 8.9 to 9.5, 40.50 g of a 28% aqueous sodium hydroxide solution (0.28 mol of sodium hydroxide) was added.
It was added dropwise over 7 hours. After completion of the dropwise addition, the mixture was allowed to stand and separated to obtain 19.57 g of a brown oil. The aqueous layer was then diluted with dichloromethane 12
It was extracted with 0 g and distilled together with the oil layer to obtain a fraction of 20.40 g containing 19.14 g (0.294 mol, yield 86.5%) of 2,3-butadiene nitrile.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // C07B 61/00 300 C07B 61/00 300 (72) Inventor Kenji Saito 3-1-1 Kasuganaka, Konohana-ku, Osaka-shi, Osaka No. 98 Sumitomo Chemical Co., Ltd. (56) References JP-A-5-194348 (JP, A) JP-A-5-194349 (JP, A) Compt. Rend. , 1962, Vol. 255, p3424-26 Compt. Rend. , 1961, Vol. 253, p676-7 Bull. Soc. Chem. , 1959, p1268 (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 253/14 B01J 27/122 B01J 27/26 C07C 253/30 C07C 255/07 C07B 61/00 300 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A process for producing 2,3-butadiene nitrile, comprising reacting 2,3-dichloropropene with hydrocyanic acid in the presence of water and a monovalent copper salt in the pH range of 6 to 8.