JPH05331126A - Production of 1,4-dicyano-2-butene - Google Patents

Abstract

PURPOSE:To quickly and selectively produce 1,4-dicyano-2-butene from 2- butene-1,4-diol or 3-butene-1,2-diol and hydrogen cyanide. CONSTITUTION:2-Butene-1,4-diol and/or 3-butene-1,2-diol is made to react with hydrogen cyanide in the presence of a catalyst consisting of copper (II) halide and a non-aromatic organic amine halogen acid salt.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a precursor of hexamethylenediamine, which is a raw material for 6,6-nylon and the like.
It relates to a method for producing 4-dicyano-2-butene.

[0002]

2. Description of the Related Art When 1,2-dicyano-2-butene is produced by reacting 2-butene-1,4-diol with hydrogen cyanide, a catalyst having cuprous halide supported on silica gel is used. Gas phase method (German Patent 2128)
001), liquid phase in the presence of copper bromide and alkali metal bromides (German Patent 2144390).
It has been known.

In the presence of a catalyst composed of cuprous halide and non-aromatic organic amine halogenate, 1,4-
The reaction between diacetoxy-2-butene and hydrogen cyanide is known (Japanese Patent Publication No. 47-29888). In addition to this, when 1,4-diacetoxy-2-butene is used, there are known some methods for performing cyanation using a cuprous halide-based catalyst (Japanese Patent Publication No. 47-29).
888, German Patent 2723778).

[0004]

However, in the conventional reaction between 2-butene-1,4-diol and hydrogen cyanide, in the case of a gas phase reaction, oligomers and other impurities are often produced, resulting in a low yield. In the case of aqueous solution reaction, the volume efficiency is poor, and it is difficult to say that this method is industrially preferable. Further, in the case of the reaction of 1,4-diacetoxy-2-butene with hydrogen cyanide, the reaction rate is not sufficient, cyanation does not proceed completely, and acetic acid has to be recovered from the reaction system, and also in terms of operation. This method is difficult to carry out industrially.

In view of such circumstances, the present inventors have
As a result of diligent studies on an industrially advantageous production method of dicyano-2-butene, 2-butene-1,4-diol or 3-butene-1,2-diol was replaced with a cuprous halide and a non-aromatic organic compound. When hydrogen cyanide is reacted in the presence of a catalyst composed of an amine halogenate, the reaction proceeds very rapidly and 1,4-dicyano-2-butene is obtained with good selectivity, and water is removed from the catalyst after completion of the reaction. It was found that the catalyst can be recycled by removing it, and that the deterioration of the catalyst can be suppressed by further removing water and reacting the used catalyst with hydrohalic acid, thus completing the present invention. did.

[0006]

That is, the present invention provides 2-butene-1,4-diol and / or 3-butene in the presence of a catalyst comprising a cuprous halide and a non-aromatic organic amine halogenate. Reacting 1,2-diol with hydrogen cyanide, and reusing after removing water from a used catalyst, or after removing water and reacting hydrohalic acid. -A method for producing dicyano-2-butene.

The 2-butene-1,4-diol or 3-butene-1,2-diol used in the present invention can be easily obtained by hydrolysis of diacetoxybutenes produced from butadiene and acetic acid by a known method. be able to. In the reaction, these can be used individually or as a mixture.

When carrying out the present invention, it is preferable to use a high concentration of hydrocyanic acid (water content is 10% by weight or less), and it is also possible to use anhydrous hydrogen cyanide. The cuprous halide used for the catalyst is preferably chloride or bromide.

As the non-aromatic organic amine halogenate, it is desirable to prepare a molten mixture of cuprous halide and anhydrous. For example, ammonium halides such as ammonium chloride and ammonium bromide, methylamine, dimethylamine, Hydrochlorides or hydrobromides of lower alkylamines such as triethylamine, ethylamine, diethylamine, triethylamine, etc. Hydrochlorides or amines of amines having a functional group inert to the reaction such as ethanolamine, diethanolamine, ethylenediamine, etc. Salt can be mentioned. Further, these amine halogenates may be used alone or in combination.

It is desirable that the amount of the catalyst used is large to some extent in consideration of the reaction rate.
It is selected from 0 to 200 mol%. Reaction temperature is about 2
It is carried out in the liquid phase at a temperature in the range 0-200 ° C, preferably about 60-140 ° C. This reaction can also be performed under pressure. It is desirable to carry out the reaction in an inert atmosphere such as nitrogen in order to suppress the oxidation of the copper catalyst. The reaction mixture is worked up by a conventional method. Usually, the product is extracted with a solvent such as ethyl acetate or toluene, and the solvent is distilled off to obtain the desired product. Also,
If necessary, the product may be purified by distillation or recrystallization,
Be used.

The used catalyst after separating the product by solvent extraction or the like can be reused as a catalyst after removing the contained water by vacuum distillation or the like. Since the used catalyst solidifies when left at room temperature for a long time, it is usually operated and stored at a temperature higher than room temperature. Reuse of the catalyst can be repeated. As the catalyst is repeatedly reused, insoluble matter containing copper cyanide as a main component is precipitated from the reaction solution, and the conversion rate of raw materials and the selectivity of the product are both reduced.

This deterioration can be suppressed by adding hydrohalic acid to the used catalyst. Examples of the hydrohalic acid include hydrochloric acid and hydrobromic acid,
These can be used in any of an aqueous solution, a gaseous state and a state of being dissolved in an organic solvent. The amount of hydrohalic acid used is about 0.01 to 0.1 with respect to 1 mol of the cuprous halide used.
It is a mole.

The hydrohalic acid may be added to the reaction solution after completion of the reaction, or the product may be added to the used catalyst after separation. Further, it may be added to the insoluble matter generated by the deterioration of the catalyst. Hydrohalic acid may be added to the catalyst solution before or after removing water.

In this reaction, a monocyano compound is also produced, which is further converted into a dicyano compound. Therefore, it is also possible to use a monocyano compound as a starting material.

[0015]

INDUSTRIAL APPLICABILITY According to the method of the present invention, 1,4-dicyano-2-butene can be obtained in good yield, high reaction rate and good volume efficiency. Further, the post-treatment is easy and the facility can be simplified. Further, the catalyst can be recycled and used, and the amount of the catalyst used can be reduced.

[0016]

EXAMPLES The present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. The purity indicates the content of 1,4-dicyano-2-butene in the crude product, and the yield indicates the value in terms of purity.

Example 1 15 g (0.15 mol) cuprous chloride and 15 g (0.15 mol)
6 mol) of trimethylamine hydrochloride was heated to 80 ° C. with stirring to prepare a catalyst melt. 22 g (0.25 mol) of 2-butene-1,4-diol and 20 ml (0.
A mixture of 5 mol) of hydrogen cyanide in 80 parts of the above catalyst solution.
The mixture was added dropwise at 3 ° C over 3 hours. After further holding at 80 ° C. for 3 hours, the contents of the flask were extracted 3 times with 50 ml of ethyl acetate at 30 to 40 ° C. Then, the solvent was evaporated under reduced pressure to concentrate 26 g of crude 1,4-dicyano-2-butene.
(Yield 86%, purity 88%) was obtained.

Example 2 5.0 g (0.05 mol) of cuprous chloride and 4.8 g
(0.05 mol) of trimethylamine hydrochloride with stirring,
It heated at 80 degreeC and prepared the catalyst melt. 8.8g
(0.1 mol) 3-butene-1,2-diol and 7.
A mixture of 6 ml (0.2 mol) of hydrogen cyanide was added dropwise to the above catalyst solution at 80 ° C. over 4 hours. 80 ° C
After holding at room temperature for 2 hours, the contents of the flask are heated at 30-40 ° C.
Then, it was extracted three times with 30 ml of ethyl acetate. The solvent was then evaporated under reduced pressure to give crude 1,4-dicyano-2.
-Butene 10.2 g (yield 78%, purity 81%) was obtained. Analysis by gas chromatography revealed that the other isomers were almost absent.

Example 3 9.9 g (0.1 mol) of cuprous chloride and 13.8 g
(0.1 mol) of triethylamine hydrochloride under stirring
It heated at 0 degreeC and prepared the catalyst melt. 17.6g
(0.2 mol) 2-butene-1,4-diol and 1
A mixture of 5.2 ml (0.2 mol) of hydrogen cyanide was added dropwise to the above catalyst solution at 80 ° C. over 4 hours. 8 more
After holding at 0 ° C. for 2 hours, the content of the flask was 30-40.
It was extracted twice with 30 ml of ethyl acetate at ° C. The solvent was then evaporated under reduced pressure to give crude 1,4-dicyano-
26 g of 2-butene (yield 70%, purity 57%) was obtained.

Example 4 9.9 g (0.1 mol) of cuprous chloride and 13.8 g
1 instead of (0.1 mol) triethylamine hydrochloride
4.3 g (0.1 mol) cuprous bromide and 9.6 g (0.
The same procedure as in Example 3 was performed except that 1 mol of trimethylamine hydrochloride was used. The result is crude 1,4-dicyano-2-
20.3 g of butene (yield 68%, purity 71%) was obtained.

Example 5 99 g (1.0 mol) of cuprous chloride, 96 g (1.0 mol) of trimethylamine hydrochloride and 0.2 g of copper powder were heated to 80 ° C. with stirring to melt the catalyst. Was prepared. 88 g
(1.0 mol) of 2-butene-1,4-diol and 76
A mixture of ml (2.0 mol) of hydrogen cyanide was added dropwise to the above catalyst solution at 80 ° C. over 4 hours. After further holding at 80 ° C for 2 hours, the content of the flask was kept at 70-80 ° C.
It was extracted 5 times with 100 ml of toluene. Then, the solvent was evaporated under reduced pressure to obtain crude 1,4-dicyano-2-butene. After the extraction operation, the catalyst liquid is recovered and 70 to 80 ° C.
Water was removed under reduced pressure at and was recycled for the next reaction. The reaction results are shown in Table 1. Extraction with toluene is not sufficient, and the yield does not always show a high value as compared with other examples.

[0022]

[Table 1]

Example 6 The catalyst solution was recovered, and water was removed under reduced pressure at 70 to 80 ° C.
Instead of recycling for the next reaction, collect the catalyst solution, add 2 g (0.02 mol) of concentrated hydrochloric acid at 70 to 80 ° C. and hold for 30 minutes, then remove water under reduced pressure for the next reaction. The same procedure as in Example 5 was carried out except that the material was recycled.
The results are shown in Table 2.

[0024]

[Table 2]

Comparative Example 1 15 g (0.15 mol) cuprous chloride and 15 g (0.15 mol)
6 mol) of trimethylamine hydrochloride was heated to 80 ° C. with stirring to prepare a catalyst melt. 43 g (0.25 mol) of 1,4-diacetoxy-2-butene and 20 ml
A mixture of (0.5 mol) of hydrogen cyanide was added dropwise to the above catalyst solution at 80 ° C. over 3 hours, and the mixture was kept at 80 ° C. for 1 hour. As a result of analysis by gas chromatography, the progress of the reaction was slow, so 10 ml of hydrogen cyanide was added after heating to 100 ° C. After holding at 100 ° C. for a further 4 hours, the flask contents were washed with ethyl acetate at 30-40 ° C.
Extract 3 times with ml. Then, the solvent was evaporated under reduced pressure to obtain 28 g of crude 1,4-dicyano-2-butene (yield 83%, purity 78%). Analysis by gas chromatography revealed that the raw material and the monocyanated product remained.

Claims (5)

[Claims] 1. 2-Butene-in the presence of a catalyst comprising cuprous halide and a non-aromatic organic amine halogenate.
1,4-diol and / or 3-butene-1,2-
A method for producing 1,4-dicyano-2-butene, which comprises reacting a diol and hydrogen cyanide. 2. The method for producing 1,4-dicyano-2-butene according to claim 1, wherein the water containing the used catalyst is removed and then reused. 3. The used catalyst is reused after reacting with hydrohalic acid and then removing water contained therein, or after removing contained water and then reacting hydrohalic acid. The method for producing 1,4-dicyano-2-butene according to claim 1. 4. The method for producing 1,4-dicyano-2-butene according to claim 1, wherein the cuprous halide is cuprous chloride or cuprous bromide. 5. The method for producing 1,4-dicyano-2-butene according to claim 1, wherein the non-aromatic organic amine halogenate is a lower alkylamine hydrochloride or hydrobromide.