JPH0892173A - Production of n,n-dialkylethylenediamine - Google Patents

Abstract

PURPOSE: To isolate the high-quality compound useful as a raw material or an intermediate for medicines and industrial chemicals in a high yield by extracting a reacted liquid of a dihalogenoethane with an alkylamine in the presence of a basic compound using an extracting solvent. CONSTITUTION: This method for producing N,N'-dialkylethylenediamine (preferably N,N'-dimethylethylenediamine) of the formula is to react (A) a 1,2- dihalogenoethane (especially preferably 1,2-dichloroethane) with (B) an alkyldiamine (preferably a liquid) of the formula R-NH2 (R is a 1-2C alkyl)and carry out salting out and extraction of the resultant reacted liquid using (D) an extracting solvent (a solvent which is immiscible with water and does not make azeotropic mixture with the product, preferably benzene) in the presence of (C) a basic compound (especially preferably a saturated aqueous solution of sodium hydroxide).

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for producing N, N'-dialkylethylenediamine. For more information,
The present invention relates to a production method for efficiently isolating N, N'-dialkylethylenediamine from a reaction liquid of N, N'-dialkylethylenediamine obtained from 1,2-dihalogenoethane and alkylamine.

N, N'-dialkylethylenediamine is a compound useful as a raw material and an intermediate for pharmaceuticals and industrial chemicals. In particular, N, N'-dimethylethylenediamine is a very important compound as an intermediate of 1,3-dimethyl-2-imidazolidinone which is an aprotic polar solvent.

[0003]

2. Prior Art and Problems to be Solved by the Invention
-When N, N'-dialkylethylenediamine is obtained by the reaction of dihalogenoethane and an alkylamine, the hydrogen halide formed by the reaction forms a salt with the alkylamine, and the alkylamine used is relatively expensive, so the alkylamine salt It is indispensable from an industrial standpoint to neutralize and recover using alkali metals.

The reaction solution obtained by neutralizing the reaction solution and recovering the alkylamine by the above method is mainly a mixture of N, N'-dialkylethylenediamine and water and an alkali metal halide produced by the neutralization (hereinafter, It is abbreviated as an aqueous slurry liquid). However, N, N′-dialkylethylenediamine has a similar boiling point to water and is not easily separated from water because of its physical properties such as high solubility with water, and it is industrially efficient and simple. A manufacturing method including a method of separating and purifying is not disclosed.

However, those skilled in the art can extract the aqueous slurry using a solvent immiscible with water (hereinafter abbreviated as extraction method), and use benzene, ethyl acetate, isopropyl ether for the aqueous slurry. A method in which water is azeotropically separated using, for example, N, N'-dialkylethylenediamine and an alkali metal halide are filtered and separated (hereinafter, abbreviated as water azeotropic method), and a water-soluble solvent is used in an aqueous slurry liquid. It is possible to know a method for scouring after filtering out the alkali metal halide (hereinafter abbreviated as scouring method) and the like. However, these methods also have many drawbacks, for example, in the case of the extraction method, a large amount of solvent is required and the extraction efficiency is small, so the process becomes complicated, and in the case of the water azeotropic method, it takes a long time and the apparatus using an alkali metal is used. There is a concern that the corrosiveness of the, further, in the case of the purification method, such a problem that a very high-stage distillation column is required, and the yield of any method,
Purity is not what you want.

Therefore, it is desired to overcome and improve these drawbacks, and the present invention aims at a method of easily obtaining N, N'-dialkylethylenediamine in high quality and in high yield. It realizes an industrial production method of dialkylethylenediamine.

[0007]

Means for Solving the Problems As a result of intensive studies to solve these problems, the present inventors have added a basic compound to an aqueous slurry solution, and then extracted with a solvent,
It was found that N, N'-dialkylethylenediamine can be produced very efficiently by distillation, and the present invention has been completed. That is, the present invention relates to the general formula (1)

[0008]

[Chemical 3]

[In the formula, R represents an alkyl group having 1 or 2 carbon atoms. ] In producing the N, N'-dialkylethylenediamine represented by the formula 1,2-dihalogenoethane and the general formula (2)

[0010]

[Chemical 4]

[In the formula, R is the same as the above definition. ] When an N, N'-dialkylethylenediamine is taken out from the obtained reaction solution after reacting with an alkylamine represented by the formula, a general formula characterized by using an extraction solvent in the presence of a basic compound ( The present invention provides a method for producing N, N′-dialkylethylenediamine represented by 1).

The present invention comprises a step of first reacting 1,2-dihalogenoethane with an alkylamine to obtain a reaction liquid of N, N'-dialkylethylenediamine (hereinafter abbreviated as an amination step), and then obtained. A step of adding a basic compound to the reaction solution to neutralize the alkylamine hydrogen halide salt formed during the reaction (hereinafter, abbreviated as a neutralization step),
A step of further adding a basic compound to salt out N, N′-dialkylethylenediamine (hereinafter abbreviated as salting out step), a step of subsequently recovering alkylamine and extracting with a solvent (hereinafter abbreviated as extraction step) It consists of).

1,2 used in the amination step of the present invention
-Dihalogenoethane is 1,2-dichloroethane,
1,2-Dibromoethane, 1-bromo-2-chloroethane and the like can be mentioned, and the use of 1,2-dichloroethane is most preferable from the viewpoint of economical efficiency and availability.

The alkylamine used in the amination step of the present invention is selected according to the target compound, and for example, N,
Methylamine may be used when N'-dimethylethylenediamine is to be obtained.

The alkylamine used may be used as a liquid or as an aqueous solution, but the yield of the target compound is higher when it is used as a liquid, and the volume efficiency and the basic compound in the neutralization salting-out step are used. When considering the amount of addition of
It is preferably used as a liquid.

1,2 used in the amination process of the present invention
-The molar ratio of alkylamine to dihalogenoethane is
The stoichiometry is twice, but it is necessary to be four times or more because the hydrogen halide generated during the reaction produces a hydrogen halide salt of alkylamine. However, when the molar ratio is small, N, N'-dialkylpiperazine, N, N ',
Since it causes an increase in by-products such as N ″ -trialkyldiethylenetriamine, it is optimally 10 to 15 times.

The reaction temperature in the amination step of the present invention is not particularly limited, but is 0 to 200 ° C., and most preferably 80.
~ 120 ° C.

The basic compound used in the neutralization step of the present invention includes alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and calcium hydroxide, and alkaline earth metal hydroxides or their carbonates and bicarbonates. Examples thereof include salts, sulfites and bisulfites. Optimally cheap and considering the type of basic compound used in the next salting out step,
Sodium hydroxide is good. The amount used may be stoichiometric with respect to the 1,2-dihalogenoethane used in the amination step.

As the basic compound used in the salting-out step of the present invention, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferable, and sodium hydroxide is most preferable from the economical viewpoint. These may be used in the form of an aqueous solution or a solid, but in view of operability, economy, the effect of extracting the target substance in the extraction step, and the like, it is most preferable to use a saturated aqueous solution.

When a saturated aqueous sodium hydroxide solution is used, the amount used is 1.0 mol times or more, and most preferably 1.8 to 2.2 mol times, the salt produced in the neutralization step. . Industrially, of course, it is optimal to use the same type of alkali metal in the neutralization and salting-out process. In that case, for example, when sodium hydroxide is used, the necessary amount in the neutralization process and The total amount with the required amount may be used at one time.

As the extraction solvent used in the extraction step of the present invention, a solvent that is immiscible with water and does not azeotrope with N, N'-dialkylethylenediamine is selected. For example, benzene, cyclohexane, ethyl acetate, ortho-dichlorobenzene and the like can be exemplified, but the use of benzene is preferable from the viewpoint of separability from the target product and economical efficiency.

The amount used is not particularly limited. For example, if it is used in an amount of 2 times by weight or more the amount of N, N'-dialkylethylenediamine, the amount is almost quantitatively extracted. If an amount less than this is used, extraction is performed several times. I'll do it.

Next, in order to carry out the purification method of the present invention, for example, saturated sodium hydroxide aqueous solution is added to the reaction solution obtained by the amination reaction in which 1,2-dihalogenoethane and alkylamine are reacted to recover the alkylamine. After that, the precipitated salt is separated by filtration, the obtained filtrate is extracted with, for example, benzene, and the separated benzene layer is easily distilled by distillation to give a high yield and high purity of N, N′-dialkylethylenediamine. Can be obtained. Further, the sodium hydroxide aqueous solution after liquid separation can be recycled for reuse by concentrating.

[0024]

EXAMPLES Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.
This will be specifically described. The analysis was performed by gas chromatography. Example 1 Into a 1-liter autoclave, 92.0 g (1 mol) of 1,2-dichloroethane and 372.7 g (1
(2 mol) was charged and sealed, and then an amination reaction was carried out at 95 to 100 ° C. for 2 hours. The pressure during this period is 18 to 20 kg /
cm ² G was shown. After the reaction, the temperature was cooled to 50 ° C., and the temperature was cooled to room temperature while releasing and releasing methylamine gas. As a result of analyzing the obtained reaction liquid, N, N'-dimethylethylenediamine 78.0% (68.8 g), N, N'-dimethylpiperazine 3.2% (1.8 g), N, N ', N ''
-Trimethyldiethylenetriamine 15.0% (10.
9 g) yield (vs. charged 1,2-dichloroethane)
Met. Neutralize this reaction solution at room temperature and use 4 as a salting-out agent.
355.6 g (4 mol) of a 5% aqueous sodium hydroxide solution was added, and the temperature was gradually raised to about 75 ° C. to remove methylamine. Salt was deposited in the reaction liquid from which methylamine was removed, and the salt was separated from the aqueous layer by filtration. further,
140.0 g of benzene as an extractant was charged into the obtained aqueous layer, and the mixture was extracted and allowed to stand to separate into a benzene layer and an aqueous layer.
When the benzene layer was analyzed, 68.5 g of N, N′-dimethylethylenediamine, 1.8 g of N, N′-dimethylpiperazine, and 10.8 g of N, N ′, N ″ -trimethyldiethylenetriamine were quantified. The extraction rate of N, N′-dimethylethylenediamine (N, N′-dimethylethylenediamine weight in extractant / N, N′-dimethylethylenediamine weight in reaction liquid × 100) was 99.5%. Subsequently, the benzene layer is distilled under atmospheric pressure using a distillation column having 5 theoretical plates, and after removing benzene, the column top temperature is 12
A small amount of 0 to 125 ° C. and 68.0 g of N, N′-dimethylethylenediamine were obtained (precipitation of salt is not observed in the distillation pot during distillation). This product has a purity of 98.1% (N, N'-
(Containing 1.8% of dimethylpiperazine), yield 97.0%
(N, N′-dimethylethylenediamine in the amination reaction liquid).

Example 2 The same reaction solution as in Example 1 was used, except that the basic compound at the time of neutralization and salting out was changed from a 45% aqueous sodium hydroxide solution to a 45% aqueous potassium hydroxide solution. The same process was performed. The N, N′-dimethylethylenediamine obtained after the distillation was 68.2 g, and the purity was 98.0% and the yield was 9
It was 7.2%.

Example 3 The same treatment as in Example 1 was carried out using the same reaction liquid as in Example 1 except that benzene was changed to ortho-dichlorobenzene as the extracting agent. The N, N′-dimethylethylenediamine obtained after the distillation was 68.0 g, and the purity was 98.0%,
The yield was 96.9%.

Comparative Example 1 178.0 g of a 45% aqueous sodium hydroxide solution was added to the amination reaction solution obtained in Example 1 at room temperature to neutralize it.
The temperature was gradually raised to about 75 ° C. to remove methylamine.
Benzene 700.0 is added to the reaction solution from which methylamine has been removed.
g was added for extraction and liquid separation to separate into a benzene layer and an aqueous layer. When the benzene layer was analyzed, 5.0 g of N, N′-dimethylethylenediamine, 0.1 g of N, N′-dimethylpiperazine, and 0.8 g of N, N ′, N ″ -trimethyldiethylenetriamine were quantified. The extraction rate of N, N′-dimethylethylenediamine was 7.2%. Further, the water layer was extracted with 500.0 g of benzene, and after the liquid separation, the N, N′-dimethylethylenediamine extraction rate in the obtained benzene layer was 4.8%.

Comparative Example 2 700.0 g of chloroform was added to the reaction solution obtained by removing methylamine as in Comparative Example 1 for extraction and liquid separation to separate a chloroform layer and an aqueous layer. N in the chloroform layer,
The N′-dimethylethylenediamine extraction rate was 27.5%.

Comparative Example 3 Comparative Example 1 was used in a still equipped with a distillation column corresponding to 5 theoretical plates.
The same reaction solution as described above in which methylamine was removed and 200.0 g of benzene were charged. A separation pipe for water and benzene was installed in the distillation section of the distillation column, and benzene was returned to the distillation pot. Distillation of water and benzene was confirmed from around the column top temperature of 68 ° C. starting from heating, water was extracted, and benzene was returned to the kettle. When the tower top temperature was around 80 ° C., the distillation of water stopped and the heating was stopped. It took about 12 hours from the start of heating to the stop. The residual liquid in the kettle was in the form of a slurry in which salt was deposited, and most of the salt adhered to the vessel wall of the kettle and solidified. 200.0 g of benzene was charged into this residual liquid in the kettle, and filtration was performed while scraping off the deposits to separate the benzene layer and salt. When the obtained benzene layer is analyzed, 59.9 g of N, N′-dimethylethylenediamine is quantified, which corresponds to 87.1% based on N, N′-dimethylethylenediamine in the reaction solution charged at the time of distillation. Is the amount. or,
N, N'-dimethylethylenediamine was detected in the water extracted during the distillation. Subsequently, the benzene layer was used in Example 1.
As a result of performing the same distillation as above, the obtained N, N′-dimethylethylenediamine was 59.5 g, and the purity was 98.0.
%, And the yield was 84.8%.

Comparative Example 4 230.0 g of isopropyl alcohol was added to the same reaction solution as in Comparative Example 1 in which methylamine was removed, and the precipitated salt was separated by filtration. When the obtained isopropyl alcohol layer was analyzed, 68.5 g of N, N'-dimethylethylenediamine was quantified, which was N, N'- in the reaction solution.
This is an amount corresponding to 99.5% based on the dialkylethylenediamine. Subsequently, the isopropyl alcohol layer is distilled under atmospheric pressure using a distillation column having a theoretical plate number of 25, and after removing isopropyl alcohol and water, the column top temperature is 120 to
A small amount of 125 ° C. and 65.3 g of N, N′-dimethylethylenediamine were obtained. This product has a purity of 95.0% (isopropyl alcohol 1.2%, water content 1.8%, N, N'-
(Containing 1.8% of dimethylpiperazine), yield 90.2%
Met.

[0031]

Industrial Applicability According to the present invention, it is possible to industrially produce N, N'-dialkylethylenediamine with high yield and high purity. That is, Comparative Example 1 outside the scope of the present invention
In No. 2 and 2, the extraction efficiency is low and a large amount of solvent is required, in Comparative Example 3, the operability is deteriorated due to solidification of the alkali metal chloride, and loss to the outside of the system is caused, and in Comparative Example 4, it is very high There is a drawback such as the need for a rectification column in stages, and any method is an industrially disadvantageous production method because the yield and quality are obviously deteriorated. On the other hand, according to the present invention, as shown in Examples 1 to 3, by extracting and distilling a basic compound with a solvent, a higher purity N, N 'than the comparative example is obtained.
-It is clear that dialkylethylenediamine can be easily obtained in a high yield, and the significance of the present invention is great.

Front page continuation (72) Inventor Teruyuki Nagata 30 Asamu-cho, Omuta-shi, Fukuoka Mitsui Toatsu Chemical Co., Ltd.

Claims (2)

[Claims] 1. A compound represented by the general formula (1): [In the formula, R represents an alkyl group having 1 or 2 carbon atoms. ] In producing the N, N'-dialkylethylenediamine represented by the formula, 1,2-dihalogenoethane and a compound represented by the general formula (2): [In the formula, R is the same as the above definition. ] After reacting with an alkylamine represented by the formula, N, N'-
A method for producing N, N′-dialkylethylenediamine represented by the general formula (1), wherein an extracting solvent is used in the presence of a basic compound when the dialkylethylenediamine is taken out. 2. A compound represented by the general formula (1) is N,
The method according to claim 1, which is N'-dimethylethylenediamine.