JP3272550B2 - Method for producing N, N'-dialkylethylenediamine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process 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 solution of N, N'-dialkylethylenediamine obtained from 1,2-dihalogenoethane and an alkylamine.

[0002] N, N'-dialkylethylenediamine is a compound useful as a raw material and 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. Description of the Related Art
-When N, N'-dialkylethylenediamine is obtained by the reaction of dihalogenoethane with an alkylamine, the hydrogen halide formed by the reaction forms a salt with the alkylamine, and the alkylamine used is relatively expensive because the alkylamine used is relatively expensive. It is indispensable from an industrial point of view to neutralize and recover using alkali metals.

[0004] 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, water produced by the neutralization, and an alkali metal halide (hereinafter, referred to as a mixture). Aqueous slurry liquid). However, N, N'-dialkylethylenediamine is not easily separated from water because of its physical properties such as boiling point with water and high solubility with water. No production method including a method for separation and purification is disclosed.

[0005] However, those skilled in the art are required to extract the aqueous slurry liquid using a solvent that is immiscible with water (hereinafter, abbreviated as "extraction method"), and to add benzene, ethyl acetate, isopropyl ether to the aqueous slurry liquid. Water is azeotropically separated by using the method described above, and N, N'-dialkylethylenediamine and an alkali metal halide are filtered and separated (hereinafter abbreviated as water azeotropic method), using a water-soluble solvent for the aqueous slurry liquid. after filtering off the alkali metal halide, fine
How to cut (hereinafter, abbreviated as SeiTomeho) or the like can be known. However, these methods also have many disadvantages. For example, in the case of the extraction method, a large amount of a solvent is used and the extraction efficiency is low, so that the steps are complicated. In the case of the water azeotropic method, a long time is required, and the apparatus using an alkali metal is used. Is concerned, and in the case of the rectification method , there are problems such as the necessity of a very high-stage distillation column.
Purity is not satisfactory.

[0006] Therefore, overcoming and improving these disadvantages are desired, and the present invention aims to provide a method for easily obtaining N, N'-dialkylethylenediamine in high quality and high yield. To realize an industrial production method of dialkylethylenediamine.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve these problems, and as a result, added a basic compound to an aqueous slurry liquid, and thereafter did not mix with water, and
Not azeotropic with N, N'-dialkylethylenediamine
It has been found that N, N'-dialkylethylenediamine can be produced very efficiently by extraction and distillation using a solvent , and the present invention has been completed. That is, the present invention
General formula (1)

[0008]

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

[0010]

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Wherein R is as defined above. When the N, N' -dialkylethylenediamine is taken out from the obtained reaction solution after the reaction with the alkylamine represented by the formula (1) , the reaction solution has a stoichiometric amount based on 1,2-dihalogenoethane.
Alkyl formed during the reaction by adding stoichiometric amount of basic compound
Neutralizes the hydrogen halide salt of the amine
Presence of form was 1.0 mol times or more of a basic compound with respect to sodium chloride, immiscible with water, and N, this is extracted with an extraction solvent which does not azeotrope with N'- dialkyl ethylenediamine <br/> And a method for producing N, N'-dialkylethylenediamine represented by the general formula (1).

The present invention comprises a step of first reacting 1,2-dihalogenoethane with an alkylamine to obtain a reaction solution of N, N'-dialkylethylenediamine (hereinafter abbreviated as an amination step), and then a step of obtaining the reaction solution. Adding a basic compound to the resulting reaction solution to neutralize the alkyl halide hydrohalide generated during the reaction (hereinafter, abbreviated as a neutralization step),
Further, a step of adding a basic compound and salting out the N, N'-dialkylethylenediamine (hereinafter abbreviated as a salting out step), and subsequently, a step of recovering the alkylamine and extracting it with a solvent (hereinafter abbreviated as an extracting step). Do).

The 1,2 used in the amination step of the present invention
-Dihalogenoethane is 1,2-dichloroethane,
Examples thereof include 1,2-dibromoethane, 1-bromo-2-chloroethane, and the like, and the use of 1,2-dichloroethane is most preferable in terms of economy and availability.

The alkylamine used in the amination step of the present invention is selected depending on the target compound.
When N′-dimethylethylenediamine is to be obtained, methylamine may be used.

The alkylamine to be used may be used in the form of a liquid or an aqueous solution, but the use of the liquid amine in a liquid form provides a higher yield of the target compound, a higher volumetric efficiency and a higher yield of the basic compound in the neutralization salting-out step. Taking into account the amount of
It is preferable to use it as a liquid.

The 1,2 used in the amination step of the present invention
The alkylamine to dihalogenoethane molar ratio is
Although the stoichiometry is twice, it is required to be four times or more because a hydrogen halide of an alkylamine is generated by the hydrogen halide generated during the reaction. However, when the molar ratio is small, N, N′-dialkylpiperazine, N, N ′,
Optimally, it is 10 to 15 times because it causes an increase in by-products such as N ″ -trialkyldiethylenetriamine.

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

As the basic compound used in the neutralization step of the present invention, hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and calcium hydroxide, and alkaline earth metals or carbonates and bicarbonates thereof. Salts, sulfites and bisulfites. Optimally, taking into account the type of basic compound used in the following salting-out step, which is inexpensive,
Sodium hydroxide is good. The amount used may be a stoichiometric amount based on 1,2-dihalogenoethane used in the amination step.

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

For example, when a saturated aqueous solution of sodium hydroxide is used, the amount thereof is 1.0 mol times or more, and preferably 1.8 to 2.2 mol times, relative to the salt produced in the neutralization step. . Incidentally, it is naturally industrially optimal to use the same kind of alkali metal in the neutralization and salting-out steps. In this case, for example, when using sodium hydroxide, the necessary amount in the neutralization step and the salting-out step The total amount with the necessary amount may be used at a time.

As the extraction solvent used in the extraction step of the present invention, a solvent which is immiscible with water and which does not azeotrope with N, N'-dialkylethylenediamine is selected. For example, benzene, cyclohexane, ethyl acetate, orthodichlorobenzene and the like can be exemplified, but benzene is preferably used from the viewpoint of ease of separation from the target substance and economy.

The amount of use is not particularly limited. For example, if it is used in an amount of 2 times or more the weight of N, N'-dialkylethylenediamine, it can be extracted almost quantitatively. Just do it.

Next, in order to carry out the purification method of the present invention, for example, a saturated sodium hydroxide aqueous solution is added to the reaction solution obtained by the amination reaction of reacting 1,2-dihalogenoethane with an alkylamine to recover the alkylamine. After that, the precipitated salt is separated by filtration, and the obtained filtrate is subjected to extraction using, for example, benzene, and the N, N′-dialkylethylenediamine is easily distilled at a high yield and high purity from the separated benzene layer by distillation. Can be obtained. The aqueous sodium hydroxide solution after the separation can be recycled by concentrating.

[0024]

The present invention will now be described by way of Examples and Comparative Examples.
This will be specifically described. The analysis was performed by gas chromatography. Example 1 In a 1-liter autoclave, 99.0 g (1 mol) of 1,2-dichloroethane and 372.7 g (1 mol) of methylamine were added.
2 mol), and the mixture was sealed, and then subjected to an amination reaction at 95 to 100 ° C for 2 hours. The pressure during this time is 18-20 kg /
cm ² G. After the reaction, the system was cooled to 50 ° C., and the system was cooled to room temperature while releasing and releasing the methylamine gas. As a result of analyzing the obtained reaction solution, 78.0% (68.8 g) of N, N′-dimethylethylenediamine, 3.2% (1.8 g) of N, N′-dimethylpiperazine, N, N ′, N ''
-Trimethyldiethylenetriamine 15.0% (10.
9g) yield (vs. charged 1,2-dichloroethane)
Met. This reaction solution was neutralized at room temperature, and 4
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 distill off methylamine. The reaction solution from which methylamine was distilled off had salt precipitated, and was filtered to separate the salt from the aqueous layer. 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, thereby separating the benzene layer and the 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 ratio of N, N'-dimethylethylenediamine (weight of N, N'-dimethylethylenediamine in extractant / weight of N, N'-dimethylethylenediamine in reaction solution × 100) was 99.5%. Subsequently, the benzene layer was subjected to distillation under normal pressure using a distillation column having 5 theoretical plates, and benzene was distilled off.
68.0 g of N, N′-dimethylethylenediamine was obtained as a fraction at 0 to 125 ° C. (during distillation, no precipitation of salt was observed in the still). It has a purity of 98.1% (N, N'-
Dimethylpiperazine 1.8%), yield 97.0%
(To N, N'-dimethylethylenediamine in the amination reaction solution).

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

Example 3 The same treatment as in Example 1 was carried out using the same reaction solution as in Example 1 except that the extractant was changed from benzene to orthodichlorobenzene. N, N'-dimethylethylenediamine obtained after distillation was 68.0 g, and the purity was 98.0%.
The yield was 96.9%.

Comparative Example 1 The amination reaction solution obtained in Example 1 was neutralized by adding 178.0 g of a 45% aqueous sodium hydroxide solution at room temperature.
The temperature was gradually raised to about 75 ° C. to distill off methylamine.
700.0 benzene was added to the reaction solution from which methylamine was distilled off.
g, and the mixture was extracted and separated 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 determined. The extraction ratio of N, N'-dimethylethylenediamine was 7.2%. Further, the aqueous layer was extracted with 500.0 g of benzene, and the extraction rate of N, N'-dimethylethylenediamine in the benzene layer obtained after liquid separation was 4.8%.

Comparative Example 2 700.0 g of chloroform was added to the same reaction solution from which methylamine was distilled off as in Comparative Example 1, and the mixture was extracted and separated to separate into 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 added to a distillation apparatus provided with a distillation column corresponding to five theoretical plates.
The same reaction solution from which methylamine was distilled off and 200.0 g of benzene were charged. A separation pipe for water and benzene was provided in the distilling section of the distillation column, and benzene was returned to the distillation still. Distillation of water and benzene was confirmed from around the top temperature of 68 ° C., starting with heating, and the operation of extracting water and returning benzene to the kettle was repeated. When the temperature at the top of the column 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 residue in the kettle was a slurry in which salt was precipitated, and most of the salt adhered to the wall of the kettle and solidified. 200.0 g of benzene was charged into the bottom of the kettle, and filtration was performed while scraping off the deposits to separate a benzene layer and salt. When the obtained benzene layer was analyzed, 59.9 g of N, N'-dimethylethylenediamine was quantified, which corresponds to 87.1% based on N, N'-dimethylethylenediamine in the reaction solution charged at the time of distillation. Quantity. or,
N, N'-dimethylethylenediamine was detected in the water extracted during the distillation. Example 1 continued with benzene layer
As a result of performing the same distillation as described 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 As in Comparative Example 1, 230.0 g of isopropyl alcohol was added to the reaction solution from which methylamine was distilled off , and the precipitated salt was filtered and separated. When the obtained isopropyl alcohol layer was analyzed, 68.5 g of N, N'-dimethylethylenediamine was quantified, which was N, N'-
This is an amount corresponding to 99.5% based on dialkylethylenediamine. Subsequently, the isopropyl alcohol layer was subjected to distillation under normal pressure using a distillation column having 25 theoretical plates to remove isopropyl alcohol and water.
A fraction at 125 ° C. and 65.3 g of N, N′-dimethylethylenediamine were obtained. It has a purity of 95.0% (isopropyl alcohol 1.2%, water 1.8%, N, N'-
Dimethylpiperazine 1.8%), yield 90.2%
Met.

[0031]

Industrial Applicability According to the present invention, N, N'-dialkylethylenediamine can be industrially produced with high yield and high purity. That is, Comparative Example 1 outside the scope of the present invention
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, loss to the outside of the system is caused, and in Comparative Example 4, it is extremely high. Both methods have drawbacks such as the necessity of a rectification column , and all of these methods are obviously disadvantageous in terms of yield and quality, and are industrially disadvantageous. On the other hand, in the present invention, as shown in Examples 1 to 3, by extracting and distilling with a solvent using a basic compound, N, N ′ having a higher purity than the comparative example was obtained.
It is clear that dialkylethylenediamine can be obtained easily and in high yield, and the significance of the present invention is great.

Continuation of the front page (56) References JP-A-60-4152 (JP, A) JP-A-58-213738 (JP, A) JP-A-47-39012 (JP, A) JP-A-2-145545 (JP) , A) JP-A-63-27460 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 209/84 C07C 209/08 C07C 211/10

Claims (3)

(57) [Claims] 1. A compound of the general formula (1) [Wherein, R represents an alkyl group having 1 or 2 carbon atoms. In producing the N, N'-dialkylethylenediamine represented by the general formula (1), 1,2-dihalogenoethane and the general formula (2) [Wherein, R is the same as defined above. After the reaction with the alkylamine represented by the formula (1), N, N'-
When taking out the dialkyl ethylenediamine, the reaction solution
Stoichiometric basicity to 1,2-dihalogenoethane
The halo of the alkylamine formed during the reaction by adding the compound
Neutralizes the hydrogen genide salt
Extraction is performed using an extraction solvent that is not miscible with water and does not azeotrope with N, N'-dialkylethylenediamine in the presence of a basic compound in an amount of 1.0 mol times or more. )), A method for producing N, N′-dialkylethylenediamine. 2. An N, N'-dialkyl immiscible with water.
Extraction solvent that does not azeotrope with ethylenediamine
, Cyclohexane, ethyl acetate or orthodichlorobe
The method of claim 1, wherein the method is selected from senzen. 3. The compound represented by the general formula (1) is N,
3. The composition according to claim 1, which is N'-dimethylethylenediamine.
The described method.