JP2012241011A - Production method of 1,3-dimethyl-2-imidazolidinone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a method by which 1,3-dimethyl-2-imidazolidinone (denoted by DMI hereinafter) can be continuously produced by an easy means.SOLUTION: In the method, N,N-dimethylethylenediamine (denoted by DED hereinafter) is made to react with urea by using DMI as a solvent. Specifically, a raw material mixture comprising DED and urea is gradually added to a reaction vessel 1 to which DMI as a solvent is preliminarily introduced, to carry out the reaction and to allow the solution to overflow; the overflow solution is introduced to a reaction vessel 2 to fill the vessel, followed by stopping introduction of the overflow solution to complete the reaction; the overflow solution from the reaction vessel 1 is then introduced to another reaction vessel 3 and subjected to the same process as in the reaction vessel 2; the overflow solution from the first reaction vessel 1 is introduced to a newly replaced reaction vessel 2; and these processes are successively repeated to continue the reaction.

Description

  The present invention relates to a method for producing 1,3-dimethyl-2-imidazolidinone (hereinafter referred to as DMI), and more specifically, to provide a simple method and a method capable of continuously producing DMI. .

  DMI is a very useful substance that is widely used as a polar aprotic solvent. In particular, it is an excellent solvent for polymer compounds such as polyamides, polyvinyl chloride, polyvinyl alcohol, polystyrene, polyurethane, phenol resin, etc. Also, it forms complex salts with many inorganic salts and dissolves, and it is capable of many organic reactions. It is a useful substance that can also be used as a solvent.

  Conventionally, many manufacturing methods of DMI have been proposed. For example, a method of reacting N, N′-dimethylethylenediamine and carbon dioxide (Patent Document 1) or a reaction product obtained by reacting ethylenediamine and urea to obtain 2-imidazolidinone and adding formalin thereto. Reduction with trichloroacetic acid, formic acid, etc. to N, N'-dimethylation, improvement of this reduction method using a noble metal catalyst, hydrogenation under acidic conditions, and further from N, N'-dimethylethylenediamine A method of reacting phosgene or trichloromethyl chloroformate while decomposing it into phosgene is known.

Furthermore, Patent Document 2 focuses on the fact that 1,1′-dimethyl-1,1′-dimethylenebisurea is produced as an intermediate when N, N′-dimethylethylenediamine and urea are reacted by heating. In the presence of a polar aprotic solvent, about 2 moles of urea is added to N, N'-dimethylethylenediamine to complete the formation of 1,1'-dimethyl-1,1'-dimethylenebisurea in the initial reaction. Until now, a two-step method characterized by reacting at 140 ° C. or lower and subsequently adding N, N′-dimethylethylenediamine at 180 ° C. or higher has been proposed.
JP 1-15505 No. 6-65666

Problems to be solved by the invention

As described above, various methods for producing DMI are conventionally known. However, the yield is extremely low by any of the methods, and the industrial method is not completely satisfactory.
Therefore, the problem to be solved by the present invention is to provide a method capable of continuously producing industrially useful DMI by a simple method.

Means for solving the problem

This problem of the present invention is solved by producing DMI by reacting N, N'-dimethylethylenediamine (hereinafter referred to as DED) with urea using DMI as a solvent. The raw material mixture consisting of DED and urea is gradually added to the introduced reaction vessel 1 to cause the overflow while reacting, and this overflow solution is introduced into the reaction vessel 2 and filled, and then the overflow solution is introduced. Is terminated to complete the reaction, and the overflow liquid from the reaction vessel 1 is introduced and transferred to the other reaction vessel 3, and thereafter the same treatment as the reaction vessel 2 is performed, and the reaction vessel 1 is replaced with the newly replaced reaction vessel 2. This is preferably achieved by introducing an overflow liquid from and continuously repeating the process.

Effect of the invention

As described above, the present invention is characterized by the use of the target product DMI as a solvent in the reaction of DED and urea, and this is a new method which has never been performed in the past. By adopting this method, it is possible to obtain an excellent effect that the reaction can be continued easily and continuously.
As a result, the target product DMI can be easily produced at an extremely high yield, and can be used as an industrially excellent production method.

The present invention is characterized by reacting DED with urea using DMI as a reaction solvent. This can be expressed in chemical formula as follows:

  In this reaction, the raw materials DED and urea are added to DMI, and the mixture is heated usually at 180 to 230 ° C., preferably about 200 to 220 ° C. for about 3 to 5 hours. The ratio of DED to urea may be 1: 1, but one may be excessive. The DMI used as a solvent is usually about 1 to 5 times that of DED. The DED used as one of the raw materials can be produced by, for example, an ordinary method from ethylenediamine and iodomethane.

  Another major feature of the present invention is that this reaction can be carried out continuously by using DMI as a solvent. This continuous method will be described below with reference to the drawings.

The reaction vessel 2 is connected to the cock 4 of the reaction kettle 1, and the cock 5 is connected to the reaction kettle 3 having the same capacity. The reaction kettles 2 and 3 are each equipped with a stirring motor, a cooling pipe, a thermocouple, and a dropping funnel. A stirrer motor, cooling pipe, and thermocouple are attached to.
Next, the reaction kettle 1 with the cocks 4 and 5 closed is filled with DMI, put in an oil bath, and the temperature inside the kettle is maintained at a predetermined temperature. Each of the reaction kettles 2 and 3 is filled with DMI and similarly put in an oil bath, and the temperature inside the kettle is maintained at a predetermined temperature.

  On the other hand, a predetermined amount of DED, urea, and solvent DMI are mixed as a raw material mixture, and heated with stirring to liquefy the whole.

  This raw material mixture is put into a dropping funnel attached to the reaction kettle 1 and dropped into the reaction kettle 1, and the reaction of DED and urea in the raw material mixture is started using DMI in the reaction kettle 1 as a solvent. At the same time, the level of the reaction liquid in the reaction vessel 1 rises, and when the liquid level rises and reaches the cock portion, the cock 4 is opened. The reaction liquid overflows from the cock 4 and is dropped toward the reaction kettle 2. If the raw material mixture is continuously dropped into the reaction kettle 1 at the same speed, the dropping into the reaction kettle 2 is also continued, and the reaction proceeds in the reaction kettles 1 and 2.

  When the reaction liquid in the reaction vessel 2 reaches a predetermined amount, the cock 4 is closed and at the same time the cock 5 is opened. The reaction liquid in the reaction vessel 1 overflows from the cock 5 and is dropped to the reaction vessel 3 this time. If the raw material mixture is continuously dropped into the reaction vessel 1 at the same speed, the addition to the reaction vessel 3 is also continued, and the reaction proceeds in the reaction vessels 1 and 3.

  The reactor 2 with the cock 4 closed is kept heated and stirred as it is for a predetermined time, and then the heating is stopped, the reaction kettle 2 is removed from the cock 4 and distilled as it is to remove the remaining colored components and high-boiling substances. To obtain high purity DMI.

  The same cock as the reaction kettle 2 described above is newly connected to the cock 4 from which the reaction kettle 2 has been removed.

  On the other hand, when the reaction liquid in the reaction kettle 3 reaches a predetermined amount, the cock 5 is closed, and at the same time, the cock 4 is opened, and the reaction liquid in the reaction kettle 1 overflows from the cock 1 and is newly attached. Drip toward the pot 2. If the raw material mixture is continuously dropped into the reaction vessel 1 at the same speed, the addition to the reaction vessel 2 is also continued, and the reaction proceeds in the reaction vessels 1 and 2.

  The reactor 3 with the cock 2 closed is kept heated and stirred for a predetermined time, and then the heating is stopped, the reaction kettle 3 is removed from the cock 5 and distilled in a slightly reduced pressure state as it is. High boilers are removed to obtain high purity DMI. The same cock as the reaction kettle 2 described above is newly connected to the cock 2 from which the reaction kettle 3 has been removed.

The raw material mixture dropped into the reaction kettle 1 is made at any time by the same method as described above, and added to the dropping device as necessary.
By repeating this operation, high-purity DMI can be synthesized continuously.
Hereinafter, the present invention will be described in detail with reference to examples.

A stirring motor, a condenser tube, a thermocouple, and a dropping funnel were attached to the reaction kettle 1 having a capacity of 0.5 L. A reaction kettle 2 with a capacity of 0.5 L is connected to the cock 4 of the reaction kettle 1, and a reaction kettle 3 with a capacity of 0.5 L is also connected to the cock 5, and a stirring motor, a cooling pipe and a thermocouple are attached to each reaction kettle. It was. Next, 0.5 L of DMI (1,3-dimethyl-2-imidazolidinone, Neos) is charged in the reaction kettle 1 with the cocks 4 and 5 closed, and the temperature inside the kettle is adjusted to 210 to 220 ° C. Maintained. The reaction kettles 2 and 3 were each filled with 0.15 L of DMI, put in the oil bath, and the temperature inside the kettle was maintained at 210-220 ° C.

  As a raw material mixture, 100 g of DED, 72 g of urea (special grade, Kanto Chemical) and 100 g of DMI as a solvent were mixed and heated to 90 ° C. with stirring to liquefy the whole. This raw material mixture was put into a dropping funnel attached to the reaction kettle 1 and dripping into the reaction kettle 1 was started.

  The raw material mixture was added dropwise at a rate of about 50 g per hour. Using DMI in the reaction vessel 1 as a solvent, DED and urea in the raw material mixture started to react, and at the same time, the liquid level of the reaction solution in the reaction vessel 1 rose. When the liquid level rose and reached the cock part, the cock 1 was opened. The reaction liquid overflowed from the cock 1 and dropped into the reaction kettle 2. When the raw material mixture was continuously added dropwise to the reaction vessel 1 at the same speed, the addition to the reaction vessel 2 was also continued, and the reaction proceeded in the reaction vessels 1 and 2.

  When the reaction liquid in the reaction vessel 2 reached about 0.5 L, the cock 1 was closed and the cock 2 was opened at the same time. The reaction liquid in the reaction vessel 1 overflowed from the cock 2 and was dropped to the reaction vessel 3 this time. When the raw material mixture was continuously dropped into the reaction kettle 1 at the same speed, the dropping into the reaction kettle 3 was continued, and the reaction proceeded in the reaction kettles 1 and 3.

  The reactor 2 with the cock 1 closed was continuously heated and stirred for about 4 hours. Stop the heating, remove the reaction kettle 2 from the cock 1, and distill at 120-150 ° C. in a slightly reduced pressure state to remove the remaining colored components and high-boiling substances, resulting in a high purity of 99.8% DMI was obtained with a yield of 99% based on the raw material. The same thing as the reaction kettle 2 demonstrated previously was newly connected to the cock 1 which removed the reaction kettle 2. FIG.

  On the other hand, when the reaction liquid in the reaction kettle 3 reached about 0.5 L, the cock 2 was closed and at the same time the cock 1 was opened. The reaction liquid in the reaction vessel 1 overflowed from the cock 1 this time and dropped onto the newly attached reaction vessel 2. When the raw material mixture was continuously added dropwise to the reaction vessel 1 at the same speed, the addition to the reaction vessel 2 was also continued, and the reaction proceeded in the reaction vessels 1 and 2.

  The reactor 3 with the cock 2 closed was heated and stirred for about 4 hours. Heating is stopped, the reaction kettle 3 is removed from the cock 2 and distilled as it is at 120 to 150 ° C. in a slightly reduced pressure state to remove the remaining colored components and high-boiling substances, thereby obtaining a high purity of 99.8%. DMI was obtained with a yield of 99% based on the raw material. The same cock as the reaction kettle 3 described above was newly connected to the cock 2 from which the reaction kettle 3 was removed.

The raw material mixture dropped into the reaction kettle 1 was made at any time by the same method as described above, and added to the dropping device as needed.
By repeating this operation, it was possible to continuously synthesize DMI having a purity of 99.8%.

In a 500 ml four-necked flask equipped with a thermometer, a stirrer, and a reflux tube, 100 g of ethylenediamine (manufactured by Tokyo Chemical Industry, special grade), 101 g of urea (manufactured by Kanto Chemical Co., Ltd., special grade), and ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) , Special grade) 108g. ]
The temperature was raised while stirring, and when the temperature of the reaction solution reached about 130 ° C., stirring was stopped and refluxed for 4 hours. The reaction solution was further raised to about 210 ° C., and ethylene glycol was removed while gradually reducing pressure to obtain 2-imidazolidinone (90 g) as an intermediate product.

Subsequently, 75 g of paraformaldehyde (manufactured by Kanto Chemical Co., Ltd., special grade) and 480 g of formic acid (manufactured by Kanto Chemical Co., Ltd., special grade) are added to the obtained intermediate product, and the reaction solution temperature is 115 ° C. while stirring. The reaction was continued for 16 hours. As it was, it was discharged from the top of the reflux tube and subjected to atmospheric distillation to distill off unreacted paraformaldehyde and carbon dioxide. Subsequently, distillation was performed under reduced pressure at a pressure of 39 to 67 hPa and a temperature of 120 to 134 ° C., and unreacted formic acid and water were distilled off to obtain 60 g of crude DMI having a purity of about 90%.

By-products having a structure similar to DMI contained in the crude DMI were removed by filtration. Subsequently, the formic acid remaining in the crude DMI was distilled off under reduced pressure at a pressure of 22.6 hPa and a temperature of 105 ° C. to obtain 54 g of 1,3-dimethyl-2-imidazolidinone as the final product.
When the obtained product was measured using GC-FID (gas chromatography hydrogen flame ionization detector), the purity was 99% or more.
This reaction can be represented by the chemical formula as follows.

  FIG. 1 is a schematic explanatory diagram for explaining an embodiment of the present invention.

1: Reaction kettle 2: Same as above 3; Same as above 4: Cook 5: Same as above

Claims (3)

  A process for producing 1,3-dimethyl-2-imidazolidinone, comprising reacting N, N-dimethylethylenediamine and urea using 1,3-dimethyl-2-imidazolidinone as a solvent   Overflow while conducting a reaction by gradually adding a raw material mixture consisting of N, N-dimethylethylenediamine and urea to a reaction vessel 1 in which 1,3-dimethyl-2-imidazolidinone as a solvent was previously introduced. After the overflow liquid is introduced into the reaction kettle 2 and filled, the introduction of the overflow liquid is stopped to complete the reaction, and the overflow liquid from the reaction kettle 1 is introduced into the other reaction kettle 3, 2. The process according to claim 1, wherein the same treatment as in the reaction kettle 2 is performed thereafter, and the overflow liquid from the reaction kettle 1 is introduced into the newly replaced reaction kettle 2 and this is sequentially repeated continuously.     The production method according to claim 1 or 2, wherein the N, N-dimethylethylenediamine used is produced by a reaction of ethylenediamine and iodomethane.

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