JPH10101651A - Highly pure 1,3-dialkyl-2-imidazolidinone and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound having extremely high purity and extremely low content of by-products originated from raw materials in high yield by reacting an N,N'-dialkylethylenediamine with urea. SOLUTION: This compound is a compound of the formula III obtained by the reaction of an N,N'-dialkylethylenediamine of the formula I (R is an alkyl) with urea and containing <0.1wt.% of by-produced 1,3-dialkyl-2- imidazolidine imine of the formula II. The objective compound can be produced by reacting the compound of the formula I with urea while adding both compounds to an aprotic polar solvent. The reaction is continuously carried out at 200-260 deg.C by using the objective 1,3-dialkyl-2-imidazolidinone as the reaction solvent while adding the raw materials at a rate to attain a residence time of 5-10hr. The process is preferably applied to the production of 1,3- dimethyl-2-imidazolidinone from N,N'-dimethylethylenediamine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to 1,3-dialkyl-2-imidazolidinones and a method for producing the same. More specifically, the present invention relates to a 1,3-dialkyl-2-imidazolidinone having a very low content of by-products obtained by a reaction between N, N'-dialkylethylenediamine and urea, and a method for producing the same. 1,3-Dialkyl-2-imidazolidinone is a highly polar aprotic solvent, is extremely stable to acids and alkalis as compared with general aprotic polar solvents, and has various inorganic and organic properties. Since it has a strong dissolving power for compounds, it is a very useful substance as a synthetic solvent for medicines, agricultural chemicals, dyes, pigments, etc., a cleaning agent for electronic parts, molds, etc., a polymerization solvent for polymer compounds, and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for producing 1,3-dialkyl-2-imidazolidinone, a method for producing 1,3-dialkyl-2-imidazolidinone from N, N'-dialkylethylenediamine and urea is known. Although this method is an excellent method as a simple process, the conventionally known method has a drawback that the yield is low. Thereafter, this disadvantage was remedied and the N, N′-dialkylethylenediamine and urea were heated at a temperature of 180 ° C. or higher, preferably the intermediate 1,1′-dimethyl-1,1.
The 1'-dimethylenebisurea is completed at a temperature of 140 ° C., and
A method for producing 1,3-dialkyl-2-imidazolidinone in a yield of more than 1% is known (US Pat. No. 4,731,45).
3). However, according to this method, 1,3-dimethyl-2
It contains 0.5% to several% by-produced 1,3-dimethyl-2-imidazolidinimine with respect to imidazolidinone, the by-product having a boiling point of 1,3-dimethyl-2-imidazolidinone. Due to the similarity, there was a problem in the removal of by-products, such as the necessity of a very high column for distillation separation and the necessity of a separate treatment step. In addition, 1,3-dimethyl-2-imidazolidinone containing this by-product as described above inhibits a desired reaction when used as a solvent. For example, when used as a solvent for producing aramid, polymerization of a polymer is inhibited. This causes a problem, and there is a drawback in its application.

[0003]

However, using N, N'-dialkylethylenediamine and urea as raw materials, 1,3
The method for directly producing -dialkyl-2-imidazolidinone has advantages over conventionally known methods, such as the use of inexpensive raw materials and the necessity of separation of generated water, and the like. This is an excellent method for industrially producing 3-dialkyl-2-imidazolidinone. Therefore,
There has been a strong demand for a production method that does not produce this by-product in this method.

[0004]

The present inventors have proposed N, N '.
The present inventors have intensively studied a method for producing 1,3-dialkyl-2-imidazolidinone directly from dialkylethylenediamine and urea in high yield and high purity. As a result, N,
The above-mentioned problem has been solved by employing a method in which N′-dialkylethylenediamine and urea are reacted under specific raw material addition conditions, that is, while simultaneously and continuously dropping into a heated aprotic polar solvent. Found that 1,3-dialkyl-2-imidazolidinone can be produced very efficiently, with high yield, and with extremely high purity,
The present invention has been completed.

That is, the present invention provides a compound represented by the following general formula (1):

Embedded image (In the formula, R represents an alkyl group.)
-Obtained by reacting dialkylethylenediamine with urea, and having the formula (3)

Embedded image (Wherein, R represents an alkyl group.)
General formula (2) in which the content of 3-dialkyl-2-imidazolidinimine is less than 0.1% by weight,

Embedded image Wherein R is the same as defined above, and 1,3-dialkyl-2-imidazolidinone represented by the formula:
The method is characterized in that a dialkyl-2-imidazolidinone is reacted while continuously adding an N, N′-dialkylethylenediamine represented by the general formula (1) and urea to an aprotic polar solvent. A method for producing a 1,3-dialkyl-2-imidazolidinone represented by the general formula (2),

In this method, the N, N'-dialkylethylenediamine and urea are added at a rate of a residence time of 5 hours or more. Reacting while continuously adding dialkylethylenediamine and urea,
The reaction product is continuously withdrawn. The aprotic polar solvent is 1,3-dialkyl-2-imidazolidinone, which is a product. In the general formulas (1) and (2), R represents 1 carbon atom. It is preferably an alkyl group of 4 to 4.

According to the present invention, 1,3-dialkyl-2-
Also in the method of reacting N, N'-dialkylethylenediamine and urea, which is an industrial production method of imidazolidinone, the content of by-product 1,3-dialkyl-2-imidazolidinimine is less than 0.1% by weight. It has become possible to provide 1,3-dialkyl-2-imidazolidinone represented by a general formula (2). The method of the present invention is a method for industrially producing 1,3-dialkyl-2-imidazolidinone with extremely high efficiency and high yield and extremely high purity, and the method of the present invention is carried out under normal pressure. However, the fact that the reaction is carried out is a great advantage in terms of equipment, and the continuous operation enables more stable operation on an industrial scale, and the present invention is significant.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The 1,3-dialkyl-2-imidazolidinone represented by the general formula (1) of the present invention has the general formula
R in (1) is an alkyl group and has 1 to 8 carbon atoms, particularly 1 to 4 carbon atoms, specifically 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2 -Imidazolidinone, 1,3-dipropyl-2-imidazolidinone, 1,3-dibutyl-2-imidazolidinone and the like, in particular 1,3-dimethyl-2-imidazolidinone is a useful compound. It is frequently used for solvents, solvents and the like. These 1,3-dialkyl-2-imidazolidinones of the present invention are obtained by reacting N, N′-dialkylethylenediamine represented by the general formula (2) with urea. In the reaction of these raw materials, the by-product of 1,3-dialkyl-2-imidazolidinimine represented by the formula (3) is inevitable. In the conventionally known method, it was at least about 0.5% by weight based on the product 1,3-dialkyl-2-imidazolidinone.

The 1,3-formula represented by the general formula (1) of the present invention
Dialkyl-2-imidazolidinone is a by-product of this, 1,
The content of 3-dialkyl-2-imidazolidinimine is undetectable by chromatographic analysis,
That is, 0.1% by weight of the detection limit of 1,3-dialkyl-2-imidazolidinimine by chromatography.
Therefore, the content of this by-product is less than 0.1% by weight.

The high purity 1,3-dialkyl-2 of the present invention
-The characteristics of the method for producing imidazolidinone in high yield include:
The reaction is to be carried out while continuously adding 1,3-dialkyl-2-imidazolidinone represented by the general formula (1) and urea to an aprotic polar solvent.

The N, N'-dialkylethylenediamine represented by the general formula (1) used in the method of the present invention includes:
N, N′-dimethylethylenediamine, N, N′-diethylethylenediamine, N, N′-dipropylethylenediamine, N, N′-diisopropylethylenediamine, wherein R is an alkyl group of 1 to 8 in the general formula (1) , N'-dibutylethylenediamine, N, N'-
Dipentylethylenediamine, N, N'-dihexylethylenediamine, N, N'-diheptylethylenediamine, N, N'-dioctylethylenediamine and the like, preferably N, N'-dimethylethylenediamine, N, N'-diethylethylenediamine, N, N '
-Dipropylethylenediamine, N, N'-diisopropylethylenediamine and N, N'-dibutylethylenediamine, more preferably N, N'-dimethylethylenediamine. Among these, N, N'- corresponding to the desired 1,3-dialkyl-2-imidazolidinone
Dialkylethylenediamine is appropriately selected and used.

These N, N'-dialkylethylenediamines can be easily obtained by reacting a corresponding monoalkylamine with an ethylene dihalide such as ethylene dichloride or ethylene bromide.

The solvent used in the method of the present invention is an aprotic polar solvent. Protonic solvents such as water, alcohols and 2-oxoimidazolidines and low-polar aprotic solvents such as hydrocarbons and halogenated hydrocarbons are not preferred because the desired effects cannot be sufficiently obtained. However, these solvents may be mixed and used with an aprotic polar solvent within a range not to impair the effects of the present invention, for the purpose and reaction operation. The aprotic polar solvent used in the method of the present invention is preferably N-methyl-2-pyrrolidone, N, N '.
-Dimethylformamide, N, N'-dimethylacetamide, tetramethylurea, dimethylsulfoxide, hexamethylphosphoramide, sulfolane, dioxane, and 1,3-dimethyl-2-imidazolidinone, 1,3
1,3-dialkyl-2-imidazolidinone such as diethyl-2-imidazolidinone and 1,3-dipropyl-2-imidazolidinone. In the method of the present invention,
Preferably, the reaction is carried out at a temperature of 180 ° C. or higher. If the solvent used has a low boiling point, an excessive facility is required. Therefore, a solvent having a boiling point of 180 ° C. or higher is preferable. Optimally, 1,3-dialkyl-2-imidazolidinone produced by the reaction from is used as a self-solvent.

In the method of the present invention, the reaction temperature is preferably at least 180 ° C., particularly preferably from 200 to 2 ° C.
60 ° C. At 180 ° C. or higher, the reaction rate is high and 1,1′-dialkyl-1,1′-dimethylenebisurea as an intermediate is prevented from remaining, and the yield is improved. It is also preferable from the viewpoint of suppressing by-products of impurities such as 1,3-dialkyl-2-imidazolidinimine. Considering an industrial heating method, the temperature is preferably 260 ° C. or lower.

In the method of the present invention, the reaction is carried out while N, N'-dialkylethylenediamine and urea are continuously added to the aprotic polar solvent heated to the above reaction temperature. Conventionally, in the reaction between N, N'-dialkylethylenediamine and urea, the initial reaction is carried out at a low reaction temperature, and the reaction for producing 1,1'-dialkyl-1,1'-dimethylenebisurea as an intermediate product is performed. After completion, it was said that 1,3-dialkyl-2-imidazolidinimine could be produced in high yield by successively raising the temperature to 180 ° C. or higher to carry out a ring closure reaction. The by-product of dialkyl-2-imidazolidinimine could not be sufficiently suppressed. By reacting N, N'-dialkylethylenediamine and urea continuously in an aprotic polar solvent heated to a temperature of 180 ° C. or higher as in the present invention, high yields and by-products are obtained. 1,3-dialkyl-2
It was completely unpredictable that high-purity 1,3-dialkyl-2-imidazolidinimine having an imidazolidine imine content of less than 0.1 wt% would be obtained.

In the method of the present invention, N, N 'to be added
The amount ratio of dialkylethylenediamine to urea is usually
It is selected in a molar ratio of 1.0: 0.5 to 1.0: 2.0.
In order to reduce by-products derived from N, N'-dialkylethylenediurea, to suppress the remaining N, N'-dialkylethylenediamine and to prevent a decrease in yield, the following 1.0:
A molar ratio in the range of 1.0 to 1.0: 1.2 is optimal.

The method of continuously adding N, N'-dialkylethylenediamine and urea in the method of the present invention includes a method of adding a slurry liquid in which both are mixed in advance, a method of adding both separately, and a method of adding each separately. Urea is dissolved by heating in an aprotic polar solvent and N, N '
There is no particular limitation on the method of adding each of -dialkylethylenediamine and each other, but N, N'-
It is necessary to continuously add dialkylethylenediamine and urea so that they are immediately reacted in an aprotic polar solvent. The term “continuous” includes the case where the addition is performed intermittently at a predetermined addition rate for a predetermined time as necessary, or the case where the addition is continuously performed while changing the addition rate.

In the method of the present invention, the rate of addition of N, N'-dialkylethylenediamine and urea required for the reaction in the aprotic polar solvent is as follows:
It is appropriately selected depending on the type of N, N'-dialkylethylenediamine and the reaction temperature, and is not particularly limited, but is preferably a rate at which substitution can be performed in 5 hours or more with respect to the amount of the aprotic polar solvent used. (Residence time 5 hours or more). Particularly preferred is a residence time of 5
10 hours. For example, when 100 parts by weight of an aprotic polar solvent is used in the production of 1,3-dimethyl-2-imidazolidinone, a mixture of N, N′-dimethylethylenediamine and urea becomes aprotic polar solvent 1
The rate at which 00 parts by weight can be replaced in 5 hours or more,
It may be added at a rate of 20 parts by weight / hour or less (residence time 5 hours or more). When added at a rate of less than 5 hours residence time, 1,1'-dimethyl-1,1'-dimethylenebisurea remains, and the yield of 1,3-dialkyl-2-imidazolidinone tends to decrease. .

It is preferable to take care not to substantially contain water in the N, N'-dialkylethylenediamine, urea and 1,3-dialkyl-2-imidazolidinone used in the present invention. Performing the reaction in a water-free system requires decomposition of urea during the reaction, and furthermore, N, N'-
It prevents dialkylethylenediamine from distilling out of the reaction system and the like to prevent a reduction in reaction yield. The temperature in the reactor is usually kept constant. This reaction can be carried out under normal pressure or under pressure. Usually, it is carried out at normal pressure.

Further, stable operation can be achieved by continuously extracting the reaction product. As a typical embodiment in this case, an aprotic polar solvent is heated in a reactor equipped with an inlet pipe for N, N'-dialkylethylenediamine and urea, and a pipe for extracting a reaction product. , N′-Dialkylethylenediamine and urea are reacted while being continuously added to form 1,3
-Dialkyl-2-imidazolidinone is withdrawn from the withdrawal tube, and the 1,3-dialkyl-2- is continuously used for a long time.
There is a method for producing imidazolidinone. The reaction can be carried out in a batch system or a continuous system, but a continuous system is desirable from the viewpoint of productivity and stable operation. 1,3-dialkyl-2 can be easily obtained from the obtained reaction product by an operation such as distillation.
The imidazolidinone can be removed;

[0021]

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. When the purity of 1,3-dialkyl-2-imidazolidinone produced by the reaction of N, N'-dialkylethylenediamine and urea was analyzed by this analysis method, when the purity of 1,3-dimethyl-2-imidazolidin as a by-product was determined. The detection limit of imine is 0.1 wt%. In the following Examples and Comparative Examples, gas chromatography analysis was performed using the following equipment. Equipment: Shimazu GC-9A (manufactured by Shimadzu Corporation) Column: 10% Uconoil 50HB 5100 + 5% NaOH CromoSorb W
AW DMCS (GL Science) φ3m / m x 3m glass Column temperature: 135 ° C Detector: FID Data processing: Shimazu R6A (Shimadzu)

Example 1 An extraction tube was provided from the bottom of a flask, connected to a pump, and a device for introducing a discharge portion of the pump into a 1-liter reactor was prepared. In the flask, N, N'-dimethylethylenediamine and urea were mixed at a weight ratio of 57:43 and stirred. 100 g of 1,3-dimethyl-2-imidazolidinone (hereinafter, abbreviated as DMI) was charged into a 1 liter reactor, the internal temperature was maintained at 220 ° C. while stirring, and N, N′-dimethylethylenediamine was added from a pump. A mixture of urea was added into the reactor at a rate of 20 g / H. The addition was performed for 30 hours, during which the temperature inside the reactor was kept at 215 to 220 ° C. After the completion of the addition, the temperature was maintained at the same temperature, and the stirring was continued for another 2 hours, and then cooled to room temperature. The amount of the obtained reaction solution was 542 g, the purity of DMI was 98.2 wt%,
3-dimethyl-2-imidazolidinimine was not detected. The yield of DMI determined by subtracting the amount of DMI initially charged in the reactor was 97.6% based on N, N'-dimethylethylenediamine added. Subsequently, the reaction solution was distilled using a distillation column equivalent to five stages to obtain DMI506 having a purity of 99.9% (1,3-dimethyl-2-imidazolidinimine was not detected (less than 0.1%)).
g was obtained. The chart of gas chromatography is shown in FIG. As is clear from this figure, 1,3-dimethyl-2-
No imidazolidine imine could be detected.

Example 2 An extraction tube was provided from the bottom of a flask, connected to a pump, and a device for introducing a discharge portion of the pump into a 1-liter reactor was prepared. An extraction pipe, a cooling pipe, and a receiver were provided in the body of the reactor. 600ml content up to the withdrawal part of the reactor
It is. 600 g of DMI was charged into the reactor, the internal temperature was kept at 220 ° C. while stirring, and a mixture of N, N′-dimethylethylenediamine and urea adjusted at the same mixing ratio as in Example 1 was pumped at a rate of 100 g / H. Into the reactor. The addition was carried out for 24 hours, during which the temperature inside the reactor was kept at 215 to 220 ° C., and the reaction product was stored in a receiver. After the addition and cooling, the amount in the reactor was 586.
g, the purity of DMI is 98.1 wt%, and the amount in the receiver is 17
The purity of 92 g and DMI was 98.3 wt%. The yield of DMI in the reactor and the receiver was 2337 g, and D was determined by subtracting the amount of DMI initially charged in the reactor.
The yield of MI was 97.7% based on N, N'-dimethylethylenediamine added. Also, 1,3-dimethyl-2-imidazolidinimine was not detected in the reaction solution and the receiver. The detection limit of chromatography is 0.
It was 1% and had a DMI exceeding 99.9 wt% in purity. Subsequently, the liquid in the receiver was distilled using a distillation column equivalent to five stages to obtain a purity exceeding 99.9 wt% (1,3-
DMI of dimethyl-2-imidazolidinimine not detected)
1691 g were obtained.

Example 3 A reactor was charged with 570 g of 1,3-dipropyl-2-imidazolidinone (hereinafter abbreviated as DPI) and 1372 g of N, N'-dipropylethylenediamine and 628 g of urea in a flask. To the reactor at a rate of 7
The same reaction as in Example 1 was performed except that the amount was 0 g / H.
The DPI yield determined by the same method as in Example 1 was 97.
2%. Also, 1,3-dipropyl-2-imidazolidinimine was not detected in the reaction solution and the receiver.
The detection limit of the chromatography was 0.1%, and the purity was 99.9% by weight.

Example 4 600 g of N-methyl-2-pyrrolidone in a reactor and N, N'-dibutylethylenediamine 2045 in a flask
g and urea 856 g, and the same reaction as in Example 1 was performed except that the rate of addition to the reactor was 120 g / H and the temperature in the reactor was 200 to 210 ° C. The yield of 1,3-dibutyl-2-imidazolidinone obtained in the same manner as in Example 1 was 96.5%. Also, 1,3-dibutyl-2-imidazolidinimine was not detected in the reaction solution and the receiver. DMI over 99.9 wt% purity
Met.

Example 5 In the flask used in Example 1, 1140 g of urea and DM
I2660 g was charged and urea was dissolved at 100 ° C. under stirring and kept as it was. Prepare a new flask and pump and add 1500 g of N, N'-dimethylethylenediamine
Was charged. The reactor used in Example 1 contained DMI60
0 g was charged, the internal temperature was maintained at 220 ° C. while stirring, and the mixture of urea and DMI was continuously pumped at 150 g / H.
And N, N'-dimethylethylenediamine was added into the reactor at a rate of 60 g / H. The method of calculating the addition time, reaction temperature, and yield was the same as in Example 1.
The yield of DMI was 98.0%. Also, 1,3-dimethyl-2-imidazolidinimine was not detected in the reaction solution and the receiver.

Comparative Example 1 A 500 ml autoclave was charged with N, N'-dimethylethylenediamine (88 g), urea (66 g) and DMI (100 g). The temperature was raised to a reaction temperature of 210 ° C. in about 30 minutes, and the reaction was carried out at that temperature for 3 hours. Maximum system pressure is about 15kg / cm ² G
Reached. After the reaction was completed, the reaction mixture was cooled and the contents were taken out to obtain a slurry containing white crystals. The filtrate was filtered to obtain a filtrate having a weight of 200.1 g and a DMI purity of 97.
3 wt%. The DMI yield determined by subtracting the amount of DMI initially charged in the autoclave was 81.0% based on the charged N, N'-dimethylethylenediamine.
%Met. In addition, 1,3-dimethyl-
0.8% by weight of 2-imidazolidine imine was detected.
The chart of gas chromatography is shown in FIG. Subsequently, the filtrate was distilled under the same conditions as in Example 1. As a result, 188 g of DMI having a purity of 99.2 wt% was obtained, in which 1,3-dimethyl-2-imidazolidinimine had 0.1%.
7 wt% was detected.

Comparative Example 2 A 500 ml autoclave charged in the same manner as in Comparative Example 1 was reacted at a reaction temperature of 120 ° C. for 8 hours. After the start of the reaction, the pressure in the system gradually increased and became almost constant at about 6 kg / cm ² G. Subsequently, the temperature was raised to 210 ° C. in about 30 minutes, and the reaction was carried out at that temperature for 3 hours. The system pressure reached up to about 15 kg / cm ² G. The yield of DMI determined by the same method as in Comparative Example 1 was 96.5%, and 1,3-dimethyl-2 was contained in the filtrate.
1.0% by weight of imidazolidine imine was detected.

Comparative Example 3 N, N'-dimethylethylenediamine 44 was placed in a 300 ml flask equipped with a reflux condenser, a dropping funnel and a stirrer.
g, urea 66 g, and DMI 100 g were charged at 120 ° C.
And reacted for 2 hours. Subsequently, while the temperature was raised to 210 ° C., 44 g of N, N′-dimethylethylenediamine was charged into the dropping funnel, and this was dropped from around 200 ° C. over about 2 hours. Thereafter, the reaction was further carried out for about 1 hour while maintaining at 215 to 220 ° C. The yield of DMI determined by the same method as in Comparative Example 1 was 97.0%, and the filtrate contained 0.5% of 1,3-dimethyl-2-imidazolidinimine.
wt% was detected. That is, in Comparative Examples 1 and 2, which are outside the scope of the present invention, 1,3-dialkyl-2-imidazolidinimine having a boiling point close to that of 1,3-dialkyl-2-imidazolidinone was produced. In contrast, according to the present invention, as shown in Examples 1 to 5, 1,3-dialkyl-2
-High-purity 1,3-dialkyl-2-imidazolidinone could be obtained easily, efficiently and in high yield without producing imidazolidine imine.

[0030]

Industrial Applicability According to the present invention, industrial production of 1,3-dialkyl-2-imidazolidinone with extremely high efficiency and high yield has become possible. Further, the fact that the reaction is carried out even under normal pressure is a great advantage in terms of equipment. Further, the continuous type enables more stable operation on an industrial scale, and the present invention is significant.

[Brief description of the drawings]

FIG. 1 shows the 1,3-dialkyl-2- obtained in Example 1.
3 shows a chart of gas chromatography of imidazolidinone.

FIG. 2 shows 1,3-dialkyl-2- obtained in Comparative Example 1.
3 shows a chart of gas chromatography of imidazolidinone.

Claims (9)

[Claims] 1. A compound represented by the general formula (1): (In the formula, R represents an alkyl group.)
-Obtained by the reaction of dialkylethylenediamine with urea and having the formula (3) (Wherein, R represents an alkyl group.)
General formula (2) wherein the content of 3-dialkyl-2-imidazolidinimine is less than 0.1 wt% (Wherein R is the same as defined above), 1,3-dialkyl-2-imidazolidinone. 2. The 1,3-dialkyl-2 according to claim 1, wherein R in the general formula (2) is an alkyl group having 1 to 4 carbon atoms.
-Imidazolidinone. 3. A compound represented by the general formula (1): (In the formula, R represents an alkyl group.)
-Reacting a dialkylethylenediamine with urea in an aprotic polar solvent; (Wherein, R is the same as defined above.) In a method for producing 1,3-dialkyl-2-imidazolidinone, N, N′-dialkylethylenediamine and urea are mixed in an aprotic polar solvent. A method for producing 1,3-dialkyl-2-imidazolidinone represented by the general formula (2), wherein the reaction is carried out while continuously adding. 4. The compound represented by the general formula (1) or (2)
Is an alkyl group having 1 to 4 carbon atoms, and the method for producing 1,3-dialkyl-2-imidazolidinone according to claim 3. 5. The 1,3-dialkyl-2-solvent according to claim 3, wherein the aprotic polar solvent is heated to 180 ° C. or higher.
A method for producing imidazolidinone. 6. The method for producing 1,3-dialkyl-2-imidazolidinone according to claim 3, wherein the aprotic polar solvent is 1,3-dialkyl-2-imidazolidinone. 7. The method for producing 1,3-dialkyl-2-imidazolidinone according to claim 3, wherein the addition of the N, N′-dialkylethylenediamine and urea is performed at a rate at which the residence time is 5 hours or more. 8. The reaction carried out while continuously adding 18
The method for producing 1,3-dialkyl-2-imidazolidinone according to claim 3, which is carried out at a temperature of 0 ° C or higher. 9. The method for producing 1,3-dialkyl-2-imidazolidinone according to claim 3, wherein the reaction product is continuously extracted from the reaction system.