JPH07103109B2 - Method for producing 2-imidazolidinones - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides compounds of formula (I) (In the formula, R is a lower alkyl group. R ¹ , R ² , R ³ and R
⁴ is a hydrogen atom or a lower alkyl group, at least one of which is a lower alkyl group. ) By the reaction of the diamine represented by
I) (Wherein, R, R ^1, R ^2, R ³ and R ^4, R, the same. As R ^1, R ^2, R ³ and R ⁴ of formula (I)) 2-imidazolidinone represented by To a method of manufacturing.

The 2-imidazolidinones represented by the above formula (II) are useful substances as aprotic polar solvents and intermediates for pharmaceuticals and agricultural chemicals. In particular, it is an excellent solvent for high molecular compounds such as polyamides, polyvinyl chloride, polyvinyl alcohol, polystyrene, polyurethane, and phenolic resins, and also easily dissolves many inorganic compounds and is used as a solvent for various characteristic organic reactions. To be

[Conventional technology]

Several methods for producing 2-imidazolidinones represented by the above formula (II) have been proposed. For example, with respect to 1,3,4-trimethyl-2-imidazolidinone, a method of reacting N, N'-dimethyl-1,2-propanediamine and urea to obtain a yield of 75% [Liebitzhis anarene deachemy ( Liebig. Ann. Der Chem.), 726, 97 (19
69)], 1,3,4-trimethyl-4-imidazoline-2-
Method for hydrogenating on-on [Riebitzhis anarene
Die Chemie (Liebig. Ann. Der Chem.), Vol. 726, page 97 (1969)], a method of reacting N, N'-dimethyl-1,2 propanediamine with diethylcarbamyl chloride [US Patent No. 2398283 (1943). )] Etc. are known.

[Problems to be solved by the invention]

As described above, a method for obtaining 2-imidazolidinones from diamines and urea is known, but in order to improve the operability of the reaction mass and the yield, 1.5 mol of diamines is used per 1 mol of urea. And use it excessively.

Excess diamines are expensive and must be recovered from the reaction mass. The yield was 75%, which was not yet satisfactory as an industrial production method.

The present invention provides an industrial process for reacting a diamine represented by the above formula (I) with a urea to obtain a 2-imidazolidinone represented by the above formula (II) in good yield. .

[Means for solving problems]

MEANS TO SOLVE THE PROBLEM The inventors of the present invention react the diamines represented by the above formula (I) with urea to obtain the 2-imidazolidinones represented by the above formula (II) at low cost, high yield, and operability. Earnestly studied a good industrial manufacturing method, and obtained the following knowledge, and thus achieved the present invention.

(1). Usually, in the reaction between diamines and urea, 2-
Before the formation of the imidazolidinones, the diamine urea intermediate is formed. In many cases, this intermediate has low solubility in a nonpolar solvent and precipitates out of the system. But,
The ring-closure reaction to 2-imidazolidinone is extremely slow unless this intermediate is 180 ° C. or higher in the dissolved state. For this reason
Under polar aprotic solvent with high solubility of urea intermediate,
It was found that when the diamines and urea were reacted at 180 ° C. or lower, 2-imidazolidinones were obtained in high yield.

(2). Furthermore, in the reaction of diamines with urea in a polar aprotic solvent, when the urea intermediate of diamines is produced, the reaction is performed at 140 ° C or lower, and then at 180 ° C or higher, the yield is further increased. I found a thing.

In the reaction of diamines with urea in a polar aprotic solvent, the initial reaction until the urea intermediate is formed is particularly 180
Temperatures above ℃ are not required. The reaction is slower at 100 ° C or lower, but the reaction proceeds sufficiently from around 100 ° C to 140 ° C or lower. Above 180 ℃, urea loss occurs due to thermal decomposition of urea itself. Therefore, it was found that the two-step rising reaction method allows urea to be used for the reaction more efficiently.

The end point of the reaction from the diamine to the urea intermediate is easily judged by the end of ammonia generation. In this two-step temperature raising method, since diamines and urea are used without waste,
It is not necessary to use the diamines and the urea in excess, and the molar ratio of the diamines / urea charged may be 0.6 to 1.2. It is preferable to charge so that the molar ratio is almost equimolar. If excess diamines are charged, an operation to recover expensive diamines will be added.If excess urea is charged, solid impurities such as cyanuric acid, which is a thermal decomposition product of urea, will remain in the reaction system, resulting in complicated solid-liquid separation. Operations have been added, but these issues have been resolved.

(3). Further, the present inventors have further studied as an industrial production method and found the following invention.

When the above two-step temperature raising method is adopted, the initial reaction at 140 ° C or lower is not a problem, but in most cases the boiling point of diamines is 180 ° C.
Since it is below, when the reaction is carried out at a temperature of 180 ° C or higher, it is difficult to react at 180 ° C or higher under normal pressure because unreacted diamines remain. Must. In order to avoid this, the present inventors charged the diamines / urea in a molar ratio of about 1/2 in the presence of a polar aprotic solvent at the beginning of the reaction to complete the formation of the urea intermediate in the initial reaction. Up to 140 ° C, and then at 180 ° C or higher, by adding diamines so that the total molar ratio of diamines / urea becomes about 2/2,
It has been found that 2-imidazolidinones can be obtained in high yield even at atmospheric pressure.

The reason for this is that urea is added to the diamine in an amount of about 2 times the mole of the diamine at the beginning of the reaction, and the urea intermediate produced in the initial reaction is almost completely a non-volatile diurea compound of the diamine. This is because the raw material diamines do not remain, and it is possible to raise the temperature by 180 ° C. or more even at normal pressure. Therefore, according to this method, the boiling point of the solvent is 180 ℃
If it is above, the reaction can be performed under normal pressure throughout the reaction. It was also found that the diamines added at 180 ° C. or higher are effectively subjected to the reaction, and the yield is not inferior to the method in which the two-step temperature rising method is used for batch charging.

As the solvent used in the method of the present invention, nonpolar solvents such as hydrocarbons and halogenated hydrocarbons are not suitable, and polar aprotic solvents are used. Preferred solvents include N, N'-dimethylformamide, N, N'-dimethylacetamide, tetramethylurea, dimethylsulfoxide, hexamethylphosphoramide, sulfolane, methyl isobutyl ketone, nitrobenzene, tetrahydrofuran, dioxane, and the like aproton. A polar solvent can be used. Further, when the boiling point is low, an excessive pressure resistance device is required. Therefore, a solvent having a boiling point of 180 ° C. or higher is preferable.
-Imidazolidinones are the best.

The raw material diamines represented by the above formula (I) used in the present invention are N, N'-dimethyl-1,2-propanediamine, N,
Examples include N ', 2-trimethyl-2,3-butanediamine and N, N'-diethyl-1,2-propanediamine.

The 2-imidazolidinones represented by the above formula (II) obtained in the present invention are the corresponding 2-imidazolidinones obtained by using the above diamines, and are 1,3,4-trimethyl-2. -Imidazolidinone, 1,3,4,4,5-pentamethyl-2-imidazolidinone, 1,3, -diethyl-4-methyl-2-imidazolidinone and the like.

To describe a preferred ordinary embodiment of the method of the present invention, in the case of pressurization, in an autoclave equipped with a thermometer and mechanical stirring, raw material diamines, urea, polar aprotic solvent is charged, after the reaction at 140 ° C. or less in advance, Reheat to 180 ° C or higher to react. In the method of adding diamines at atmospheric pressure, in a reactor equipped with a reflux condenser, a thermometer, a dropping funnel and a mechanical stirrer, diamines, urea, polar aprotic solvent are charged, and ammonia at 140 ° C or lower is added. The reaction is carried out until the generation is completed, and then the temperature is raised to 180 ° C. or higher and the reaction is carried out while adding diamines from a dropping funnel. 2-Imidazolidinones can be taken out from the reaction completed liquid by distillation or the like. Especially when 2-imidazolidinones formed are used as a solvent, it is not necessary to separate the solvent from the solvent during distillation,
It is a very simplified process.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 In a 500 ml stainless steel autoclave, 102.2 g (1.00 mol) of N, N'-dimethyl-1,2-propanediamine, 60.1 g (1.00 mol) of urea and 1,3,4-trimethyl-2-imidazolidi Non-100g was charged. Increase the reaction temperature to 120
The reaction was carried out at 8 ° C for 8 hours. Continue to raise the temperature to 210 ℃,
The reaction was carried out for 3 hours.

After completion of the reaction, 1,3,4-trimethyl-2-imidazolidinone was quantified by gas chromatography. 1,3,4-
The yield of trimethyl-2-imidazolidinone is 94.9%.
Met.

Example 2 Instead of the raw material N, N'-dimethyl-1,2-propanediamine, 130.3 g of N, N ', 2-trimethyl-2,3-butanediamine
(1.00 mol), except that 1,3,4,4,5-pentamethyl-2-imidazolidinone 100 g was used as the solvent instead of 1,3,4-trimethyl-2-imidazolidinone. Reaction and analysis were carried out in the same manner as in Example 1. As a result, 1,3,4,4,
The yield of 5-pentamethyl-2-imidazolidinone is 9
It was 3.3%.

Examples 3 to 6 Reactions and analyzes were performed in the same manner as in Example 1 except that 100 g of various solvents shown in Table 1 were used instead of the solvent 1,3,4-trimethyl-2-imidazolidinone. 1,3,4 in each solvent
-Production yield of trimethyl-2-imidazolidinone is shown in Table 1.
It was shown to.

Example 7 Equipped with a reflux condenser, a thermometer, a dropping funnel and an unstirred machine
In a 300 ml glass flask, N, N'-dimethyl-1,2-
Propane diamine 51.1 g (0.50 mol), urea 60.1 g (1.
00 mol) and 100 g of 1,3,4-trimethyl-2-imidazolidinone. N, N'-dimethyl-
51.1 g (0.50 mol) of 1,2-propanediamine was prepared.
The temperature was raised to 120 ° C. for reaction. NH ₃ gas was generated with the progress of the reaction, and after about 2 hours, the generation of NH ₃ gas was stopped. Subsequently, the temperature was raised to 210 ° C. From around 200 ° C., N, N′-dimethyl-1,2-propanediamine was dropped from the dropping funnel over about 2 hours. After that, the reaction was carried out at the same temperature for 1 hour.

The mass after the reaction was measured by gas chromatography 1,3,4-
Trimethyl-2-imidazolidinone was quantified. As a result, the production yield was 96.2%. The reaction mass was distilled under reduced pressure to obtain 215.4 g of 1,3,4-trimethyl-2-imidazolidinone (fraction having a boiling point of 133 to 135 ° C./20 torr).

Example 8 Instead of the raw material N, N'-dimethyl-1,2-propanediamine, 65.1 g of N, N ', 2-trimethyl-2,3-butanediamine
(0.50 mol) was charged, and N, N ′, 2 was added to the dropping funnel.
-Trimethyl-2,3-butanediamine 65.1 g (0.50 mol)
Prepared. In addition, 1,3,4-trimethyl-2 as a solvent
-Instead of imidazolidinone, 100 g of 1,3,4,4,5-pentamethyl-2-imidazolidinone was used, and otherwise the same reaction as in Example 7 was carried out and analyzed. As a result, 1,3,4,4,5
The production yield of -pentamethyl-2-imidazolidinone is 9
It was 5.4%.

Example 9 Instead of the raw material N, N'-dimethyl-1,2-propanediamine, 65.1 g of N, N'-diethyl-1,2-propanediamine
(0.50 mol) was charged into a reaction flask, and N, N'-diethyl-1,2-propanediamine 65.1 g was added to the dropping funnel.
(0.50 mol) was prepared. Also, as a solvent, 1,3-diethyl-4-methyl-2-imidazolidinone 100 g was charged instead of 1,3,4-trimethyl-2-imidazolidinone.
Others were reacted and analyzed in the same manner as in Example 7. As a result, the production yield of 1,3-diethyl-4-methyl-2-imidazolidinone was 93.5%.

Examples 10 to 14 Example 7 except that 100 g of various solvents shown in Table 2 were used instead of the solvent 1,3,4-trimethyl-2-imidazolidinone.
Reaction and analysis were carried out in the same manner as in. 1,3 in each solvent
The production yield of 4-trimethyl-2-imidazolidinone is shown in Table 2.

[Effect of the Invention] When the 2-imidazolidinones are obtained by the reaction of the diamines of the present invention with urea, the yield can be increased by carrying out the reaction in the presence of a polar aprotic solvent with a two-step temperature gradient. It can be carried out under normal pressure if the amount of the diamines charged in the initial reaction is improved to about 1/2 mol with respect to the urea, and the diamines are added cumulatively so as to be approximately equimolar in the subsequent reaction.

Claims (4)

[Claims] 1. A formula (I) (In the formula, R is a lower alkyl group. R ¹ , R ² , R ³ and R
⁴ is a hydrogen atom or a lower alkyl group, at least one of which is a lower alkyl group. ) By the reaction of the diamine represented by
I) (Wherein, R, R ^1, R ^2, R ³ and R ^4, R, the same. As R ^1, R ^2, R ³ and R ⁴ of formula (I)) 2-imidazolidinone represented by In the presence of a polar aprotic solvent, the diamines / urea were charged at a molar ratio of 0.6 to 1.2 and reacted at 140 ° C. or lower until the formation of the urea intermediate in the initial reaction was completed. Then, the method for producing 2-imidazolidinones is characterized in that the temperature is raised to 180 ° C. or higher to react. 2. A formula (II) produced by the reaction of a polar aprotic solvent. (Wherein, R, R ^1, R ^2, R ³ and R ^4, R, the same. As R ^1, R ^2, R ³ and R ⁴ of formula (I)) 2-imidazolidinone represented by The method according to claim (1). 3. Formula (I) (In the formula, R is a lower alkyl group. R ¹ , R ² , R ³ and R
⁴ is a hydrogen atom or a lower alkyl group, at least one of which is a lower alkyl group. ) By the reaction of the diamine represented by
I) (Wherein, R, R ^1, R ^2, R ³ and R ^4, R, the same. As R ^1, R ^2, R ³ and R ⁴ of formula (I)) 2-imidazolidinone represented by In the presence of a polar aprotic solvent, the diamines / urea were charged so that the molar ratio was about 1/2, and the reaction was carried out at 140 ° C or lower until the formation of the urea intermediate in the initial reaction was completed. Continue to raise the temperature above 180 ℃ and
A method for producing 2-imidazolidinones, which comprises reacting while adding diamines so that the molar ratio of urea is approximately 2/2. 4. A formula (II) produced by the reaction of a polar aprotic solvent. (Wherein, R, R ^1, R ^2, R ³ and R ^4, R, the same. As R ^1, R ^2, R ³ and R ⁴ of formula (I)) 2-imidazolidinone represented by The method according to claim (3).