JPS62292761A - Production of 2-imidazolidinones - Google Patents

Abstract

PURPOSE:To obtain 2-imidazolidinones useful as a solvent for various characteris tic organic reactions in high yield and industrially advantageously, by reacting a diamine with urea at >= a fixed temperature in a polar solvent. CONSTITUTION:A diamine (e.g. N,N'-dimethyl-1,2-propanediamine, etc.) shown by formula I (R is lower alkyl; R<1>-R<4> are H or alkyl and at least one of them is alkyl) is reacted with urea in the presence of a polar solvent (especially preferably 2-imidazolidinone shown by formula II, reaction product of the reaction) at >=180 deg.C to give a 2-imidazolidinone (e.g. 1,3,4-trimethyl-2-imidazolidinone, etc.) shown by formula II. In the reaction, the diamine/urea are fed in a molar ratio of diamine/urea of approximately 1/2, the reaction is especially carried out at >=140 deg.C until formation of urea intermediate is completed and then the reaction is done at >=180 deg.C while adding the diamine.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the formula CI) (a R1-R2+P in which -R is a lower alkyl group)
and R+ are hydrogen atoms or lower alkyl groups, at least one of which is a lower alkyl group. ) by the reaction of diamines represented by the formula with urea (where R, R;
l, R2, R3 and R4 are formula (I) (7) R, R1
, Fu, same as R3 and R4. ) The present invention relates to a method for producing 2J imidazolidinones represented by n.

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

[Conventional technology]

Several methods for producing 2-imidazolidinones represented by the above formula (n) have been proposed. For example, 1,3.4-
For trimethyl-2-imidazolidinone, N,
A method of reacting N'-dimethyl-1,2-propanediamine with urea to obtain a yield of 75 cm [Liebig; Ann.
der Chem-), vol. 726, p. 97 (Lihe λ
Method for hydrogenating 2-ones [Liebig, Ann der Chemie]
@der Chem, ) volume 726, page 97 (19
69)) Method of reacting N,N'-dimethyl-1-1,2-propanediamine with diethylcarbamyl chloride [US Pat. No. 2,398,283 (1943)]
) etc. are known.

[Problem that the invention seeks to solve]

As mentioned above, the method of obtaining 2-imidazolidinones using diamines and urea is known, but in order to improve the operability of the reaction mass and the yield, 1.5% of the diamines are added to 1 mole of urea. It is used in mole excess.

Excess diamines are expensive and must be recovered from the reaction mass. The yield was 75 cm.

As an industrial manufacturing method, it was still unsatisfactory.

The present invention provides an industrial production method for obtaining 2-imidazolidinones represented by the above formula (n) in good yield by reacting diamines represented by the above formula (I) with urea. .

[Means to solve the problem]

The present inventors reacted the diamines represented by the above formula 〇) with urea to obtain 2-imidazolidinones represented by the above formula CI[) at low cost, in high yield, and with good operability. After intensive research into a good industrial manufacturing method, the following knowledge was obtained and the present invention was achieved.

(1) It has been found that 2-imidazolidinones can be obtained in high yield when the reaction is carried out at 180° C. or higher in the presence of a polar solvent.

Usually, in the reaction between diamines and urea, a urea intermediate of the diamine is produced before 2-imidazolidinones are produced. This intermediate often has low solubility in nonpolar solvents and precipitates out of the system. However, unless this intermediate is in a dissolved state at 180°C or higher, the ring-closing reaction to form 2-imidazolidinone is extremely slow. For this reason, it has been found that 2-imidazolidinones can be obtained in high yield when diamines and urea are reacted at 180"C or less in a polar solvent in which the urea intermediate has a high solubility.

(2) Furthermore, in the reaction of diamines and urea in a polar solvent, the reaction time is 140. React at 180"C or lower, then at 180"C
It was found that the yield could be further increased if the reaction was carried out in the above manner.

In the reaction of diamines and urea in a luminescent solvent, a temperature of 180° C. or higher is not particularly required for the initial reaction until the urea intermediate is produced. At temperatures below 100°C, the reaction slows down, but the reaction progresses satisfactorily between around 100°C and below 140°C. At temperatures above 180''C, urea itself is thermally decomposed, resulting in a loss of urea.For this reason, it has been found that the two-stage ascending reaction method allows urea to be subjected to the reaction without waste.

The end point of the reaction of the urea intermediate of diamines is easily determined by the completion of ammonia generation. In this two-stage heating method, both diamines and urea are used without waste, so there is no need to use excessive amounts of either diamines or urea.
The molar ratio of diamines/urea may be 0.6 to 1.2. Preferably, they may be prepared in approximately equimolar amounts. If too much diamine is added, an additional operation is required to recover the expensive diamine. Furthermore, if urea is charged in excess, solid impurities such as cyanuric acid, which is a thermal decomposition product of urea, remain in the reaction system, adding to the complicated solid-liquid separation operation.

(3) In addition, the present inventors further investigated the method as an industrial production method and discovered the following invention.

When the above two-stage heating method is adopted, there is no problem with the initial reaction below 140°C, but in many cases the boiling point of diamines is 1.
Since the temperature is 80°C or lower, if the temperature is raised to carry out the reaction at 180°C or higher, unreacted diamines will remain, making it difficult to carry out the reaction at normal pressure at 180°C or higher. Must react under pressure.

In order to avoid this, the present inventors charged diamines/urea in the presence of a polar solvent at the beginning of the reaction so that the molar ratio of diamines/urea was approximately V2. React below °C and continue with tS
2-imidazolidinones can be obtained in high yield even under normal conditions by reacting at 0°C or higher while adding diamines so that the overall molar ratio of diamines/urea is approximately 2/2. I found that it can be done.

The reason for this is that at the beginning of the reaction, approximately twice the molar amount of urea is charged to the diamines, so the urea intermediate produced in the initial reaction is almost completely a non-volatile diurea compound of the diamines. This is because, since no raw material diamines remain, it is possible to raise the temperature to 180°C or more even at normal pressure. Therefore, according to this method, the boiling point of the solvent is 1
If the temperature is 80° C. or higher, the entire reaction can be carried out under normal pressure. It was also found that the diamines added at 180°C or higher are effectively subjected to the reaction, and that there is no inferiority in terms of yield compared to a method in which the reaction is carried out in a two-stage temperature raising method using bulk charging.

As the solvent used in the method of the present invention, nonpolar solvents such as hydrocarbons and halogenated hydrocarbons are not suitable, but polar solvents are used.

Preferred solvents include aprotic polar solvents such as N,N'-dimethylformamide, NI-dimethylacetamide, tetramethylurea, dimethyl sulfoxide, hexamethylphosphoramide, sulfolane, methyl isobutyl ketone, nitrobenzene, tetrahydrofuran, and dioxane. can be used. In addition, if the boiling point is low, an excessively large pressure-resistant device is required, so a solvent with a boiling point of 180°C or higher is preferable. In particular, for the purpose of avoiding the complexity of solvent separation, 2-imidazolidinones produced by the reaction are the most suitable. good.

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

The 2-imidazolidinones represented by the above formula (n) obtained in the present invention are the corresponding 2-imidazolidinones obtained using the above-mentioned diamines, and are 1.3.4-1-
trimethyl-2-imidazolidinone, 1.3.4,4.
5 +1-pentamethyl-2-imidazolidine, 1.
3-diethyl-4-methyl-2-imidazolidinone and the like.

To describe a preferred and ordinary embodiment of the method of the present invention, under pressure, raw material diamines, urea, and a polar solvent are charged into an autoclave equipped with a thermometer and a mechanical stirrer, and the
The reaction is carried out by raising the temperature to 0°C or higher. There is no particular limitation as long as the temperature is 180°C or higher, but if the temperature is 300°C or higher, there are problems in terms of heating method and energy cost. When carrying out a two-stage temperature raising reaction, the reaction is carried out at 140°C or lower, and then the temperature is raised again to carry out the reaction at 180°C or higher. In the method of adding diamines at normal pressure, diamines, urea, and a polar solvent are placed in a reactor equipped with a reflux condenser, a dropping funnel with a thermometer, and a mechanical stirrer, and ammonia is added at 140°C or below. The reaction is allowed to proceed until the generation of is completed, and then the temperature is raised to 180° C. or higher, and the reaction is allowed to proceed while adding diamines from the dropping funnel. 2-imidazolidinones can be extracted from the reaction-completed liquid by distillation or the like. Especially the 2-
When imidazolidinones are used as a solvent, there is no need for separation from the solvent during distillation, resulting in an extremely simplified process.

〔Effect of the invention〕

When obtaining 2-imidazolidinones by the reaction of the diamines and urea of the present invention, the reaction temperature is 180°C in the presence of a polar solvent.
By performing the reaction at the above temperature, the desired product can be obtained in high yield with good operability without using an excessive amount of expensive diamines compared to conventional methods. In particular, if the reaction is carried out with a two-step temperature gradient, the yield will be improved.Moreover, in this case, the amount of diamines charged in the initial reaction is reduced to approximately 1/2 mole relative to urea, and the amount of diamines charged in the initial reaction is reduced to approximately 1/2 mole relative to the urea. The reaction can be carried out under normal pressure by cumulatively adding and reacting so that the reaction is carried out.

〔Example〕

Examples will be given below to explain in more detail.

Example-1 N in a 500m/stainless steel autoclave.

N'-dimethyl-1,2-propanediamine 102.2
(1,00 mol), 60.1 g (1,00 mol) of urea, and 100 g of 1,3°4-trimethyl-2-imidazolidinone. Up to reaction temperature 210°C, approx.
The temperature was raised in minutes, and the reaction was continued at that temperature for 3 hours.

After the reaction was completed, the temperature was determined to be 1°3.4 by gas chromatography.
-1-dimethyl-2-'-imidazolidinone was quantified. The production yield was 853. This reaction mass was distilled under reduced pressure to obtain 3.4-trimethyl-2-imidazolidinone (a fraction with a boiling point of 133-135°C/20 torr)2.
026F was obtained.

Example-2 Instead of the raw material N,N'-dimethyl-1,2-propanediamine, N,N;2-trimethyl-2,3-butanediamine 130.3.9 (1,flf'1 mol) and using 1.3.4.4. and instead of 1,3.4-)-tumethyl-2-imidazolidinone as solvent. - Reaction and analysis were carried out in the same manner as in Example 1, except that 100 g of 5-pentamethyl-2-imidazolidinone was used. As a result, l
, :'(, 4° The production yield of 4.5-pentamethyl-2-imidazolidinone was 84.7%.

Example-3 Instead of the raw material N,N'-dimethyl-1,2-propanediamine, N,NI=diethyl-1,2-propanediamine 130.3.9 (1,n (1 mole) was used) In addition, 1,3-diethyl-4-methyl-2- was used instead of 1,3,4-trimethyl-2-imidazolidinone as a solvent.
The reaction and analysis were conducted in the same manner as in Example 1 except that 100 g of imidazolidinone was used. As a result, the production yield of 1,3-diethyl-4-methyl-2-imidazolidinone was 8
I was in Section 33.

Examples 4 to 10 The reaction and analysis were carried out in the same manner as in Example 1, except that various solvents shown in Table 1 100.9 were used instead of 1.3.4-trimethyl-2-imidazolidinone as the solvent.

The production yields for each solvent are shown in Table 1.

Table 1 4 Toluene a15
1.2-Dichloroethane 23.76 Ethylene glycol 6α37 Isopropyl alcohol 71.98 Methyl isobutyl ketone 83.59 N-methyl-2-pyrrolidone 86.1rn
NN-dimethylacetamide 82.8 Example-
11 In a 500ml stainless steel autoclave, N, N'
-dimethyl-1,2-propanediamine 102.2. ?
(100 mol), 6.0.1 g (1,011 mol) of urea, and 109 ml of 1,3°4-trimethyl-2-imidazolidinone were charged. The temperature was raised and the reaction was carried out at a reaction temperature of 120'C for 8 hours. Continue to raise the temperature to 210″C,
The reaction was allowed to proceed for 3 hours.

After the reaction was completed, the temperature was determined to be 1°3.4 by gas chromatography.
-Trimethyl-2-imidazolidinone was quantified. 1.
The yield of 3.4-trimethyl-2-imidazolidinone was 94.9%.

Example-12 N,N',2-trimethyl-2,3-butanediamine 1303.9 (1,00 mole) was used instead of the raw material N,N-dimethyl-1,2-propanediamine, The reaction was carried out in the same manner as in Example 11, except that 1.3.4.4.5-pentamethyl-2-imidazolidinone 100I was used instead of 1,3,44h-limethyl-2-imidazolidinone as a solvent, and analysis was carried out. did. As a result, 1, 3.4.4.
The production yield of 5-pentamethyl-2-imidazolidinone was 93.3%.

Examples 13 to 16 The reaction and analysis were carried out in the same manner as in Example 11, except that 100 g of the various solvents shown in Table 2 were used instead of 1,3,4-trimethyl-2-imidazolidinone as the solvent. Table 2 shows the production yield of 1.3.4-trimethyl-2-imidazolidinone in each solvent. Table 2 16 N,N-dimethylacetamide
95.2 Example 17 In a 300 ml glass flask equipped with a reflux condenser, a thermometer, a dropping funnel, and a stirrer at 91°, N, N'
Dimethyl-1,2-propanediamine 51.1g (0,
50 mol), urea 60° 1# (1,00 mol) and 1
, 3.4-) methyl-2-imidazolidinone 100
I prepared 9. In the dropping funnel, N, NI-dimethyl-1
,2-propanediamine51. IJ (0,50-E/shi) was prepared.

The temperature was raised to 120°C to cause a reaction. As the reaction progresses, N
H3 gas was generated, and the generation of NH3 gas stopped for about 2 hours. The temperature was subsequently raised to 210''C.

N,N'-dimethyl-1,2-propanediamine was added dropwise from the dropping funnel at around 200°C over about 2 hours. Thereafter, the mixture was allowed to react at the same temperature for 1 hour.

The reaction completed mass was analyzed by gas chromatography in 1.3.
4-Trimethyl-2-imidazolidinone was quantified. As a result, the production yield was 96.2%.

This reaction mass was distilled under reduced pressure to obtain 1,3.4=-)-tmethyl-2-imidazolidinone (boiling point 133-135°C).
/20 torr fraction) 215.4 g was obtained.

Example row-18 [In place of N,N'-dimethyl-1,2-propanediamine in 4, 65.19 (0.50 mol) of N,N:2-)-trimethyl-2,3-butanediamine was added. At the same time, add N, N: 2-trimethyl-2,3 to the dropping funnel.
1.3.4.4.5-Pentamethyl-2-imidazolidinone 1oo9 was used instead of -butane/n, and the pond was reacted and analyzed as in Example 17. the result,
The production yield of 1.3.4.4.5-pentamethyl-2-imidazolidinone was 95.4%.

Example-19 Instead of the raw material N,NI-dimethyl-1,2-propanediamine, 65.1 g (0.50 mol) of N,N'-diethyl-1,2-propanediamine was charged into the reaction flask. Add N,N'-diethyl-1,2 to the dropping funnel.
-Propanediamine 65.1 # (0.50 mol) was prepared.

In addition, as a solvent, 1.3-diethyl-4-methyl-
100 J+ of 2-imidazolidinone was charged, and the pond was reacted and analyzed in the same manner as in Example 17.

As a result, the production yield of l 1,3-diethyl-4-methyl-2-imidazolidinone was 93.5%.

Examples 20 to 24 The reaction and analysis were carried out in the same manner as in Example 17, except that various solvents 100.9 shown in Table 3 were used instead of 1.3.4-trimethyl-2-imidazolidinone as the solvent. Table 2 shows the production yield of 1.3.4-)-tumethyl-2-imidazolidinone in each solvent.

Table 3 20 Tetralin 4321 1
-Chloronaphthalene 13-222 Diethylene glycol 52.923 Hexamethylphosphoramide 96.

Claims (6)

[Claims] (1) Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R is a lower alkyl group. R^1, R^2,
R^3 and R^4 are hydrogen atoms or lower alkyl groups, and at least one of them is a lower alkyl group. ) Due to the reaction between diamines and urea, the formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R, R^1, R^2, R^3 and R^ 4 is the same as R, R^1, R^2, R^3, and R^4 of formula (I). 1. A method for producing 2-imidazolidinones, which comprises reacting with: (2) Polar solvent is generated by reaction Formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R, R^1, R^2, R^3 and R^4 are , the same as R, R^1, R^2, R^3 and R^4 of formula (I).) The method according to claim (1), which is a 2-imidazolidinone represented by . (3) Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R is a lower alkyl group. R^1, R^2,
R^3 and R^4 are hydrogen atoms or lower alkyl groups, and at least one of them is a lower alkyl group. ) The reaction between the diamines represented by the formula and urea results in the formula (
II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R, R^1, R^2, R^3 and R^4 are R, R^1, R of formula (I) When obtaining 2-imidazolidinones represented by ^2, R^3 and R^4), the molar ratio of diamines/urea charged is 0.6 to 1.2 in the presence of a polar solvent. Production of 2-imidazolidinones, characterized in that the reaction is carried out at 140°C or lower until the formation of the urea intermediate in the initial reaction is completed, and then the reaction is carried out by raising the temperature to 180°C or higher. Method. (4) The polar solvent is produced by the reaction formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R, R^1, R^2, R^3 and R^4 are , the same as R, R^1, R^2, R^3 and R^4 of formula (I).) The method according to claim (3), which is a 2-imidazolidinone represented by (5) Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R is a lower alkyl group. R^1, R^2,
R^3 and R^4 are hydrogen atoms or lower alkyl groups, and at least one of them is a lower alkyl group. ) The reaction between the diamines represented by the formula and urea results in the formula (
II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R, R^1, R^2, R^3 and R^4 are R, R^1, R of formula (I) When obtaining the 2-imidazolidinones represented by ^2, R^3 and R^4), the molar ratio of diamines/urea was adjusted to approximately 1/2 in the presence of a polar solvent. The reaction is carried out at 140°C or lower until the formation of the urea intermediate in the initial reaction is completed, and then the temperature is raised to 180°C or higher to control the total diamines/
A method for producing 2-imidazolidinones, which comprises reacting while adding diamines so that the molar ratio of urea is approximately 2/2. (6) Polar solvent is generated by the reaction Formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R, R^1, R^2, R^3 and R^4 are , the same as R, R^1, R^2, R^3 and R^4 of formula (I).) The method according to claim (5), wherein .