JP3025319B2 - N-substituted maleimide and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel N-substituted maleimide and a method for producing the same.

[0002]

2. Description of the Related Art N-substituted maleimides have hitherto been used as a heat-resistant modifier for thermoplastic resins such as polyvinyl chloride, polystyrene and ABS, and as raw materials for pharmaceuticals and agricultural chemicals, and are particularly used in the field of thermoplastic resins. Make up the majority.

[0003] N-phenylmaleimide is known as an N-substituted maleimide used in the field of thermoplastic resins. However, N-phenylmaleimide itself is yellow, so when it is mixed with a resin, it is added. The resin has a drawback that it takes on a yellow color, and its use is restricted to applications requiring transparency. Further, in order to solve the drawback, N-cyclohexylmaleimide is partially used. However, although the resin is less likely to take on a yellow color, the improvement in heat resistance as a heat resistance modifier has been insufficient and has been satisfied. Not in.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel N-substituted maleimide which is not yellowish in itself and has excellent white heat resistance.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned objects, and as a result, have completed the present invention. That is, the present invention provides a compound represented by the general formula (I)
(Formula 3 )

[0006]

Embedded image (Wherein, R ₁ represents a hydrogen atom, R ₂ to R ₆ and X
₁ and X ₂ are a hydrogen atom, a halogen atom, or a group having 1 to 1 carbon atoms.
Novel N- substituted maleimide and represented by the general formula shows the 10 alkyl group) (II) (of 4)

[0007]

Embedded image (Wherein, R ₁ to R ₆ and X _1, X ₂ of the general formula (I) and same content showing a) at represented in N- substituted maleimide for causing cyclodehydration reaction luma Reamido acid It relates to a manufacturing method.

[0008] maleamic acid represented by the general formula (II) used in the present invention, one general formula (III) (Formula 5)

[0009]

Embedded image (Wherein, R _{1 to} R ₆ have the same content as in the general formula (I))
And an alicyclic amine compound represented by the general formula (IV)
6 )

[0010]

Embedded image (Wherein, X ₁ and X ₂ have the same contents as in the general formula (I))
And maleic anhydride or a derivative thereof is subjected to an addition reaction.

The alicyclic amine compound used in the present invention is represented by the general formula (III). The alkyl group of R _{2 to} R ₆ includes isomers such as normal and iso. Specifically, cyclohexylmethyl amine, 4 - methylcyclohexyl methyl amine, 4 - ethyl cyclohexylmethyl amine, 2, 4-dimethyl-cyclohexylmethyl amine, 2, 4-diethyl-cyclohexylmethyl amine,
2, 4,6-trimethyl-cyclohexylene Rume ethylamine,
2, etc. 4,6 triethyl cyclohexylmethyl Amin of <br/> the like. Further, those having two substituents on the carbon of the cyclohexane ring, such as 1,3,3-trimethylcyclohexylmethylamine, can also be used.

On the other hand, maleic anhydride or a derivative thereof used in the reaction with an alicyclic amine compound has the general formula (IV)
And specifically, maleic anhydride, 3-methylmaleic anhydride, 3-ethylmaleic anhydride, 3,4-
Examples thereof include dimethyl maleic anhydride, 3,4-diethyl maleic anhydride, 3-chloromaleic anhydride, and 3,4-dichloromaleic anhydride.

The above-mentioned alicyclic amine compound is subjected to an addition reaction with maleic anhydride or a derivative thereof to obtain maleamic acid. In the method of the present invention, maleic anhydride or maleic anhydride is added to 1 mol of the alicyclic amine compound. 0.6-
The reaction is carried out using a 1.5-fold molar range. More preferably, it is 0.8 to 1.2 times mol.

In the reaction, it is preferable to use a solvent, for example, an aliphatic hydrocarbon such as hexane, heptane and cyclohexane, an aromatic hydrocarbon such as benzene, toluene and xylene, and a halogen such as chlorobenzene and dichlorobenzene. An aprotic polar solvent such as a system aromatic hydrocarbon, dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide and the like, and a mixed solvent thereof can be used. More preferred are aprotic polar solvents such as dimethylformamide.

The amount of the solvent used is 1 to 20 times (by weight) the amount of the starting amine compound, more preferably 2 to 20 times.
10 times (weight).

[0016] In the reaction, it may be charged the total amount of maleic anhydride and starting material amine compound from the start, but is preferably gradually added either order with a fever. More preferably, maleic anhydride is completely dissolved in the solvent,
The temperature in the reactor is 120 ° C or less, preferably 30 to 100 ° C
It is preferred that the raw material amine compound is added dropwise while stirring so as to be maintained in the range described above. At this time, the raw material amine to be dropped may be dissolved in the same solvent as the reaction solvent.

The time for dropping the starting amine is preferably from 5 to 180 minutes, more preferably from 30 to 120 minutes. After completion of the dropwise addition, the dehydration ring-closing reaction can be carried out immediately, but it is preferable that the maleamic acid is aged at 30 to 120 ° C for about 0.5 to 3.0 hours, more preferably at 50 to 100 ° C for 1 hour. .0
Aging is preferably performed for about 2.0 hours.

The general formula (II) obtained by the above reaction
For the dehydration ring closure reaction for obtaining the N-substituted maleimide represented by the general formula (I) from the maleamic acid represented by
The method is not particularly limited, and a method known per se can be adopted.

In the method of the present invention, a catalyst can be used if necessary. As the catalyst to be used, for example, p
- toluenesulfonic acid, benzenesulfonic acid, an organic acid or orthophosphoric acid such as methanesulfonic acid, polyphosphoric acid, Metason acids, metal-containing compound such as an inorganic acid or zinc, such as sulfuric acid, preferably a metal oxide such as ZnO _2, SnO ₂ Can be used. More preferred are organic acids such as orthophosphoric acid and polyphosphoric acid.

The amount of the catalyst used is preferably 0.1 to 200 parts by weight, more preferably 2 to 100 parts by weight, per 100 parts of maleamic acid.

The reaction temperature in the dehydration ring closure reaction is from 50 to
The temperature is preferably in the range of 180 ° C, more preferably 60 to 16 ° C.
The reaction is preferably performed at about 0 ° C.

The reaction time is about 1 to 100 hours, more preferably 1 to 50 hours.

After completion of the reaction, after removing a by-product or an acid catalyst, purification can be performed by distillation or sublimation purification. Preferably, the N-substituted maleimide represented by the general formula (I) can be obtained with high purity by recrystallization after washing with water or alkali. The N-substituted maleimide represented by the general formula (I) of the present invention obtained as described above is a pure white crystal which is not colored yellow like a conventional aromatic N-substituted maleimide and is heat stable. Excellent in nature.

[0024]

The present invention will be described in more detail with reference to the following examples. Example 1 Stirrer, cooling condenser, thermometer, nitrogen gas inlet tube,
4.8 g (0.049 mol) of maleic anhydride and 10 g of dimethylformamide were charged into a 100 ml glass four-necked flask equipped with a dropping funnel, and completely dissolved while heating to 60 ° C. Into the mixture, 5.0 g (0.044 mol) of cyclohexanemethylamine was added dropwise over 1 hour while paying attention to the reaction temperature, and the mixture was aged at 60 ° C. for 2 hours to synthesize maleimidic acid. Next, after charging 10 g of polyphosphoric acid of the above reaction solution, the temperature was raised while paying attention to the reaction temperature, and a dehydration ring closure reaction was performed at 90 to 95 ° C. for 24 hours. After the completion of the reaction, the mixture is cooled to room temperature and discharged into 100 g of water.
After washing with alkali, the precipitated crystals are separated by filtration. Further washing with 5 g of methanol gave white crystals. The weight after drying was 5.3 g. As a result of HPLC analysis, the crystals contained a trace amount of impurities. The crystals were recrystallized from ethyl acetate to obtain 4.8 g of white crystals. Purity: 99.9%. The crystals were identified as N-cyclohexylmethylmaleimide from the results of elemental analysis, ¹ H-NMR, and IR analysis.
The measurement results are shown below. Elemental analysis value (%) (calculated as C ₁₁ H ₁₅ NO ₂ )

[0025]

[Table 1] FIG. 1 shows the IR spectrum (KBr method). Table 2 shows the results of the thermophysical property test.

Comparative Example 1 A stirrer, cooling condenser, thermometer, nitrogen gas inlet tube,
5.4 g (0.055 mol) of maleic anhydride and 10 g of dimethylformamide were charged into a 100 ml glass four-necked flask equipped with a dropping funnel, and completely dissolved while heating to 60 ° C. 5 g (0.050 mol) of cyclohexylamine in 1 while paying attention to the reaction temperature.
The solution was dropped over a period of time, and aged at 60 ° C. for 2 hours to synthesize maleamic acid. Next, after charging 10 g of polyphosphoric acid to the reaction solution, the temperature was raised while paying attention to the reaction temperature.
A dehydration ring closure reaction was performed at 90 to 95 ° C. for 24 hours. After completion of the reaction, the mixture was cooled and extracted with 14 g of ethyl acetate. The layers were separated.
~ 130 ° C / distilled at 2-3mmHg, 6.0g of white crystals
I got Table 2 shows the results of the thermophysical property test.

[0027]

[Table 2] As shown by the thermophysical property test results, the N-phenylmaleimide of Reference Example has excellent thermal stability, but has a drawback of being yellowish. Further, the N-cyclohexylmaleimide of Comparative Example 1 is white and has no problem in transparency, but has a disadvantage of poor thermal stability. Therefore, the N-substituted maleimide of the present invention has an excellent feature that can solve both disadvantages.

[0028]

The N-substituted maleimide represented by the general formula (I) using the alicyclic amine compound obtained by the present invention is a novel compound, and has a higher fatty acid content than the conventional aromatic N-substituted maleimide. Since it has the characteristic of not having a yellow color peculiar to a cyclic compound, is pure white, and has a high thermal decomposition temperature, it is useful as a heat resistance improver for thermoplastic resins and the like.

[Brief description of the drawings]

FIG. 1 is an IR spectrum of N-cyclohexylmethylmaleimide obtained in Example 1.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akihiro Yamaguchi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Mitsui Toatsu Chemicals Co., Ltd. Examiner Takeshi Nimi (56) References Pharmaco-Ed. Sc. , Vol. XX, fasc. 12 (1965) p. 842-859 (58) Field surveyed (Int. Cl. ⁷ , DB name) CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A compound of the general formula (I) (Wherein, R ₁ represents a hydrogen atom, R ₂ to R ₆ and X
₁ and X ₂ are a hydrogen atom, a halogen atom, or a group having 1 to 1 carbon atoms.
N-substituted maleimide represented by the following formula: 2. A compound of the general formula (II) The method for producing an N-substituted maleimide according to claim 1, wherein the maleamic acid represented by the formula (wherein R _{1 to} R ₆ and X ₁ and X ₂ have the same content as in the general formula (I)) is subjected to a dehydration ring closure reaction.