JPH069556A - Production of maleimide - Google Patents

Abstract

PURPOSE:To provide the method for simply producing the highly pure maleimide reduced in the content of ring-unclosed maleamic acid, facilitating the removal of an acid catalyst, etc., and not exhausting a halogen when a waste solvent is burnt. CONSTITUTION:The method for producing the maleimide is characterized by reacting an amine compound with maleic anhydride in the solvent mixture of an ester solvent with an aprotic polar solvent and subsequently subjecting the resultant maleamic acid to a dehydrative ring-closing reaction in the presence of an acid catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing maleimide. The maleimide obtained by the method of the present invention is useful as a laminate material, a sealing material, an electric insulating material, a conductive paste, an adhesive and a structural material.

[0002]

2. Description of the Related Art Conventionally, as a method for producing maleimide,
For example, JP-B-59-52660 and JP-A-63-661.
No. 64 discloses a ketone solvent such as acetone or N, N.
-A method of dehydration ring closure reaction by adding a base such as triethylamine and a metal compound using a dehydrating agent such as acetic anhydride in the presence of a polar solvent such as dimethylformamide, and JP-A-60-260623, 63-301226. In the gazette,
A method is disclosed in which a polyamine and maleic anhydride are reacted in a mixed solvent of an aromatic hydrocarbon or a halogenated hydrocarbon and an aprotic polar solvent to obtain a polyamic acid, and then a dehydration ring-closing reaction is performed.

[0003]

However, the above-mentioned method using a dehydrating agent does not allow the ring-closing reaction to proceed sufficiently, and the bismaleimide produced contains a considerable amount of unringed maleamic acid. Furthermore, the production method using acetic anhydride as a dehydrating agent has problems that the amount of acetic anhydride used is large, the production cost is high, and a complicated step of removing acetic acid by-produced by the reaction is required. Further, when a metal is used for the catalyst, there are various problems such as prevention of mixing and detoxification treatment are required.

Further, in the method of dehydration ring closure in a mixed solvent of an aromatic hydrocarbon and an aprotic polar solvent, the maleimides react with the aromatic hydrocarbon solvent during the water washing step for removing the acid catalyst and the like. There is a problem that it is difficult to wash with water because of poor solubility and easy precipitation. In addition, the method using a halogenated hydrocarbon is not preferable in terms of environmental hygiene because the halogenated hydrocarbon is discharged when the waste solvent is incinerated.

[0005]

In the present invention, amines and maleic anhydride are reacted in an ester solvent and an aprotic polar solvent to obtain maleamic acid, which is then reacted in the presence of an acid catalyst. The present invention provides a method for easily producing highly pure maleimide, characterized by performing a dehydration ring closure reaction.

(Amines) Examples of amines used in the present invention include (1) aromatic monoamines such as aniline, toluidine, chloroaniline and bromoaniline; alicyclic monoamines such as cyclohexylamine; and trimethylenediamine. , Tetramethylenediamine, hexamethylenediamine, xylylenediamine, 3,9-bis (3-aminopropyl)-
Aliphatic diamines such as 2,4,8,10-tetraoxaspiro [5,5] undecane, bis (4-aminocyclohexyl) methane, m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylmethane,
4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 2,2-bis- (4-aminophenyl) propane ,
Bis- (4-aminophenyl) diphenylsilane, bis- (4-aminophenyl) methylphosphine oxide, bis- (3-aminophenyl) methylphosphine oxide, bis- (4-aminophenyl) -phenylphosphine oxide, bis- (4-Aminophenyl) phenylamine, 1,5 diaminonaphthalene, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,3'-
Dimethyl-4,4'-diaminophenylmethane, 3,
3'-diethyl-5,5'-dimethyl-4,4'-diaminophenylmethane, 3,3'.5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 3,3'-
Diethyl-4,4'-diaminodiphenylmethane, 3,
3'.5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-di-n-butyl-4,4 '
-Diaminodiphenylmethane, 3,3'-di-tert
-Butyl-4,4'-diaminodiphenylmethane, 2,
2-bis- [4- (4-aminophenoxy) phenyl]
Aromatic diamines such as propane, bis [4- (4-aminophenoxy) phenyl] sulfone, and bis (3-chloro-4-aminophenyl) methane.

(2) Aromatic polyamine obtained by condensation reaction of aniline and formaldehyde (JP-A-50-
No. 21098). (3) A tetrafunctional aromatic polyamine which is a reaction product of an aromatic dialdehyde and an aromatic amine (JP-A-59-12).
931). (4) An aromatic polyamine obtained from a mixture of aromatic dialdehyde and formaldehyde and an aromatic amine (see JP-A-60-26032). (5) Other polymers of vinylaniline, triaminobenzene, triaminotoluene, triaminonaphthalene, triaminodiphenyl, triaminopyridine, triaminophenyl ether, triaminodiphenylmethane, triaminodiphenyl sulfone, triaminobenzophenone, Triaminophenyl orthophosphate, tri (aminophenyl) phosphine oxide, tetraaminobenzophenone, tetraaminobenzene, tetraaminonaphthalene, diaminobenzidine, tetraaminophenyl ether, tetraaminophenylmethane, tetraaminophenyl sulfone, bis (diaminophenyl) pyridine , Melamine etc. Is mentioned.

(Reaction Solvent) In the method of the present invention, a mixed solvent of an ester solvent and an aprotic polar solvent is used as a reaction solvent. Specific examples of the ester solvent include ethyl formate, n-butyl formate, ethyl acetate, propyl acetate, n-butyl acetate, isobutyl acetate, sec acetate.
-Hexyl, 2-ethylhexyl acetate, ethyl propionate, n-butyl propionate, ethyl isovalerate and other aliphatic esters, dimethyl maleate and other aliphatic diesters, methyl benzoate and other aromatic esters, γ-butyrolactone, etc. And cyclic ester of carbitol acetate and the like. Of these, represented by the general formula, R ₁ COOR ₂ [wherein R ₁ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ₂ represents an alkyl group having 1 to 10 carbon atoms]. Aliphatic esters are preferred.

As the aprotic polar solvent, a solvent which easily dissolves amic acid, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-
2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, amide solvents such as tetramethylurea, sulfur solvents such as dimethylsulfoxide, phosphorus solvents such as hexamethylphosphoramide, and the like, and amides. A system solvent is preferably used. These aprotic polar solvents are
A substance having a boiling point of 150 ° C. or higher and hardly azeotropic with water is preferable.

The amounts of the ester solvent and the aprotic polar solvent in the mixed solvent are preferably such that the amount of the aprotic polar solvent is small, and the amount of the aprotic polar solvent in the mixed solvent is 0.
It is 1 to 30% by weight, preferably 1 to 20% by weight. The reaction solvent is 1 to 50 parts by weight with respect to 1 part by weight of amines,
It is preferably used in a proportion of 2 to 20 parts by weight.

(Acid catalyst) As the acid catalyst used in the dehydration ring-closing reaction, inorganic acid catalysts such as sulfuric acid, sulfuric anhydride, phosphoric acid, polyphosphoric acid, metaphosphoric acid and condensed phosphoric acid, and p-toluenesulfonic acid, Trichloroacetic acid, trifluoroacetic acid,
Examples thereof include organic acid catalysts such as trifluoromethanesulfonic acid, and organic acid catalysts are preferably used. The amount of these acid catalysts used is 0.00 with respect to 1 equivalent of amino groups of amines.
It is in the range of 01 to 1 mol, preferably 0.001 to 0.5 mol.

(Reaction Method) Maleimide is prepared by adding maleic anhydride to 0.9 to 1 equivalent of amino group of amines.
Addition reaction is carried out in the temperature range of 0 to 130 ° C. in the organic solvent in an amount of 2 mol, preferably 1.0 to 1.3 mol to produce maleamic acid (first step). After the first-stage reaction, without isolating the maleamic acid, a predetermined amount of an acid catalyst was added to the reaction system, and the temperature was raised to carry out a dehydration ring-closing reaction while azeotropically distilling generated water with a reaction solvent. , Maleimide is obtained (second stage).

In the dehydration ring-closing reaction, the produced water is azeotropically distilled off in the temperature range of 50 to 200 ° C., preferably 80 to 160 ° C. to perform the dehydration ring-closing reaction to obtain maleimide. Reaction temperature is 5
If the temperature is lower than 0 ° C, the dehydration reaction is difficult to proceed,
If the temperature exceeds ℃, the amount of polymer produced increases. The organic solvent azeotroped with the produced water is immediately cooled and phase-separated, and then returned to the reaction system again to carry out the reaction.

(Post-treatment method) After the reaction, with respect to 1 part by weight of the produced maleimide contained in the organic solvent reaction solution,
0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight of water is added, and after stirring, the mixture is allowed to stand, separated from oily water, and washed.
Stirring is generally 3 to 3 at a rotation speed of 30 to 300 rpm.
It is performed by stirring for 0 minutes. Washing is 20-9
It is performed 1 to 5 times, preferably 2 or more times, in a temperature range of 5 ° C. After washing with water, the solvent is distilled off, until substantially no solvent is removed, or maleimide is extracted in a molten state, or water, methanol, with respect to maleimide such as ethanol, by adding a poor solvent, High-purity maleimide is obtained by taking out in a crystalline state.

[0015]

The present invention will be described in detail below with reference to examples. Example 1 500 with cooler, thermometer, stirrer and water separator
In a ml four-necked flask, 40 g of 4,4'-methylenedianiline, 280 g of n-butyl acetate and 10 g of N-methyl-2-pyrrolidone were charged and dissolved while adjusting the internal temperature to 20 ° C. Next, 43.6 g of maleic anhydride was added little by little over 30 minutes, and after the completion, stirring was continued for 30 minutes. Subsequently, 3.8 g of para-toluenesulfonic acid was added and the temperature was raised, and the temperature was kept at 128 ° C. for 4 hours to carry out the reaction.
The water generated during this time was distilled out of the system together with n-butyl acetate.

After the reaction was completed, the product was washed with 200 g of pure water three times,
Then, in an oil bath maintained at a temperature of 80 ° C, under reduced pressure (100
210 g of n-butyl acetate was distilled off at ˜20 mmHg). After cooling the reaction solution to 50 ° C., 250 g of methanol was added to the reaction solution to obtain a slurry solution. This was separated by filtration and dried to obtain 67.2 g of pale yellow bismaleimide powder. (Yield 92.9%) The melting point of this bismaleimide by the capillary method is 156 to 159 ° C., the purity measured by the area percentage of the liquid chromatograph (differential refractive index detector) is 94.8%, and the N / 10KOH ethanol solution is used. The acid value was 3.0 (mgKOH / g).

Comparative Example 1 4,4 'was placed in a flask equipped with the same apparatus as in Example 1.
-Methylenedianiline (40 g) and acetone (230 g) were added to adjust the internal temperature to 20 ° C. Then maleic anhydride 43.
Add 6g little by little over 30 minutes, then add 3 more
Stir for 0 minutes. Subsequently, 54 g of acetic anhydride, 10 ml of triethylamine and 0.4 g of nickel acetate were added and the temperature was raised to carry out a reaction at 65 ° C. for 2 hours.

After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was dropped into 1000 ml of pure water to precipitate crystals. The crystals were separated by filtration, washed twice with 1000 ml of pure water and dried to obtain 67.5 g of yellow bismaleimide. (Yield 9
3.3%) The melting point of this bismaleimide is 143-148.
℃, purity 88.0%, acid value 11.5 (mg · KOH /
g).

Comparative Example 2 500 equipped with a cooler, thermometer, stirrer and water separator
In a ml four-necked flask, 40 g of 4,4'-diaminodiphenylmethane, 250 g of toluene and N-methyl-2.
-Pyrrolidone 10 g was dissolved while adjusting the internal temperature to 20 ° C. Next, maleic acid (43.6 g) is added in small amounts to 30
The mixture was added over a period of minutes, and after completion, the mixture was stirred for another 30 minutes. Subsequently, 3.8 g of paratoluenesulfonic acid was added and the temperature was raised,
The reaction was carried out by keeping the temperature at 112 ° C. for 5 hours. Water generated during this time was distilled out of the system together with toluene. After completion of the reaction, the product was washed once with 200 g of pure water, and a viscous bismaleimide was deposited, which made it impossible to separate oil and water. Therefore, the subsequent operations were not performed.

Examples 2 to 6 Maleimides were obtained in the same manner as in Example 1 except that the kind of amine, solvent, acid catalyst and reaction temperature were changed as shown in Table 1. The results are summarized in Table 1.

[0021]

[Table 1]

* 1: 4,4'-methylenedianiline * 2: 2,2'-bis [4- (4-aminophenoxy)
Phenyl] propane * 3: 3,3'-diethyl-5,5'dimethyl-4,
4'-Diaminodiphenylmethane * 4: Metaphenylenediamine * 5: Polyamine obtained from aniline and formaldehyde, Mitsui Toatsu Co., Ltd. product name * 6: Obtained from aniline 4 mol, O-toluidine 4 mol, terephthalaldehyde 1 mol Polyamine * 7: Butyl acetate * 8: N-methyl-2-pyrrolidone * 9: Ethyl acetate * 10: Dimethylformamide * 11: Butyl propionate * 12: Dimethylacetamide * 13: Paratoluenesulfonic acid

Claims (4)

[Claims] 1. A maleic acid is obtained by reacting an amine with maleic anhydride in a mixed solvent of an ester solvent and an aprotic polar solvent, and the maleamic acid is subjected to a dehydration ring-closing reaction in the presence of an acid catalyst. A method for producing a maleimide, comprising: 2. The ester solvent is of the general formula R ₁ COOR ₂
[In the formula, R ₁ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ₂ represents an alkyl group having 1 to 10 carbon atoms. ] The method of Claim 1 represented by these. 3. The method according to claim 1, wherein the aprotic polar solvent is an amide solvent. 4. The method according to claim 1, wherein the acid catalyst is an organic acid catalyst.