JPH05140096A - Production of bismaleimide - Google Patents

Abstract

PURPOSE:To obtain the title high-purity compound at a low cost without complicated operations by reaction of an alkyl-substituted aromatic amine with maleic anhydride in a solvent such as an aromatic hydrocarbon into maleamic acid followed by cyclodehydration in the presence of an acid catalyst. CONSTITUTION:An alkyl-substituted aromatic diamine of e.g. the formula (R1 is 1-4C alkyl; R2 is H or 1-4C alkyl) (e.g. 3,3',5,5'-tetramethyl-4,4'- diaminodiphenylmethane) is made to react with maleic anhydride in a single solvent: an aromatic hydrocarbon (e.g. xylene) or halogenated hydrocarbon (e.g. 1,2-dichloroethane) at 141 deg.C for 3hr to produce bismaleamic acid, which is, in turn, put to cyclodehydration in the presence of an acid catalyst (e.g. p-toluenesulfonic acid), and the water produced is azeotropically distilled away; and after completing the reaction, the system is cooled to room temperature, and the reaction liquor is then dripped into pure water to effect crystal deposition, thus easily affording the objective high-purity bismaleimide at a low cost.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The bismaleimide 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. In addition, JP-A-3-868
No. 612, a method of heating in a mixed solvent of a solvent azeotropic with water and an aprotic polar solvent in the presence of a catalyst for zincs, azeotropically removing water produced, and performing a dehydration ring closure reaction. Is disclosed.

[0003]

However, the bismaleimide produced by the above-described method does not sufficiently proceed with the ring-closing reaction, and thus the bismaleimide produced contains a considerable amount of unclosed maleamic acid. Furthermore, in the production method using acetic anhydride as a dehydrating agent, the production cost is high because the amount of acetic anhydride used is large and the price is relatively high. Moreover, since acetic acid is by-produced by the reaction, a complicated process for removing it is necessary. On the other hand, when a metal such as zinc is used for the catalyst, there are various problems such as prevention of mixing and detoxification treatment. In addition, the method using a mixed solvent also requires a complicated operation in order to recover the used solvent after completion of the reaction.

[0004]

In the present invention, a diamine represented by an alkyl-substituted aromatic diamine and maleic anhydride are reacted in an aromatic hydrocarbon or halogenated hydrocarbon alone solvent to obtain a bismaleamic acid. Then, this bismaleamic acid is subjected to dehydration ring closure in the presence of an acid catalyst while removing generated water to provide a method for producing a high-purity bismaleimide.

(Diamine) Examples of the alkyl-substituted aromatic diamine used in the present invention include alkyl-substituted monocyclic aromatic diamines such as 2,4-diaminotoluene and 2,6-diaminotoluene, and 3,3'-. Dimethyl-4,
4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 3,3 '.
5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3'.5,5'-tetraethyl-
4,4'-diaminophenylmethane, 3,3'-di-n
-Butyl-4,4'-diaminodiphenylmethane, 3,
3'-di-tert-butyl-4,4'-diaminodiphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis (3-chloro-4
And alkyl-substituted polycyclic aromatic diamines such as -aminophenyl) methane. Among these, the following general formula

[0006]

[Chemical 2]

A diamine represented by the formula (wherein R ₁ represents an alkyl group having 1 to 4 carbon atoms and R ₂ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) is preferable.

(Reaction Solvent) In the method of the present invention, a single solvent of an aromatic hydrocarbon or a halogenated hydrocarbon azeotropic with water is used as a reaction solution. Examples of aromatic hydrocarbon solvents include benzene, toluene, xylene,
Examples thereof include ethylbenzene, diethylbenzene, butylbenzenes, kyumen and mesitylene. Further, as the halogenated hydrocarbon solvent, chloroform, dichloroethyne, trichloroethylene, tetrachloroethylene,
1,2-dichloroethane, 1,2-dichloropropane,
Chlorobenzene, dichlorobenzene, chlorotoluene,
Examples include trichloroethane, 1,1,2,2-tetrachloroethane and the like. The aromatic hydrocarbon solvent or halogenated hydrocarbon solvent is 1 to 5 parts by weight with respect to 1 part by weight of the polyamine.
It is used in an amount of 0 part by weight, preferably 2 to 20 parts by weight.

(Acid catalyst) As the acid catalyst used in the present invention, sulfuric acid, sulfuric anhydride, p-toluenesulfonic acid, phosphoric acid, polyphosphoric acid, metaphosphoric acid, condensed phosphoric acid, trichloroacetic acid, trifluoroacetic acid, trifluoroacetic acid. Examples include romethanesulfonic acid. The amount of these acid catalysts used is in the range of 0.0001 to 1 mol, preferably 0.001 to 0.5 mol, per 1 equivalent of the amino group of the polyamine.

(Reaction Method) For the production of bismaleimide, maleic anhydride is added to 0.1 equivalent of amino group of diamine.
9 to 2 mol, preferably 1.0 to 1.3 mol in an aromatic hydrocarbon or halogenated hydrocarbon alone solvent,
After the addition reaction in the temperature range of 0 to 150 ° C. to produce the bismaleamic acid (first step), the dehydration ring closure reaction (in the presence of an acid catalyst without isolation in the temperature range of 80 to 200 ° C.) The second step) is carried out to azeotropically remove the produced water to obtain bismaleimide.

[0011]

The present invention will be described in detail below with reference to examples. The measurement of the produced bismaleimide was performed by the following method. Melting point: Capillary method Purity: Measured as an area percentage of a liquid chromatograph (differential refractive index detector). Acid value: Titrated with N / 10 KOH ethanol drop solution for measurement.

Example 1 500 equipped with a cooler, thermometer, stirrer and water separator
3,3'-diethyl-5,5'- in a 4 ml four-necked flask.
Dimethyl-4,4'-diaminodiphenylmethane 40g
Then, 250 g of xylene was charged and the internal temperature was adjusted to 20 ° C. Next, 31 g of maleic anhydride was added little by little over 30 minutes, and after the completion, stirring was continued for 30 minutes. Subsequently, 2.7 g of paratoluenesulfonic acid was added and the temperature was raised to 1
The reaction was carried out at 41 ° C. for 3 hours. The water generated during this time was distilled out of the system together with xylene.

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 60.4 g of yellow bismaleimide. (Yield 96.3
%) This bismaleimide has a melting point of 152-157 ° C. and a purity of 9
The acid value was 6.0% and the acid value was 2.8 (mg · KOH / g).

Comparative Example 1 3,3 'was placed in a flask equipped with the same apparatus as in Example 1.
40 g of -diethyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane and 230 g of acetone were added and the internal temperature was adjusted to 20 ° C. Next, 31 g of maleic anhydride was added little by little over 30 minutes, and after the completion, stirring was continued for 30 minutes. Subsequently, 38 g of acetic anhydride and 1 of triethylamine
After adding 0 ml and 0.4 g of nickel acetate, the temperature was raised to 65 ° C for 2
Performed a time reaction.

After completion of the reaction, the mixture was cooled to room temperature and the reaction solution was added dropwise to 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 54.9 g of yellow bismaleimide. (Yield 87.6
%) This bismaleimide has a melting point of 140 to 148 ° C. and a purity of 8
The acid value was 7.1% and the acid value was 8.5 (mg · KOH / g).

Comparative Example 2 500 equipped with cooler, thermometer, stirrer and water separator
Into a four-necked flask of ml, 40 g of 4,4′-diaminodiphenylmethane and 250 g of toluene were charged and the internal temperature was 20 ° C.
Adjusted to. Next, 31 g of maleic anhydride is added in small portions of 30
The mixture was added over a period of minutes, and after the addition, the mixture was stirred for another 30 minutes. Subsequently, 2.7 g of paratoluenesulfonic acid was added and the temperature was raised, and the temperature was maintained at 110 ° C. for 20 hours, but the reaction system remained heterogeneous, the amount of water produced by the reaction was extremely small, and dehydration ring closure was performed. The reaction hardly proceeded.

Examples 2 to 5 The types of diamine, solvent, acid catalyst, slurry solvent, reaction temperature and the like were changed as shown in Table 1 to obtain bismaleimide. The results are shown in Table 1.

[0018]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // C07B 61/00 300

Claims (2)

[Claims] 1. An alkyl-substituted aromatic diamine and maleic anhydride are reacted in an aromatic hydrocarbon or halogenated hydrocarbon alone solvent to obtain a bismaleamic acid, and the bismaleamic acid is then reacted in the presence of an acid catalyst. A method for producing a bismaleimide, which comprises dehydration and ring closure, and azeotropically distilling off generated water to obtain a bismaleimide. 2. An alkyl-substituted aromatic diamine has the following general formula: (In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms, and R ₂ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
The method according to claim 1, which is represented by