JPH0637438B2 - Method for purifying bis (p-aminocumyl) benzenes - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for purifying bis (p-aminocumyl) benzenes, and more particularly to a method for purifying bis (p-aminocumyl) benzenes using a specific solvent system. .

TECHNICAL BACKGROUND OF THE INVENTION AND PROBLEMS THEREOF Bis (p-aminocumyl) benzenes are compounds useful as raw materials for synthetic resins such as polyamides, polyimides, polyamideimides and epoxies, resin additives and dyes.

Regarding the method for synthesizing the bis (p-aminocumyl) benzenes, for example, U.S. Pat. No. 3,267,145 discloses that α, α'-dihydroxy, -diisopropylpentenes and anilines as raw materials are activated clay. A method of reacting in the presence of a catalyst is disclosed, and US Pat. No. 3,365,347 discloses a method of reacting diisopropenylbenzenes and anilines in the presence of an activated clay catalyst. Further, West German Patent Nos. 2,111,193 and 2,111,194 also disclose a method for producing bis (p-aminocumyl) benzenes by a similar reaction using an acid clay catalyst.

In the method as described above, bis (p-aminocumyl) benzenes are obtained together with various reaction byproducts, and therefore it is necessary to separate and purify bis (p-aminocumyl) benzenes. However, there is no description in the above-mentioned West German patent specification about a method for purifying bis (p-aminocumyl) benzenes, and the above-mentioned US patent specification recrystallizes by a crystallization operation using ethanol or isopropanol as a solvent. It is only described to do.

However, bis (p-aminocumyl) using methanol or isopropanol taught in the above-mentioned U.S. Pat.
According to the method for purifying benzenes, there has been a problem that in the case of certain bis (p-aminocumyl) benzenes, the compound cannot be crystallized by a crystallization operation.

Further, in the case of certain bis (p-aminocumyl) benzenes, when methanol, isopropanol, or tetrahydrofuran is used, the recovery rate in the crystallization action of the compound is not very good, and the purity of the obtained purified product is also high. There was a problem that it was not always satisfactory.

The present inventors have solved the problems associated with the prior art as described above, and are capable of recovering highly pure bis (p-aminocumyl) benzenes at a high recovery rate. As a result of diligent studies on the purification method of (1), they found that the crystallization operation of the compound should be carried out using a specific solvent system, and completed the present invention.

OBJECT OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and it is possible to obtain high-purity bis (p- (p-aminocumyl) benzene from crude crystals of low-purity bis (p-aminocumyl) benzenes. -Aminocumyl) benzenes are aimed at providing a purification method capable of recovering a high recovery rate.

SUMMARY OF THE INVENTION A method for purifying bis (p-aminocumyl) benzenes according to the first aspect of the present invention is directed to a low-purity bis (p-aminocumyl) benzene.
It is characterized in that benzenes are crystallized using alkylbenzenes having 7 to 13 carbon atoms as a solvent.

Also, the bis (p-aminocumyl) according to the second aspect of the present invention
The method for purifying benzenes is to crystallize low-purity bis (p-aminocumyl) benzenes using a mixed solvent of alkylbenzenes having 7 to 13 carbon atoms and aliphatic hydrocarbons having 7 to 13 carbon atoms. It is characterized by that.

In the present invention, when purifying bis (p-aminocumyl) benzenes, alkylbenzenes having 7 to 13 carbon atoms are used as a crystallization solvent, or alkylbenzenes having 7 to 13 carbon atoms and aliphatic carbonization having 7 to 13 carbon atoms are used. Since bis (p-aminocumyl) benzenes are crystallized using a mixed solvent with hydrogen as a crystallization solvent, high-purity bis (p-aminocumyl) benzenes can be obtained with a high recovery rate.

DETAILED DESCRIPTION OF THE INVENTION The method for purifying bis (p-aminocumyl) benzenes according to the present invention will be specifically described below.

The bis (p-aminocumyl) benzenes purified in the present invention are represented by the following general formula [I].

(In the formula, R ₁ and R ₂ may be the same or different and each represents an alkyl group having 1 to 5 carbon atoms, an amino group, a halogen, a phenyl group or the like, and m and n are 0 to 0. 4.) An example of the method for producing the bis (p-aminocumyl) benzenes includes the following method.

An aromatic amine represented by the following general formula [II] is reacted with an aralkyl alcohol represented by the general formula [III] or an olein obtained by a dehydration reaction of this aralkyl alcohol in the presence of a solid acid catalyst. Obtained by

(Wherein _R 1, _{R 2} is as defined _above, R 3, _{R 4} is an alkyl group having 1 to 3 carbon atoms.) As the solid acid catalyst used during the reaction, synthetic zeolite, activated clay, Acid clay, silica-alumina, synthetic mica, acidic ion exchange resins, or those obtained by exchanging these sodium ions with other metal ions are used.

The reaction is preferably carried out in a large excess of the aromatic amines represented by the general formula [II], and usually, 1 mol of the aralkyl alcohol represented by the general formula [III] or an olefin corresponding thereto is used as an aromatic compound. It is convenient to use the group amine [II] in an amount of 4 mol or more, particularly 5 to 20 mol, because the reaction proceeds with good selectivity. In the reaction, a solvent which does not adversely influence the reaction, such as xylene, cumene or mesitylene, can be used.

The reaction temperature is preferably 60 to 260 ° C, particularly 130 to 210 ° C. The reaction time may be selected so that the reaction rate of the aralkyl alcohols represented by the general formula [III] or the olefins corresponding thereto becomes almost 100%, and it may be selected depending on the type of catalyst, reaction temperature, reaction method, etc. It may be set appropriately.

To isolate bis (p-aminocumyl) benzenes from the reaction mixture, after separating the catalyst from the reaction mixture, unreacted aromatic amine represented by the general formula [II], a solvent used in some cases, etc. And the method of cooling the reaction mixture after separating the catalyst is used.

The thus-obtained bis (p-aminocumyl) benzenes are crude crystals with low purity, and thus are purified by the purification method according to the present invention.

In the present invention, when purifying bis (p-aminocumyl) benzenes, alkylbenzenes having 7 to 13 carbon atoms are used as a crystallization solvent, and alkylbenzenes having 7 to 13 carbon atoms and 7 to 13 carbon atoms are used. A mixed solvent with an aliphatic hydrocarbon can be used.

When the number of carbon atoms of the alkylbenzenes used as the crystallization solvent is 14 or more, the solubility of bis (p-aminocumyl) benzenes in the solvent decreases, and it is difficult to remove the solvent by volatilizing the solvent after the crystallization operation. Is not preferable.

Specific examples of the alkylbenzenes having 7 to 13 carbon atoms include toluene, ethyltoluene, xylene, cumene, trimethylbenzene, diethylbenzene,
Dimethylethylbenzene, tetramethylbenzene, n-butylbenzene, isobutylbenzene, sec-bulbenzene, tert-butylbenzene, isoamylbenzene, diisopropylbenzene or a mixture thereof may be used.

Further, as the aliphatic hydrocarbon used with the above-mentioned alkylbenzenes, those having 7 to 13 carbon atoms can be preferably used. Aliphatic hydrocarbons having 1 to 4 carbon atoms cannot be used as a crystallization solvent because they are gases at room temperature, and aliphatic hydrocarbons having 5 to 6 carbon atoms have a difference in specific gravity from alkylbenzenes and may cause phase separation. Therefore, it is not preferable in general, but it is of course possible to use them in a mixed manner to the extent that they do not interfere with the operation. If the number of carbon atoms is 14 or more, it is difficult to remove the solvent by volatilizing the solvent after the crystallization operation is finished, which is not preferable.

In the present invention, when a mixed solvent of alkylbenzenes and aliphatic hydrocarbons is used as a crystallization solvent, bis (p-aminocumyl) benzenes are recovered with high purity and high recovery rate, which is preferable. In this case, it is preferable that the alkylbenzenes and the aliphatic hydrocarbons do not have a large difference in specific gravity from each other, and the mixing ratio thereof is usually 0. It is in the range of 25 to 5.

Crystallization of bis (p-aminocumyl) benzenes using such a crystallization solvent is carried out according to a conventional method. Usually, bis (p-aminocumyl) benzene which is a crude product is added to 100 parts by weight of the above solvent. About 5 to 40 parts by weight,
This solvent is heated to a temperature of 40 to 150 ° C. to dissolve the benzenes, and the resulting solution is cooled to about room temperature to crystallize bis (p-aminocumyl) benzenes. In this way, purified crystals of bis (p-aminocumyl) benzenes can be obtained, and the purity of bis (p-aminocumyl) benzenes can be further increased by repeating this crystallization operation.

Effect of the Invention In the present invention, when purifying bis (p-aminocumyl) benzenes, alkylbenzenes having 7 to 13 carbon atoms are used as a crystallization solvent, or alkylbenzenes having 7 to 13 carbon atoms and 7 to 13 carbon atoms are purified. Since bis (p-aminocumyl) benzenes are crystallized using a mixed solvent with aliphatic hydrocarbons as a crystallization solvent, high-purity bis (p-aminocumyl) benzenes can be obtained with a high recovery rate. .

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 The catalyst was filtered off from the reaction product obtained by reacting α, α′-dihydroxy-1,3-diisopropylbenzene with aniline in the presence of a solid acid catalyst, and unreacted aniline was distilled under reduced pressure. 20 g of a crude product of 1,3-bis (p-aminocumyl) benzene (purity: 85%) was obtained. The 1,3-bis (p-aminocumyl) benzene was added to 40 g of toluene, heated to 90 ° C., mixed, and then cooled to room temperature, whereupon a white powder was crystallized. The mixture was left standing at room temperature for about 1 hour and then filtered, and the powder was dried to obtain 8.6 g of 1,3-bis (p-aminocumyl) benzene. When analyzed by gas chromatography, the purity was 99.0.
%Met. The melting point of this product was 114 ° C. as measured by DSC. The solubility of 1,3-bis (p-aminocumyl) benzene in a solvent is also shown in Table 1.

Examples 2 to 12 1,3-bis (p-aminocumyl) obtained in the same manner as in Example 1
The crude product of benzene was purified by crystallization operation using various crystallization solvents shown in Table 1.

Table 1 shows the purity, recovery rate and crystal shape of the obtained purified product.

Comparative Examples 1-8 1,3-bis (p-aminocumyl) obtained in the same manner as in Example 1
The crude product of benzene was purified by crystallization operation using various crystallization solvents shown in Table 1.

Table 1 shows the purity, recovery rate and crystal shape of the obtained purified product.

Examples 13 to 19 p-diisopropenylbenzene and aniline are reacted in the presence of a solid acid catalyst to remove the catalyst from the reaction product by filtration, and unreacted aniline is removed by distillation under reduced pressure. Four-
A crude product of bis (p-aminocumyl) benzenes (purity 89%) was obtained. This 1,4-bis (p-aminocumyl) benzene was purified from various crystallization solvents shown in Table 2 by a crystallization operation.

Table 2 shows the purity, recovery rate and crystal shape of the obtained purified product.

Comparative Examples 9 to 11 The 1,4-bis (p-aminocumyl) benzene obtained in Examples 13 to 19 was used for purification by various crystallization solvents shown in Table 2 by a crystallization operation.

The results are shown in Table 2.

Examples 20 to 22 Unreacted 2,6-xylidine was removed by filtering the catalyst from the reaction product obtained by reacting p-diisopropenylbenzene with 2,6-xylidine in the presence of a solid acid catalyst. Was distilled off under reduced pressure to obtain a crude product of 1,4-bis (3,5-dimethyl-4-aminocumyl) benzene (purity: 88%). The 1,4-bis (3,5-dimethyl-4-aminocumyl) benzene was purified from various crystallization solvents shown in Table 3 by a crystallization operation.

Table 3 shows the purity, recovery rate and crystal shape of the obtained purified product.

Examples 23 to 24 p-Diisopropenylbenzene and 0-phenylenediamine are reacted in the presence of a solid acid catalyst to remove the catalyst from the reaction product by filtration, and unreacted 0-phenylenediamine is reduced in pressure. 1,4-bis (3,4-diaminocumyl) removed by distillation
A crude product of benzene (purity 74%) was obtained. The 1,4-bis (3,4-diaminocumyl) benzene was purified from various crystallization solvents shown in Table 4 by a crystallization operation.

Table 4 shows the purity, recovery rate and crystal shape of the obtained purified product.

Claims (5)

[Claims] 1. A method for purifying bis (p-aminocumyl) benzenes, which comprises crystallizing low-purity bis (p-aminocumyl) benzenes using an alkylbenzene having 7 to 13 carbon atoms as a solvent. 2. An alkylbenzene having 7 to 13 carbon atoms,
Toluene, ethyltoluene, xylene, cumene, trimethylbenzene, diethylbenzene, dimethylethylbenzene, tetramethylbenzene, n-butylbenzene, isobutylbenzene, sec-butylbenzene, tert-butylbenzene, isoamylbenzene, diisopropylbenzene or mixtures thereof. The method according to claim 1. 3. Low-purity bis (p-aminocumyl) benzenes are substituted with alkylbenzenes having 7 to 13 carbon atoms and 7 carbon atoms.
A method for purifying bis (p-aminocumyl) benzenes, which comprises crystallizing using a mixed solvent with aliphatic hydrocarbons of Nos. 13 to 13. 4. An alkylbenzene having 7 to 13 carbon atoms,
Toluene, ethyltoluene, xylene, cumene, trimethylbenzene, diethylbenzene, dimethylethylbenzene, tetramethylbenzene, n-butylbenzene, isobutylbenzene, sec-butylbenzene, tert-butylbenzene, isoamylbenzene, diisopropylbenzene or a mixture thereof. , Aliphatic hydrocarbons having 7 to 13 carbon atoms are heptane, octane, nonane, decane,
The method according to claim 3, which is undecane, dodecane, tridecane or a mixture thereof. 5. The method according to claim 3, wherein the mixing ratio, expressed as a weight ratio of the alkylbenzenes and the aliphatic hydrocarbons, is 0.25 to 5.