JPH05320101A - Production of high-purity aliphatic diamine - Google Patents

Abstract

PURPOSE:To obtain a high-purity aliphatic diamine by efficiently removing nitriles and amides contained in an aliphatic diamine obtained by hydrogenating an aliphatic dinitrile. CONSTITUTION:The method for producing a high-purity aliphatic diamine is characterized by subjecting an aliphatic diamine obtained by hydrogenation of an aliphatic dinitrile and containing at least mononitrile and/or monoamide as impurities to hydrolysis, converting the nitrile and/or amide into a carboxylic acid and then separating and recovering the aliphatic diamine from the resultant hydrolysate.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a high-purity aliphatic diamine.

[0002]

2. Description of the Related Art In order to produce an aliphatic diamine, a method of hydrogenating an aliphatic dinitrile and converting the nitrile group into an amino group is widely used. Then, in the aliphatic diamine obtained by this method, in addition to a by-product produced by hydrogenation of the raw material dinitrile, a monoamide compound contained in the raw material dinitrile is mixed as an impurity. Aliphatic diamines containing such impurities are usually purified by distilling them, but in this case, their nitriles and amides have similar boiling points to the aliphatic diamines, so be sure to separate them completely. It is difficult.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a method for efficiently removing nitriles and amides mixed in an aliphatic diamine obtained by hydrogenating an aliphatic dinitrile to obtain a highly pure aliphatic diamine. That is the subject.

[0004]

As a result of intensive studies to solve the above-mentioned problems, the present inventors hydrolyzed aliphatic diamines and converted nitriles and amides mixed therein into carboxylic acid forms. By doing so, they found that those impurities could be easily removed, and completed the present invention. That is, according to the present invention, an aliphatic diamine containing at least mononitrile and / or monoamide as an impurity obtained by hydrogenation of an aliphatic dinitrile is hydrolyzed to convert the nitrile and / or amide into a carboxylic acid. After that, a method for producing a high-purity aliphatic diamine, which comprises separating and recovering the aliphatic diamine from the obtained hydrolysis product, is provided.

The aliphatic diamine to be treated in the present invention is obtained by hydrogenating an aliphatic dinitrile as a raw material and is represented by the following general formula. H ₂ N—R—NH ₂ (1) In the above formula, R is an aliphatic group and includes a saturated or unsaturated hydrocarbon group such as an alkylene group or an alkenylene group. In addition, these alkylene groups and alkenylene groups can be linear or branched, and the number of carbon atoms is
Usually, it is 5 to 20. Specific examples of the aliphatic diamine used as the raw material to be treated in the present invention include, for example, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-
Examples thereof include diaminononane and 1,10-diaminodecane. These aliphatic diamines can be used alone or as a mixture.

In the aliphatic diamine used as the raw material to be treated in the present invention, the following compounds are usually mixed as impurities. (1) Intermediate mononitrile _{H 2 N-A'-CN (} 2) (2) dialkylamine _{H 2 N-A-NH-} A-NH 2 (3) (3) intermediate monoamide NC-A '' - CONH ₂ (4) In the above formula, A is the same as A in the general formula (1), A ′ is an aliphatic group having one less carbon atom than A, and A ″ is less than A. Each of the aliphatic groups having two carbon atoms is shown. The mononitrile and dialkylamine represented by the formulas (2) and (3) are by-products of the hydrogenation process of the aliphatic dinitrile, while the monoamide represented by the formula (4) is a hydrogenation raw material. It was contained in the aliphatic dinitrile. The problem in the production of high-purity aliphatic diamine is the mononitrile of formula (2) and the monoamide of formula (4), which have similar boiling points to the aliphatic diamine, and the dialkylamine of formula (3) is at room temperature. Since it is easy to separate and remove in a solid state, there is no particular problem. The mononitrile of the formula (2) is usually mixed in the aliphatic diamine in a proportion of 0.1 to 30% by weight, and
The monoamide of formula (4) is usually incorporated in a proportion of 0.5% by weight. The dialkylamine of the formula (3) is usually mixed in a proportion of 5 to 20% by weight or less. In the present invention, the raw material aliphatic diamine may be mixed with the mononitrile and the amide alone, or both of them may be similarly mixed. In the present invention, the aliphatic diamine containing the impurities is hydrolyzed to convert the mononitrile and monoamide into corresponding carboxylic acids, and then the aliphatic diamine is separated and recovered from the obtained hydrolysis product.

The hydrolysis treatment of the aliphatic diamine containing impurities is carried out in the presence of water and under heating. In this case, a base such as an alkali metal hydroxide or an alkaline earth metal hydroxide can be present in the reaction system as a reaction accelerator. As the base, any base can be used as long as it reacts with a carboxylic acid to give a neutralized salt which is solid at room temperature. Examples of such substances include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, and alkaline earth metal hydroxides such as calcium hydroxide, magnesium hydroxide and beryllium hydroxide. Can be mentioned.

In the hydrolysis treatment of the aliphatic diamine containing impurities according to the present invention, when the reaction accelerator is not present in the reaction system, it is stirred at 140 ° C. in a pressure resistant reaction vessel.
As described above, the reaction is preferably performed at a temperature of 160 to 200 ° C. On the other hand, when an alkali metal hydroxide is used as the reaction accelerator, the temperature is 80 ° C. or higher, preferably 100 at normal pressure while stirring in a reaction vessel equipped with a cooling pipe.
It is advisable to carry out the reaction under reflux at about 110 ° C. When an alkaline earth metal hydroxide is used as the reaction accelerator, the reaction is performed at 100 ° C or higher, preferably 140 to 200 ° C while stirring in a pressure resistant reaction vessel, or a cooling pipe is attached. It is advisable to carry out the reaction in a reaction vessel at 100 ° C. or higher, preferably around 110 ° C. under reflux under normal pressure while stirring.

In the hydrolysis treatment of the present invention, the amount of water added is 25 with respect to the raw material aliphatic diamine.
It is in the range of not less than wt%, preferably 40 to 50 wt%. Generally, 5 mol or more, preferably 10 to 1 mol of mononitrile contained in the raw material aliphatic diamine.
It may be 15 mol. The amount of the reaction accelerator added to the raw material aliphatic diamine is 2% by weight or more, preferably 4 to 10% by weight. Generally, 0.1 mol per mol of mononitrile contained in the raw material aliphatic diamine.
It may be 5 mol or more, preferably 1 to 2 mol. The hydrolysis reaction time in the present invention varies depending on the reaction conditions, but is usually 2 to 8 hours. In general, according to the above-mentioned hydrolysis treatment in which it is preferable to make the reaction end point when mononitrile disappears, both mononitrile and monoamide contained as impurities are hydrolyzed to the corresponding carboxylic acid or its salt. To be converted. Any of these carboxylic acids or salts thereof can be easily separated from the aliphatic diamine.

As a method for separating and recovering the aliphatic diamine from the hydrolysis product obtained by the hydrolysis treatment of the present invention, an appropriate method is adopted depending on the properties of the hydrolysis product. The specific method is shown below. (1) Hydrolysis product containing no reaction accelerator The hydrolysis product in this case contains, as impurities, a free carboxylic acid derived from mononitrile or monoamide and a dialkylamine which is solid at room temperature. And, both of these free carboxylic acids and dialkylamines have higher boiling points than the aliphatic diamines. Therefore, this hydrolysis product can be easily obtained as a distillate of high-purity aliphatic diamine by subjecting it to a distillation treatment. The distillation conditions in this case differ depending on the type of the aliphatic diamine, but in general, under the pressure of about 3 mmHg, the column top temperature: 50 to 200 ° C., the column bottom temperature: 80 to 250 ° C. Purified aliphatic diamine can be obtained as an overhead product. Further, as another method for separating the aliphatic diamine from the hydrolysis product, a solid neutralized salt is prepared by adding a base to the hydrolysis product to neutralize free carboxylic acid contained as an impurity. After that, the solid neutralized salt contained as impurities and the solid dialkylamine are separated and removed by a solid-liquid separation method such as filtration or centrifugation, and then water is removed from the obtained aliphatic diamine. By doing so, a high-purity aliphatic diamine can be obtained. Further, the aliphatic diamine can be obtained with high purity and efficiency by subjecting the product obtained by neutralizing the hydrolysis product with a base to the distillation treatment as it is. Any base can be used as the base as long as it reacts with a carboxylic acid to produce a solid neutralized salt. Examples of such substances include the above-mentioned alkali metal hydroxides and alkaline earth hydroxides. In the solid-liquid separation, the operating temperature is room temperature to 10
A temperature of 0 ° C., preferably 30-50 ° C. is adopted.

(2) Hydrolysis Product Containing Reaction Accelerator In the hydrolysis product in this case, the carboxylic acid contained as an impurity is converted into a solid neutralization salt form. Therefore, the hydrolysis product in this case is subjected to solid-liquid separation treatment to remove the carboxylic acid neutralizing salt and dialkylamine contained therein, and then removes water from the obtained aliphatic diamine. As a result, the aliphatic diamine can be separated with high purity. As a matter of course, the above-mentioned hydrolysis product is treated by distillation as it is, or after neutralizing salts and dialkylamines contained in the hydrolysis product are roughly removed by solid-liquid separation treatment and then subjected to distillation treatment to obtain fat. The group diamine can be obtained in high purity.

[0012]

According to the present invention, it is possible to efficiently obtain a high-purity aliphatic diamine from an aliphatic diamine containing mononitrile or monoamide as an impurity, which has been considered difficult to separate and remove. You can
According to the present invention, an aliphatic diamine having a purity of 99.9% by weight or more, which is suitable as a raw material for polymers such as polyamide, can be easily obtained.

[0013]

EXAMPLES Next, the present invention will be described in more detail by way of examples. In addition, the test diamine A used in the examples,
B and C are synthesized as follows. (1) Tested diamine A Adiponitrile (Tokyo Kasei) was used to diamine by hydrogenation. As a result, the purity of the obtained diamine was 66.9% by weight, and this diamine contained 25.6% by weight of mononitrile and 7.5% by weight of dialkylamine as impurities. (2) Sample diamine B Azelaic acid manufactured by Emery Co., Ltd., EMEROX 1144 (polymer grade) was used as a raw material, and dehydration and ammonia addition reaction were performed to dinitrile (purity 9 of dinitrile).
8.3% by weight). Yield 8 by distilling this
6.5% by weight of C9 dinitrile having a purity of 99.99% by weight or more was obtained. Using this dinitrile, hydrogenation was performed to diamine. As a result, diamine having a purity of 85.9% by weight was obtained. This product contained 0.1% by weight of mononitrile and 14.0% by weight of dialkylamine as impurities. (3) Sample diamine C The same raw material as in the case of the above-mentioned supplied diamine B (EMEROX1
144) was similarly used for dinitrile conversion, distillation and diamine conversion to obtain a diamine having a purity of 92.2% by weight. This product has a mononitrile content of 0.2 as an impurity.
% By weight, and 7.6% by weight of dialkylamine content. Further, the weight% of water shown below is the weight% with respect to the total amount of the supplied diamine and water. Further, the weight% of the reaction accelerator is the weight% with respect to the total amount of the supplied diamine and water.

Examples 1 to 3 Using the test diamine A, the diamine A, water and sodium hydroxide in the proportions shown in Table 1 were placed in a 4-necked flask equipped with a water cooling tube, and 400 rpm at 100 to 110 ° C. The hydrolysis reaction was carried out under atmospheric pressure with stirring.

[0015]

[Table 1]

The product obtained by the above hydrolysis reaction was subjected to composition analysis by gas chromatography without filtering. The results are shown in Table 2.

[0017]

[Table 2]

As described above, it can be seen that the mononitrile disappears very quickly when the amount of water is 40 wt% or more, but the speed decreases slightly at 25 wt%. The diamine purity is low because the dialkylamine cutting step (filtration or distillation) is omitted.

Examples 4 to 5 Using the test diamine A at the ratios shown in Table 3, diamine A,
Water and sodium hydroxide were charged, and a hydrolysis reaction was carried out in the same manner as in Examples 1 to 3.

[0020]

[Table 3]

The composition of the hydrolysis reaction product was analyzed by gas chromatography without filtering. The results are shown in Table 4.
Shown in.

[0022]

[Table 4]

From the above reaction results, the amount of NaOH was 2 wt.
It can be seen that the mononitrile disappears promptly when the content is more than 0.5% (0.5 times mol / mononitrile). The diamine purity is low because the dialkylamine cutting step (filtration or distillation) is omitted.

Examples 6 to 8 Using the supplied diamine A, the diamine A, water and, if necessary, this alkaline earth metal hydroxide were charged in a pressure resistant reactor at a ratio shown in Table 5, and the mixture was heated at 160 ° C. 1000 rpm
While applying pressure (approx. 5 kg / cm ² · G)
The hydrolysis reaction was carried out.

[0025]

[Table 5]

The composition of the hydrolysis reaction product was analyzed by gas chromatography without filtering. The results are shown in Table 6
Shown in.

[0027]

[Table 6]

As described above, the mononitrile disappears at high temperature (about 140 ° C. or higher) even in the system without addition of the reaction accelerator or the system with addition of the alkaline earth metal hydroxide as the reaction accelerator. I understand. The diamine purity is low because the dialkylamine cutting step (filtration or distillation) is omitted.

Examples 9 to 10 Diamine B, water and sodium hydroxide were charged in the proportions shown in Table 7 using the test diamine B, and the hydrolysis reaction was carried out in the same manner as in Examples 1 to 3. The composition of the hydrolysis product was analyzed by gas chromatography without filtering, and the results are shown in Table 8.

[0030]

[Table 7]

[0031]

[Table 8]

The hydrolyzed products were filtered at 30 ° C. (Example 9) and 60 ° C. (Example 10) using a filter paper and a filter aid (Celite), respectively, and the composition was analyzed by gas chromatography. The results are shown in Table 9.

[0033]

[Table 9]

As described above, it is understood that the dialkylamine can be completely removed by filtering the hydrolysis product, and the purity of the diamine is improved to 99.9% or more.

Examples 11 to 12 Using the test diamine C, the diamine, water and sodium hydroxide were charged in the proportions shown in Table 10, and the hydrolysis reaction was carried out in the same manner as in Examples 1 to 3. The composition of the hydrolysis product was analyzed by gas chromatography without filtering. The results are shown in Table 11.

[0036]

[Table 10]

[0037]

[Table 11]

The hydrolyzed products were filtered at 30 ° C. (Example 11) and 50 ° C. (Example 12) using a filter paper and a filter aid (Celite), respectively, and the composition was analyzed by gas chromatography. The results are shown in Table 12.

[0039]

[Table 12]

As described above, it is understood that the dialkylamine can be completely removed by filtration, and the diamine purity can be improved to 99.9% or more.

Example 13 The hydrolysis product having the composition shown in Table 8 obtained in Example 9 was distilled and the composition was analyzed by gas chromatography. The results are shown in Table 13.

[0042]

[Table 13]

As described above, it can be understood that the dialkylamine can be completely removed by distillation, and the diamine purity can be improved to 99.9% or more.

Example 14 The hydrolysis products shown in Table 8 obtained in Example 9 were distilled and the composition was analyzed by gas chromatography. The results are shown in Table 14.

[0045]

[Table 14]

As described above, it can be seen that the dialkylamine can be completely removed by filtering and distilling, and the purity of the diamine can be improved to 99.9% or more.

Comparative Example 1 The same raw material as in the case of the test diamine B (EMEROX114
Using 4), dinitration, distillation and diamine conversion were carried out in the same manner to obtain a diamine having a purity of 89.9% by weight. This product contained 0.1% by weight of mononitrile and 10.0% by weight of dialkylamine as impurities. This was distilled to obtain a diamine with a yield of 66.4% by weight. Table 15 shows the composition analysis results by the gas chromatograph.

[0048]

[Table 15]

As described above, even if the amount of mononitrile is considerably reduced in the diamine-forming reaction for a long time, if the hydrolysis treatment is not carried out, the diamine and the mononitrile may be separated at the time of distillation while sacrificing the yield. However, the purity of 99.9% by weight or more generally required as a polymer raw material cannot be achieved.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takeo Inagaki 1-3-7 Main Office, Sumida-ku, Tokyo Inside Lion Corporation

Claims (2)

[Claims] 1. An aliphatic diamine containing at least mononitrile and / or monoamide as an impurity obtained by hydrogenation of an aliphatic dinitrile is hydrolyzed in the presence of water to convert the mononitrile and / or monoamide into a carboxylic acid. A method for producing a high-purity aliphatic diamine, which comprises converting an acid to an acid and then separating and recovering the aliphatic diamine from the obtained hydrolysis product. 2. The hydrolysis treatment is carried out in the presence of an alkali metal hydroxide or an alkaline earth metal hydroxide.
the method of.