JP3326867B2 - Method for producing metal salt of iminodisuccinic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal salt of iminodisuccinic acid, and more particularly, to an organic chelating agent, a builder for a detergent, a scale inhibitor, a dye improver, a plating aid, a peroxide stabilizer. The present invention relates to a method for efficiently producing an alkali metal salt and / or alkaline earth metal salt of iminodisuccinic acid, which is useful as an agent, an oil stabilizer, a pigment dispersant for papermaking, etc., by reacting a maleic acid compound with ammonia.

[0002]

2. Description of the Related Art It has long been known that metal salts of iminodisuccinic acid have a high chelating power, and according to the knowledge of the present inventors, compounds which are very useful as soaps and detergent builders. Make sure that

[0003] As a method for producing a metal salt of iminodisuccinic acid, various methods are disclosed in various documents, such as a production method by reacting maleic acid with ammonia. For example, UK Patent No. 1,
No. 306,331 discloses maleic acid and ammonia:
Used in a molar ratio of 1.5 to 1: 2.5,
It discloses a method of obtaining a metal salt of iminodisuccinic acid by carrying out a salt exchange after reacting at 155 ° C. fact,
It has been confirmed by the present inventors that the above-mentioned method enables the target metal salt of iminodisuccinic acid to be obtained in a yield of about 70%.

However, the yield of the metal salt of iminodisuccinic acid obtained by this method is at most about 70%. Even if an attempt is made to increase the yield by elongating the reaction time or the like, only the side reaction proceeds, and the iminodisuccinic acid salt is produced. Does not increase any more, and the yield tends to decrease due to the progress of side reactions. In addition, in the reaction solution obtained by the above reaction, aspartic acid and metal fumarate are generated in large amounts as by-products in addition to the desired iminodisuccinic acid, which is an advanced and commercially available product. Complicated purification is required.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to produce a metal salt of iminodisuccinic acid on an industrial scale without causing side reactions as much as possible. An object of the present invention is to provide a method which can be economically produced with high yield and high purity.

[0006]

Means for Solving the Problems The constitution of the production method according to the present invention, which can solve the above-mentioned problems, comprises maleic acid,
In a method for producing a metal iminodisuccinate by reacting at least one maleic acid compound (A) selected from the group consisting of ammonium maleate and maleic anhydride with ammonia, the following reaction step (1)
(3) is sequentially performed. (1) a step of reacting the maleic acid compound (A) with ammonia in an aqueous medium; (2) Then, an alkali metal hydroxide and / or an alkaline earth metal hydroxide are added, and the alkali metal and / or alkali are added. A step of forming an earth metal salt,
(3) A step of further adding and reacting at least one maleic acid compound (B) selected from the group consisting of maleic acid, maleic acid alkali metal salts and maleic acid alkaline earth metal salts.

In the reaction step (1), it is preferable to react 1.5 to 20 times mol of ammonia with respect to the maleic acid compound (A), and in the reaction step (2), ammonia is added. The amount of the alkali metal hydroxide and / or the alkaline earth metal hydroxide is adjusted with the maleic acid compound (A)
Is preferably 1 equivalent or more. In the reaction step (3), the amount of the maleic acid compound (B) to be added is more than 0 and not more than 1.2 times the molar amount of the maleic acid compound (A). Is 0.9 ~
It is recommended as a more preferable embodiment to add an alkali metal hydroxide and / or an alkaline earth metal hydroxide so as to be 1.2 equivalents.

[0008]

According to the present inventors, various studies have been conducted on a method for producing a metal salt of iminodisuccinic acid using maleic acid and ammonia. According to the method described in the above-mentioned literature, the reaction time is increased as described above. As the reaction proceeds, the side reaction easily proceeds, the amount of by-products of aspartic acid and metal fumarate increases, and the yield as a metal salt of iminodisuccinic acid not only decreases, but also the processing efficiency for purification deteriorates . Under such circumstances, it is considered that the progress of the side reaction is suppressed by suppressing the yield of the target compound to a low level even in the method disclosed in the above literature.

However, the present inventors have conducted further studies, and have found that after using a maleic acid compound and ammonia to carry out the reaction to some extent in the form of ammonium maleate, the reaction is carried out with an alkali metal and / or alkaline earth metal. It was found that if the salt was exchanged with a metal salt and then the maleic acid compound was further added to proceed with the reaction, the production reaction of the metal salt of iminodisuccinic acid proceeded more selectively. It has been completed.

As the maleic acid compound (A) used as a starting material in the reaction step (1) of the present invention, maleic acid, its ammonium salt or maleic anhydride is used, and these may be used alone. May be used in combination of two or more. At this time, if a metal salt of maleic acid or maleic anhydride is used, the reaction for producing iminodisuccinic acid hardly proceeds, and the purpose cannot be achieved.

The maleic acid compound (B) used in the reaction step (3) includes maleic acid, an alkali metal salt of maleic acid, and an alkaline earth metal salt of maleic acid. More than one species may be used in combination. However, if an ammonium salt of maleic acid is used at this time, a side reaction proceeds in this reaction step (3), so that not only the yield as a metal salt of iminodisuccinic acid cannot be increased but also the purity decreases.

The above maleic compounds (A) and (B) are used for the reaction in an aqueous medium, and may be added in any form of solid, slurry, aqueous solution, etc., and maleic anhydride is used. In this case, it can be added in a solid or molten state. Ammonia used for the reaction may be in the form of an aqueous solution or gas, or both may be used in combination. In the final stage of the reaction step (2), it is preferable to remove ammonia.
This ammonia can be recovered and reused by existing methods. Hereinafter, the method of the present invention will be described in more detail.

Reaction step (1): In this step, a maleic acid compound (A) and 1.5 to 20 times, preferably 1.8 to 15 times, its molar amount of ammonia are used, and an aqueous medium is used. The reaction is carried out in a mixed state. At this time, the amount of ammonia relative to the maleic acid compound (A) is 1.5
If the molar ratio is less than twice, the charged maleic acid does not sufficiently react, and as a result, the yield and purity of the target product after the final reaction is not sufficiently increased. On the other hand, even if a large amount of ammonia exceeding 20 times the molar amount is used, no further improvement in yield can be expected, which is economically disadvantageous.

The preferred reaction temperature at this time is 90 to 1
When the reaction temperature is lower than 90 ° C., the reaction rate becomes extremely slow and lacks industrial practicality in terms of productivity. This does not mean that the reaction rate is further increased, not only that the heat source for heating is unnecessarily consumed, but also that side reactions easily occur. In order to further increase the reaction rate in this temperature range, it is also effective to concentrate the reaction solution before or during the reaction. The reaction time varies depending on the reaction temperature, the concentration of the reaction system and the amount of ammonia used, but is usually 0.1 to 20 hours, preferably 0.1 to 20 hours.
It is performed in the range of 2 to 10 hours.

Reaction step (2): After the above-mentioned reaction step (1), an alkali metal hydroxide and / or an alkaline earth metal hydroxide are added to the reaction solution, and an alkali metal and / or alkaline earth metal salt is added. I do. At this time, after the reaction of the maleic acid compound with ammonia, 1 equivalent or more, preferably 1.0 equivalent or more, based on the maleic acid compound (A) used at the start of the reaction.
It is preferable to add 0 to 1.2 equivalents of an alkali metal hydroxide and / or an alkaline earth metal hydroxide (hereinafter, sometimes referred to as an added hydroxide) to react.

If the amount of the added hydroxide is less than 1 equivalent, the rate of salt exchange becomes slow and the efficiency becomes poor, and a side reaction is liable to occur in the next reaction step (3). As a result, various amidates are produced, and the yield and purity of the target product tend to be reduced. On the other hand, if it exceeds 1.2 equivalents, the fumalization of maleic acid (change to fumaric acid) in the reaction step (3) is apt to proceed in the reaction step (3) due to an excess of hydroxide, and the yield of the target product is also sufficiently increased. Disappears.

The preferred processing temperature at this time is 50 to 1
80 ° C., more preferably 80 to 130 ° C .;
If the temperature is lower than ℃, the salt exchange takes a long time and is not suitable for actual operation. Further, even if the temperature is higher than 180 ° C., no further effect of promoting salt exchange can be expected, and adverse effects such as side reactions are likely to occur and the reaction solution is likely to be colored.

At this time, it is also effective to remove ammonia remaining in the reaction system, and it is preferable to remove ammonia by bubbling gas such as air or nitrogen under reduced pressure, increased pressure or normal pressure. . The treatment time varies depending on the amount of the added hydroxide or the condition for recovering ammonia, but is usually in the range of 10 minutes to 10 hours.

Reaction step (3): In this step, the reaction solution after the reaction step (2) is added in an amount of preferably 0.1 to 1.2 times mol of the maleic acid compound (A) at the start of the reaction.
More preferably, the reaction is carried out by adding 0.1 to 0.9 times mol of the maleic acid compound (B) and continuing the reaction. That is, the maleic acid compound (B) added here
The amount of is preferably determined by the conversion of the maleic acid compound in the reaction step (1). When the amount of the maleic acid compound (B) added in this step exceeds 1.2 moles, the amount of maleic acid decreases. Not only remains unreacted, but also fumaration tends to proceed, and the purity of the target product tends to decrease.

In the reaction step (3), an alkali metal hydroxide and / or an alkaline earth metal hydroxide are added, and the degree of neutralization of the total acid content of the reaction system is 0.90 to 1.2 equivalents. ,
It is preferably adjusted to 0.95 to 1.1 equivalents, thereby increasing the reaction rate and further suppressing the progress of side reactions. When the degree of neutralization is less than 0.90 equivalent, the progress of the reaction is slow, and when the degree of neutralization exceeds 1.2 equivalents, the reaction of forming by-products easily proceeds due to the presence of excess hydroxide. Become.

When the maleic acid compound (B) is added, only the maleic acid compound (B) may be simply added. However, in order to further increase the reaction rate, the removal of excess ammonia is carried out simultaneously. Or after removal,
It is also effective to concentrate the reaction solution to increase its concentration.
Further, the reaction may be performed after or while the reaction solution is concentrated in the same manner as in the reaction steps (1) and (2). A preferable reaction temperature at this time is 70 to 130 ° C.
At a low temperature of less than 70 ° C., the reaction rate becomes extremely slow. On the other hand, at a high temperature of more than 130 ° C., the yield decreases due to fumaric maleic acid and the reaction solution tends to be colored. The reaction time may be appropriately adjusted depending on the reaction temperature, the concentration of the reaction solution, and the like.
Preferably, it is in the range of 3 to 10 hours.

The gas phase conditions during the reaction are not particularly limited in any of the above reaction steps (1) to (3).
The reaction can be performed under an air or oxygen atmosphere, or under an inert gas atmosphere such as nitrogen or argon. In addition, these reactions may be carried out in the same reaction vessel throughout the reaction steps (1) to (3), or may be carried out in separate reaction vessels. Not something.

The metal iminodisuccinate produced by the above three steps can be supplied as an aqueous solution or, if necessary, dried as a powder. If necessary, it is of course possible to perform a purification treatment by a known method to obtain a highly purified product.

The present invention is constituted as described above. After reacting the maleic acid compound (A) with ammonia, salt exchange is carried out, and the maleic acid compound (B) is further added and reacted. The metal iminodisuccinate can be industrially and efficiently produced in high yield and high purity without purifying by-products.

[0025]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and may be appropriately changed within a range that can conform to the spirit of the preceding and following examples. Of course, it is also possible to implement
All of them are included in the technical scope of the present invention.

EXAMPLE 1 49 g of maleic anhydride was added to 29% by weight of aqueous ammonia 35
It was dissolved in 2 g and reacted at 130 ° C. for 1 hour. To this reaction solution, 167 g of a 48% by weight aqueous sodium hydroxide solution was added, and the mixture was heated and stirred at 100 ° C. for 5 hours while removing and removing residual ammonia by blowing in nitrogen gas, followed by 58 g of maleic acid. Was added and reacted under reflux for 20 hours. After completion of the reaction, the composition of the organic acid sodium salt in the reaction solution was analyzed by high performance liquid chromatography. As a result, the yield of the target sodium salt of iminodisuccinate was 87.5 mol% based on the initially charged maleic acid. Was.

Examples 2 to 6 The reaction was carried out in the same manner as in Example 1 except that the reaction conditions were changed as shown in Table 1, and the results shown in Table 1 were obtained. Comparative Examples 1 to 7 The results shown in Table 1 were obtained in the same manner as in Example 1 except that the reaction conditions were changed as shown in Table 1.

[0028]

[Table 1]

[0029]

The present invention is constituted as described above. After reacting the maleic acid compound (A) with ammonia,
Salt exchange is performed by adding an alkali or alkaline earth metal hydroxide to the system, and then a maleic acid compound (B) is further added and reacted to obtain an alkali or alkaline earth metal iminodisuccinate with high purity. It can be produced industrially and efficiently with high yield.

Continuation of the front page (56) References JP-B-40-25133 (JP, B1) UK Patent 1306331 (GB, B) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 227/06 C07C 229 / 24 CA (STN)

Claims (5)

(57) [Claims] 1. A method for producing a metal iminodisuccinate by reacting at least one maleic acid compound (A) selected from the group consisting of maleic acid, ammonium maleate and maleic anhydride with ammonia, A process for producing a metal salt of iminodisuccinic acid, which comprises sequentially performing the reaction steps (1) to (3). (1) a step of reacting the maleic acid compound (A) with ammonia in an aqueous medium; (2) Then, an alkali metal hydroxide and / or an alkaline earth metal hydroxide are added, and the alkali metal and / or alkali are added. A step of forming an earth metal salt,
(3) a step of adding and reacting at least one maleic acid compound (B) selected from the group consisting of maleic acid, maleic acid alkali metal salts and maleic acid alkaline earth metal salts; 2. The method according to claim 1, wherein in the reaction step (1), 1.5 to 20 times the amount of ammonia is reacted with the maleic acid compound (A). 3. The method according to claim 1, wherein in the reaction step (2), the amount of the alkali metal hydroxide and / or the alkaline earth metal hydroxide to be added is at least 1 equivalent to the maleic acid compound (A). Or the method of 2. 4. The method according to claim 1, wherein in the reaction step (3), the amount of the maleic acid compound (B) added is more than 0 and not more than 1.2 times the molar amount of the maleic acid compound (A). The method described in. 5. In the reaction step (3), an alkali metal hydroxide and / or an alkaline earth metal hydroxide is added, and the degree of neutralization of the total acid content of the reaction system is 0.9 to 1.2 equivalents. The method according to any one of claims 1 to 4, wherein the method is adjusted to: