JPH06330020A - Chelating composition, its production and detergent composition - Google Patents

Abstract

PURPOSE:To provide a chelating composition containing a specified ratio of an iminodisuccinic acid salt and a hydroxyiminodisuccinic acid salt and useful as an organic chelating agent, a builder for a detergent or an anti-scaling agent. CONSTITUTION:The chelating composition is produced by (A) reacting a maleic acid compound selected from maleic acid, its ammonium salt and maleic acid anhydride with ammonia in an aqueous medium, then (B) adding an alkali metal hydroxide and an alkaline earth metal hydroxide to the reaction solution for salt interchange reaction, (C) controlling the amount of free ammonia in the reaction mixture to <=210mol% based on the maleic acid compound used in the process (A) and subsequently adding and reacting one or more kinds of compounds selected from epoxysuccinic acid, an alkali metal salt and an alkaline earth metal salt therewith and contains an iminodisuccinic acid salt and a hydroxyiminodisuccinic acid in a ratio of iminodisuccinic acid salt : hydroxyiminodisuccinic acid salt =5 to 40:95 to 60 (on weight base).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel chelating composition and a process for producing the same, and more particularly, to an organic chelating agent for detergents containing a specific ratio of iminodisuccinate and hydroxyiminodisuccinate. A chelating composition useful as a builder, a scale inhibitor, a dye improving agent, a plating aid, a peroxide stabilizer, an oil stabilizer, a pigment dispersant for papermaking, etc., and a process for producing the same, and further the chelating composition The present invention relates to a novel detergent composition obtained by blending the above with a surfactant.

[0002]

2. Description of the Related Art Iminodisuccinate (hereinafter referred to as IDS salt) is known, and it has been confirmed that its chelating ability is 250 to 300 mg CaCO ₃ / g IDS as a sodium salt. However, no clear knowledge has been obtained regarding biodegradability. On the other hand, hydroxyiminodisuccinate (sodium salt etc .: hereinafter referred to as HIDS salt) is known, and it has been confirmed that its chelating ability is about 320 mgCaCO ₃ / gHIDS as sodium salt. It is also known that the biodegradability of the one produced from L-aspartic acid is about 80 to 89%.

Looking at their manufacturing methods, HID
S is for International Patent No. 92/02489 and Japanese Patent Laid-Open No. 45-56.
It has been confirmed that it can be produced by the reaction of aspartic acid and epoxysuccinic acid, as seen in Japanese Patent No. 918. In this case, it is necessary to use high-purity aspartic acid in order to obtain HIDS in good yield, but aspartic acid can be used as maleic anhydride, maleic acid or maleic anhydride, as disclosed in JP-A-48-56618. Fumaric acid and ammonia are reacted in the presence of an alkali metal,
Alternatively, after the reaction, alkali metal treatment is performed, and then aspartic acid that precipitates by acid precipitation is separated, and then the mother liquor is recycled to the reaction system, and the IDS that is a byproduct is further reacted with ammonia to be converted to aspartic acid. A complicated method must be adopted.

That is, in the production of HIDS, high-purity aspartic acid is produced in advance by the reaction of maleic acid or the like with ammonia, or expensive natural L-aspartic acid is used, and these are reacted with epoxysuccinic acid. Since the complicated process of making it necessary must be performed, the unit price of the product must be very expensive.

On the other hand, IDS usually uses NH ₃ and maleic acid in a molar ratio of 1: 1.5 to 2.5, and 60 to 1
Although it is produced by reacting at a temperature of 55 ° C., the yield by the reaction is at most about 79%, and a complicated and inefficient purification operation is indispensable for obtaining a highly pure product.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to inexpensively and stably exhibit excellent chelating performance and biodegradability. It is intended to provide such a chelating composition, a method capable of producing such a chelating composition efficiently and inexpensively on an industrial scale, and a detergent composition using the chelating composition. To do.

[0007]

The constitution of the chelating composition according to the present invention which has been able to solve the above-mentioned problems is ID
1 to 99 parts by weight of the S salt and HIDS salt: 99 to 1 parts by weight of the latter, preferably 3 to 90 parts by weight of the former: 95 to 10 parts by weight of the latter, more preferably 5 to 40 parts by weight of the former: the latter. 95-60
The gist is that it is contained in the range of parts by weight.

As the IDS salt and the HIDS salt,
Alkali metal salts, ethanolamine salts, diethanolamine salts, most preferably one or more salts selected from the group consisting of triethanolamine salts, the above chelating composition, the following reaction steps (1) ~ (3) Can be obtained by sequentially performing.

(1) reacting a maleic acid compound selected from the group consisting of maleic acid, its ammonium salt and maleic anhydride with ammonia in an aqueous medium, (2) then adding an alkali metal and And / or adding a hydroxide of an alkaline earth metal for salt exchange, (3) after salt exchange, the amount of free ammonia in the reaction mixture is 10 mol based on the maleic acid compound used in step (1). % Or less, and then a step of adding one or more selected from the group consisting of epoxysuccinic acid, its alkali metal salts and alkaline earth metal salts, and reacting.

The above reaction steps (1) to (3) can be efficiently carried out under the following conditions. (1) The molar ratio of maleic acid compound and ammonia is 1: 1.5.
˜1: 20, the reaction temperature is 90 to 180 ° C., and (2) the addition amount of the alkali metal and / or alkaline earth metal hydroxide is 1 mol of the maleic acid compound used in the above step (1). 0.9 to 1.5 mol, a reaction temperature of 90 to 160 ° C., and (3) an addition amount of one or more selected from the group consisting of epoxysuccinic acid, its alkali metal salts and alkaline earth metal salts,
30-15 based on the aspartic acid produced in step (1) above.
0 mol%, reaction temperature 80-120 ° C.

At this time, if the oxygen concentration in the gas phase of the reaction system in step (1) is suppressed to 5% by weight or less, the reaction solution is prevented from being colored and an uncolored product can be obtained. In the step (3), epoxysuccinic acid to be reacted and / or an alkali metal salt of epoxysuccinic acid and / or
Alternatively, as an alkaline earth metal salt, an aqueous slurry and / or aqueous solution of cis-epoxysuccinic acid and / or its alkali metal salt and / or alkaline earth metal salt produced from maleic acid and hydrogen peroxide in an aqueous medium is used. If the amount of residual hydrogen peroxide is 3% by weight or less based on cis-epoxysuccinic acid and / or its alkali metal salt and / or alkaline earth metal salt,
Coloring of the reaction liquid in the step (3) is prevented, and an uncolored product having a high commercial value can be obtained.

The above chelating composition is used as a builder, and is selected from the group consisting of 1 to 40% by weight, an anionic surfactant, a cationic surfactant and a nonionic surfactant. Detergent surfactant 1
The one containing 40% by weight is a very excellent detergent.

[0013]

The chelating composition according to the present invention is characterized in that the IDS salt and the HIDS salt are mixed in a specific ratio as described above. That is, the IDS salt and the HIDS salt each have the advantages and disadvantages as described above in terms of chelating performance, economical efficiency and the like, but according to various studies conducted by the present inventors, these two kinds are suitable. It has been found that when they are mixed in a ratio, synergistically excellent chelating performance and biodegradability are exhibited, and as a result, a composition that is economically inexpensive and has significantly excellent chelating performance and biodegradability is obtained. And in order to effectively demonstrate such performance, IDS salt and H
1 to 99:99 to 1 part by weight of IDS salt, preferably 3 to
90:97 to 10 parts by weight, more preferably 5 to 40: 9.
It has been found that it may be added at a ratio of 5 to 60 parts by weight.

By the way, FIG. 1 shows the results of investigating the Ca ion chelating ability of various combinations of the IDS salt and the HIDS salt.
The results of examining the biodegradability of a mixture of salt with various ratios (see Experimental Examples below for experimental conditions) are shown. When these two salts are used in combination, the individual salts are used alone. It can be confirmed that synergistically superior chelating performance and biodegradability are exhibited as compared with the case where they are used.

The types of salts that compose these IDS salts and HIDS salts vary depending on the intended use, and therefore should not be understood in a restrictive manner, but the most versatile ones are water-soluble inorganic metal salts and organic salts. Of these, particularly preferable are alkali metal salts such as Na and K, and ethanolamine salts, diethanolamine salts, and triethanolamine salts. The salt may be a single salt or a mixed salt of two or more kinds.

The blends of these IDS salt and HIDS salt have excellent chelating ability. They are used as an organic chelating agent, a detergent builder, a scale preventive, as a powder in a dry state or as an aqueous solution having an arbitrary concentration. Agent, dye improver,
It can be widely used as a plating aid, a peroxide stabilizer, a pigment dispersant for papermaking, and the like.

Among the above-mentioned uses, the use in which the characteristics of the chelating composition according to the present invention are more effectively exerted is the use as a builder for detergents. When used in combination with, it exhibits excellent performance as a detergent composition. In this case, the preferred content of the chelating composition in the detergent is 1 to 4
0% by weight, more preferably 3 to 25% by weight, and the content of the detergent surfactant is preferably 1 to 40% by weight, more preferably 10 to 30% by weight. If the content of the chelating composition is less than 1% by weight, the chelating performance as a detergent builder will not be sufficiently exhibited, while if it exceeds 40% by weight, no further addition effect will be exhibited and it is economically wasteful. .

There is no particular limitation on the kind of the surfactant for detergent used here, and alkyl sulphate, alkyl benzene sulphate, alkyl benzene sulphonate, olefin sulphonate, alkoxylated alcohol, alkyl phenol, alkyl phenol sulphate, fatty acid sulphonate. It is possible to use various conventionally known anionic surfactants, nonionic surfactants, and cationic surfactants such as fatty acid ester sulfonates, etc., which can be used individually and are also required. It is of course possible to use two or more types in combination depending on the requirements.

The detergent composition according to the present invention may include, in addition to the chelating composition and the surfactant, a well-known cleaning auxiliary agent, if desired, for example, a builder compound such as zeolite other than the above-mentioned detergent builder of the present invention, Enzymes such as protease,
It is also possible to add an appropriate amount of a bleaching agent such as perborate or a bleaching auxiliary agent, an antifouling agent, a suspending agent, a fabric softening agent and the like.

By the way, the above chelating composition is
S salt and HIDS salt are mixed in a predetermined ratio, or IDS
It is also possible to obtain it by neutralizing a mixture of HIDS and HIDS with an appropriate salt, but if the following production method is adopted, a chelating composition comprising the above mixed salt can be efficiently obtained in a simple process. it can.

The production method is (1) a first step of reacting a maleic acid compound selected from the group consisting of maleic acid, its ammonium salt and maleic anhydride with ammonia in an aqueous medium, (2) A second step of adding a hydroxide of an alkali metal and / or an alkaline earth metal to the reaction solution for salt exchange, (3) after the salt exchange, the amount of free ammonia in the reaction mixture is used in the step (1). After adjusting the amount of the maleic acid compound to 10 mol% or less, a third step of sequentially reacting with one or more selected from the group consisting of epoxysuccinic acid, its alkali metal salt and alkaline earth metal salt, The method is carried out, the above step (1),
The preferred conditions of (2) and (3) are as follows.

First step (1): The molar ratio of maleic acid compound to ammonia is 1: 1.5 to 1:20 and the reaction temperature is 90 to 18
0 ° C., Second step (2): Addition amount of hydroxide of alkali metal and / or alkaline earth metal is 0.9 to 1.5 moles per 1 mole of maleic acid compound used in the above step (1), The temperature is 90 to 160 ° C., the third step (3): one or more addition amounts selected from the group consisting of epoxysuccinic acid, its alkali metal salts and alkaline earth metal salts, are produced in the above step (1). 30-150 mol% relative to aspartic acid, reaction temperature 50-120 ° C.

The above method will be described in more detail. Step (1): In this step, a maleic acid compound selected from the group consisting of maleic acid, its ammonium salt and maleic anhydride, and a 1.5 to 20-fold molar amount thereof, preferably 1.8 to 15-fold molar amount thereof. The reaction of producing aspartate and IDS salt is carried out by reacting the same with ammonia in an aqueous medium. At this time, when the amount of ammonia with respect to the maleic acid compound is less than 1.5 times the molar amount, the charged maleic acid compound does not sufficiently react, and as a result, the IDS salt formation reaction does not proceed sufficiently and the final target product Yield and purity do not rise sufficiently,
On the other hand, even if a large amount of ammonia in excess of 20 times mol is used, further improvement in yield cannot be expected, which is economically wasteful.

The preferred reaction temperature at this time is 90 to 1
80 ° C., more preferably 95 to 150 ° C. If the reaction temperature is lower than 90 ° C., the reaction rate becomes extremely slow, and industrial practicality is lost in terms of productivity, while if the temperature exceeds 180 ° C. However, the reaction rate does not increase any further, not only the heat source for heating is consumed unnecessarily, but also 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 it is usually
It is carried out for 0.1 to 20 hours, preferably for 0.2 to 10 hours. In this reaction step, an undesired oxidation reaction can be suppressed by suppressing the oxygen concentration in the gas phase of the reaction system to 5% by weight or less, whereby coloring of the reaction liquid can be prevented, which is preferable.

Step (2): After the step (1), an alkali metal hydroxide and / or an alkaline earth metal hydroxide is added to the reaction solution to form an alkali metal salt and / or an alkaline earth metal salt. . At this time, the amount of the hydroxide to be added is preferably in the range of 0.9 to 1.5 mol, based on 1 mol of the maleic acid compound used in the first step (1), and 0.9
If it is less than the molar amount, the rate of salt exchange will be slow and the efficiency will be poor. On the other hand, if it exceeds 1.5 mol, the fumarization of maleic acid will be facilitated by the hydroxide present in excess, so that the objective The product yield cannot be increased sufficiently.

The preferable temperature at this time is 90 to 160.
℃, more preferably 100 ~ 130 ℃, 90 ℃
If the temperature is lower than below, it takes a long time for salt exchange, which is not suitable for actual operation. Further, even if the temperature is higher than 160 ° C., no further effect of promoting salt exchange can be expected, side reactions are likely to occur, and the reaction liquid is likely to be colored, which is an adverse effect. The treatment time varies depending on the amount of hydroxide added and the conditions for recovering ammonia, etc., but is usually 10 minutes to 10 hours.

Step (3): In this step, the amount of ammonia in the reaction solution after the above step (2) is adjusted to 10 mol% or less based on the maleic acid compound used in step (1),
One or more epoxysuccinic acid compounds selected from the group consisting of epoxysuccinic acid, its alkali metal salts and alkaline earth metal salts are added and reacted. At this time, if the amount of ammonia when the epoxysuccinic acid compound is added exceeds 10 mol% with respect to the initial maleic acid compound, a side reaction product is generated by the reaction between the ammonia in the reaction solution and the epoxysuccinic acid compound, and The purity of the product decreases. Therefore,
It is an essential requirement that the amount of ammonia in the reaction solution is adjusted to 10 mol% or less, more preferably 7 mol% or less, based on the initial maleic acid compound.

Next, an epoxysuccinic acid compound is added to this solution and reacted to form a hydroxyiminodisuccinate. At this time, the epoxysuccinic acid compound does not react with the IDS salt that has already been formed, but selectively reacts only with the aspartic acid formed in step (1), so the obtained reaction product is the IDS salt. It is obtained as containing HIDS salt. That is, both IDS and aspartic acid have active hydrogen, and it is considered that both of them have the ability to react with epoxysuccinic acid. However, according to the confirmation by the present inventors, the epoxy added in this step is confirmed. It was confirmed that succinic acid does not react with IDS but selectively reacts only with aspartic acid to form a HIDS salt.

In other words, in the present invention, this selective reactivity is effectively utilized, the IDS produced in the steps (1) and (2) is left as it is, and only the by-product aspartic acid is changed to epoxysuccinic acid. HID by reacting
Change to S, ID without special refining operation
It is characterized in that a highly pure reaction product of the S salt and the HIDS salt is obtained.

The amount of the epoxysuccinic acid compound added is 30 to 30 parts with respect to the aspartic acid produced in the first step (1).
It is preferable to set it in the range of 150 mol%, more preferably 80 to 110 mol%. If it is less than 30 mol%, the reaction rate for forming the HIDS salt is slow, while if it exceeds 150 mol%, the HID
The rate of the S salt formation reaction does not increase any more, and a large amount of impurities are generated to lower the product purity, which is economically wasteful.
The reaction temperature is not particularly limited, but it is preferably in the range of 50 to 120 ° C, and more preferably 60 to 90 ° C in order to efficiently proceed the HIDS salt-forming reaction without causing side reactions.

In this step (3), as the added alkali metal salt and / or alkaline earth metal salt of epoxysuccinic acid and / or epoxysuccinic acid, it was prepared from maleic acid and hydrogen peroxide in an aqueous medium. Aqueous slurry of cis-epoxysuccinic acid and / or its alkali metal salt and / or alkaline earth metal salt and / or
Alternatively, using an aqueous solution, the residual hydrogen peroxide is cis-
By adjusting the amount of the epoxy succinic acid and / or its alkali metal salt and / or alkaline earth metal salt to 3% by weight or less, coloring of the reaction solution is prevented, side reactions during the reaction are suppressed, and the IDS salt and It is preferable because a reaction product having a higher HIDS salt purity can be obtained.

In carrying out the above steps (1) to (3),
In particular, the reaction conditions in step (1) are adjusted to adjust the ratio of the aspartic acid compound and the IDS compound produced, and the amount of epoxysuccinic acid compound added in step (3) and the reaction conditions are adjusted to produce HIDS salt. By controlling the amounts, a mixture containing the IDS salt and the HIDS salt in an arbitrary ratio can be obtained. These salts may be used as a chelating composition as they are, or may be salt-exchanged with a more preferable salt if necessary.

These reactions may be carried out in the same reaction vessel through steps (1) to (3) or may be carried out in different reaction vessels, and may be carried out batchwise or continuously. Does not ask.

IDS salt and H produced by the above three steps
The IDS salt may be provided as a chelating composition as an aqueous solution, or may be dried as necessary and supplied as a powder. If necessary, it is of course possible to carry out a purification treatment by a known method.

[0036]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples, and can be appropriately modified within the range that can meet the gist of the preceding and following description. Of course, it is also possible to add
All of them are included in the technical scope of the present invention.

Example 1 Individually synthesized and purified HIDS and IDS (both having a purity of 98%) were used in the ratios shown in Table 1, and Ca was prepared by the following method.
The ion chelating ability and biodegradability and the detergency as a detergent were examined, and the results shown in Table 1 were obtained.

<Ca ion chelating ability> In a 100 ml beaker, 10 mg of a sample chelating composition (a mixture of HIDS and IDS) was precisely weighed and dissolved in 50 ml of 1.0 × 10 ⁻³ mol of calcium chloride aqueous solution. Further 4.0
After adjusting the ionic strength with 1 ml of a 1 molar aqueous solution of potassium chloride, the solution pH was adjusted to 11 with a 1 molar aqueous solution of potassium hydroxide.
Adjusted to. The residual Ca ion concentration was measured using an ion electrode (“Mode 193-20” manufactured by Orion Co., Ltd.) while stirring this in a thermostat at 20 ° C. The measurement result is CaC chelated by 1 g of the sample chelating composition.
It was shown in mg of O ₃ .

<Biodegradability test> Using the mixture of HIDS and IDS having various compounding ratios obtained in the same manner as above, OE was used.
Modification of CD test guideline The biodegradability was examined by changing the method by the MITI test as follows. Basic culture solution: Compliant with modified MITI test (I) Activated sludge: Activated sludge from sewage treatment plant Culture method: Shinto culture method Test conditions: ・ Test substance concentration 15ppm ・ Activated sludge concentration 50ppm ・ Test temperature 25 ± 1 ℃ ・ Test Period 28 days Evaluation: Based on measurement of TOC (total organic carbon content in solution). Degradation was calculated according to the following formula. Degradation rate (%) = [(C ₀ −C ₀₁ ) − (C _t −C _t−1 ) /
C ₀ −C ₀₁ ] × 100 C ₀ : TOC in test solution at start of test C ₀₁ : TOC C _t in blank test solution at start of test: TOC C _{t1 in} test solution t days after start of test: TOC in blank test solution t days after the start of the test

<Detergency Test as Detergent> A chelating composition having each compounding ratio was used as a builder, and a linear alkylbenzene sulfonic acid sodium salt (hereinafter referred to as LAS) was used as a surfactant. The detergent composition shown in 1 was prepared, and the detergency was examined under the following conditions using an artificial cotton cloth. Cleaning conditions Tester: Targotometer Concentration of cleaning liquid: 0.12% by weight Water hardness: 3 degrees DH Bath ratio: 4 contaminated cloths 1 L Cleaning temperature: 25 ° C Rotation speed: 200 times / minute Cleaning time: 10 minutes Rinsing: 5 minutes once Detergency: The surface reflectance of the cloth before and after washing was measured, the detergency obtained by the following formula was determined, and the detergency when zeolite was used as the builder compound was evaluated as an index. . Detergency = [(Reflectance of cloth after washing-Reflectance of cloth before washing) / (Reflectance of original cloth-Reflectance of cloth before washing)]

[0041]

[Table 1]

[0042]

[Table 2]

Example 2 116 g (1.0 mol) of maleic acid was mixed with 135 g of water, and to this was added 136 g (2.0 mol) of 25% by weight aqueous ammonia. The reaction solution is autoclaved at 140 ℃
At room temperature for 2 hours, then 167 g (2.0 mol) of 48% by weight aqueous sodium hydroxide solution was added,
The reaction was carried out at 0 ° C for 1 hour. After completion of the reaction, dissolved NH ₃ in the reaction solution was adjusted to 1.1 mol% with respect to the initially charged maleic acid by blowing nitrogen gas.

Separately from the above reaction solution, 280 g of an aqueous solution containing 97 g (0.55 mol) of cis-epoxysuccinic acid disodium salt prepared from maleic acid and hydrogen peroxide was mixed with the above reaction solution, and the mixture was mixed at 80 ° C. for 4 hours. Reacted for hours. As a result of analyzing the reaction solution after the reaction by high performance liquid chromatography, the purity as a HIDS / IDS mixed composition was 92.6% by weight to the total organic acid salt, and the composition ratio of HIDS and IDS was about 73:27 ( Weight ratio).

In accordance with the above method, the amounts of raw materials used, the reaction conditions, etc. were changed as shown in Table 3 in the same manner as described above.
A chelating composition comprising an IDS mixed salt was produced. The results are shown in Table 4 together with the Ca ion chelating ability, biodegradability and detergency of each composition. In the detergency test, the dry powder of each composition produced above was used, the composition of the detergent was as shown in Table 5, and the detergency was evaluated in the same manner as in Example 1.

As is clear from these results, in Examples A to M satisfying the requirements of the present invention, a mixture of high-purity IDS salt and HIDS salt was obtained,
It can be seen that their Ca ion chelating ability, biodegradability and detergency are all excellent. On the other hand, Comparative Examples N to Q lacking the requirements of the present invention are all low in purity and inferior in Ca ion chelating ability, biodegradability and detergency. In Reference Examples R and S, the oxygen concentration in the gas phase in the step (1) exceeds the preferable range, and in Reference Example T, the residual hydrogen peroxide amount in the step (3) exceeds the preferable range. In each case, the product purity itself is considerably high, but the product is markedly colored.

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

[Table 5]

The chelating composition of the present invention obtained by this method can be effectively used as a detergent composition as described above, but in addition to this, alone or with an optional auxiliary additive or the like. In combination, for example, scale inhibitor,
Dye improver, plating aid, peroxide stabilizer, oil stabilizer,
It can be widely used as a pigment dispersant for papermaking.

[0051]

The present invention is constituted as described above, and by containing iminodisuccinate and hydroxyiminodisuccinate in a specific ratio, an organic chelating agent, a builder for detergents, a scale inhibitor and a dye. A chelating composition useful as an improver, a plating aid, a peroxide stabilizer, an oil stabilizer, a pigment dispersant for papermaking, etc. can be provided, and the composition can be produced economically and inexpensively and efficiently. Furthermore, it has become possible to provide a detergent composition having excellent performance.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the content of IDS salt in IDS salt / HIDS salt and the chelating ability.

FIG. 2 is a graph showing the relationship between the content of IDS salt in IDS salt / HIDS salt and biodegradability.

Claims (5)

[Claims] 1. A chelating composition comprising an iminodisuccinate and a hydroxyiminosuccinate in a ratio of 1 to 99 parts by weight of the former and 99 to 1 parts by weight of the latter. 2. The following reaction steps (1) to (3) are sequentially carried out,
A process for producing a chelating composition, characterized in that a mixture containing iminodisuccinate and hydroxyiminosuccinate in a ratio of 1 to 99 parts by weight of the former and 99 to 1 parts by weight of the latter is obtained. (1) reacting a maleic acid compound selected from the group consisting of maleic acid, its ammonium salt and maleic anhydride with ammonia in an aqueous medium, (2) then adding an alkali metal and / or alkali to the reaction solution A step of adding a hydroxide of an earth metal to perform salt exchange, (3) after salt exchange, the amount of free ammonia in the reaction mixture is
10 mol% based on the maleic acid compound used in step (1)
After adjusting to the following, a step of adding and reacting one or more of epoxysuccinic acid, its alkali metal salt and alkaline earth metal salt. 3. The method according to claim 2, wherein in the step (1), the oxygen concentration in the gas phase of the reaction system is set to 5% by weight or less to prevent coloration of the reaction solution. 4. In the step (3), as the alkali metal salt and / or alkaline earth metal salt of epoxysuccinic acid and / or epoxysuccinic acid to be reacted, it is prepared from maleic acid and hydrogen peroxide in an aqueous medium. cis-
An aqueous slurry and / or aqueous solution of epoxysuccinic acid and / or its alkali metal salt and / or alkaline earth metal salt is used to remove residual hydrogen peroxide.
-Coloring of the reaction liquid is prevented by controlling the content of epoxysuccinic acid and / or its alkali metal salt and / or alkaline earth metal salt to 3% by weight or less.
Or the method described in 3. 5. A detergent composition comprising the chelating composition according to claim 1 as a builder.