JPH09124567A - Biodegradable chelating agent containing 2,2'-dimethyliminodiacetic acid derivative and its alkali metal salt and method for producing the same - Google Patents

Abstract

(57) Abstract: A chelating agent comprising dimethyliminodiacetic acid and a dimethyliminodiacetic acid derivative and having excellent biodegradability is provided. The biodegradable chelating agent of the present invention comprises dimethyliminodiacetic acid, 2,2′-dimethylnitrilotriacetic acid,
It contains 2,2'-dimethyl-β-alanine-N, N-diacetic acid and alkali metal salts thereof as components. The biodegradable chelating agents of the present invention, 2,2'-dimethylnitrilotriacetic acid and 2,2'-dimethyl-β-alanine-N, N-diacetic acid, are dimethyliminodiacetic acid, hydrocyanic acid, formaldehyde and glyco It can be produced by reacting ronitrile, acrylonitrile, acrylamide, acrylic acid, halogenated alkylcarboxylic acid and the like.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable chelating agent containing a 2,2′-dimethyliminodiacetic acid derivative and an alkali metal salt thereof, and a method for producing the same. The biodegradable chelating agent of the present invention can be widely used in detergent compositions, detergent builders, sequestering agents, peroxide stabilizers and the like.

[0002]

2. Description of the Related Art Several monomethyl derivatives of iminodiacetic acid have been conventionally known. For example, as a method of producing N-methyliminodiacetic acid, a method of adding two molecules of chloroacetic acid to one molecule of methylamine has been reported (Organi.
c Syntheses, collecitve volume II, pages 397-399)
. Further, as a method for producing 2-methyliminodiacetic acid, α-
A method of adding two molecules of monochloroacetic acid to alanine has been reported (Tetrahedron Letters 1984, 40, 5
72-579). For dimethyliminodiacetic acid, which is a dimethyl derivative of iminodiacetic acid, a method of adding 2-chlorobutyric acid to α-alanine has been reported (Tetr
ahedron Letters, 1984, 40, 572-579).

Similarly, a synthesis method and chelate stability constant of 2,2-dimethylnitrilotriacetic acid have been reported (Ars Pharmaceuteca, 1991, Vol. 22, No. 4 ,.
429-444, Anales De Quimica, 1983, Volume 79, 572-
579). With respect to 2,2′-dimethylnitrilotriacetic acid, which is this positional isomer, a method of adding 2-chlorobutyric acid to α-alanine and then reacting with monochloroacetic acid has been reported (Chemistry Letters, 1974, 993). -996
page).

As described above, regarding dimethyliminodiacetic acid and its derivatives, there are few reports on the synthetic method, and there is no report on biodegradability evaluation and performance evaluation as a chelating agent, and utilization as a biodegradable chelating agent. Has not been considered.

[0005]

The present invention has been made to solve the problems of the prior art, and its object is to utilize dimethyliminodiacetic acid as a biodegradable chelating agent. Another object of the present invention is to provide a stronger biodegradable chelating agent by chemically modifying dimethyliminodiacetic acid. Specifically, 2,2,2 '-Dimethylnitrilotriacetic acid, 2,2'-dimethyl-β-alanine-
It is intended to produce N, N-diacetic acid and alkali metal salts thereof, and utilize them as biodegradable chelating agents.

[0006]

Means for Solving the Problems As a result of intensive research to solve the above-mentioned problems, the present inventors have found that dimethyliminodiacetic acid, hydrocyanic acid and formaldehyde, glycolonitrile,
By reacting acrylonitrile, acrylamide, acrylic acid, halogenated alkylcarboxylic acid, etc., 2,2′-dimethylnitrilotriacetic acid, 2,2′-dimethyl-β-alanine-N, N-diacetic acid and their alkalis We manufacture metal salts, evaluate their biodegradability,
Comparing the Ca ²⁺ scavenging ability, it has a chelating power equivalent to that of conventionally known chelating agents such as iminodiacetic acid, nitrilotriacetic acid, β-alanine-N, N-diacetic acid, and biodegradation. The present invention has been achieved by discovering that the compound has a property.

That is, the first invention of the present invention is characterized by containing at least one of the 2,2'-dimethyliminodiacetic acid derivatives represented by the following general formula [1] as an active ingredient. The main point is degradable chelating agents.

General formula [1] [In the formula, R is a hydrogen atom, -CH ₂ COOX ₃ or -C
H ₂ CH ₂ COOX ₃ is represented, and X ₁ , X ₂ and X ₃ represent a hydrogen atom, Na or K. ]

A second invention of the present invention is the following general formula [2]
2,2'-dimethyliminodiacetic acid represented by the formula or an alkali metal salt thereof is reacted with a compound having a nitrile group, 2,2'-dimethyl represented by the following general formula [3] The gist is a method for producing an iminodiacetic acid derivative and an alkali metal salt thereof.

General formula [2] [In the formula, X ₁ and X ₂ represent a hydrogen atom, Na or K. ]

General formula [3] [Wherein, R -CH ₂ COOX ₃ or -CH ₂ CH ₂
COOX ₃ , wherein X ₁ , X ₂ and X ₃ are hydrogen atoms, Na
Or K is indicated. ]

The third invention of the present invention is the above general formula [2].
The gist is a method for producing the compound of the above-mentioned general formula [3], which comprises reacting the compound of the above with a halogenocarboxylic acid.

A fourth invention of the present invention is the above general formula [2].
The gist is a method for producing a compound of the above-mentioned general formula [3], which comprises reacting the above compound with an unsaturated compound.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The 2'2-dimethyliminodiacetic acid derivative represented by the above general formula [1] and the alkali metal salt thereof in the present invention include 2,2'-dimethylnitrilotriacetic acid and 2,2'-dimethyl- Mention may be made of β-alanine-N, N-diacetic acid and their alkali metal salts.

In the method of the present invention, dimethyliminodiacetic acid used as a raw material may be one synthesized by various methods. For example, Tetrahedron Letters, 40, 572-
579 (1984), synthesized from α-alanine, synthesized by Strecker reaction using 2-fold moles of acetaldehyde and hydrogen cyanide with respect to ammonia, recovered from production waste liquid of α-alanine, etc. Either is fine. It is desirable that the purity of dimethyliminodiacetic acid used is as high as possible, but 70% or higher purity,
The purity is preferably 90% or more.

Examples of the compound having a nitrile group used in the production method of the present invention include hydrocyanic acid, glycolonitrile, acetonitrile and the like. Examples of the halogenocarboxylic acid include 3-chloropropionic acid and 3-bromopropionic acid. As an unsaturated compound,
Examples thereof include acrylonitrile, acrylamide, acrylic acid and the like.

When hydrocyanic acid and formaldehyde are reacted with dimethyliminodiacetic acid or its alkali metal salt, hydrocyanic acid is 1.0 to 2.0 times, preferably 1.
It is preferable to use 0 to 1.5 times mol. Formaldehyde is 1.0 to 2.0 times mol, preferably 1.0 to 1.5 times mol. When glycolonitrile is used instead of reacting hydrocyanic acid and formaldehyde, glycolonitrile is 1.0 to 2.0 times mol, preferably 1.0 to 2.0 times mol of dimethyliminodiacetic acid or its alkali metal salt.
It is better to use 1.5 times the molar amount. In the case of reacting a halogenocarboxylic acid, the amount of the halogenocarboxylic acid is from 1.0 to dimethyliminodiacetic acid or its alkali metal salt.
It is preferable to use 2.0 times mol, preferably 1.0 to 1.5 times mol.

The formaldehyde used for the reaction may be in any form such as a gaseous product, an aqueous solution product or a solid product such as paraformaldehyde. Industrially, 10 to 60% by weight, preferably 20 to 50% by weight, which are easily available
Aqueous solution products are used.

When these reactions are carried out in the presence of an alkali metal hydroxide, NaOH, KOH or the like is selected as the alkali metal hydroxide to be used, preferably NaOH.
Is used.

The amount of the alkali metal hydroxide is in the range of 1.0 to 2.5 times, preferably 1.0 to 1.5 times the mol of the compound having a nitrile group, the halogenocarboxylic acid or the unsaturated compound. A double molar range is preferred. Alkali metal hydroxide is a solid product with a purity of 80% or more or a concentration of 10
A 60% by weight aqueous solution is used.

When the product is acid-deposited after completion of the reaction, the acid used for the acid-deposition is a mineral acid such as sulfuric acid, hydrochloric acid or nitric acid, preferably sulfuric acid. The acid precipitation conditions are in the range of pH 0.5 to 2.5, preferably pH.
The range of 0.5 to 1.5 is preferable. The temperature during acid precipitation is 60 to
The temperature is in the range of 120 ° C, preferably 80 to 100 ° C. The time for acid precipitation is 1 to 20 hours, preferably 2 to 14
Time is good.

When the product is acid-hydrolyzed after the reaction, mineral acids such as sulfuric acid, hydrochloric acid and nitric acid are used as the acid used in the acid hydrolysis step, but sulfuric acid is preferably used. The pH in the acid hydrolysis step is p
H 0.5 to 2.5, preferably pH 0.5 to 1.
A range of 5 is good. The temperature during hydrolysis is 60 to 120 ° C.
Is preferably in the range of 80 to 100 ° C. The time of hydrolysis is 1 to 20 hours, preferably 2 to 14 hours.

When the product is alkali-hydrolyzed after completion of the reaction, the alkali metal hydroxide used in the alkali hydrolysis step is selected from NaOH, KOH and the like, like the alkali metal hydroxide used in the reaction, and is preferable. Is NaOH. The temperature in the alkali hydrolysis step is in the range of 40 to 120 ° C, preferably 60 to 1
A range of 00 ° C is preferable. The time of hydrolysis is 0.5 to 8.
5 hours, preferably 0.5 to 3.5 hours.

When comparing the performances of chelating agents, the chelate stability constant for the target metal is the index, but for builder applications, the Ca ²⁺ ion trapping ability is the index. When the dimethyliminodiacetic acid and the iminodiacetic acid, which are the raw materials in the present application, were compared in terms of Ca ²⁺ ion-capturing capacity per acid-equivalent weight, dimethyliminodiacetic acid showed a performance equivalent to 62% of that of iminodiacetic acid. Considering that the molecular weight of dimethyliminodiacetic acid is 121% of that of iminodiacetic acid, it can be said that the performance of dimethyliminodiacetic acid is retained even when two methyl groups are introduced.

Modified MIT for examining the biodegradability of dimethyliminodiacetic acid and iminodiacetic acid and the easy degradability of organic compounds.
As a result of comparison by Method I, it was found that both were completely decomposed within 7 days extremely quickly. Similarly, 2,2'-
When the biodegradability of dimethyl-β-alanine-N, N-diacetic acid was examined, it was found to show biodegradability comparable to β-alanine-N, N-diacetic acid.

[0027]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples.

Example 1 (Synthesis of 2,2'-dimethylnitrilotriacetic acid) Dimethyliminodiacetic acid (1.61) was added to a reactor equipped with a stirrer, an automatic temperature controller, a hydrogen cyanide introducing device and a distillation device.
2. kg (10.0 mol), 40 wt% NaOH aqueous solution 3.
Then, 00 kg (30.0 mol) was charged, and then 0.89 kg (11.0 mol) of 37 wt% aqueous formaldehyde solution was mixed. 0.29 kg (1
1.0 mol) under sealed conditions in the range of 50 to 90 ° C.,
The reaction temperature was gradually raised, and the mixture was added dropwise over 5 hours. During this time, 0.48 k of condensed water containing 25% by weight of ammonia
After distilling off g, the reaction mixture was aged for 5 hours, and 0.77 kg of condensed water containing 7.3% by weight of ammonia was distilled off. After confirming that the generation of ammonia was completed, 4.25 kg of water was added to the reaction solution to dilute it, and the mixture was allowed to cool to 50 ° C. To this reaction solution, 1.55 kg (15.5 mol) of 98% sulfuric acid was added dropwise over 1.5 hours, and the temperature was raised to 80 ° C. The reaction solution was allowed to cool to 33 ° C. again, the precipitated crystals of 2,2′-dimethylnitrilotriacetate were separated by a centrifuge, and further washed twice with water (10 kg). After blast drying, 2,2'-dimethylnitrilotriacetic acid 2.12k
g (purity 98%, yield 95%) was obtained as white crystals.

Example 2 (Synthesis of 2,2'-dimethylnitrilotriacetic acid-3Na salt) Dimethyliminodiacetic acid 1.61 was added to a reactor equipped with a stirrer, automatic temperature controller, hydrocyanic acid introduction device and distillation device.
kg (10.0 mol) and water 3.00 kg were charged, and then 37% by weight formaldehyde aqueous solution 0.89 kg
(11.0 mol) were mixed. 0.2% of hydrocyanic acid was added to this mixed solution.
9 kg (11.0 mol) under sealed conditions at 50 to 70 ° C
Within the range, the reaction temperature was gradually increased, and the mixture was added dropwise over 5 hours. After completion of dropping, the mixture was aged for 5 hours. During this period, condensed water containing ammonia was not distilled off. The reaction solution was diluted with 4.25 kg of water and allowed to cool to 20 ° C. After standing at 20 ° C. for 1 hour, precipitated N-
Wet crystals of cyanomethyl-dimethyliminodiacetic acid were isolated by suction filtration. The isolated N-cyanomethyl-dimethyliminodiacetic acid was added to a 40% by weight NaOH aqueous solution 3.00 kg.
Dissolve in (30.0 mol) and gradually increase the reaction temperature to 105 ° C.
The temperature was raised to. During this period, 1.25 kg of condensed water containing 15% by weight of ammonia was distilled off in 3 hours. After confirming that the generation of ammonia was completed, the slurry remaining in the reaction tank was dried and powdered at 120 ° C. by a spray drying method,
2,2'-Dimethylnitrilotriacetic acid-3Na salt 2.94
kg (purity 94% or more, yield 97% or more) was obtained as white crystals.

Example 3 (Synthesis of 2,2'-dimethylnitrilotriacetic acid) A reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a pH electrode was charged with 1.61 k of dimethyliminodiacetic acid.
g (10.0 mol), NaOH 0.8 kg (20.0 mol) and water 3.00 kg were charged, and the temperature was 50 while stirring.
Warmed to ° C. Monochloroacetic acid 0.945 was added to this solution.
A solution of 1 kg (10.0 mol) dissolved in 1 kg of water and a 40 wt% NaOH aqueous solution were simultaneously added dropwise while keeping the reaction solution at pH 9.5. The dropping time was 3 hours. After the dropping was completed, the reaction was continued at 50 ° C. for 3 hours. After cooling the reaction solution, 98% sulfuric acid was added to adjust the pH to 1.5. The precipitated crystals are separated using a centrifuge, washed twice with water (1.0 kg), dried, and then 2,
1.72 kg of 2'-dimethyl nitrilotriacetic acid (purity 98
%, Yield 77%). Table 1 shows the results.

Examples 4 to 6 (2,2 'using haloacetic acid)
-Dimethylnitrilotriacetic acid, 2,2'-dimethyl-β-
Synthesis of alanine-N, N-diacetic acid) Instead of monochloroacetic acid, monobromoacetic acid, 2-chloropropionic acid, and 2-bromopropionic acid were used to carry out the same reaction as in Example 3 to obtain 2,2′- Dimethylnitrilotriacetic acid and 2,2'-dimethyl-β-alanine-N, N-diacetic acid were obtained. Table 1 shows the results.

[0032]

[Table 1] DMNTA: 2,2'-dimethylnitrilotriacetate DNALDA: 2,2'-dimethyl-β-alanine-N, N-diacetic acid

Example 7 (Synthesis of 2,2'-dimethyl-β-alanine-N, N-diacetic acid) Dimethyliminodiacetic acid 1 was added to a reactor equipped with a stirrer, a thermometer, a dropping funnel and a distillation device. .61 kg (10.
0 mol), 3.00 kg of 40% by weight NaOH aqueous solution (3
0.0 mol), and under stirring at a temperature of 25 to 30 ° C.,
0.54 kg (10.0 mol) of acrylonitrile was added dropwise over 1 hour. After completion of dropping, the mixture was further stirred at 25 to 30 ° C. for 8 hours. To this reaction liquid, 0.5 kg of NaOH was added as a solid and dissolved. After thawing, the temperature of the reaction solution is adjusted to 10
When the temperature was raised to 5 ° C, vigorous foaming occurred, and stirring was continued while distilling 1.72 kg of ammonia water having a concentration of 10% by weight in 2.5 hours. After the generation of ammonia was completed, the reaction solution was cooled to 50 ° C. 9 in the cooled reaction mixture
1.55 kg of 8% sulfuric acid was added. This solution was cooled to 30 ° C. and precipitated 2,2′-dimethyl-β-alanine-
N, N-diacetic acid was collected by filtration and washed twice with water (1.0 kg). After drying, 2,2'-dimethyl-β-alanine-
1.97 kg of white crystals of N, N-diacetic acid (purity 98%,
The yield was 88%). Table 2 shows the results.

Examples 8 to 9 Acrylonitrile and acrylamide were used in place of acrylonitrile to carry out the same reaction as in Example 7,
2'-Dimethyl-β-alanine-N, N-diacetic acid was obtained. Table 2 shows the results.

[0035]

[Table 2] DMALDA: 2,2′-dimethyl-β-alanine-N, N-diacetic acid

Test Examples 1 to 3 (Biodegradability Test) The dimethyliminodiacetic acid derivatives synthesized in Examples 1 to 9 were biodegraded by the method according to the modified MITI test (II) described in OECD test guideline 302C for chemicals. Tested for sex. Table 3 shows the results. (Test conditions) Test sample concentration: 30 mg / l Activated sludge: Nitto Kagaku Yokohama site activated sludge Activated sludge concentration: 100 mg / l Test temperature: 25 ± 1 ° C Test period: 28 days

Comparative Examples 1 to 3 (Biodegradability Test) As test compounds, iminodiacetic acid, nitrilotriacetic acid, β
-Alanine-N, N-diacetic acid was used to test the biodegradability in the same manner as in Test Example 1. Table 3 shows the results.

[0038]

[Table 3] DMIDA: dimethyliminodiacetic acid DMNTA: 2,2'-dimethylnitrilotriacetic acid DMALDA: 2,2'-dimethyl-β-alanine-N, N-diacetic acid IDA: iminodiacetic acid NTA: nitrilotriacetic acid ALDA: β- Alanine-N, N-diacetic acid

[0039] The Ca ²⁺ trapping ability of the test examples 4 to 6 (Ca ²⁺ trapping ability test) compound synthesized in Example 1~9, J. Am.
It was measured at pH 12 according to the method described in Oil. Chem. Soc., 1970, 48, 682 page. Table 4 shows the results.

Comparative Examples 4 to 6 (Ca ²⁺ capture ability test) As test compounds, iminodiacetic acid, nitrilotriacetic acid, β
-Alanine-N, N-diacetic acid was used to test the Ca ²⁺ capturing ability in the same manner as in Test Example 4. Table 4 shows the results.

[0041]

[Table 4] DMIDA: dimethyliminodiacetic acid DMNTA: 2,2'-dimethylnitrilotriacetic acid DMALDA: 2,2'-dimethyl-β-alanine-N, N-diacetic acid IDA: iminodiacetic acid NTA: nitrilotriacetic acid ALDA: β- Alanine-N, N-diacetic acid

[0042]

According to the method of the present invention, dimethyliminodiacetic acid is a biodegradable chelating agent, or 2,2'-dimethylnitrilotriacetic acid or 2,2'-dimethyl-β-alanine-N, N. It can be used as a raw material for synthesizing a biodegradable chelating agent such as diacetic acid. The present invention also has the following advantages. (1) Dimethyliminodiacetic acid, 2,2'-dimethylnitrilotriacetic acid, 2,2'-dimethyl-β-alanine-N,
The biodegradability of N-diacetic acid is equal to that of iminodiacetic acid, nitrilotriacetic acid, or β-alanine-N, N-diacetic acid,
More than that. (2) Dimethyliminodiacetic acid, 2,2'-dimethylnitrilotriacetic acid, 2,2'-dimethyl-β-alanine-N,
N-diacetic acid can be used as a biodegradable chelating agent because it has an excellent Ca ²⁺ capture ability. (3) According to the method of the present invention for synthesizing 2,2′-dimethylnitrilotriacetic acid and 2,2′-dimethyl-β-alanine-N, N-diacetic acid from dimethyliminodiacetic acid, the process is easy and The target product can be obtained with high recovery and high purity.

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Claims (4)

[Claims] 1. A 2,2′-represented by the following general formula [1]:
A biodegradable chelating agent comprising at least one dimethyliminodiacetic acid derivative as an active ingredient. General formula [1] [In the formula, R is a hydrogen atom, -CH ₂ COOX ₃ or -C
H ₂ CH ₂ COOX ₃ is represented, and X ₁ , X ₂ and X ₃ represent a hydrogen atom, Na or K. ] 2. A 2,2′-represented by the following general formula [2]:
A 2,2′-dimethyliminodiacetic acid derivative represented by the following general formula [3] and an alkali metal salt thereof, characterized by reacting dimethyliminodiacetic acid or an alkali metal salt thereof with a compound having a nitrile group. Manufacturing method. General formula [2] [In the formula, X ₁ and X ₂ represent a hydrogen atom, Na or K. ] General formula [3] [Wherein, R -CH ₂ COOX ₃ or -CH ₂ CH ₂
COOX ₃ , wherein X ₁ , X ₂ and X ₃ are hydrogen atoms, Na
Or K is indicated. ] 3. A method for producing a compound of the above general formula [3], which comprises reacting the compound of the above general formula [2] with a halogenocarboxylic acid. 4. The compound of the general formula [3], wherein the compound of the general formula [2] is reacted with an unsaturated compound.
A method for producing the compound of