JP2000219662A - Amino ether carboxylic acid or its salt and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound useful as a chelating agent having high water solubility, chelating performances and biodegradability by making the compound include an amino ether carboxylic acid. SOLUTION: This compound is shown by formula I [X1 and X2 are each an alkali metal or the like; R1 and R2 are each H or a group of the formula CH(COOX3)CH2(COOX4) (X3 and X4 are each an alkali metal or the like)] such as tetrasodium salt (II) of amino ether carboxylate. The compound of formula I is obtained by reacting 1 mol of an aminoalcohol of formula III with preferably 1.5-3 mols of maleic acid and/or its salt (e.g. maleic acid or maleic anhydride) in the presence of a rare earth metal salt (e.g. lanthanum) in an aqueous medium preferably at 80-120 deg.C for 2-5 hours. The amount of the rare earth metal salt is preferably 0.02-1.2 mol equivalent based on maleic acid and/or its salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel aminoether carboxylic acid or a salt thereof, and a method for producing the same. More specifically, the present invention relates to an aminoethercarboxylic acid or a salt thereof which has high water solubility and chelating performance and is useful as a chelating agent having excellent biodegradability, and a method for producing the same.

[0002]

2. Description of the Related Art Chelating agents are used in various fields such as fibers, paper pulp, detergents, metal surface treatments and photographs for the purpose of sequestering metal ions, and are indispensable for removing the adverse effects of metal ions. Not something. Among them, the removal of calcium and magnesium in hard water is a process that is required in many fields including detergents, and in the bleaching process of the textile and pulp and paper industries, hydrogen peroxide such as bleaching agent is used. A chelating agent is used to suppress the decomposition of the metal by a metal. As a chelating agent widely used conventionally, there is ethylenediaminetetraacetic acid. However, it has been pointed out that this compound has poor microbial degradability and is not easily biodegradable, so that industrial wastewater containing ethylenediaminetetraacetic acid is not decomposed by ordinary activated sludge treatment, and its use is considered from the viewpoint of environmental protection. Is concerned.

[0003] Therefore, there is a demand for the development of a compound having excellent chelating ability, microbial degradability and water solubility.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and is useful as a chelating agent having high water solubility and chelating performance and excellent in biodegradability. An object of the present invention is to provide a compound and a method for producing the compound.

[0005]

Means for Solving the Problems The present inventors have made intensive studies in view of the above circumstances, and as a result, have found that the amino ether carboxylic acid represented by the following formula (1) or a salt thereof has high water solubility and chelating ability. Because of its excellent biodegradability and high biodegradability, the present inventors have found a compound useful as an environmentally friendly water-soluble chelating agent without polluting the environment while exhibiting high chelating performance. Based on the above findings, the present invention has been completed.

[0006] That is, the above objects are as follows:
(D) is achieved. (A) The following equation (1):

[0007]

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Wherein X ¹ and X ² each independently represent an alkali metal, an alkaline earth metal or an ammoniacal base; and R ¹ and R ² each independently represent hydrogen or a formula: —CH (COOX ³ ) CH ₂ (COO ³
X ⁴ ) and R ¹ and R ² do not simultaneously represent hydrogen, wherein X ³ and X ⁴ are each independently an alkali metal, alkaline earth metal or ammoniacal An amino ether carboxylic acid or a salt thereof represented by the formula: (B) The following equation (2):

[0009]

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However, X ¹ and X ² each independently represent an alkali metal, an alkaline earth metal or an ammoniacal base, which is obtained by reacting an amino alcohol represented by the formula with maleic acid and / or a salt thereof. The method for producing an aminoether carboxylic acid or a salt thereof according to the above (A). (C) The method according to (a), wherein the reaction between the amino alcohol and maleic acid and / or a salt thereof is performed in the presence of a rare earth metal salt or an alkaline earth metal salt. (D) The method according to (A) or (C) above, wherein the reaction between the amino alcohol and maleic acid and / or a salt thereof is carried out in an aqueous medium.

[0011]

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

According to a first concept of the present invention, the following equation (1):

[0013]

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An amino ether carboxylic acid represented by the formula or a salt thereof is provided.

In the above formula (1), R ¹ and R ² are each independently hydrogen or a formula: —CH (COOX ³ )
Represents a group represented by CH ₂ (COOX ⁴ ) (hereinafter, simply referred to as “formula (3)”), wherein R ¹ and R ² are
^They do not represent hydrogen at the same time [in other words, R ¹ and R ²
At least one represents a group represented by the formula (3)].
In the above formula (3), X ³ and X ⁴ are each independently an alkali metal such as sodium, potassium, lithium; an alkaline earth metal such as calcium or magnesium; or a monoethylamine, diethylamine, triethylamine or the like. Alkanolamine bases such as alkylamine bases, monoethanolamine, diethanolamine, and triethanolamine; polyamine bases such as ethylenediamine and triethylenediamine; and ammoniacal bases such as ammonia base. Of these examples, X ³
And X ⁴ preferably each independently represents sodium.

In the above formula (1), X ¹ and X ²
Are each independently an alkali metal such as sodium, potassium and lithium; an alkaline earth metal such as calcium and magnesium; or an alkylamine base such as monoethylamine, diethylamine and triethylamine, monoethanolamine, diethanolamine, triethanolamine and the like. Alkanolamine bases, polyamine bases such as ethylenediamine and triethylenediamine, and ammoniacal bases such as ammonia base. Of these examples, X ¹ and X ² preferably each independently represent sodium. In the present invention, X ^{1 to} X ⁴ in the above formulas (1) and (3) may be the same or different.

Preferred specific examples of the amino ether carboxylic acid represented by the above formula (1) or a salt thereof include the following. R ¹ represents hydrogen; R ² has the formula: —CH (COONa) C
An aminoether carboxylate salt wherein H ¹ represents H ₂ (COONa); and X ¹ and X ² represent sodium; and R ¹ has the formula: —CH (COONa) CH ₂ (COONa)
R ² represents hydrogen; and X ¹ and X ² represent sodium; an aminoether carboxylate salt; and R ¹ and R ² have the formula: —CH (COONa) CH ₂ (CO
ONa); and X ¹ and X ² represent sodium.

Of these, considering the desired properties, the following formula [that is, in formula (1), R ¹ represents hydrogen;
Wherein R ² represents the formula: —CH (COONa) CH ₂ (COONa); and X ¹ and X ² represent sodium] are particularly preferably used in the present invention.

[0019]

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The amino ether carboxylic acid or its salt of the present invention represented by the above formula (1) is a compound which has excellent water solubility and chelate performance and is easily decomposed by biodegradation means such as activated sludge.

The amino ether carboxylic acid represented by the above formula (1) or a salt thereof may have optical isomers. In the present invention, a racemic form may be used, or individual optical isomers may be used. The isomers may be used alone as individual optical isomers by synthesizing or resolving the racemate.

According to a second concept of the present invention, the following equation (2):

[0023]

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Wherein X ¹ and X ² each independently represent an alkali metal, an alkaline earth metal or an ammoniacal base (hereinafter sometimes simply referred to as “aminoalcohol”). And maleic acid and / or a salt thereof. The method for producing an aminoethercarboxylic acid or a salt thereof according to the present invention is provided.

X ¹ and X ² in the above formula (2) are the same as the definitions of X ¹ and X ² in the above formula (1), respectively.

In the present invention, the amino alcohol can be produced by a method known in the art, and the production method thereof is not particularly limited. For example, by reacting epoxysuccinic acid with ethanolamine,
Obtained easily.

As used herein, the term "maleic acid salt" means that at least one of the hydrogen atoms in the carboxyl group of maleic acid is an alkali metal such as sodium, potassium or lithium; Alkaline earth metals; and alkylamine bases such as monoethylamine, diethylamine and triethylamine; alkanolamine bases such as monoethanolamine, diethanolamine and triethanolamine; polyamine bases such as ethylenediamine and triethylenediamine; and ammoniacal bases such as ammonia base. And maleic anhydride. When both hydrogen atoms in the carboxyl group of maleic acid are substituted with the above-mentioned substituents, the substituents may be the same or different.

Among these, examples of maleic acid and / or a salt thereof preferably used as a raw material of the method of the present invention include maleic acid, maleic anhydride, sodium maleate, potassium maleate and ammonium maleate. And especially maleic anhydride.

In the present invention, the use amount of maleic acid and / or a salt thereof is preferably in excess with respect to the use amount of amino alcohol. ４4 mol, preferably 1.2-3.5 mol, more preferably 1.5-3 mol.

In the method of the present invention, the reaction between the amino alcohol and maleic acid and / or a salt thereof is preferably carried out in the presence of a rare earth metal salt or an alkaline earth metal salt.

The rare earth metal salt used as a catalyst in the above embodiment includes lanthanoid metals such as lanthanum, cerium, praseodymium and neodymium; chlorides such as scandium and yttrium, nitrates and sulfates. Of these, lanthanum chlorides, nitrates and sulfates, particularly lanthanum chloride, are preferably used from the viewpoint of relatively low cost and availability. On the other hand, examples of the alkaline earth metal salt used as a catalyst in the above embodiment include hydroxides, such as calcium, magnesium, beryllium, strontium, barium, and radium, chlorides, nitrates, and sulfates. Of these, calcium hydroxide, chloride, nitrate and sulfate, particularly calcium hydroxide, are preferably used. When a rare earth metal salt or an alkaline earth salt is used as a catalyst in the method of the present invention,
The amount used is usually maleic acid and / or
0.01 mol equivalent or more, preferably 0.015 to 2 mol equivalent, more preferably 0.02 to 2
1.2 molar equivalents.

In the method of the present invention, the reaction between the amino alcohol and maleic acid and / or a salt thereof is as follows:
It is preferably carried out in an aqueous medium.

The aqueous medium used in the above embodiment includes water and dioxane. Of these, water is preferably used in consideration of toxicity, cost, availability, and the like.

Further, the conditions for the reaction between the amino alcohol and maleic acid and / or its salt are not particularly limited as long as these raw materials react efficiently.
It depends on whether or not a catalyst or an aqueous medium is used and the type of raw material used. For example, when the reaction between the amino alcohol and maleic acid and / or a salt thereof is performed in the presence of a rare earth metal salt or an alkaline earth metal salt, the reaction temperature is usually 50 to 150 ° C, preferably 80 to 120 ° C. The reaction is carried out by stirring the raw materials at this reaction temperature, usually for several hours (usually 2 to 5 hours). The reaction pressure is not particularly limited as long as the raw materials react efficiently, and may be normal pressure, pressurized or reduced pressure, but is preferably normal pressure in consideration of easiness of operation. .

Having described the second concept of the present invention above, one embodiment of the second concept of the present invention is described below. Reacting the amino alcohol and maleic acid and / or a salt thereof in the presence of a rare earth metal salt or an alkaline earth metal salt at a reaction temperature of 50 to 150 ° C. for 1 to 20 hours,
The reaction is carried out by heating and stirring to obtain the rare earth metal salt or the alkaline earth metal salt of the aminoethercarboxylic acid of the present invention.

In order to obtain the amino ether carboxylic acid salt of the present invention as an alkali metal salt, for example, when the amino ether carboxylic acid of the present invention is obtained as an alkaline earth metal salt, an alkali metal salt of the amino ether carboxylic acid is used. Salt exchange is performed by adding an alkali metal carbonate and / or bicarbonate to the earth metal salt to precipitate a rare earth carbonate or an alkaline earth carbonate contained in the system and to filter the system from the system. By this means, the alkali metal salt of amino ether carboxylic acid of the present invention is obtained as an aqueous solution. Examples of the alkali metal carbonate and / or bicarbonate added in the above embodiment include sodium carbonate, potassium carbonate and lithium carbonate, sodium bicarbonate, potassium bicarbonate and lithium bicarbonate. Sodium is preferred.

In order to obtain the aminoether carboxylate of the present invention as an ammonium salt, salt exchange is performed by adding ammonium carbonate and / or ammonium bicarbonate to the alkaline earth metal salt of aminoether carboxylic acid. Is carried out to precipitate the rare earth carbonate or alkaline earth carbonate contained in the system and remove it from the system by means of filtration or the like, whereby the ammonium salt of the amino ether carboxylic acid of the present invention is obtained as an aqueous solution.

Alternatively, in the above embodiment, after salt exchange,
For example, the amino ether carboxylic acid of the present invention may be liberated as an acid by a usual acid precipitation method such as adding a mineral acid such as hydrochloric acid or sulfuric acid.

[0039]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Example 1: Synthesis of N-hydroxyethyl-hydroxyaspartic acid (I) 26.4 g of cis-epoxysuccinic acid, 30 g of water and 4
After charging 33.4 g of an 8% by weight aqueous sodium hydroxide solution into a four-necked flask, 12.2 g of ethanolamine was added thereto, and the mixture was stirred at 90 ° C. for 8 hours to give N-hydroxyethyl-hydroxy having the following structural formula. Aspartic acid (I) was obtained as the target compound (I) in a yield of 97.0%.

[0040]

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With respect to the obtained compound (I), ¹ H—N
When confirmed by MR, the following results were obtained.

¹ H-NMR (D ₂ O) 4.18 ppm (1H) 3.52 ppm (2H) 3.35 ppm (1H) 2.69-2.43 ppm (2H) Example 2: amino ether carboxyl of the present invention Synthesis of acid salt To 58.0 g of the aqueous solution containing 0.1 mol of the compound (I) obtained in Example 1, 9.8 g of maleic anhydride and 37.1 g of lanthanum chloride heptahydrate were added, and sodium hydroxide was added. And p
After adjusting H to 8.5, stirring was performed at 90 ° C. 8
After an hour, the reaction solution was cooled to 60 ° C., 17.5 g of sodium carbonate was added, and the mixture was stirred at 60 ° C. for 1 hour, and lanthanum carbonate precipitated was separated by filtration. The reaction product (A) obtained after distilling off water is a colorless solid, and when this reaction product is analyzed, the main product is the desired amino ether carboxylic acid 4 having the following structural formula. Sodium salt (I
I) (yield: 65%).

[0043]

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The main product was confirmed by ¹ H-NM
When performed with R, the following results were obtained.

¹ H-NMR (D ₂ O) 4.48-4.39 ppm (1H) 4.16 ppm (1H) 3.55-3.47 ppm (2H) 3.40 ppm (1H) 2.78-2. 20 ppm (4H) Example 3: Measurement of chelate stability constant The calcium stability constant (pKCa) of the tetrasodium salt (II) of the aminoethercarboxylic acid obtained in Example 2 was determined.
²⁺ ) was measured as follows, and the results are shown in Table 1 below. In addition, citric acid and zeolite were used as comparative controls. <Calculation method of calcium stability constant (pKCa 2 ⁺ )>
First, a standard calcium ion solution is prepared, and a calibration curve showing the relationship between the logarithm of the calcium ion concentration and the potential as shown in FIG. 1 is prepared.

Next, 0.1 g was placed in a 100 ml volumetric flask.
Was weighed, and a buffer solution (composition: 0.1 M NH ₄
Cl-NH ₄ OH buffer, filled up with pH 10). To this, a CaCl ₂ solution (pH 10) equivalent to 20,000 ppm (CaCO ₃ equivalent) is dropped from a burette (blanks are also measured). Dropping is performed by adding 0.1 to 0.2 ml of a CaCl ₂ solution, the potential at that time is read, and the calcium ion concentration is determined from the calibration curve of FIG. The calcium ion concentration at the dropping amount A of the CaCl ₂ solution in FIG. 2 becomes the calcium ion trapping ability of the sample.

Further, as the calcium ion chelate stability constant (pKCa ²⁺ ), the result at the time of measuring the Ca ²⁺ capturing ability is used. Calculate as forming a one-to-one complex when equimolar calcium is added to the sample. The stability constant of the complex is determined according to the following equation.

[0048]

(Equation 1)

[0049]

[Table 1]

As shown in Table 1, the aminoethercarboxylic acid tetrasodium salt (II) of the present invention exhibits a higher calcium stability constant than citric acid or zeolite. .

[0051]

As described above, the aminoethercarboxylic acid of the present invention represented by the formula (1) or a salt thereof has high water solubility and chelating performance and is excellent in biodegradability. The contained chelating agent becomes an environmentally friendly water-soluble chelating agent without polluting the environment while exhibiting high chelating performance.

Further, according to the production method of the present invention, the amino ether carboxylic acid of the present invention or a salt thereof can be produced efficiently with a high yield.

[Brief description of the drawings]

FIG. 1 is a calibration curve showing the relationship between the logarithm of calcium ion concentration and potential.

FIG. 2 is a graph showing the relationship between the amount of CaCl ₂ solution dropped and the calcium ion concentration when measuring the calcium ion capturing ability.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomomi Ina 5-8 Nishiburi-cho, Suita-shi, Osaka Nippon Shokubai Co., Ltd. F-term (reference) 4H006 AA01 AA02 AB82 AC43 BA06 BA08 BA37 BB31 BN10 BP10 BS10 BS70 BU32

Claims (4)

[Claims] 1. The following formula (1): Wherein X ¹ and X ² each independently represent an alkali metal, an alkaline earth metal or an ammoniacal base;
And R ¹ and R ² each independently represent hydrogen or a group represented by the formula: —CH (COOX ³ ) CH ₂ (COOX ⁴ ), and R ¹ and R ² do not simultaneously represent hydrogen. Wherein X ³ and X ⁴ each independently represent an alkali metal, an alkaline earth metal or an ammoniacal base, or an aminoethercarboxylic acid or a salt thereof. 2. The following formula (2): Wherein X ¹ and X ² each independently represent an alkali metal, an alkaline earth metal or an ammoniacal base;
The method for producing an aminoether carboxylic acid or a salt thereof according to claim 1, comprising reacting the amino alcohol represented by the formula with maleic acid and / or a salt thereof. 3. The method according to claim 2, wherein the reaction between the amino alcohol and maleic acid and / or a salt thereof is carried out in the presence of a rare earth metal salt or an alkaline earth metal salt. 4. The method according to claim 2, wherein the reaction of the amino alcohol with maleic acid and / or a salt thereof is carried out in an aqueous medium.