JPH10120619A - Production of alkali metal salt of ether carboxylic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for economically and advantageously producing an alkali metal salt of an ether carboxylic acid by reacting an organic compound containing OH with an epoxy compound, etc., by using a rare earth element ion as a catalyst and separating and recovering the catalyst by adding an alkali metal hydroxide after the reaction. SOLUTION: This method for producing an alkali metal salt of an ether carboxylic acid comprises a step for reacting (C) an organic compound containing OH (e.g. a hydroxy carboxylic acid compound, a polyvalent alcoholic compound, a 6-22C alcoholic compound and saccharides) with (D) an unsaturated carboxylic acid compound (e.g. an unsaturated monocatboxylic acid and an unsaturated dicarboxylic acid) or an epoxy compound (e.g. an epoxy compound containing a carboxyl) in an aqueous medium in the presence of (A) an alkali metal ion and (B) a rare earth element ion as a catalyst, and a step for adding (E) an alkali metal hydroxide thereto after the reaction to separate and recover the component B from the reaction mixture as a hydroxide.

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 an alkali metal ether carboxylate, and more particularly, to an organic compound having a hydroxyl group and an unsaturated carboxylic acid in an aqueous medium in the presence of an alkali metal ion and a rare earth ion as a catalyst. When reacting with an acid compound or an epoxy compound to produce a corresponding alkali metal salt of ether carboxylic acid, after the reaction is completed, the rare earth element ions in the reaction solution are separated,
The present invention relates to a method for recovering and further reusing as a catalyst.

[0002]

BACKGROUND OF THE INVENTION Sodium carboxymethoxysuccinate, one of the alkali metal salts of ether carboxylic acids, is useful as a phosphorus-free detergent builder. This compound is prepared by dissolving maleic anhydride and glycolic acid in an aqueous medium. It is also known to be obtained by reacting in the presence of neutral calcium hydroxide (Chemical Abstract, 7).
5 , 89458 (1971)). In the case of this method, since the reaction is a homogeneous reaction using water-soluble calcium hydroxide as a catalyst, in order to obtain sodium carboxymethoxysuccinate useful as a detergent builder, sodium carbonate is added to convert calcium ions into carbonate. It must be precipitated as calcium and separated.

In the same homogeneous reaction as described above, lanthanum (II) is used as a catalyst instead of calcium ion.
It has been reported that the ions of I) can also be used (J.
Chem. Soc. Dalton Trans. , 27
23-2728 (1988)). That is, when sodium glycolate and sodium maleate are reacted in water in the presence of lanthanum trichloride, a salt of carboxymethoxysuccinic acid (a salt of sodium and lanthanum) is obtained. Therefore, in order to obtain a sodium salt of carboxymethoxysuccinic acid useful as a detergent builder, it is necessary to separate lanthanum ions from the reaction solution using an ion exchange resin or the like.

[0004]

In order to reduce the production cost, it is common practice to recover and reuse the catalyst used in the reaction.

However, the corresponding alkali metal carboxymethoxysuccinate is produced by a homogeneous reaction between glycolic acid (alkali metal salt) and maleic acid (alkali metal salt) in an aqueous medium using lanthanum ion as a catalyst. In this case, an effective method of collecting and reusing the used lanthanum ions has not been reported yet.

[0006] The method of separating lanthanum ions using the ion exchange resin as described above requires a separation step using the ion exchange resin, and a reduction in production cost can hardly be expected.

Further, it is conceivable to add sodium carbonate to separate lanthanum ions as lanthanum carbonate using a known method of adding and separating calcium carbonate as calcium carbonate by adding the above-mentioned sodium carbonate. However, in this case, even if lanthanum ions can be separated and recovered as lanthanum carbonate, this lanthanum carbonate cannot be used as it is as a supply source of lanthanum ions because it does not dissolve in the aqueous solution containing the starting material. Therefore, in order to reuse lanthanum carbonate, a water-soluble lanthanum compound such as lanthanum trichloride,
Alternatively, it is necessary to convert the lanthanum compound into a lanthanum compound which is dissolved in the aqueous solution of the starting material. Providing such a conversion step rather increases the production cost.

Thus, an object of the present invention is to react an organic compound having a hydroxyl group with an unsaturated carboxylic acid compound or an epoxy compound in an aqueous medium in the presence of an alkali metal ion and a rare earth element ion as a catalyst to form an ether carboxylic acid. In the method for producing an acid alkali metal salt,
After the completion of the reaction, the rare earth element ions in the reaction solution are separated and recovered by a simple method, and further reused as a catalyst.
An object of the present invention is to provide a method for producing an alkali metal salt of ether carboxylic acid.

[0009]

Means for Solving the Problems The present inventors reacted glycolic acid (sodium salt) and maleic acid (sodium salt) in water in the presence of lanthanum ion to form the corresponding sodium salt of carboxymethoxysuccinic acid. As a result of diligent research on the method of producing, the following findings were obtained.

(1) After the reaction is completed, sodium hydroxide is added to the reaction solution to convert the lanthanum ion to lanthanum hydroxide. This lanthanum hydroxide is hardly soluble in a neutral or alkaline aqueous solution. Can be easily separated.

(2) Lanthanum hydroxide is readily soluble in acidic aqueous solutions and is soluble in aqueous solutions containing glycolic acid and maleic acid.

Thus, the present inventors have found that when glycolic acid and maleic acid are reacted in an aqueous medium in the presence of sodium ion and lanthanum ion as a catalyst to produce the corresponding sodium salt of carboxymethoxysuccinic acid. After the completion of the reaction, sodium hydroxide is added, and lanthanum ions in the reaction solution are separated and recovered as lanthanum hydroxide. In reusing the lanthanum hydroxide as a catalyst, the lanthanum hydroxide is converted into an acidic aqueous solution. It was found that by dissolving in it, it could be reused as a lanthanum ion source, and based on this finding, the present invention was completed.

That is, the present invention provides an ether carboxylic acid by reacting an organic compound having a hydroxyl group with an unsaturated carboxylic acid compound or an epoxy compound in an aqueous medium in the presence of an alkali metal ion and a rare earth element ion as a catalyst. In the method for producing an alkali metal salt, an ether carboxylic acid compound characterized by adding an alkali metal hydroxide after completion of the reaction, separating and recovering a rare earth element ion in the reaction solution as a rare earth element hydroxide. It is a manufacturing method of.

The present invention is also a method for producing an ether carboxylic acid compound, wherein the recovered rare earth element hydroxide is reused as a catalyst.

The feature of the present invention resides in the fact that the above-mentioned properties of the rare earth element hydroxide are used in a homogeneous reaction using a rare earth element ion as a catalyst.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The rare earth element used in the present invention means a lanthanoid element, scandium and yttrium. Representative examples of the lanthanoid elements include lanthanum, cerium, praseodymium, neodymium and the like. Among these lanthanoid elements, scandium and yttrium, lanthanum is particularly preferably used. The organic compound having a hydroxyl group of the present invention is a hydroxycarboxylic acid compound, a polyhydric alcohol compound, a higher alcohol compound having 6 to 22 carbon atoms, and a saccharide. These organic compounds are described more specifically as follows. .

(1) Hydroxycarboxylic acid compound (a) A compound represented by the following general formula (1).

[0018]

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In the formula, R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom, an ammonium group, Represents an alkyl ammonium group or an alkanol ammonium group, and m represents an integer of 1 to 10. Representative examples include glycolic acid, β-hydroxypropionic acid, lactic acid and the like.

(B) A compound represented by the following general formula (2).

[0021]

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In the formula, R ³ is a hydrogen atom or a group having 1 to 3 carbon atoms.
Wherein n represents an integer of 1 to 10, and X has the same meaning as in formula (1). Representative examples include glyceric acid and gluconic acid.

(C) A compound represented by the following general formula (3).

OH—CH ₂ — (CH ₂ —O—CH ₂ ) p-COOX (3) wherein p represents an integer of 1 to 10, and X has the same meaning as in general formula (1). It is. A typical example is diethylene glycol monocarboxylic acid.

(D) A compound represented by the following general formula (4).

[0026]

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In the formula, R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ⁶ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a hydroxyl group. And X is as defined in general formula (1). Representative examples include malic acid and tartaric acid.

(E) A compound represented by the following general formula (5).

[0029]

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In the formula, R ⁷ is a hydrogen atom or a group having 1 to 3 carbon atoms.
Wherein X is as defined in general formula (1). Representative examples include tartronic acid.

(F) A compound represented by the following general formula (6).

[0032]

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In the formula, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X has the same meaning as in the general formula (1). is there. A typical example is citric acid.

(2) Polyhydric alcohol compound (a) A compound represented by the following general formula (7).

[0035]

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In the formula, R ^{12 to} R ¹⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Representative examples include ethylene glycol and isopropylene glycol.

(B) 2-1 of the compound of the above general formula (7)
Condensate of 0.

Representative examples include diethylene glycol.

(C) Glycerin and its derivatives.

Typical examples include glycerin, diglycerin, polyglycerin and the like.

(D) sorbitol, 1,4-sorbitan, pentaerythritol, dipentaerythritol and the like.

(3) A higher alcohol compound having 6 to 22 carbon atoms (R-OH).

As typical examples, R is hexyl, heptyl, octyl, nonyl, decyl, undecyl, lauryl, myristyl, palmityl, stearyl, arachidyl, behenyl, oleyl, linole, linolenyl, 2-
Alcohols such as ethylhexyl can be mentioned.

(4) Sugars.

Representative examples include glucose, mannose, galactose, fructose, lactose, sucrose and the like.

The unsaturated carboxylic acid compound of the present invention is an unsaturated monocarboxylic acid and an unsaturated dicarboxylic acid. These carboxylic acids will be described more specifically as follows.

(1) Unsaturated monocarboxylic acid compound (a) A compound represented by the following general formula (8).

[0048]

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In the formula, R ^{16 to} R ¹⁸ each independently represent
X represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms;
Has the same meaning as in formula (1). Representative examples include acrylic acid and methacrylic acid.

(2) Unsaturated dicarboxylic acid compound (a) A compound represented by the following general formula (9).

[0051]

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In the formula, R ¹⁹ and R ²⁰ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and X has the same meaning as in formula (1). A typical example is maleic acid. The unsaturated dicarboxylic acid may be an anhydride.

The epoxy compound of the present invention is an epoxy compound having the following carboxyl group.

(1) A compound represented by the following general formula (10).

[0055]

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In the formula, R ^{21 to} R ²⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or — (C
H ₂ ) n-COOX (where n is an integer of 0 to 10 and X is the same as in general formula (1)), at least one of which is-(CH ₂ ) n-COOX It is. Representative examples include glycidic acid, epoxysuccinic acid, and the like.

Therefore, in a preferred embodiment of the present invention, (A) glycolic acid, β-hydroxypropionic acid, lactic acid, glyceric acid, gluconic acid, diethylene glycol monocarboxylic acid, malic acid, tartaric acid, tartronic acid, citric acid, etc. Hydroxycarboxylic acids of ethylene glycol, isopropylene glycol, diethylene glycol, glycerin, diglycerin, polyglycerin,
Polyhydric alcohols such as sorbitol, 1,4-sorbitan, pentaerythritol, dipentaerythritol;
A higher alcohol having 6 to 22 carbon atoms; and glucose;
At least one compound selected from saccharides such as mannose, galactose, fructose, lactose and sucrose, and (B) an unsaturated monocarboxylic acid such as acrylic acid and methacrylic acid; and an unsaturated dicarboxylic acid such as maleic anhydride The corresponding epoxy compound is produced by reacting at least one compound selected from acids or reacting the compound (A) with an epoxy compound (C) such as glycidic acid or epoxy succinic acid.

In a particularly preferred embodiment, glycolic acid, malic acid, tartaric acid or tartronic acid of the compound (A) and (anhydrous) of the compound (B) are preferred.
The corresponding ether carboxylic acid compound is produced by reacting maleic acid or the epoxy succinic acid of the compound (C).

In the present invention, the reaction formula between (A) an organic compound having a hydroxyl group and (B) an unsaturated carboxylic acid or (C) an epoxy compound is represented by (A) glycolic acid,
The case where maleic acid is used as (B) and epoxysuccinic acid is used as (C) is as follows. The alkali metal atom as a counter ion is omitted.

Reaction of glycolic acid with maleic acid

[0061]

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Reaction of glycolic acid with epoxysuccinic acid

[0063]

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The alkali metal ether carboxylate obtained by the method of the present invention can be obtained by specifying the starting materials.
It can be easily specified according to the above equation. The alkali metal ether carboxylate obtained by the method of the present invention is generally one in which all carboxyl groups have been substituted with alkali metal atoms.

Next, the method for producing the alkali metal ether carboxylate of the present invention will be described in detail below.

An organic compound having a hydroxyl group as a starting material, an unsaturated carboxylic acid compound or an epoxy compound, and a rare earth element compound as a catalyst are dissolved in an aqueous medium, usually water.

Usually, in the first reaction, a water-soluble compound such as lanthanum trichloride, lanthanum nitrate, lanthanum sulfate or the like is used as the rare earth element compound in the case of lanthanum. In the second and subsequent reactions, the recovered rare earth element hydroxide, for example, lanthanum hydroxide is used. Of course, in the first reaction, a rare earth element hydroxide may be used.

When water-soluble lanthanum trichloride is used as the rare earth element compound in the first reaction, for example, sodium hydroxide is added to increase the solubility of lanthanum trichloride. The pH of the reaction solution is preferably adjusted to neutral or alkaline. Specifically, after adding an organic compound having a hydroxyl group and an unsaturated carboxylic acid compound or an epoxy compound in an aqueous medium, the pH is adjusted by adding sodium hydroxide, and then lanthanum trichloride is added. It may be dissolved, or after adding an organic compound having a hydroxyl group, an unsaturated carboxylic acid compound or an epoxy compound and lanthanum trichloride, adjusting the pH by adding sodium hydroxide, and then dissolving.

Next, the pH of the resulting aqueous solution is adjusted to the range of 6 to 9, preferably 7 to 8. If the pH is less than 6,
The reaction rate of the subsequent etherification reaction is remarkably reduced. On the other hand, when the pH exceeds 9, a rare earth element hydroxide is formed and precipitated, so that the reaction rate is reduced. To adjust this pH,
Usually, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are used, but sodium hydroxide is particularly preferably used.

After the above pH adjustment, an etherification reaction is carried out at a pH in this range.
Heating at a temperature in the range of 0 ° C, preferably 70-120 ° C, facilitates the process. The reaction is preferably performed with sufficient stirring.

The reaction pressure may be normal pressure or pressurization, but the reaction is usually performed under normal pressure. The ratio of (A) the organic compound having a hydroxyl group to (B) the unsaturated carboxylic acid or (C) the epoxy compound is usually (A) /
The molar ratio of (B) or (A) / (C) should be in the range of 0.5 to 2, preferably 0.8 to 1.2.

The amount of the rare earth element compound to be used is at least 0.5 molar equivalent to the organic compound having a hydroxyl group.
Preferably, it is used in a ratio of 0.5 to 1.5 molar equivalents.

When the etherification reaction is completed, the organic compound having a hydroxyl group and the unsaturated carboxylic acid compound or epoxy compound as a starting material are consumed, and the reaction liquid mainly contains a rare earth element salt of ether carboxylic acid.

According to the method of the present invention, an alkali metal hydroxide, for example, sodium hydroxide, potassium hydroxide or the like, preferably sodium hydroxide is added to the reaction solution after the completion of the above reaction, and the rare earth element in the reaction solution is added. Converts elemental ions to hydroxide. The addition amount of the alkali metal hydroxide may be an amount sufficient to convert rare earth element ions to hydroxide,
The specific amount can be easily determined from the amount of rare earth element ions used. In this case, it is preferable to add an alkali metal hydroxide in such an amount that the pH of the reaction solution is at least 9, especially 10 to 14.

Rare earth element hydroxides are hardly soluble in neutral or alkaline aqueous solutions containing an alkali metal salt of ether carboxylate, which is a reaction product, and are easily dissolved by ordinary separation means such as filtration. Can be separated from

The reaction solution from which the rare earth element hydroxide was separated was
It may be used as it is as an aqueous solution of an alkali metal salt of an ether carboxylic acid, or water may be distilled off to obtain a powder of an alkali metal salt of an ether carboxylic acid, which can be appropriately determined depending on the use. For example, when using sodium ether carboxylate as a detergent builder, it can be used in any form, either as an aqueous solution or as a powder.

On the other hand, as described above, the rare earth element hydroxide separated from the above reaction solution is acidic, that is, dissolved in an aqueous solution having a pH of <7 to become rare earth element ions. It can be used as a source of elemental ions.

When the recovered rare earth element hydroxide is reused as a source of rare earth element ions, the rare earth element hydroxide is converted into an organic compound having a hydroxyl group and an unsaturated carboxylic acid compound or epoxy compound in an aqueous medium. At least one of the compounds may be dissolved and dissolved in a state adjusted to acidic (pH <7).

Specifically, a rare earth element hydroxide and at least one of an organic compound having a hydroxyl group and an unsaturated carboxylic acid compound or an epoxy compound are added to an aqueous medium, and the mixture is heated if necessary. It may be dissolved by stirring. Usually, a rare earth element hydroxide, an organic compound having a hydroxyl group, and an unsaturated carboxylic acid compound or an epoxy compound are added to an aqueous medium, and the mixture is stirred and dissolved. In addition, there is no restriction | limiting in the addition order of each component, It can determine suitably.

Thereafter, as described above, the pH of the aqueous solution in which the rare earth element hydroxide and the starting material are dissolved is adjusted to 6 to 6.
After adjusting to 9, preferably 7 to 8, the etherification reaction is repeated.

The alkali metal ether carboxylate, especially the sodium salt, obtained by the method of the present invention is useful as a detergent builder as described above, and can be used in various detergent compositions. In addition, it can be used as a chelating agent.

[0082]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 After dissolving 9.8 g of maleic anhydride in 100 g of water, 7.6 g of glycolic acid was added.
2.0 g was added (around pH 7). 18.6 g of lanthanum chloride heptahydrate was added to this solution, and the pH was adjusted to 7.5 with sodium hydroxide, followed by stirring at 90 ° C. for 5 hours. After completion of the reaction, 6.0 g of sodium hydroxide was added, and the mixture was stirred for 30 minutes. Then, the reaction solution was filtered, and the filtrate was analyzed by high performance liquid chromatography. As a result, trisodium carboxymethoxysuccinate (CMOS-3) was used.
It was found that Na) was obtained in a yield of 86.8 mol%. The compound was identified by ¹ H-NMR and ¹³ C-N
Performed by MR. Further, as a result of analyzing the filtrate by ICP, the concentration of lanthanum ions in the filtrate was 3 ppm or less.

After the completion of the reaction, the solid
After charging into a one-necked flask and further adding water 100, 9.8 g of maleic anhydride and 7.6 g of glycolic acid were added. After stirring for 30 minutes, the pH was adjusted to 7.5 with sodium hydroxide, and the reaction was performed at 90 ° C. for 5 hours. After completion of the reaction, the same operation as above was performed. As a result, the yield of CMOS-3Na was 86.2 mol%, and the concentration of lanthanum ions in the filtrate was 3 ppm or less.

Example 2 After dissolving 9.8 g of maleic anhydride in 100 g of water, 7.6 g of glycolic acid was added.
2.0 g was added (around pH 7). 17.9 g of neodymium chloride hexahydrate was added to this solution, and the pH was adjusted to 7.5 with sodium hydroxide, followed by stirring at 90 ° C. for 5 hours. After completion of the reaction, 6.0 g of sodium hydroxide was added, and the mixture was stirred for 30 minutes. Then, the reaction solution was filtered, and the filtrate was analyzed by high performance liquid chromatography. As a result, trisodium carboxymethoxysuccinate (CMOS-3) was used.
It was found that Na) was obtained in a yield of 84.2 mol%. The compound was identified by ¹ H-NMR and ¹³ C-N
Performed by MR. Further, as a result of analyzing the filtrate by ICP, the concentration of neodymium ions in the filtrate was 5 ppm or less.

After the completion of the reaction, the solid
After charging into a one-necked flask and further adding water 100, 9.8 g of maleic anhydride and 7.6 g of glycolic acid were added. After stirring for 30 minutes, the pH was adjusted to 7.5 with sodium hydroxide, and the reaction was performed at 90 ° C. for 5 hours. After completion of the reaction, the same operation as above was performed. As a result, the yield of CMOS-3Na was 83.4 mol%, and the concentration of neodymium ions in the filtrate was 5 ppm or less.

[0087]

According to the method of the present invention, rare earth element ions used as a catalyst can be efficiently recovered and reused as a catalyst.

Therefore, when an organic compound having a hydroxyl group is reacted with an unsaturated carboxylic acid compound or an epoxy compound on an industrial scale to produce the corresponding alkali metal ether carboxylate, the production cost is reduced. Can be done.

Claims (2)

[Claims] 1. An organic compound having a hydroxyl group is reacted with an unsaturated carboxylic acid compound or an epoxy compound in an aqueous medium in the presence of an alkali metal ion and a rare earth element ion as a catalyst to form an alkali metal ether carboxylate. In the production method, after the reaction is completed, an alkali metal hydroxide is added, and a rare earth element ion in the reaction solution is separated and recovered as a rare earth element hydroxide. Method. 2. A method for producing an alkali metal ether carboxylate, wherein the rare earth element hydroxide separated and recovered by the production method according to claim 1 is reused as a catalyst.