JPH0931193A - Method for producing polyaspartic acid alkali metal salt and derivative thereof - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide a method for producing a polyaspartic acid alkali metal salt by using maleic acid and ammonia, or an analog derived from them as a part of raw materials, without causing decarboxylation during polymerization, and in a single step. provide. SOLUTION: Maleic acid or fumaric acid monoammonium monoalkali metal salt, maleic acid or fumaric acid monoamide monoalkali metal salt, or a mixture thereof, or maleic anhydride, maleic acid or fumaric acid and ammonia and basic alkali. A mixture obtained from a metal compound as a raw material, in which the molar ratio of maleic acid or fumaric acid skeleton to ammonium ion or amide group to alkali metal ion is 1: 0.7.
~ 1.3: What is in the range of 0.7 to 1.3 is heated and polymerized to produce an alkali metal polyaspartic acid salt.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a monoammonium monoalkali metal salt of maleic acid or fumaric acid,
Maleic acid or fumaric acid monoamide monoalkali metal salt, or a mixture thereof, or a mixture obtained by using maleic anhydride, maleic acid or fumaric acid and ammonia and a basic alkali metal compound as raw materials,
Among them, those having a maleic acid or fumaric acid skeleton and those having a molar ratio of ammonium ion or amide group to alkali metal ion in the range of 1: 0.7 to 1.3: 0.7 to 1.3 are directly used as polyaspartic acid alkali metal salt. The present invention is also intended to produce a derivative thereof from the polyaspartic acid alkali metal salt. Polyaspartic acid and its alkali metal salts are important polymers because they have applications such as cleaning additives, sequestering agents and corrosion inhibitors.

[0002]

2. Description of the Related Art As a method for producing polyaspartic acid and its derivatives, a method by heating poly (aspartic acid) to form a peptide bond has been known (J. Or.
g. Chem. 26, 1084 (1961)). On the other hand, a method is known in which maleic anhydride, maleic acid, or the like, which is more easily available, and ammonia, or a derivative easily obtained from them is used as a raw material. The Journal of Organic Chemistry (J. Org. Chem.,) 24, 1
Page 662 (1959) shows that polysuccinimide can be obtained by heating maleamic acid. JP-A-61-218634
Then, microwave polymerization of monoammonium malate, monoammonium maleate and ammonium maleamate to give anhydropolyaspartic acid (ie polysuccinimide), which is hydrolyzed with an alkali to give poly It illustrates a method of obtaining polyaspartic acid by converting to aspartate and acid treatment.

In US Pat. No. 5,219,952 (1993), polysuccinimide is obtained in high yield when maleic anhydride and ammonia are heated to a high temperature, and can be hydrolyzed with a base to give polyaspartic acid. It is described that a polysuccinimide having a high molecular weight can be obtained by adding a separately prepared polysuccinimide to an adduct of maleic anhydride and ammonia and raising the temperature to a high temperature. U.S. Pat.No. 5,288,78
3 (1994), maleic acid and ammonia are reacted at a specific molar ratio, temperature and time, and the produced polysuccinimide is hydrolyzed with an alkaline earth metal or alkali metal hydroxide or ammonium hydroxide. Disclosed is the salt of polyaspartic acid. Further, JP-A-6-248075, JP-A-6-256504 and JP-A-6-298930.
Then, maleic anhydride and ammonia, or maleic anhydride and ammonia and water, or analogs obtained from them are thermally polymerized under specific conditions to produce polysuccinimide, which may be hydrolyzed. A method for producing polyaspartic acid or a salt thereof is disclosed. In Japanese Patent Laid-Open No. 6-298930, the polymerization reaction is made into a polymer by adding an amide group of maleamic acid formed from maleic anhydride and ammonia to a double bond of a maleic acid skeleton, and then polysuccinimide is converted into a polysuccinimide by a dehydration reaction. It states that it will generate.

[0004]

The polymer obtained by thermal polymerization of maleic acid and ammonia or an analog derived from them is polysuccinimide. As described above, when an alkali metal salt of polyaspartic acid or polyaspartic acid which is important for use is desired, it is necessary to hydrolyze the produced polysuccinimide again. Therefore, it is necessary to select the conditions such that the reaction is multi-stage and the peptide bond of the main chain of polyaspartic acid formed in the hydrolysis stage is not hydrolyzed. Furthermore, in the thermal polymerization of maleic acids and ammonia or analogs derived from them, there are a large amount of carboxylic acid groups that are neither salts nor amides, but when this is heated to high temperatures, decarboxylation occurs. It has been observed that the ratio of carbon atoms to nitrogen atoms is low in elemental analysis of the produced polymer.

The object of the present invention is to use maleic acid and ammonia or an analog derived from them as a part of the raw materials, but the effect of not producing decarboxylation during polymerization and producing a polyaspartic acid alkali metal salt in a single step. To provide an effective method.

[0006]

The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, maleic acid or fumaric acid monoammonium monoalkali metal salt, maleic acid or fumaric acid monoamide. Monoalkali metal salt, or mixture thereof, or mixture obtained from maleic anhydride, maleic acid or fumaric acid and ammonia and basic alkali metal compound as raw materials, wherein maleic acid or fumaric acid skeleton and ammonium are present It was found that heating of a compound having a molar ratio of ion or amide group to alkali metal ion in the range of 1: 0.7 to 1.3: 0.7 to 1.3 can suppress decarboxylation and obtain a polyaspartic acid alkali metal salt in a single step, If necessary, the obtained polyaspartic acid alkali metal salt can be easily used for polycondensation. They have found that they can be converted to aspartic acid and polysuccinimide, and completed the present invention.

That is, the present invention relates to a monoammonium monoalkali metal salt of maleic acid or fumaric acid, a monoamide monoalkali metal salt of maleic acid or fumaric acid, or a mixture thereof, or maleic anhydride.
A mixture obtained by using maleic acid or fumaric acid, ammonia and a basic alkali metal compound as a raw material, in which the molar ratio of maleic acid or fumaric acid skeleton to ammonium ion or amide group to alkali metal ion is 1: 0.7. ~ 1.3: A method for producing an alkali metal salt of polyaspartic acid, which comprises heating in the range of 0.7 to 1.3.

Further, the present invention is a method for producing polyaspartic acid, which comprises treating the alkali metal polyaspartic acid salt obtained by this method with an acid to convert it into polyaspartic acid.

Further, the present invention is a method for producing polysuccinimide, which comprises subjecting the polyaspartic acid to dehydration cyclization by heating to convert it into polysuccinimide.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A monoammonium monoalkali metal salt of maleic acid or fumaric acid, a monoamide monoalkali metal salt of maleic acid or fumaric acid, or a mixture thereof, or maleic anhydride, which is a raw material of the method of the present invention, A mixture obtained by using maleic acid or fumaric acid, ammonia and a basic alkali metal compound as a raw material, in which the molar ratio of maleic acid or fumaric acid skeleton to ammonium ion or amide group to alkali metal ion is 1: 0.7. .About.1.3: Those in the range of 0.7 to 1.3 are easily derived by a conventional method from maleic anhydride, maleic acid or fumaric acid, ammonia and a basic alkali metal compound.

The latter () is a mixture of maleic anhydride, maleic acid or fumaric acid and ammonia in a molar ratio of 1: 0.7 to 2.5, and then a molar ratio (relative to maleic anhydride, maleic acid or fumaric acid) of 0.7 to 2.5. The method of adding a basic alkali metal compound of 1.3, or vice versa, after mixing maleic anhydride, maleic acid or fumaric acid and a basic alkali metal compound in a molar ratio of 1: 0.7 to 1.3, a molar ratio (maleic anhydride, 0.7-2.5 (relative to maleic acid or fumaric acid)
Aeration to the mixture obtained by the method of adding ammonia,
By heating or concentrating, the molar ratio of maleic acid or fumaric acid skeleton to ammonium ion or amide group to alkali metal ion is 1: 0.7 to 1.3.
: It can be obtained by preparing it in the range of 0.7 to 1.3. This molar ratio is preferably 1: 0.9 to 1.1: 0.9.
~ 1.1. The maleic acid used also includes those obtained by mixing maleic anhydride and water. As ammonia, gaseous or liquid ammonia and / or aqueous ammonia solution is used depending on the case.

The alkali metal contained in the monoammonium monoalkali metal salt of maleic acid or fumaric acid, the monoamide monoalkali metal salt of maleic acid or fumaric acid, or a mixture thereof of the present invention includes lithium, sodium, potassium, rubidium and It may be selected from cesium and may be one kind or a combination of two or more kinds. Preferred is sodium or potassium. Further, a mixture obtained by using maleic anhydride, maleic acid or fumaric acid and ammonia and a basic alkali metal compound as a raw material, in which a maleic acid or fumaric acid skeleton is contained, and an ammonium ion or an amide group and an alkali metal ion are mixed. The ratio is 1: 0.7 to 1.3:
The basic alkali metal compound for obtaining the compound having a range of 0.7 to 1.3 is selected from basic compounds of lithium, sodium, potassium, rubidium and cesium, and may be one kind or a combination of two or more kinds.
Examples of such compounds include hydroxides, carbonates and hydrogen carbonates of these alkali metals, salts of weak acids such as formic acid and acetic acid, and alkoxides.

Of these, alkali metal hydroxides, carbonates, hydrogen carbonates or alkoxides of alcohols having 1 to 3 carbon atoms are preferred, and sodium or potassium hydroxides, carbonates, It is a hydrogen carbonate or an alkoxide of an alcohol having 1 to 3 carbon atoms.

The raw material thus prepared is heated to polymerize it. In the polymerization reaction, the raw material may be solid or dissolved or suspended in a solvent. As the solvent when used, any solvent may be used as long as it does not inhibit the polymerization reaction, but they include water, for example, heptane, 2,
2,5-trimethylhexane, dodecane, cyclohexane,
saturated aliphatic or cycloaliphatic hydrocarbons such as p-menthane or decalin, unsubstituted or alkyl substituted aromatic carbons such as benzene, toluene, xylene, diethylbenzene, cumene, cymene, biphenyl, naphthalene or tetralin Hydrogen, for example, hexachloroethane, chlorobenzene, halogenated hydrocarbons such as o-dichlorobenzene or p-chlorotoluene, for example, dibutyl ether, tetrahydrofuran, anisole, benzyl ethyl ether, diphenyl ether, diethylene glycol dimethyl ether, polyethylene glycol, Ethers such as polypropylene glycol or ethylene glycol propylene glycol copolymers, such as acetonitrile, propionitrile or benzonitrile A nitrile such as Lil,
Tertiary amines such as triethylamine or N, N-dimethylaniline such as pyridine, picoline,
Pyridines such as lutidine or quinoline, such as N, N-dimethylformamide, N-methylpyrrolidone, tetramethylurea, aprotic polar solvents such as 1,3-dimethyl-2-imidazolidinone or dimethylsulfoxide, etc. Can be mentioned. These solvents may be used alone or in combination of two or more.

In the method of the present invention, the polymerization reaction can be carried out in the presence of a radical inhibitor. Examples of such radical inhibitors include 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butyl.
Monophenols such as 4-hydroxymethylphenol, 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid alkyl ester or N-lauroyl-p-aminophenol, 2,2 ' -Methylenebis (4
-Methyl-6-tert-butylphenol) or N, N '
-Hexamethylenebis (3,5-di-tert-butyl-4-
Bisphenols such as (hydroxyhydrocinnamic acid amide), hydroquinones, hydroquinones such as 2,5-di-tertiary amylhydroquinone or tertiary butylhydroquinone, and catechols such as 4-tertiarybutylcatechol, N-phenyl
-1-naphthylamine or aromatic amines such as N, N'-diphenyl-p-phenylenediamine.

In the polymerization reaction of the method of the present invention, the raw materials are heated to a high temperature, and the heating temperature is usually 350 ° C. or lower, preferably 90 to 300 ° C., more preferably 110 to 250 ° C. It is a range. The reaction time is usually within 24 hours, preferably 0.05 to 15 hours, more preferably 0.2 to 8 hours. The polymerization reaction may be carried out at any of normal pressure, increased pressure and reduced pressure depending on the case. The atmosphere of the polymerization reaction may be air or an inert gas such as nitrogen or carbon dioxide. The reaction may be carried out batchwise, semi-batchly or continuously.

According to the method of the present invention, the alkali metal polyaspartic acid salt formed after the completion of the reaction can be taken out by a conventional method. The method depends on whether a solvent is used in the polymerization reaction or not. When used, it depends on whether the produced polyaspartic acid alkali metal salt is dissolved or insoluble in a solvent. If no solvent was used in the polymerization reaction,
The produced alkali metal polyaspartic acid salt is obtained as a solid containing only it, and the alkali metal polyaspartic acid salt can be obtained without any special isolation procedure. When all or most of the formed alkali metal polyaspartic acid salt is insoluble or hardly soluble in the solvent used, it is taken out by a conventional solid-liquid separation method such as filtration, centrifugation or decantation. be able to. Further, when all or most of the formed polyaspartic acid alkali metal salt is dissolved in a solvent to form a solution, the solvent can be evaporated from the solution to dryness and taken out. The solution can be concentrated or mixed with an insoluble solvent to precipitate a solid, and then can be taken out by a conventional solid-liquid separation method such as filtration, centrifugation or decantation. The thus-removed alkali metal polyaspartic acid salt can be optionally purified by a conventional polymer purification method such as reprecipitation or membrane separation.

The polyaspartic acid alkali metal salt obtained by the method of the present invention is treated with an acid to convert it into polyaspartic acid, and optionally, the polyaspartic acid is further dehydrated and cyclized by heating. It can be converted to polysuccinimide.

As the acid treatment for converting the polyaspartic acid alkali metal salt obtained by the method of the present invention into polyaspartic acid, a general method for obtaining a carboxylic acid from a general carboxylic acid alkali metal salt is used. Any method may be used as long as it effectively contacts the alkali metal aspartic acid salt and the acid. Depending on the case, the polymerization reaction system from which the polyaspartic acid alkali metal salt is obtained can be directly subjected to an acid treatment, or the obtained polyaspartic acid alkali metal salt is once separated by the above-mentioned method and then acidified again. It can also be processed. The acid used for the acid treatment is, for example, a mineral acid such as hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid, or a proton type cation exchange resin. The acid treatment is usually performed in the presence of a solvent. Examples of such a solvent include, among the solvents used in the polymerization reaction, water, saturated aliphatic or alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ethers,
Examples thereof include nitriles and aprotic polar solvents, and further examples include alcohols having 1 to 4 carbon atoms such as methanol, ethanol and n-butanol.
The solvent may be used alone or in combination of two or more kinds.

After completion of the acid treatment, when the produced polyaspartic acid is precipitated as a solid, it can be taken out by a usual solid-liquid separation method such as filtration, centrifugation or decantation. If it is dissolved in the solvent used, evaporate it to dryness and remove it, or concentrate it or mix it with a solvent that is difficult to dissolve to precipitate a solid, and use a normal solid-liquid solution such as filtration, centrifugation or decantation. It can be taken out by a method of separation.

When the polyaspartic acid thus taken out contains an alkali metal salt of a mineral acid, the alkali metal salt of the mineral acid should be removed by a method such as dialysis or membrane separation. You can also Further, when it is desired to convert the polyaspartic acid by heating to dehydrate cyclize to convert into polysuccinimide, the polyaspartic acid is subjected to a dehydration cyclization reaction without removing the alkali metal salt of the mineral acid, and after completion of the reaction, the metal of the mineral acid is removed. The salt can also be separated and removed from the polysuccinimide, for example by washing with water.

In the method of the present invention, the obtained polyaspartic acid can be converted into polysuccinimide by heating and cyclodehydration. Any method may be used as the method for heat dehydration cyclization as long as the polyaspartic acid is efficiently heated. The heating of the polyaspartic acid may be carried out as it is as a solid or after it is dissolved or suspended in a solvent. As the solvent when used, any solvent may be used as long as it does not inhibit the dehydration cyclization reaction of polyasparaquinic acid, and as such a solvent, for example, among the solvents used in the polymerization reaction, Examples thereof include saturated aliphatic or alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ethers, nitriles, and aprotic polar solvents.

The heating temperature is usually 350 ° C. or lower,
It is preferably in the range of 90 to 300 ° C, and more preferably in the range of 110 to 250 ° C. The reaction time is usually within 24 hours, preferably 0.05 to 15 hours, more preferably 0.2 to 8 hours. The dehydration cyclization reaction can be carried out at any of normal pressure, increased pressure and reduced pressure depending on the case. The reaction atmosphere may be air or an inert gas such as nitrogen or carbon dioxide. The reaction may be carried out batchwise, semi-batchly or continuously.

The produced polysuccinimide can be obtained as a solid without any particular isolation operation if a solvent is not used. Even if a solvent is used, the polysuccinimide is solid in the solvent. If it is present, it can be taken out by a usual solid-liquid separation method such as filtration, centrifugation or decantation, and if it is dissolved in the solvent, the solvent is evaporated from the solution to dryness. It can be taken out, or the solution can be taken out by a conventional solid-liquid separation method such as filtration, centrifugation or decantation after the solution is concentrated or mixed with a solvent which is difficult to dissolve to precipitate a solid.

[0025]

The following examples further illustrate the present invention, but are not to be construed as limiting, but merely as illustrative. Example 1 A 200 ml three-necked eggplant-shaped flask was charged with 17.36 g of a 10 wt% sodium hydroxide aqueous solution (43.4 mmol as sodium hydroxide), and 5.00 g (43.4 mmol) of powdery maleamic acid at room temperature while stirring. )
Was added in small portions. The added maleamic acid dissolved immediately. A colorless transparent solution was obtained. This solution was immersed in a water bath at 60 ° C., water was distilled off under reduced pressure of 40 mmHg, and the obtained solid was further dried under reduced pressure at 1 mmHg for 3 hours to obtain a white solid. (Separately obtained white solid was confirmed to be maleamic acid sodium salt as a result of measuring elemental analysis, sodium analysis by atomic absorption method and ¹ H-NMR).

Next, the inside of the flask was replaced with nitrogen, and the maleamic acid sodium salt was immersed in an oil bath at 170 ° C. and heated for 5 hours to polymerize the maleamic acid sodium salt. At the start of the reaction, the white solid gradually became brown as the reaction proceeded. After the reaction was completed, 5.87 g of a yellowish brown solid was obtained. The solid result of the elemental analysis of very good agreement with the calculated value of the polyaspartic acid sodium salt, ¹ H
When -NMR and ¹³ C-NMR were measured, it was confirmed that the polysuccinimide obtained by polycondensation of aspartic acid was hydrolyzed with an aqueous solution of sodium hydroxide to confirm that it was identical with the spectrum of the standard polyaspartic acid sodium salt. However, it was found that this solid was polyaspartic acid sodium salt. The molar yield of polyaspartic acid sodium salt was 98.6% (based on maleamic acid). As a result of measuring the molecular weight by gel filtration chromatography,
The weight average molecular weight was 4,400 based on pullulan. From the results of elemental analysis, it was found that the polyaspartic acid sodium salt obtained by this method had an atomic ratio of carbon atoms and nitrogen atoms of 4.03 in C / N. This value agrees with a theoretical value of C / N of 4, and when polyaspartic acid sodium salt was synthesized using maleamic acid sodium salt as a raw material, the polymerization reaction proceeded without decarboxylation. It became clear.

Comparative Example 1 Maleamic acid was directly subjected to a polymerization reaction without being converted into a sodium salt. A polymerization reaction was performed in the same manner as in Example 1 except that 5.00 g (43.4 mmol) of maleamic acid was used instead of the maleamic acid sodium salt. At the start of the reaction, the white solid gradually became reddish brown as the reaction proceeded. Further, generation of water vapor from the reaction product was recognized. After the reaction was completed, 3.83 g of a reddish brown solid was obtained. ¹ H-NMR and ¹³ C-NM
When R was measured, this solid was polysuccinimide. The molar yield of polysuccinimide was 90.8%. As a result of measuring the molecular weight of this polysuccinimide by gel filtration chromatography, the weight average molecular weight was 3100 based on polystyrene. In addition, elemental analysis revealed that the polysuccinimide obtained by this method had an atomic ratio of carbon atoms to nitrogen atoms of 3.62 in C / N. This value indicates that the number of carbon atoms is reduced because the number of nitrogen atoms does not increase when compared with C / N, which is the theoretical value of polysuccinimide, of 4, and polysuccinimide is used with maleamic acid as a raw material. It is clear that decarboxylation occurs when the acid imide is synthesized.

Example 2 Reaction and post-treatment were carried out in the same manner as in Example 1 to synthesize maleamic acid sodium salt. Next, 100 g of ethylene glycol propylene glycol copolymer (polyether EP-505S manufactured by Chiba Polyol Co., Ltd.) was added to this maleamic acid sodium salt as a solvent. After replacing the inside of the flask with nitrogen, heat at 190 ° C. for 5 hours,
Polymerization reaction of maleamic acid sodium salt was performed. At the start of the reaction, a white solid was suspended in the solvent, but as the reaction proceeded, polyaspartic acid sodium salt became a yellowish brown solid and became suspended in the solvent. After completion of the reaction, the reaction mixture was cooled to 80 ° C., the solid was filtered while hot, washed with a small amount of methanol, and dried under reduced pressure to obtain 5.73 g of sodium polyaspartic acid salt. The molar yield of polyaspartic acid sodium salt was 96.2%, and the weight average molecular weight was 48.
00, C / N ratio was 4.04.

Example 3 Reaction and post-treatment were carried out in the same manner as in Example 1 to synthesize maleamic acid sodium salt. Then, 100 g of cumene as a solvent was added to this maleamic acid sodium salt, and the mixture was heated at 150 ° C. for 5 hours to polymerize the maleamic acid sodium salt. Polyaspartic acid sodium salt formed as a tan solid. After completion of the reaction, the reaction mixture was cooled to room temperature, the solid was filtered, washed with a small amount of methanol and dried under reduced pressure to obtain 5.84 g of sodium polyaspartic acid salt. The molar yield of polyaspartic acid sodium salt is 98.1%,
The weight average molecular weight was 3,600. The C / N ratio was 3.99.

Example 4 The same reaction and post-treatment as in Example 1 were carried out to synthesize maleamic acid sodium salt. Next, this maleamic acid sodium salt was added with o-dichlorobenzene 100 as a solvent.
g was added. The mixture was heated at 170 ° C. for 5 hours to carry out a polymerization reaction of maleamic acid sodium salt. Polyaspartic acid sodium salt formed as a tan solid. After completion of the reaction, the reaction mixture was cooled to room temperature, the solid was filtered, washed with a small amount of methanol and dried under reduced pressure to obtain 5.85 g of sodium polyaspartic acid salt.
The molar yield of polyaspartic acid sodium salt is 98.2.
%, The weight average molecular weight was 5100, and the C / N ratio was 4.02.

Example 5 A 200 ml three-necked eggplant-shaped flask was charged with 69.51 g of a 10% by weight aqueous sodium hydroxide solution (173.8 mmol as sodium hydroxide), and 20.00 g of powdered maleamic acid (at room temperature while stirring) 173.8 mm
ol) was added little by little. The added maleamic acid dissolved immediately. A colorless and transparent aqueous solution of maleamic acid sodium salt was obtained. Immerse this solution in a water bath at 60 ° C.
The solution was concentrated under reduced pressure of mmHg until the weight of the aqueous solution reached 32.0 g. This aqueous solution contains 23.8 g of maleamic acid sodium salt. Thus, an aqueous solution of maleamic acid sodium salt was prepared.

Then, 70 ml of this maleic acid sodium salt aqueous solution was charged into an autoclave, the inside of the reactor was replaced with nitrogen, and then the mixture was heated at 200 ° C. for 5 hours to carry out a polymerization reaction of the maleamic acid sodium salt. When the autoclave was opened after completion of the reaction, the reaction mixture became a highly viscous brown liquid. After 50 g of water was added to the reaction mixture to dilute it, the aqueous solution was dropped into 400 g of ethanol, whereby polyaspartic acid sodium salt was precipitated as a brown solid. This solid was filtered, washed with a small amount of ethanol, and dried under reduced pressure to obtain 21.7 g of sodium polyaspartic acid salt. The yield of sodium polyaspartic acid salt was 91.1%, and the weight average molecular weight was 5,300. The C / N ratio was 4.02.

Example 6 A 200 ml three-necked eggplant-shaped flask was charged with 4.35 g (43.4 mmol) of potassium hydrogencarbonate and 20 g of water to prepare an aqueous potassium hydrogencarbonate solution. 0.00 g (43.4 mmo
l) was added in small portions. The added maleamic acid immediately dissolved, and carbon dioxide gas was observed to be generated, and a colorless transparent solution was obtained. Dip this solution in a water bath at 60 ° C for 40 mm
Water was distilled off under reduced pressure of Hg, and the resulting solid was further removed by 1 mm.
A white solid was obtained by drying under reduced pressure with Hg for 3 hours.
Separately, the white solid obtained in exactly the same manner was confirmed to be maleamic acid potassium salt as a result of measuring elemental analysis, potassium absorption by atomic absorption method and ¹ H-NMR.

Next, this potassium maleamic acid salt was added with 7 m of tertiary butyl catechol as a radical inhibitor.
After adding g (0.042 mmol) and replacing the inside of the flask with nitrogen, the flask was immersed in an oil bath at 180 ° C. and heated for 3.5 hours to carry out a polymerization reaction of potassium maleamic acid salt.
At the start of the reaction, the white solid gradually became brown as the reaction proceeded. After the reaction was completed, 6.52 g of a brown solid was obtained. When the elemental analysis of this solid was measured, it was in good agreement with the calculated value of polyaspartic acid potassium salt, and further ¹ H-NMR and ¹³ C-NMR were measured to find that polysuccinimide obtained by polycondensation of aspartic acid was It was confirmed that this solid was polyaspartic acid potassium salt, in agreement with the spectrum of the standard product of potassium polyaspartic acid salt obtained by hydrolysis with an aqueous solution of potassium hydroxide. The molar yield of potassium polyaspartic acid salt was 98.0%, and the weight average molecular weight was 3,500. The C / N ratio was 3.98.

Example 7 Maleic anhydride 5.00 g in a 200 ml three-necked flask
(51.0 mmol) and 5 g of water were charged, and the mixture was heated at 60 ° C.
After heating for a minute, it was cooled to room temperature. 2 at room temperature in this solution
10.20 g of 0% sodium hydroxide aqueous solution (51.0 mmol as sodium hydroxide) was added dropwise over 10 minutes, and then 3.18 g of 30% aqueous ammonia (56.0 mmol as ammonia) was added dropwise over 5 minutes. The molar ratio of the charged maleic anhydride, ammonia and sodium hydroxide is 1: 1.1: 1. After the dropwise addition of aqueous ammonia, a colorless transparent solution was obtained. This solution was immersed in a water bath at 60 ° C., water was distilled off under reduced pressure of 40 mmHg, and the obtained solid was further dried under reduced pressure at 1 mmHg for 3 hours to obtain a white solid. Take a very small amount of this white solid,
As a result of elemental analysis and sodium analysis by atomic absorption spectrometry, it was found that this white solid was a mixture in which the molar ratio of maleic acid skeleton, ammonium ion and sodium ion was 1: 0.93: 1.0.

Next, 6 mg (0.054 mmol) of hydroquinone as a radical inhibitor was added to this mixture, and the inside of the flask was replaced with nitrogen, and then 100 to 110 ° C.
For 30 minutes and then at 200 ° C. for 5 hours to carry out a polymerization reaction. At the start of the reaction, the white solid gradually became brown as the reaction proceeded. After the reaction was completed, 6.31 g of a light brown solid was obtained. ¹ of this solid
H-NMR and ¹³ C-NMR were measured to find that the spectrum of a standard polyaspartic acid sodium salt obtained by hydrolyzing polysuccinimide obtained by polycondensation of aspartic acid with an aqueous sodium hydroxide solution. In agreement, this solid was confirmed to be polyaspartic acid sodium salt. The molar yield of polyaspartic acid sodium salt was 90.3%, and the weight average molecular weight was 41.
It was 00. The C / N ratio was 4.04.

Example 8 Reaction and post-treatment were carried out in the same manner as in Example 7 to synthesize a mixture in which the molar ratio of maleic acid skeleton, ammonium ion and sodium ion was 1: 0.93: 1.0.

Next, 100 g of o-dichlorobenzene as a solvent and 6 mg (0.054 mmol) of hydroquinone as a radical inhibitor were added to a flask containing this mixture, and the inside of the flask was replaced with nitrogen, and then 100 to 110 ° C.
For 30 minutes and then at 170 ° C. for 5 hours to carry out a polymerization reaction. Polyaspartic acid sodium salt formed as a light brown solid. After completion of the reaction, the reaction mixture was cooled to room temperature, the solid was filtered, washed with a small amount of methanol and dried under reduced pressure to obtain 6.28 g of sodium polyaspartic acid salt. The molar yield of polyaspartic acid sodium salt was 90.0%, and the weight average molecular weight was 3
At 700, the C / N ratio was 3.97.

Example 9 Maleic anhydride 5.00 g in a 200 ml three-necked flask
(51.0 mmol) and 5 g of water were charged, and the mixture was heated at 60 ° C.
After heating for a minute, it was cooled to room temperature. Add 3 to this solution at room temperature.
5.79 g of 0% ammonia water (10 as ammonia)
2.0 mmol) over 7 minutes, then 20%
10.20 g of sodium hydroxide aqueous solution (51.0 mmol as sodium hydroxide) was added dropwise over 10 minutes. The molar ratio of the charged maleic anhydride, ammonia and sodium hydroxide is 1: 2: 1. After the dropwise addition of the aqueous sodium hydroxide solution, a colorless transparent solution was obtained. This solution was immersed in a water bath at 60 ° C., water was distilled off under reduced pressure of 40 mmHg, and the obtained solid was further dried under reduced pressure at 1 mmHg for 3 hours to obtain a white solid. As a result of elemental analysis and sodium analysis by atomic absorption spectrometry, a small portion of this white solid was taken, and as a result, the white solid had a molar ratio of maleic acid skeleton, ammonium ion and sodium ion of 1
: 0.97: 1.0 was found to be a mixture. Excess ammonia was distilled off with water.

Next, 6 mg (0.054 mmol) of hydroquinone as a radical inhibitor was added to this mixture, and the inside of the flask was replaced with nitrogen, and then 100 to 110 ° C.
For 30 minutes and then at 200 ° C. for 5 hours to carry out a polymerization reaction. After the reaction was completed, 6.37 g of sodium polyaspartic acid salt was obtained as a light brown solid. The molar yield of sodium polyaspartic acid salt was 91.1%, the weight average molecular weight was 4200, and the C / N ratio was 4.00.

Example 10 4.0 g of polyaspartic acid sodium salt obtained in Example 1 (29.2 mmol of aspartic acid unit)
Was dissolved in 40 g of water. This aqueous solution is used as a proton type cation exchange resin (ion exchange capacity 2.0 equivalent / liter).
A column packed with 50 ml was passed through a column at room temperature for acid treatment. After the acid treatment, water was distilled off under reduced pressure, and the remaining solid was dried under reduced pressure to obtain 3.09 g of a tan solid. When this solid was subjected to sodium analysis by an atomic absorption method, sodium was not detected. Further, ¹ H-NMR and ¹³ C-NMR of this solid were measured. As a result, polysuccinimide obtained by polymerization of aspartic acid was hydrolyzed with an aqueous solution of sodium hydroxide and further treated with an acid to obtain polyasparagine. Consistent with the spectrum of the acid standard, the tan solid was polyaspartic acid.

Example 11 Polyaspartic acid 2.5 obtained in Example 10
10 ml of g (aspartic acid unit 21.7 mmol)
Put in an eggplant-shaped flask, and use an oil bath at 170 ° C for 3
After heating for an hour, a dehydration cyclization reaction of polyaspartic acid was performed. As the reaction proceeded, it was observed that water vapor was released from the reaction product. After the reaction was completed, 2.11 g of a yellowish brown solid was obtained. When ¹ H-NMR and ¹³ C-NMR of this solid were measured, it was in agreement with the spectrum of polysuccinimide obtained by polymerization of aspartic acid, and this yellow solid was polysuccinimide.

[0043]

According to the method of the present invention, a compound or mixture derived from maleic anhydride, maleic acid or fumaric acid and ammonia and a basic alkali metal compound is heated to cause polymerization, and decarboxylation occurs during the polymerization. Moreover, the alkali metal polyaspartic acid salt can be produced in a good yield in a single step.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuji Takagi 1190, Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (10)

[Claims] 1. A monoammonium monoalkali metal salt of maleic acid or fumaric acid, a monoamide monoalkali metal salt of maleic acid or fumaric acid, or a mixture thereof, or maleic anhydride, maleic acid or fumaric acid and ammonia and basic. A mixture obtained from an alkali metal compound as a raw material, in which the molar ratio of maleic acid or fumaric acid skeleton to ammonium ion or amide group to alkali metal ion is 1: 0.7.
~ 1.3: A method for producing an alkali metal salt of polyaspartic acid, which comprises heating one in the range of 0.7 to 1.3. 2. The method according to claim 1, wherein the molar ratio of maleic acid or fumaric acid skeleton to ammonium ion or amide group to alkali metal ion is in the range of 1: 0.9 to 1.1: 0.9 to 1.1. 3. The heating temperature is 110 to 250 ° C.
The method according to claim 1 or 2, wherein 4. The alkali metal contained in the monoammonium monoalkali metal salt of maleic acid or fumaric acid, the monoamide monoalkali metal salt of maleic acid or fumaric acid, or a mixture thereof is sodium or potassium. The method according to claim 3. 5. The basic alkali metal compound is an alkali metal hydroxide, carbonate, hydrogen carbonate, or carbon number 1
The method according to any one of claims 1 to 3, which is an alkoxide of an alcohol of 3 to 3. 6. The basic alkali metal compound is sodium or potassium hydroxide, carbonate, hydrogen carbonate,
Alternatively, the method according to any one of claims 1 to 3, which is an alkoxide of an alcohol having 1 to 3 carbon atoms. 7. The method according to claim 1, wherein the heating is performed in the presence of a solvent. 8. The method according to claim 1, wherein the heating is performed in the presence of a radical inhibitor. 9. A polyaspartic acid, which is obtained by treating the alkali metal polyaspartic acid salt obtained by the method according to any one of claims 1 to 8 with an acid to convert it into polyaspartic acid. Manufacturing method. 10. A method for producing a polysuccinimide, which comprises subjecting the polyaspartic acid obtained by the method according to claim 9 to dehydration cyclization by heating to convert it into polysuccinimide.