JPH1036505A - Production of modified polyaspartic acid and water treatment agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a modified polyaspartic acid useful as an agent for preventing the attachment of a scale, sludge, etc., on a heating pipe, a heat-exchanger, a condenser, a polymerizing vessel, a piping, etc., by reacting polysuccinimide with a salt of an aminosulfonic acid and further hydrating a remaining imide ring. SOLUTION: A salt of an aminosulfonic acid is obtained by reacting polysuccinimide produced by using 0.002-0.3mol catalyst based on 1mol raw material, with an aminosulfonic acid salt such as a 2-aminoethylsulfonic acid salt, an aminomethanesulfonic acid salt and an aminobenzenesulfonic acid salt. Further, a remaining imide ring in the reaction product is hydrated to provide the objective modified polyaspartic acid useful as a water treatment agent having a high preventing ability of a scale.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a modified polyaspartic acid and its use. More specifically, the present invention relates to a method for producing polyaspartic acid into which sulfonic acid groups have been introduced, and a use as a water treatment agent. Here, the water treatment agent refers to a heating tube in a boiler system, a cooling water system, a hot water system, a dust collection water system, and the like. It is a chemical used to prevent heat transfer, condensers, polymerization tanks, pipes, and other scales from obstruction such as heat transfer inhibition, flow rate reduction, and local corrosion caused by adhesion or deposition of scale, sludge, and the like.

[0002]

2. Description of the Related Art As a modified product obtained by reacting polysuccinimide with aminosulfonic acid, US Pat.
No. 797 discloses that a modified polyaspartic acid in which a sulfonic acid group is introduced in an amount of 50 mol% or more based on an imide unit is used as a cosmetic composition. Japanese Patent Application Laid-Open No. 8-67752 discloses a method in which aminosulfonic acid is directly reacted with polysuccinimide and used as a water treatment agent. However, with this approach,
Aminosulfonic acid hardly reacts with polysuccinimide, and only poor water-treating agents have been obtained. The present invention solves the problems of the above technology, and provides a highly efficient method for producing modified polyaspartic acid having a high conversion of aminosulfonic acid and a high-performance water treatment agent.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the above-mentioned technology and to provide a production method for efficiently obtaining a modified polyaspartic acid with a high conversion of polysuccinimide to an imide ring. Is what you do. Further, the present invention provides a high-performance water treatment agent containing the modified polyaspartic acid.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems. As a result, instead of reacting polysuccinimide with aminosulfonic acid, an efficient imide is obtained by reacting a salt thereof with aminosulfonic acid. The present inventors have found that the aminosulfonation reaction of the ring is carried out and that a further modified polyaspartic acid can be obtained by further hydrolyzing the reaction product, and the present invention has been achieved. Hereinafter, the present invention will be described specifically.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION

(Polysuccinimide) The polysuccinimide used in the present invention is not particularly limited, and the polymer may contain at least 50 mol% of a succinimide unit. Polysuccinimide is obtained, for example, by polymerizing at least one monomer selected from a product obtained by reacting maleic acid and ammonia, maleamic acid and / or aspartic acid. This polymerization reaction can be usually carried out in the presence or absence of a catalyst with or without a solvent. A preferred embodiment includes, for example, a method in which aspartic acid is reacted as a monomer using a catalyst in the presence or absence of a solvent. The product obtained by reacting maleic acid with ammonia is reacted, for example, by the methods described in German Patent No. 3,626,672, US Pat. No. 4,839,461, and US Pat. No. 5,286,810. It is a product obtained by Specifically, it may contain products such as maleic acid, maleic acid diammonium salt, ammonia, fumaric acid, aspartic acid, asparagine, iminodisuccinic acid, maleamic acid and the like.

[0006] The maleic acid used in the above reaction includes its anhydride, partial and complete esters. Ammonia is used as a gas or solution. When used as a solution,
A method of dissolving in water to make an ammonium hydroxide aqueous solution,
For example, a method of dissolving in alcohol such as methanol or ethanol, or another appropriate organic solvent is used. Maleamic acid can be obtained by heating a mono- or di-ammonium maleate salt. Aspartic acid may be in D-form, L-form or a mixture thereof.
Further, other than these components, other copolymerizable monomers can be used in a range not exceeding 50 mol% of all monomers. The copolymerizable monomer is not particularly limited, and examples thereof include a) aspartate, b) glutamic acid and its salts, c) alanine, leucine, lysine, and other amino acids other than a) and b), and d) glycol. acid,
Lactic acid, hydroxycarboxylic acid such as 3-hydroxyacetic acid,
e) Compounds having one or more functional groups capable of reacting with an amino group and a carboxylic acid, such as 2-hydroxyethanol, maleic acid, 6-aminocaproic acid, and aniline, may be included.

[0007] The presence or absence of the reaction solvent is not particularly limited. When a solvent is used, examples of usable solvents include hydrocarbon solvents, halogenated hydrocarbon solvents, ether solvents,
Examples of the solvent include a solvent having a boiling point of 100 ° C. or more, which is selected from the group consisting of an ester solvent and an aprotic polar solvent, and particularly preferably have a boiling point of 130 ° C. or more. These solvents may be used alone or in combination. Specifically, as the hydrocarbon-based solvent, xylene and diethylbenzene (each of the above two kinds may be composed of a mixture of two or more kinds of isomers, even if the two kinds are composed solely of their ortho, meta or para isomers) ), Toluene, amylbenzene, cumene, mesitylene, tetralin, halogenated hydrocarbon solvents such as chlorotoluene and dichlorobenzene (each of the above two is composed solely of its ortho, meta or para isomer) Or a mixture of two or more isomers), 1,4-dichlorobutane, chlorobenzene, ether solvents such as dichloroethyl ether, butyl ether, diisoamyl ether, anisole, and ester solvents As a solvent, n-amyl acetate,
Isoamyl acetate, methyl isoamyl acetate, cyclohexyl acetate, benzyl acetate, n-butyl propionate, isoamyl propionate, isoamyl butyrate, n-butyl butyrate, aprotic polar solvents such as N, N-dimethylformamide, N, N -Dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, tetramethylurea acid, dimethylsulfoxide, sulfolane and hexamethylphosphoramide. Among these, diethylbenzene, mesitylene, cumene, chlorotoluene, 1,4-
Dichlorobutane, diisoamyl ether, n-butyl butyrate, 1,3-dimethyl-2-imidazolidinone, and sulfolane are preferable in that they have an appropriate boiling point, and mesitylene, cumene, chlorotoluene, 1,3 −
Dimethyl-2-imidazolidinone and sulfolane are particularly preferred.

The solvent is used in an amount of 1 to 100 parts by weight of the monomer.
It can be used in a proportion of up to 5000 parts by weight, preferably 5 to 4000 parts by weight, more preferably 10 to 3000 parts by weight. The presence or absence of a catalyst is not particularly limited, but it is preferable to use a catalyst. As the catalyst used, for example, an acid catalyst, sulfuric acid, sulfuric anhydride, phosphoric acid, polyphosphoric acid, metaphosphoric acid, condensed phosphoric acid, inorganic acids such as phosphoric anhydride,
Organic acids such as p-toluenesulfonic acid, trichloroacetic acid, trifluoroacetic acid, and trifluoromethanesulfonic acid are exemplified. In addition, phosphoric acid monoester, phosphoric acid diester, phosphoric acid triester and the like, preferably, phosphoric acid, polyphosphoric acid, metaphosphoric acid, condensed phosphoric acid,
Phosphoric anhydride, phosphoric acid monoester, phosphoric acid diester,
Phosphoric acid triester. Suitable amounts of these catalysts are in the range of 0.002 to 0.3 mol, preferably 0.02 to 0.25 mol, per mol of the monomer.

The reaction conditions are not particularly limited, but the reaction temperature is usually 100 to 300 ° C., preferably 13 to 30 ° C.
The range is from 0 to 280C. If the polycondensation temperature is lower than 100 ° C., the reaction does not easily proceed, and if it exceeds 300 ° C., decomposition products are generated, which is not preferable. The pressure during the reaction is not particularly limited, and may be normal pressure, reduced pressure, or increased pressure, but is preferably normal pressure or reduced pressure. Reaction time is 1
Seconds to 100 hours, preferably 10 seconds to 50 hours, most preferably 20 seconds to 10 hours. Further, the substantial end point of the reaction is a point at which the generation of water by-produced during the reaction has ceased. An amine or the like may coexist for the purpose of controlling the molecular weight during the polycondensation reaction.

The post-treatment step can be appropriately selected according to the use of the polymer. For example, it can be carried out by a conventional method such as a method of removing the solvent by centrifugation or a method of washing with water or a low boiling point solvent after centrifugation. Examples of these polycondensation reactions are described in JP-B-48-20
No. 638, US Pat. No. 4,839,461, US
No. 5,057,597, US Pat. No. 5,219,986, and EP 578,449. The molecular weight of the polysuccinimide used in the present invention is preferably 1,000 to 500,000, more preferably 1,000 to 150,000 in terms of weight average molecular weight.

(Aminosulfonate) The present invention requires that the above polysuccinimide be reacted with an aminosulfonate. The aminosulfonate used herein may have one or more primary or It is a compound having a secondary amino group and one or more sulfonate groups, and a primary amino group is particularly preferred. Specific examples thereof include 2-aminoethyl sulfonate, aminomethane sulfonate, and aminobenzene sulfonate. The salt is not particularly limited as long as it is a sulfonic acid salt, and may be a mixture of one or more salts, but is preferably an alkali metal salt, and particularly preferably a lithium, sodium, or potassium salt.

(Reaction between Polysuccinimide and Aminosulfonic Acid Salt) The reaction between polysuccinimide and aminosulfonic acid salt is not particularly limited, and is carried out in the presence or absence of a solvent. By this reaction, the imide ring in the polysuccinimide is opened to form an aminosulfonic acid salt. The reaction temperature is preferably from 0 ° C to less than 150 ° C, more preferably from 5 ° C to less than 120 ° C. When the temperature is lower than 0 ° C., the reaction does not easily proceed, and when the temperature is 150 ° C. or higher, the effect as a water treatment agent is low. The reaction time is preferably 1
Minutes to 30 days, more preferably 5 minutes to 20 days.

When a solvent is used, a solvent that dissolves polysuccinimide is preferable. Specifically, N, N-dimethylformamide, dimethylsulfoxide, N, N-
Examples include aprotic polar solvents such as dimethylacetamide, N-methylpyrrolidone, and sulfolane. The amount of the solvent used is preferably 10 to 10000 parts by weight, more preferably 20 to 100 parts by weight, based on 100 parts by weight of the polymer.
5000 parts by weight. The product can be isolated by a conventional method, and examples thereof include a method of distilling off the solvent and a method of crystallizing with a poor solvent for the polymer. The amount of the aminosulfonic acid salt introduced into the polysuccinimide is 0.1 mol% or more and less than 20 mol%, preferably 0.2 mol% or more and less than 15 mol%, based on the imide unit. When the amount of aminosulfonic acid introduced is 0.1 mol% or less or 20 mol% or more, the performance as a water treatment agent is reduced.

(Hydrolysis) The hydrolysis of polyaspartic anhydride in the method of the present invention can be carried out according to a conventional method. Am. Che
m. Soc. 80, 3361 (1958); Or
g. Chem. 26, 1084 (1961), U.S. Pat. No. 5,221,733, and U.S. Pat.
8,783 and JP-A-60-203636. For example, 50 to 1000 parts by weight of water based on 100 parts by weight of the reaction product and 0.7 to 3 moles of an alkali metal hydroxide based on 1 mole of the reaction product are mixed at 0 to 50 ° C. The reaction is preferably performed at a temperature for 10 minutes to 8 hours. Most of the imide rings remaining in the polymer are opened by this hydrolysis. The modified polyaspartic acid obtained as described above can be used for various applications, but is particularly suitable as a water treatment agent as a scaling inhibitor and exhibits an extremely excellent effect. The application of the water treatment agent includes, for example, prevention of scale adhesion in devices such as a boiler system, a cooling water system, a hot water system, and a dust collection system.

[0015]

【Example】

Production Example 1 Production of polysuccinimide Under a nitrogen gas atmosphere, L-aspartic acid (5.0 kg)
And 85% phosphoric acid (500 g) were mixed with a super mixer (manufactured by Kawata Corporation) for 5 minutes to disperse the catalyst. The polycondensation reaction is performed by S2KRC manufactured by Kurimoto Iron Works, Ltd.
Kneader (50φ × 661.5L, L / D 13.2)
Was performed as follows. The heating medium was set at 260 ° C, the screw rotation speed was set at 30 rpm, and the discharge rate was 1 kg / h.
(Average residence time 16 minutes) The above-obtained mixture of aspartic acid and phosphoric acid is supplied to perform polycondensation,
A brown powder was obtained. The resulting product was washed with water to remove phosphoric acid as a catalyst. The weight average molecular weight of this product was 17,000. However, the weight average molecular weight is TSKgelGMHHR-M + TSKgelG200 manufactured by Tosoh Corporation.
This is a polystyrene equivalent value obtained by gel permeation chromatography (differential refractometer) using a 0HHR column and dimethylformamide to which 10 mM LiBr was added as an eluent. Hereinafter, the obtained product is referred to as resin A.

The hydrolysis is carried out using a 100
A 3 cc beaker was charged with 3 g of the resin A obtained above and 10 g of water, and 1.4 g of sodium hydroxide was added to water 2 under ice cooling.
This was carried out by adding an aqueous solution dissolved in 0 g and then stirring for 1 hour. After the reaction, the reaction solution was
The solution was crystallized by pouring the mixture into 1 l, and 3.3 g of yellow-white sodium polyaspartate was obtained. Hereinafter, this polyaspartate is referred to as resin B.

Production Example 2 200 equipped with a cooler, thermometer, stirrer and water separator
25 g of aspartic acid, 85 g
% Phosphoric acid 2.5 g, mesitylene 56 g and sulfolane 24 g were charged. Subsequently, the polycondensation reaction was carried out under normal pressure under reflux of mesitylene (162 ° C.) for 4.5 hours.
The water generated during this time was distilled out of the system together with mesitylene. After completion of the reaction, the reaction mixture was filtered off, and the product was washed four times with 100 g of pure water and further washed with 100 g of methanol. The product was dried under reduced pressure at 80 ° C. for 24 hours to obtain a yellow-white powder 1.
7.9 g were obtained. The weight average molecular weight of this product measured by the same method as in Production Example 1 was 66,000. Hereinafter, the obtained product is referred to as a resin C. Hydrolysis was carried out in the same manner as in Production Example 1 except that the resin A was replaced with the resin C, to obtain 3.9 g of yellow-white sodium polyaspartate. Hereinafter, this polyaspartate is referred to as resin D.

EXAMPLE 1 Resin A (94 g) and N, N-
Dimethylformamide (400 g) was charged and resin A was dissolved. Subsequently, taurine sodium salt (sodium 2-aminoethanesulfonate) (7.1 g) was added to the reaction solution, which was then attached to a rotary evaporator set to a bath temperature of 140 ° C., and heated for 3 hours. After the reaction,
The reaction solution was dropped into methanol (5 L) to crystallize the polymer. After filtration of the mixture, the solid was washed with methanol (2 L)
Washed twice and dried under reduced pressure at 100 ° C. for 24 hours to obtain 84 g of a brown solid. Next, in order to carry out hydrolysis, 93% sodium hydroxide (40.5 g) and water (4
80 g) and sodium hydroxide was dissolved therein. After cooling the beaker with ice water, the brown solid was added little by little, and then stirred at room temperature for 1 hour. After completion of the reaction, the reaction solution was dropped into methanol (5 L) to crystallize the polymer. After filtering the mixture, the solid was removed from methanol (2 L).
And dried under reduced pressure at 50 ° C. for 24 hours to obtain 81 g of a yellow solid. Hereinafter, this product is referred to as a resin E. The resin proton NMR (dimethylsulfoxide -d ₆₎
The introduction rate of the taurine salt calculated by was 4.7%.

Examples 2 and 3 A sulfonic acid group-introduced polyaspartate was obtained in the same manner as in Example 1, except that the starting materials, the amount of taurine salt and the reaction temperature were changed as shown in Table 1. . Table 1 shows the results.

[0020]

Table 1 Starting materials Taurine salt Reaction temperature Introduction rate Example 2 (Resin F) Resin A (94 g) 14.2 g 140 ° C 9.8% Example 3 (Resin G) Resin C (100 g) 7.58 g 100 ° C 4.7%

Comparative Example 1 Resin C (10 g) and N, N-dimethylformamide (56 g) were charged into a 100 ml eggplant-shaped flask, and resin C was dissolved. Subsequently, after adding taurine (1.29 g) to the reaction solution, the reaction was carried out at room temperature for 24 hours. After completion of the reaction, the reaction solution was dropped into methanol (1 L) to crystallize the polymer. After the mixture was filtered, the solid was removed from methanol (50
0 ml) and dried under reduced pressure at 100 ° C. for 24 hours to obtain 10.4 g of a yellow-white solid. Next, for hydrolysis, 93% sodium hydroxide (0.23 g) and water (2 g) were charged into a 50 ml beaker to dissolve the sodium hydroxide. After cooling the beaker with ice water, the yellowish white solid (0.5 g) was added little by little, and then stirred at room temperature for 1 hour. After completion of the reaction, the reaction solution was dropped into methanol (100 ml) to crystallize the polymer.
After filtering the mixture, the solid was washed twice with methanol (50 ml) and dried under reduced pressure at 50 ° C. for 24 hours to obtain 0.54 g of a yellow-white solid. Hereinafter, this product is referred to as a resin H. Proton NMR of this resin (dimethyl sulfoxide-
The introduction rate of taurine calculated according to d ₆ ) was 0%.

Comparative Example 2 Resin C (1.0 g) and N, N-dimethylformamide (4.0 g) were charged into a 100 ml eggplant-shaped flask.
Resin C was dissolved. Subsequently, taurine (0.13 g) was added to the reaction solution, which was then attached to a rotary evaporator set at a bath temperature of 150 ° C., and heated for 3 hours. After completion of the reaction, the reaction solution was dropped into methanol (100 ml),
The polymer was crystallized. After filtering the mixture, the solid was washed twice with methanol (50 ml) and dried under reduced pressure at 100 ° C. for 24 hours to obtain 0.99 g of a yellow-white solid. Next, for hydrolysis, 93% sodium hydroxide (0.23 g) and water (2 g) were charged into a 50 ml beaker to dissolve the sodium hydroxide. After cooling the beaker with ice water, the yellowish white solid (0.5 g) was added little by little, and then stirred at room temperature for 1 hour. After completion of the reaction, the reaction solution was dropped into methanol (100 ml) to crystallize the polymer. After the mixture was filtered, the solid was removed from methanol (50 ml).
And dried under reduced pressure at 50 ° C. for 24 hours to obtain 0.50 g of a yellow-white solid. Hereinafter, this product is referred to as a resin H. The introduction ratio of taurine of this resin calculated by proton NMR (dimethyl sulfoxide-d ₆ ) was 0%. Production Examples 1 and 2, Examples 1 to 3 and Comparative Examples 1 and 2
Using the polyaspartate and the sulfonic acid group-introduced polyaspartate obtained in the above, a calcium carbonate scale inhibition test shown below was performed to evaluate the scale prevention ability.

Evaluation method Calcium chloride in demineralized water, Resin B obtained in Production Examples 1 and 2, Examples 1 to 3 and Comparative Examples 1 and 2 as scale inhibitors,
Aqueous solutions of D, E, F, G, H and sodium hydrogen carbonate were added in this order, and a small amount of a 1N aqueous sodium hydroxide solution was further added to prepare 500 ml of a test solution having a pH of 8.5. The calcium hardness of this test solution was 250 mg / L as CaCO ₃ , the M-alkalinity was 250 mg / L as CaCO ₃ , and the concentration of the scale inhibitor was:
0.5 mg / L. These test liquids were placed in a 500 ml conical beaker, sealed with a polyethylene film, and then heated at 60 ° C. in a thermostatic water bath. 0.1μ
The test solution was filtered with a filter paper of m, and the residual calcium hardness in the filtrate was measured. Table 2 shows the results.

[0024]

Table 2 Results of calcium carbonate scale inhibition test Example Resin name Inhibition rate (%) Example 1 Resin E 100.0 Example 2 Resin F 91.2 Example 3 Resin G 100.0 Production Example 1 Resin B 82.4 Production Example 2 Resin D 76.8 Comparative Example 1 Resin H 75.5 Comparative Example 2 〃 75.3

[0025]

According to the method of the present invention, polyaspartic acid having an aminosulfonic acid group introduced therein can be easily obtained, and a water treatment agent having a high scale preventing ability can be obtained by using the compound.

Continued on the front page (72) Inventor Masayuki Tomita 8-3-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Pref. Inside Tsukuba Research Laboratory, Mitsubishi Chemical Corporation (72) Inventor Takeshi Nakato 8-3-Chuo, Ami-cho, Inashiki-gun, Ibaraki Prefecture No. 1 Inside Tsukuba Research Laboratory, Mitsubishi Chemical Corporation

Claims (7)

[Claims] 1. A method for producing a modified polyaspartic acid, comprising reacting a polysuccinimide with an aminosulfonate to form an aminosulfonate, and then hydrolyzing the remaining imide ring. 2. The method for producing modified polyaspartic acid according to claim 1, wherein the aminosulfonate is an alkali metal salt. 3. The aminosulfonate according to claim 1, wherein the aminosulfonate is at least one selected from 2-aminoethylsulfonate, aminomethanesulfonate and aminobenzenesulfonate. For producing a modified polyaspartic acid. 4. The method for producing a modified polyaspartic acid according to claim 1, wherein the reaction temperature between the polysuccinimide and the aminosulfonic acid salt is 0 ° C. or more and less than 150 ° C. 5. The modified polyaspartic acid according to claim 1, wherein the polysuccinimide is a polysuccinimide produced using 0.002 to 0.3 mol of the catalyst per 1 mol of the raw material. Production method. 6. A water treatment agent comprising the modified polyaspartic acid according to claim 1. 7. The amount of aminosulfonate introduced into polysuccinimide is 0.1 mol% based on the imide unit.
The water treatment agent according to claim 6, wherein the content is at least 20 mol%.