JPH09278883A - Production of polysuccinimide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high-molecular-weight polysuccinimide by using a conventional method in which phosphoric acid is used. SOLUTION: A reaction product or mixture of aspartic acid, maleamic acid, maleic acid and ammonia is polycondensed in the presence of a phosphorous compound represented by formula I (wherein R is 3-20C (halo)alkyl or a 6-20C (halo)aryl) or formula II (wherein Ar is 6-20C (halo)aryl).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing polysuccinimide. The polysuccinimide obtained by the method of the present invention is useful as a precursor of polyaspartic acid, and these polysuccinimide and polyaspartic acid are chelating agents, scale inhibitors, detergent builders, and dispersants. It can be used as a moisturizer, an additive for fertilizers, etc.

[0002]

2. Description of the Related Art Conventionally, as a method for producing polysuccinimide, a large amount of an acid catalyst such as aspartic acid and phosphoric acid is used, and polymerization is carried out in a vacuum at a temperature of 170 to 200 ° C. (Japanese Patent Publication No. 48-20638). US Patent 5,14
2,062). By this method, high molecular weight polysuccinimide can be obtained, but removal of the residual catalyst is difficult. On the other hand, as a manufacturing method using a small amount of catalyst,
A method of uniformly mixing amino acids such as aspartic acid and an acid catalyst and polymerizing at a temperature of 110 to 300 ° C. (European Patent 644,257), and as a non-catalytic method, aspartic acid and maleamic acid Of solid phase reaction at a high temperature of 180 ° C. or higher (US Pat. No. 5,053)
No. 7,597, No. 5,219,986, and JP-A-6-206937) are known. However, the polysuccinimide obtained by these methods has problems that the molecular weight is low and the polymerization rate is slow.
In addition, in these conventional production methods, a large amount of residual monomer remains in the polysuccinimide, and therefore, there is a problem that the physical properties are deteriorated depending on the application such as a chelating agent.

[0003]

Therefore, it has been desired to develop a new catalyst capable of producing a high-molecular-weight polysuccinimide in a short time by a method capable of being industrially produced. An object of the present invention is to provide a method for efficiently producing a high molecular weight polysuccinimide.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have shown that a monomer such as aspartic acid is subjected to a polycondensation reaction in the presence of a specific phosphite compound. It was found that a high molecular weight polysuccinimide can be easily produced in a short time, and the present invention has been completed.

That is, the present invention provides a reaction product of aspartic acid, maleamic acid, maleic acid and ammonia, or a mixture thereof in the presence of a phosphite compound represented by the following general formula (1) or (2). A polysuccinimide production method is characterized by polycondensation. P (OR) ₃ (1) (In the formula, R has 3 carbon atoms which may be substituted with a halogen atom.
To an alkyl group having 20 to 20 or an aryl group having 6 to 20 carbon atoms that may be substituted with a halogen atom) HP (O) (OAr) ₂ (2) (In the formula, Ar may be substituted with a halogen atom. (Indicates an aryl group having 6 to 20 carbon atoms)

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

(Phosphite Compound) The phosphite compound that can be used in the present invention is not particularly limited as long as it is a compound represented by the following general formula (1) or (2), but P (OR) ₃ (1 ) (In the formula, R has 3 carbon atoms which may be substituted with a halogen atom.)
To an alkyl group having 20 to 20 or an aryl group having 6 to 20 carbon atoms that may be substituted with a halogen atom) HP (O) (OAr) ₂ (2) (In the formula, Ar may be substituted with a halogen atom. A preferable substituent R is a C4 to C12 alkyl group which may be substituted with a halogen atom such as a chlorine atom or a bromine atom, a halogen atom such as a chlorine atom or a bromine atom, which may be substituted with a halogen atom such as a chlorine atom or a bromine atom. Examples thereof include a phenyl group which may be substituted with an atom. Specific examples of the phosphite compound include tributyl phosphite, tripentyl phosphite, trihexyl phosphite, trialkyl phosphite trialkyl esters such as phosphite, and diaryl phosphite diphenyl ester such as diphenyl phosphite. , Triphenyl phosphite, triaryl phosphite esters such as tri (p-chlorophenyl) phosphite, i-decyldiphenyl phosphite, and the like. Of these, triphenyl phosphite or tributyl phosphite is preferable.

The amount of the phosphite compound used is 0.001 to 5 with respect to 100 parts by weight of a monomer such as aspartic acid.
It is used in an amount of 00 parts by weight, preferably 0.01 to 50 parts by weight, more preferably 0.01 to 30 parts by weight.
If the amount of the phosphorous acid compound used is less than 0.001 part by weight, the effect of improving the speed of the polycondensation reaction is small. Also,
Even if it exceeds 500 parts by weight, the reaction rate does not improve.

(Monomer) In the present invention, a reaction product obtained from ammonia and maleic acid, maleamic acid, L
-, D-, DL-aspartic acid and the like can be used without particular limitation as long as they mainly produce polysuccinimide by polycondensation. Of these, aspartic acid is particularly preferable in that a high molecular weight product is easily obtained. In addition to aspartic acid, other copolymerizable monomers may be used within a range not exceeding 50%. The copolymerizable monomer is not particularly limited,
For example, aspartate; glutamic acid and salts thereof; amino acids such as alanine, leucine and lysine;
Hydroxycarboxylic acids such as glycolic acid, lactic acid and 3-hydroxybutyric acid; 2-hydroxyethanol, maleic acid, aniline and the like having one or more functional groups capable of reacting with an amino group or a carboxylic acid group other than the above And the like.

(Molecular Weight Control Agent) In the present invention, a molecular weight control agent can be used if necessary. The control agent is not particularly limited as long as it reacts with the polymer terminal during polycondensation, but a primary or secondary amine compound is preferably used. It is considered that these amines suppress the activity of polymerization by reacting with the carboxylic acid at the polymer terminal and control the molecular weight. The acid dissociation constant (pKa) in the aqueous solution is preferably 7 or less, more preferably 6 or less. The pKa used here is related to the conjugated acid of amine, and these values are the dissociation constant of an organic compound in an aqueous solution in “Chemical Handbook Basic Edition” (edited by the Chemical Society of Japan) and “Critical Stabili”.
tyConstants Vol. 1,2,3,5 "
(AE Martell, RM Smith, Pl.
Enum Press).

As the primary or secondary amine, morpholine, hexylamine, o-aminopyridine, m-aminopyridine, p-aminopyridine, butylamine, aniline, triethylenetetramine, 1-naphthylamine,
2-naphthylamine, o-aminophenol, 4-aminobutyric acid and the like can be mentioned. Among these, amines having a pKa of 6 or less include aniline, triethylenetetramine, 1-naphthylamine, 2-naphthylamine, o-aminophenol and 4-aminobutyric acid. These amines may be used alone or in combination of two or more.

The method of adding the amine to the polymerization system is not particularly limited, but the total amount may be added at the start of the polymerization or may be added over time. The addition amount can be changed depending on the type of amine used and the molecular weight of the intended polymer. In order to obtain low molecular weight polymers, it is necessary to use a larger amount of amines. Usually, it is used in an amount of 100 mol% or less, preferably 80 mol% or less, more preferably 60 mol% or less based on the monomers.

(Reaction Conditions) The reaction conditions in the production method of the present invention are not particularly limited, but the monomer and the catalyst are polycondensed in the presence of a solvent, or in the absence thereof, they are mixed by a wet or dry method. After that, polycondensation can be performed. In addition, polycondensation (bulk polymerization) in the absence of a solvent is
Since no solvent is used, the production cost is low, but compared to the solvent method, there is a drawback that a high molecular weight cannot be obtained, but when the method of the present invention is applied, it is possible to increase the molecular weight of polysuccinimide. , Particularly preferred. The pressure during the reaction is not particularly limited and may be normal pressure, reduced pressure, or increased pressure, but is usually in the range of 10 Pa to 1 MPa.

The polycondensation in the absence of a reaction solvent (bulk polymerization) and the polycondensation in the presence of a solvent will be described below in order. a) Bulk Polymerization (Mixing method) In the method of the present invention, the dispersion state of the catalyst is not limited, but a powdery monomer is used before the polycondensation reaction.
It is preferable to thoroughly mix and the catalyst. If polycondensation is started in a state where the mixed state is insufficient, it partially melts and solidifies,
Problems such as a decrease in molecular weight and an increase in reaction time may occur.

Examples of the mixing method include a catalyst, a wet mixing method using a solvent as a diluent, and a dry mixing method using an apparatus. The mixing temperature is not particularly limited as long as it is 150 ° C. or lower at which polycondensation to polysuccinimide does not occur, but is preferably a temperature from room temperature to 120 ° C., and a mixing time is 0.01 to 600 minutes, preferably 0.01. ~
The mixing is performed for 300 minutes, more preferably for 0.01 to 50 minutes.

In the case of the wet mixing method, a solvent and a catalyst are mixed, and then each mixture is mixed with a powdery monomer. At that time, the solvent that can be used is not particularly limited, but it is preferable that the solvent has a boiling point of 150 ° C. or lower in consideration of the need to distill off after the mixing is completed, and the solvent can be uniformly mixed with the catalyst to be used. Specifically, hexane, cyclohexane and other aliphatic and alicyclic hydrocarbons, benzene, aromatic hydrocarbons such as toluene, ethyl acetate, esters such as butyl acetate, acetone,
Ketones such as methyl ethyl ketone, methanol, ethanol
Alcohol such as alcohol and propanol, and water. Water is particularly preferable in that it is by-produced in the subsequent reaction and does not require a complicated recovery step.

The above solvent is used in an amount of usually 0.1 to 30 parts by weight, preferably 0.5 to 25 parts by weight, based on 100 parts by weight of the monomer. The amount used is 0.
When it is less than 1, the effect of improving the speed of the polycondensation reaction is small. Further, if it exceeds 30, it is not preferable because it takes a long time for the distillation. When the dry mixing method is used, the catalyst is added to the monomer and then mixed using a mixing device. There is no particular limitation on the method of adding the catalyst, even if added at once,
You may add little by little.

As a mixing device that can be used, a general mixer, blender, kneader or the like is preferable, and as a concrete example of a large-scale apparatus of stirring and kneading type, a uniaxial or biaxial extruder or a high-viscosity reaction is used. Machine, SV-mixer, and conical dryer (Shinko Pantech Co., Ltd.), MZ-
Processor (Okawara Seisakusho), paddle dryer
(Nara Machinery Co., Ltd.), SC-processor and pressure kneader (Kurimoto).

(Polycondensation Reaction) In the polycondensation reaction in the method of the present invention, 100 to 4 are prepared by charging the mixture into a reactor.
Under heating at 00 ° C, preferably 150 to 350 ° C, the average residence time is 0.01 to 240 minutes, preferably 0.01 to 240 minutes.
The reaction is carried out in the solid phase for 180 minutes, more preferably 0.01 to 100 minutes while stirring or kneading.

If the reaction temperature is less than 100 ° C. and the average residence time is less than 0.01 minutes, the reaction may not be completed. Further, if the reaction is carried out at a reaction temperature of more than 400 ° C. and an average residence time of more than 240 minutes, decomposition products may be produced or the reaction efficiency may be reduced. As a reactor satisfying the above conditions, either a batch type or a continuous type may be used, and in the batch type, a normal reactor, a pro-mixer (Pacific Kiko Co., Ltd.), a Polyphase System, etc.
m (Littleford Day), SV-mixer, MZ-processor and batch type kneader. In the continuous type, single-screw and twin-screw kneaders, paddle dryers, LCRs (Lurgi), SC processors, KRC kneaders (Kurimoto), Bivolac (Sumitomo Heavy Industries) and N-SCR (Mitsubishi). (Heavy Industries) is a specific example.

The polymerization reaction is preferably carried out under an inert gas stream. There is no particular limitation as an inert gas,
Nitrogen, argon or the like can be used. b) Polycondensation Using Reaction Solvent (Reaction Solvent) The solvent that can be used in the method of the present invention is preferably aromatic hydrocarbons, halogenated hydrocarbons, ethers, and esters, and among them, the boiling point is Solvents having a temperature of 100 ° C or higher, preferably 130 ° C or higher are preferred.
These solvents can be used alone or as a mixture.

Specifically, aromatic hydrocarbons such as toluene, xylene, diethylbenzene, amylbenzene, cumene, mesitylene, and tetralin; chlorotoluene, dichlorotoluene and their isomers (mixing of two or more kinds of isomers are possible. ) Halogenated hydrocarbons such as 1,4-dichlorobutane, chlorobenzene and dichloroethyl ether; butyl ether, diisoamyl ether, aniso-
Ethers such as ethyl acetate-n-amyl acetate, isoamyl acetate, methyl isoamyl acetate, methoxybutyl acetate, cyclohexyl acetate, benzyl acetate, propionate-n-butyl, isoamyl propionate, isoamyl butyrate, butyrate-n-butyl Esters such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone,
Aprotic polar solvents such as tetramethylurea acid, dimethylsulfoxide, sulfolane, hexamethylphosphoramide and the like can be mentioned. Among these, diethylbenzene, cumene, chlorotoluene, 1,4-dichlorobutane, mesitylene, diisoamyl ether, butyrate-n-butyl, 1,3-dimethyl-2-imidazo, which have an appropriate boiling point. Lidinone and sulfolane are preferable, and cumene, chlorotoluene, mesitylene, 1,3-dimethyl-2-imidazolidinone and sulfolane are more preferable. The solvent is 1 to 5000 parts by weight, preferably 5 to 20 parts by weight with respect to 100 parts by weight of aspartic acid.
It can be used in a proportion of 00 parts by weight.

(Polycondensation Reaction) The temperature of the polycondensation reaction in the method of the present invention is 10 when the mixture is charged into a reactor.
It is in the range of 0 to 350 ° C, preferably 130 to 300 ° C. If the reaction temperature is lower than 100 ° C, the reaction does not proceed easily, which is not preferable. Further, if the temperature exceeds 350 ° C., it is economically unfavorable such that decomposition products are generated and the thermal efficiency is not good.

The reaction time is 1 minute to 100 hours, preferably 10 to 50 hours, most preferably 15 minutes to 20 hours, with stirring. Further, the substantial end point of the reaction is the time when water is no longer produced from the reaction system.

(Post-treatment) The post-treatment step can be appropriately selected depending on the intended use of the polymer. Specifically, 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. Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples.

[0025]

[Examples] The molecular weight of polysuccinimide in Examples 1 to 5 and Comparative Examples 1 to 4 was as follows: "PLgel" 5 μm MIXE-C column manufactured by Polymer Laboratory Ltd., 10 mM lithium bromide dimethyl as an eluent. It is a polystyrene conversion value obtained by a GPC chromatograph (differential refractometer) using formamide. The molecular weight of polysuccinimide in Examples 6 to 8 and Comparative Examples 5 and 6 is
Co., Ltd. “TSKgel” “GMHHR-M” column, “TSKgel” “G2000HHR” column, polystyrene conversion obtained by GPC chromatograph (differential refractometer) using dimethylformamide of 10 mM lithium bromide as an eluent It is a value. For the conversion rate and monomer residual rate, refer to "TL" manufactured by Polymer Laboratory Co., Ltd.
It was measured by liquid chromatography using two GEL 5 μm MIX ED-C ”columns and 20 mM dimethylformamide of lithium bromide as an eluent.

<Example 1> 50 g of L-aspartic acid
Was charged into a 200 mL separable flask equipped with a condenser, a thermometer, and a stirrer, and 5 g of tributyl phosphite dissolved in 20 g of acetone was added. Under a nitrogen atmosphere, the mantle heater was heated to 165 ° C., only acetone was distilled off, and then the heater was set to 235 ° C. to start the polycondensation reaction. After the generation of water was recognized in the system, stirring was continued for 3 hours to obtain pale yellow polysuccinimide. The polymerization average molecular weight of this polysuccinimide was 20,000. <Examples 2 to 5, Comparative Examples 1 to 4> The same operation as in Example 1 was carried out except that tributyl phosphite was used as the phosphoric acid or the phosphorous acid compound described in Table 1, and the results are shown in Table 1. Described.

[0027]

Table 1 Catalyst components Weight average molecular weight Conversion rate Monomer residual rate Comparative example 1 Phosphoric acid 17000 99.8% 0.2% Comparative example 2 Phosphorous acid 18000 99.7 0.3 Comparative example 3 Trimethyl phosphite 19000 60.5 39.5 Comparative example 4 Phosphorous Triethyl phosphite 19000 94.7 5.3 Example 1 tributyl phosphite 20000 99.8 0.2 Example 2 diphenyl phosphite 24000 99.8 0.2 Example 3 triphenyl phosphite 24000 99.8 0.2 Example 4 p-chlorotriphenyl phosphite 26000 99.7 0.3 Example 5 i-decyldiphenyl phosphite 22000 99.8 0.2

<Example 6> A 200 mL four-necked flask equipped with a stirrer, a water separator and a condenser, and a thermometer was charged with L-.
25 g of aspartic acid, 5 g of triphenyl phosphite, 56 g of mesitylene as a reaction solvent and 24 g of sulfolane were added. The oil bath was set at 190 ° C., and the polycondensation reaction was started under a nitrogen stream. 4 hours after the reaction system started destillation,
The mixture was stirred while removing water from the system. After completion of the reaction, the product was washed with methanol and water and dried under reduced pressure to obtain 18.0 g of polysuccinimide. The weight average molecular weight of this polymer was 75,000.

Example 7 Sulfolane 8 as a reaction solvent
The same operation as in Example 6 was carried out except that 0 g was used to obtain 18.0 g of pale yellow polysuccinimide. The polymerization average molecular weight of this polysuccinimide is 30,000.
It was 0. <Example 8> The same operation as in Example 6 was carried out except that diphenyl phosphite was used instead of triphenyl phosphite to obtain 18.2 g of pale yellow polysuccinimide. The polymerization average molecular weight of this polysuccinimide is 6
It was 5,000.

Comparative Example 5 The same operation as in Example 6 was carried out except that phosphoric acid was used instead of triphenyl phosphite to obtain 18.5 g of pale yellow polysuccinimide. The polymerization average molecular weight of this polysuccinimide is 6
It was 0000. <Comparative Example 6> The same operation as in Example 7 was carried out except that phosphoric acid was used instead of triphenyl phosphite to obtain 18.5 g of pale yellow polysuccinimide. The polymerization average molecular weight of this polysuccinimide was 25,000.

[0031]

EFFECT OF THE INVENTION The method for producing polysuccinimide of the present invention has a low residual monomer ratio as compared with the conventional production method using phosphoric acid and phosphorous acid by using a specific phosphite, In addition, high molecular weight polysuccinimide is obtained. Therefore, in the case of obtaining polysuccinimide of the same molecular weight, in addition to the industrially advantageous production method, such as shortening the polymerization time, it is possible to reduce the amount of use of the catalyst amount, thickener and It is particularly preferable in the case where the effect is large by increasing the molecular weight of the crosslinked base polymer or the like or when a high dispersive power is required such as a builder of a detergent. Further, the quality of the product is less likely to deteriorate without purification, which is industrially advantageous.

Claims (4)

[Claims] 1. Polycondensation of aspartic acid, maleamic acid, a reaction product of maleic acid and ammonia, or a mixture thereof in the presence of a phosphorous acid compound represented by the following general formula (1) or (2): A method for producing polysuccinimide, which comprises: P (OR) ₃ (1) (In the formula, R has 3 carbon atoms which may be substituted with a halogen atom.
To an alkyl group having 20 to 20 or an aryl group having 6 to 20 carbon atoms that may be substituted with a halogen atom) HP (O) (OAr) ₂ (2) (In the formula, Ar may be substituted with a halogen atom. (Indicates an aryl group having 6 to 20 carbon atoms) 2. Aspartic acid, maleamic acid, a reaction product of maleic acid and ammonia, or a mixture thereof 1.
0.001 to 50 parts by weight of the phosphite compound with respect to 00 parts by weight
The method for producing polysuccinimide according to claim 1, wherein the polysuccinimide is used in an amount of 0 part by weight. 3. The method for producing polysuccinimide according to claim 1 or 2, wherein the polycondensation method is bulk polymerization. 4. The method for producing polysuccinimide according to claim 1, wherein the phosphite compound is triphenyl phosphite or tributyl phosphite.