JP2000128943A - Production of glyoxylic salt-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a glyoxylic salt-based polymer capable of readily removing a solvent without any remaining solvent. SOLUTION: This method for producing a glyoxylic salt-based polymer comprises using a carboxylic acid ester as a solvent in the method for producing the glyoxylic salt-based polymer by polymerizing a monomer component containing a glyoxylic acid ester in the presence of the solvent, providing a glyoxylic acid-based polymer and then saponifying the resultant polymer. The carboxylic acid ester more preferably has an alkoxycarbonyl of the same structure as that of the alkoxycarbonyl possessed by the glyoxylic acid ester. An acetic acid ester is more preferred as the carboxylic acid ester and methyl acetate is especially preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to various kinds of builder, chelating agent, complexing agent, sequestering agent and the like for detergents, or as raw materials for biodegradable films and synthetic resin products. The present invention relates to a method for producing a glyoxylate-based polymer suitably used for applications.

[0002]

2. Description of the Related Art Glyoxylate polymers have a large number of carboxyl groups in the molecule and are therefore excellent in the action of capturing calcium ions and magnesium ions present in water (chelating action, dispersing action). Since it is free of phosphorus that causes environmental pollution such as eutrophication of rivers and the like, it has been conventionally suitably used as a detergent builder.

[0003] As a method for producing a glyoxylate polymer, for example, Japanese Patent Application Laid-Open Nos.
No. 2,503,316 (corresponding U.S. Pat. No. 4,600,7)
No. 50), a glyoxylic acid ester is polymerized using a solvent such as an alkyl nitrile, a halogenated hydrocarbon, dimethyl sulfoxide, or acetone to obtain a glyoxylic acid-based polymer, which is then saponified (hydrolyzed). Decomposition) to give a glyoxylate polymer. In addition, in the above publication, from the viewpoint of easy removal,
It is described that methylene chloride is particularly preferred as the solvent.

[0004]

However, in the above-mentioned conventional production method, even if an operation such as heating is performed prior to the saponification, the solvent cannot be completely removed. The solvent is slightly contained in the system polymer. That is, in the glyoxylate-based polymer obtained by the above-mentioned conventional production method, a small amount of a solvent such as an alkyl nitrile, a halogenated hydrocarbon, dimethyl sulfoxide, or acetone remains. Glyoxylate polymers in which these solvents, especially halogenated hydrocarbons having relatively high toxicity remain, have problems in terms of safety.
Further, when the glyoxylate-based polymer is used, for example, as a builder for a detergent, it causes problems such as environmental pollution. When the alcohol produced by saponification of the glyoxylic acid polymer is reused, the alcohol contained in the alcohol as an impurity must be separated to purify the alcohol.

Accordingly, there is a need for a method capable of completely removing the solvent from the glyoxylate-based polymer, that is, a method for producing a glyoxylate-based polymer in which the solvent can be easily removed and no solvent remains. ing.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a method for producing a glyoxylate-based polymer from which a solvent can be easily removed and in which no solvent remains. It is in.

[0007]

Means for Solving the Problems The inventors of the present application have conducted intensive studies on a method for producing a glyoxylate polymer.
As a result, a method for producing a glyoxylate-based polymer by saponifying the polymer after obtaining a glyoxylate-based polymer by polymerizing a monomer component containing a glyoxylate in the presence of a solvent, The present inventors have found that by using a specific compound as the solvent, the solvent can be completely removed from the obtained glyoxylate-based polymer, thereby completing the present invention.

That is, in order to solve the above-mentioned problems, the method for producing a glyoxylate polymer according to the first aspect of the present invention comprises polymerizing a monomer component containing a glyoxylate in the presence of a solvent. In a method for producing a glyoxylate-based polymer by obtaining a glyoxylic acid-based polymer and then saponifying the polymer, a carboxylic acid ester is used as the solvent.

According to the first aspect of the present invention, when the glyoxylic acid-based polymer is saponified, the carboxylic acid ester as a solvent is also saponified and converted into the corresponding carboxylate and alcohol. Therefore, no solvent remains in the glyoxylate polymer. Further, since it is not necessary to completely remove the solvent prior to performing the saponification, the cost relating to the removal is not required, and if necessary,
The step of removing the solvent can be omitted. The alcohol can be easily removed by performing an operation such as heating. Also, even if alcohol slightly remains in the glyoxylate polymer,
Alcohols (as well as carboxylate salts) are much less toxic than conventionally used solvents such as halogenated hydrocarbons, and therefore have no safety problems, and are not subject to environmental pollution. No problem. This makes it possible to provide a method for producing a glyoxylate polymer in which the solvent is easily removed and the solvent does not remain.

According to a second aspect of the present invention, there is provided a method for producing a glyoxylate-based polymer according to the first aspect of the present invention, wherein the carboxylic acid ester has glyoxylate. It is characterized by having an alkoxycarbonyl having the same structure as the alkoxycarbonyl.

[0011] According to the method of claim 2, an alcohol produced by saponification of a glyoxylic acid-based polymer;
The alcohol and the alcohol produced by the saponification of the solvent become the same compound. Therefore, when recycling the alcohol generated by the saponification of the glyoxylic acid polymer,
There is no need to purify the alcohol. Therefore, recovery and reuse of the alcohol are facilitated.

According to a third aspect of the present invention, there is provided a method for producing a glyoxylate-based polymer according to the first or second aspect, wherein the carboxylic acid ester is an acetate ester. It is characterized by:

According to the method of the third aspect, the carboxylate produced by saponification of the solvent is an acetate.
A glyoxylate-based polymer which is more excellent in safety and the like can be produced.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a glyoxylate polymer according to the present invention comprises the steps of: polymerizing a monomer component containing a glyoxylate in the presence of a solvent to obtain a glyoxylate polymer; In the method for producing a glyoxylate-based polymer by saponifying the polymer, as the solvent,
This is a method using a carboxylic acid ester. The above glyoxylic acid-based polymer has the general formula (1)

[0015]

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(Wherein R ₁ represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, or an aromatic hydrocarbon group).

First, a method for producing a glyoxylic acid-based polymer will be described. The glyoxylic acid-based polymer,
General formula (2) OHC-CO-OR ₁ (2) (wherein, R ₁ is an alkyl group having 1 to 18 carbon atoms, 2 carbon atoms)
To 18 alkenyl groups or aromatic hydrocarbon groups), and can be easily obtained by polymerization in the presence of a polymerization initiator, a polymerization catalyst, and a solvent. be able to.

The above glyoxylate is represented by the formula:
It is more preferable that the substituent represented by R ₁ be an alkyl group having 1 to 4 carbon atoms because steric hindrance during polymerization can be reduced. Specific examples of the glyoxylate include methyl glyoxylate, ethyl glyoxylate, n-propyl glyoxylate, isopropyl glyoxylate, n-butyl glyoxylate, isobutyl glyoxylate, sec-butyl glyoxylate,
T-butyl glyoxylate. One of these glyoxylates may be used alone, or two or more thereof may be used in combination. Of the above glyoxylates, methyl glyoxylate and ethyl glyoxylate are more preferred, and methyl glyoxylate is still more preferred.

The method for producing glyoxylate is not particularly limited. Glyoxylic acid ester can be easily produced, for example, by reacting a hydrate of glyoxylic acid with an alcohol, and dehydrating a hemiacetal ester of glyoxylic acid using phosphorus pentoxide or sulfuric acid. it can.

The polymerization of the glyoxylic acid ester may proceed gradually even during storage (during storage) depending on the storage conditions. Therefore, it is desirable to purify the glyoxylate by removing an impurity such as a polymer by performing an operation such as distillation prior to use. That is, it is desirable that the glyoxylate used for the polymerization has as high a purity as possible. Further, it is preferable that the purified glyoxylate is promptly subjected to polymerization.

The monomer component may contain, in addition to the glyoxylate, a monomer (comonomer) copolymerizable with the glyoxylate, if necessary. Specific examples of the monomer include epoxides such as ethylene oxide, propylene oxide and epihalohydrin epoxy succinate; and aldehydes having 1 to 20 carbon atoms such as formaldehyde and acetaldehyde, but are not particularly limited. Not something. One of these monomers may be used, if necessary, or two or more of them may be used. Among the monomers exemplified above, compounds having 1 to 4 carbon atoms are more preferable. It is desirable that the above monomer is as pure as possible. Therefore,
In the present invention, “glyoxylic acid-based polymer” refers to a homopolymer or copolymer of glyoxylic acid ester.

When the monomer component contains the above-mentioned monomer, the content of the monomer is not particularly limited, but may be 5 mol or less per 1 mol of glyoxylate. More preferably, it is even more preferably 1 mol or less. When the monomer content exceeds 5 mol,
In some cases, a glyoxylate-based polymer suitable for the various uses cannot be obtained. The glyoxylic acid-based polymer according to the present invention is particularly preferably a homopolymer of glyoxylic acid ester.

Specific examples of the polymerization initiator include water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and dodecyl alcohol (hydroxyl polymerization initiator); alkyl glycolates; polyalkylene glycols and polyalkylenes. Glycol monoalkyl ether; dialkyl alkyl tartronate; and the like, but are not particularly limited. These polymerization initiators may be used alone,
Further, two or more kinds may be used in combination. Of the above-mentioned polymerization initiators, methyl alcohol is more preferred. The amount of the polymerization initiator used may be adjusted according to the desired molecular weight of the glyoxylic acid-based polymer and the like, and is not particularly limited.

As the polymerization catalyst, a basic catalyst is suitable. That is, it is more preferable that the above monomer component is anionically polymerized. Examples of the basic catalyst include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal alkoxides, amines, pyridine,
Examples include 2-hydroxypyridine / H ₂ O complex, methylmalonic acid monoester / sodium salt, but are not particularly limited. One of these basic catalysts may be used alone, or two or more thereof may be used in combination. The amount of the polymerization catalyst used may be adjusted according to the desired molecular weight of the glyoxylic acid-based polymer and the like, and is not particularly limited. As a polymerization catalyst, for example, boron trifluoride etherate or an acidic catalyst such as boron trifluoride, phosphorus pentafluoride, or a strong Lewis acid such as stannous chloride is used to convert the monomer component into a cation. It can also be polymerized.

In the production method according to the present invention, a carboxylic acid ester is used as a solvent for polymerizing the monomer component. The carboxylic acid ester can be prepared by dissolving the monomer components and glyoxylic acid-based polymer, and may be a compound that does not inhibit polymerization, is not particularly limited, general formula (3) R ₂ -CO —OR ₃ (3) (wherein, R ₂ represents an alkyl group having 1 to 4 carbon atoms or an aromatic hydrocarbon group, R ₃ represents an alkyl group having 1 to 18 carbon atoms, and 2 to 18 carbon atoms) Represents an alkenyl group or an aromatic hydrocarbon group). As the carboxylic acid ester, specifically,
For example, acetate esters such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; propionate esters such as methyl propionate; Of the carboxylic acid esters exemplified above, acetic acid esters are particularly preferred.

In the carboxylic acid ester represented by the general formula (3), the substituent represented by R ₃ is the same as the substituent represented by R ₁ in the general formula (2). Acid esters, that is, carboxylic acid esters having an alkoxycarbonyl having the same structure as the alkoxycarbonyl of the glyoxylic acid ester are more preferred. Therefore, for example, when the glyoxylate is methyl glyoxylate, the carboxylate is preferably a methyl ester such as methyl acetate or methyl propionate.

One of these carboxylic acid esters (hereinafter sometimes referred to as a solvent for the sake of convenience) may be used alone or in combination of two or more. The amount of the solvent used may be adjusted according to the viscosity of the reaction solution, the desired molecular weight of the glyoxylic acid-based polymer, the ease of a post-treatment step such as solvent removal, the volumetric efficiency of the reactor, and the like.
There is no particular limitation.

As the polymerization method, specifically, for example,
A method in which a monomer component is previously charged together with a polymerization initiator, a polymerization catalyst, and a solvent in a reactor, and then polymerized; after the polymerization initiator, a polymerization catalyst, and a solvent are charged in the reactor, the reactor A method of polymerizing while successively adding (for example, dropping) a monomer component to the mixture, but the method is not particularly limited.

The polymerization conditions such as the polymerization temperature and the polymerization time are not particularly limited, but since the polymerization is an exothermic reaction, it is more preferable to control the polymerization temperature in the range of 0 ° C. to 50 ° C. . In the final stage of the polymerization, it is more preferable to control the polymerization temperature within the range of 0 ° C to 30 ° C. The polymerization time may be appropriately adjusted according to the polymerization temperature and the like. Since the glyoxylate easily reacts with oxygen or water, the polymerization is desirably performed in the absence of oxygen or water, that is, desirably in an atmosphere of an inert gas such as nitrogen gas. Further, it is desirable that all steps related to the production of the glyoxylic acid-based polymer be performed in an atmosphere of an inert gas. The polymerization may be carried out under normal pressure (atmospheric pressure), but may be carried out under reduced pressure or under increased pressure.

By performing the above polymerization, a glyoxylic acid-based polymer is obtained in the form of a solution dissolved in a solvent. The molecular weight of the glyoxylic acid-based polymer is not particularly limited, but if it is extremely large, the solubility or dissolution rate of the glyoxylate-based polymer in water is a desired level suitable as, for example, a detergent builder. The value may not be reached. For this reason, in the glyoxylic acid-based polymer, the degree of polymerization of the glyoxylic acid ester is more preferably in the range of 5 to 1,000, and still more preferably in the range of 15 to 300.

By the way, the glyoxylic acid-based polymer obtained by polymerizing glyoxylic acid-based monomers such as glyoxylic acid ester has an unstable terminal at the end because the main chain has an acetal structure. Therefore, in order to isolate a glyoxylic acid-based polymer, for example, when a reaction solution containing the polymer is heated to remove a solvent or the like, the main chain is cleaved from the terminal portion, and the polymer is decomposed (depolymerized). )Resulting in. That is, the glyoxylic acid-based polymer cannot be stably isolated and purified at a high yield. Therefore, in order to isolate the glyoxylic acid-based polymer, it is necessary to stabilize the terminal portion of the glyoxylic acid-based polymer.

Next, a method for stabilizing the glyoxylic acid polymer will be described. When the glyoxylic acid-based polymer is not isolated, it may not be necessary to stabilize the terminal portion of the glyoxylic acid-based polymer.

In the above stabilization method, after reacting a glyoxylic acid-based polymer with a compound to be a terminal group of the polymer (hereinafter referred to as a terminal stabilizing compound) in the presence of an acidic catalyst, The basic compound A is added to the reaction system. That is, in the stabilization method, a terminal stabilizing compound is added to a solution of the glyoxylic acid-based polymer obtained by the above production method, and then the addition of the terminal stabilizing compound is performed in the presence of an acidic catalyst. After that, the basic compound A is added to the reaction solution (reaction system) within a predetermined range.

Specific examples of the terminal stabilizing compound include alkyl vinyl ethers such as ethyl vinyl ether, propyl vinyl ether and butyl vinyl ether; substituted olefins such as propylene, butylene and methyl acrylate; ethylene oxide, propylene oxide, and Epoxides such as chlorohydrin; alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol; alkyl halides such as methyl iodide, isopropyl chloride and t-butyl chloride; allyl halides such as allyl chloride; benzyl chloride and benzyl bromide Such as benzyl halide; acetaldehyde such as acetaldehyde dimethyl acetal; alkyl sulfate such as dimethyl sulfate and diethyl sulfate; and the like, but are not particularly limited.
One of these terminal stabilizing compounds may be used alone, or two or more thereof may be used in combination.

The amount of the terminal stabilizing compound to be used for the glyoxylic acid-based polymer may be determined according to the type and combination of the two, the molecular weight of the glyoxylic acid-based polymer, and the like.
Although it is not particularly limited, the molar ratio is more preferably in the range of 1.1 to 10 with respect to the terminal portion of the glyoxylic acid-based polymer. When the molar ratio of the terminal stabilizing compound is smaller than 1.1, the glyoxylic acid-based polymer may not be sufficiently stabilized. On the other hand, when the molar ratio is larger than 10, a large amount of unreacted terminal stabilizing compound remains, so that side reactions other than the addition reaction are likely to occur.

Examples of the acidic catalyst include, for example, hydrogen halides such as hydrochloric acid, protic acids such as hydrobromic acid, hydroiodic acid, trifluoroacetic acid and phosphoric acid; metals such as aluminum chloride and the like. Lewis acids such as halides, organoaluminum compounds such as alkylaluminum halides and trialkylaluminums; and the like, but are not particularly limited thereto. One of these acidic catalysts may be used alone, or two or more thereof may be used in combination. Alternatively, when the polymerization catalyst used in producing the glyoxylic acid-based polymer is an acidic catalyst, the polymerization catalyst can be used (diverted) as the acidic catalyst.
The acidic catalyst can be used for the reaction in a state of being dissolved in an aliphatic hydrocarbon such as hexane, if necessary.

The amount of the acidic catalyst used for the glyoxylic acid polymer or the terminal stabilizing compound depends on the kind of the acidic catalyst, the combination with the glyoxylic acid polymer or the terminal stabilizing compound, and the molecular weight of the glyoxylic acid polymer. It should just be set according to, and it is not particularly limited. However,
The solution of the glyoxylic acid-based polymer contains a basic substance B such as a polymerization catalyst used at the time of polymerization. Therefore, it is necessary to use the acidic catalyst in an amount larger than that required for neutralizing the basic substance B.

In the addition reaction of the terminal stabilizing compound with the glyoxylic acid-based polymer, if necessary, more specifically, to reduce the viscosity of the reaction solution, that is, to dilute the reaction solution Further, a solvent may be further added to the reaction solution. Specific examples of the solvent for dilution include the carboxylic esters described above. However, it is desirable to select the same compound as the solvent used at the time of the polymerization, as the solvent for dilution, so that the recovery, purification, reuse and the like of the solvent can be performed easily and inexpensively.

As the reaction method, specifically, for example,
A method in which a terminal stabilizing compound and an acidic catalyst are added all at once to a solution of a glyoxylic acid-based polymer and then reacted;
A method in which an acidic catalyst is added to a solution of a glyoxylic acid-based polymer and then a reaction is performed while sequentially adding (for example, dropping) a terminal stabilizing compound; and the like are not particularly limited. That is, the order and method of mixing the glyoxylic acid-based polymer solution, the terminal stabilizing compound, and the acidic catalyst are not particularly limited.

The reaction conditions for the addition reaction of the terminal stabilizing compound to the glyoxylic acid-based polymer are not particularly limited, but the reaction temperature is more preferably in the range of 0 ° C. to 50 ° C. The temperature is more preferably in the range of 15 ° C to 40 ° C, and particularly preferably in the range of 25 ° C to 35 ° C. The reaction time depends on the reaction temperature and the like.
What is necessary is just to adjust suitably. The reaction is desirably performed in the absence of oxygen or water, that is, in an atmosphere of an inert gas such as nitrogen gas. Further, it is desirable that all steps related to stabilization of the glyoxylic acid-based polymer be performed in an atmosphere of an inert gas. The reaction may be carried out under normal pressure (atmospheric pressure), but may be carried out under reduced pressure or under increased pressure.

By performing the above addition reaction, the terminal stabilizing compound is introduced as a terminal group into the glyoxylic acid-based polymer, and the polymer is stabilized.

As the basic compound A, for example,
Examples thereof include, but are not particularly limited to, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal alkoxides, alkali metal carbonates, and amines. As the amine, specifically, for example, ethylamine, n-propylamine, isopropylamine,
aliphatic amines such as n-butylamine, sec-butylamine, t-butylamine, dodecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, triethylamine, N, N-dimethyldodecylamine, cyclohexylamine and dicyclohexylamine; allylamine; Aromatic amines such as benzylamine and aniline; pyridine; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; and the like, but are not particularly limited. These basic compounds A may be used alone or in combination of two or more.

Of the basic compounds A exemplified above, amines are more preferred. Then, among the above exemplified amines, amines having a boiling point of 80 ° C. or higher are more preferable, amines having a boiling point of 100 ° C. or higher are more preferable, and amines having a boiling point of 120 ° C. or higher are particularly preferable. Further, alkanolamines are more preferable, and tertiary amines are particularly preferable in terms of less coloring, and triethanolamine is most preferable since it is more safe and odorless.

The amount of the basic compound A to be used with respect to the acidic catalyst may be determined according to the type and combination of the two, and is not particularly limited. % To 200 mol%, more preferably 50 mol% to 150 mol%, is more preferably added to the reaction system, that is, the reaction solution (addition reaction mixture). Thereby, the acidic catalyst contained in the reaction solution can be deactivated.
Since the acidic catalyst is consumed to some extent during the addition reaction,
In some cases, the acidic catalyst can be deactivated without adding an equimolar amount of the basic compound A to the initially added acidic catalyst.

As a method for isolating and purifying the stabilized glyoxylic acid-based polymer, specifically, for example, the reaction solution containing the polymer may be heated to remove the solvent and the like. It is not limited. According to the above stabilization method, the acidic catalyst is deactivated by reacting with the basic compound A, so that the main chain of the polymer can be prevented from being cut by the action of the acidic catalyst. Therefore, in order to isolate a glyoxylic acid-based polymer, for example, even if an operation such as heating a reaction solution containing the polymer to remove a solvent or the like is performed, decomposition of the polymer by the action of an acidic catalyst ( Depolymerization) can be suppressed. Therefore, by employing the above stabilization method, the glyoxylic acid-based polymer can be stably isolated and purified at a high yield. The glyoxylic acid-based polymer is suitably used, for example, as a raw material of a film or a synthetic resin product. The isolated and purified glyoxylic acid-based polymer contains a small amount of a solvent. The removed and recovered solvent can be reused after performing processing such as purification as necessary.

Next, a method for producing a glyoxylate-based polymer by saponifying (hydrolyzing) the glyoxylic acid-based polymer will be described. The glyoxylic acid-based polymer stabilized by the above method is a metal hydroxide that is a strong base and has water solubility, specifically, such as an alkali metal hydroxide or an alkaline earth metal hydroxide, Saponification (hydrolysis) can be performed using a hydroxide of a monovalent metal, a divalent metal or a trivalent metal. By saponifying a glyoxylic acid-based polymer, for example, water solubility can be imparted to the polymer (to be a water-soluble polymer).

Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like. Examples of the alkaline earth metal hydroxide include magnesium hydroxide and calcium hydroxide. One of these metal hydroxides may be used alone, or two or more thereof may be used in combination. When the glyoxylate-based polymer is used, for example, as a detergent builder among the metal hydroxides exemplified above, sodium hydroxide and potassium hydroxide are more preferred, and sodium hydroxide is particularly preferred. The amount of the metal hydroxide used relative to the glyoxylic acid-based polymer is desirably an amount that is about 5% to 50% excess than the theoretical amount.

The reaction method of the saponification is not particularly limited, but an aqueous solution of a metal hydroxide is added to the glyoxylic acid-based polymer stabilized by the above method at once, or A method in which saponification is performed by sequential addition (for example, dropping) is preferable. When saponifying,
If necessary, water may be added to the glyoxylic acid-based polymer in advance. The concentration of the aqueous solution and the amount of water to be added are not particularly limited. Also, if necessary, without isolating the glyoxylic acid polymer,
Saponification can also be performed in the state of a reaction solution (addition reaction mixture).

The reaction conditions for the saponification are not particularly limited, but the reaction temperature is more preferably in the range of 35 ° C. to 75 ° C., and more preferably in the range of 45 ° C. to 65 ° C. Is more preferred. The reaction time may be appropriately adjusted according to the reaction temperature and the like. The saponification may be performed under normal pressure (atmospheric pressure), but may be performed under reduced pressure or under increased pressure.

By the above-mentioned saponification (hydrolysis), a metal salt of a glyoxylic acid-based polymer, that is, a glyoxylate-based polymer is obtained in the form of a solution, slurry, gel, or the like. It is desirable that the pH of the reaction solution after the saponification is maintained at a value larger than 9.5, more preferably a value larger than 10.0.

In the production method according to the present invention, when the glyoxylic acid-based polymer is saponified, the carboxylic acid ester, which is a solvent slightly contained in the polymer, is also saponified to form the corresponding carboxylic acid. Converted to salt and alcohol. Therefore, no solvent remains in the glyoxylate polymer. Further, prior to performing the saponification, that is, when isolating the glyoxylic acid-based polymer, it is not necessary to completely remove the solvent, so that the cost related to the removal is not required, and if necessary, The step of removing the solvent can be omitted. The alcohol can be easily removed by performing an operation such as heating. Even if a small amount of alcohol remains in the glyoxylate-based polymer, the alcohol (and carboxylate) is far less toxic than conventional solvents such as halogenated hydrocarbons. Since it is low, there is no problem in terms of safety, and there is no problem such as environmental pollution. This makes it possible to provide a method for producing a glyoxylate polymer in which the solvent is easily removed and the solvent does not remain.

When a carboxylic acid ester having an alkoxycarbonyl having the same structure as that of the glyoxylic acid ester is used as the solvent, the alcohol formed by saponification of the glyoxylic acid-based polymer and the saponification of the solvent are used. And the alcohol produced by the chemical conversion becomes the same compound. Therefore, when the alcohol produced by saponification of the glyoxylic acid-based polymer is reused, for example, as a raw material for producing glyoxylic acid ester, it is not necessary to purify the alcohol. Therefore, recovery and reuse of the alcohol are facilitated.
Furthermore, when an acetic ester is used as a solvent,
Since the carboxylate generated by the saponification of the solvent becomes an acetate, a glyoxylate-based polymer which is more excellent in safety and the like can be produced.

The water and the alcohol by-produced by the saponification (more preferably, an alcohol having 1 to 4 carbon atoms) may be collected together with the saponification or after the saponification. When alcohol and the like are recovered together with saponification, the above reaction conditions may be set to a reaction temperature and pressure at which the alcohol and the like volatilize (evaporate).

As a method for isolating and purifying the glyoxylate-based polymer, specifically, for example, a reaction solution containing the polymer may be heated to remove the above-mentioned alcohol and the like. It is not something to be done. As a result, the glyoxylate-based polymer can be stably isolated and purified in a dry solid state or a wet cake state with a high yield. The glyoxylate-based polymer is suitably used, for example, as a builder for detergents, a chelating agent, a complexing agent, a sequestering agent, and the like.

The carboxylate formed by saponification of the solvent has no volatility and has almost no toxicity.
Even if it is contained in the glyoxylate-based polymer, there is no problem in terms of safety and no problem such as environmental pollution is caused. The carboxylate may be removed from the glyoxylate-based polymer depending on the use and the like. The method for removing the carboxylate is not particularly limited.

In the production method according to the present invention,
When the glyoxylic acid-based polymer is not isolated, more specifically, when the solvent is not removed and recovered prior to the saponification, the basic compound A is added to the reaction solution (addition reaction mixture). And a step of saponifying (hydrolyzing) the glyoxylic acid-based polymer to obtain a glyoxylate-based polymer. That is, by using a metal hydroxide as the basic compound A, deactivation of an acidic catalyst and saponification of a glyoxylic acid-based polymer and a carboxylic acid ester can be carried out in one step. . The amount of metal hydroxide (basic compound A) used in this case is
The amount may be set in consideration of the total amount of the glyoxylate and the solvent charged during the polymerization and the amount of the acidic catalyst added during the addition reaction.

[0057]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 A glass reactor equipped with a thermometer, a dropping funnel, a stirrer, a nitrogen gas inlet tube, and a reflux condenser was charged with 10 ml of methyl acetate as a solvent (carboxylate), and polymerization was started. 0.25 ml of methyl alcohol as an agent and pyridine 1 as a polymerization catalyst
0 μl was charged. On the other hand, crude methyl glyoxylate as a glyoxylate was purified by simple distillation. Then, 60 g of purified methyl glyoxylate (monomer component) was charged into the dropping funnel.

Then, under a nitrogen gas atmosphere, while stirring the contents of the reactor, methyl glyoxylate in the dropping funnel was added dropwise over 30 minutes to carry out polymerization. During the dropping period, by appropriately cooling the reactor, the temperature of the reaction solution (polymerization temperature), which is the content, is reduced to 4
It was controlled at 0 ° C. or lower. After completion of the dropwise addition, the obtained reaction solution was
Cooled to 5 ° C. Thus, a solution (reaction mixture) of poly (methyl glyoxylate) as a glyoxylic acid-based polymer was obtained.

Next, 0.1 g of boron trifluoride etherate as an acidic catalyst was added to the above reaction solution,
Stir for a minute to completely dissolve. On the other hand,
3.0 g of ethylene oxide was charged as a terminal stabilizing compound.

Then, the addition reaction was carried out by dropping ethylene oxide in the dropping funnel over 30 minutes while stirring the reaction solution in the reactor under a nitrogen gas atmosphere. During the dropping period, by appropriately cooling the reactor, the temperature (reaction temperature) of the reaction solution, which is the content, is reduced to 3
It was controlled at about 0 ° C. After completion of the dropwise addition, the reaction solution is heated to about 30 ° C.
And further stirred for 90 minutes. Thus, a solution (addition reaction mixture) of poly (methyl glyoxylate) into which ethylene oxide was introduced as a terminal group was obtained.

Subsequently, a 48% by weight aqueous solution of sodium hydroxide (metal hydroxide) was added to the solution, and the mixture was stirred to saponify poly (methyl glyoxylate) and methyl acetate. The amount of the sodium hydroxide used was set such that the molar ratio to the total amount of methyl glyoxylate and methyl acetate was 1.2, that is, 1.2 times the molar amount of the total amount. . Thus, an aqueous solution of poly (sodium glyoxylate) as a glyoxylate polymer according to the present invention was obtained.

From the obtained aqueous solution of poly (sodium glyoxylate), the pressure was reduced to 300 using an evaporator.
Under conditions of mmHg and a temperature of 50 ° C., volatiles containing methyl alcohol generated by saponification were distilled off over 30 minutes. Then, the distillate was analyzed using gas chromatography (GC). As a result, the distillate did not contain methyl acetate. That is, methyl acetate did not remain in the aqueous solution of poly (sodium glyoxylate).

Example 2 The same reaction and operation as in Example 1 were carried out except that 2.5 g of polyethylene glycol monomethyl ether (molecular weight: 400) was used as a polymerization initiator in place of methyl alcohol, and Aqueous solution of sodium glyoxylate). As a result of analysis in the same manner as in Example 1, no methyl acetate remained in the aqueous solution.

Example 3 Instead of methyl alcohol, polyethylene glycol monomethyl ether (molecular weight 4
400) An aqueous solution of poly (sodium glyoxylate) was obtained by performing the same reaction and operation as in Example 1 except that 25 g of methyl acetate was used and the amount of methyl acetate used was changed to 14 ml. As a result of analysis in the same manner as in Example 1, no methyl acetate remained in the aqueous solution.

Example 4 Instead of methyl alcohol, polyethylene glycol (molecular weight 2) was used as a polymerization initiator.
000) except that 6.0 g was used, to obtain an aqueous solution of poly (sodium glyoxylate) in the same manner as in Example 1. As a result of analysis in the same manner as in Example 1, no methyl acetate remained in the aqueous solution.

Comparative Example 1 A poly (sodium glyoxylate) for comparison was prepared in the same manner as in Example 1 except that 10 ml of a conventional solvent, methylene chloride, was used instead of methyl acetate. Was obtained. As a result of analysis in the same manner as in Example 1, the distillate contained methylene chloride. That is, an aqueous solution of poly (sodium glyoxylate) for comparison contains methylene chloride of 460 p.
pm.

[Comparative Example 2] The same reaction and operation as in Example 1 were carried out except that 10 ml of acetone, a conventional solvent, was used instead of methyl acetate, to prepare a poly (sodium glyoxylate) for comparison. An aqueous solution was obtained. As a result of analysis in the same manner as in Example 1, the distillate contained acetone. That is, in the comparative aqueous solution of poly (sodium glyoxylate), acetone remained at a rate of 20,000 ppm.

[0069]

According to the method for producing a glyoxylate polymer according to the first aspect of the present invention, as described above, a monomer component containing a glyoxylate is polymerized in the presence of a solvent to form a glyoxylate polymer. After obtaining a polymer, in a method of producing a glyoxylate-based polymer by saponifying the polymer,
In this method, a carboxylic acid ester is used as the solvent.

Therefore, the carboxylic acid ester as a solvent is also saponified and converted into the corresponding carboxylate and alcohol, so that the solvent does not remain in the glyoxylate-based polymer. Thereby, there is an effect that a method for producing a glyoxylate-based polymer in which the solvent can be easily removed and the solvent does not remain can be provided.

The method for producing a glyoxylate polymer according to claim 2 of the present invention is, as described above, a method in which the carboxylate has an alkoxycarbonyl having the same structure as the alkoxycarbonyl of the glyoxylate. is there.

Therefore, the alcohol produced by the saponification of the glyoxylic acid-based polymer and the alcohol produced by the saponification of the solvent become the same compound. Therefore, when the alcohol is reused, it is necessary to purify the alcohol. There is no. This has the effect of facilitating the recovery and reuse of the alcohol.

The method for producing a glyoxylate polymer according to the third aspect of the present invention is a method in which the carboxylic acid ester is an acetate ester as described above.

As a result, the carboxylate produced by the saponification of the solvent becomes an acetate, so that it is possible to produce a glyoxylate-based polymer which is more excellent in safety and the like.

Continued on the front page F term (reference) 4J032 AA12 AB02 AB04 AC02 AC32 AC34 AD00 AD04 AD07 AD21 AD23 AD37 AD38 AD41 AD50 AD51 AD52 AE01 AE03 AF00 AF03 AF08

Claims (3)

[Claims] 1. A method for producing a glyoxylate-based polymer by polymerizing a monomer component containing a glyoxylate in the presence of a solvent to obtain a glyoxylate-based polymer and saponifying the polymer. The method for producing a glyoxylate polymer according to any one of claims 1 to 3, wherein a carboxylic acid ester is used as the solvent. 2. The method for producing a glyoxylate polymer according to claim 1, wherein the carboxylic acid ester has an alkoxycarbonyl having the same structure as the alkoxycarbonyl of the glyoxylate. 3. The method for producing a glyoxylate polymer according to claim 1, wherein the carboxylic acid ester is an acetic acid ester.