JP2002030112A - Anion exchange resin, method for producing the same, and method for preventing clamping using the same - Google Patents

Abstract

(57) [Problem] To provide an anion exchange resin which does not cause clamping when mixed with a cation exchange resin. SOLUTION: A crosslinked polymer having a haloalkyl group is reacted with a dithiocarbamic acid to convert the haloalkyl group into a dithiocarbamoylalkyl group, to which a vinyl compound is graft-polymerized in the presence of a radical polymerization initiator. The resulting haloalkyl group is reacted with an amine to form an anion exchange resin. The amine may be reacted before the graft polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an anion exchange resin. The anion exchange resin produced by the method of the present invention does not cause clamping even when mixed with the cation exchange resin, or has an excellent feature that the degree thereof is extremely small even if clamping occurs. .

[0002]

2. Description of the Related Art As one usage of an anion exchange resin, there is a method in which an anion exchange resin and a cation exchange resin are mixed in a free form and used as a mixed bed (MIXED BED). The mixed bed is often used when desalting a small amount of salts in water to a trace amount.
However, when the anion exchange resin and the cation exchange resin are mixed, development called clumping occurs in which the mixture lumps and swells. When clamping occurs, the mixing bed becomes uneven and the quality of the resulting demineralized water is significantly reduced. Also, even if backwashing is performed to regenerate the mixed bed, if clamping occurs, the anion exchange resin and the cation exchange resin do not separate well. As a result, regeneration is insufficient and the quality of demineralized water obtained from the regenerated mixed bed is significantly reduced.

Several methods for preventing clamping have been proposed. For example, JP-A-6-170248 discloses that by mixing fine iron oxide particles in water in which an ion exchange resin is immersed, and then blowing the air to mix the ion exchange resin with the fine iron oxide particles, Methods for preventing or eliminating clamping are described. JP-A-10-156194 discloses a method for preventing clamping by adding a water-soluble sulfonated polyvinyl aromatic compound having a number average molecular weight of 5 × 10 ³ to 1 × 10 ⁶ to an anion exchange resin. Has been described.

[0004]

However, since these methods are not based on the improvement of the ion exchange resin itself, the anti-clamping effect is reduced during long-term use, and the chemicals used in the treatment may reduce The quality of the resulting demineralized water may be reduced. Accordingly, an object of the present invention is to provide an anion-exchange resin which does not cause clamping or has a significantly small degree even if clamping occurs.

[0005]

According to the present invention, a dithiocarbamoylation step of reacting a crosslinked polymer having a haloalkyl group with a dithiocarbamic acid in a solvent, and a radical polymerization initiator are added to the reaction product of the dithiocarbamoylation step. By reacting a vinyl compound in the presence of a vinyl compound and an amination step of sequentially reacting a secondary or tertiary amine with a reaction product of the graft polymerization step by using an anion exchange resin. , Clamping can be prevented. Note that the order of the radical polymerization step and the amination step may be reversed so that the reaction product of the carbamoylation step is first reacted with a secondary or tertiary amine, and then the vinyl compound is reacted with the product. Good.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As a crosslinked polymer used as a base of the anion exchange resin according to the present invention, dextran
Examples thereof include those obtained by crosslinking natural polymers such as cellulose and chitosan with a crosslinking agent, and synthetic crosslinked polymers which are copolymers of a monovinyl compound such as an aromatic monovinyl compound or an alkyl (meth) acrylate with a polyvinyl compound. Usually, a synthetic cross-linking molecule is used. A styrene-divinylbenzene crosslinked copolymer or a crosslinked copolymer mainly composed of alkyl (meth) acrylate and alkylene glycol di (meth) acrylate, which is preferably used as a base of an ion exchange resin or a synthetic adsorbent. Is used. The crosslinked polymer may be either a gel type or a porous type.
The haloalkyl group only needs to have at least one halogen atom in the alkyl group, and in some cases, a substituent other than the halogen atom may be present. For example, chloromethyl, 2-chloroethyl, 3-
Examples thereof include a chloro-2-hydroxypropyl group and a 4-bromobutyl group. The haloalkyl group can be introduced into the crosslinked polymer later by an ordinary method, or can be introduced into the crosslinked polymer by the copolymerization reaction itself by using a monomer having a haloalkyl group for copolymerization.

The shape of the crosslinked polymer having a haloalkyl group may be plate-like, crushed granular, spherical, fibrous, pellet-like, sheet-like or the like depending on the use of the obtained anion exchange resin.
Although it can be of any shape, it is usually preferred to be spherical. The particle size is different for analytical or industrial use,
It is usually 1 μm to 2 mm, preferably 3 μm to 1.5 mm.

As the dithiocarbamic acids, those represented by the general formula (1) are used, and these are usually used in the reaction as salts such as ammonium salt, amine salt, sodium salt and zinc salt.

[0009]

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[0010] (wherein, R ^1, R ² is an alkyl group which may have a hydrogen atom or a substituent, a phenyl group, is a hydrocarbon group such as a benzyl group, bond and R ¹ and R ² Some examples of dithiocarbamic acid salts suitable for use in the method of the present invention include ammonium dithiocarbamate, sodium dimethyldithiocarbamate, and ammonium dimethyldithiocarbamate. , Zinc dimethyldithiocarbamate, sodium diethyldithiocarbamate, ammonium diethyldithiocarbamate, diethylammonium diethyldithiocarbamate, zinc diethyldithiocarbamate, sodium dibutyldithiocarbamate, zinc dibutyldithiocarbamate, pentamethylenedithiocarbamate Piperidine salt, ammonium tetramethylenedithiocarbamate, pipecoline salt of pipecolyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc dibenzyldithiocarbamate and the like. Among these, sodium dimethyldithiocarbamate, ammonium dimethyldithiocarbamate, ammonium diethyldithiocarbamate, ammonium diethyldithiocarbamate, sodium diethyldithiocarbamate, which have high solubility in water and are advantageous for reacting with a crosslinked polymer having a haloalkyl group as an aqueous solution It is preferable to use diethylammonium acid, sodium dibutyldithiocarbamate and the like.

The reaction of the crosslinked polymer having a haloalkyl group with a salt of a dithiocarbamic acid (this is referred to as a dithiocarbamoylation step in the present specification) involves the reaction of a crosslinked polymer having a haloalkyl group with a salt of a dithiocarbamic acid in a solvent. In addition, it easily proceeds by holding. As a solvent, does not dissolve the crosslinked polymer having a haloalkyl group,
Any one can be used as long as it can dissolve salts of dithiocarbamic acids. Usually, water is used, but an organic solvent can also be used. For example, alcohols such as methanol, ethanol, isopropanol, propylene glycol, ethylene glycol, and glycerin, and acetone, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, and dimethylformamide are used. The solvent may be used alone or as a mixed solvent. For example, a mixed solvent of the above organic solvent and water can be used.

The reaction temperature is usually from 0 to 200 ° C., and the reaction time is usually from 1 minute to 48 hours. The reaction is believed to proceed as follows.

[0013]

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(Wherein, P represents a crosslinked polymer, R represents an alkylene group, and X represents a halogen atom). That is, the dithiocarbamic acids react with the halogen atoms of the haloalkyl group of the crosslinked polymer to form the corresponding dithiocarbamoyl. It is believed that an alkyl group is formed. The ratio of the crosslinked polymer having a haloalkyl group to the dithiocarbamic acids to be subjected to the reaction is such that the amount of the dithiocarbamic acids is at least 0.3 mg, usually at least 0.5 mg per 1 g of the crosslinked polymer. If the amount of dithiocarbamic acids is too small,
The amount of dithiocarbamoylalkyl groups generated is small,
As a result, the amount of graft polymerization of the vinyl compound in the next step is reduced, and the obtained anion exchange resin does not exhibit the desired anti-clamping action. In order to obtain an anion exchange resin having a sufficient anti-clamping ability, it is preferable to subject the reaction to 1 mg or more, especially 3 mg or more of dithiocarbamic acids per 1 g of the crosslinked polymer having a haloalkyl group. Dithiocarbamic acids react with only a part of the haloalkyl groups present in the crosslinked polymer even when used in large amounts, and do not hinder subsequent reactions with secondary or tertiary amines. Dithiocarbamic acids are usually used in an amount of 50 mg per 1 g of the crosslinked polymer having a haloalkyl group, but if desired, a larger amount, for example, 5 g, may be used.
00 mg can also be used.

The crosslinked polymer in which a part of the haloalkyl group has been converted to a dithiocarbamoylalkyl group by the reaction with the above dithiocarbamic acids is then reacted with a vinyl compound in the presence of a radical polymerization initiator. In this reaction (hereinafter, referred to as a graft polymerization step), the dithiocarbamoyl group is decomposed, and graft polymerization occurs in which the polymer of the vinyl compound is bonded to the alkyl group of the dithiocarbamoylalkyl group via a sulfur atom. It is considered something.

[0016]

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The vinyl compound may be appropriately selected from known vinyl compounds which undergo graft polymerization in the presence of a radical polymerization initiator, but it is preferable to use a compound having no ion exchange group. Two or more vinyl compounds can be used in combination. Some examples of vinyl compounds suitable for use in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, and (meth) acrylic acid. (Meth) acrylates having no functional group such as tetrahydrofurfuryl; hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2,3-dihydroxypropyl (meth) acrylate, (meth) (Meth) acrylic esters having a hydroxyl group or an epoxy group such as glycidyl acrylate; (meth) acrylamides such as (meth) acrylamide and N, N-dimethyl (meth) acrylamide; styrene;
Styrenes such as methylstyrene, α-methylstyrene and chlorostyrene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether and octadecyl vinyl ether; allyl alcohol And esters and ethers thereof; and vinylamine derivatives such as N-vinylformamide and N-vinylacetamide. In addition, (meth) acrylonitrile,
(Meth) acrolein, N-vinylpyrrolidone and the like are also preferably used. Among these, it is preferable to use an alkyl (meth) acrylate or an alkyl vinyl ether which may have a hydroxyl group.

As the radical polymerization initiator, 2,2'-
Azo-based polymerization initiators such as azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), and 4,4'-azobis (4-cyanopentanoic acid); t-butyl hydroperoxide; Organic peroxide-based polymerization initiators such as di-t-butyl peroxide, benzoyl peroxide, diisopropyl peroxydicarbonate and t-butyl peroxyisobutyrate; and inorganic peroxides such as hydrogen peroxide, potassium persulfate and ammonium persulfate It is possible to use a conventional polymerization initiator such as a product-based polymerization initiator or a combination thereof with a reducing agent such as an amine or sodium bisulfite.

The radical polymerization may be carried out by adding the above-mentioned crosslinked polymer having a dithiocarbamoyl group to a solution in which a radical polymerization initiator and a vinyl compound are dissolved. The polymerization initiator is 0.01 to
About 10% by weight may be used. The reaction temperature is usually 0.
To 200 ° C., and the polymerization time is preferably about the half-life of the polymerization initiator or longer, and is usually about 3 to 48 hours. The amount of polymerization per unit amount of crosslinked polymer is usually 0.1.
It is about 01 to 200% by weight. Any reaction solvent can be used as long as it is inert to the reaction, dissolves the vinyl monomer and the polymerization initiator, and does not dissolve the crosslinked polymer having a carbamoyl group bonded thereto. Usually, alcohols such as methanol, ethanol, isopropanol, diethylene glycol, propylene glycol, and glycerin; methyl formate, ethyl formate, methyl acetate,
Esters such as ethyl acetate and ethylene glycol monoacetate; ethers and ether alcohols such as diethyl ether, dioxane, tetrahydrofuran, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone;
Hydrocarbons such as hexane, cyclohexane, octane, benzene, toluene and xylene; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene, dichlorobenzene and chlorotoluene; acetonitrile, dimethylformamide, pyridine And nitrogen-containing compounds such as nitrobenzene, and sulfur-containing compounds such as carbon disulfide and dimethylsulfoxide. Water can be used as the solvent. Two or more of these solvents can be used in combination.

The crosslinked copolymer having a vinyl compound graft polymer formed on the surface by radical polymerization is then reacted with a secondary or tertiary amine. By this reaction (this is referred to as an amination step in the present specification), the haloalkyl group remaining in the crosslinked copolymer is converted into an anion exchange group. As the secondary amine or the tertiary amine, it is preferable to use an alkylamine composed of an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, such as trimethylamine, triethylamine, dimethylamine, diethylamine and dimethylethanolamine. Usually, trimethylamine or dimethylethanolamine is used. The reaction is
According to a conventional method of producing an anion exchange resin by reacting these alkylamines with a crosslinked copolymer having a haloalkyl group, the crosslinked copolymer having undergone graft polymerization is suspended in a solvent, and the amine is added to the suspension. ~ 120 ° C for 1 minute ~
The reaction may be performed for about 40 hours. As the solvent, water, methanol, ethanol, toluene, dioxane, dimethylformamide, dichloroethane, or the like may be used alone or as a mixture.

The anion exchange resin according to the present invention comprises:
In the above production method, the order of the graft polymerization step and the amination step is reversed, and the crosslinked polymer having the dithiocarbamoyl group introduced therein is first reacted with an amine to introduce an anion exchange group, and then the graft polymerization of a vinyl compound is carried out. And graft polymerization of a vinyl compound on the surface. Also in this case, the introduction of the anion exchange group and the graft polymerization of the vinyl compound can be performed under the same conditions as described above. If further desired,
Amination and graft polymerization can be performed simultaneously.

[0022]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples. Example 1 In a reactor equipped with a stirrer and a condenser, a chloromethylated styrene-divinylbenzene copolymer (divinylbenzene content 4.6% by weight, gel type, particle size 300 to
1180 μm), 150 mg of sodium diethyldithiocarbamate trihydrate and 150 g of demineralized water were charged. After reacting at 90 ° C. for 4 hours, the mixture was filtered and washed with water to obtain a resin having a diethyldithiocarbamoyl group introduced.

In a reactor equipped with a stirrer and a condenser,
The total amount of the resin obtained above, 38 ml of toluene, 4 parts of demineralized water
5 ml and 33 ml of a 30% aqueous solution of trimethylamine were charged and reacted at 50 ° C. for 8 hours to trimethylaminate the chloromethyl group remaining on the resin. After filtration and washing with water, a resin in which the chloromethyl group was trimethylaminated was obtained.

In a reactor equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet tube, the total amount of the trimethylaminated resin obtained above, 6.0 g of hydroxyethyl methacrylate, 150 mg of potassium persulfate and 150 m of demineralized water were added.
l was charged. The reaction was carried out at 80 ° C. for 6 hours to obtain a strongly basic anion exchange resin having poly (hydroxyethyl methacrylate) on the surface. Its water content is 39.9%
The ion exchange capacity was 1.20 meq / ml-wet resin. Comparative Example 1 In Example 1, styrene having a chloromethyl group was used.
Trimethylamine was reacted in the same manner as in Example 1 without introducing a diethyldithiocarbamoyl group into the divinylbenzene copolymer to perform trimethylamination of the chloromethyl group. It has a water content of 45.7%
The ion exchange capacity was 1.43 meq / ml-wet resin. Example 2 The procedure of Example 1 was repeated, except that the amount of sodium diethyldithiocarbamate trihydrate was changed to 600 mg, the introduction of a diethyldithiocarbamoyl group was performed, and the remaining chloromethyl group was trimethylaminated. And graft polymerization of hydroxyethyl methacrylate.
The water content of the obtained strongly basic anion exchange resin is 39.5.
In%, the ion exchange capacity was 1.21 meq / ml-wet resin. Example 3 The procedure of Example 1 was repeated, except that the charged amounts of sodium diethyldithiocarbamate trihydrate were 75 mg, and the charged amounts of hydroxyethyl methacrylate and potassium persulfate were 1.5 g and 40 mg, respectively. In the same manner as in 1, the introduction of a diethyldithiocarbamoyl group, the trimethylamination of the remaining chloromethyl group, and the graft polymerization of hydroxyethyl methacrylate were performed. The obtained strongly basic anion exchange resin had a water content of 44.4% and an ion exchange capacity of 1.32 meq / ml-wet resin. Example 4 The total amount of the resin into which the diethyldithiocarbamoyl group was introduced and obtained in the same manner as in Example 1, 6.0 g of isobutyl vinyl ether, 150 mg of 2,2'-azobis (2,4-dimethylvaleronitrile), and Ethanol 150
ml was charged into a reactor equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet tube. The reaction was carried out at 70 ° C. for 6 hours to obtain a resin having poly (isobutyl vinyl ether) on the surface.

In a reactor equipped with a stirrer and a condenser,
The total amount of the resin obtained above, 38 ml of toluene, 4 parts of demineralized water
5 ml and 33 ml of a 30% aqueous solution of trimethylamine were charged and reacted at 50 ° C. for 8 hours to trimethylaminate remaining chloromethyl groups. The obtained strongly basic anion exchange resin had a water content of 46.8% and an ion exchange capacity of 1.36 meq / ml-wet resin. Example 5 In Example 4, isobutyl vinyl ether and 2,
Graft polymerization of isobutyl vinyl ether and removal of residual chloromethyl groups were performed in the same manner as in Example 4 except that the charged amounts of 2'-azobis (2,4-dimethylvaleronitrile) were changed to 3.0 g and 75 mg, respectively. Trimethyl amination was performed. The obtained strongly basic anion exchange resin has a water content of 47.1% and an ion exchange capacity of 1.36.
Meq / ml-wet resin. Clamping test; 10 ml of H-type commercially available strongly acidic cation exchange resin (Mitsubishi Chemical Corporation, Diaion SKIB, Diaion is a registered trademark of Mitsubishi Chemical Corporation),
10 ml of the OH type of the strongly basic anion exchange resin obtained above was mixed in room temperature water, and the volume was measured. The results are shown in Table 1.

[0026]

[Table 1]

As is clear from Table 1, the anion exchange resin according to the present invention does not cause clamping even when mixed with the cation exchange resin. Although the details of the reason are unknown, it is considered that the graft polymer formed on the surface physically separates the exchange group of the anion exchange resin from the exchange group of the cation exchange resin. In addition,
In the above experiment, only the anion exchange resin according to the present invention was used. However, if desired, the anion exchange resin may be used in combination with another anion exchange resin.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08F 257/00 C08F 257/00 F term (Reference) 4J026 AA18 AA19 AA21 AC26 BA05 BA06 BA12 BA14 BA16 BA19 BA20 BA27 BA30 BA32 BA37 BA39 BA40 CA04 CA05 DB03 DB12 DB14 DB15 EA09 FA09 GA08 4J100 AB02P AB16Q BA29H BA31H BA51H CA04 HA25 HC43 HC69 JA16

Claims (9)

[Claims] 1. A dithiocarbamoylation step in which a crosslinked polymer having a haloalkyl group and a dithiocarbamic acid are reacted in a solvent, and a graft reaction in which a vinyl compound is reacted with a reaction product of the dithiocarbamoylation step in the presence of a radical polymerization initiator. A method for producing an anion exchange resin, which comprises sequentially performing a polymerization step and an amination step of reacting a reaction product of a graft polymerization step with a secondary or tertiary amine. 2. A dithiocarbamoylation step of reacting a crosslinked polymer having a haloalkyl group with a dithiocarbamic acid in a solvent, an amination step of reacting a reaction product of the dithiocarbamoylation step with a secondary or tertiary amine, and A method for producing an anion exchange resin, comprising sequentially performing each step of a graft polymerization step in which a vinyl compound is reacted with a reaction product of an amination step in the presence of a radical polymerization initiator. 3. The method according to claim 1, wherein the crosslinked polymer is a copolymer of an aromatic monovinyl compound and a divinyl compound.
A method for producing the anion exchange resin according to claim 1. 4. The method for producing an anion exchange resin according to claim 1, wherein the dithiocarbamic acid is subjected to the reaction as a salt. 5. The method for producing an anion exchange resin according to claim 1, wherein the vinyl compound is an alkyl (meth) acrylate optionally having a hydroxy group. 6. The method for producing an anion exchange resin according to claim 1, wherein the vinyl compound is an alkyl vinyl ether. 7. The method according to claim 1, wherein the secondary or tertiary amine is an alkylamine comprising an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group. A method for producing the anion exchange resin according to the above. 8. An anion exchange resin obtained by the production method according to claim 1. 9. The method of mixing an anion exchange resin and a cation exchange resin to form a mixed bed, wherein the anion exchange resin according to claim 8 is used as at least a part of the anion exchange resin. How to prevent floor clamping.