JP4682702B2 - Cation analysis ion chromatography column and method for producing the same - Google Patents

Description

  The present invention relates to a column for ion chromatography, in particular, a column for ion analysis ion chromatography. More specifically, the present invention relates to a weakly acidic cation exchange column and a column for simultaneous analysis of monovalent and divalent cations.

Conventionally, ion chromatography has been used for analysis of inorganic ions, and recently, due to its simplicity, it has been heavily used for environmental water, nuclear and semiconductor-related industrial water, and atmospheric ion analysis.
Ion chromatography that separates and analyzes monovalent and non-monovalent cations is a strongly acidic ion in which a sulfonic acid group is chemically bonded to a styrene / divinylbenzene copolymer or a propylsulfonic acid group is chemically bonded to silica gel. Exchangers have been widely used. However, in columns using these strongly acidic ion exchangers, heavy metal ions mixed in the sample are adsorbed on the ion exchanger and adversely affect the original analysis, or divalent cations other than monovalent ions and heavy metal ions. Therefore, there is a problem that monovalent and non-monovalent cations cannot be measured simultaneously under the same elution conditions (see, for example, Non-Patent Document 1). ).

In recent years, as a weakly acidic cation exchanger that solves this problem, a weakly acidic cation exchanger in which a polybutadiene maleic acid film (4: 1 molar ratio) containing 4% dicumyl peroxide is formed on a silica gel surface is used. (See Non-Patent Document 2).
In this ion chromatography using a weakly acidic cation exchanger, monovalent and divalent cations can be separated and analyzed at the same time using an organic acid that is a weak acid as the eluent. There is a problem that later elution of divalent cations is slow.

Therefore, as a device for improving this method, pyridine-2,6-dicarboxylic acid is added to the eluent using the same cation exchanger to form a complex with the divalent cation, thereby forming a divalent cation. A method for selectively reducing the retention capacity ratio and shortening the measurement time has been announced (see Non-Patent Document 3). In addition, a weakly acidic cation exchanger in which a polybutadiene maleic acid and a polyvinyl compound such as triallyl isocyanurate serving as a crosslinking agent are reacted in order to prevent detachment of the coated polymer has been announced (see Patent Document 1). ).
Furthermore, there is also a weak cation exchanger in which an ion exchange group is introduced by hydrolyzing a glycidyl group of particles containing a glycidyl group and reacting the hydroxyl group with a polybasic acid compound.
A general method for producing a cation exchanger has been proposed in Patent Document 2, for example.
Edited by Kanto Branch, Analytical Society of Japan, High Performance Liquid Chromatography Handbook (Maruzen) Chromatography, Vol. 23, no. 7, p465-472 Am. Lab. (Fair field Conn.) Vol. 21, no. 5, p92-101 JP-A-5-96184 JP-A-11-156216

  However, a weakly acidic cation exchange column produced by these methods has a divalent cation (especially ammonium / sodium) separation when the acid concentration of the eluent is as low as 5 mM or less. There is a problem that ion elution is delayed.

  The present invention provides an eluent to which a special reagent such as pyridine-2,6-dicarboxylic acid or 18-C-6 crown ether is added, a special eluent composed of a plurality of acids, or a high concentration of 10 mM to 20 mM. Concentration eluent is not required, monovalent and divalent cations are well-balanced, that is, it is particularly excellent in ammonium / sodium separation without impairing the separation of monovalent cations, and after separation of monovalent cations, Provided is a column in which a divalent cation can be separated and analyzed in a short time without the monovalent cation and divalent cation separating too much.

（ただし、一般式（II）中、ｎは１〜５の整数、Ｒは水素原子またはアルキル基を示す。） The present invention relates to a column for cation analysis ion chromatography wherein the quotient of the retention time of ammonium / sodium / calcium represented by the following formula (I) eluted at an acid concentration of 0.5 mM to 5.0 mM is 0.05 or more.
TNH ₄ / TNa / TCa (I)
(However, in formula (I), TNH ₄ represents the retention time of ammonium, TNa represents the retention time of sodium, and TCa represents the retention time of the slower elution with calcium and magnesium.)
Such a column for cation analysis ion chromatography can be achieved, for example, by heat treating the cation exchanger packed in the column with a vacuum dryer at a vacuum degree of 700 mmHg to 760 mmHg, 70 ° C to 120 ° C, 5 hours to 150 hours. .
The exchange group of the cation exchanger is preferably a structure of the general formula (II).

(In the general formula (II), n represents an integer of 1 to 5, and R represents a hydrogen atom or an alkyl group.)

  According to the present invention, in a column for cation analysis ion chromatography, a special eluent or a high concentration eluent is not required, and the monovalent and divalent cations are well balanced, that is, the monovalent cation separation ability is impaired. And a column excellent in ammonium / sodium separation can be provided. In addition, a column capable of separating and analyzing divalent cations in a short time without separating monovalent cations and divalent cations after separation of monovalent cations can be provided.

  The conditions of ion chromatography are not particularly limited, but when the acid concentration of the eluent is higher than 5 mM, the balance of monovalent and divalent cations is relatively better than that of 5 mM or less. Usually, a device such as a suppressor is required because of the background of According to the present invention, the monovalent and divalent cations are balanced in a low acid concentration that can be used for ion chromatography without an apparatus such as a suppressor, that is, 0.5 mM to 5.0 mM, preferably 0.5 mM to 3.0 mM. In other words, the ammonium / sodium separation is particularly excellent without impairing the separation ability of the monovalent cation. After the monovalent cation is separated, the monovalent cation and the divalent cation are not separated from each other. Provides a column that can be separated and analyzed in a short time. If a low concentration acid of less than 0.5 mM is used as the eluent, the elution power is insufficient, and the retention of divalent cations becomes longer or does not elute.

As an evaluation of the elution balance of monovalent cation / divalent cation, the ratio of the retention time of ammonium to the retention time of calcium and the retention time of sodium are shown as the quotient of the retention time of ammonium / sodium / calcium.
Specifically, the larger the quotient of the following formula (I), the better the separation of sodium and ammonium, indicating that the monovalent cation and divalent cation are not separated.
TNH ₄ / TNa / TCa (I)
(However, in formula (I), TNH ₄ represents the retention time of ammonium, TNa represents the retention time of sodium, and TCa represents the retention time of the slower elution with calcium and magnesium.)
The present invention can provide a column for cation analysis ion chromatography in which the quotient of the retention time of ammonium / sodium / calcium is 0.05 or more. The TCa is usually a calcium retention time in many cases. The quotient value of formula (I) is preferably 0.06 or more.

  When the cation exchanger is heat-treated in a vacuum dryer at a vacuum of 700mmHg to 760mmHg and a temperature of 70 ° C to 120 ° C, the retention time of divalent cations such as magnesium and calcium can be shortened in proportion to the heat treatment time, and ammonium and sodium The retention time of monovalent cations such as is not so shortened. This is presumably because the large pores of the ion exchanger in the column are crushed by the vacuum drying heat treatment, and divalent cations having a large ionic radius are not retained in the pores. As a result, when this treatment method is used, a cation analysis column can be produced in which the quotient of the retention time of ammonium / sodium / calcium to be eluted is 0.05 or more even when the acid concentration of the eluent is 0.5 mM to 5.0 mM. When the degree of vacuum is less than 700 mmHg, the retention time of divalent cations tends to be slow. Similarly, even when the temperature is less than 70 ° C., the reduction of the retention time of the divalent cation is slow, and when it exceeds 120 ° C., the ion exchanger gel may be decomposed or the exchange group may be eliminated. Therefore, the heat treatment temperature is more preferably 70 ° C to 90 ° C.

  The heat treatment time can be adjusted between 5 and 150 hours while checking the retention time of the divalent cation and the balance of the monovalent cation and the bivalent cation (a quotient of the retention time of ammonium / sodium / calcium). If it is less than 5 hours, the effect of the heat treatment is small, and if it exceeds 150 hours, decomposition of the ion exchanger, elimination of exchange groups, etc. easily occur.

  The cation exchanger packed in the column preferably has a polyvalent carboxylic acid for simultaneous analysis of monovalent and divalent cations, and has the structure of the above general formula (II). Is more preferable. In general formula (II), n is an integer of 1 to 5, and R is a hydrogen atom or an alkyl group. R is preferably a methyl group or an ethyl group.

Elution balance of monovalent and divalent cations, that is, since separation of monovalent ions can be performed in a short time without separation of monovalent ions without impairing ion separation, The number n of —COOR groups in the formula (II) is preferably 2 or more and 5 or less. More preferably, n is 2.
In the present invention, as a particularly preferred cation exchanger, in the ion exchange group represented by the general formula (II), from the elution balance of monovalent and divalent cations, the number of —COOR groups in the formula n Is preferably 2 or more and 5 or less, and preferably has at least one positional relationship in which —COOR groups are bonded to adjacent carbon atoms.

The production method of the cation exchanger packed in the column is not particularly limited, and can be produced by a known general cation exchanger production method.
Below, a preferable manufacturing method in case a cation exchanger is what the ion exchange group represented by general formula (II) couple | bonded with the polymer particle through the ether bond is demonstrated. Here, the polymer particles are formed by a reaction of a polymerizable carbon-carbon double bond in a polymerizable monomer other than an ion exchange group. In the present invention, suspension polymerization, dispersion polymerization, soap-free polymerization or the like is used as the polymerization or copolymerization method. Suspension polymerization is more preferable from the viewpoint of ease of polymerization, but is not limited thereto.

（ただし、一般式（III）、（IV）中、Ｒは一般式（II）と共通であり、ｎは１〜５の整数を示し、Ｘは炭素数４以下のハロアルキル基を示す。） The method for producing a cation exchanger in the present invention includes a polymerizable monomer containing a polymerizable monomer having a functional group reactive with a hydroxyl group or an X group in a compound represented by the following general formula (III) or (IV). Examples include a method in which a monomer is polymerized or copolymerized to produce polymer particles, and then a compound represented by the general formula (III) or (IV) is reacted therewith. Examples of the functional group reactive with the hydroxyl group or the X group include groups such as glycidyl group, hydroxyl group, and halogen, and at least one kind is used. By this production method, the group represented by the general formula (II) can be introduced into the polymer particles.
Moreover, a non-crosslinkable polymerizable monomer having an ion exchange group represented by the general formula (II) can be copolymerized with other copolymerization components to produce a cation exchanger.
Furthermore, the ion-exchange group having the structure of the general formula (II) is directly bonded to the polymerizable particle having the reactive functional group, or the polymerizable particle in which glycidyl group or the like is introduced by reacting with epichlorohydrin after polymerization by an ether bond. It can also be introduced.

(However, in general formulas (III) and (IV), R is the same as in general formula (II), n represents an integer of 1 to 5, and X represents a haloalkyl group having 4 or less carbon atoms.)

In the present invention, it is preferable to use a non-crosslinkable polymerizable monomer and a crosslinkable polymerizable monomer in combination with the polymer particles.
The non-crosslinkable polymerizable monomer used for the cation exchanger is a monomer having one polymerizable carbon-carbon double bond in one molecule. Styrenic, acrylic and methacrylic non-crosslinkable polymerizable monomers may be mentioned. Examples of the derivatives of these non-crosslinkable polymerizable monomers include derivatives having a hydroxyl group, a glycidyl group, a halogen, an alkyl group, an alkyloxy group, an aryloxy group, an aralkyloxy group, and the like. .

  In the non-crosslinkable polymerizable monomer having a halogen or glycidyl group which is a functional group reactive with a hydroxyl group of the compound represented by the general formula (III), a styrene derivative having a halogen includes a hydrogen atom of styrene as chlorine. And those substituted with atoms such as bromine and substituted with side chains of an aromatic ring such as chloromethylstyrene are preferred. For example, chloromethyl styrene, dichloromethyl styrene, pentabutyl chlorostyrene and the like, and halogenated derivatives obtained by changing these chloro to bromo, and the like can be mentioned. Examples of the derivative of the acrylic ester having halogen include chloromethyl methacrylate, chloroethyl methacrylate, chlorobutyltyl methacrylate, and the like.

  Examples of styrene derivatives having a glycidyl group include vinyl benzyl glycidyl ether and vinyl benzyl glycidyl ester. Examples of the acrylic acid and methacrylic acid derivatives having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, glycidyl clonate, glycidyl itaconate, glycidyl fumarate, glycidyl malate, and the like.

  In the non-crosslinkable polymerizable monomer having a hydroxyl group or a glycidyl group which is a functional group reactive with the X group of the compound represented by the general formula (IV), the styrene derivative having a hydroxyl group may have a hydroxyl group of 1 to 5 These may include styrene, and may have other hydrocarbon groups other than hydroxyl groups. Examples thereof include monohydroxy styrene, dihydroxy styrene, pentahydroxy styrene, monomethyl hydroxy styrene, pentaethyl hydroxy styrene, monopropyl hydroxy styrene, pentabutyl hydroxy styrene and the like.

  Examples of the derivatives of acrylic acid and methacrylic acid having a hydroxyl group include hydroxyethyl acrylate, hydroxypropyl acrylate, neopentyl glycol monoacrylate, tetramethylol methane triacrylate, 2-hydroxyethyl acrylate, and hydroxy methacrylate. Examples include propyl, neopentyl glycol monomethacrylate, and tetramethylol methane trimethacrylate. Examples of styrene derivatives having a glycidyl group include vinyl benzyl glycidyl ether and vinyl benzyl glycidyl ester. Examples of the acrylic acid and methacrylic acid derivatives having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, glycidyl clonate, glycidyl itaconate, glycidyl fumarate, glycidyl malate, and the like.

  In the non-crosslinkable polymerizable monomer having no functional group reactive with the hydroxyl group or X group of the compound represented by the general formula (III) or (IV), the styrene derivative having an alkyl group may have 1 carbon atom. Examples include styrene having 1 to 5 hydrocarbons such as -4 alkyl groups or alkenyl groups, and specific examples include α-methylstyrene, dimethylstyrene, vinyltoluene, pt-butylstyrene, and the like.

  Examples of the derivatives of acrylic acid and methacrylic acid having an alkyl group include methyl acrylate, ethyl acrylate, dodecyl acrylate, methyl methacrylate, undecyl methacrylate, dodecyl methacrylate, and the like.

  Examples of the derivatives of acrylic acid and methacrylic acid having an alkyloxy group include methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydipropylene glycol acrylate, methoxyethyl methacrylate, putoxytriethylene glycol methacrylate, and methoxy methacrylate. Examples include dipropylene glycol.

  Examples of those having an aryloxy group or an aralkyloxy group include phenoxyethyl acrylate, phenoxytetraethylene glycol acrylate, benzyl acrylate, cyclohexyl acrylate, and tetrahydrofurfuryl methacrylate. Other examples include dicyclopentenyl acrylate, dicyclopentenyloxyethyl methacrylate, and N-vinyl-2-pyrrolidone acrylate. Examples of other non-crosslinkable polymerizable monomers include acrylonitrile, methacrylamide, N-methylol acrylamide, diacetone acrylamide, vinyl pyridine and the like. These are not limited to the above specific examples, and several of them can also be mixed.

  More preferably, it has a structure having an ion exchange group represented by the general formula (II) and linked by an ether bond from the viewpoint of easy and efficient production without introducing an ion exchange group after polymerization. Non-crosslinkable polymerizable monomers are desirable. For example, phthalic acid vinyl ether, phthalic acid 1-methyl vinyl ether, hydroxyphthalic acid vinyl ether, hydroxyphthalic acid 1-methyl vinyl ether, trimellitic acid vinyl ether, trimellitic acid 1-methyl vinyl ether, pyromellitic acid vinyl ether, pyromellitic acid 1-methyl Examples include vinyl ethers and derivatives thereof. It is not limited to these specific examples, Furthermore, these can be used 1 type or in combination of 2 or more types.

  The crosslinkable polymerizable monomer used in the present invention may be any monomer as long as it has two or more polymerizable groups in one molecule. Examples of monomers having two polymerizable groups in one molecule include divinylbenzene, glycol and methacrylic acid or acrylic acid diesters such as ethylene glycol dimethacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, 1 , 6-hexanediol diacrylate, neopentyl glycol dimethacrylate, tripropylene glycol diacrylate, trimethylol propane dimethacrylate, tetramethylol methane diacrylate, polypropylene glycol diacrylate, etc., and 3 or more polymerizations per molecule Examples of monomers having a functional group include trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolethane trimethacrylate. Rate, pentaerythritol tetraacrylate, and the like. However, the present invention is not limited to these specific examples, and several of them can be mixed.

In the non-crosslinkable polymerizable monomer and the crosslinkable polymerizable monomer in the present invention, the above-mentioned non-crosslinkable polymerizable monomer in terms of ease of ion exchange group introduction, ease of filling into the column, column durability, etc. The solubility parameter (SP value) of the polymer particles calculated from the blending ratio of the polymer and the crosslinkable polymerizable monomer is preferably 9.5 to 14 (cal / cm ³ ) ^1/2 . More preferably, it is 9.7 to 13.5 (cal / cm ³ ) ^1/2 , and more preferably 10.0 to 13.0 (cal / cm ³ ) ^1/2 of hydrophilic polymer particles. is there. In cation exchangers in which COOR groups are introduced into polymer particles having an SP value of less than 9.5, hydrophobicity tends to be strong, and separation other than ion exchange acts or filling in aqueous systems tends to be difficult. There is. When the SP value is larger than 14, the hydrophilicity of the polymer particles becomes too strong, the degree of swelling of the polymer particles with respect to the aqueous solution increases, and there is a tendency that the polymer particles do not function as a packing material for ion chromatography.

  The solubility parameter of the polymer particles can be adjusted using a polymerizable monomer having the SP value shown below. For example, it contains hydroxyl groups such as 2-hydroxyethyl (meth) acrylate (SP value: 12.3), 4-hydroxybutyl (meth) acrylate, neopentyl glycol mono (meth) acrylate, tetramethylol methanetri (meth) acrylate, etc. Epichloroform is obtained by copolymerizing a non-crosslinkable polymerizable monomer or a crosslinkable polymerizable monomer and a crosslinkable polymerizable monomer such as ethylene glycol dimethacrylate (SP value: 10.4). A glycidyl group-containing non-crosslinkable polymerizable monomer such as glycidyl group introduced by reacting hydrin or the like, glycidyl (meth) acrylate (SP value: 10.7), and ethylene glycol dimethacrylate (SP value: And those obtained by copolymerization with a crosslinkable polymerizable monomer such as 10.4).

The polymerization ratio between the non-crosslinkable polymerizable monomer and the crosslinkable polymerizable monomer for obtaining polymer particles is preferably 90 to 30% by weight: 10 to 70% by weight. If the crosslinkable polymerizable monomer is less than 10% by weight, the resulting weakly acidic ion exchange resin has poor mechanical strength, poor durability in repeated use, and stable separation analysis tends to be impossible. In addition, when the crosslinkable polymerizable monomer exceeds 70% by weight, the pore diameter tends to be difficult to adjust in some cases. In the polymerization or copolymerization for obtaining the polymer particles, other known non-crosslinkable polymerizable monomers and crosslinkable polymerizable monomers can be used for copolymerization as necessary.
In the polymerization or copolymerization for obtaining polymer particles, the non-crosslinkable polymerizable monomer and / or the crosslinkable polymerizable monomer as described above may be an inert organic solvent such as dimethyl sulfoxide, It is preferably dissolved in xylene, toluene, dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, acetone, tetrahydrofuran or the like.

  The polymer particles are preferably polymerized in an aqueous medium. The aqueous medium is basically used to emulsify and disperse the oil droplets that are the basis of the polymer particles to a desired size, and the amount depends on the type and amount of the monomer, so it is generally determined. Although it is not, it is preferable that it is 80-400 weight part with respect to 100 weight part of polymerizable monomers. If it is less than 80 parts by weight, the viscosity of the emulsified dispersion tends to increase, and it tends to be difficult to adjust the desired oil droplets. If it exceeds 400 parts by weight, the yield of polymer particles per production batch is deteriorated, resulting in productivity. There may be a problem such as lowering of the level. A dispersant such as gelatin, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, or hydroxyapatite can be used to stabilize the oil droplets of the monomer and organic solvent in the medium.

Some of the above dispersants do not sufficiently exhibit their functions, and it is effective to add a dispersion aid. As the dispersion aid, generally known surfactants, cationic, anionic, and nonionic surfactants are used, and among these, anionic surfactants are particularly preferable. Examples of the anionic surfactant include sodium alkylbenzene sulfonate, sodium α-olefin sulfonate, sodium alkyl sulfonate, and metal salts thereof. The anionic surfactant is preferably added in an amount of 1 × 10 ^{−4 to} 0.1% by weight based on the aqueous medium. If it is less than 1 × 10 ⁻⁴ wt%, the function as a dispersion aid tends to be difficult to develop, and if it exceeds 0.1 wt%, it itself functions as a dispersant or an emulsifier, and good suspension polymerization. There is a tendency that cannot be done.

  The polymerization initiator used for polymerization or copolymerization is preferably a peroxide radical initiator or an azo radical initiator, such as benzoyl peroxide, 2-ethylhexyl perbenzoate, acetyl peroxide, acetone di-tert. -Peroxide-based radical polymerization initiators such as butyl peroxy ketal and diisopropyl hydroperoxide, and azo polymerization initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2-methylpropane) Is mentioned.

  The radical polymerization initiator is preferably used in an amount of 0.05 to 10 parts by weight with respect to 100 parts by weight of the monomer having one polymerizable group. When the amount used is less than 0.05 parts by weight, the polymerization time tends to be long, and unreacted monomers tend to remain in the polymer fine particles. On the other hand, when the amount used exceeds 10 parts by weight, not only the polymerization initiator is wasted, but also heat generation control during polymerization tends to be difficult and problems such as insufficient molecular chain length tend to occur.

  Since the cation exchanger in the present invention has porosity, various solvents may be added as a pore regulator during the polymerization. The solvent serving as the pore regulator may be the same as the above-described inert organic solvent. This solvent is soluble in the polymerizable monomer and does not dissolve the polymer. Specifically, toluene, xylene, ethylbenzene, diethylbenzene, heptanol, isoamyl alcohol, ethyl acetate, butyl acetate, dimethyl phthalate, Known ones such as aliphatic or aromatic esters such as diethyl phthalate, ethylene glycol monoethyl ether acetate, hexane, octane and decane can be used. These may be properly used depending on the type of monomer from which the polymer is obtained, and may be used alone or in combination. The mixing ratio of these solvents is preferably 5 to 300% by weight, more preferably 20 to 200% by weight, and still more preferably 50 to 100% by weight based on the total amount of the polymerizable monomers in terms of porosity. Is done. If the blending ratio is less than 5% by weight or exceeds 300% by weight, it becomes difficult to obtain desired porosity, and the resulting polymer tends to have poor pressure resistance.

The amount of —COOR group, which is an ion exchange group finally introduced into the cation exchanger in the present invention, is preferably 0.5 to 7.0 meq / g, more preferably 1.0 to 6. 0.5 meq / g, more preferably 1.5 to 6.5 meq / g, and particularly preferably 1.5 to 6.0 meq / g. Exchange capacity is defined as the amount of -COOR groups in the dried cation exchanger. When the exchange capacity is less than 0.5 meq / g, after elution of monovalent ions (Li ⁺ , Na ⁺ , NH ₄ ⁺ , K ⁺ ), divalent ions (Mg ²⁺ , Ca ²⁺ ) Elution tends to be slow and is not practical. Also, if it exceeds 7.0 milliequivalent / g, the ion component as a separation analysis component is strongly adsorbed on the cation exchanger and it takes an extremely long time to elution, or the eluent concentration is increased to elution the ion component. If the measurement is made easier, the reference line (background) of the ion chromatogram becomes higher, and the detection sensitivity of the target ions tends to be lowered and separation analysis cannot be performed.

  In order to introduce the structure of the general formula (II) into the polymer particles by an ether bond, the compound represented by the general formula (III) or the general formula (IV) is used after once producing the polymerizable particles. It is preferable to react. When the functional group of the polymer particle is halogen, the hydroxyl group of the compound represented by the general formula (III) can be reacted. When the functional group of the polymer particle is a hydroxyl group, the functional group is represented by the general formula (IV). The halogen of the haloalkyl group of the compound can be reacted. When the functional group of the polymer particle is a glycidyl group, the hydroxyl group or halogen of the compound represented by the general formula (III) or the general formula (IV) can be reacted. In the compound having a —COOR group represented by general formula (III) and general formula (IV), R is the same as R in general formula (II).

  Examples of the compound represented by the general formula (III) include hydroxybenzoic acid or an esterified product thereof, hydroxyphthalic acid or an esterified product thereof, and specifically, hydroxybenzoic acid, dihydroxybenzoic acid, trihydroxybenzoic acid. Examples thereof include acids, tetrahydroxybenzoic acid, hydroxyphthalic acid, dihydroxyphthalic acid, tetrahydroxyphthalic acid, hydroxytrimellitic acid, dihydroxytrimellitic acid, hydroxypyromellitic acid, and derivatives of these esters. In particular, esterified products of phthalic acid, trimellitic acid, and pyromellitic acid having one or more structures in which the carboxyl groups are adjacent to each other are preferable. The amount of the compound of the general formula (III) is not particularly limited, but 0.3 mM to 100 mM is suitable for 1 g of the polymerizable particles.

  Examples of the compound represented by the general formula (IV) include chloromethylbenzoic acid and the like or esterified products thereof, chloromethylphthalic acid or the esterified products thereof, and specifically include chloromethylbenzoic acid and dichloromethylbenzoic acid. , Trichloromethylbenzoic acid, tetrachloromethylbenzoic acid, chloromethylphthalic acid, dichloromethylphthalic acid, tetrachloromethylsiphthalic acid, chloromethyltrimellitic acid, dichloromethyltrimellitic acid, chloromethylpyromellitic acid, etc. Derivatives of these esters are mentioned. Among these, derivatives of esters of phthalic acid, trimellitic acid, and pyromellitic acid having one or more structures in which the carboxyl groups are adjacent to each other are preferable. The amount of the compound of the general formula (IV) is not particularly limited, but 0.3 mM to 100 mM is suitable for 1 g of the polymerizable particles.

  As a solvent for dissolving the compound represented by the above general formula (III) or general formula (IV), there is no particular limitation as long as it is a solvent that can be dissolved and does not react with the above compound, and generally dimethyl sulfoxide, xylene, toluene, dioxane. , N, N-dimethylformamide, N, N-dimethylacetamide, acetone, tetrahydrofuran, and other organic solvents. The reaction temperature as a condition for introducing and adding the compound represented by formula (III) or formula (IV) is not particularly limited as long as it is not lower than the melting point and not higher than the boiling point of the solvent used. However, 80 ° C. to 140 ° C. is preferable for easy control of the exchange capacity. If the temperature is too low, the amount of ion exchange groups tends to be insufficient, and if it is too high, there are too many exchange groups or the strength of the ion exchanger tends to be insufficient. Although reaction time does not have a restriction | limiting in particular, In order to advance a uniform reaction, 30 minutes or more are preferable, More preferably, it is 3 to 10 hours. Moreover, a catalyst can be used in order to advance reaction rapidly. As the type of the catalyst, it is preferable to use an alkaline catalyst such as sodium hydroxide, potassium carbonate, sodium carbonate, trimethylamine, triphenylphosphine and the like. The amount added is preferably 1 to 100% by weight based on the compound represented by the above general formula (III) or general formula (IV).

  When the compound represented by the general formula (III) is a hydroxycarboxylic acid ester, the ester moiety may be hydrolyzed and converted to a carboxyl group using an alkaline aqueous solution such as potassium hydroxide or sodium hydroxide. it can. The alkali concentration is preferably 0.1 N or more, more preferably 0.1 to 0.5 N.

  A non-crosslinkable polymerizable monomer having a structure having an ion exchange group represented by the general formula (II) and bonded by an ether bond can also be synthesized. Also in this case, it is preferable to react using the compound represented by the general formula (III) or the general formula (IV). The conditions for introducing the compound represented by the general formula (III) or the general formula (IV) may be the same as the conditions for introducing the polymer particles.

The average particle diameter of the cation exchanger in the present invention is an index of the separation characteristics (theoretical plate number, degree of separation) of the obtained porous polymer particles, and the mixed solution before aqueous suspension polymerization is suspended. It can be easily controlled by adjusting the stirring speed of the agitator. The specific surface area becomes an index of the porosity of the resulting polymer particles, and can be easily controlled by adjusting the type and blending amount of the pore regulator. The average particle diameter of the cation exchanger in the present invention is preferably 1 to 50 μm, more preferably 3 to 30 μm, and still more preferably 5 to 20 μm. Preferably from 1 to 500 ² / g as specific surface area, more preferably 10~450m ² / g, more preferably 30 to 400 m ² / g, particularly preferably 110~300m ² / g. When the average particle size is less than 1 μm, the pressure loss increases when the column is packed, and the column pressure tends to increase. If it exceeds 50 μm, the chromatogram tends to be broad. When the specific surface area is less than 1 m ² / g, the pressure rises when filling, elution of divalent ions tends to be delayed, and when it exceeds 500 m ² / g, the mechanical strength of the filler tends to decrease. .

EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.
Example 1
<Synthesis of polymer particles>
A mixture of 18 g of ethylene glycol dimethacrylate, 21 g of tetramethylol methane trimethacrylate, 165 g of glycidyl methacrylate, 70 g of n-butyl acetate, 130 g of isoamyl alcohol and 0.9 g of azobisisobutyronitrile was added to 2000 g of 0.5% by weight methylcellulose aqueous solution. In addition, suspension polymerization was performed at 90 ° C. for 10 hours.
After the reaction solution was cooled, the produced copolymer was filtered, washed with water and washed with methanol to obtain polymer particles. The resulting polymer particles were classified to an average particle size of 6.5 μm and then dried at 60 ° C. for 15 hours.

<Introduction of exchange groups>
50 g of the above polymer particles were added to a solution prepared by dissolving 100 g of hydroxyphthalic acid dimethyl ester and 50 g of triphenylphosphine in 1250 ml of dimethylformamide, and reacted at 90 ° C. for 8 hours. The reaction product is filtered, washed with dimethylformamide, acetone and ion-exchanged water, then dispersed in 750 ml of 0.5N aqueous potassium hydroxide solution, hydrolyzed at 80 ° C. for 4 hours, and then with 1N nitric acid and ion-exchanged water. Washing gave a weakly acidic cation exchanger.

<Heat treatment>
The ion exchanger was washed with methanol and then heat-treated in a vacuum dryer at a vacuum degree of 755 mmHg and 75 ° C. for 34 hours.

<Filling and evaluation>
The heat-treated ion exchanger (5.0 g) was dispersed in ion-exchanged water and pressure-packed into a 4.6φ × 250 mm PEEK column. The column was mounted on an ion chromatograph (Yokogawa Analytical Systems, product name IC7000) and measured under the following conditions.
Eluent: 2.5 mM oxalic acid Oven temperature: 40 ° C
Flow rate: 1.0 ml / min
Sample: lithium (Li ⁺ ) 0.5 ppm, sodium (Na ⁺ ) 2 ppm, ammonium (NH ₄ ⁺ ) 2 ppm, potassium (K ⁺ ) 5 ppm, magnesium (Mg ²⁺ ) 5 ppm, calcium (Ca ²⁺ ) 5 ppm
Sample injection volume: 50 μl

Table 1 shows the retention time of each ion from the obtained chromatogram. In addition, as a quantified index, the quotient was obtained from the retention time of the obtained NH ₄ ⁺ , Na ⁺ , and Ca ²⁺ ions according to the following formula (I) and is also shown in Table 1. TCa was the retention time of calcium.
TNH ₄ / TNa / TCa (I)
(However, in formula (I), TNH ₄ represents the retention time of NH ₄ ⁺ , TNa represents the retention time of Na ⁺ , and TCa represents the retention time of the slower elution of calcium and magnesium.)
The larger the quotient of TNH ₄ / TNa / TCa, the better the separation of Na ⁺ and NH ₄ ⁺ , indicating that the monovalent cation and divalent cation are not separated. From Table 1, it is excellent in the separation of Na ⁺ and NH ₄ ⁺ , and the divalent cation elutes immediately after the separation of the monovalent cation, and the monovalent cation and the divalent cation are not separated from each other in a short time. A good elution balance that can be separated was shown.

Example 2
<Synthesis of polymer particles>
Polymer particles were synthesized in the same manner as in Example 1.
<Introduction of exchange groups>
In the same manner as in Example 1, an exchange group was introduced into polymer particles to synthesize an ion exchanger.
<Heat treatment>
The ion exchanger was washed with methanol, and then heat-treated in a vacuum dryer at a vacuum degree of 755 mmHg and 75 ° C. for 29 hours.
<Filling and evaluation>
Evaluation was carried out in the same manner as in Example 1, and the retention time of each ion and the quotient of TNH ₄ / TNa / TCa were calculated from the obtained chromatogram and are also shown in Table 1.

Comparative Example 1
<Synthesis of polymer particles>
Polymer particles were synthesized in the same manner as in Example 1.
<Introduction of exchange groups>
In the same manner as in Example 1, an exchange group was introduced into the polymer particles to synthesize an ion exchanger.
<Filling and evaluation>
The ion exchanger synthesized above was evaluated in the same manner as in Example 1 without subjecting it to heat treatment, and the retention time of each ion and the quotient of TNH ₄ / TNa / TCa were calculated from the obtained chromatogram. This is also shown in 1.

Claims (2)

The exchange group of the cation exchanger is represented by the following general formula (II)

(In the general formula (II), n represents an integer of 1 to 5, and R represents a hydrogen atom or an alkyl group.)
For cation analysis ion chromatography, the quotient of the retention time of ammonium / sodium / calcium represented by the following formula (I) is 0.05 or more when oxalic acid with an acid concentration of 2.5 mM is used as the eluent . column.
TNH ₄ / TNa / TCa (I)
(However, in formula (I), TNH ₄ represents the retention time of ammonium, TNa represents the retention time of sodium, and TCa represents the retention time of the slower elution with calcium and magnesium.) The exchange group is represented by the following general formula (II)

(In the general formula (II), n represents an integer of 1 to 5, and R represents a hydrogen atom or an alkyl group.)
A method for producing a column for cation analysis ion chromatography , comprising a step of subjecting the polymer particles having the following structure to a vacuum drying heat treatment at a vacuum degree of 700 mmHg to 760 mmHg and a temperature of 70 ° C to 120 ° C for 5 hours to 150 hours.