Acid-functionalized ion exchange material

Abstract

The present invention relates to an ion exchange material for use as a stationary phase for separating anions, preferably haloacetic acids, in an analytical or preparative separation process. The material comprises: - a polymer support; - an acid group directly bonded to the surface of the polymer support, the acid group being selected from the group consisting of sulfonic acid groups, carboxylic acid groups or combinations thereof; - a polymer layer covalently bonded to the surface of the polymer support, the polymer layer containing an anion exchange group. The amount of the acid group ranges from 0.05 to 1.05 mmol / g, preferably from 0.1 to 0.9 mmol / g, particularly preferably from 0.16 to 0.85 mmol / g of the polymer support. The acid group and the anion exchange group are preferably spatially separated by at least 10 nm, preferably at least 50 nm, most preferably at least 100 nm via the polymer layer. The present invention also relates to a method for producing the ion exchange material, a chromatography column having the ion exchange material, a method for chromatographic separation of an analyte and the use of the ion exchange material.

Description

Technical Field

[0001] The present invention relates to an ion exchange material for use as a stationary phase for separating anions, preferably haloacetic acids, in an analytical or preparative separation process. The present invention further relates to a method for producing such an ion exchange material, a chromatography column filled with the ion exchange material, a method for chromatographically separating an analyte, and the use of the ion exchange material.

Background Art

[0002] Ion exchangers are usually made of particulate materials that carry on their surface charges that enable them to retain ions. Anion exchangers are often based on cationic ammonium compounds, although phosphonium ions and arsonium ions are also known. In the case of purely electrostatic interactions, the retention time is determined by Coulomb's law. Thus, only the charge of the anion should affect the latter's retention time. However, when performing ion chromatography in an aqueous solution, other factors such as the hydration of the anion and the hydration of the exchange groups affect the retention behavior. The polarizability of the ions involved and the weaker secondary interactions between the analyte and the exchange substrate also play a role.

[0003] In International Publication No. 2020208026, by hydrophilizing the polymer core of the particles, the secondary interactions between the analyte and the exchange substrate are reduced. The resulting alcohol groups can be used to bind hydrophilic polymers and anion exchange species. However, the lack of negative charge on these particles results in a long retention time for dichloroacetic acid, which is important for the analysis of drinking water, particularly according to EPA 300.1.

[0004] Another method for reducing the secondary interaction between the analyte and the exchange substrate is described in US Patent Application Publication No. 20050181224. In this method, first the polymer substrate particles are sulfonated, and subsequently a hyperbranched polymer layer is coated onto the negatively charged polymer substrate. The repulsive interaction prevents the diffusion of anions into the hydrophobic core and pores. The particles are highly sulfonated and require many hyperbranching cycles to introduce sufficient ammonium groups to separate anions. In such hyperbranched anion exchangers, the capacity and selectivity cannot be independently varied. The effect of hyperbranching is also described in C. Pohl, C. Saini, J. Chromatogr. A, 1213, (2008), 37 - 44.

[0005] A.S. Uzhel et al., J. Chromatogr. A 1482(2017)57 - 64 describes an anion exchanger having a covalently bonded hyperbranched functional ion - exchange layer containing negatively charged functional groups adjacent to positively charged ammonium groups. The variation in selectivity can be obtained by changing the position and number of carboxylic acid groups in the hyperbranched layer. Good selectivity for weakly retained organic acids and oxyhalides is obtained. However, the anion exchanger has the drawback that since the negative and positive charges are in close proximity, the net charge in the small region where ion exchange occurs is 0, which has an adverse effect on the separation characteristics of specific anions and the column capacity. The capacity and selectivity cannot be adjusted independently. The required pH stability of the separation material is not guaranteed.

[0006] European Patent No. 4019126 describes a method for preparing a solid support for preventing the co - elution of haloacetic acids with specific halogenated oxo and standard anions. Nevertheless, the retention time for standard anions cannot be adjusted by the column material. The disclosed material enables good separation of various anions, but the retention times of some haloacetic acids are quite long. Summary of the Invention Problems to be Solved by the Invention

[0007] Accordingly, at least one object of the present invention is to overcome the drawbacks of the prior art. In particular, one object of the present invention is to provide an ion exchange material that enables good separation of haloacetic acids other than standard anions, is sufficiently stable under alkaline conditions, and provides elution within a reasonable time frame with a shortened retention time. Another object is to provide a method for manufacturing such an ion exchange material. A further object of the present invention is to provide a chromatography column having such an ion exchange material, a method for separating an analyte, and the use of such an ion exchange material. The object of the present invention is also to provide a method for adjusting the retention time of haloacetic acids relative to standard anions in the preparation of the column.

Means for Solving the Problems

[0008] The above object is solved by the subject matter of the independent claims. Specific embodiments are described in the dependent claims.

[0009] A first aspect of the present invention relates to an ion exchange material for use as a stationary phase for separating anions, preferably haloacetic acids, in an analytical or preparative separation process. The ion exchange material comprises - a polymer support, and - an acid group directly bonded to the surface of the polymer support, wherein the acid group is selected from the group consisting of sulfonic acid groups, carboxylic acid groups, or combinations thereof, and - a polymer layer covalently bonded to the surface of the polymer support and containing an anion exchange group. The amount of the acid group ranges from 0.05 to 1.05 mmol / g, preferably from 0.1 to 0.9 mmol / g, particularly preferably from 0.16 to 0.85 mmol / g of the polymer support. The acid group and the anion exchange group are preferably spatially separated by at least 10 nm, preferably at least 50 nm, most preferably at least 100 nm via the polymer layer.

[0010] ​Preferably, the polymer layer has a thickness of 3000 nm or less, preferably 500 nm or less, more preferably 400 or less, and most preferably 300 nm or less.

[0011] The ion-exchange material exhibits good alkali stability and capacity under chromatographic conditions for ion exchange. Furthermore, the acid groups in the above range have been found to enable very good separation of haloacetic acids other than standard anions in particular, and to have a shorter retention time, and thus a reasonable elution time. The number of theoretical plates can be correlated with the amount of carboxylic acid groups, enabling adjustment of the material properties and resulting in sharper peaks of haloacetic acids in the chromatogram as the amount of acid groups increases. Without being bound by theory, it is considered that the acid groups on the surface of the polymer support repel anions and prevent the interaction between the anions and the core of the polymer support. The distance between the anion-exchange group and the acid group is large enough to avoid a net charge of zero in a small region where ion exchange occurs that further improves the separation of the analyte.

[0012] The standard anions referred to in this text are fluoride, chloride, nitrite, bromide, and nitrate.

[0013] The separation of haloacetic acids is becoming increasingly important after the separation of standard anions due to the increasing number of future standards (Chinese GBT 5750.10-2020) and existing standards (US EPA 557). These standards are used to identify low-concentration disinfection by-products. Low concentrations require small peaks and short retention times for sufficiently good identification.

[0014] The amount of negative charge on the ion-exchange material was determined by a titration method described in more detail below.

[0015] Preferably, the polymer layer is bonded to the polymer support via an oxygen bond or a nitrogen bond.

[0016] The polymer support can exist as particles, as a gel, or as a membrane. Particles are preferred.

[0017] The polymer layer is preferably directly bonded to the polymer support, i.e., not bonded via an acid group.

[0018] "Spatially separated" refers to separation through bonds and space. The distance between the acid group and the anion exchange group was calculated based on the bond length between these groups.

[0019] The polymer support is - at least partially derived from an aromatic hydrocarbon compound having at least two vinyl substituents or allyl substituents, preferably at least partially derived from a divinylbenzene monomer, and - partially derived from a monomer selected from the group consisting of ethylvinylbenzene, vinyl acetate, styrene, and any combination thereof.

[0020] The relative amount of the aromatic hydrocarbon compound having at least two vinyl substituents or allyl substituents, preferably the relative amount of the monomer derived from divinylbenzene, is preferably at least 50% by weight.

[0021] The polymer support can be derived only from styrene and divinylbenzene (DVB: divinylbenzene) monomers.

[0022] For example, the polymer can be a polystyrene-divinylbenzyl (PS / DVB: polystyrene-divinylbenzyl) polymer, most preferably PS / DVB resulting from 55% divinylbenzene in ethylvinylbenzene.

[0023] Polystyrene-divinylbenzene polymers are readily available as support materials by different synthetic methods known in the art.

[0024] The polymer support preferably comprises open pores having an average pore diameter of up to 60 nm. Even more preferably, the pores are microporous and / or mesoporous as defined by the IUPAC definition and measurable by nitrogen adsorption in the BJH model, as further described below.

[0025] Advantageously, the polymer layer is - derived from the reaction of a polymer support, preferably a hydrophilic polymer support, with an oligoamine or polyamine, or - derived from the reaction of a polymer support, preferably a hydrophilic polymer support, with at least one polyfunctional compound comprising at least a first functional group reactive with an amine and / or hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or hydroxy group.

[0026] For example, the oligoamine, polyamine or at least one polyfunctional compound can be covalently linked to the polymer support via aldehyde, ketone or hydroxy groups on the polymer support, as described in more detail below.

[0027] Alternatively, the polymer layer is - derived from the reaction of a polymer support, preferably a hydrophilic polymer support, with at least one polyfunctional compound comprising at least a first functional group reactive with an amine and / or hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or hydroxy group, followed by - a reaction with an oligoamine or polyamine.

[0028] The addition of the polymer layer or the composition of the polymer layer allows for further adjustment of the selectivity of the ion exchange material.

[0029] The polymer layer can be crosslinked with at least one polyfunctional compound. Crosslinking of the polymer layer allows for further improvement of the material properties, particularly the separation of haloacetic acids, more specifically the separation of monochloroacetic acid and monobromoacetic acid.

[0030] Preferably, at least one polyfunctional compound is - an epoxide, especially 1,4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, poly(ethylene glycol) diglycidyl ether, resorcinol diglycidyl ether, glycerol diglycidyl ether, glycidol, - an organic halogen-containing compound, especially epichlorohydrin, epibromohydrin, 1,1'-oxybis[2-(2-chloroethoxy)ethane], 1,2-bis(2-chloroethoxy)ethane, bis(2-chloroethyl) ether, 1-chloro-3-iodopropane, 1,4-dibromobutane, 1,3-dibromopropane, - an aldehyde, especially selected from glutaraldehyde.

[0031] The advantage of at least one polyfunctional compound is the various modifications of the materials it provides. The selectivity can be adjusted by adjusting the hydrophilicity or hydrophobicity. In particular, the hydrophilicity of 1,4-butanediol diglycidyl ether (BDGE) is advantageous for the selectivity of haloacetic acids.

[0032] The anion exchange group is preferably a quaternary ammonium group, most preferably a quaternary ammonium group resulting from the reaction with glycidyltrimethylammonium chloride, glycidylmethyldiethanolammonium chloride, and glycidyltriethylammonium chloride, or a tertiary amine, for example, N-methyl-2-pyrrolidone, N-methylmorpholine, N-methylpyrrolidine, N,N-dimethylethanolamine, N-methyldiethanolamine, N-methylpiperidine, N-ethylpiperidine, trimethylamine, triethylamine.

[0033] It is also possible to use a charged phosphine group as the anion exchange group. Preferably, the oligoamine or polyamine is selected from the group consisting of polyallylamine, linear or branched polyethyleneimine (PEI), and poly(2-methylaziridine), and is preferably branched PEI.

[0034] Preferably, the ion exchange material - a polymer support, and - an acid group directly bonded to the surface of the polymer support, wherein the acid group is selected from the group consisting of a sulfonic acid group, a carboxylic acid group, or a combination thereof, and - a polymer layer covalently bonded to the surface of the polymer support.

[0035] The polymer layer (i) a polymer layer derived from an oligoamine or polyamine and bonded to the support via reductive amination of the polymer support, or (ii) or a polymer layer derived from the reaction of at least one polyfunctional compound containing at least a first functional group reactive with an amine and / or hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or hydroxy group.

[0036] The polymer layer (i) or the polymer layer (ii) can contain an anion exchange group. Preferably, the amount of the acid group of the material having the polymer layer (i) is in the range of 0.41 to 1.05 mmol / g, preferably 0.65 to 1.05 mmol / g, particularly preferably 0.85 to 1.05 mmol / g of the polymer support. Preferably, the amount of the acid group of the material having the polymer layer (ii) is in the range of 0.05 to 0.19 mmol / g, preferably 0.05 to 0.16 mmol / g, particularly preferably 0.05 to 0.10 mmol / g of the polymer support. The acid group and the anion exchange group are at least 10 nm, preferably at least 50 nm, most preferably at least 100 nm, and preferably spatially separated for (i) and (ii) via the polymer layer.

[0037] A smaller amount of acid groups still provides very good separation at a reasonable elution time of haloacetic acids compared to the standard anion and also provides sufficient stability against alkaline conditions. Surprisingly, for carboxylic acid groups above 0.25 mmol / g, the material was found not to be permanently stable under strong alkaline conditions and, for example, in the case of polymer (ii), when containing oxygen bonds, it began to lose its capacity over time. However, a larger amount of acid groups results in higher alkaline stability and enables a faster elution time.

[0038] In the case of a larger amount of carboxylic acid groups above 0.41 mmol / g, the polymer layer having nitrogen bonds shows particularly good alkaline stability, for example in the case of polymer (i).

[0039] Thus, the long-term persistent ion exchange material provides good separation characteristics of haloacetic acids compared to the standard anion under strong alkaline conditions.

[0040] Preferably, the polymer layer (i) is bonded to the polymer support via a nitrogen bond, and the polymer layer (ii) is bonded to the polymer support via an oxygen bond.

[0041] Advantageously, the polymer layer is derived from -(i) the reaction of a polymer support, preferably a hydrophilic polymer support, with an oligoamine or polyamine, or -(ii) the reaction of a polymer support, preferably a hydrophilic polymer support, with at least a first functional group that is less reactive with amines and / or hydroxy groups, preferably an epoxy group, and at least one polyfunctional compound containing at least a second functional group that is less reactive with amines and / or hydroxy groups.

[0042] For example, oligoamines and polyamines can be covalently bonded to the polymer via an aldehyde group or a ketone group, and the at least one polyfunctional compound may be covalently linked to the polymer support via a hydroxy group on the polymer support.

[0043] The polymer layer (i) or the polymer layer (ii) can be crosslinked with at least one polyfunctional compound as described above.

[0044] The anionic exchange group is preferably a quaternary ammonium group, and most preferably, in the case of the polymer layer i), a quaternary ammonium group resulting from the reaction with glycidyltrimethylammonium chloride, glycidylmethyldiethanolammonium chloride, and glycidyltriethylammonium chloride. In the case of the polymer layer ii), the anionic exchange group is preferably a tertiary amine, for example, a quaternary ammonium group resulting from the reaction with N-methyl-2-pyrrolidone, N-methylmorpholine, N-methylpyrrolidine, N,N-dimethylethanolamine, N-methyldiethanolamine, N-methylpiperidine, N-ethylpiperidine, trimethylamine, and triethylamine.

[0045] Another aspect of the present invention relates to a method for producing an ion exchange material having an amount of acid groups in the range of 0.05 to 1.05 mmol / g, preferably 0.1 to 0.9 mmol / g, particularly preferably 0.16 to 0.85 mmol / g of a polymer support for use as a stationary phase in an analytical or preparative separation process, wherein each acid group is spatially separated from an anionic exchange group by at least 10 nm, preferably at least 50 nm, and most preferably at least 100 nm. The ion exchange material is preferably an ion exchange material as described above. The method comprises a) providing a polymer support; b) oxidizing the polymer support in the presence of an oxidizing reagent, preferably a peracid; c) partially reducing the polymer support obtained in step b) with a reducing agent to obtain a hydrophilic polymer support; d) reacting the product of step c) with at least one polymer or polymer precursor to obtain a polymer layer on the polymer support; e) introducing an anionic exchange group into the polymer layer.

[0046] Steps c) and d) are carried out simultaneously or sequentially, in total or in part. Preferably, the polymer layer has a thickness of 3000 nm or less, preferably 500 nm or less, more preferably 400 or less, and most preferably 300 nm or less.

[0047] Surprisingly, it has been found that the partial reduction in step c) correlates with the amount of acid groups formed on the polymer support, thus enabling the adjustment of the properties of the polymer support as an ion exchange material.

[0048] The resulting ion exchange material exhibits good stability and high capacity. The amount of acid groups enables very good separation of haloacetic acids adjacent to the standard anions with a shorter retention time of the haloacetic acids. The peaks of the haloacetic acids are sharper in the chromatogram and the number of theoretical plates increases. The distance between the anion exchange groups and the acid groups is large enough to avoid a zero net charge in the small region where ion exchange occurs.

[0049] The polymer support obtained after step b) and / or c) is an essentially hydrophilic polymer support. "Essentially hydrophilic" means that the polymer support forms a suspension in water. 1 g of the hydrophilic polymer support was suspended in 20 mL of water using a Phoenix RA-VA Vortex mixer and the solution was shaken for 30 seconds. The particles of the polymer support remained suspended for at least 15 minutes if they were sufficiently hydrophilic.

[0050] Step b) can result in the formation of carboxylic acid groups (COOH), and step c) can result in the formation of hydroxy groups (OH) on the polymer support, together with the remaining carboxylic acid groups in part. Most preferably, the hydroxy groups of the polymer support react with the polymer or polymer precursor in step d) to provide an oxygen bond between the polymer support and the polymer layer.

[0051] The oxidizing reagent for step b), preferably a peracid, can be generated in situ. The polymer precursor can be any molecule that enables the formation of a polymer layer by a plurality of reactions with itself or other molecules, for example, a polyfunctional compound as a monomer, a poly- or oligoamine as further described below.

[0052] After step b) or step c), additional treatment can be carried out in the presence of sulfuric acid. In either case, the step is carried out before step d). This step enables the introduction of sulfonic acid groups onto the polymer support and can provide a polymer support in which carboxylic acid groups and sulfonic acid groups are directly bonded. Most preferably, the step is carried out in the presence of acetic acid as a solvent.

[0053] Sulfonic acid groups in combination with carboxylic acid groups further push haloacetic acids to a faster retention time compared to carboxylic acids alone in the same amount. This is most likely because the pKa of sulfonic acid groups (SO3H) is lower than that of carboxylic acid groups (COOH). a is the lowest.

[0054] A particular advantage of this method compared to a polymer support having only sulfonic acid groups is that the polymer layer may still be covalently bonded to the polymer support. For example, at a ratio of 0.15 mmol / g sulfonic acid groups to 0.23 mmol / g carboxylic acid groups, only a small amount of sulfonic acid groups are added and combined with carboxylic acid groups, so the resolution of the injection peak to fluoride (IP / F) is still very good.

[0055] The amount of peracid in step b) is preferably generated in the presence of an acid and hydrogen peroxide, and the ratio (mol / mol) of the acid to H2O2 is in the range of 1.0:0.12 to 1.0:0.72, preferably 1.0:0.14 to 1.0:0.52, and most preferably 1.0:0.16 to 1.0:0.44.

[0056] Most preferably, 35% hydrogen peroxide is used and added in the amount added to the above ratio. The reducing agent can be selected from the group consisting of lithium aluminum hydride, sodium borohydride, sodium triacetoxyborohydride, and sodium cyanoborohydride.

[0057] The amount of the reducing agent in step c) can be in the range of 0.03 g to 1.0 g, preferably 0.05 g to 0.8 g, and most preferably 0.1 g to 0.5 g per 1.0 g of the polymer support obtained in step b), based on the dry weight of the polymer support.

[0058] "Dry weight" means that the polymer support or polymer is present at 98% or more, that is, has a moisture content of 2% or less. The moisture content was analyzed using a Sartorius micro moisture analyzer MA 35.

[0059] The amount of the reducing agent enables partial reduction of the carboxylic acid groups present, thus enabling adjustment of their amounts, thereby enabling selection and adjustment of the number of theoretical plates.

[0060] The polymer support in step a) is preferably - at least partially derived from an aromatic hydrocarbon compound having at least two vinyl substituents or allyl substituents, preferably at least partially derived from a divinylbenzene monomer, and - partially derived from a monomer selected from the group consisting of ethylvinylbenzene, vinyl acetate, styrene, and any combination thereof.

[0061] The relative amount of the aromatic hydrocarbon compound having at least two vinyl substituents or allyl substituents, preferably the relative amount of the divinylbenzene-derived monomer, is preferably at least 50% by weight.

[0062] For example, the polymer can be a polystyrene-divinylbenzyl (PS / DVB) polymer, most preferably a PS / DVB resulting from 55% divinylbenzene in ethyl vinyl benzene. Copolymers consisting only of polystyrene and divinylbenzene components are also contemplated.

[0063] The polymer support provided in step a) is preferably open porous with an average pore size of at most 60 nm. Even more preferably, the pores are microporous and / or mesoporous as measurable by nitrogen adsorption in the BJH model, according to the IUPAC definition, as further explained below.

[0064] Step d) - reacting the support material obtained in step b) with an oligoamine or polyamine, preferably in the presence of a reducing agent, or - reacting the support material obtained in step c) with at least one polyfunctional compound as a polymer precursor comprising at least a first functional group reactive with an amine and / or hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or hydroxy group, preferably an epoxy group.

[0065] In the first case, steps c) and d) are preferably carried out simultaneously. On the other hand, in the second case, steps c) and d) are preferably carried out sequentially.

[0066] Alternatively, step d) - reacting the support material obtained in step c) with at least one polyfunctional compound as a polymer precursor material comprising at least a first functional group reactive with an amine and / or hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or hydroxy group, preferably an epoxy group, followed by - reacting with an oligoamine or polyamine.

[0067] The amount of at least one polymer or polymer precursor, in particular an oligoamine, polyamine or at least one polyfunctional compound, in step d) can range from 0.1 g to 10.0 g, preferably from 0.5 g to 8.0 g, most preferably from 1.5 g to 7.0 g, per gram of the polymer support obtained in step c), based on the dry weight of the polymer support.

[0068] Furthermore, after step e), preferably a crosslinking step f): treating the reaction product resulting from step e) with at least one polyfunctional compound, follows.

[0069] Advantageously, the polyfunctional compound is - an epoxide, in particular 1,4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, poly(ethylene glycol) diglycidyl ether, resorcinol diglycidyl ether, glycerol diglycidyl ether, glycidol, - an organic halogen-containing compound, in particular epichlorohydrin, epibromohydrin, 1,1'-oxybis[2-(2-chloroethoxy)ethane], 1,2-bis(2-chloroethoxy)ethane, bis(2-chloroethyl) ether, 1-chloro-3-iodopropane, 1,4-dibromobutane, 1,3-dibromopropane, - an aldehyde, in particular glutaraldehyde.

[0070] In step e), the polymer support of step d) preferably reacts with a quaternary amine selected from the group consisting of glycidyltrimethylammonium chloride, glycidylmethyldiethanolammonium chloride, and glycidyltriethylammonium chloride, or preferably reacts with a tertiary amine selected from the group consisting of N-methyl-2-pyrrolidone, N-methylmorpholine, N-methylpyrrolidine, N,N-dimethylethanolamine, N-methyldiethanolamine, N-methylpiperidine, N-ethylpiperidine, trimethylamine, and triethylamine.

[0071] The oligoamine or polyamine can be selected from the group consisting of polyallylamine, linear or branched polyethyleneimine (PEI), and poly(2-methylaziridine), and is preferably branched PEI.

[0072] In a subsequent step of step e) or f), a hydrolysis step, particularly a basic hydrolysis step, can be carried out to remove the ester that may be formed and hydrolyze the ester bond back to a carboxylic acid group.

[0073] Preferably, the method includes producing an ion exchange material having an amount of acid group (i) in the range of 0.41 to 1.05 mmol / g of the polymer support, preferably 0.65 to 1.05 mmol / g, particularly preferably 0.85 to 1.05 mmol / g, or an amount of acid group (ii) in the range of 0.05 to 0.19 mmol / g of the polymer support, preferably 0.05 to 0.16 mmol / g, particularly preferably 0.05 to 0.10 mmol / g. Each acid group is spatially separated from the anion exchange group by at least 10 nm, preferably at least 50 nm, and most preferably at least 100 nm for use as a stationary phase in an analytical or preparative separation process. The ion exchange material is preferably an ion exchange material as described above. The method a) providing a polymer support; b) oxidizing the polymer support in the presence of an oxidizing reagent, preferably a peracid; c) partially reducing the polymer support obtained in step b) with a reducing agent to obtain a hydrophilic polymer support; d) reacting the product of step c) with (i) at least one oligoamine or polyamine for obtaining a polymer layer on the polymer support, or (ii) at least one polyfunctional compound containing a first functional group reactive with at least an amine and / or a hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or a hydroxy group, and reacting it with the polymer support to obtain a polymer layer; e) introducing an anion exchange group into the polymer layer obtained in step d)(i) or the polymer layer obtained in step d)(ii).

[0074] Steps c) and d)(i) are preferably carried out simultaneously, and steps c) and d)(ii) are preferably carried out continuously, either wholly or partly.

[0075] This material is particularly stable under alkaline conditions and has very good separation characteristics for haloacetic acids with respect to standard anions as described above.

[0076] Most preferably, the hydroxy groups of the polymer support react with the polymer in step d)(ii), resulting in an oxygen bond between the polymer support and the polymer layer. The nitrogen-containing bond is preferably the result of the reaction between the polymer support and the oligoamine or polyamine in step d)(i).

[0077] Step d) comprises -(i) reacting the support material obtained in step b) with an oligoamine or polyamine, preferably in the presence of a reducing agent, or -(ii) reacting the support material obtained in step c) with at least one polyfunctional compound as a polymer precursor containing at least a first functional group reactive with an amine and / or hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or hydroxy group, preferably an epoxy group.

[0078] In the first case (i), steps c) and d) are preferably carried out simultaneously. On the other hand, in the second case (ii), it is preferred that steps c) and d) are carried out consecutively.

[0079] In step e), the polymer support of step d)(i) is reacted with a quaternary amine preferably selected from the group consisting of glycidyltrimethylammonium chloride, glycidylmethyldiethanolammonium chloride, and glycidyltriethylammonium chloride. The polymer support of step d)ii) is reacted with a tertiary amine preferably selected from the group consisting of N-methyl-2-pyrrolidone, N-methylmorpholine, N-methylpyrrolidine, N,N-dimethylethanolamine, N-methyldiethanolamine, N-methylpiperidine, N-ethylpiperidine, trimethylamine, and triethylamine.

[0080] Another aspect of the present invention relates to an ion exchange material for use as a stationary phase in an analytical or preparative separation process, particularly a chromatography process, obtainable by the method described above.

[0081] A further aspect of the present invention relates to a chromatography column filled with the ion exchange material described above, particularly an ion exchange chromatography column.

[0082] Surprisingly, such columns have been found to enable the measurement of haloacetic acids for the improved separation of these compounds in a shorter time.

[0083] Furthermore, another aspect of the present invention relates to a method for chromatographically separating an analyte, particularly an anion, more preferably a haloacetic acid, most preferably monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), and dibromoacetic acid (DBA). This method includes the step of contacting a solution containing the analyte with the ion exchange material as described above, particularly the solution passes through a chromatography column as described above.

[0084] It may also be possible to separate the following compounds: trichloroacetic acid, tribromoacetic acid, bromo-dichloroacetic acid, chloro-dibromoacetic acid and dichloropropionic acid.

[0085] Most preferably, the chromatographic separation method can be carried out in accordance with EPA 557.

[0086] Another aspect of the present invention relates to the use of an ion exchange material obtained by the method as described above and / or as described above for the analysis or preparative separation of analytes, preferably anions, more preferably haloacetic acids, most preferably for the separation of monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA) and dibromoacetic acid (DBA).

[0087] A further aspect of the present invention relates to a method for preparing a chromatographic column using an ion exchange material, preferably as described above. This method includes the step of adjusting the retention time of haloacetic acids with respect to standard anions, particularly the standard anions described herein. The retention time is adjusted by acid groups directly bonded to the surface of the polymer support, and the acid groups are selected from the group consisting of sulfonic acid groups, carboxylic acid groups or combinations thereof, and the amount of acid groups is in the range of 0.41 to 1.05 mmol / g, preferably 0.65 to 1.05 mmol / g, particularly preferably 0.85 to 1.05 mmol / g of the polymer support, or in the range of 0.05 to 0.19 mmol / g, preferably 0.05 to 0.16 mmol / g, particularly preferably 0.05 to 0.10 mmol / g of the polymer support.

[0088] The polymer support is preferably the aforementioned polymer support. The polymer support can include a polyamine or a polymer layer as described above.

[0089] The column can be used for the separation of haloacetic acids against standard anions. The present invention will be described in more detail with reference to the figures and examples. The figures and examples should not be understood as limiting.

Brief Description of the Drawings

[0090]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0091] Example Determination of Starting Material and Pore Diameter The starting material for the following examples is PS / DVB particles. The average pore radius of the PS / DVB particles provided in step a) was determined by nitrogen adsorption in the BJH (Barret, Joyner, Halenda) model. The specific surface area was determined by nitrogen adsorption in the BET model (Brunauer, Emmett, Teller). For both analyses, a sample of 0.10945 g of the PS / DVB polymer support was used. The density of the sample material was 1.105 g / cc. The measurements were carried out on an Autosorb iQ S / N: 14713051301 apparatus with a 9 mm cell. The bath temperature was 77.35 K. The final degassing temperature was 60 °C. The evaluation of the measurements was performed with Quantachrome AsiQwin version 3.01. The measurements were carried out twice, once with an immersion time of 80 minutes and once with an immersion time of 40 minutes. The gas evolution rates were 1.0 °C / min and 20.0 °C / min, respectively. The average pore radius obtained from the BJH method based on the pore volume was 5.1060 nm. The specific surface area calculated by the multi-point BET plot was 540.0 m 2 / g.

[0092] Oxidation (Examples 1.1 to 1.5) The following examples show different examples of the oxidation step b). However, the reaction conditions can be varied within the scope of the present invention, and the possible reaction conditions are summarized herein. The solvent can be either acetic acid or formic acid, with acetic acid being preferred. The reaction temperature can vary between 15 and 80 °C, with 80 °C being the preferred temperature. The temperature gradient can be 30 to 120 °C / h, preferably 45 °C / h. Thus, the reaction is preferably carried out in the presence of hydrogen peroxide. The ratio (mol / mol) of the acid to hydrogen peroxide can range from 1.0:0.12 to 1.0:0.72, preferably from 1.0:0.14 to 1.0:0.52, and most preferably from 1.0:0.16 to 1.0:0.44. The reaction time can vary between 18 and 80 hours, with 72 hours (h) being most preferred.

[0093] Example 1.1 10.1 g of PS / DVB (55% DVB in EVB) particles were suspended in 67 g of acetic acid, and 19 g of hydrogen peroxide (35%) was added. The mixture was heated to 80 °C with a temperature gradient of 45 °C / h. The reaction mixture was stirred for 72 hours, cooled, and filtered. The filter cake was washed with water until pH neutral. The filter cake was dried in vacuo at 60 °C for at least 16 hours.

[0094] Example 1.2 10.5 g of PS / DVB (55% DVB in EVB) particles were suspended in 65 g of acetic acid, and 27 g of hydrogen peroxide (35%) was added. The mixture was heated to 80 °C with a temperature gradient of 45 °C / h. The reaction mixture was stirred for 72 hours, cooled, and filtered. The filter cake was washed with water until pH neutral. The filter cake was dried in vacuo at 60 °C for at least 16 hours.

[0095] Example 1.3 10.5 g of PS / DVB (55% DVB in EVB) particles were suspended in 65 g of acetic acid, and 24 g of hydrogen peroxide (35%) was added. The mixture was heated to 80 °C with a temperature gradient of 45 °C / h. The reaction mixture was stirred for 72 hours, cooled, and filtered. The filter cake was washed with water until pH neutral. The filter cake was dried in vacuo at 60 °C for at least 16 hours.

[0096] Example 1.4 10.1 g of PS / DVB (55% DVB in EVB) particles were suspended in 64 g of acetic acid, and 28 g of hydrogen peroxide (35%) was added. The mixture was heated to 80 °C with a temperature gradient of 45 °C / h. The reaction mixture was stirred for 72 hours, cooled, and filtered. The filter cake was washed with water until pH neutral. The filter cake was dried in vacuo at 60 °C for at least 16 hours.

[0097] Example 1.5 9.8 g of PS / DVB (55% DVB in EVB) particles were suspended in 67 g of acetic acid and 18 g of hydrogen peroxide (35%) was added. The mixture was heated to 80 °C with a temperature gradient of 45 °C / h. The reaction mixture was stirred for 24 h, cooled and filtered. The filter cake was washed with water to pH neutral. The filter cake was dried in vacuo at 60 °C for at least 16 h.

[0098] Reduction (Examples 2.1 - 2.12) The following examples show different examples of the partial reduction of step c). However, the reaction conditions can be varied within the scope of the invention and the possible reaction conditions are summarized herein. The reaction temperature can be from 20 to 110 °C. The amount of reducing agent can be from 0.03 g to 1.0 g, preferably from 0.05 g to 0.8 g, most preferably from 0.1 g to 0.5 g per gram of dry polymer support. The reaction time can vary between 3 and 30 h. In the case of lithium aluminum hydride (LiAlH4) as reducing agent (Examples 2.1 - 2.9 and 2.12), the solvent is preferably cyclopentyl methyl ether, tetrahydrofuran, toluene and all solvents are of dry grade (<0.1% water). In the case of sodium borohydride (NaBH4) or sodium triacetoxyborohydride as reducing agent (Examples 2.10 - 2.11), the solvent can be water, ethanol, methanol, tetrahydrofuran.

[0099] Example 2.1 10 g of the dry product of Example 1.1 was suspended in 40 mL of cyclopentyl methyl ether. The mixture was heated to 70 °C and then 2.7 g of lithium aluminum hydride was added. The mixture was heated to 110 °C and stirred for 18 h. The temperature was lowered to 50 °C and quenched with acetone, followed by water. The mixture was filtered, the particles were resuspended and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water and ethanol. The particles were dried in vacuo at 60 °C for at least 16 h. This reaction gave a polymer support containing 0.30 mmol / g COOH.

[0100] Example 2.2 The procedure was the same as in Example 2.1, but the product of Example 1.2 was used as the substrate. This reaction yielded a polymer support containing 0.36 mmol / g COOH.

[0101] Example 2.3 10 g of the dried product of Example 1.2 was suspended in 40 mL of cyclopentyl methyl ether. The mixture was heated to 70 °C, and then 2.3 g of lithium aluminum hydride was added. The mixture was heated to 110 °C and stirred for 18 hours. The temperature was lowered to 50 °C and quenched with acetone, followed by water. The mixture was filtered, the particles were resuspended, and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water, and ethanol. The particles were dried in vacuo at 60 °C for at least 16 hours. This reaction yielded a polymer support containing 0.41 mmol / g COOH.

[0102] Example 2.4 10 g of the dried product of Example 1.2 was suspended in 40 mL of cyclopentyl methyl ether. The mixture was heated to 70 °C, and then 3.3 g of lithium aluminum hydride was added. The mixture was heated to 95 °C and stirred for 24 hours. The temperature was lowered to 50 °C and quenched with acetone, followed by water. The mixture was filtered, the particles were resuspended, and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water, and ethanol. The particles were dried in vacuo at 60 °C for at least 16 hours. This reaction yielded a polymer support containing 0.17 mmol / g COOH.

[0103] Example 2.5 The procedure was the same as in Example 2.4, but the product of Example 1.3 was used as the substrate. This reaction yielded a polymer support containing 0.15 mmol / g COOH.

[0104] Example 2.6 10 g of the reaction product of Example 1.4 was suspended in 40 mL of cyclopentyl methyl ether. The mixture was heated to 50 °C, and then 1.8 g of lithium aluminum hydride was added. The mixture was heated to 95 °C and stirred for 24 hours. The temperature was lowered to 50 °C and quenched with acetone, followed by water. The mixture was filtered, the particles were resuspended, and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water, and ethanol. The particles were dried in vacuo at 60 °C for at least 16 hours. This reaction gave a polymer support containing 0.32 mmol / g of COOH.

[0105] Example 2.7 10 g of the reaction product of Example 1.4 was suspended in 40 mL of cyclopentyl methyl ether. The mixture was heated to 50 °C, and then 2.3 g of lithium aluminum hydride was added. The mixture was heated to 95 °C and stirred for 24 hours. The temperature was lowered to 50 °C and quenched with acetone, followed by water. The mixture was filtered, the particles were resuspended, and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water, and ethanol. The particles were dried in vacuo at 60 °C for at least 16 hours. This reaction gave a polymer support containing 0.27 mmol / g of COOH.

[0106] Example 2.8 10 g of the reaction product of Example 1.4 was suspended in 40 mL of cyclopentyl methyl ether. The mixture was heated to 50 °C, and then 3.8 g of lithium aluminum hydride was added. The mixture was heated to 95 °C and stirred for 24 hours. The temperature was lowered to 50 °C and quenched with acetone, followed by water. The mixture was filtered, the particles were resuspended, and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water, and ethanol. The particles were dried in vacuo at 60 °C for at least 16 hours. This reaction gave a polymer support containing 0.19 mmol / g of COOH.

[0107] Example 2.9 10 g of the reaction product of Example 1.4 was suspended in 40 mL of cyclopentyl methyl ether. The mixture was heated to 50 °C, and then 4.3 g of lithium aluminum hydride was added. The mixture was heated to 95 °C and stirred for 24 hours. The temperature was lowered to 50 °C and quenched with acetone, followed by water. The mixture was filtered, the particles were resuspended, and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water, and ethanol. The particles were dried in vacuo at 60 °C for at least 16 hours. The reaction gave a polymer support with 0.16 mmol / g COOH.

[0108] Example 2.10 5 g of the reaction product of Example 1.4 was suspended in 25 mL of water and 3 mL of sodium hydroxide (aqueous solution, 30%). 5 g of sodium borohydride was added to the suspension. The mixture was heated to 80 °C and stirred for 17 hours. The reaction mixture was cooled to room temperature and 100 mL of sulfuric acid (aqueous solution, 10%) was added. The mixture was filtered, washed with water until neutral pH, and then with acetone. The particles were dried in vacuo at 60 °C for at least 16 hours. The reaction gave a polymer support with 1.02 mmol / g COOH.

[0109] Example 2.11 5 g of the reaction product of Example 1.1 was suspended in 40 mL of ethanol. 1.35 g of polyethyleneimine (M n = 10,000 Da) was added, followed by 0.25 mL of acetic acid. After stirring the mixture for 1 hour, 1.9 g of sodium triacetoxyborohydride was added. The reaction mixture was stirred for 19 hours. The mixture was filtered, and the filter cake was washed with water until neutral pH. The particles were dried in vacuo at 60 °C for at least 16 hours. The reaction gave a polymer support containing 0.82 mmol / g COOH.

[0110] Example 2.12 The procedure was the same as in Example 2.1 except that the reaction product of 1.5 was used. The reaction gave 0.1 mmol / g COOH.

[0111] Introduction of sulfonic acid groups (Examples 3.1 and 3.2) The following examples show the introduction of sulfonic acid groups after step b or c). The reaction can be carried out in any of acetic acid, dichloroethane or dichloromethane. Acetic acid is preferred.

[0112] Example 3.1 17 g of the particles of Example 1.3 were reduced as described in Example 2.1, and these particles had a carboxylic acid content of 0.23 mmol / g. The particles were suspended in 100 mL of acetic acid and 20 mL of sulfuric acid and reacted for 32 seconds. The reaction mixture was then diluted with 50 mL of hydrochloric acid and filtered. The filter cake was washed with water, ethanol, sodium hydroxide (aqueous solution, 2M), water, hydrochloric acid (aqueous solution, 1M) and water until neutral pH. The particles were dried in vacuo at 60 °C for 16 hours to obtain a product containing 0.38 mmol / g of both carboxylic acid groups and sulfate groups as negative charges.

[0113] Example 3.2 20 g of the particles of Example 1.3 were reduced by suspending the particles in 80 mL of cyclopentyl methyl ether. The mixture was heated to 70 °C, and then 5.4 g of lithium aluminum hydride was added. The mixture was heated to 110 °C and stirred for 18 hours. The temperature was lowered to 50 °C and quenched with acetone and then water. The mixture was filtered, the particles were resuspended and washed with the following solutions: acetone, tartaric acid / acetic acid solution (2.5 / 1 wt%, 47% aqueous solution), water and ethanol. The particles were dried in vacuo at 60 °C for at least 16 hours. The particles were suspended in 4 mL of sulfuric acid and reacted for 30 minutes. The reaction mixture was then diluted with 45 mL of hydrochloric acid and filtered. The filter cake was washed with water, sodium hydroxide (aqueous solution, 1M), water, hydrochloric acid (aqueous solution, 1M), water until neutral pH, and ethanol. The particles were dried in vacuo at 60 °C for 16 hours to obtain a product containing 0.52 mmol / g of both carboxylic acid groups and sulfate groups as negative charges.

[0114] Introduction of a polymer layer having an anion exchange group (Examples 4.1 to 4.4, 5.1 to 5.7 and 6.1) The following examples describe specific embodiments for introducing a polymer layer onto a polymer support.

[0115] The following reactions include examples of forming a polymer layer from BDGE and an amine, BDGE and PEI, or PEI. The reaction conditions can be adjusted as follows and are not limited to the conditions provided in the examples: The amount of polymer or polymer precursor can be from 0.1 g to 10 g, preferably from 0.5 g to 8.0 g, and most preferably from 1.5 g to 7.0 g per 1 g of the dry polymer support.

[0116] The reaction is preferably carried out in ethanol, water, dimethyl sulfoxide, or a combination thereof. The reaction temperature is selected between 20 and 80 °C, with 40 °C being preferred for BDGE and 60 °C being preferred for PEI. The reaction time is selected between 2 and 24 hours. Specific to the introduction of BDGE is the addition of a base, preferably sodium hydroxide, and the repetition of 0 to 20 reaction cycles.

[0117] The reaction conditions for introducing anion exchange groups can be summarized as follows: In the examples listed below, a quaternary ammonium is added to PEI. Or a tertiary amine is added to BDGE. As quaternary amine introducing species, glycidyltrimethylammonium chloride, glycidylmethyldiethanolammonium chloride, and glycidyltriethylammonium chloride can be used. As tertiary amines, N-methyl-2-pyrrolidone, N-methylmorpholine, N-methylpyrrolidine, N,N-dimethylethanolamine, N-methyldiethanolamine, N-methylpiperidine, N-ethylpiperidine, trimethylamine, and triethylamine can be used. The reaction is carried out in water or dimethyl sulfoxide at a reaction temperature of 20 to 80 °C and a reaction time of 2 to 24 hours.

[0118] The additional cross-linking step f) can be carried out in water or dimethyl sulfoxide at a temperature of 30 to 80 °C, preferably 60 °C, and a reaction time of 1 to 24 hours, preferably 3 hours.

[0119] In the following examples, the elimination step can be carried out under basic conditions, preferably in an aqueous solution of sodium hydroxide (0.5 - 7.5 M), sodium carbonate (0.5 - 5.0 M) and potassium hydroxide (0.5 - 7.5 M), at a temperature of 20 - 100 °C and a reaction time of 2 hours to 2 months (1460 hours).

[0120] BDGE-PEI-ammonium ion-crosslinking Example 4.1 10 g of the reaction product of Example 2.1 was suspended in 31 mL of dimethyl sulfoxide and 25 mL of 1,4-butanediol diglycidyl ether. The mixture was heated to 40 °C. 23 mL of water and 2.3 mL of NaOH (aqueous solution, 33%) were added to the reaction mixture and stirred for 5 hours. The mixture was filtered and the filter cake was washed with water until the pH was neutral. The dried particles were suspended in 30 mL of a 1:4 v / v ethanol / water mixture. 4 g of polyethyleneimine (M n = 600 Da) was added and the mixture was stirred at 60 °C for 16 hours. The mixture was filtered and the filter cake was washed with water until the pH was neutral. The filter cake was dried in vacuo to obtain particles with a thick polymer layer. The particles were suspended in 100 mL of water. 14 g of glycidyltrimethylammonium chloride was added and the mixture was stirred at 60 °C for 4 hours. The mixture was filtered and the filter cake was washed with water until the pH was neutral. The dried particles were suspended in 200 mL of water and 18.4 mL of 1,4-butanediol diglycidyl ether was added. The mixture was heated to 60 °C and stirred for 2.5 hours. The reaction mixture was filtered and the filter cake was washed with water until the pH was neutral. The cake was suspended in 600 mL of sodium hydroxide (aqueous solution, 1 M) and stirred for 16 hours. The reaction mixture was filtered and the filter cake was washed with water until the pH was neutral. The particles were packed into a 4 × 250 mm PEEK column.

[0121] Example 4.2 The procedure was the same as in Example 4.1, but the product of Example 2.2 was used as the substrate.

[0122] Example 4.3 The procedure was the same as in Example 4.1, but the product of Example 2.3 was used as the substrate.

[0123] Example 4.4 The procedure was the same as in Example 4.1, but the product of Example 3.1 was used as the substrate.

[0124] BDGE - amine Example 5.1 20 g of the reaction product of Example 2.4 was suspended in 75 mL of dimethyl sulfoxide and 50 mL of 1,4 - butanediol diglycidyl ether. The mixture was heated to 40 °C and 50 mL of NaOH (aqueous solution, 1 M) was added. The reaction mixture was stirred for 5 hours. The mixture was filtered and the filter cake was washed with water until the pH became neutral. After repeating the whole procedure once more, 26.6 g of particles with a thick hydrophilic polymer layer were obtained. 15 g of these particles were suspended in a 1:1 v / v dimethyl sulfoxide / water mixture. 90 mL of N - methylpyrrolidine was added and the mixture was stirred at 70 °C for 3 hours. The reaction mixture was filtered and the filter cake was washed with water until the pH became neutral. The dried particles were suspended in 100 mL of water and the mixture was heated to 100 °C. 40 mL of sodium hydroxide solution (aqueous solution, 30%) was added and the reaction mixture was stirred for 35 hours. The mixture was filtered and washed with water until the pH became neutral. The particles were packed into a 4 × 150 mm column.

[0125] Example 5.2 The procedure was the same as in Example 5.1, but the product of Example 2.5 was used as the substrate.

[0126] Example 5.3 The procedure was the same as in Example 5.1, but the product of Example 2.6 was used as the substrate.

[0127] Example 5.4 The procedure was the same as in Example 5.1, but the product of Example 2.7 was used as the substrate.

[0128] Example 5.5 The procedure was the same as in Example 5.1, but the product of Example 2.8 was used as the substrate.

[0129] Example 5.6 The procedure was the same as in Example 5.1, but the product of Example 2.9 was used as the substrate.

[0130] Example 5.7 The procedure was the same as in Example 5.1, but the product of Example 2.12 was used as the substrate.

[0131] PEI - ammonium ion - crosslinked Example 6.0 5 g of the reaction product of Example 2.11 was suspended in 20 mL of dimethyl sulfoxide, and 10 g of glycidyltrimethylammonium chloride was added. The reaction mixture was stirred for 16 hours. The mixture was filtered, and the filter cake was washed with water until the pH became neutral. The dried particles were suspended in 50 mL of water, and 10 mL of 1,4 - butanediol diglycidyl ether was added. The reaction mixture was stirred at 60 °C for 3 hours. The mixture was filtered, and the filter cake was washed with water. The particles were suspended in 50 mL of sodium hydroxide (aqueous solution, 1 M) and stirred at 60 °C for 15 hours. The particles were packed into a 4 × 150 mm PEEK column.

[0132] Negative charge (COO - / SO3 - ) Titration method for determination Example 7 Completely protonated dry particles (0.9 - 1.0 g) of Examples 2.1 - 2.9 and 3 are each suspended in 20 mL of sodium hydroxide (aqueous solution, 0.05 M). The particles are shaken in the solution for 30 minutes. The suspension is centrifuged at 3800 RPM, and 12 mL of the supernatant is collected using a syringe. The solution is filtered through a syringe filter (0.45 μm). Exactly 10 mL of the filtered solution is transferred to a beaker and diluted with 50 mL of ultrapure water. The solution is titrated with a hydrochloric acid solution (aqueous solution, 0.05 M). The carboxylic acid and / or sulfuric acid content is calculated using the following formula:

[0133] [Number]

[0134] V NaOH = Volume of the transferred solution (mL) c NaOH = Concentration of NaOH (mol / L) c HCl = Concentration of HCl (mol / L) V EP = Volume used until the equivalence point (mL) m = Weight of the particles (g) Ion chromatography Example 8 Examples 4.1 to 4.4 were packed into a 4×250 mm column, and Example 6 was packed into a 4×150 mm column. Solutions of fluoride, chloride, nitrite, bromide, nitrate, monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), and dibromoacetic acid (DBA) were passed through the column at 15 °C at a flow rate of 0.8 mL / min using 9 mM KOH as the mobile phase. Figures 2 to 5 show the chromatograms obtained using such columns.

[0135] Examples 5.1 to 5.6 were packed into a 4×150 mm column, and solutions of fluoride, chloride, nitrite, bromide, nitrate, and dichloroacetic acid (DCA) were passed through the column at 30 °C at a flow rate of 0.8 mL / min using 6:1 mM Na2CO3 / NAHCO3 as the mobile phase.

[0136] Example 5.2 was further packed into a 4×150 mm column, and solutions of fluoride, chloride, nitrite, bromide, nitrate, monochloroacetic acid (MCA), monobromoacetic acid (MBA), and dichloroacetic acid (DCA) were passed through the column at 45 °C at a flow rate of 0.8 mL / min using 11 mM KOH as the mobile phase. The chromatogram is shown in Figure 6.

[0137] The selectivities (α) of DCA and DBA for chloride listed in Tables 1, 2, and Figure 7 were calculated from the chromatogram using the following equation.

[0138]

Equation

[0139] t DCA = retention time of dichloroacetic acid (DCA) t Cl = retention time of chloride (Cl) t DBA = retention time of dibromoacetic acid t0 = dead time The number of theoretical plates of DCA was calculated using the following equation.

[0140]

Equation

[0141] t DCA = retention time of dichloroacetic acid (DCA) W b , DCA = peak width of dichloroactic acid (DCA) TP = number of theoretical plates Determination of hydrophilicity The hydrophilicity was determined as follows: 1 g of the hydrophilized PS / DVB particles obtained after step c) or the hydrophilized particles of Examples 2.1 to 2.9 were each suspended in 20 mL of water using a Phoenix RA-VA-10 Vortex mixer, and the solution was shaken for 30 seconds. The particles remained suspended for 15 minutes, after which the particles began to settle at the bottom of the reagent tube, indicating the hydrophilicity of the particles. The reference particles PS / DVB (untreated; as provided in step a)) were subjected to the same test but were not suspended in water and remained on top of the aqueous layer.

[0142] The particles obtained after step b) or Examples 1.1 to 1.4 also form suspensions under the above-mentioned conditions.

[0143] Comparison of the stability between the ion exchange material according to Example 5.7 and Comparative Example D. Example 9 The chromatography columns of Example 5.7 and Comparative Example D were each flushed with 1 M NaOH (pH 14) at 60 °C at 0.8 mL / min for 30 hours and 20 hours, respectively. At various time points, as shown in Figure 12, the columns were rinsed with water for 1 hour, and the chloride retention time was measured at 30 °C at 0.8 mL / min using 9 mM KOH. From this, the capacity factor of chloride was calculated by k(Cl) = (Ret(Cl) - Ret(IP)) / Ret(IP). The results are shown in Figure 12.

[0144] Comparative Example Example A (Without reduction) 10 g of the reaction product of Example 1.1 was suspended in 37.5 mL of dimethyl sulfoxide and 25 mL of 1,4-butanediol diglycidyl ether. The mixture was heated to 40 °C, and 25 mL of NaOH (aqueous solution, 1 M) was added. The reaction mixture was stirred for 6 hours. The mixture was filtered, and the filter cake was washed with water until the pH became neutral. The entire procedure was repeated once, and then the remaining epoxide was reacted with 60 mL of N-methyl-2-pyrrolidone in a 1:1 v / v mixture of water / dimethyl sulfoxide (120 mL).

[0145] Example B (Partial reduction with triacetoxyborohydride and low M n (Functionalization with polyethyleneimine (600 Da)) 5 g of the particles of Example 1.1 were suspended in 40 mL of ethanol. 5 g of polyethyleneimine (M n = 600 Da) was added, followed by 0.25 mL of acetic acid. After stirring the mixture for 1 hour, 6.3 g of sodium triacetoxyborohydride was added. The reaction mixture was stirred for 15 hours. The mixture was filtered, and the filter cake was washed with water until the pH became neutral. The particles were functionalized with anionic exchange groups as described in 6.0.

[0146] Example C (Synthesis of particles without acid groups) A polyvinyl alcohol (PVA) solution was prepared by dissolving 6.4 g of PVA and 0.1 g of hydroquinone in 390 mL of water. To 320 g of this solution, 2.3 g of sodium dodecyl sulfate (SDS) was added. 14.3 g of divinylbenzene (55%), 25 g of acetoxystyrene, 29.2 g of toluene, 4.2 g of 3-methyl-1-butanol and 0.8 g of azobisisobutyronitrile were mixed to prepare an organic solution. The PVA / SDS solution and the organic solution were mixed and emulsified. Separately, 14.2 g of a suspension of polystyrene seed particles (16% in water / ethanol, 70 / 30 v / v) was mixed with 26.4 g of the PVA solution in a reactor. To this, the emulsion was added and stirred at room temperature for 24 hours. The solution was purged with argon, and polymerization was initiated by heating the solution to 70 °C, and the reaction mixture was stirred at 70 °C for 10 hours. The mixture was cooled to room temperature, and the particles were filtered. The residue was washed with water, followed by ethanol, water, ethanol, toluene and acetone. The particles were dried in vacuo.

[0147] 25.7 g of the particles were suspended in 130 mL of ethanol. 21 mL of 33% sodium hydroxide solution was added to the suspension, and the solution was stirred at 45 °C for 5.5 hours. The particles were washed with water until the pH became neutral and rinsed with acetone. The particles were dried in vacuo.

[0148] As described in Example 5.1, the particles were functionalized with anionic exchange groups. The particles were packed into a 4×150 mm column, and a solution of fluoride, chloride, nitrite, bromide, nitrate, monochloroacetic acid (MCA), and dichloroacetic acid (DCA) was passed through the column at 45 °C at a flow rate of 0.8 mL / min using 11 mM KOH as the mobile phase. The chromatogram is shown in Figure 7.

[0149] Example D 61.7 g of PS / DVB particles were suspended in 382 mL of acetic acid in a 1 L reactor connected to a thermostat. The reaction mixture was heated to 80 °C. 121 mL of hydrogen peroxide (35%) was slowly added dropwise over 2 hours. The reaction mixture was stirred for 24 hours, then cooled, filtered, washed with ultrapure water to neutral pH, and rinsed with ethanol. The filter cake was dried in a vacuum oven to obtain 66 g of the product.

[0150] Reduction with lithium aluminum hydride: 51.7 g of the dried oxidation product was suspended in 196 mL of dry tetrahydrofuran in a 1 L reactor and cooled to 5 °C using a thermostat. 92 ml of a 2.4 M solution of lithium aluminum hydride in tetrahydrofuran was carefully added with stirring. The reaction mixture was heated to 55 °C with stirring for 48 hours. The reaction was stopped by cooling to 0 °C and adding 80 ml of water within 60 minutes. The reaction mixture was then diluted and 150 ml of sulfuric acid was added with stirring. The reaction mixture was heated to 80 °C for 1 hour and then filtered off. This was washed with water to neutral pH and rinsed with acetone. The filter cake was dried to obtain approximately 50 g of the product. The entire procedure was repeated twice. This reaction produced a polymer support of 0.25 mmol / g.

[0151] As described in Example 4.1, the particles were functionalized with anionic exchange groups Figure 1 shows a schematic view of steps a) to c) of a method for producing an ion exchanger according to the present invention. In the first step, PS / DVB particles are provided as a polymer support. The particles are subjected to an oxidation treatment to introduce carboxylic acid groups, among other carbonyl groups, into the polymer support. The partial reduction step results in a mixture of hydroxy groups and carboxylic acid groups on the polymer support. The hydroxy groups may react with a polyfunctional compound as a polymer or a polymer precursor in a further step to form a polymer layer (the step is not shown).

[0152] Figure 2 shows a chromatogram obtained using the ion exchange material according to Example 4.1 containing 0.3 mmol / g COOH. The chromatogram shows the separation of haloacetic acids, namely monochloroacetic acid 1, monobromoacetic acid 2, dichloroacetic acid 3, and dibromoacetic acid 4 (solid line), with respect to five standard anions, namely fluoride, chloride, nitrite, bromide, and nitrate. The haloacetic acids show good separation with retention times in the range of 50 minutes for the haloacetic acids.

[0153] Figure 3 shows a chromatogram obtained using the ion exchange material according to Example 4.2 containing 0.36 mmol / g COOH. The selectivity of the haloacetic acids compared to the standard anions has changed compared to the example in Figure 2.

[0154] Figure 4 shows a chromatogram obtained using the ion exchange material according to Example 4.3 with 0.41 mmol / g. The haloacetic acids still show very good separation. The retention times of the haloacetic acids are shorter compared to the examples shown in Figures 2 and 3.

[0155] Figure 5 shows a chromatogram obtained using the ion exchange material according to Example 6.0 containing 0.82 mmol / g COOH. The separation of the haloacetic acids is still sufficiently good, and the retention times of the haloacetic acids are shorter compared to the retention times in Figures 2 to 4.

[0156] Therefore, the examples in Figures 2 to 5 show the influence of the amount of carboxylic acid groups on the separation characteristics and retention characteristics of the ion exchange material according to the present invention.

[0157] Figure 6 shows the chromatogram of Example 5.2 using 11 mM KOH as the mobile phase and a column temperature of 45°C. The chromatogram shows the separation of haloacetic acids, namely monochloroacetic acid 1, monobromoacetic acid 2, and dichloroacetic acid 3, with respect to five standard anions: fluoride, chloride, nitrite, bromide, and nitrate.

[0158] Figure 7 shows a comparative example of a column without carboxylic acid groups according to Example C. The chromatogram shows the separation of haloacetic acids, namely monochloroacetic acid 1 and dichloroacetic acid 3, with respect to five standard anions: fluoride, chloride, nitrite, bromide, and nitrate. The elution conditions were 0.8 mL / min, 45°C, and 20 mM KOH.

[0159] From Figures 6 and 7, it can be seen that the haloacetic acids in Figure 6 elute earlier. In the chromatogram of Figure 6, MCA elutes before chloride, and DCA elutes within 30 minutes. In the case of a column containing no carboxylic acid at all, MCA elutes after chloride, and even when the concentration of the eluate is 1.8 times higher than that in Figure 6, it takes 40 minutes to elute DCA. Therefore, it is interesting that the haloacetic acids elute earlier and the analysis time is shortened, so it has at least a small amount of COOH on the surface.

[0160] Figure 8 shows the relationship between the amount of lithium aluminum hydride and the amount of carboxylic acid groups detected on the support material for Examples 2.6 to 2.9. Thus, it can be seen that the amount of carboxylic acid can be controlled by the amount of reducing agent added.

[0161] Figure 9 shows the changes in the selectivity coefficient (circles) and the number of theoretical plates (triangles) of dichloroacetic acid (DCA) according to the amount of carboxylic acid groups for Examples 2.6 to 2.9.

[0162] Table 1 shows the selectivity of DCA and the influence on the theoretical plates due to the change in carboxylic acid content by changing the oxidation conditions while keeping the reduction conditions the same (Examples 2.4 and 2.5). Measurement conditions: 6:1 mM Na2CO3 / NaHCO3, 30 °C, 0.8 mL / min

[0163]

Table 1

[0164] Table 2 shows the influence of the SO3 - / COO - group compared to the COO - group only (Example 4.3) on the selectivity of DCA and DBA. Measurement conditions: 9 mM KOH, 30 °C, 0.8 mL / min.

[0165]

Table 2

[0166] Table 2 shows that the same amount of negative charge generated from SO3 / COOH compared to COOH only decreases the selectivity for DCA and DBA, and since the pk[[ID=3l]] a of SO3H is lower than that of COOH, this accelerates the elution of these haloacetic acids to a shorter retention time.

[0167] Figure 10 shows the chromatogram of Comparative Example A. Without the reduction step and adjustment of the amount of carboxylic acid groups, the support material is not suitable for the separation of haloacetic acids. The polymer layer is not sufficiently bonded. There are too many carboxylic acid groups and too few or no hydroxy groups capable of bonding the polymer layer, that is, the polymer or polymer precursor bonded to the carboxylic acid groups is removed from the surface again by the hydrolysis step. The capacity of the column created by the polymer layer is lost.

[0168] Figure 11 shows the chromatogram of Comparative Example B. In this example, a polymer layer is formed in which an anionic group and a cationic group are in proximity, and the net charge becomes zero in the region where ion exchange should occur. The different charges are not sufficiently spatially separated. Therefore, there is little interaction between the ion exchange material and the analyte solution, resulting in almost immediate elution of the anions.

[0169] Figure 12 shows the change in the chloride capacity of the ion exchange material according to Example 9. This example simulates the long-term use of each chromatography column by using a higher temperature. The higher temperature simulates the load of long-term use. From the figure, it can be seen that the capacity of the carboxylic acid in the amount of 0.1 mmol / g according to Example 5.7 remains stable over time even after being exposed to fairly severe alkaline conditions for a long time as used for the separation of the above anions. In contrast, the amount of carboxylic acid of 0.25 mmol / g according to Comparative Example D results in a decrease in capacity over time, indicating a less stable column and some degree of decomposition of the material over long-term use.

Claims

1. An ion exchange material for use as a stationary phase in an analytical or preparative separation process, particularly for separating anions, preferably haloacetic acids, wherein the material comprises: - a polymer support; - acid groups directly bonded to the surface of the polymer support, selected from the group consisting of sulfonic acid groups, carboxylic acid groups, or combinations thereof; - a polymer layer covalently bonded to the surface of the polymer support and containing anion exchange groups; wherein the amount of the acid groups ranges from 0.05 to 1.05 mmol / g, preferably from 0.1 to 0.9 mmol / g, particularly preferably from 0.16 to 0.85 mmol / g of the polymer support, and the acid groups and the anion exchange groups are preferably spatially separated by at least 10 nm, preferably at least 50 nm, most preferably at least 100 nm via the polymer layer. An ion exchange material characterized thereby.

2. The polymer support is: - at least partially derived from an aromatic hydrocarbon compound having at least two vinyl or allyl substituents, preferably at least partially derived from a divinylbenzene monomer, and - partially derived from a monomer selected from the group consisting of ethylvinylbenzene, vinyl acetate, styrene, and any combination thereof, The ion exchange material according to claim 1, wherein the relative amount of the aromatic hydrocarbon compound having at least two vinyl or allyl substituents, preferably the relative amount of the monomer derived from divinylbenzene, is preferably at least 50% by weight.

3. The polymer layer is: - from the reaction of the polymer support with an oligoamine or polyamine, or - from the reaction of the polymer support with at least one polyfunctional compound containing at least a first functional group reactive with an amine and / or a hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or a hydroxy group The ion exchange material according to any one of claims 1 or 2, which is derived from.

4. The polymer layer is: - the reaction of the polymer support with at least one polyfunctional compound containing at least a first functional group reactive with an amine and / or a hydroxy group, preferably an epoxy group, and at least a second functional group reactive with an amine and / or a hydroxy group, followed by - the reaction with an oligoamine or a polyamine The ion exchange material according to claim 1 or 2, which is derived from

5. The polymer layer is crosslinked with the at least one polyfunctional compound, and the at least one polyfunctional compound is - epoxides, especially 1,4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, poly(ethylene glycol) diglycidyl ether, resorcinol diglycidyl ether, glycerol diglycidyl ether, glycidol, - organic halogen-containing compounds, especially epichlorohydrin, epibromohydrin, 1,1'-oxybis[2-(2-chloroethoxy)ethane], 1,2-bis(2-chloroethoxy)ethane, bis(2-chloroethyl) ether, 1-chloro-3-iodopropane, 1,4-dibromobutane, 1,3-dibromopropane, - aldehydes, especially glutaraldehyde The ion exchange material according to claim 3 or 4, which is selected from

6. The oligoamine or polyamine is selected from the group consisting of polyallylamine, linear or branched polyethyleneimine (PEI), poly(2-methylaziridine), preferably branched PEI. The ion exchange material according to any one of claims 3 to 5.

7. As a stationary phase in an analytical or preparative separation process, preferably for use as the ion exchange material according to any one of claims 1 to 6, having an amount of acid groups in the range of 0.05 to 1.05 mmol / g, preferably 0.1 to 0.9 mmol / g, particularly preferably 0.16 to 0.85 mmol / g of the polymer support, and each acid group being spatially separated from the anion exchange group by at least 10 nm, preferably at least 50 nm, most preferably at least 100 nm. A method for producing an ion exchange material, the method comprising a) providing a polymer support; b) a step of oxidizing the polymer support in the presence of an oxidizing agent, preferably a peracid; c) A step of partially reducing the polymer support obtained in step b) with a reducing agent to obtain a hydrophilic polymer support; d) A step of reacting the product of step c) with at least one polymer or polymer precursor to obtain a polymer layer on the polymer support; e) A step of introducing an anion exchange group into the polymer layer; A method comprising steps c) and d) being carried out simultaneously or sequentially, wholly or partially.

8. The amount of the peracid in step b) is produced in the presence of an acid and hydrogen peroxide, and the ratio (mol / mol) of the acid to H ２ O ２ is within the range of 1.0:0.12 to 1.0:0.72, preferably 1.0:0.14 to 1.0:0.52, and most preferably 1.0:0.16 to 1.0:0.

44. The method according to claim 7.

9. The method according to any one of claims 7 to 8, wherein the amount of the reducing agent in step c) is in the range of 0.03 g to 1.0 g, preferably 0.05 g to 0.8 g, and most preferably 0.1 g to 0.5 g per 1.0 g of the polymer support obtained in step b) based on the dry weight of the polymer support.

10. The method according to any one of claims 7 to 9, wherein the amount of the at least one polymer or polymer precursor in step d) is in the range of 0.1 g to 10.0 g, preferably 0.5 g to 8.0 g, and most preferably 1.5 g to 7.0 g per 1 g of the polymer support obtained in step c) based on the dry weight of the polymer support.

11. The method according to any one of claims 7 to 10, wherein a cross-linking step f), that is, a step of treating the reaction product resulting from step e) with at least one polyfunctional compound, follows step e).

12. In step e), the polymer support of step d) is preferably reacted with a quaternary amine selected from the group consisting of glycidyltrimethylammonium chloride, glycidyldimethylethanolammonium chloride, and glycidyltriethylammonium chloride, or preferably a tertiary amine selected from the group consisting of N-methyl-2-pyrrolidone, N-methylmorpholine, N-methylpyrrolidine, N,N-dimethylethanolamine, N-methyldiethanolamine, N-methylpiperidine, N-ethylpiperidine, trimethylamine, and triethylamine. The method according to claims 7 to 11.

13. An ion exchange material for use as a stationary phase in an analysis or preparative separation process, particularly a chromatography process, obtainable by the method according to any one of claims 7 to 12.

14. A chromatography column filled with the ion exchange material according to any one of claims 1 to 6, particularly an ion exchange chromatography column.

15. A method for chromatographically separating an analyte, preferably an anion, more preferably a haloacetic acid, most preferably monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), and dibromoacetic acid (DBA), the method comprising contacting a solution containing the analyte with the ion exchange material according to any one of claims 1 to 6, particularly passing it through the chromatography column according to claim 14.

16. Use of an ion exchange material obtainable by the method according to any one of claims 1 to 6 and / or according to any one of claims 7 to 12 for the analysis or preparative separation of an analyte, preferably an anion, more preferably a haloacetic acid, most preferably for the separation of monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid, and dibromoacetic acid.

17. A method for preparing a chromatography column preferably having the ion exchange material according to any one of claims 1 to 6, the method comprising a step of adjusting the retention time of a haloacetic acid with respect to a standard anion, the retention time being adjusted by an acid group directly bonded to the surface of the polymer support, the acid group being selected from the group consisting of a sulfonic acid group, a carboxylic acid group, or a combination thereof, the amount of the acid group being in the range of 0.41 to 1.05 mmol / g, preferably 0.65 to 1.05 mmol / g, particularly preferably 0.85 to 1.05 mmol / g of the polymer support, or in the range of 0.05 to 0.19 mmol / g, preferably 0.05 to 0.16 mmol / g, particularly preferably 0.05 to 0.10 mmol / g of the polymer support.

Images