Process for producing anion exchangers

Abstract

The present invention relates to a novel method for producing anion exchangers.

Description

[Technical Field]

[0001] The present invention relates to a novel process for producing anion exchangers. [Background technology]

[0002] For example, a process for producing anion exchangers known from Patent Document 1 is the reaction of a chloromethylated vinyl aromatic polymer with ammonia to produce anion exchangers having primary amine groups. However, a drawback of this process is the low yield achieved in the reaction. Therefore, chloromethylated vinyl aromatic polymers are usually reacted with primary, secondary or tertiary amines and used as anion exchangers.

[0003] Reaction of chloromethylated vinyl aromatic polymers with ammonia, primary or secondary amines only results in ion exchangers with lower ion exchange capacities than predicted by theory, because one amine reacts multiple times with the chloromethylated groups, producing undesirable secondary crosslinks.

[0004] Patent Document 2 describes the reaction of chloromethylated vinyl aromatic polymers with hexamethylenetetramine to obtain aminomethylated vinyl aromatic polymers, the drawback being that only a small proportion of the nitrogen is bound to the polymer.

[0005] Another process for preparing anion exchangers with primary amine functional groups is known from U.S. Patent No. 5,627,493. In this process, a vinyl aromatic polymer is amidomethylated with bis(phthalimidomethyl) ether, followed by hydrolysis. The bis(phthalimidomethyl) ether is typically first prepared from phthalimide and formaldehyde in the presence of sulfuric acid, followed by addition of the vinyl aromatic polymer. After amidomethylation, the amidomethylated polymer is hydrolyzed with an acid or base to prepare anion exchangers with primary amine functional groups. These anion exchangers can be further converted to strongly basic, weakly basic, and mixed-basic anion exchangers with secondary, tertiary, and quaternary amine functional groups by functionalization with alkylating agents.

[0006] This process also has drawbacks because it produces unstable intermediates that complicate the reaction procedure and also produces by-products that must be processed or disposed of in tedious or expensive ways.

[0007] Processes for preparing anion exchangers are known from US Pat. No. 5,629,492 and US Pat. No. 5,629,492, in which a vinyl aromatic polymer is reacted with an organic nitrile and formaldehyde in a Friedel-Crafts-like catalytic alkylation at the phenyl ring to produce an acylaminomethylated vinyl aromatic polymer, which is hydrolyzed to give the anion exchanger.

[0008] This process also produces unstable intermediates, which complicates the reaction procedure and generates large amounts of solvents, which are environmentally problematic. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent No. B1000660 [Patent Document 2] Former East German Patent No. A79152 [Patent Document 3] European Patent No. B1078688 [Patent Document 4] Japanese Patent Application Publication No. 51-005392 [Patent Document 5] Japanese Patent Application Publication No. 51-034295 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, there remains a need for a process that overcomes the shortcomings of the prior art and provides a high yield of anion exchangers. [Means for solving the problem]

[0011] It has now surprisingly been found that chloromethylated vinyl aromatic polymers can be converted in good yields into anion exchangers by reaction with nitriles in the presence of a metal-containing catalyst and subsequent hydrolysis.

[0012] Thus, the present invention provides a compound of formula (I) [ka] (In the formula, [ka] is a vinyl aromatic polymer radical) In the process for producing an anion exchanger of formula (II) [ka] (In the formula, [ka] is as defined above) The chloromethylated vinyl aromatic polymer of formula (III) R 1 CN (III) (In the formula, R 1= linear, cyclic or branched C1-C8 alkyl, phenyl or benzyl, and phenyl and benzyl may be substituted by at least one linear, cyclic or branched C1-C8 alkyl group) in the presence of a metal-containing catalyst with at least one nitrile of formula (IV) [ka] (In the formula, R 1 is as defined above), and the amidomethylated vinyl aromatic polymer of formula (IV) is hydrolyzed in step b) by reaction with an acid or a base to give the anion exchanger of formula (I). DETAILED DESCRIPTION OF THE INVENTION

[0013] The scope of the present invention encompasses all definitions of radicals, parameters and explanations set out above and below in detail and mentioned in general terms or within preferred ranges, including the various combinations between each other, i.e., between the respective ranges and preferred ranges.

[0014] R 1 is preferably a linear or branched C1-C4 alkyl. Particularly preferably, R 1 = methyl, ethyl, n-propyl or isopropyl. Particularly preferably, R 1 = methyl.

[0015] R 1 = phenyl or benzyl, said phenyl or benzyl is preferably unsubstituted. If phenyl and benzyl are substituted, they are preferably substituted by a linear, cyclic or branched C1-C8 alkyl group.

[0016] In the context of the present invention, C1-C8-alkyl is a linear, cyclic or branched alkyl radical having 1 to 8 carbon atoms (C1-C8), even more preferably 1 to 4 carbon atoms (C1-C4). Preferably, C1-C8-alkyl is methyl, ethyl, n-propyl, isopropyl, n-, i-, s- or t-butyl, cyclopropyl, cyclobutyl, cyclopentyl, n-hexyl, cyclohexyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl. Particularly preferably, C1-C8-alkyl or C1-C4-alkyl is ethyl, methyl, n-propyl or isopropyl.

[0017] The chloromethylated vinyl aromatic polymer of formula (II) is preferably a copolymer of at least one monovinyl aromatic monomer selected from the group comprising styrene, vinyltoluene, ethylstyrene, α-methylstyrene, chlorostyrene or chloromethylstyrene and mixtures of at least one of these monomers, and at least one polyvinylaromatic compound (crosslinker) selected from the group comprising divinylbenzene, divinyltoluene, trivinylbenzene, triallyl isocyanurate, divinylnaphthalene and / or trivinylnaphthalene or mixtures of these polyvinylaromatic compounds.

[0018] The chloromethylated vinyl aromatic polymer of formula (II) used is particularly preferably a copolymer of styrene, even more preferably a copolymer of styrene-divinylbenzene. The styrene-divinylbenzene copolymer is a copolymer crosslinked with divinylbenzene. The chloromethylated vinyl aromatic polymer of formula (II) preferably has a spherical shape.

[0019] In the chloromethylated vinyl aromatic polymer of formula (II), -CH2-Cl is attached to a phenyl group.

[0020] The chloromethylated vinyl aromatic polymer of formula (II) used in the present invention preferably has a macroporous structure.

[0021] The terms "microporous" or "gel-like" / "macroporous" have already been described in detail in the literature, for example, Seidl, Malinsky, Dusek, Heitz, Adv. Polymer Sci., 1967, Vol. 5, pp. 113-213. Methods for measuring porosity, such as mercury porosimetry and BET measurement, are also described in the literature. The pores of the macroporous polymers of the chloromethylated vinyl aromatic polymers of formula (II) used in the present invention generally and preferably have an average diameter of 20 nm to 100 nm. The pore diameter is preferably measured using a mercury porosimeter.

[0022] The chloromethylated vinyl aromatic polymers of formula (II) used in the present invention preferably have a monodisperse distribution.

[0023] In this application, a monodisperse material is one in which at least 90% by volume or 90% by weight of the particles have a diameter falling within a ±10% interval from the most common diameter.

[0024] For example, for materials with a most common diameter of 0.5 mm, at least 90% by volume or 90% by mass is within the size interval of 0.45 mm to 0.55 mm; for materials with a most common diameter of 0.7 mm, at least 90% by volume or 90% by mass is within the size interval of 0.77 mm to 0.63 mm.

[0025] The chloromethylated vinyl aromatic polymer of formula (II) preferably has a diameter of 200 to 1500 μm.

[0026] The chloromethylated vinyl aromatic polymer of formula (II) preferably has the shape of a sphere.

[0027] The chloromethylated vinyl aromatic polymer of formula (II) preferably comprises 88 mol % to 98 mol % of monovinyl aromatic monomer, based on the total amount of substance of the polymer. The chloromethylated vinyl aromatic polymer of formula (II) preferably comprises 2 mol % to 12 mol % of polyvinyl aromatic monomer, based on the total amount of substance of the polymer.

[0028] The anion exchanger of formula (I) preferably has a diameter of 200 to 1500 μm.

[0029] The anion exchanger of formula (I) preferably has a macroporous structure.

[0030] The anion exchangers of formula (I) preferably have a monodisperse distribution.

[0031] The anion exchanger of formula (I) preferably comprises from 88 mol % to 98 mol % of monovinylaromatic monomer, based on the total amount of substance of the polymer.

[0032] The anion exchanger of formula (I) preferably comprises from 2 mol % to 12 mol % of polyvinylaromatic monomer, based on the total amount of substance of the polymer.

[0033] The chloromethylated vinyl aromatic polymer of formula (II) used in step a) is preferably prepared according to step 1a): 1a) reacting monomer droplets comprising at least one monovinylaromatic compound and at least one polyvinylaromatic compound and at least one initiator; and 1b) Chloromethylating the polymer from step 1a).

[0034] In step 1a), at least one monovinylaromatic compound and at least one polyvinylaromatic compound are used, however, it is also possible to use mixtures of two or more monovinylaromatic compounds and mixtures of two or more polyvinylaromatic compounds.

[0035] In the context of the present invention, the monovinylaromatic compound used in step 1a) is preferably styrene, vinyltoluene, ethylstyrene, α-methylstyrene, chlorostyrene or chloromethylstyrene.

[0036] These monovinyl aromatic compounds are preferably used in an amount of more than 50% by weight, based on the monomer or its mixture with other monomers, particularly preferably in an amount of 55% to 70% by weight, based on the monomer or its mixture with other monomers.

[0037] It is particularly preferable to use styrene or mixtures of styrene with the abovementioned monomers, preferably ethylstyrene.

[0038] In the context of the present invention, preferred polyvinylaromatic compounds for step 1a) are divinylbenzene, divinyltoluene, trivinylbenzene, triallyl isocyanurate, divinylnaphthalene or trivinylnaphthalene, particularly preferably divinylbenzene.

[0039] The amount of polyvinylaromatic compound used is preferably 1% to 20% by weight, particularly preferably 2% to 12% by weight, and particularly preferably 4% to 10% by weight, based on the monomer or its mixture with further monomers. The type of polyvinylaromatic compound (crosslinker) is selected depending on the subsequent use of the polymer. When divinylbenzene is used, commercially available grades of divinylbenzene containing not only isomers of divinylbenzene but also ethylvinylbenzene are sufficient.

[0040] Macroporous vinyl aromatic polymers are preferably formed by adding an inert substance, preferably at least one porogen, to the monomer mixture to create a macroporous structure in the polymer during polymerization. Particularly preferred porogens are hexane, octane, isooctane, isododecane, pentamethylheptane, methyl ethyl ketone, butanol or octanol and their isomers. Particularly suitable organic substances are those that dissolve in the monomer but are poor solvents or poor swelling agents (settling agents) for the polymer, such as aliphatic hydrocarbons (Farbenfabriken Bayer, German Patent No. 1045102 (1957); German Patent No. 1113570 (1957)).

[0041] US Patent No. B4382124 uses alcohols having 4 to 10 carbon atoms, which may also be suitably used in the context of the present invention as porogens for the preparation of macroporous vinyl aromatic polymers based on styrene / divinylbenzene, and also provides an overview of the preparation of macroporous vinyl aromatic polymers.

[0042] The porogen is preferably used in an amount of 25% to 45% by weight based on the amount of the organic phase.

[0043] In step 1a) it is preferred to add at least one porogen.

[0044] The vinyl aromatic polymers prepared according to step 1a) can be prepared in heterodisperse or monodisperse form.

[0045] The preparation of heterodisperse vinyl aromatic polymers is carried out using conventional processes known to those skilled in the art, such as suspension polymerization.

[0046] Preferably, monodisperse vinyl aromatic polymers are prepared in step 1a).

[0047] In a preferred embodiment of the present invention, microencapsulated monomer droplets are used in step 1a) in the preparation of monodisperse vinyl aromatic polymers.

[0048] Suitable materials for microencapsulation of the monomer droplets are those known for use as complex coacervates, in particular polyesters, natural and synthetic polyamides, polyurethanes or polyureas.

[0049] The natural polyamide used is preferably gelatin. It is used particularly as a coacervate and complex coacervate. In the context of the present invention, gelatin-containing complex coacervates are understood to mean a combination of gelatin with a synthetic polyelectrolyte. Suitable synthetic polyelectrolytes are, for example, copolymers incorporating maleic acid, acrylic acid, methacrylic acid, acrylamide, and methacrylamide units. The use of acrylic acid and acrylamide is particularly preferred. Gelatin-containing capsules can be hardened using conventional hardeners, such as formaldehyde or glutaric dialdehyde. The encapsulation of monomer droplets using gelatin, gelatin-containing coacervates, and gelatin-containing complex coacervates is described in detail in EP-A0 046 535. Methods of encapsulation using synthetic polymers are known. Interfacial condensation is preferred, in which a reactive component (especially an isocyanate or an acid chloride) dissolved in the monomer droplets is reacted with a second reactive component (especially an amine) dissolved in an aqueous phase.

[0050] Heterodisperse or optionally microencapsulated monodisperse monomer droplets contain at least one initiator or a mixture of initiators (combination of initiators) that cause polymerization.The initiator suitable for the process of the present invention is peroxy compound, particularly preferably dibenzoyl peroxide, dilauroyl peroxide, bis(p-chlorobenzoyl) peroxide, dicyclohexyl peroxydicarbonate, tert-butyl peroctoate, tert-butyl peroxy-2-ethylhexanoate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane or tert-amyl peroxy-2-ethylhexane, and also azo compounds, such as 2,2'-azobis(isobutyronitrile) or 2,2'-azobis(2-methylisobutyronitrile).

[0051] The initiator is preferably used in an amount of 0.05% to 2.5% by weight, particularly preferably 0.1% to 1.5% by weight, based on the monomer mixture.

[0052] The optionally monodisperse microencapsulated monomer droplets may also optionally contain up to 30% by weight (based on monomer) of a crosslinked or non-crosslinked polymer. Preferred polymers are those derived from the above-mentioned monomers, particularly preferably styrene.

[0053] In another preferred embodiment, the aqueous phase in step 1a) when preparing monodisperse vinyl aromatic polymers can contain dissolved polymerization inhibitors.In this case, useful inhibitors include both inorganic and organic substances.Preferred inorganic inhibitors are nitrogen compounds, particularly preferably hydroxylamine, hydrazine, sodium nitrite and potassium nitrite, phosphorous acid salts such as sodium hydrogen phosphite, and sulfur-containing compounds such as sodium dithionite, sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium thiocyanate and ammonium thiocyanate.Examples of organic polymerization inhibitors are phenolic compounds such as hydroquinone, hydroquinone monomethyl ether, resorcinol, catechol, tert-butylcatechol, pyrogallol, and the condensation reaction product of phenol and aldehyde.Another suitable organic polymerization inhibitor is a nitrogen-containing compound. Particularly preferred are hydroxylamine derivatives such as N,N-diethylhydroxylamine, N-isopropylhydroxylamine, and sulfonated or carboxylated N-alkylhydroxylamines or N,N-dialkylhydroxylamine derivatives, hydrazine derivatives such as N,N-hydrazinodiacetic acid, and nitroso compounds such as N-nitrosophenylhydroxylamine, N-nitrosophenylhydroxylamine ammonium salt, and N-nitrosophenylhydroxylamine aluminum salt. The concentration of the polymerization inhibitor (based on the aqueous phase) is 5 to 1000 ppm, preferably 10 to 500 ppm, and particularly preferably 10 to 250 ppm.

[0054] The polymerization of the optionally microencapsulated monodisperse monomer droplets to obtain monodisperse vinyl aromatic polymers is preferably carried out in the presence of one or more protective colloids in the aqueous phase. Suitable protective colloids are natural or synthetic water-soluble polymers, preferably gelatin, starch, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid, or copolymers of (meth)acrylic acid and (meth)acrylic acid esters. Further preferred are cellulose derivatives, especially cellulose esters and cellulose ethers, such as carboxymethyl cellulose, methylhydroxyethyl cellulose, methylhydroxypropyl cellulose, and hydroxyethyl cellulose. Gelatin is particularly preferred. The amount of protective colloid used is usually 0.05% to 1% by weight, preferably 0.05% to 0.5% by weight, based on the aqueous phase.

[0055] In an alternative preferred embodiment, the polymerization to obtain monodisperse vinyl aromatic polymers can be carried out in the presence of a buffer system. A buffer system capable of adjusting the pH of the aqueous phase at the start of the polymerization to a value between 14 and 6, preferably between 12 and 8, is preferred. Under these conditions, protective colloids containing carboxylic acid groups are present wholly or partially as salts, which has a favorable effect on the function of the protective colloid. Particularly suitable buffer systems contain salts of phosphoric acid or boric acid. In the context of the present invention, "phosphate" and "borate" also encompass the ortho-condensates of the corresponding acids and salts. The concentration of the phosphate or borate in the aqueous phase is preferably 0.5 to 500 mmol / L, particularly preferably 2.5 to 100 mmol / L.

[0056] The agitation speed in the polymerization to obtain monodisperse vinyl aromatic polymers is not very important and does not affect the particle size, in contrast to conventional polymerization. A low agitator speed is used that is sufficient to keep the suspended monomer droplets in suspension and promote the removal of polymerization heat. Various types of agitators can be used for this purpose. A particularly suitable agitator is a shaft-acting gate agitator.

[0057] The volume ratio of encapsulated monomer droplets to aqueous phase is preferably 1:0.75 to 1:20, particularly preferably 1:1 to 1:6.

[0058] The polymerization temperature for obtaining a monodisperse vinyl aromatic polymer is determined by the decomposition temperature of the initiator used. It is preferably 50 to 180°C, particularly preferably 55 to 130°C. The polymerization is preferably continued for 0.5 to about 20 hours. It has been found useful to initiate the polymerization at a low temperature, preferably 60°C, and use a temperature program in which the reaction temperature is increased as the polymerization conversion progresses. This makes it possible to achieve, in a highly effective manner, requirements such as reliable reaction progress and high polymerization conversion. After the polymerization reaction, the monodisperse vinyl aromatic polymer is isolated by a conventional method, such as filtration or decantation, and optionally washed.

[0059] The production of monodisperse vinyl aromatic polymers using the jet or seed-feed process is known from the prior art and is described, for example, in US Pat. No. 4,444,961, EP-A0 046 535, US Pat. No. 4,419,245 or WO 93 / 12167.

[0060] Preferably, the jet or seed-feed method is used to prepare the monodisperse vinyl aromatic polymers.

[0061] Step 1a) preferably comprises the preparation of a macroporous monodisperse vinyl aromatic polymer.

[0062] In step 1b), the vinyl aromatic polymer is converted by chloromethylation to a compound of formula (II): [ka] (In the formula, [ka] is a vinyl aromatic polymer) to a chloromethylated vinyl aromatic polymer of

[0063] In step 1b), chloromethyl methyl ether is preferably used as the chloromethylating agent. Chloromethyl methyl ether may be used in an impure state, for example, containing methylal and methanol as secondary components. In step 1b), chloromethyl methyl ether is preferably used in excess. The chloromethylation reaction is catalyzed by the addition of a Lewis acid. Suitable Lewis acids include iron(III) chloride, zinc chloride, tin(IV) chloride, and aluminum chloride. The reaction temperature in step 1b) is preferably in the range of 40 to 80°C. In a preferred embodiment, step 1b) is carried out at normal pressure and at a temperature of 50 to 60°C. During the reaction, volatile components, such as hydrochloric acid, methanol, methylal, formaldehyde, and some chloromethyl methyl ether, are preferably removed by evaporation. To remove remaining chloromethyl methyl ether and purify the chloromethylated product, the reaction mixture is preferably washed with a mixture of methylal, methanol, and water.

[0064] Step 1b) preferably leads to a macroporous chloromethylated vinyl aromatic polymer of formula (II).

[0065] The chloromethylated vinyl aromatic polymer of formula (II) prepared in step 1b) is preferably used as a reactant in step a).

[0066] In step a), it is preferred to use as nitriles of formula (III) acetonitrile, propionitrile, butyronitrile, isovalerylnitrile, benzonitrile, o-methylbenzonitrile, m-methylbenzonitrile, p-methylbenzonitrile and phenylacetonitrile. It is very particularly preferred that the nitrile of formula (III) used is acetonitrile.

[0067] In step a), inorganic or organic metal(II), metal(III) or metal(IV) salts or mixtures of such salts are preferably used as metal-containing catalysts. The metal-containing catalysts used are preferably iron(II) salts, iron(III) salts, zinc(II) salts, tin(II) salts or tin(IV) salts and mixtures of these compounds. The metal-containing catalysts used are particularly preferably: iron(II) chloride, iron(II) bromide, iron(II) nitrate, iron(II) sulfate, iron(II) perchlorate, iron(II) phosphate, iron(II) acetate, iron(III) chloride, iron(III) bromide, iron(III) nitrate, iron(III) sulfate, iron(III) perchlorate, iron(III) phosphate, iron(III) acetate, zinc(II) chloride, zinc(II) bromide, zinc(II) nitrate, sulfur, iron(III), iron(III) phosphate, iron(III) acetate, zinc(II) chloride, zinc(II) bromide, zinc(II) nitrate, sulfur, iron(III), iron(III), iron(III), iron(III), iron(III), zinc(III), zinc(II), phosphate, iron(III), zinc(III), zinc(II), zinc(II), nitrate, sulfur, iron(III), iron(III), iron(III), zinc(III), phosphate, iron(III), zinc(III), zinc(II), nitrate, sulfur, iron(III), iron(III), phosphate, iron(III), zinc(III), zinc(II), nitrate, sulfur, iron(III), iron(III), phosphate, iron(III), zinc(III), zinc(II), nitrate, sulfur, iron(III), phosphate, iron(III), zinc(III), zinc(II), nitrate, sulfur, iron(II), phosphate, iron(III), zinc(III), nitrate, sulfur, iron(II), nitrate, sulfur, iron(II), nitrate, sulfur, iron(II), nitrate, sulfur, iron(II), nitrate, sulfur, Zinc(II) perchlorate, zinc(II) perchlorate, zinc(II) phosphate, zinc(II) acetate, tin(II) chloride, tin(II) bromide, tin(II) nitrate, tin(II) sulfate, tin(II) perchlorate, tin(II) phosphate, tin(II) acetate, tin(IV) chloride, tin(IV) bromide, tin(IV) nitrate, tin(IV) sulfate, tin(IV) perchlorate, tin(IV) phosphate, or tin(IV) acetate, or a mixture of salts thereof. The metal-containing catalyst used is particularly preferably zinc(II) perchlorate, zinc(II) chloride, and iron(III) chloride, as well as their hydrates. The metal-containing catalyst used is very particularly preferably zinc(II) perchlorate, especially the hexahydrate.

[0068] In step a), the nitrile of formula (III) is preferably used in a ratio of 100:1 to 1:1, particularly preferably 50:1 to 1:1, based on the amount of chlorine in the chloromethylated vinyl aromatic polymer of formula (II) used.

[0069] In step a), the metal-containing catalyst is preferably used in a ratio of 1:100 to 1:1, particularly preferably 1:50 to 1:0.5, based on the amount of chlorine in the chloromethylated vinyl aromatic polymer of formula (II) used.

[0070] Step a) of the process according to the present invention can be carried out in the presence or absence of a polar or non-polar inert solvent. It is preferred that step a) of the process according to the present invention is carried out in the absence of a solvent. Suitable polar inert solvents are water or alcohols, preferably methanol, ethanol, propanol or butanol, or mixtures of these polar inert solvents.

[0071] Non-polar inert solvents which are preferably used are halogenated aliphatic or aromatic hydrocarbons, such as, preferably, dichloromethane, dichloroethane, dibromomethane, trichloromethane, tetrachlorocarbon or benzotrifluoride or mixtures of these solvents.

[0072] In a preferred embodiment of the present invention, the chloromethylated vinyl aromatic polymer of formula (II) is charged first and then contacted with the nitrile of formula (III) and the metal-containing catalyst, and the mixture is then heated to the reaction temperature.

[0073] The reaction temperature in step a) is preferably 60°C to 140°C, more preferably 70°C to 110°C.

[0074] In step a), the pressure is preferably in the range of 0.8 to 3 bar.

[0075] The reaction is preferably completed within a range of 1 to 24 hours, preferably within a range of 4 to 12 hours.

[0076] The work-up is carried out by processes known to those skilled in the art for the work-up of corresponding process reaction products, for example by neutralization and filtration of the amidomethylated vinyl aromatic polymer of formula (IV) thus obtained.

[0077] Hydrolysis of the amidomethyl group, i.e., the presentation of the aminomethyl group, is carried out by treatment with at least one base or at least one acid in step b). The base used in step b) to hydrolyze the amidomethylated vinyl aromatic polymer of formula (IV) is preferably selected from alkali metal hydroxides, alkaline earth metal hydroxides, ammonia, or hydrazine. The acid used in step b) is preferably nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid, sulfurous acid, or nitrous acid. In step b), it is preferred to use at least one base to hydrolyze the amidomethyl group, i.e., the presentation of the aminomethyl group.

[0078] When an acid is used for the hydrolysis in step b), the hydrolysis of the amidomethyl groups is preferably carried out at a temperature of 80° C. to 250° C., preferably 80° C. to 190° C. The concentration of the acid in step b) is preferably in the range of 5% to 90% by weight, particularly preferably 10% to 70% by weight, based on the aqueous phase.

[0079] The hydrolysis of the amidomethyl groups in step b), i.e. the presentation of aminomethyl groups, is particularly preferably carried out by treating the amidomethylated vinyl aromatic polymer of formula (IV) with an aqueous or alcoholic solution of an alkali metal hydroxide, such as preferably sodium hydroxide or potassium hydroxide, at temperatures between 80° C. and 250° C., preferably between 120° C. and 190° C. The concentration of the aqueous sodium hydroxide solution is preferably between 20% and 60% by weight, based on the aqueous phase.

[0080] The hydrolysis of amidomethyl groups to aminomethyl groups in step b) is preferably carried out using an excess of acid and / or base relative to the amount of amidomethyl groups used.

[0081] The anion exchanger of formula (I) formed in step b) is generally washed with deionized water until neutral, but it can also be used without post-treatment.

[0082] The anion exchangers of formula (I) can be further functionalized by known processes by reaction with alkylating agents to give secondary, tertiary and quaternary amine-containing anion exchangers and chelating resins.

[0083] The process of the present invention allows for the mass production of anion exchangers.

[0084] Measurement of the amount of basic groups 100 mL of aminomethylated polymer was shaken into a tamped volumetric flask and then washed into a glass column with deionized water. 1000 mL of 2 wt. % sodium hydroxide solution was filtered over 1 hour and 40 minutes. Then, deionized water was filtered with 100 mL of phenolphthalein-added eluent until a maximum consumption of 0.05 mL of 0.1 N (0.1 Normal) hydrochloric acid was reached.

[0085] 50 mL of this resin is mixed with 50 mL of deionized water and 100 mL of 1N hydrochloric acid in a beaker. The suspension is stirred for 30 minutes and then transferred into a glass column. The liquid is allowed to drain. An additional 100 mL of 1N hydrochloric acid is filtered through the resin over 20 minutes. 200 mL of methanol is then filtered. All eluates are collected, combined, and titrated with 1N sodium hydroxide solution using methyl orange indicator.

[0086] Calculate the amount of aminomethyl groups in 1 liter of aminomethylated resin according to the following formula: (200-V)*20 = molar amount of aminomethyl groups per liter of resin (where V is the volume of 1N sodium hydroxide solution consumed in the titration).

[0087] The molar amount of basic groups corresponds to the molar amount of aminomethyl groups in the resin.

[0088] Measurement of the amount of chloromethylated groups The amount of chloromethylated groups is calculated by determining the chlorine content of the dried resin by elemental analysis. [Example]

[0089] Example 1 1a) Preparation of monodisperse macroporous polymers based on styrene, divinylbenzene and ethylstyrene A 10 L glass reactor is first charged with 3000 g of deionized water and a solution of 10 g of gelatin, 16 g of disodium hydrogen phosphate dodecahydrate, and 0.73 g of resorcinol dissolved in 320 g of deionized water, and mixed. The temperature of the mixture is adjusted to 25°C. Next, while stirring, 3200 g of a mixture of microencapsulated monomer droplets with a narrow particle size distribution consisting of 3.1 wt. % divinylbenzene and 0.6 wt. % ethylstyrene (commercially available in the form of an isomeric mixture of divinylbenzene and ethylstyrene (80% divinylbenzene)), 0.4 wt. % dibenzoyl peroxide, 58.4 wt. % styrene, and 37.5 wt. % isododecane (a technical-grade isomeric mixture with a high pentamethylheptane content), the microcapsules consisting of a complex coacervate containing gelatin and a copolymer of acrylamide and acrylic acid hardened with formaldehyde, is added, and 3200 g of an aqueous phase with a pH of 12 is added.

[0090] The mixture is stirred and the polymerization is completed by increasing the temperature according to a temperature program starting at 25° C. and ending at 95° C. The mixture is cooled, washed through a 32 μm sieve, and then dried at 80° C. under reduced pressure.

[0091] This gives 1893 g of polymer with a monodisperse particle size distribution. The average diameter of the pores in the polymer is 42 nm.

[0092] 1b) Chloromethylation of monodisperse macroporous polymers from 1a) First, 1120 mL of a mixture of monochlorodimethyl ether, methylal, and iron(III) chloride (14.8 g / L) was charged into a 2-L sulfonation flask, followed by the addition of 240 g of the bead polymer from 1a). The mixture was heated to 50°C and stirred under reflux at 50-55°C for 6 hours. During the reaction, hydrochloric acid and low-boiling organic compounds were evaporated / removed by distillation. The reaction suspension was then vigorously washed successively with 1200 mL of methanol, 2400 mL of methylal, 1200 mL of methanol three times, and finally with deionized water. This yielded 590 mL of a monodisperse macroporous chloromethylated polymer containing water and having a chlorine content of 21.9 wt%.

[0093] Example 2 Reaction of the chloromethylated vinyl aromatic polymer from Example 1b) with acetonitrile and iron(III) chloride to obtain the amidomethylated vinyl aromatic polymer of formula (IV) First, 21 g of the wet chloromethylated product from Example 1b (0.13 mol Cl) is placed in a round-bottom flask and washed twice with 100 mL of acetonitrile each time. 150 mL of acetonitrile (2.8 mol) and 35.1 g of iron(III) chloride hexahydrate (0.13 mol) are then added to the beads. The mixture is heated under reflux for 6 hours, then cooled and mixed with 150 mL of 7% by weight aqueous hydrochloric acid at room temperature. The beads are separated from the reaction solution by filtration and washed three times with 200 mL of deionized water each time. Yield: 64 mL of resin Nitrogen content: 5.5% by weight (dry resin)

[0094] Example 3 Reaction of the chloromethylated vinyl aromatic polymer from Example 1b) with acetonitrile and zinc(II) chloride to obtain the amidomethylated vinyl aromatic polymer of formula (IV) First, 21 g of the wet chloromethylated product from Example 1b (0.13 mol Cl) is placed in a round-bottom flask and washed twice with 100 mL of acetonitrile each time. 150 mL of acetonitrile (2.8 mol) and 8.9 g of zinc(II) chloride (0.07 mol) are then added to the beads. The mixture is heated under reflux for 6 hours, then cooled and mixed with 150 mL of 7% by weight aqueous hydrochloric acid at room temperature. The beads are separated from the reaction solution by filtration and washed three times with 200 mL of deionized water each time. Yield: 61 mL of resin Nitrogen content: 4.6% by weight (dry resin)

[0095] Example 4 Reaction of the chloromethylated vinyl aromatic polymer from Example 1b) with acetonitrile and zinc(II) perchlorate hexahydrate to obtain the anion exchanger of formula (I) a) First, 165.8 g of the wet chloromethylated product from Example 1b) (1.085 mol Cl) are placed in a round-bottom flask and washed twice with 500 mL of acetonitrile each time. 1200 mL of acetonitrile (22.4 mol) and 201.1 g of zinc(II) perchlorate hexahydrate (0.54 mol) are then added to the beads. The mixture is heated under reflux for 20 hours, then cooled and mixed with 1200 mL of 7% by weight aqueous hydrochloric acid at room temperature. The beads are separated from the reaction solution by filtration and washed three times with 200 mL of deionized water each time. Yield: 548 mL of resin Nitrogen content: 7.0% by weight (dry resin)

[0096] b) Hydrolysis of the amidomethylated vinyl aromatic polymer from Example 4a) 103.2 g of 50 wt% aqueous sodium hydroxide solution and 232 mL of deionized water are added to 250 mL of the amidomethylated polymer from Example 4a) at room temperature. The suspension is heated to 180°C over 2 hours and stirred at that temperature for 8 hours. The polymer thus obtained is washed with deionized water. Yield of aminomethylated polymer: 188 mL Measurement of the amount of basic groups: 2.17 mol / L resin

[0097] Example 5 Reaction of the chloromethylated bead polymer from Example 1b) with benzonitrile and zinc(II) chloride to obtain the amidomethylated vinyl aromatic polymer of formula (IV) First, 17 g of the wet chloromethylated product from Example 1b) (0.11 mol Cl) are placed in a round-bottom flask and washed twice with 50 mL of benzonitrile each time. 120 mL of benzonitrile (1.15 mol) and 7.2 g of zinc(II) chloride (0.05 mol) are then added to the beads. The mixture is heated at 80°C for 6 hours, then cooled and mixed with 120 mL of 7% by weight aqueous hydrochloric acid at room temperature. The beads are separated from the reaction solution by filtration and washed three times with 200 mL of acetone each time and three times with 200 mL of deionized water each time. Yield: 50 mL of resin Nitrogen content: 3.5% by weight (dry resin)

Claims

1. Formula (I) 【Chemical 1】 (In the formula, 【Chemistry 2】 is a vinyl aromatic polymer radical) In the process for producing an anion exchanger of formula (II) in step a) 【Chemistry 3】 (In the formula, 【Chemistry 4】 is as defined above) The chloromethylated vinyl aromatic polymer of formula (III) R １ CN (III) (In the formula, R １ = linear, cyclic or branched C １ ~C ８ alkyl, phenyl or benzyl, and said phenyl and benzyl are selected from at least one linear, cyclic or branched C １ ~C ８ - may be substituted by alkyl groups) in the presence of a metal-containing catalyst to form a compound of formula (IV): 【Chemistry 5】 (In the formula, R １ is as defined above) and the amidomethylated vinyl aromatic polymer of formula (IV) is hydrolyzed in step b) by reaction with an acid or a base to give the anion exchanger of formula (I).

2. In formula (III), R １ = linear or branched C １ ~C ４ 2. The process of claim 1, wherein the alkyl is -alkyl.

3. 3. A process according to claim 1 or 2, characterized in that the nitrile of formula (III) used is acetonitrile.

4. 4. The process according to claim 1, wherein the metal-containing catalyst used is an inorganic or organic metal(II), metal(III) or metal(IV) salt or a mixture of said salts.

5. 5. The process according to any one of claims 1 to 4, characterized in that the metal-containing catalyst used is an iron(II) salt, an iron(III) salt, a zinc(II) salt, a tin(II) salt or a tin(IV) salt and mixtures thereof.

6. 6. The process according to any one of claims 1 to 5, characterized in that the metal-containing catalyst used is zinc(II) perchlorate, zinc(II) chloride and iron(III) chloride, as well as their hydrates or mixtures thereof.

7. 7. The process according to any one of claims 1 to 6, characterized in that the metal-containing catalyst used is zinc(II) perchlorate.

8. A process according to any one of claims 1 to 7, characterized in that the chloromethylated vinyl aromatic polymer of formula (II) used is a chloromethylated styrene copolymer.

9. 9. A process according to claim 8, characterized in that the chloromethylated vinyl aromatic polymer used is a chloromethylated styrene-divinylbenzene copolymer of formula (II):

10. 10. The process according to any one of claims 1 to 9, characterized in that step a) uses the nitrile of formula (III) in a ratio of 100:1 to 1:1, based on the amount of chlorine in the chloromethylated vinyl aromatic polymer of formula (II) used.

11. 11. The process according to any one of claims 1 to 10, characterized in that step a) uses a metal-containing catalyst in a ratio of 1:100 to 1:0.5, based on the amount of chloromethylated vinyl aromatic polymer of formula (II) used.

12. 12. The process according to any one of claims 1 to 11, characterized in that the chloromethylated vinyl aromatic polymer of formula (II) contains 88 mol% to 98 mol% of monovinylaromatic monomer and 2 mol% to 12 mol% of polyvinylaromatic monomer, based on the total amount of substance of the polymer.

13. 13. The process according to any one of claims 1 to 12, characterized in that the chloromethylated vinyl aromatic polymer of formula (II) used in step a) is prepared by reacting in step 1a) monomer droplets of at least one monovinylaromatic compound and at least one polyvinylaromatic compound and at least one initiator, and chloromethylating in step 1b).

14. The process according to any one of claims 1 to 13, characterized in that the hydrolysis in step b) is carried out at a temperature between 80°C and 250°C.

15. 15. A process according to any one of claims 1 to 14, characterized in that step a) uses a chloromethylated macroporous vinyl aromatic polymer of formula (II).

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