CA1067648A

CA1067648A - Process for the production of anion exchangers

Info

Publication number: CA1067648A
Application number: CA224,843A
Authority: CA
Inventors: Michael Lange; Gunter Naumann
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1974-04-19
Filing date: 1975-04-17
Publication date: 1979-12-04
Also published as: DE2418976C3; IT1035350B; FR2268042A1; FR2268042B1; NL173276C; BR7502346A; IL47094A0; HU170783B; ZA752512B; DE2418976A1; BE828034A; GB1497828A; AR208907A1; ES436747A1; DE2418976B2; TR18466A; CS189707B2; JPS5418715B2; NL173276B; JPS50141592A

Abstract

Abstract of the Disclosure This invention relates to a new process for the production of crosslinked, water-insoluble synthetic resins with anion exchanger properties wherein the crosslinked, water-insoluble organic polymers con-taining aromatic nuclei are reacted, in the presence of swelling agents for the polymer and in the presence of acid catalysts, with esters of N-hydroxyalkyl-amides or N-hydroxyalkylimides, and the acylamido alkylated reaction product is subsequently hydro-lysed in known manner. The invention furthermore concerns new crosslinked water-insoluble synthetic resins with anion exchanger properties containing at least two aminoalkyl groups per aromatic nucleus.

Description

~,o67648 A process for the production of anion exchangcrs - This invention relates to a new process for theproduction of crosslinked, water-insoluble synthetic resins with anion exchanger properties by introducing aminoalkyl groups into crosslinked, water-insoluble organic polymers containing aromatic nuclei, distinguished by the fact that ; the crosslinked, water-insoluble organic polymers containing aromatic nuclei are reacted, in the presence of swelling agents for the polymer and in the presence of acid catalysts, with esters of N-hydroxyalkylimides, and the acylamido alkylated reaction product is subsequently hydrolysed in i~ known manner.
'~! The esters used in accordance with the invention are, above all, the esters of N-hydroxyalkylimides with lower -~
aliphatic or aromatic mono- or dicarboxylic acids, such as formic acid, butyric acid, valeric, succinic, maleic, benzoic and phthalic acid or, preferably, C2- or C3-alkane carboxy-lic acids, such as acetic acid and propionic acid, or in-organic oxygen-containing acids, such as sulphuric acid and phosphoric acid or acid esters thereof.
As N-h~droxy alkyl imides to be used there should be mentioned besides N-hydroxy ethyl imides, above all, the hydr~xy meth~l imides of saturated or unsaturated aliphatic C4-C6 dicarboxylic acidsl such as succinic acid, glutaric acid, adipic acid, diglycolic acid, maleic acid or aromatic ; o-dicarboxylic acids such as phthalic acid.

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10~i76~8 The crosslinked, water-insoluble organic polymers containing aromatic nuclei are preferably aromatic vinyl compounds of the type obtained by the copolymerisation of monovinyl and polyvinyl compounds. Copolymers of this kind are known per se and are obtained by known methods. The copolymers may be both microporous, i.e. have a gel structure, or macroporous.
It is preferred to use copolymers of the kind consisting predominently of aromatic monovinyl compound-c and to a far lesser extent of aromatic or aliphatic poly-vinyl compounds. The proportion of polyvinyl compounds act-ing as crosslinking agents may vary within wide limits. In the case of copolymers of gel structure, the polyvinyl compounds are generally used in quantities of from O.S to 20 % by weight and preferably in quantities of from 0.5 to 10 % by weight, whereas in the case of macroporous co-polymers the polyvinyl compounds are generally used in quantities of from 2 to 50 % and preferably in quantities ` of from 2 to 20 %.
The following are mentioned as examples of aro-matic monovinyl compounds: vinyl naphthalene, substituted styrenes, such as vinyl toluene, vinyl anisol, ethyl styrene and, in particular, styrene.
The following are mentioned as examples of poly-vinyl compounds: divinyl pyridine, divinyl toluenes, divinyl : naphthalenes, diallyl phthalate, ethylene glycol diacrylateJ
divinyl xylene, divinyl ethyl benzene, divinyl sulphone, polyvinyl or polyallyl ethers of glycol, glycerol and penta-' :

erythritol, divinyl ketone, divinyl sulphide, allyl acrylate, diallyl maleate, diallylfumarate, diallyl succinate, diallyl carbonate, diallyl malonate, diallyl oxalate, diallyl adipate, diallyl sebacate, diYinyl sebacate, diallyl tartrate, diallyl silicate, triallyl tricarballylate, triallyl aconitate, triallyl citrate, triallyl phosphate, N,N'-methylene diacrylamide, N,N'-methylene dimethacrylamide, N,N'-ethylene diacrylamide, l,~-di-(~-methyl methylene sulphonamido)-ethylene, trivinyl ben~ene, trivinyl naphthalene, polyvinyl anthracenes and in particular, divinyl benzene, trivinyl cyclohexane and ethylene glycol dimethylacrylate.
It is also possible to use crosslinked aromatic vinyl copolymers prepared with additions of other vinyl com-pounds such as, for example, methacrylic and acrylic com-pounds, especially acrylonitrile, ethylene, propylene, isobutylene, vinyl chloride, vinylacetate, vinylidene chloride, vinyl pyridine and substituted vinyl pyridines, and also vinyl quinolines and vinyl pyrrolidone. Other suit-able additives include polyethylenically unsaturated compounds such as isoprene, butadiene, chloroprene, piperylene, penta-diene, hexadiene, octadiene, decadiene, hexatriene, cyclo-pentadiene and substitution products thereof, for example chloroprene, 2,3-di~ethyl butadiene, 2,5-dimethyl hexadiene and 2,5-dimethyl octadiene, which generally behave as if they had only one double bond. The additives may be used in any quanti~ies. However, copolymers containing the above-mentioned additives in a quantity of more than 10 % Cbased on the total weight of the =onomers) are of little interest 106764~
so far as the production of anion-exchanging synthetic resins are concerned, because synthetic resins with a relatively low ion-exchange capacity would be obtained in their case.
Suitable swelling agents for the polymer are, above all, halogenated hydrocarbons such as dichloromethane, carbon tetrachloride, dichloroethane, trichlorethylene, symmetrical tetrachlorethane, 1,1,2-~richlorethane, tetrachlorethylene, di-chloropropane, pentachlorethane, trichloropropanesJ tetrachloro-propanes and also polar organic solvents such as dimethyl formamide, dimethyl sulphoxide and sulpholan, aliphatic or aromatic hydrocarbons substituted by nitro groups such as 1-nitropropane, 2-ni~ropropane, nitroethane or nitrobenzene. The above-mentioned swelling agents may be used either individually or in admixture with one another.
The halogen-free swelling agents, such as nitro-benzene, nitroethane, nitropropane, dimethyl sulphoxide or sulpholan, are used with advantage when the anion-exchangers , to be produced must not give off any halogens, for example ^ chlorîne, as is required, for example, in the case of anion 20 - exchangers intended for use in nuclear power s~ations.
Suitable acid catalysts include Friedel-Crafts catalysts such as zinc chloride, aluminium chloride, tin s tetrachloride, iron (III) chloride and above all, strong or-ganic acids, for example aliphatic and aromatic sulphonic acids such as methane, benzene and toluene sulphonic acid, and strong inorganic acids, especially oxygen-containing acids such as phosphoric acid and its acid esters, and above all sulphuric acid (concentrated or fuming). Mixtures of inorganic oxygen-containing acids, such as sulphuric acid, `

1067~;48 and lower aliphatic carboxylic acids or their anhydrides> for example acetic acid or acetic acid anhydride, have also proved to be effective.
The reaction according to the invention of the organic polymers with the esters N-hydroxy alkyl imides is generally carried out at temperatures in the range of from 0 to 150 C and preferably at temperatures in the range of from 30 to 100C.
The esters are used with advantage in such quantities that there are from 0.5 to 4 mols and preferably from 1 to 2.5 mols of ester to 1 mol of aromatic unit, i.e. per mol of aromatic nuclei, in the polymer.
The quantities of acid catalysts may vary within wide limits. In general, it has proved to be advantageous to use the acid catalysts in quantities of from 0.1 to 1.5 mols and preferably in quantities of from 0.75 to 1.25 mols per mol of ester.
The reaction is advantageously carried out by initially preparing the esters of the N-hydroxy alkyl imides, -the swelling agents used optionally serving simultaneously 2Q as solvents for the esterification reaction, and swelling the ~ .
polymers in these solutions of the esters. The reaction between the esters and the polymer takes place after the acid catalysts have been added and the requisite reaction temperature adjusted.
On completion of the acylaminoalkylation reaction, the acyl radical is split off from the reaction products in known manner, for example by subjecting the acylamino alkylation products to alkaline or acid hydrolysis, or by reaction with hydrazine followed by acid hydrolysis, optionally in the pre-sence of organic solvents or swelling agents. For hydrolysis, _ 5 _ .

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106764~3 the acyla~ino alkylation product is advantageously separated off from the reaction medium, for example by filtration under suction.
The isolated product may optionally be dried or washed with an organic water-miscible solvent, for example methanol, ethanol, dioxan or tetrahydrofuran. The product separated off is then hydrolysed in an autoclave at temperatures of between 100 and 250C with approximately 5 to 40 % strength by weight of an aqueous or alcoholic solution of an alkali, such as sodium hydroxide or potassium hydroxide, or with an approximately 5 to 80 % strength by weight aqueous solution of a mineral acid or sulphuric acid. On the other hand, the acylamino alkylation product may also be reacted with a S to 50 % strength by weight aqueous or alcoholic solution of hydrazine hydrate at temperatures in the range of from 50 to loo&. In one pre-- ferred embodiment, this particular solution may contain other alkalis, especially caustic alkalis, in quantities of from 1 to 20 % by weight. The reaction product may be isolated, .
washed with water and subsequently heated with an aqueous solution of mineral acid ~5 to 20 % strength in order to com-plete hydrolysis.
The aminoalkyl compounds prepared in accordance with the invention may be further modified in known manner by alkylation using known alkylating agents such as alkyl halides, for example methyl, ethyl, propyl chloride or bro-mide, dialkyl sulphates, for example dimethyl sulphate, alkylene oxides, for example ethylene or propylene oxide, halogen hydrins, polyhalogen compounds epihalohydrins, ethy-lene icinas or forraldahyda formic acid =ixturas.

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:1067648 It is possible by virtue of the process according to the invention to produce water-insoluble anion-exchanging synthetic resins containing aminoalkyl groups with a high, hîtherto unattained anion-exchange capacity coupled with high grain stability, in a technically simple and safe manner.
The present invention furth0rmore concerns new amino-alkyl group containing water-insoluble synthetic resins with anion ; exchanger properties; these resins are characterised by containing at least two aminoalkyl groups per aromatic nucleus.
The new aminoalkyl group containing water-insoluble synthetic resins with anion exchanger properties are pre~erably at least two aminoalkyl groups, especially aminomethyl groups, per aromatic nucleus containing microporous (gel-type~ copolymers of aromatic monovinyl compounds and 0.5 to 7 % by weight based on the .; .
w0ight of the copolymer, of polyvinyl compounds and macroporous at least two aminoalkyl groups, especially aminomethyl groups, per aromatic nucleus containing copolymers of aromatic monovinyl com- -pounds and 2 to 10 % by weight based on the weight of the copolymer of polyvinyl compounds, the porosity of said copolymers resulting from polymerisation in the presence of 40 to 100 ~ by weight based on the weight of the nomers of/an inert organic liquid. (Inert -j organic liquid = organic liquid which is a solvent for the mono-mers but a nonsolvent for the polymers).
`~ The new aminoalkyl group containing water-insolublesynthetic resins with anion exchanger properties are besides for other uses excollent suitablo as filter ; ~ 7 ~

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materials in filters of cigare~tes.
Various processes for the production of water-insoluble anion-exchanging synthetic resins containing animoalkyl groups have been proposed.
The advantage of the process according to the invention over the aminoalkylation processes known from German Patent Nos. 829,223 issued January 24, 1952, 841,796 issued June 19, 1952 and 848,257 issued September 1, 1952 all to Rohm ~ Haas Company and from German Offenlegungsschrift Nos.

2,161,628 published June 14, 1973 and 2,211,134 published September 13, 1973 both to Bayer AG and German O.S. No 2,248,528 published May 3, 1973 to Rohm Haas Company is that a much higher substitution of the polymer and, hence, a much higher anion-exchange capacity is obtained by the process according to the invention. In addition, the process according to the invention affords the commercially significant advantage, in cases where strong acids~ especially sulphuric acid, are used as the acid catalysts, that the formation of mono-chloromethyl and/or bisdichloromethyl ethers is avoided. The use and forma-tion of these highly toxic compounds in the processes described in German Patent Specifications Nos. 829,223; 841,796 and 848,257, and in German Offenlegungsschrift Nos. 2,211, 134, is a serious disadvantage of those processes.
;~ 20 It should also be emphasized that the resin grains of microporous polymers remain intact during acylamino alkylation by the process according to the invention, whereas a large proportion of the grains split open during acylamino alkylation by the process described in German Offenlegungsschri~t No. 2,161,628.

700 g of N-hydroxymethyl phthalimide, dissolved in 2400 g of dichloreehane~ are heated for S hours to reflux ' ~ ' ' , . '' .:

1067~48 temperatures with 454 g of acetic acid anhydride. 300 g of a styrene polymer crosslinked with 6 % of divinyl benzene are swollen in this ester solution over a period of 30 minutes at 60C. 400 g of concentrated sulphuric acid are then added dropwise over a period of 4 hours at reflux temperature. After stirring for 20 hours at the same temperature, the polymer is filtered off under suction and suspended in 2000 ml of 10 % aqueous ammonia solution. The residues of swelling agent are removed from the suspension by azeotropic distillation. The polymer is then heated for 10 hours to 180C with 40 %
sodium hydroxide solution in an autoclave. After the scdium hydroxide has been washed out, 750 ml of a ; weakly basic anion exchanger are obtained with an acid binding capacity of 3.3 Yal/l for N/10 hydrochloric acid and a nitrogen content of 9.55 % in the dry material.
~XAMPLE 2 354 g of N-hydroxymethyl phthalimide, dissolved ~, in 1100 g of dichlorethane, are heated for 5 hours to reflux temperature with 227 g of acetic acid anhydride.
150 g of a styrene polymer crosslinked with 4 % of divinyl benzene are swollen in this es~er solution over a period of 30 minutes at 60C. 240 g of concentrated sulphuric acid are then added dropwise over a period of 1 hour at ren ux te~perature, and the reaction mixture is stirred at the same temperature for a period of 20 hours. After the reaction product has been separated off, it is i suspended in 1000 ml of 10 % aqueous ammonia solution.
The residues o dichlorethane are removed from this suspension ~y azeotropic distillation. The reaction ` product is then separated off and hydrolysed by heating _ g _ for 10 hours to 180C with 40 % sodium hydroxide solution in an autoclave. After ~he sodium hydroxide has been washed out, a weakly basic anion exchanger is obtained with an acid-binding capacity of 3.0 Val/l for N/10 hydro-chloric acid and a nitrogen content of 10.4 % in the dry material.
By using instead of 240 g of concentrated sul-phuric acid 420 g of p-toluene sulphonic acid as catalyst, practically the same result was achieved.

160 g of a styrene polymer crosslinked with 2 %
of divinyl benzene are reacted, followed by hydrolysis, in the same way as described in Example 1. A weakly basic anion exchanger with an acid-binding capacity of 2.87 Val/l for N/10 hydrochloric acid and a nitrogen content of 18.2 % in the dry material is obtained.

245 g of an ester, obtained by reacting N-hydroxy-methyl phthalimide and acetic acid anhydride, are dissolved 2Q in 600 ml of 2-nitropropane. 100 g of a styrene bead poly-mer crosslinked with 6 % of divinyl benzene are swollen in this solution over a period of 30 minutes. The mixture is then heated to 85C, followed by the dropwise addition with stirring of 125 g of concentrated sulphuric acid. The reaction mixture is then kept at the same temperature for ; another 16 hours. The reaction product is then separated off and suspended in aqueous am~onia solution. The suspen-sion is freed from residues of the swelling agent by azeotropic distillation. The reaction product is separated 3Q off and hydrolysed in an autoclave with 40 % sodium hydro-xide solution at a temperature above 180C. A weakly basic anion exchan~er is obt-ined which, after the sodium hydroxide 10~6764~

has been washed out, has an acid-binding capacity for N/10 hydrochloric acid of 3.3 Val/l and a nitrogen content of 9.45 % in the dry material.

354 g of N-hydroxymethyl phthalimide, dissolved in 1200 g of dichlorethane, are heated for 5 hours to ~ reflux temperature with 227 g of acetic acid anhydride.
; After cooling to 60C, 150 g of a macroporous styrene polymer crosslinked with 8 % of divinyl benzene (obtain-ed by the bead polymerisation of styrene and divinyl benzene in the presence of 60 % by weight of isododecane, based on the sum total of nomers) are swollen in this solution over a period of 30 minutes. The mixture is then heated to re1ux temperature, followed by the drop-wise addition with stirring over a period of 4 hours of 240 g of concentrated sulphuric acid. After stirring for another 20 hours at the same temperature, the reaction product is separated off and free from the dichlorethane adhering to it by suspension in aqueous ammonia solution, followed by azeotropic distillation, in ~he same way as described in Example 1. The polymer is then heated for lO hours to 180C with 40 % sodium ; hydroxide solution in an autoclave. After the sodium hydroxide has been washed out, 540 ml of a weakly basic anion exchanger are obtained with an acid-binding capacity for N/10 hydrochloric acid of 2.4 Vsl/l and a nitrogen content of 10.6 % in the dry material.

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~067648 F~A~Il'I~ G
~0 ~ of on (~ster, obtainet~ by -~actin- (5-hours heating to reflux temperature) bis-(phthalimido-methyl)-ether and acetic acid anhydride, are dissolved in 500 ml of 2-nitro-propane. 100 g of a macroporous styrene bead polymer crosslinked with 6 % of divinyl benzene (obtained by the bead polymerisation of styrene ~nd divinyl benzene in the presence of 70 %
by ~eight of isododecane, based on the monomer tota]) are s1~ollen in this solution ~ver a period oP 30 minutes.
The reaction mi~ture is heated to 85~, follo~Yed by the drop~ise addition 1~ith stirring of 125 g of concentrated sulphuric acid. After stirring for 16 hours at the same temperature, the resin is separated off and heated to 100C in a~ueous ammonia solution The polymer is then separated off an~ hydrolysed in an autoclave by treatmcnt for lO hollrs ith 40 ~c sodium hydro.-ide solution at a temperature o~ 180C. After the sodium hy~roxide has been washed out, 3~0 ml of a ~eakly basic an~on exchanger are obtained with an acid-binding capacity for N/lO
hydrochloric acid of 2.3 Val/l and a nitrogen content of 10.85 do in the dry material.
By using instead of 125 g of concentrated sulphuric acid, 130 g of water-free phosphoric acid as catalyst ` the same result was achieved.
EX~LE 7 600 g of the ester prepared from N-hydro~methyl phthalimide and acetic acid anhydride are dissolved in 2000 ml o~ dichlorethane. 230 g of a macroporous styrene bead polymer crosslinked with 5 ~ of divinyl benzene (obtained by the bead polymerisation of styrene and divinyl benzene in the presence of 63 ~ by weight of Le A 15 661 - 12 -~.067648 iso~odecane, bnse~ on the total ~eight of the monomers) arc s~ollen in this solution over a period of 30 mimltes at f~ooc. The mixture is then heated to re~lux temper- -ature, follo~ed by the addition l~ith stirring over a r period of 3 hours of 320 g of concentrated sulphuric ~cid. After stirring for 20 hours at reflux temperature, the reaction product is separated o~f and freed from the sl~elling agent adhering to it by suspension in a~ueous ammonia solution, followed by removal of the dichlorethane from the aqueous solution by distillation. The reaction product is separated ofi and subsequently hydrolysed in an autoclave by treatment with 40 ~ sodium hydroxide solution for lO hours at 180C. After the alkali has becn washed out, the yield amounts to lO00 ml. The dry material has & nitrogen content of 12.5 O.
920 ml of the polymer containing aminomethyl groups thus obtained are suspended in 2 litres of water, followed by the addition at 45C first of llO g of concentrated sulphuric acid and then of ?15 ml of 37 ~ aqueous formaldehyde solution and 410 ml of formic acid. The reaction mixture is then slowly heated to 95C and kept at that temperature until the evolution o~ gas is over (approximately 16 hours). The anion exchanger which no~i contains dimethyl aminomethyl groups is separated off, made alkaline with dilute sodium hydroxide and subsequently washed until neutral. The yield comprises llO0 ml.
~; The anion exchanger containing tertiary amino groups thus obtained has an acid-binding capacity for N/lO hydrochloric acid oi 1.9 Val/l. The useful volume capacity (UVC~ in a filter tube in the absence of ~ - 13 -. i .
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~IC~67648 carbon dioxide amounts to 27 8 of CaO/l for a specific load of 30. In the presence of carbon dioxide, the WC
amounts to 42.0 g of CaO/l for a specific load of 10.

354 g of N-hydroxymethyl phthalimide, dissolved in 1200 g of dichlorethane, are heated for 4 hours to reflux temperature with 204 g of acetic acid anhydride. 208 g of a styrene bead polymer crosslinked with 4 % of divinyl benzene are swollen in this ester solution over a period of 1 hour at 60C. ~The mixture is then heated to reflux temperature, followed by the addition with stirring over a period of 1 hour of 196 g of sulphuric acid ~monohydrate).
After stirring for 18 hours at reflux temperature, the reaction mixture is cooled. The polymer is separated off and heated with 1000 ml of 10 % aqueous ammonia solu-tion until the dichlorethane has been completely re ved by azeotropic distillation. The polymer is then hydro-lysed in an autoclave by treatment with 30 % sodium hydroxide for 10 hours at 180C. After the sodium hydro-xide has been washed out, 475 ml of a weakly basic anion , exchanger are obtained with a nitrogen content of 9.3 %
in the dry material and an acid binding capacity for N/10 hydrochloric acid of 3 Val/l.
For conversion into a strongly basic anion ex-changer, the resin is suspended in 1300 g of 15 % aqueous sodium hydroxide solution and the resulting suspension is treated with stirring over a period of 16 hours at 40C -with 410 g of methyl chloride in an autoclave under a pres~
sure of at least 1 atmosphere. After the reaction product has been separated off from the reaction liquid and the ! ~ :
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OH-form has been converted into the chloride form with excess hydrochloric acid, followed by washing out with water, 1230 ml of a strongly basic anion exchanger in the chloride form are obtained with a total capacity of 1.3 Val/l of resin in the chloride form.
By using instead of 196 g of sulphuric acid monohydrate 325 g of iron III chloride ~water-free) as catalyst practically the same result was achieved.

.
531 g of N-hydroxymethyl phthalimide, dissolved in 1760 g of dichlorethane, are heated for 4 hours to reflux temperature with 306 g of acetic acid anhydride.
The ester solution is reacted with 208 g of a styrene bead polymer crosslinked with 4 % of divinyl benzene and further processed in the same way as described in Ex-ample 8. 700 ml of a weakly basic anion exchanger are ` obtained with a nitrogen content of 11 % in the dry material and an acid-binding capacity for N/10 hydro-chloric acid of 3.3 Valfl. After the primary amine has been quaternised with methyl chloride, in the same way as described in Example 8, 1260 ml of a strongly basic anion exchanger in the chloride form are obtained with a totai capacity of 1.58 Val/l of resin in the chloride form.

354 g of N-hydroxy methyl phthalimide, dis-solved in 1200 g of dichlorethane, are heated for 4 hours to reflux te~perature with 260 g of propionic acid anhydride.
; The solution of the resulting propionic acid ester of the N-hydroxymethyl phthali~ide is reacted with 208 g 10~7648 of a styrene bead polymer crosslinked with 4 % of di-vinyl benzene, followed by further processing, in the same way as described in Example 8. 480 ml of a weakly basic anion exchanger are obtained with a nitrogen content of 8 % in the dry material and an acid-binding capacity for N/10 hydrochloric acid of 2.7 Val/l.

The reaction is carried out in the same way as described in Example 10, except that 316.4 g of butyric acid anhydride are used for esterification instead of the propionic acid anhydride. 500 ml of a weakly basic anion exchanger are obtained with a nitrogen content of 7.6 % in the dry material and an acid-binding capacity for N/10 hydrochloric acid of 2.35 Val/l.

354 g of N-hydroxy methyl phthalimide dis-solved in 12Q0 g of dichlorethane are heated for 15 hours to reflux temperature with 9 g of concentrated sulphuric acid to form bis-phthalimido methyl ether. This ether is 2Q heated for 5 hours to reflux temperature with 100 g of succinic acid anhydride to form succinic acid bis-(N-phthaloylamino~-methyl ester which crystallises from the reaction mixture on cooling.
436 g of the succinic acid ester prepared in this manner are dissolved in 1200 g of dichlorethane. 160 g of a macroporous styrene bead polymer crosslinked with 8 % of divinyl benzene Cobtained by bead polymerisation of styrene and divinyl benzene in the presence of 60 ~
by weight of isododecane based on the sum total of mono-

3~ mers~ are swollen in this solution over a period of 30 minutes at 60C, 100 g of concentrated sulphuric acid are then added dropwise with stirring over a period of 3 hours. After stirring the reaction mixture for 20 hours at reflux temperature, the reaction product is separated off. The product is freed form adherent di-chloroethane by suspending it in 10 % aqueous ammonia solution and azeotropic destillation as is described in Example 1. The polymer is then heated for 10 hours to 180C with 40 % sodium hydroxide solution in an autoclave. After the sodium hydroxide has been washed out, 585 ml of ~ weakly basic anion exchanger are ob-tained with an acid binding capacity of 2,72 Val/l for N/10 hydrochloric acid and a nitrogen content of 1Q,9 % in the dry material.

600 g of the ester prepared form N-hydroxymethyl ; phthalimide and acetic acid anhydride are reacted under the conditions applied in Example 7 with 100 g of the macroporous styrene bead polymer crosslinked with 5 % of divinyl benzene described in Example 7.
B After the al~aline hydrolysis of the reaction product there is obtained a weakly basic anion exchanger with an acid binding capacity for N/10 hydrochloric acid of 2,85 Val/l and a nitrogen content of 15,3 %
in the dry material.

600 g of the ester prepared from bis-(phthalimido-methyl)-ether and acetic acid anhydride are reacted under the conditions applied in Example 7 with 100 g of a macroporous styrene bead polymer crosslinked with 3 ,' o~ divinyl benzene (obtained by the bead polymeri-satlon of styrene and divinyl benzene in the presence of Le A 15_661 - 17 -80 ~ by weight of isododecane, based on the monomer total.
After the al~aline hydrolysis of the reaction product there is obtained a weakly basic anion exchanger with a acid binding capacity for N/10 hydrochloric acid of 2,6 Val/l and a nitrogen content of 17,2 % in the dry material.

Le A 15 661 - 18 -

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the production of water-insoluble synthetic resins with anion-exchanger properties by introducing aminoalkyl groups into crosslinked, water-insoluble organic polymers containing aromatic nuclei, wherein the water-insoluble organic polymers con-taining aromatic nuclei are reacted, in the presence of swelling agents for the polymer and in the presence of acid catalysts, with esters N-hydroxyalkylimides, and the acylamino alkylated reaction pro-duct is subsequently hydrolysed in known manner.

2. A process as claimed in Claim 1, wherein the esters of the N-hydroxyalkylimides are used in such a quantity that the molar ratio of ester to aromatic nuclei in the crosslinked polymers is from 0.5 :
1 to 4 : 1.

3. A process as claimed in Claims 1 and 2, wherein esters of N-hydroxyalkylimides with lower aliphatic or aromatic mono or dicar-boxylic or inorganic oxygen-containing acids are used as esters.

4. A process as claimed in Claim 1 or 2, wherein esters of N-hydroxyalkylimides with C2-C3 alkane carboxylic acids are used as esters.

5. A process as claimed in Claim 1 or 2, wherein cyclic N-hydroxymethylimides of aliphatic or aromatic dicarboxylic acids are used as N-hydroxyalkylimides.

6. A process as claimed in Claim 1 or 2, wherein N-hydroxy-methylimides of saturated or unsaturated C4-C6 dicarboxylic acids or of phthalic acid are used as N-hydroxyalkyl imides.

7. A process as claimed in Claim 1 or 2, wherein strong inorganic oxygen-containing acids, optionally in admixture with acetic acid or acetic acid anhydride, are used as acid catalysts.

8. A process as claimed in Claim 1 or 2, wherein sul-phuric acid is used as the acid catalyst.

9. A process as claimed in Claim 1 or 2, wherein from 0.1 to 1.5 mol of catalyst is used per mol of ester.

10. A process as claimed in Claim 1 or 2, wherein the reaction with the esters is carried out at temperatures in the range of from 0 to 150°C.

11. A process as claimed in Claim 1 or 2, wherein a copolymer consisting predominantly of an aromatic monovinyl compound and to a far lesser extent of an aromatic polyvinyl compound acting as crosslinker, is used as the water-insoluble organic polymer containing aromatic nuclei.

12. A process as claimed in Claim 1 or 2, wherein a copolymer of styrene and divinyl benzene is used as the water-insoluble organic polymer containing aromatic nuclei.

13. Aminoalkyl group containing water insoluble synthetic resins with anion exchanger properties con-taining at least two aminoalkyl groups per aromatic nucleus.

14. Water-insoluble at least two aminoalkyl groups per aromatic nucleus containing microporous copolymers with anion exchanger properties of aromatic monovinyl compounds and 0.5 to 7 % by weight, based on the weight of the copolymer, of polyvinyl compounds.

15. The water-insoluble microporous copolymers of claim 14 wherein the aminoalkyl groups are aminomethyl groups.

16. Water-insoluble at least two aminoalkyl groups per aromatic nucleus containing macroporous copolymers with anion exchanger properties of aromatic mono-vinyl compounds and 2 to 10 % by weight, based on the weight of the copolymer of polyvinyl compounds, the porosity of said copolymers resulting from polymerisation in the presence of 40 to 100 % by weight based on the weight of the monomers of an inert organic liquid.

17. The water-insoluble macroporous copolymers of claim 16 wherein the aminoalkyl groups are aminomethyl groups.

18. A method of filtering cigarette smoke which comprises using as filter materials in filters of cigarettes at least two amino alkyl groups per aromatic nucleus containing water-insoluble resins according to any of claims 13, 14 or 16.