DD156978A5 - ANION EXCHANGERS, METHOD FOR THEIR PRODUCTION AND THEIR USE - Google Patents

Abstract

The invention relates to anion exchangers, processes for their preparation and their use, preferably in the water treatment technology. The aim of the invention is the provision of anion exchangers with a significantly improved usable capacity for weak acids. According to the invention, anion exchangers based on crosslinked N-alkylated polyacrylic or polymethacrylamides are provided which have both weakly basic amino groups and also quaternary ammonium groups. In particular, the proportion of quaternary ammonium groups is 10 to 80%, preferably 15 to 65% of the total basic groups of the anion exchanger. For the preparation, the weakly basic amino groups are partially quaternized in anion exchangers based on crosslinked N-alkylated polyacrylic or polymethacrylamides by processes known per se.

Description

58 472/12

AP C08P / 226 885/6

Anion exchangers, process for their preparation and their use '.

Field of application of the invention

The invention relates to an anion exchanger based on crosslinked IT-alkylated polyacrylic or polymethacrylamides, a process for their preparation and their use.

The anion exchangers according to the invention are used in particular in water treatment technology.

Characteristic of the known technical solutions

In the water treatment technology for the adsorption of weak acids, especially of silica and its salts, strong base anion exchangers are used hitherto; h _e anion, the quaternary ammonium groups almost exclusively given by The performance of this anion exchanger is by their Usable Capacity (EK) in d _s h _c by its adsorption capacity for silicic acid under practical conditions · the useful Ka. The capacity of the anion exchanger is determined primarily by its content of strongly basic groups per unit volume and its regenerability after loading. In addition, the concentrations and proportions of the substances (ions) dissolved in the water are known under practical conditions for the performance of the anion exchange resins / erer composition, determining, and also the applied process engineering (see * Ulimann's Encyclopedia of techni-. See Chemistry, 4 »Edition, 1977, Volume 13, pages 315 - 33O) ₀ This applies both to the usable capacity of strongly basic anion exchangers of polystyrene Type that is still the most common today

be used for the removal of weak acids, as well as for the less common strong base anion exchanger based on crosslinked N-alkylated polyacrylamides (polyacrylamide type).

However, the useful capacity of these known strongly basic anion exchangers with exclusively quaternary ammonium groups for weak acids is technically unsatisfactory. It has therefore tried this unsatisfactory performance through an improved process technology

Balance 1P. However, this requires a higher technical effort (see Ulimann's Encyclopedia of Industrial Chemistry, Ic.).

In addition, one has for the adsorption of weak acids partially quaternized anion exchanger of

Polystyrene type proposed (see, for example, DE-OS 28 02 642). These partially quenched polystyrene-type anion exchangers contain both strongly basic, i. quaternary ammonium groups, as well as weakly basic, tertiary amino groups. Although these polystyrene-type partially quenched anion exchangers often have higher usable capacities and a better utilization of the regenerating agent than the known strongly basic anion exchangers under comparable conditions; nevertheless they do not have

2 5 led to a general performance improvement

and therefore far no widespread application in water treatment technology found. In the deacidification of waters containing predominantly weak acids (for example when used in combination with strong

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acidic cation exchangers and weakly basic anion exchangers), they have even lower usable capacities than the fully quaternized strongly basic anion exchangers *

• Object of the invention

The aim of the invention is to provide anion exchangers having a significantly improved useful capacity for weak acids, the useful capacity of which is substantially higher than that of fully-quaternized strongly basic anion exchangers even in the deacidification of waters containing only weak acids. "

Presentation of the ₁ essence of the invention

The object of the invention is to quaternize a certain part of the amino groups in weakly basic anion exchange units based on crosslinked IT-alkylated polyacrylic or polymethacrylamides ₆

The invention therefore relates to anion exchangers based on crosslinked N-alkylated polyacrylic or polymethacrylamides, which are characterized in that they have both weakly basic amino and quaternary ammonium groups.

Such anion exchangers based on crosslinked N- »alkylated polyacrylic or polymethacrylamides in which the proportion of quaternary ammonium groups is from 10 to 80%, preferably from 15 to 65 %, of the basic groups contained in the anion exchanger have proven particularly suitable»

The anion exchangers according to the invention: have a much larger adsorption under practical conditions. for weak acids, in particular for silicic acid, than the known fully-quaternized and

partially quaternized anion exchanger. Among weak acids bound by the anion exchangers of the present invention are both weak inorganic acids such as silica and carbonic acid, as well as organic acids such as carboxylic acids, e.g. Formic acid, acetic acid, citric acid, benzoic acid, furthermore phenols and humic acids to understand.

In addition, the anion exchangers of the invention are easier and more completely regenerable than the known anion exchangers. Also absorbed from the water organic substances are easier and practically completely released again when regenerating with sodium hydroxide, so that no contamination of the Ahionenaustauscher by these substances occurs.

In the deacidification of waters containing only weak acids, the useful capacity of the anion exchanger according to the invention is substantially greater than that of the known strongly basic anion exchangers.

In comparative experiments with de-aerated and degassed water, the anion exchangers according to the invention showed values of usable capacity up to 150% higher than the starch-based, completely quaternized anion exchangers of polystyrene and polyacrylamide.

25 type and up to 50% higher usable capacity

as the partially quaternized polystyrene-type anion exchangers. With the increase in useful capacity

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In addition, there is a drastic reduction in the regenerant requirement (caustic soda) associated with about 250% of the theory for fully quaternized anion exchange resins, about 150% for partially quaternized anion exchange resins of polystyrene Τγρ to 105 to 110% of theory for the anion exchangers according to the invention.

An increase in the usable capacity and decrease in the regenerant requirement occurs not only in the deacidification of deaerated and degassed water, but also in the deacidification of only de-aerated water and water containing only weak acids.

The above-described advantageous properties of the anion exchangers according to the invention are so surprising because it is known that both the fully quaternized strong base and the weakly basic, polyacrylamide-type anion exchangers containing tertiary amino groups have no substantially greater useful capacity than the comparable polystyrene-type anion exchangers ,

The aforementioned advantageous properties of the anion exchangers according to the invention are also independent of the ion exchange process in which they are used, e.g. whether they are used in DC or countercurrent processes. The application of the anion exchangers according to the invention from poly-

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The acrylamide type in desalination plants offers the following economic advantages: The higher usable capacity makes it possible to save on the amount of resin and on the equipment at the same time as the plant's capacity is comparable. In addition, significant cost savings are achieved due to the lower Regeniermittelbedarfes. The useful capacity of the anion exchanger according to the invention is also largely independent of the specific load.

In this respect, too, they differ favorably from the known anion exchangers. Compared with the known, fully quaternized strong base anion exchangers, they also have the advantage that they during loading or during regeneration

15 show virtually no volume change, this is

aerodynamically advantageous, also the osmotic-mechanical stress of the exchange grains is reduced during operation in an advantageous manner.

The preparation of the anion exchangers according to the invention can be carried out by known processes, for example by the process described in US Pat. No. 2,675,359. According to this process, crosslinked acrylic ester or methacrylic ester resins are converted into polyacrylamide-type resins by aminolysis with polyamines containing at least one primary amino group. Such polyacrylamide resins contain, depending on the type of polyamine used and the reaction, primary, secondary and / or tertiary amino groups. They represent weakly basic

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Anionenaustauschharze represents "By exhaustive quaternization with alkylating agents such as methyl chloride strong base anion exchangers are prepared with quaternary ammonium groups." Strong polyacrylamide-type anion exchanger with macroporous structure are described in US-PS 37 91 866. GB-PS 11 13 149 describes the preparation using certain crosslinking agents prepared gelatinous and macroporous anion exchanger based on crosslinked polyacrylic acid amides »

The preparation of the anion exchanger according to the invention proceeds via 3 stages. In the first step, a beaded, crosslinked (meth) acrylic acid ester resin is prepared in a known manner by copolymerization of a lower acrylic or methacrylic acid alkyl ester with at least one crosslinking agent. "Particularly suitable esters are the methyl acrylate and ethyl ester. *** Suitable crosslinking agents are ζ. "Divinylbenzene, divinyltoluene, divinylnaphthalene, divinylethylbenzene, N, I'-methylene diacrylamide, 11, H" ^{1 "} -methylenedimethacrylamide, ^, K'-ethylenediacrylamide, trivinylbenzene, trivinylnaphthalene, polyvinyl ethers of polyols such as ethylene glycol, glycerol, pentaerythritol, aliphatic and cycloaliphatic hydrocarbons having at least two Ally! groupings such as hexadiene (1.5) »Dimethylhexadien- (1.5), 0ctadien- (1.7), ^f frivinylcyclohexan. Have proven particularly useful as a crosslinking agent * ' ^?

Divinylbenzene and mixtures of divinylbenzene and aliphatic hydrocarbons having at least two allyl moieties or polyol polyvinyl ethers. Divinylbenzene is advantageously used in an amount of 2 to 20 wt .-%, said aliphatic hydrocarbons or Polyolpolyvinylether advantageously in an amount of 2 to wt .-%, based on the total amount of the monomers. ,

The crosslinked (meth) acrylic ester resins can be prepared as gel or macroporous resins. Macroporous resins are obtained when the perpolymerization, e.g. in the presence of organic solvents, in which the monomers dissolve, but the polymer is insoluble and is not or hardly swellable. Such organic solvents are, for example, aliphatic hydrocarbons, alcohols, esters, ethers, ketones, trialkylamines, nitro compounds. They are usually used in an amount of up to 100% by weight, based on the total weight of the monomers.

The copolymerization is, for example, azo-bis-isobutyronitrile usually carried out by the suspension polymerization in the presence of a radical initiator such as benzoyl peroxide or an azo compound, in the temperature range of 20-120 ⁰ C and using conventional suspension stabilizers.

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In the 2-stage reaction, the ester resin is amino-lyzed with polyamines containing at least one primary amino group. Suitable amines include: polyalkylenepolyamines such as diethylenetriamine dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, oxyethyl-diethylenetriamine, IT-aminoethylmorpholine, Ιϊ, Ν-dimethylethylenediamine, U , N-dimethylpropylenediamine ~ (1,3) »N, N-diethylpropylenediamine-C1,3) · ϊΤ, Η-dimethylpropylenediamine ~ (1,3) has proven to be particularly suitable«

In the reaction stage, the amino groups of the N-aminoalkylated poly (meth) acrylamide resin formed are partially quaternized with suitable alkylating agents. For this purpose, known alkylating agents such as dialkyl sulfates, alkylene oxides, halohydrins, epihalohydrins and "" or all Alky! Halides such as methyl, Bthyl - or Propylchlorid be applied «

The invention is explained in more detail below with reference to some examples

Examples 1 - 5

1000 ml each of the weakly basic anion exchanger (tertiary amino group content: 1.69 mol / l), whose preparation is described below, are suspended in 1 of demineralized water. After adding equimolar amounts of sodium hydroxide solution (based on the methyl chloride to be introduced) to the individual exchanger samples, methyl chloride is introduced into the suspensions at room temperature. Subsequently, the individual reaction mixtures are acidified by the addition of hydrochloric acid until the suspensions have a pH of 2. In this way, the partially quaternized anion exchangers are completely converted into their salt form. After separating the anion exchanger from its reaction

¹ ^ tionsiösungen v / Ground washed in the filter tube with 5 1 deionized water.

In Table 1 below, the amounts of methyl chloride used for the individual batches, the time used for introducing the methyl chloride, the amounts of sodium hydroxide used, the yields of partially quaternized anion exchange resins, the total content of strongly basic and weakly basic groups in mmol / ml exchanger (Total capacity: TK), the content of strongly basic groups in mmol / ml and in% of the TK (content of strongly basic groups in% of the TK = degree of quaternization) as well as the volume change

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in% in the regeneration of the exchanger loaded with hydrochloric acid by sodium hydroxide solution (5%).

The weakly basic anion exchanger used was obtained as follows.

a) Preparation of macroporous Acryisäureester bead polymer.

In a mixture of 4007 g of methyl acrylate, 358 g of technical grade divinylbenzene (content of pure divinylbenzene: 62.8% by weight, residual ethylstyrene) and 138 g of octadiene (1.7), 225 g of isododecane and 30 g of dibenzoyl peroxide (75%) were added. ig) solved. The mixture was then stirred into an aqueous solution of 6.75 g of methyl cellulose and 0.225 g of sodium nitrite in 4500 g of water and first for 5 hours at 65 ⁰ C, then perlpolymerisiert 2 hours at 90 ⁰ C.

Yield: 4297 g bead polymer (dry); Grain diameter: 0.1 to 1.0 mm.

b) Aminolysis of the Macroporous Acrylic Ester Bead Polymer

250 g of the bead polymer obtained according to a) were heated with 1200, g of,, Ν-dimethyl-propylenediamine (1.3) for 5 hours at 195 to 200 ⁰ C. The macroporous, weakly basic anion formed then wurde- from ^excess: amine separated and washed to neutrality in the filter tube with deionized water. ι.

Yield: 1250 ml of anion exchanger;

Content of weakly basic groups: 1.69 mmol / 1.

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tr ¹ (B table 1 Introduction time ZT h J NaOH CgJ 3 Yield CmIJ TK / jmiol / m \ 7 strong basic groups Zmmol / ml7 3 d , TK / Volume change during regeneration C% J 19,967 3 8th, 6 1 1, 0.14 10 - 10 In game Methyl chloride ζ. gj 6 16 9 1 1, 0.25. 18. - 3 1 10.5 9 26 1 1 1, 0.49 36 + 2 2 · 21 16 45, 4 1 1, 0.79 59 + 9 3 34 20 57 1 , 1, 1.0 74 + 11 · " 4 57 .240 , 36 5 72.5 .240 , 36 .250 35 .255 , 34 .255 35

Example 6

1 1 of a gelled, weakly basic anion exchanger (tertiary amino group content 1.88 mol / l), prepared by aminolysis of 250 g of an acrylate ester bead polymer of ethyl acrylate, 5% divinylbenzene and 3% 1,2,4-trivinylcyclohexane at 1,200 g N, N-dimethylpropylenediamine (1.3) according to Example 1b is mixed under the conditions described in Examples 1 to 5 with 38 g of methyl chloride.

TO quaternized.

Yield: 1.22 1 anion exchanger;

Content of strongly basic groups: 0.54 mmol / ml = 33%

the TC; 'Content of weakly basic groups: 1.09 mmol / ml; Volume change during regeneration with caustic soda solution: none.

Example 7

1 l of a macroporous, weakly basic anion exchanger (tertiary amino group content of 1.35 mol / l), prepared by aminolysis of 250 g of an acrylic acid ester resin obtained by bead polymerization of 2,001 g of methyl acrylate, 181.5 g of technical grade divinylbenzene (divinylbenzene content: 62, 1%) and 67.5 g of hexadiene (1.5) in the presence of 450 g of isododecane, with 1 500 g of N, N-diethy! Propylenediamine (1.3) according to Example 1b under the in Example 1 to 5 described conditions with 36.6 g of ethyl chloride partially quaternized.

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Yield: 1.3 1 anion exchanger; Content of strongly basic groups: 0.39 mmol / ml =

35% of the TC;

Content of weakly basic groups: 0.72 mmol / ml; Volume increase on regeneration with caustic soda solution; 2%.

Example 8

1 1 of a macroporous weakly basic ^anion: exchanger (tertiary amino group content 1,85 mol / lj prepared by aminolysis of 250 g of an acrylic acid

Ethyl ester resin obtained by bead polymerisation of 3,890 g of methyl acrylate and 610 g of technical grade divinylbenzene (divinylbenzoyl content: 59%) in countervail of 450 g of white spirit, with 1,200 g of N, N-dimethylpropylenediamine (1,3) according to

The solution 1b is suspended in 1 l of demineralized water and, after addition of 30 g of NaOH (as a 45% strength aqueous solution) under the conditions described in Examples 1 to 5, with 37 _? 5 g of methyl chloride quaternized. Yield: 1.220 1 anion exchanger;

20 content of strongly basic groups: 0.5 mmol / ml =

33% of the TC;

Content of weakly basic groups: 1.0 mmol / ml; Volume increase on regeneration with caustic soda: 1 -% · -

Example 9

210 ml of a macroporous, weakly basic anion exchanger (tertiary amino group content 1.76 mol / l), prepared by aminolysis of 86 g of a

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AS

Methacrylsäureesterharzes, which had been obtained by bead polymerization of 889.5 g of methyl methacrylate, 80.5 g of technical divinylbenzene (Divinylbenzoylgehalt: 62%) and 30 g of octadiene (1.7) in the presence of 100 g of isododecane, with 415 g of Ν, Ν '-Dimethy! Propylenediamine (1.3) at 245 ⁰ C in 10 hours, are suspended in 200 ml of deionized water and after the addition of 20 g of methyl chloride in 20 hours at 40 ⁰ C partially quaternized. The workup was as in

10 Example 1 to 5 described.

Yield: 315 ml of anion exchanger;

Content of strongly basic groups: 0.32 mmol / ml =

30% of the TK; Content of weakly basic groups: 0.74 mmol / ml; Volume increase on regeneration with caustic soda: 2%.

Comparative Examples A to E

Preparation of polystyrene-type anion exchangers with strong base quaternary ammonium groups and weakly basic tertiary amino groups.

Samples of a commercial, macroporous weakly basic anion exchanger with tertiary amino groups, prepared according to the specifications of DE-PS 24 18 976 aus.einem with 6% divinylbenzene crosslinked and made with the addition of 70% isododecane porous styrene bead polymer, were under the in Example 1 partially quaternized with methyl chloride until 5 described conditions. In each case, a 10% excess of methyl chloride, based on the desired Quaternierungsgrad applied.

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-yl

The content of strongly basic groups in mmol / ml of the partially quaternized anion exchangers and in% of their total content of strongly basic and weakly basic groups (% of the total capacity TK) was:

Comparative example strong basic groups Zmmol / ml7 / T% of TKj

A 0.23 17

B 0.31 23

C 0.48 35

D 0.78 58

E. 1.29 97

Example 10

1 l each of the anion exchangers described in Examples 1 to 5 and Comparative Examples A to E in the filter tube (internal diameter 55 mm) several times with entbastem'ent degassed and tap water at a specific load of 20 1 of water per 1 resin per hour until the silica breakthrough ( 0.1 mg / 1 SiO in the filter process) and then regenerated with 40 g of NaOH (as a 4% aqueous solution) at 20 ⁰ C in countercurrent at a specific load of 2 1 per 1 resin per hour. -

Analytical values of degassed and degassed water: strong acids (total): 7 mmol / 1 weak acids (total): 0.5 mmol / 1

20 silica (as SiO-): 7 mg / l

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Table 2 shows the useful capacity (NK) and regenerant utilization (regenerant amount in mol% of NK) values obtained for the individual anion exchangers. The values given are mean values from at least 3 filter runs.

Table 2

Anionic strongly basic exchanger groups

Zmol / 37 /% d.

NK regenerating agent

ZmoUl / amount

£ mole% of NK7

example 0.14 10 1 0.25 18 2 0.49 36 3 0.79 59 4 1.0 74   5. example 0.23 17 A 0.31 23 B 0.48 35 C 0.78 58 D 1, 29 97 e

0.67 0.92 0.95 0.76 0.66

0.63 0.62 0.60 0.57 0.38

149 109 105 132 152

159 161 167 175 263

From Table 2 it can be seen that the usable capacity (NK) of the polyacrylamide-type exchangers according to the invention is always greater than the comparable ones

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26 8 85 6

Exchangers of polystyrene type (comparable are exchangers whose content of strong basic groups is about the same size).

The highest NK values are exhibited by the anion exchangers according to the invention whose content of strongly basic groups ranges from 15 to 65% of the total capacity (TK) (see Examples 2 and 3). These values are about 50% higher than the NK values of the comparable anion exchangers A and C of the polystyrene TO type and nearly 150% higher than the NK value of a macroporous, strongly basic anion exchange resin (Comparative Example E).

In addition, it is apparent from Table 2 that the utilization of the amount of regenerant used in the polyacrylamide type anion exchangers according to the present invention is substantially better than in the polystyrene type control resins: in the anion exchange resins of the present invention having the highest NK values, Examples 2 and 3, the regenerant excess was only 9 or 5%, based on the useful capacity found, under the experimental conditions, whereas it was about 60% in the best comparative resins.

Example 11

Under the conditions described in Example 10, 1 l each of the anion exchanger described in Example 3 and that described in Comparative Example C are repeatedly countercurrently charged and regenerated. The loadings are carried out with three different waters; in fact

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1. with immersed water and deionized water (tap water which had been degased by treatment with a strongly acidic cation exchanger and degassed by passing it over a carbon dioxide gasifier); Water content of weak acids (carbonic acid + silica): 7 mol%, based on the total content of weak and strong acids;

2. with deionized water (tap water which had been degased by treatment with a strong acid cation exchanger); Content of weak acids (carbonic acid + silicic acid): 31 mol%, based on the total content (of weak and strong) acids;

3. with deionized water (tap water that had been desalted by treatment with strong acid and weakly basic ion exchangers); Content of weak acids: 100 mol%.

Table 3 summarizes the useful capacity (NK) and regenerant utilization (regenerant amount in mol% of NK) values obtained for the two anion exchangers using the different water. The values given are mean values from at least 3 filter runs.

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Table 3

Content of the water to be treated

^ Strong-basic exchanger groups _ ^ / mol / l_7 Z% d. TK / s acids acid weak acids

Irmol / Xj / V / mmol / l7

KK "'-' '' ^ 'Regener iermittelmenae / rnol / 17% of NK /.

according to example

7 , 0 93 O, 5 7 0 95 105 7 , 9 69 3, 6 31 0 ' ⁸ 125 O 0 4, 8th 100 0 , 73 137 *

3 0.49

(D) (3)

Vergl.-

Example C c-, 48 Π)

  (2) (3)

* In this experiment, 2% sodium hydroxide solution was used, otherwise silica precipitation occurs.

7 , 0 93 0 , 5 7 0 , 6 167 7 , 9 69 3 , 6 31 0 , 5 200 0 0 4 ,8th 100 0 3 330

As can be seen from "Table 3, the polyacrylamide-type anion exchanger according to the invention has significantly higher NK values than the anion exchanger of the polystyrene type (Comparative Example C) for Example 3. For waters with a content of weak acids of 7 and 7, respectively 3% molar%, based on the total content of strong and weak acids, are found to be about 60% higher NK values, and if the water contained only carbonic acid and silica (proportion of weak acids = 100 mol%), the NK values Values of the anion exchange resin according to the invention about 150% higher than that of the comparative resin.

It is also apparent from Table 3 that the utilization of the amount of regenerant used in all three cases in the anion exchange resin according to the invention is much better than in the case of the polystyrene-type comparative resin. Thus, the regenerant excess in the anion exchanger according to Example 3, depending on the experimental conditions 5 to 37%, based on the found NK value, in the comparative resin C 67 to 230%.

Example 12

Each 1 1 of the anion exchangers described in Example 3 and Comparative Examples C and E 'in the filter tube (inner diameter 55 mm \ several times with degassed and degassed tap water at a specific load of 20 1 of water per 1 resin per hour until the silica breakthrough (0.1 mg / 1 SiO in the filter process) and then with 80 g of NaOH (as 4% aqueous

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Solution) at 20 ⁰ C in cocurrent at a specific load of 5 1 per 1 resin per hour regenerated. Content of degassed and degassed water on weak acids 7 mol%, based on the total content of weak and strong acids. ·

Table 4 lists the useful capacity (NK) and regenerant utilization (replenisher amount in mol%: NK) obtained for the individual anion exchangers. The values given are mean values from at least 3 filter runs.

Table 4 '

Anions- strongly basic NK Regenerating agent exchanger G_ruppen / mol / l / amount

d. TK7 ZJSol% of NS7

example 3 O , 49 36 0 96 208 example C 0 48 35 0 , 68 294 example e 1 , 29 97 0 45 444

From Table 4 it can be seen that the inventive. Anion exchangers offer significant benefits in terms of usable capacity (NK) and regenerant consumption even in the conventional DC procedure. With 30% or 50% less regenerant consumption, they have a usable capacity increased by 30% and 50%, respectively. , ·

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* 3

-, 24 -

Example 13

1 l each of the ion exchange resins described in Example 3 and Comparative Example E are rinsed into a glass column (internal diameter: 70 mm) and regenerated with 100 g NaOH (as 4% aqueous solution) / asser washed out.

The thus prepared anion exchangers are at a specific load of 10 1 solution per liter of resin and per hour with an aqueous acetic acid solution containing in liter of 900 mg (= 15 mmol) of acetic acid loaded until the concentration of acetic acid in the filter effluent to 90 mg / l, ie increased to 10 % of the acetic acid concentration of the original solution.

Up to this breakthrough point, the following amounts of solution were filtered through the resins or the following amounts of acetic acid were taken up:

Anion exchanger according to Example 3 Comparative Example E

Liter of solution 69.9 36.9

Acetic acid Cgl 62.9 33.2

Usable capacity

[mol / 1 resin] 1.048 0.553

Until about 93% loading of the two resins, the residual content of Essigaäure in the filtration process was less than 3 mg / 1.

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Example 14 . '

In 3 glass columns a ^, b. , c. are each 1 1 of the anion exchange resin described in Example 3 and in • 3 glass columns a ~, bp, Cp each 11 of the anion exchange resin described in Comparative Example E rinsed (internal diameter of the glass columns: 70 mm). Each of the columns filled with 1 liter of resin is regenerated with 100 g of NaOH (as a 4% aqueous solution). The regenerant excess is washed from each column with 4 1 of deionized water.

The thus prepared anion exchangers are loaded at a specific load of 10 1 solution per 1 resin and per hour with the aqueous solutions described below (working direction: from top to bottom) until the conductivity in the filter outlet has risen to 50, μS / cm. The amount of solution that can be filtered through this column until it breaks through each of the columns is measured. , From this amount, the usable capacity of the anion exchanger located in the column results.

20 The following solutions were used for loading:

A for loading the columns a. * And a ₂ an aqueous acetic acid solution, content of H ions: 14.6 mmol / l; Conductivity: 185 pS / cm;

B in the columns b. and bp an aqueous benzoic acid solution (content of H ions: 14.95 mmol / l;

290 / μS / cm);

C for loading the columns c, and Cp for an aqueous molasses solution degummed by prior treatment with a cation exchanger (content of H ions: 15.2 mmol / l, conductivity: 176 pS / cm, extinction E (at 420 nm; Layer thickness: 10 cm) ~ 8.4).

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In Table 5 below, the amounts of solution that could be filtered through the individual columns to the breakthrough track and the useful capacities of the anion exchangers calculated from these amounts of solution (the values indicated are in the middle of the liter) are shown 5 consecutive working cycles (duty cycle: loading, regeneration, washing out))

Table 5

A column ^a 1 ^a 2 52 B column ^b 1 ^b 2 C column 30 Liter of solution 72 0.76 68 42 48 0.46 Usable capacity / mo1 / 1 resin_7 1.05 - 1.02 0.63 0.73 96 Decolorization of the solution J_% J _ - 97

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Claims (3)

Claim of invention. 1 »Process for the preparation of anion exchangers based on crosslinked N-alkylated polyacrylic or polymethacrylamides, characterized in that the
weakly basic amino groups in anion exchangers based on offset N-alkylated polyacrylic or
Polymethacrylamides according to known methods
with partially quaternized alkylating agents "having 1 to 3 C atoms" 2 «method according to item 1, characterized in that 10 to 80 % of the weakly basic amino groups in. the anion exchangers based on crosslinked H-alkylated polyacrylic or polymethacrylamides quaternized according to methods known per se. 3 «method according to item 1, characterized in that one 15 to 65 % der.schY / achbasischen amino groups in the anion exchangers based on crosslinked H-Alkylier ~ ter polyacrylic or polymethacrylamides by itself
quaternized with known methods