CS255497B1 - Amphoteric resin containing pyridinebetaine groups - Google Patents

Abstract

Amphoteric resin containing pyridinebetaine groups are suitable as for ion exchange as well as sorption desorption of substances. Prepared from copolymer 2-vinylpyridine and / or 4-vinylpyridine and / or their methyl or ethylhomologists with monomers from the group comprising divinylbenzene, divinylpyridine and glycol dimethacrylate, optionally with styrene, vinyl acetate or with alkyl esters of the acid acrylic and methacrylic carbon of the atoms in the alkyl group of 1 to 8, respectively by reacting said copolymer with an acid chloroacetic acid or its sodium, potassium or an ammonium salt in an aqueous medium at a temperature of 5 to 90 ° C in a molar ratio pyridine nitrogen in copolymer and acid chloroacetic acid or its salts 1: 0.5 to 1: 1.5.

Description

The invention relates to a new type of resin useful both for ion exchange and for sorption and desorption of substances.

Copolymer prepared by copolymerization of 2-vinylpyridine or 4-vinylpyridine or their homologues, or mixtures thereof with divinylic monomers such as divinylbenzene, divinylpyridine or glycoldimethacrylate, or else using other monomers such as styrene, vinyl acetate, acrylic or methacrylic acid esters, acrylonitrile and the like can serve as a weakly basic anionic functionalized pyridine or after alkylation (quaternization) of nitrogen by reaction with an alkylating agent such as methyl iodide (U.S. Pat. Nos. 2,801,223, 2,801,224 and 2,540,985, U.S. Pat. NSR No. 2,164,261, GDR Pat. No. 16,075), methyl bromide (Japanese Pat. No. 77,123,412, Science 108, 545 (1948)), benzyl chloride (Japanese Pat. No. 77,123,412) dimethylsulfate (U.S. Pat. Nos. 2,828,270 and 2,540,985), methyl p-toluenesulfonate (U.S. Pat. No. 2,484,430), glycerol mono- and dichlorohydrin (U.S. Pat. No. 910,665), dimethylamine and the like. dimethylamine hydrochloride in formaldehyde solution (U.S. Pat 01 223 and 2 801 224, U.S. Pat.

USSR No. 679,590), as an anion exchange resin with a strongly basic pyridinium group. In all these cases, a substantially intermediate anion exchange resin is obtained in which the quaternary nitrogen constitutes about half of the total nitrogen in the resin.

It has now been found that amphoteric resins containing pyridine betaine groups can be prepared from a copolymer of 2-vinylpyridine and / or 4-vinylpyridine and / or their methyl or ethyl homologues with monomers from the group comprising divinylbenzene, divinylpyridine and glycol dimethacrylate and optionally with styrene, vinyl acetate or alkyl esters. These resins are the object of the present invention, characterized in that the resins are prepared by reacting said copolymer with chloroacetic acid or its sodium, potassium or ammonium salt in an aqueous medium. at a temperature of 5 to 90 ° C in a molar ratio of pyridine nitrogen in the copolymer to chloroacetic acid or their named salts of 1: 0.5 to 1: 1.5.

The resulting amphoteric resin contains a carboxymethylpyridinium functional group, which is known as pyridine betaine in monomolecular chemistry. This group contains at the same time a strongly basic pyridinium nitrogen and a weakly acidic carboxyl group linked through a methylene group. Both groups interact, the quaternary nitrogen as a strongly electronegative enhances the acidity of the carboxyl group, and the carboxyl group weakens the basicity of the quaternary nitrogen by electron transfer. Thus, in the neutral environment of an aqueous solution, a functional group of this type in the form of an inner salt may be expected.

The amphoteric resins according to the invention are capable of absorbing both anions and cations, both acids and hydroxides, and their sorption capacity depends on the concentration of salt, acid or hydroxide in the surrounding solution:

CH- NaOH

CH.

CH 13 I ⁽ Na ²⁺⁾

C = 0

OH

C = O

C = O

CH

The resins have considerable swellability because the nitrogen substitution reaches a high degree, more than 80% of the theory and the conversion can be easily monitored from increment; Cl ions in the reaction mixture. However, the swellability can be controlled by the content of the crosslinking agent in the mixture of copolymerizing monomers.

Because of their amphoteric nature and good swelling capability, these resins are capable of operating as a retarding ion exchange resin, causing different retardations depending on the affinity to different cations and anions as the solutions flow through the resin bed and thereby separate or dissociate dissociated and undissociated solution components. They can also be advantageously used as adsorption resins, for example for decolourising or clarifying solutions or as fillers for the preparation of heterogeneous ion exchange membranes, optionally for the preparation of homogeneous membranes for dialysis, inverse osmosis and the like.

The invention is illustrated by the following examples.

Example 1

A pearl copolymer is prepared by suspension copolymerization of 43.4 g of 2-vinylpyridine, 4.1 g of divinylbenzene and 2.0 g of ethylvinylbenzene in an aqueous 1% starch wax solution, initiating 2 wt. % monomers of azobisisobutyronitrile and 1 wt. benzoyl peroxide. 84 ml or 62 g of wet suction copolymer is obtained. Wash well with water and the aspirated copolymer is mixed with an aqueous solution of 39 g of chloroacetic acid in 230 ml of water, carefully and neutralized with 16.5 g of NaOH while cooling. The suspension is heated to 80 ° C with stirring for 15 h. The volume of the resin, i.e. the solid, non-cracked beads of about 0.4 to 1.0 mm in diameter, is thereby increased to 190 ml. The suctioned, wet product weighs 142 g.

According to the Cl content of the mother liquor, the conversion was 96.1% of the theory, according to the weight gain of the resin after the reaction was 78.2% of the theory. The swelling is 72.7% moisture;

g of dry resin absorbs 2.66 g of water and increases to 6.1 ml.

Exchange capacity depending on the concentration of NH 4 Cl solution in solution in equilibrium with resin:

Concentration of solution NH 4 Cl (wt.%) H ₂ O eluate Meq / ml eluate 4% Na ₂ SO ₄ Total 5 0.03 0.04 0.07 10 0.21 0.51 0.72 20 May 0.41 0.76 1.17 30 0.46 0.82 1,28

Assay Method: 4 ml of resin washed with distilled water until the Cl ion disappeared in the eluate were washed in a 250 ml NH 4 Cl solution column. The ion exchanger was then washed with methanol until the Cl ion disappeared in the eluate. The resin was further washed with distilled water and the filtrate was collected in a 250 mL volumetric flask. The last fractions of eluate were free of Cl ions. This was followed by elution of the resin with 250 mL of a 4% Na ₂ SO 4 solution into a 250 mL volumetric flask. The last portions of sulphate eluate did not contain Cl ^- ions. The content of Cl ions in both eluates was determined in an aliquot after acidification with a few drops of conc. HNO 4 by potentiometric titration of 0.1 N AgNO 4.

EXAMPLE 2 g of a copolymer prepared by suspension copolymerization of 70 g of 2-vinylpyridine, 70 g of 4-vinylpyridine, 12.5 g of glycol dimethacrylate, 5 g of styrene and 5 g of glycol methacrylate are preheated in water with a solution of 27 g of chloroacetic acid in 250 ml of water. , adjusted to pH 7.5 by careful neutralization with 5% aqueous ammonia for 8 h at 70 ° C and an additional 2 h at 90 ° C. After cooling, the resin was thoroughly washed with water.

The product exhibits a swellability of 74% moisture and an overall sorption capability at equilibrium with a 30% NH 4 Cl solution of 1.35 meq / ml.

Example 3 g of a suspension copolymer prepared by copolymerization of 139 g of 4-vinylpyridine, 15 g of divinylpyridine, 10 g of vinyl acetate, 5 g of methyl methacrylate and 5 g of ethyl acrylate are reacted with 225 g of an aqueous solution of 36 g of chloroacetic acid at 5 ° C for 1 h. The mixture was then heated with stirring at 60 ° C for 2 hours and at 80 ° C for a further 4 hours. Finally, the mixture is cooled to 30 ° C and 50 g of an aqueous solution of 15.2 g of NaOH are added and stirred with heating at 90 ° C for another 4 h.

The product has a content of 59.9% by weight. moisture and sorption capacity at equilibrium with 30% aqueous NH ₄ Cl solution 1.22 meq / ml.

Example 4

A mixture of 70 g of 2-methyl-4-vinylpyridine, 70 g of 2-vinyl-4-methylpyridine, 17.2 g of 2,4-divinylpyridine and 15 g of glycoacrylate is poured after dissolving 3 g of azobisisobutyronitrile to the level of 20% aqueous NaCl solution. The resulting 1.2 mm film is carefully washed and immersed in a solution of 170 g of sodium chloroacetate in 600 ml of water at room temperature, i.e. about 20 to 22 ° C. for 15 days. A sample of the prepared resin has a moisture content of 68.7% by weight. and a total sorption capacity in equilibrium with a 30% NHCl solution of 1.18 meq / ml.

OBJECT OF THE INVENTION

Claims (1)

OBJECT OF THE INVENTION Amphoteric resins containing pyridine betaine groups based on a copolymer of 2-vinylpyridine and / or 4-vinylpyridine and / or their methyl or ethyl homologues with monomers selected from the group consisting of divinylbenzene, divinylpyridine and glycol dimethacrylate and optionally styrene, vinyl acetate or alkyl esters of acrylic acid and methacrylic acid carbon atoms in an alkyl group of 1 to 8, obtainable by reacting this copolymer with chloroacetic acid or its sodium, potassium or ammonium salt in an aqueous medium at a temperature of 5 to 90 ° C in a molar ratio of pyridine nitrogen in the copolymer and chloroacetic acid or said salts thereof : 0.5 to 1: 1.5. Severography, n. P., MOST Price 2,40 Kčs