CS196077B1 - Process for preparing hydrophylic macroporous ionexes - Google Patents

Description

The present invention relates to a process for the preparation of hydrophilic polymer gels which contain both cationic and anionic functional groups in their structure.

Ion exchange hydrophilic polymeric gels with adjustable porosity, prepared according to U.S. Pat. AO Nos. 171 962, 171 963 and 137 563, contain either anionic (cation exchanger) or cationic (anion exchanger) functional groups in their structure. It has been shown that these materials outperform the current commonly used cation exchangers and anion exchangers with cellulose or polydextran matrix in the sorption and chromatography of various biopolymers by their physical and chemical properties.

In addition to conventional cation exchangers and anion exchangers, however, synthetic organic polystyrene divinylbenzene ion exchangers have been previously prepared which contain both basic and acidic functional groups in their structure. An acid component (e.g. acrylic acid) has been sorbed onto the anion exchange polystyrene by anion exchange, which after penetration into the anion exchanger beads was then polymerized into its network, mostly by wedging its macromolecular chain. Similarly, it is possible to bind the basic components to a cation exchanger. These processes have produced commercial amphoteric ion exchangers, such as the Retardion type, which have been used primarily in a process called ion retardation. This separation process is applied both on a laboratory and production scale.

The recent development of biopolymers chromatography shows the great importance of amphoteric ion exchangers when their functional groups are bonded to a matrix allowing the penetration of macromolecules such as polydextran [/ J, Porath, L. Fryklund: Nature 226 (1970)]

169; J. Porath, N. Fornstedt, J. Chromarogr. Given the advantageous chemical and mechanical properties of the hydrophilic hydroxyacrylate and hydroxymethacrylate gels prepared according to U.S. Pat. U.S. Patent No. 148,828 and Author No. 150,819, which in many respects surpass derivatives of the polysaccharide, this synthetic polymer gel is a very suitable carrier for arafoteric or dipolar ionogenic groups.

SUMMARY OF THE INVENTION The present invention relates to a process for the preparation of hydrophilic macroporous ion exchangers of amphoteric character, particularly for the isolation and separation of biological materials, comprising: a macroporous hydrophilic cation exchanger consisting of a phosphorylated copolymer of 2-hydroxyalkylmethacrylate or C 2 -C 3 -acrylate and ethylene glycol or -acrylate, neutralized with basic reacting monomers from the group consisting of vinylpyridine, aminoalkyl methacrylates and aminoalkylacrylates containing from 1 to 3 carbon atoms in alkyl, and then reactive double bonds of the neutralization product are copolymerized radically with double bonds in the side chains of the original cation exchange resin.

The copolymerization can advantageously be carried out by first preparing a macroporous cation exchange suspension copolymer. of the crosslinker so that, after polymerization, the polymer contains some unreacted acrylic or raethacryolyl double bonds. If a monomer selected from vinylpyridines, arainoalkyl acrylates, aminoalkylraethacrylates, aminoalkylacrylamides or aminoalkylmethacrylamides or their quaternary ammonium compounds is now added to such a cation exchange resin, the remaining double bonds of the base cation exchange resin can only be copolymerized with the double bonds of the new cationic base monomer. . This creates a graft copolymer with amphoteric properties,

For the preparation of the macroporous hydrophilic cation exchanger, acrylic or methacrylic-type crosslinking monomers selected from the group of diacrylates and diraethacrylates such as dialkyl acrylates, dialkyl methacrylates, oligoglycol and polyglycol diacrylates, oligoglycol and polyglycol methacrylamides, bis-methacrylamides, bis-methacrylamides, bis-methacrylamides; The crosslinkers may also contain a plurality of acryloyl or methacryloyl copolymerizable groups. The free-radical copolymerization is carried out in the presence of inert organic solvents selected from the group of organic acids, alcohols, amines or nitriles in the aqueous dispersed phase.

In the synthesis of an amphoteric ion exchanger, the requirement that the oppositely charged groups are not only in stoichiometric equivalence, but that they are sterically positioned so as to allow their independent swirling in solution and position within the space defined by their arm lengths, is often important. It is desirable for them to meet at one point and form an ionic bond.

Amphoteric ion exchange hydrophilic gels are of great importance for the development of fine fractionation methods. They are separated by mixtures of proteins and nucleic acids already in linear chromatography, without the possibility of using elution gradients. The achieved results exceed the separation on amphoteric ion exchangers by the separation achieved on the usual monofunctional ion exchange derivatives. £ j. Porath: Chromatographic Methods in Fractionation of Enzymes / in Biotechnology and Bioengineering Symp. No. 3, 145-166, 1972. The Sephadex or Sepharose polydextran derivatives (protected word marks) hitherto used for this purpose have substantially less chemical and mechanical stability than hydrophilic derivatives of hydroxyacrylate and hydroxymethacrylate gels.

In addition, the new ion exchangers prepared according to the present invention swell very little, at higher flow rates, the columns filled with these materials do not clog. The gels are resistant to microbial infection and can be sterilized by boiling if necessary.

The following examples illustrate the preparation of the amphoteric ion exchangers of the present invention without, however, limiting the scope thereof. For example, the monomers listed above may be supplemented with other known cationic and anionic monomers such as salts of ethylene sulfonic acid, styrene sulfonic acid, quaternized aminoalkylstyrenes and the like.

Example 1

A copolymer of 2-hydroxyethyl methacrylate and ethylenedimethacrylate with a molecular weight cutoff of 300,000 (5 g) was swelled in ethyl acetate (100 ml), then the mixture was cooled to -20 ° C, in a three necked flask equipped with stirrer, thermometer, dropper with external cooling. a reaction was performed at -20 ° C. To the cooled gel suspension, 20 ml of solution (3 ml POCl 3 * 17 ml dry ethyl acetate) was added dropwise over 30 minutes with stirring and cooling. The solution was further stirred at this temperature for 10 minutes. The gel was then filtered, washed with ethyl acetate, acetone, methanol, water, methanol and dried from ether. 2 g of phosphorylated product with a capacity of about 2.5 meq / g was converted to pH form by washing with 20% HCl. The excess acid was washed with water. The gel was poured over with 4-vinylpyridine, the excess monomer was aspirated and washed with 2: 1 methanol-water. The gel was mixed with a minimum volume of acetone-water solution of 15: 1 with 10 wt. % azobisisobutyronitrile. The gel container was frozen, evacuated and purged with nitrogen. This procedure was repeated 3 more times, then the vial was sealed and placed in a 70 ° C thermostat. The gel was heated for 10 hours. Then the vessel was opened, the gel washed with methanol, 10: 1 acetone-water, acetone, ether. The gel was air dried, vacuum dried and the nitrogen content determined by elemental analysis and according to Kjehldal (1.75% N).

Example 2

The modification was carried out as in Example 1 except that N, N-diethylaminomethacrylate was used instead of 4-vinylpyridine. The Kjehldal nitrogen content was 1.1%.

Claims (1)

A process for the preparation of hydrophilic macroporous ion exchangers of amphoteric character, intended especially for the isolation and separation of biological materials, characterized in that the macroporous hydrophilic cation exchanger consisting of a phosphorylated copolymer of 2-hydroxyalkyl methacrylate or C2 -C3 -acrylate and ethylene glycol dimethacrylate reacting monomers from the group consisting of vinylpyridine, aminoalkyl methacrylates and aminoalkylacrylates containing from 1 to 3 carbon atoms in the alkyl, and then reactive double bonds of the neutralization product are radically copolymerized with double bonds in the side chains of the original cation exchange resin.