CS264761B1 - A method for purifying porous polymers - Google Patents

Abstract

A method for cleaning porous organic polymers from pore-forming inert solvents of the type of aliphatic or cycloaliphatic alcohols, by solubilizing them in an aqueous solution, by treating them with a surfactant of the type of alkylbenzenesulfonate salt and a water-miscible alcohol and/or ketone, by separating the aqueous solution from the polymer and washing out its polymerization residues with water.

Description

The invention relates to the purification of porous polymer particles from excipients used to form and regulate their porous structure.

Porous polymers prepared by block or suspension polymerization find use as adsorbents, carriers or matrices for modification by polymer-analogous reactions in various chromatography techniques as well as industrial adsorbents. They are, for example, glycol methacrylate or glycidyl methacrylate polymers whose porous structure is formed and controlled by the addition of inert solvents. These solvents are added to the monomer mixture and the polymerization is conducted in their presence. In preparing these porous polymers, mostly aliphatic or cycloaliphatic alcohols having a carbon number of 4 to 20, individually or in admixture with each other, are used as inert solvents.

Since, when porous polymers are used, even small residues of inert solvents interfere with the elution step, contaminate the eluate and modify the surface sorption properties of the porous polymers, they must be removed from the polymer by thorough washing with polar organic solvents. Due to the gel nature of the polymers and their swellability in water and polar organic solvents, the diffusion of substances from the interior of their particles is slow, their purification is lengthy and is associated with a considerable consumption of organic solvents.

To eliminate this drawback, a process for the purification of porous polymers containing, based on the purified polymer, 45 to 240% co-inert inert solvents is characterized, characterized in that after completion of the polymerization, co-inert solvents of aliphatic or cycloaliphatic alcohols having 4 to 20 carbon atoms are solubilize in the presence of water by mixing with a surfactant of the formula

(C _n H ₂ n * l)

an alcohol having a carbon number of 1 to 3 and / or ketones having a carbon number of 3 or 4, whereupon their aqueous solution is separated from the polymer and its residues are washed out of the polymer with water.

The ratio of water to purified polymer is 0.3 to 20, the ratio of surfactant to purified polymer is 0.15 to 3.5, and the ratio of alcohol and / or ketone to purified polymer is 0.15 to 5. All% and ratios are by weight .

The advantage of using two kinds of solubilizing agents, an anionic agent and a water-soluble organic solvent, is generally less reagents, and that the aqueous solution of solubilized inert solvents is dilutable in all ratios with water without separating the organic phase. Without the use of a polar organic solvent, it is also possible to dissolve the inert solvents in the aqueous polymerization mixture, but several times more surfactant and the resulting aqueous solution cannot be diluted with water because they dilute with dilute organic phase that adheres to the polymer particles.

The advantage of this method of purifying porous polymers is the saving of organic solvents which would have to be used to wash out inert water-immiscible organic solvents.

In the practice of this method of purifying porous polymers, the polymerization mixture should be mixed with the solubilizing agents for a sufficient period of time. Solubilization in the emulsion occurs immediately, but for porous polymers, some time is necessary to establish a concentration equilibrium between the polymer and the solution. The penetration of solubilizing agents into the polymer and the dissipation of solubilized inert solvents into the aqueous solution are limited by the rate of diffusion and this is dependent on the porous structure and degree of crosslinking of the polymer. The solubilizing agents may be added individually to the polymerization mixture, but preferably in admixture with each other. Excipients such as polyvinylpyrrolidone or polyvinyl alcohol used as stabilizers in suspension polymerization do not interfere with the polymer cleaning process. Waste aqueous solutions of inert solvents, solubilizers or other auxiliaries may be disposed of by incineration or separation of the organic phase by acidification. In an acidic environment, the surfactant loses its solubilizing effect.

Examples 1 to 5 illustrate a process for purifying a polymer of the invention. Examples 6 and 7 show a higher effect of the surfactant / organic solvent mixture than the components used alone. Example 8 illustrates high consumption of organic solvents, increased labor and time consuming current slurry polymer purification process

The residual organic content of the purified polymer was controlled by extracting a 5 gram polymer dose of acetone in a Soxhlet extractor for 1 hour, evaporating the acetone at 105 ° C, weighing the weight of the evaporator and expressing it as a percentage of the polymer weight. In some cases the extraction was carried out on an enlarged scale and the chemical composition of the residue was determined by gas chromatography. In addition, the volatiles were removed from the evaporator in a vacuum evaporator at 120 ° C and 100 Pa and the non-volatile residue was examined by nuclear magnetic resonance. These measurements showed that the nonvolatile fraction of the evaporator is relatively stable in amount, about 0.3% and consists of polymeric acrylates. The volatile portion of the residue is variable above depending on the polymer purification process and is formed by aliphatic and cycloaliphatic alcohols with traces of oligomeric acrylates. All% are by weight.

He did

The polymerization mixture consisting of 4.2 kg of spherical porous particles of hydroxyethyl methacrylate copolymer with ethylenedimethacrylate, inert solvents 5.6 kg of cyclohexanol and 0.51 kg of dodecanol, 0.31 kg of polyvinylpyrrolidone and 31 kg of water was stirred at room temperature for 5 hours. 5.5 kg monoethanolamine dodeoylbenzenesulfonate and 4.2 kg acetone. The solubilizing agent transferred the inert solvents of the polymer into an aqueous solution which was separated from the polymer by decantation. Residues of this aqueous solution were washed out of the polymer with water. The acetone extract residue of the purified polymer was 0.60%.

Example 2

The polymerization mixture containing 4.2 kg of porous hydroxyethyl methacrylate / ethylene dimethacrylate copolymer particles, inert solvents of 3.4 kg of cyclohexanol and 2.3 kg of dodecanol, and 1.57 kg of polyvinyl alcohol and 31 kg of water was stirred for 6 hours at room temperature with 6 kg. mixtures of alkylbenzene sulfonates having an alkyl length of 9 to 14 carbon atoms and 9.5 kg of isopropanol. The aqueous solution with solubilized inert solvents was separated from the polymer by decantation and washed with water on a filter pad. The purified polymer had an acetone extract residue weight of 0.75%.

Example 3

The polymerization mixture consisting of 4.2 kg porous particles of hydroxyethyl methacrylate copolymer with ethylene dimethacrylate, an inert solvent of 5.6 kg of cyclohexanol, 0.62 kg of polyvinylpyrrolidone and 31 kg of water was stirred at room temperature for 2 hours with 3.1 kg of sodium dodecylbenzenesulfonate and potassium. 5.95 kg of methanol. The aqueous solution was separated from the polymer by centrifugation and its residues were washed out of the polymer by repeated decantation with water. The purified polymer was found to have an acetone extract residue weight of 0.85%.

He attaches

Block polymerization polymer containing 4 kg of hydroxyethyl methacrylate-ethylene dimethacrylate copolymer, 5.5 kg of isoamyl alcohol and 0.5 kg of octadecyl alcohol was crushed and stirred at room temperature for 10 hours in a solution of 3 kg of diethylamine dodeoylbenzenesulfonate, 3 kg of dodeoylbenzenesulfonethane, and 30 kg of water. The solution was decanted and the copolymer was purified by washing with water by double sedimentation and decanting and washing with water on a filter pad. The acetone extract residue of this polymer reached 1.10 4.

Example 5

The polymerization mixture was purified as described in Example 1, which, unlike Example 1, contained a porous spherical copolymer of glycidyl methacrylate with ethylenedimethacrylate and an equimolar mixture of triethanolamine-dodeoylbenzenesulfonate-dodeoylbenzenesulfonate and dodeoylbenzenesulfonate-triethanolamine dodeoylbenzenesulfonate was used in the purification process. The acetone extract residue was 0.65%.

Example 6 of the polymer purification of Example 1 was repeated except that acetone was not used and the monoethanolamine dodeoylbenzenesulfonate content was increased from 5.5 kg to 10 kg. The weight of the acetone extract residue was 8.80%.

Example 7

Purification of the polymer of Example 1 was accomplished by omitting monoethanolamine dodecylbenzenesulfonate and increasing the amount of acetone from 4.2 kg to 10 kg. The polymer thus purified had an acetone extract residue weight of 14.10 4.

Example

The slurry polymerization mixture, consisting of 4.2 kg of spherical porous hydroxyethyl methacrylate copolymer with ethylenedimethacrylate, inert solvents 5.6 kg of cyclohexanol and 0.51 kg of dodecanol, 0.31 kg of polyvinylpyrrolidone and 31 kg of water, was purified from the excipients by hot dilution. 60 kg water, six hours of sedimentation of the purified polymer and decantation of the supernatant. Stirring operations with 50 liter portions of hot water, polymer sedimentation and decantation of the supernatant were repeated three more times. After the fourth decantation, the polymer sediment was stirred in 50 liters of ethanol, allowed to settle and the supernatant was withdrawn by decantation. Thereafter, the purified polymer was washed in a filter bottom column at a slow flow rate of 50 liters of acetone and further washed with water until the acetone was removed. In the copolymer thus purified, the acetone extract residue was 0.80.

Claims (2)

SUBJECT OF THE INVENTION A process for the purification of porous polymers containing, based on the purified polymer, 45 to 240% by weight of inert co-solvents, characterized in that after completion of the polymerization, co-inert solvents of the aliphatic or cycloaliphatic alcohol type having a carbon number of 4 to 20 are solubilized in the presence of water by stirring with a surfactant of the formula | ^c n ^H n + 1) where n is 8 to 15 and M is Na, K, NH ₄ , H ₃ NC ₃ H ₆ OH, H ₃ N (C ₃ H ₅ OH) ₂ , or HN (C ₂ H ₅ OH) ₃ and 3 and / or a ketone having a carbon number of 3 or 4, whereupon their aqueous solution is separated from the polymer and its residues are washed out of the polymer with water. 2. A method according to claim 1, wherein the weight ratio of water to purified polymer is from 0.3 to 0.20, the weight ratio of surfactant to purified polymer is from 0.15 to 3.5, and the weight ratio of alcohol; and / or the ketone to the purified polymer is 0.15 to 5.