KR100618647B1 - A purification method of bead-typed sulfonated poly (styrene-co-divinyl benzene) to get the low frangibility - Google Patents

Abstract

The present invention relates to a method for purifying a bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer having low breakability, and more particularly, to a bead-sulfonic acid-based poly (styrene-co) containing sulfuric acid as an impurity. In the method of eluting sulfuric acid from a divinylbenzene) copolymer, using a solvent having a swelling ratio with respect to the copolymer in a specific range, the solvent is selected using a solvent so that the swelling ratio is gradually increased. Purification method of the bead sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer which maintains the physical and chemical stability of the bead type copolymer and has a low cracking property and at the same time improves the removal rate of the sulfuric acid solution contained in the bead. It is about.

Sulfuric acid, swelling ratio, gradual, breakable, bead sulfonic acid poly (styrene-co-divinylbenzene) copolymer

Description

A purification method of bead-typed sulfonated poly (styrene-co-divinyl benzene) to get the low frangibility}

The present invention relates to a method for purifying a bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer having low breakability, and more particularly, to a bead-sulfonic acid-based poly (styrene-co) containing sulfuric acid as an impurity. In the method of eluting sulfuric acid from a divinylbenzene) copolymer, using a solvent having a swelling ratio with respect to the copolymer in a specific range, the solvent is selected using a solvent so that the swelling ratio is gradually increased. Purification method of the bead sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer which maintains the physical and chemical stability of the bead type copolymer and has a low cracking property and at the same time improves the removal rate of the sulfuric acid solution contained in the bead. It is about.

According to the results studied so far, in the preparation of ion-exchange resins and chelate resins having a sulfonated group as a functional group, sulfonating agents include 1) sulfurous acid (SO ₃ ) gas [US Patent Nos. 4,209,592, 5,280,082; Japanese Patent Application Laid-Open No. 03014803A2 (1991), Hei 8-299777 A2, Hei 9-0077824 A2, Hei 10-000346 A2], 2) Chlorosulfonic acid [US Pat. No. 4,671,903, Polym. Adv. Technol., 9, 107 (1998), Japanese Patent Laid-Open No. 62048737A2 (1962)], 3) fuming sulfuric acid [Zh. Prikl. Khim., 70 (12), 1970 (1974), Angew. Makromol. Chem., 263, 71 (1998), Japanese Patent Laid-Open No. 10101732A2 (1998)], 4) concentrated sulfuric acid [Makromol. Chem. Phys., 199 (11), 2527 (1998), PCT Int. Appl. International Patent Publication No. WO 99 / 28234A1 (1999), J. Chem. Educ., 66 (7), 613 (1989). These were copolymerized in spherical form (= bead) using styrene and divinylbenzene as a matrix, and the sulfonating agent was made to react with the phenyl ring of a styrene unit structure, and the ion exchange resin containing a sulfonic acid group was obtained.

In addition, related sulfonic acid-based ion exchange resins were introduced with mercapto groups [US Pat. Nos. 2,923,744, 4,387,251, 4,825,010, 4,859,803, 4,996,373, 5,212,206, 5,248,838, 5,939,494. Efforts have been made to increase the adsorption capacity of ion exchange resins.

The sulfonation method is introduced to increase the efficiency of sulfonation, and in purifying a resin prepared by performing sulfonation reaction using various sulfonating agents, a sulfuric acid component with a halogenated alkane solvent is usually more than the molar ratio of quantification. As such, the purification process is performed to elute the remaining unreacted sulfuric acid solution in the beads due to the excessive use. During the purification process, the sulfonated bead product may be filtered out of the solid solution as it is or beforehand to elute the unreacted sulfuric acid aqueous solution from the solid. At this time, as a solvent used for elution, methanol, ethanol, diethyl ether, distilled water, etc. are mainly used, but beads of resins formed by a large amount of mixed heat generated by mixing little or all at once with unreacted sulfuric acid solution are used. Cracking phenomenon occurs.

This means that when the elution solvent penetrates into the unreacted sulfuric acid solution together with the halogenated alkane solvent contained in the beads, the heat of mixing with sulfuric acid is greatly generated. It loses or destroys at the same time, and at the same time, it loses its merchandise and its functionality.

Therefore, in order to ensure that copolymers such as ion exchange resins and chelate resins having sulfonated groups as functional groups have a physically and chemically stable structure and excellent mechanical strength, unreacted sulfuric acid remaining in the beads after the sulfonation reaction is purified. The process should be such that the beads themselves are kept to a minimum of physicochemical effects and are kept in the form of beads that are wet to be applied to the site immediately.

Thus, the inventors of the present invention, when performing the purification process to remove the unreacted substance remaining in the resin as a functional sulfonated group as described above, the phenomenon of cracking the beads formed of the resin by reaction with a solvent for eluting the unreacted substance and The research efforts were made to solve the problem of deterioration. As a result, the sulfuric acid was eluted using a solvent having a swelling ratio of 1.0 to 1.5 with respect to the bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer containing sulfuric acid as an impurity, but the swelling ratio gradually increased. By eluting with a solvent, if possible, it was found that the beads could be purified without cracking, thereby completing the present invention.

Accordingly, the present invention physically and chemically stable by selecting and using a solvent that maintains the swelling ratio of the bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer in a specific range and gradually increasing it. It is an object of the present invention to provide a method for purifying a bead sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer in which the cracking phenomenon of beads is considerably reduced.

The present invention is a method of purifying sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer containing sulfuric acid as an impurity by eluting sulfuric acid,

Sulfuric acid-based poly (styrene-co-divinylbenzene) air which elutes and removes sulfuric acid using a solvent having a swelling ratio of the copolymer in the range of 1.0 to 1.5, but gradually increasing the swelling ratio of the copolymer. Its characteristics are in the purification method of coalescence.

Hereinafter, the present invention will be described in detail.

The present invention is based on a bead-type copolymer made of styrene, methyl methacrylate, divinylbenzene and the like as a basic skeleton, and the bead type obtained by performing sulfonation reaction of the copolymer prepared above in sulfuric acid and a halogenated alkane solvent. The present invention relates to a method for purifying sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer, which is not particularly easy to remove among the remaining compounds of unreacted sulfuric acid, water and halogenated alkanes in the beads during the sulfonation reaction. The present invention relates to a method for purifying a bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer by removing sulfuric acid by elution, wherein the swelling ratio for the copolymer is gradually increased within a specific range with a solvent used in the elution. The present invention relates to a method for efficiently removing remaining compounds without causing cracking of beads when properly selected and used for contact.

Conventionally, methanol, ethanol, isopropanol, diethyl ether and distilled water were mainly used as the elution solvent. However, when the alcohol-based solvents of methanol and ethanol are suddenly introduced at a time or the alcohol-based solvent is replaced with distilled water, these elutions are performed. The solvents were broken by the heat of miscification generated by mixing with the unreacted sulfuric acid remaining in the copolymer. In addition, although there is a difference according to the speed and the amount of the solvent injected during mixing, there is a problem in controlling the cracking phenomenon caused by this. In other words, the content of sulfuric acid solution which is used in excess to improve the sulfonic acid conversion rate and remains in the beads has a greater influence on the shape retention of the beads.

The present invention gradually increases the swelling ratio while using a solvent in which the swelling ratio of the copolymer is in the range of 1.0 to 1.5 as an elution solvent in order to minimize the physical and chemical effects of the compound remaining in the beads. While elution to minimize the physical and chemical effects of the purification process, while using distilled water as the final elution solvent to maintain the form of water-swelled bead substituted by distilled water for industrial applications It is characterized by the reduced. That is, the present invention is characterized not only by the selective use of an eluting solvent but also by a specific combination of solvents which gradually increases the swelling ratio for the beads.

The method for purifying the bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer according to the present invention will be described in more detail as follows.

First, the bead-type poly (styrene-co-divinylbenzene) copolymer resin is not particularly limited to a method generally used in the art, but in the present invention is prepared by radical suspension polymerization of styrene and divinylbenzene monomer as an example. . In this case, as the suspending agent, methyl cellulose, partially hydrolyzed polyvinyl alcohol, polyvinylpyrrolidone or a mixture thereof is used, and 0.01 to 4.0% by weight, preferably 0.1 to 2.0% by weight, based on the total amount of the monomers. Used as. The content of the suspending agent is a constant factor for determining the size of the bead-like copolymer when the stirring rate is constant and the weight ratio of water to the organic monomers below is determined. Such suspension polymerization is generally carried out in an aqueous dispersion, and the radical polymerization according to the present invention is carried out in an aqueous dispersion phase. At this time, water is used in the range of 0.5 to 15% by weight based on the total amount of monomers, and when the amount is less than 0.5% by weight, the viscosity becomes too large to obtain a uniform aqueous dispersion, whereas in the case of exceeding 15% by weight, the productivity This lowers and requires a large amount of water to heat up, resulting in high energy consumption, which is not good. In addition, a radical initiator is used as the radical suspension polymerization, and specifically, benzoyl peroxide, p, p'-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, di-t-butyl peroxide and potassium persulfate Or both a peroxide initiator, such as ammonium persulfate, and an azo radical initiator, such as bis azoisobutylonitrile, can be used.

Next, the poly (styrene-co-divinylbenzene) copolymer prepared by the radical suspension polymerization in the above is prepared using sulfonating agents such as SO ₃ gas, chlorosulfonic acid, pyrogenic sulfuric acid and concentrated sulfuric acid, which are generally used in the art. Perform the sulfonation reaction. In order to improve the efficiency of the sulfonation reaction, sulfuric acid is used in excess of quantitatively in a halogenated alkane solvent.

Since the reaction with the sulfone depends on the degree of crosslinking of the copolymer, it is preferable to use a conventional crosslinking agent used in the art. At this time, the crosslinking agent is used in 6 to 20 parts by weight based on 100 parts by weight of the copolymer, if less than 6 parts by weight of the swelling during the sulfonation reaction is too large to move the sulfonating agent to the inside of the beads is not easy sulfonation conversion rate is reduced In the case of more than 20 parts by weight, the swelling property for the halogenated alkanes is lowered and the sulfonation conversion rate is rather reduced.

Sulfuric acid is used to improve the sulfonation reaction rate, and in order to keep the content of the unreacted sulfuric acid aqueous solution in the beads as low as 1.1 to 3.2 parts by weight based on 100 parts by weight of the copolymer, the sulfonation conversion rate is less than 1.1 parts by weight. Relatively little, less heat of mixing with unreacted sulfuric acid solution such as methanol and ethanol, less bead cracking regardless of single use, mixed use or order of use. The presence of a large amount of unreacted sulfuric acid solution in the product beads causes bead cracking in all cases regardless of the choice of elution solvent or in any order.

In addition, conventional halogenated alkane solvents used in the art as swelling solvents for sulfonation reactions, specifically dichloromethane, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane and When 1,1,2-trichloroethane etc. are used, it is used in 1.5-5 weight part with respect to 100 weight part of said copolymers. If the amount is less than 1.5 parts by weight of the sulfonating agent solution is large viscosity of the sulfonation conversion rate is lowered, if it exceeds 5 parts by weight, the sulfonating agent is also present in the outside of the bead to also lower the sulfonation reaction rate.

In addition, since the unreacted sulfuric acid aqueous solution has a relatively high viscosity, an organic solvent such as acetic acid, methyl acetate, ethyl acetate, propyl acetate, acetic anhydride, and chloroacetic acid is additionally used to lower the viscosity when the sulfonation reaction is performed. 0.2-1.5 weight part is used with respect to 100 weight part of said copolymers. If the amount used is less than 0.2 parts by weight, the effect of lowering the viscosity is less, so that the sulfonation reaction rate is less improved. If the amount is more than 1.5 parts by weight, the sulfonation agent is diluted a lot, and thus the sulfonation reaction rate is slowed.

The sulfonation reaction is carried out within 6 to 20 hours to avoid the cracking and hydrolysis of the sulfonic acid group based on the bead, and when the reaction time is less than 6 hours, the aqueous sulfuric acid solution accumulates during the reaction, causing bead cracking. When the reaction time exceeds 20 hours, the hydrolysis of the sulfonic acid group occurs, but rather, the sulfonation conversion rate decreases and the unreacted sulfuric acid aqueous solution increases, thereby causing a lot of bead cracking.

In addition, the sulfonation reaction is carried out in the temperature range of 100 ~ 150 ℃ bar, if the reaction temperature is less than 100 ℃ low sulfonation conversion rate, if it exceeds 150 ℃ hydrolysis of the sulfonic acid group occurs rather than sulfonation The conversion rate is lowered and a lot of bead cracking occurs because sulfonation is overheated in a short time.

However, as described above, an aqueous sulfuric acid solution is contained in the bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer as a target component by using an excess sulfuric acid component, and eluting when performing a purification reaction to elute it. The bead state is broken by the heat of mixing with the solvent.

In the present invention, the solvent is eluted by using a solvent having a swelling ratio of 1.0 to 1.5 for the sulfonated poly (styrene-co-divinylbenzene) copolymer as the elution solvent, and eluting while gradually increasing the swelling ratio. The sulfuric acid contained as an impurity is purified.

In general, the sulfonated poly (styrene-co-divinylbenzene) copolymer is lipophilic before sulfonation, but the affinity for the solvent is changed to hydrophilic after the sulfonation reaction. That is, halogenated alkane solvents used as swelling solvents before the sulfonation reaction come out of the beads, and in the final product, a relatively large amount of unreacted sulfuric acid solution remains, and they do not elute in lipophilic solvents, but only in hydrophilic solvents. This can be

Such hydrophilic solvents include, for example, amides such as dimethylacetamide and dimethylformamide, esters of methyl acetate and ethyl acetate, ethers such as diethyl ether and petroleum ether, alcohols such as methanol and ethanol, and the like. Conventionally, this was used as an elution solvent in the purification process of the final product.

However, amides have high boiling point, making it difficult to separate and recover. When mixed with aqueous sulfuric acid solution, acid-base neutralization reaction heat is generated, and esters have low affinity for extraction due to poor compatibility with the product and complete miscibility with aqueous sulfuric acid solution. There is a problem of high boiling point, ethers have a problem of affinity with aqueous sulfuric acid solution, but low boiling point, a lot of scattering in the air, unsatisfactory extraction ability. On the other hand, the alcohol-based organic solvent is completely miscible with distilled water, and it is relatively easy to adopt and separate as a solvent extraction method in a sulfuric acid solution.

Therefore, although the swelling ratio with respect to a copolymer can use the elution solvent of 1.0-1.5 range, it is more preferable to use alcohol and distilled water with high affinity for sulfuric acid. The alcohol is preferably selected from one having 1 to 3 carbon atoms, which also considers affinity with sulfuric acid as described above. In this case, when the swelling ratio is less than 1.0, the elution effect of the unreacted sulfuric acid by the solvent is small, and when the swelling ratio is higher than 1.5, the bead cracking occurs easily due to the elution in the state where the bead strength is weakened due to the large swelling ratio by the elution solvent. do.

The solvent gradually raises the swelling ratio for the copolymer to replace all the eluting solvents finally used with distilled water, thereby substituting all the distilled water suitable for industrial application to obtain a water-swelled final product.

In more detail, as in Experiment 1, the swelling ratio of each solvent with respect to the copolymer contained in the sulfuric acid solution and the highly hydrophilic halogenated alkane organic solvent was measured. Distilled water shows the largest swelling ratio in the solvent. That is, an alcohol solvent is used as the initial solvent for elution, and the swelling ratio with respect to the copolymer is gradually increased. At the end of the elution, sulfuric acid is eluted by stepwise substitution through a solvent combination using distilled water. At this time, the elution of the alcohol solvent is preferably carried out at a pH of the product solution at least 1 condition, if the pH is lower than this, bead cracking due to excessive mixing heat with the elution solvent with the unreacted sulfuric acid remaining in the beads Will occur.

As described above, the impact of bead swelling is alleviated from sudden swelling and excessive mixing heat generated by distilled water, so that the final water-swelled product can be obtained without breaking the beads. The final products are preferably kept in a water swelled state. In the case of the distilled water, the unreacted sulfuric acid is completely removed by the selective use of a gradual solvent as in the present invention, dried, and then placed in distilled water again, and even if the swelling is temporarily increased, the bead itself may be destroyed. It is safe to maintain and high in industrial use.

One example of the eluting solvent combination used in the present invention may be methanol, methanol / ethanol mixture, ethanol, ethanol / distilled water mixture and distilled water and the like.

The elution solvent is used in a 1 to 6 volume ratio with respect to the copolymer. When the amount is less than 1 volume ratio, the elution effect is small, and when the amount exceeds 6 volume ratio, excessive mixing heat is generated temporarily. It is important. In addition, each eluting solvent is preferably eluted by stirring for 1 to 5 hours at room temperature in order to satisfy the mild dissolution conditions.

Such the present invention will be described in more detail based on the following examples, but is not limited to the present invention.

 Preparation Example: Preparation of Sulfonated Poly (styrene-co-divinylbenzene) Copolymer

An aqueous dispersion medium (α = 3.3) in which 0.1% hydroxyethyl cellulose (50 cps) was dissolved as a dispersion stabilizer was added to a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a condenser and stirred for 30 minutes. Thereafter, 27.920 g of styrene (St), 10.754 g of 57% divinylbenzene (DVB), 0.51 g of benzoyl peroxide, and 3.4 g of toluene were stirred for 30 minutes at room temperature, followed by stirring at 80 ° C. Suspension polymerization was carried out for 8 hours. The reaction was washed five times or more with distilled water and methanol each time to remove impurities, and vacuum dried at 60 ° C. for 48 hours to obtain 33.42 g of a spherical polymer (yield: 98.15%), which was 60/80 mesh. The sieve was filtered and used as a sample for the next reaction.

Experimental Example: Measurement of Swelling Ratio

The swelling ratio according to the type of elution solvent that can be used in the purification process of poly (styrene-co-divinylbenzene) was measured by the following method and is shown in Table 1 below.

In this case, 18% cross-linked poly (styrene-co-divinylbenzene) was used as a mixed solution in which the copolymer and sulfuric acid maintained a ratio of 1: 1.3, and 80% was sulfonated. It was used in 4 weight ratio with respect to the dry solid of coalescence.

How to measure the swelling ratio: Insert 0.1-0.5 g of sample resin using a 10 mL measuring cylinder, fill the cylinder flat on a rubber plate, and read the reading on the top of the surface. Thereafter, each of the eluted solvents was put far higher than the filled resin height, and then deposited at room temperature for 24 hours, and the scale value (cm) of the top of the swollen resin was read and calculated by the following equation.

[Equation]

Swelling ratio = [top height at swelling] (cm) / [top height at drying] (cm)

division Solvent Type Swelling ratio One Methanol 1.06 2 ethanol 1.37 3 Isopropanol 1.28 4 Diethyl ether 1.08 5 Methanol / ethanol (1: 1 weight ratio) mixed solution 1.20 6 Ethanol / distilled water (1: 1 weight ratio) mixed solution 1.40 7 Isopropanol / distilled water (1: 1 weight ratio) mixed solution 1.35 8 Diethyl ether / distilled water (1: 1 weight ratio) mixed solution 1.25 9 Methyl acetate 1.23 10 Ethyl acetate 1.32 11 Distilled water 1.44

Example 1: Purification of Sulfonated Poly (styrene-co-divinylbenzene) Copolymers

To 25 g of the copolymer resin obtained in the preparation example, 135 mL of 1,2-dichloroethane was poured and swelled in advance for about 1 hour. Then, 32.5 g of concentrated sulfuric acid was added thereto, followed by sulfonation at 130 ° C. for 10 hours. An unreacted sulfuric acid solution containing the final product, a mixed solution containing 1,2-dichloroethane and the like were obtained, and the following purification process was performed. At this time, the mixed solution was poly (styrene-co-divinylbenzene) having 18% crosslinking degree, and the copolymer and sulfuric acid maintained a ratio of 1: 1.3, and 80% was sulfonated.

While stirring the mixed solution, 100 mL of methanol was slowly added thereto over 30 minutes, and then 100 mL of methanol / ethanol (1: 1 weight ratio) was slowly added thereto over 30 minutes, followed by stirring for 1 hour. Was separated. 100 mL of methanol / ethanol (1: 1 weight ratio) was slowly added to the separated solid over 30 minutes, followed by slow addition of 100 mL of ethanol / distilled water (1: 1 weight ratio), followed by 1 hour. By stirring, the solids were separated. 100 mL of ethanol / distilled water (1: 1 weight ratio) was slowly added to the separated solid over 30 minutes, and then 100 mL of distilled water was added slowly to the solid, followed by stirring for 1 hour. Came out. 100 mL of distilled water was slowly added to the separated solid over 30 minutes, stirred for 1 hour, and then separated into a water-swelled sulfonated poly (styrene-co-divinylbenzene) copolymer without separation in principle ( Dried weight: 40.72 g).

Examples 2-18: Purification of Sulfonated Poly (styrene-co-divinylbenzene) Copolymers

The same procedure as in Example 1, but as shown in the following Table 2 sulfonated poly (styrene-co-divinylbenzene) water-swelled by performing a purification reaction using a swelling ratio from the low swelling ratio to the elution solvent gradually A copolymer was obtained.

The breaking rate of the sulfonated poly (styrene-co-divinylbenzene) copolymer obtained above was measured and shown in Table 2 below.

Comparative example  1 to 9: Sulfonation Poly (Styrene-co- Divinylbenzene Purification of Copolymer

Performed in the same manner as in Example 1 using the copolymer resin obtained in the above Preparation Example, but as shown in Table 3 below from the low swelling ratio to gradually use the elution solvent as a dissolution solvent sulfonated poly ( Styrene-co-divinylbenzene) copolymer.

The breaking rate of the sulfonated poly (styrene-co-divinylbenzene) copolymer obtained above was measured and shown in Table 3 below.

As shown in Table 2 and Table 3, the purification reaction was performed while changing the elution solvent while gradually increasing the swelling ratio of methanol, methanol / ethanol mixed solution, ethanol, ethanol / distilled water mixed solution and distilled water; 18 shows that the phenomenon of cracking was significantly reduced compared to Comparative Examples 1 to 9 using methanol, ethanol, and distilled water, which had a sharply increased swelling ratio.

In addition, it was confirmed that the cracking rate was further lowered in Examples 16 to 18 in which the swelling ratio was changed more finely by varying the ratio of the methanol / ethanol mixed solution and the ethanol / distilled water mixed solution.

In Comparative Examples 1 to 9, the higher the elution rate in the order of methanol, ethanol and distilled water, the larger the degree of cracking was observed. In methanol, when swelling is low, it can bring about a small amount of cracking. However, beads collected with little cracking are also mixed with distilled water having high swellability. In addition, it was shown that a longer stirring time during the elution process can lead to less cracking in common.

On the other hand, when each of the eluting solvents alone, the increase in the swelling ratio and the degree of breaking represented by the dried final product was found to be proportional, and the alcohol-based eluting solvent was less broken than distilled water. Therefore, most of the aqueous sulfuric acid solution was extracted and removed by alcoholic elution solvent and replaced with distilled water.

In addition, the lower the concentration of the unreacted sulfuric acid solution contained in the copolymer during refining, the better. However, when the sulfonation reaction rate itself decreases and is excessive, the amount of elution solvent and the elution time are long or long, and the degree of breakage due to excessive mixing heat is high. As it grows larger, it is important to keep it appropriate.

As described above, the present invention, after performing the sulfonation reaction to the poly (styrene-co-divinylbenzene) copolymer resin, the unreacted sulfuric acid aqueous solution which is the remaining compound contained in the product obtained in a specific swelling ratio The alcohol-based organic solvent having distilled water and distilled water are all used sequentially, and the breakage rate of the beads is significantly lower than that of the conventional purification process.

Claims (6)

In the method for purifying sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer containing sulfuric acid as an impurity, Sulfuric acid-based poly (styrene-co-di) characterized in that the sulfuric acid is eluted and removed using a solvent having a swelling ratio of the copolymer in the range of 1.0 to 1.5, while gradually increasing the swelling ratio of the copolymer. Vinylbenzene) copolymer purification method. The method of claim 1, wherein the solvent is selected from C ₁ to C ₃ alcohols and distilled water. The bead-type sulfonic acid-based poly (styrene-co-divinylbenzene) copolymer according to claim 1 or 2, wherein alcohol is used as the initial elution solvent and distilled water is used as the final elution terminal. Purification method. [4] The bead sulfonic acid poly (styrene-co-divinylbenzene) according to claim 3, wherein the elution using the initial alcohol solvent is performed until the pH of the sulfonated copolymer mixed solution becomes at least 1. ) Purification method of the copolymer. The bead sulfonic acid poly (styrene-co) according to claim 1, wherein the elution is performed while gradually increasing the swelling ratio in the order of methanol, a mixture of methanol / ethanol, ethanol, ethanol / distilled water mixture, and distilled water. -Divinylbenzene) copolymer purification method. The method of claim 1, wherein the elution is carried out using 1 to 6 parts by volume of solvent based on the copolymer, and the method of purifying the bead sulfonic acid poly (styrene-co-divinylbenzene) copolymer.