JPS591725B2 - Method for manufacturing cation exchange resin - Google Patents

Description

[Detailed description of the invention] The present invention relates to a novel method for producing cation exchange resins.

Specifically, among (i) styrene sulfonic acids, (ii) polyvinyl monomers having two or more vinyl groups, (111) monovinyl monomers having one vinyl group, the above (1)
) and (11) or a monomer mixture selected from the combinations of (1), (11) and (110) is copolymerized in an acetic acid solvent in the presence of a radical polymerization initiator. Conventionally, cation exchange resins are produced by adding a polyvinyl monomer such as divinylbenzene as a crosslinking agent to a monovinyl monomer capable of introducing a functional group, such as styrene, in the presence of a radical polymerization initiator. A method in which a crosslinked copolymer into which an exchange standard can be introduced is first produced by a suspension polymerization method, and then sulfonated using a sulfonating reagent such as sulfuric acid to introduce a cation exchange group into the crosslinked copolymer. is common.

In addition, as a special method, a monovinyl monomer having a cation exchange group such as styrene sulfonic acid and a crosslinking agent such as divinylbenzene are combined in the presence of a radical polymerization initiator such as dimethylformamide (hereinafter referred to as DM).
A method of copolymerization in a special solvent such as F) or dimethyl sulfoxide (hereinafter abbreviated as DMSO) is known. However, these methods of producing cation exchange resins have various drawbacks as described below.

First, in the former case, for example, when the purpose is to produce a cation exchange resin with a small particle size, the fine particulate cation exchange resin after sulfonation will clog the filter, making it difficult to separate it from the sulfonation reagent. There are disadvantages such as coloring of the cation exchange resin obtained by the oxidation effect of the sulfonating reagent and contamination of the dispersant used during suspension polymerization into the resin.
In the latter case, when DMF is used as a solvent, the cation exchange resin is obtained as a viscous slurry;
When this is used, an agar-like cation exchange resin that is significantly swollen due to the solvent is obtained. Therefore, it is difficult to separate and purify the cation exchange resin produced from these solvents, and it is necessary to wash the cation exchange resin repeatedly with water or methanol to completely remove the solvent. Resins are amorphous lumps and have many drawbacks, such as the need for further crushing and sieving before use. 05 The present inventors have been diligently researching the production of cation exchange resins in order to compensate for the various deficiencies of the above-mentioned cation exchange resins.

As a result, when styrene sulfonic acids and a polyvinyl monomer having two or more vinyl groups, such as divinylbenzene, are copolymerized in an acetic acid solvent, a finely divided cation exchange resin can be obtained, and the above-mentioned conventional defects can be completely compensated for. They discovered that this can be done and completed the present invention. That is, the present invention provides (1) and (1) or (1) among (1) styrene sulfonic acids, (4) polyvinyl monomers having two or more vinyl groups, (11!) monovinyl monomers having one vinyl group, This is a method for producing a cation exchange resin in which a monomer mixture selected from the combinations (4) and (111) is copolymerized in an acetic acid solvent in the presence of a radical polymerization initiator.

Styrene sulfonic acids, polyvinyl monomers, and monovinyl monomers are all known as raw materials for ion exchange resins.

In the present invention, these known materials can be used without particular limitation. Typical examples of those generally suitably used are as follows. That is, as the styrene sulfonic acids, styrene sulfonic acid, salts of styrene sulfonic acid, particularly alkali metal salts represented by sodium and potassium, and ammonium salts are preferably used. Polyvinyl monomers having two or more vinyl groups are generally used as crosslinking agents such as m-, p-, 0-divinylbenzene, divinylsulfone, butadiene, chlorobrene, isoprene, trivinylbenzenes, divinylnaphthalene, and trivinylnaphthalene. Known materials are preferably used.
Furthermore, monovinyl monomers having one vinyl group generally include styrene, ethylvinylbenzene, chloromethylstyrene, acrylonitrile, vinyl chloride,
Monomers such as acrylic acid and maleic acid are preferably used. The combination of monomer mixtures in the present invention may be either a two-component monomer mixture of styrene sulfonic acids and a polyvinyl monomer, or a three-component monomer mixture in which a monovinyl monomer is further added to these monomer mixtures.

These combinations vary depending on the properties required of the resulting cation exchange resin and cannot be limited unconditionally. As a general trend, when the above-mentioned two-component monomer mixture is used, the ion exchange capacity can be increased, and when the above-mentioned ternary monomer mixture is used, the function of the resulting cation exchange resin can be changed. For example, when chloromethylstyrene is used as the third component, it can be further quaternized with trimethylamine to produce an amphoteric ion exchange resin. The composition ratio of the monomer mixture varies depending on the properties of the cation exchange resin required, such as strength, degree of crosslinking, amount of ion exchange groups, etc., and cannot be absolutely limited, but in general, polyvinyl monomers are used for styrene sulfonic acids. 10
A range of 300% by weight is preferably used. Further, in the case of a three-component monomer mixture using a monovinyl monomer, a suitable range is 10 to 300% by weight based on the styrene sulfonic acid. Further, generally, the ion exchange capacity of the cation exchange resin obtained by the present invention almost coincides with the value calculated from the raw material monomer composition ratio.

Furthermore, if the amount of polyvinyl monomer used becomes extremely small, for example, 10 (weight (f
/)) If the amount is less, the yield of the cation exchange resin obtained tends to decrease, so it is generally preferable to use 10 (weight (f)) or more based on the styrene sulfonic acids. The polyvinyl monomer may be determined with emphasis on controlling the degree of crosslinking of the cation exchange resin obtained and controlling the yield. Furthermore, the amount of monovinyl monomer added is preferably determined in consideration of controlling the ion exchange capacity of the generally obtained cation exchange resin. The most important feature of the present invention is that the monomer mixture is copolymerized in an acetic acid solvent.

When formic acid, propionic acid, butyric acid, etc. are used instead of the acetic acid solvent, it is almost impossible to obtain a crosslinked copolymer that can be used as a cation exchange resin. Therefore, it is extremely important for the present invention to use acetic acid as a solvent. The concentration of the monomer mixture in the acetic acid solvent is not particularly limited and may be appropriately determined in advance as necessary, but in general, increasing the monomer concentration will increase the yield of the cation exchange resin relative to the monomers charged. The rate tends to be high. The copolymerization conditions for the monomer mixture vary depending on the type of radical polymerization initiator, the type and composition ratio of the monomer mixture, etc., which will be described later, and cannot be unconditionally limited. The time scale is most preferably employed. The copolymerization of the monomer mixture in the present invention may be carried out in the presence of a known radical polymerization initiator.

Typical radical polymerization initiators include benzoyl peroxide, acetyl peroxide, di-T peroxide, etc.
Peroxides such as ert-butyl, cumene hydroperoxide, azo compounds such as p-prombenzenediazonium hydroxide, triphenylmethylazobenzene, αα7-azobisisobutyronitrile, N-nitrosoacylanilide, tetraphenylsuccinimide, etc. Nonitrile and the like are preferred. The amount of these radical polymerization initiators to be added may be determined as appropriate, but in general, the amount of the radical polymerization initiator added is 0 to the monomer mixture.
．． 1% by weight is sufficient. Further, the polymerization temperature may be appropriately selected and determined depending on the decomposition temperature of the radical polymerization initiator used. The cation exchange resin obtained in the present invention generally has 10 to 100 aggregates of spherical primary particles of 1 to 10 μm.
Obtained as μ granules.

Therefore, separation from the acetic acid solvent or washing of the separated cation exchange resin with water, methanol, etc. is extremely easy. Further, the cation exchange resin of the present invention does not aggregate into lumps even after drying and is very easy to handle.
Furthermore, the cation exchange resin obtained in the present invention is white and does not contain any colored components, and also has no components extracted into organic solvents. Therefore, the cation exchange resin of the present invention can be suitably used in fields where it could not be used conventionally due to colored components or components extracted into organic solvents, such as separation and analysis fields. EXAMPLES In order to more specifically illustrate the present invention, Examples will be given below, but the present invention is not limited to these Examples. Example 1 A glass reactor with a capacity of 300r7Le equipped with a reflux device and a stirrer was sufficiently purged with nitrogen, and purified acetic acid 100
rrLe was injected, and commercially available potassium styrene sulfonate (purity of 90% or more) 7.0t and divinylbenzene with a purity of 50wt% (ethylvinylbenzene was an impurity of 45%) were added.
Contains ~50wt.

) was added thereto and thoroughly stirred at room temperature. After completely dissolving and mixing, benzoyl peroxide was added as a radical polymerization initiator (1 Wt0t) to all monomers, and as a result of reacting at a polymerization temperature of 80° C. for 18 hours, a white resin was produced. Filter this resin with a glass filter,
After thorough washing with methanol and water, the potassium sulfonate form of this resin was converted into a hydrogen ion form with a 1N aqueous solution of monohydrochloric acid, followed by thorough washing with water and vacuum drying. When the weight of the resin thus obtained was measured, it was found to be 13.0V. When this resin was observed with a scanning electron microscope, it was found that
The aggregate diameter of primary particles of approximately 5-6 μm in diameter is approximately 1
It was found that it was in the form of granules consisting of 0 to 100μ. When the hydrogen ion type ion exchange resin was weighed at 1.0 V and immersed in a 1M sodium monochloride aqueous solution, it suddenly became acidic. The ion exchange capacity was measured by neutralization titration of this aqueous solution with a 0.1N aqueous sodium monohydroxide solution using methyl orange as an indicator, and found to be 1.70 meq.
/DryltH+ type. From this result, it was confirmed that it was a cation exchange resin. The above ion exchange resin was dissolved in an aqueous solution, a water-methanol mixed solution (methanol 1001
)) Add 100 d of each of the three types of water-tetrahydrofuran mixed solution (tetrahydrofuran 10(f)) to 100 d of each solution and leave it for about 1 month while stirring, and examine the absorption in the ultraviolet absorption spectrum of each solution. Similar to the previous solution, no new absorption spectra were observed.

For comparison, a commercially available strongly acidic cation exchange resin such as Amberlite IR-120B (trade name) was ground in a ball mill, thoroughly washed with water, and the ultraviolet absorption spectra were observed in the same three solutions as described above. As a result, 200 mμ, 25
Ultraviolet absorption spectra near 0 mμ and 310 mμ were observed. Example 2 Copolymerization was carried out in the same manner as in Example 1 except that the raw material monomers and radical polymerization initiator shown in Table 1 were used.

The results were as shown in Table 1. However, the polymerization time for Boiled 1 to 4 was 18 hours, and the polymerization time for Black 5 to 9 was 6 hours. Example 3 Using the reactor used in Example 1, 100ml of acetic acid was purified after being sufficiently purged with nitrogen! Inject commercially available potassium styrene sulfonate (90% purity or higher) 7.0y1 divinylbenzene with a purity of 50wt% to 10.0? and 10.0 y of chloromethylstyrene (purity 90% or more) were added thereto and thoroughly stirred at room temperature.

Claims (1)

[Claims] 1 (i) styrene sulfonic acids (ii) polyvinyl monomers having two or more vinyl groups (
iii) Among monovinyl monomers having one vinyl group, (i) and (ii) or (i), (ii) and (ii)
A method for producing a cation exchange resin, comprising copolymerizing a monomer mixture selected from the combination i) in an acetic acid solvent in the presence of a radical polymerization initiator.