JPH0465843B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a gel type sulfonic acid type highly productive cation exchange resin having a large specific gravity. More specifically, in the method of synthesizing a cation exchange resin with a large specific gravity by sulfonating a brominated styrene-divinylbenzene crosslinked copolymer, a cation exchange resin with no cracks and an excellent appearance is used. The present invention relates to a method for obtaining a resin. Conventionally, cation exchange resins, especially styrene-
Due to its excellent chemical and physical stability, the cation exchange resin made by introducing a sulfonic acid group into a divinylbenzene spherical crosslinked copolymer is used not only for water treatment but also for a wide range of applications such as amino acid purification and catalyst applications. It is used. In recent years, sulfonic acid type cation exchange resins have also begun to be used to directly adsorb and purify amino acids from fermentation liquids. When treating a solution with a relatively high content of suspended solids, such as fermentation liquor, with an ion exchange resin, the ion exchange resin column packed with ion exchange resin is treated with a downward flow as in normal water treatment. When a liquid is passed through the resin layer, suspended matter accumulates on the upper surface of the resin layer, impairing the flow of the liquid, causing an increase in the pressure of the liquid flowing through the resin layer, and often making it impossible to pass the liquid through the resin layer. In order to prevent such a phenomenon, it is possible to prevent the deposition of suspended solids by passing the solution containing suspended solids through the resin column in an upward flow and allowing the suspended solids to pass through the resin layer. . However, when such upward flow is carried out, if the specific gravity of the resin is smaller than the liquid being passed through, all of the resin will clog the upper part of the resin column, and floating suspended matter will accumulate at the bottom of the column. Similar to when liquid is passed in a downward flow, the liquid passing pressure often increases, making it impossible to pass liquid. However, conventional sulfonic acid type cation exchange resins are
Since it is a styrene-divinylbenzene copolymer into which sulfonic acid groups are introduced, its true specific gravity is also a sodium-type resin of about 1.20 to 1.35. On the other hand, in general, liquids containing floating suspensions such as fermentation liquids often contain large amounts of inorganic salts, so conventional ion exchange resins
There have been many cases in which it has been difficult to employ such an upward flow liquid method. Therefore, resins with high specific gravity suitable for such uses are required. For example, it is possible to produce cation exchange resins with high specific gravity by brominating and then sulfonating a styrene-divinylbenzene crosslinked copolymer. Already proposed. In producing such resins, the method of brominating a spherical crosslinked copolymer (see Japanese Patent Application Laid-Open No. 163993/1983) and the method of sulfonating a styrene-divinylbenzene spherical polymer are known (for example, "Experimental Methods of Polymer Synthesis": co-authored by Takayuki Otsu and Masayoshi Kinoshita, published by Kagaku Dojin Co., Ltd., 1972, 374 pages). However, when the styrene-divinylbenzene spherical crosslinked copolymer was first brominated and then sulfonated by combining the above methods, most of the resin particles were broken, and it was extremely difficult to obtain a completely spherical resin. . Considering the use of upward flow, which is one of the uses of cation exchange resins with a large specific gravity, such cracked resins tend to clog the resin tower, and there is also a large possibility of pulverization, making it difficult for the general public to use them. This is undesirable as there is an extremely high risk of pressure increase during liquid state. In view of these circumstances, the inventors of the present invention conducted intensive studies on the method for producing brominated sulfonated resins, and found that the cause of such cracks in oils and fats lies in the preparation method of the brominated copolymer. Later, they discovered that cracking or cracking could be avoided by washing the copolymer with a specific solvent, leading to the present invention. That is, the present invention provides an industrially advantageous method for producing a sulfonic acid type cation exchange resin with no cracks and a high specific gravity. After brominating the crosslinked copolymer with a brominating agent, the brominated crosslinked copolymer is washed with an aprotic polar organic solvent capable of swelling the crosslinked copolymer, and then sulfonated. A method for producing a spherical brominated sulfonic acid type cation exchange resin having a specific gravity, and a cation in which the aprotic polar organic solvent is selected from aliphatic ketones, aliphatic carboxylic acid esters, cyclic ethers, dimethylformamide, and dimethyl sulfoxide. It consists in the manufacturing method of exchange resin. The present invention will be explained in detail below. The copolymer consisting of a gel-type aromatic monovinyl monomer and a polyvinyl monomer having a three-dimensional structure used in the method of the present invention is produced by a known method (for example, the above-mentioned "Experimental method of polymer synthesis").
reference). In addition to styrene, vinyltoluene, ethylvinylbenzene, vinylnaphthalene, vinylxylene, and the like are used as the raw material aromatic monovinyl monomer. In addition, as a polyvinyl monomer,
Divinylbenzene is a typical example, but other useful compounds include aromatic polyvinyl compounds such as vinylnaphthalene and trivinylbenzene, and aliphatic polyvinyl compounds such as trimethylolpropane trimethacrylate. The amount of polyvinyl monomer relative to the aromatic monovinyl monomer can vary arbitrarily, but is generally between about 1 and 60% by weight, preferably 3 and 25% by weight of the total amount of polyvinyl monomer and monovinyl monomer.
used in equivalent amounts between These monomer mixtures are copolymerized by suspension polymerization in water according to a conventional method. During polymerization, add a radical polymerization initiator such as benzoyl peroxide, lauroyl peroxide, or azobisisoputyronitrile to the monomer in an amount of 0.05 to 10% by weight.
If necessary, gelatin, polyvinyl alcohol, magnesium silicate, etc. can also be used as a child dispersion stabilizer. The polymerization reaction is carried out at 60-100°C for 6-20 hours. The gel-type spherical crosslinked copolymer produced according to the polymerization method as described above is brominated with a brominating agent, and the bromination is mainly carried out on the aromatic rings. Specifically, bromination is carried out by converting the spherical crosslinked copolymer into elemental bromine, ferric chloride, iodine,
The reaction is carried out in the presence or absence of iron, thallium acetate, mercuric acetate, etc. at a temperature of 0 to 50°C for 1 to 20 hours. In addition to elemental bromine, sulfuryl bromide and the like are also useful as brominating agents. The amount of bromine introduced can be controlled at any ratio depending on the amount of brominating agent used, but in order to achieve high specific gravity, which is one of the objectives of the present invention, the content of bromine should be adjusted at least to the brominated polymer. is 20
% or more is preferable. The brominated crosslinked copolymer is then washed with a specific solvent according to the invention. Solvents that can be used in the present invention include aprotic polar organic solvents that can swell the brominated crosslinked copolymer, specifically ketone organic solvents such as acetone and methyl ethyl ketone, and ester organic solvents such as ethyl acetate. Examples include solvents, ether solvents such as dioxane, dimethylformamide and dimethyl sulfoxide. Although the details of the reason why cracks and cracks in the copolymer can be avoided by washing with such a solvent according to the present invention are not clear, the reason is that the copolymer has high solubility in the complex of bromine ions and bromination catalyst generated in the bromination process. It is thought that because it is a solvent, the copolymer can be effectively washed after bromination. It is also believed that the cracks and cracks occur because a complex between bromide ions and the bromination catalyst causes unnecessary cleavage of crosslinks in the subsequent sulfonation reaction. Washing of the bromination reaction mixture with such a solvent is preferably carried out by packing the bromination reaction mixture into a column and treating it with the solvent. Industrially, this is carried out by draining the reaction mixture and subsequently injecting the solvent. When washing the solvent in the column, the temperature is preferably room temperature to 80°C, and the amount of solvent used is 2 to 10°C per 1 kg of brominated resin.
It is preferable that it is above a certain degree. In this case, the flow rate is preferably 5 or less. In order to remove the bromination catalyst, hydrobromic acid and unreacted bromine remaining in the bromination mixture, it is possible to wash with water or alkali-containing water prior to solvent washing, but in some cases such treatment is , which is not very preferable because it may cause cracks or cracks in the resin. After the brominated crosslinked copolymer has been washed with a solvent according to the present invention, the solvent is removed by washing with water or drying, and then the copolymer is dried. The sulfonation of the brominated crosslinked copolymer is carried out by methods known per se. Preferably, the brominated crosslinked copolymer is swollen with dichloroethane or the like, and a sulfonating agent such as sulfur trioxide or chlorosulfonic acid is used. The amount of the sulfonating agent such as sulfur trioxide or chlorosulfonic acid used is preferably about 1 to 3 g per 1 g of the copolymer. Sulfonation is carried out at the usual temperature of 0℃~
It is carried out at 100°C, preferably 30°C to 80°C, for 3 to 20 hours. The introduction rate of sulfonic acid groups is in the range of 0.5 to 1.2 moles per mole of aromatic ring. After the reaction is completed, the sulfonated resin is thoroughly washed with water after removing the swelling agent by a method such as azeotropic distillation. As described above, according to the method of the present invention, styrene-
When producing a high specific gravity sulfonic acid type cation exchange resin by brominating a polyvinylbenzene-based crosslinked copolymer and then sulfonating it,
This is an extremely useful method industrially because it is possible to produce a perfectly spherical resin without cracks or fractures by simply washing the brominated resin with a specific organic solvent. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. Example 1 50 g of gel-type styrene-divinylbenzene spherical crosslinked polymer containing 8% divinylbenzene by weight was taken, 300 g of dichloroethane was added, and the copolymer was left to stand at room temperature for 2 hours to sufficiently swell the copolymer. . Next, 2.5 g of ferric chloride was added, and 100 g of bromine was added slowly while controlling the temperature so as not to exceed 20°C. After the addition was complete, stirring was continued at 0° C. for 12 hours. This bromination reaction mixture was transferred to another column (3 cm in diameter).
φ) and washed with acetone (1). After washing, the brominated resin was removed from the column and dried at 80°C for 8 hours. The yield of dried resin was 80.7g. Take the entire amount of this brominated resin into a four-necked flask,
After adding 100 g of dichloroethane and causing sufficient swelling, 380 g of 30% olium was added and reacted at 30°C for 12 hours. After the reaction was completed, 1000 g of water was slowly added and then heated to 90°C to distill off dichloroethane. The resin was then transferred to a column (diameter 3 cmφ) and washed sequentially with 4 parts of demineralized water, 1 part of 5% saline, 2N-HCl4, and 3 parts of demineralized water. The yield and ion exchange capacity of the resin thus obtained are shown in Table 1. Next, 500 grains of this resin were collected and observed under a microscope to determine the number of cracked balls, balls with cracks, and so-called perfect balls with no cracks observed. The results are shown in Table-2. Examples 2 to 5 The same treatment as in Example 1 was carried out except that the cleaning solvent used in Example 1, acetone, was replaced with the various solvents listed in Table 1. The results are shown in Tables 1 and 2, respectively. Comparative Examples 1 to 5 The same treatment as in Example 1 was carried out, except that the various solvents listed in Table 1 were used in place of acetone, the cleaning solvent used in Example 1. The results are shown in Table-1 and Table-2. Comparative Example 6 After the copolymer was brominated in Example 1, sulfonation treatment was carried out in the same manner as in Example 1 by further adding olium to the reaction system without separating, washing and drying the reaction mixture. Ta. The results are shown in Table-1 and Table-2.

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Claims (1)

[Scope of Claims] 1. After brominating a gel-type spherical crosslinked copolymer consisting of an aromatic monovinyl monomer and a polyvinyl monomer with a brominating agent, the crosslinked copolymer is brominated with an aprotic polar organic solvent capable of swelling the crosslinked copolymer. A method for producing a spherical brominated sulfonic acid type cation exchange resin with high specific gravity, which comprises washing a brominated crosslinked copolymer and then sulfonating it. 2 The aprotic polar organic solvent is acetone,
The manufacturing method according to claim 1, characterized in that the manufacturing method is selected from aliphatic ketones such as methyl ethyl ketone, aliphatic carboxylic acid esters such as ethyl acetate, cyclic ethers such as dioxane, dimethylformamide, and dimethyl sulfoxide.