JP2009263309A - Condensation reaction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a condensation reaction method which is excellent in both reaction efficiency and handleability, low in environmental load, and low in cost. <P>SOLUTION: The condensation reaction method is one for condensing (A) a phenol compound with (B) a carbonyl compound, wherein the condensation catalyst used is a cation exchange resin produced by a method including the following step (b): (b) the step of lowering the content of a leachable compound having a specified chemical structure to 3,000 μg or smaller per gram of a monovinylaromatic monomer and a copolymer crosslinked with a crosslinking aromatic monomer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for subjecting a phenol compound and a carbonyl compound to a condensation reaction. Specifically, the present invention relates to the above condensation reaction method which is excellent in both reaction efficiency and handling, has a low environmental load, and is low in cost.

Conventionally, a cation exchange resin has been used as a reaction catalyst for the condensation reaction of a phenol compound and a carbonyl compound, represented by the production of bisphenol A. Since there are various types of cation exchange resins and the influence on the condensation reaction is also various, a condensation reaction method designed according to the purpose has been proposed.
For example, Patent Document 1 discloses a method of catalyzing a condensation reaction using a condensation reaction catalyst using copolymer beads having a narrow droplet size distribution using a jet suspension polymerization method. . According to this, it is described that the conversion rate of the reactants to bisphenols is higher than that in the case of using the batch type suspension polymerization copolymer beads produced without being injected into the suspension medium. Yes.

Patent Document 2 discloses a method for producing bisphenol A using a finely divided and / or powdery strongly acidic ion exchange resin having an effective diameter of 0.3 mm or less.
Patent Document 3 discloses a modified sulfonic acid type cation exchange resin obtained by reacting a part of a sulfonic acid group with a sulfur-containing amine compound, and has a specific particle size and particle size distribution uniformity as a catalyst. A reactor for producing bisphenol A is disclosed.
Japanese Patent No. 3312920 JP-A-62-178532 Japanese Patent No. 2887304

However, Patent Document 1 is focused on using a jet suspension polymerization method regardless of the bead size, and there are limitations on the polymerization method and the polymerization equipment.
Patent Document 2 defines an effective diameter, and Patent Document 3 describes using a resin having a specific particle size and uniformity of particle size distribution as a catalyst, but simply improves the morphological characteristics of the particles. Therefore, there is a limit to the improvement in performance, and a technique for ensuring excellent condensation reaction efficiency is desired.

As a result of intensive investigations in view of the above problems, the present inventors have polymerized under conditions such that the amount of the monomer eluted at the polymerization stage is extremely small, and the polymerization volume average particle diameter is controlled to be smaller than before and uniform. It has been found that by bringing the coefficient close to 1.0, both the excellent condensation reaction efficiency and the handling property of the catalyst can be improved.
That is, the gist of the present invention resides in the following [1] to [5].
[1] A method of subjecting (A) a phenol compound and (B) a carbonyl compound to a condensation reaction, wherein a cation exchange resin produced by a method comprising the following step (b) is used as a condensation reaction catalyst. A condensation reaction method.
(B) A step of setting the content of the eluting compound represented by the following formula (I) to 3000 μg or less with respect to 1 g of the monovinyl aromatic monomer and the crosslinkable aromatic monomer crosslinked copolymer.

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)
[2] A method in which (A) a phenol compound and (B) a carbonyl compound are subjected to a condensation reaction, and a cation exchange resin having an oxidation TOC resistance of 5 ppm or less measured by the following method is used as a condensation reaction catalyst. The condensation reaction method characterized by the above-mentioned.
[Oxidation resistance TOC elution measurement method]
(1) The cation exchange resin is centrifuged in water at 3000 rpm for 5 minutes to drain water. 10 mL of the obtained cation exchange resin in a drained state is put into an Erlenmeyer flask, and 100 mL of ultrapure water having a TOC of 10 ppb or less is added. The Erlenmeyer flask is immersed in a water bath maintained at 40 ° C. and shaken for 20 hours, and then the supernatant is collected and its TOC value is measured. This is defined as the “initial TOC value”.
(2) In the above (1), except that 100 mL of 0.1% hydrogen peroxide solution diluted with ultrapure water having a TOC of 10 ppb or less was added instead of ultrapure water having a TOC of 10 ppb or less. Similarly, the TOC value is measured, and this is referred to as “oxidized TOC value”.
(3) The oxidation resistance TOC elution property is calculated by the following formula.
(Oxidation TOC dissolution property) = (Oxidation TOC value) − (Initial TOC value)
[3] The condensation reaction method, wherein the uniformity coefficient of the cation exchange resin is 1.5 or less.
[4] The condensation reaction method, wherein the cation exchange resin has a weight average particle diameter of 400 μm or less.
[5] The condensation reaction method including a step of obtaining the cation exchange resin by one or more methods selected from a seed polymerization method, a vibration method, and a tube reactor method.
[6] The condensation reaction method, wherein the phenol compound is phenol, the carbonyl compound is acetone, and the condensation reaction is a bisphenol A production reaction.

  According to the present invention, it is possible to provide a condensation reaction method that is excellent in both reaction efficiency and handling, has a low environmental load, and is low in cost.

Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the invention.
[1] Condensation reaction method The condensation reaction of the present invention is a method in which (A) a phenol compound and (B) a carbonyl compound are subjected to a condensation reaction.

  In the condensation reaction method of the present invention, the condensation reaction between the phenol compound and the carbonyl compound is understood to utilize strong ortho or para orientation of the phenolic hydroxyl group, particularly para orientation. Should be free of substituents at the ortho or para positions, and 4,4'-bisphenol compounds are generally preferred from the use of bisphenol compounds as condensation reaction products. Phenol compounds without any are preferred. In this case, the substituent may be any as long as it does not inhibit the ortho and para orientation of the phenolic hydroxyl group and does not sterically hinder the condensation position of the carbonyl compound. The group is a lower hydrocarbon group, for example, an alkyl group having 1 to 4 carbon atoms, and a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom.

  Specific examples of the phenol compound include unsubstituted phenol, o-cresol, m-cresol, 2,5-xylenol, 2,6-xylenol, 2,3,6-trimethylphenol, 2 , 6-di-tert-butylphenol, o-chlorophenol, m-chlorophenol, 2,5-dichlorophenol, 2,6-dichlorophenol and the like. Of these, phenol is particularly preferred.

  Specific examples of the carbonyl compound include ketones having about 3 to 10 carbon atoms such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, and acetophenone, and aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde. Kind. Of these, formaldehyde and acetone are preferred, and acetone is particularly preferred. When phenol is used as the phenol compound and acetone is used as the carbonyl compound, bisphenol A useful as a raw material for polycarbonate resin and the like can be obtained, which is particularly preferable.

In the present invention, before the phenol compound and the carbonyl compound are reacted, it is preferable to pre-treat the cation exchange resin with a phenol compound at a temperature of 40 to 110 ° C. In the case of a batch type, it is preferable to treat the cation exchange resin catalyst to be used with a phenol compound having 5 to 200 times its volume. In the case of a fixed bed flow system, it is preferable to pass a phenol compound at a liquid hourly space velocity (LHSV) of 0.1 to 50 hr ⁻¹ . By this pretreatment, even when the cation exchange resin contains water, the cation exchange resin catalyst is solvent-exchanged from water to a phenol compound and can be used for the reaction without an induction period.

The reaction method of the phenol compound and the carbonyl compound in the present invention is not particularly limited, and a raw material mixture of the phenol compound and the carbonyl compound is continuously supplied to a reactor filled with the cation exchange resin catalyst. Any of a fixed bed flow system, a fluidized bed system, and a continuous stirring system in which the reaction is performed may be used, or a batch system may be used. When the reaction is carried out in a fixed bed flow system, a fluidized bed system, or a continuous stirring system, the feed of the raw material mixture is usually LHSV 0.05 hr ⁻¹ or more, preferably 0. 2 hr ⁻¹ or more. The reaction is usually performed at 20 hr ⁻¹ or less, preferably 10 hr ⁻¹ or less. The reaction temperature is usually 40 ° C or higher, preferably 60 ° C or higher, and usually 120 ° C or lower, preferably 100 ° C or lower. When the reaction temperature is less than 40 ° C., the reaction rate tends to be slow, while when it exceeds 120 ° C., the performance of the modified cation exchange resin catalyst may be remarkably deteriorated, and by-products and colored substances also tend to increase. As a raw material supply method, for example, as described in JP-A-4-1149, a method of supplying upward from below the reactor may be used. In order to reduce the pressure loss of the resin, the reactor may be divided into a plurality of units. In the case of using the above-mentioned upward feeding method, the liquid space velocity LHSV of the raw material is usually 0.1 hr −1 or more, preferably 0.3 hr −1 or more, usually 3.0 hr −1 or less, preferably 2 0.0 hr-1 or less. If the LHSV is too large, the linear velocity of the reaction liquid is high, and therefore convection of catalyst particles and blow-through of the reaction liquid occur, and the extrusion flow is not achieved. The packed bed reactor is preferably designed so that L / D is usually 0.5 or more, preferably 1 or more, and usually 5 or less, preferably 3 or less. Here, L and D respectively indicate the length of the reaction zone and the equivalent diameter of the reaction zone (inner diameter when the reactor is a cross section).

  In this case, the molar ratio of the phenol compound to the carbonyl compound is usually 2 mol or more, preferably 4 mol or more, usually 40 mol or less, preferably 30 mol or less with respect to 1 mol of the carbonyl compound. . If the amount of the phenol compound used is less than the above range, by-products tend to increase. On the other hand, if the amount exceeds the above range, the effect is hardly changed, but rather the amount of the phenol compound to be recovered and reused increases. There is a tendency to become less economical. The separation and purification of the target bisphenol compound from the reaction mixture can be exemplified by the following examples in the case of bisphenol A, which is particularly preferable for production in the production method of the present invention.

  There is no restriction | limiting in particular in each process performed following the said reaction, For example, a well-known method is employable. A typical process will be described below as an example. Subsequent to the above reaction, in the low boiling point component separation step, the reaction mixture obtained by the reaction is separated into a component containing bisphenol A and phenol and a low boiling point component containing water, unreacted acetone, etc. produced as a by-product in the reaction. To do. In the low boiling point component separation step, it is preferable to separate the low boiling point component by distillation under reduced pressure, and the low boiling point component may contain phenol or the like. The component containing bisphenol A and phenol can further remove phenol by distillation or the like to adjust the concentration of bisphenol A to a desired concentration.

  Subsequently, a slurry containing crystals of an adduct of bisphenol A and phenol is obtained in the crystallization step. The concentration of bisphenol A, which is a component containing bisphenol A and phenol used in the crystallization step, is preferably 10 to 30% from the viewpoint of ease of handling of the resulting slurry. In addition, as a crystallization method, a method of directly cooling a component containing bisphenol A and phenol, a method of cooling by mixing other solvents such as water and evaporating the solvent, and further removing phenol and concentrating. In order to obtain an adduct having a desired purity, crystallization may be performed once or twice or more. The slurry obtained in the crystallization step is solid-liquid separated into adduct crystals and mother liquor by vacuum filtration, pressure filtration, centrifugal filtration, etc. in the recovery step, and the adduct crystals of bisphenol A and phenol are recovered. Is done.

The adduct crystals obtained in the recovery step are melted in the subsequent dephenolization step, and phenol is removed by means such as flash distillation, thin film distillation, steam stripping, etc., to obtain high purity molten bisphenol A. The removed phenol is purified as desired, and can be used for the reaction, washing of crystals of the adduct obtained in the above recovery step, and the like.
Although the obtained high-purity molten bisphenol A is solidified in the granulation step, a method of obtaining a small spherical bisphenol A prill by spraying from a nozzle and contacting with a cooling gas is preferable.

In order to prevent the accumulation of impurities in the system, at least a part of the mother liquor separated in the recovery step can be processed in the impurity treatment step. For example, it is economical to mix an alkali or acid, heat and then distill to separate light and heavy components, and use the light component for the reaction after recombination treatment with an acid catalyst or the like. However, it is preferable. Here, by purging the heavy component out of the system, accumulation of impurities can be prevented and the purity of the product can be improved. The recovery rate of bisphenol A can also be improved by crystallization after isomerization of at least a part of the mother liquor using an acid catalyst.
The low boiling point component obtained in the low boiling point component separation step can separate and recover unreacted acetone by the acetone circulation step and circulate the collected acetone to the reaction step.

[2] Condensation reaction catalyst The present invention is characterized in that a cation exchange resin is used as the condensation reaction catalyst. Hereinafter, the cation exchange resin will be described in detail.
[2-1] Cation Exchange Resin The cation exchange resin used in the present invention has a crosslinked structure skeleton obtained by copolymerization of a monovinyl aromatic monomer and a crosslinkable aromatic monomer from the viewpoint of durability and rationality of the production method. What it has is preferable. Examples of the monovinyl aromatic monomer include alkyl-substituted styrenes such as styrene, methylstyrene, and ethylstyrene, and halogen-substituted styrenes such as bromostyrene. Among these, styrene or a monomer mainly composed of styrene is preferable. Moreover, as a crosslinkable aromatic monomer, divinylbenzene, trivinylbenzene, divinyltoluene, divinylnaphthalene, divinylxylene, etc. are mentioned. Of these, divinylbenzene is preferred. Industrially produced divinylbenzene usually contains a large amount of by-product ethyl vinylbenzene (ethyl styrene), but such divinylbenzene can also be used in the present invention.
Specific examples include styrene-divinylbenzene synthetic adsorbents.

  The main forms of the cation exchange resin used in the present invention include a gel type and a porous type. When used in the condensation reaction of the present invention, the gel type is preferred from the viewpoint of the production cost of the cation exchange resin. In addition, a porous type (a porous type, a high porous type, or a macroporous type) is also preferable from the viewpoint of ensuring material diffusibility, resin durability, and strength.

  The cation exchange resin used in the present invention is usually in the shape of particles (granular). Specific shapes include various shapes such as a spherical shape, a substantially spherical shape, a polyhedral shape, and an aggregate shape, but are not particularly limited.

[2-2] Method for Producing Cation Exchange Resin As the cation exchange resin as the condensation reaction catalyst used in the present invention, a cation exchange resin produced by a method including the following step (b) is used.
(B) A step of setting the content of the eluting compound represented by the following formula (I) to 3000 μg or less with respect to 1 g of the monovinyl aromatic monomer and the crosslinkable aromatic monomer crosslinked copolymer.

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)
The method for producing a cation exchange resin of the present invention preferably includes the following steps (a) to (c), more preferably the following step (d).
(A) A step of copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer to obtain a crosslinked copolymer
(B) A step of setting the content of the eluting compound represented by the following formula (I) to 3000 μg or less with respect to 1 g of a cross-linked copolymer of a monovinyl aromatic monomer and a cross-linkable aromatic monomer.

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)
(C) Step of sulfonating a crosslinked copolymer having a content of the eluting compound of 3000 μg or less with respect to 1 g of the crosslinked copolymer.
(D) A step of removing the eluting compound represented by the following formula (II) from the sulfonated crosslinked copolymer

(In the formula (II), X represents a hydrogen atom, a halogen atom, or an alkyl group which may be substituted with a halogen atom. Y represents a hydrogen atom, a metal atom, or a quaternary ammonium group. Indicates a natural number.)
Hereinafter, each step will be described.
[2-2-1] (a) A step of copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer to obtain a crosslinked copolymer
Examples of the monovinyl aromatic monomer according to the present invention include alkyl-substituted styrenes such as styrene, methylstyrene, and ethylstyrene, and halogen-substituted styrenes such as bromostyrene. These may be used alone or in combination of two or more. Among these, styrene or a monomer mainly composed of styrene is preferable.

Examples of the crosslinkable aromatic monomer include divinylbenzene, trivinylbenzene, divinyltoluene, divinylnaphthalene, and divinylxylene. These may be used alone or in combination of two or more. Of these, divinylbenzene is preferred.
Industrially produced divinylbenzene usually contains a large amount of by-product ethyl vinylbenzene (ethyl styrene), but such divinylbenzene can also be used in the present invention.

  The use amount of the crosslinkable aromatic monomer is usually 0.5% by weight or more based on the total monomer weight, preferably 1% by weight or more, more preferably 2% by weight or more, and usually 99% by weight or less, preferably It is 18 weight% or less, More preferably, it is 14 weight% or less. As the amount of the crosslinkable aromatic monomer used increases and the degree of crosslinking increases, the oxidation resistance of the resulting cation exchange resin tends to improve. On the other hand, when the degree of crosslinking is too high, the leaching oligomers are easily removed by water washing in the subsequent step. In the case of a cation exchange resin with a high degree of crosslinking, when used as a cation exchange resin for ultrapure water, the reaction rate with impurities (metal ions, colloidal substances, amines and ammonium salts) in the raw water to be purified is high. The ion exchange efficiency tends to decrease and the purity of the treated water tends to decrease.

The copolymerization reaction of the monovinyl aromatic monomer and the crosslinkable aromatic monomer can be performed based on a known technique using a radical polymerization initiator.
As the radical polymerization initiator, one kind or two or more kinds such as dibenzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, azobisisobutyronitrile are used. It is used in a range of 05% by weight to 5% by weight.

  The polymerization mode is not particularly limited, and the polymerization can be carried out in various modes such as solution polymerization, emulsion polymerization, suspension polymerization, etc. Among them, suspension in which a uniform bead-shaped copolymer can be obtained. A polymerization method is preferably employed. The suspension polymerization method can be carried out by selecting a known reaction condition using a solvent, a dispersion stabilizer or the like generally used for the production of this type of copolymer.

The polymerization temperature in the copolymerization reaction is usually room temperature (about 18 ° C. to 25 ° C.) or more, preferably 40 ° C. or more, more preferably 70 ° C. or more, and usually 250 ° C. or less, preferably 150 ° C. or less. Preferably it is 140 degrees C or less. If the polymerization temperature is too high, depolymerization occurs at the same time, and the degree of polymerization completion is lowered. If the polymerization temperature is too low, the degree of polymerization completion will be insufficient.
The polymerization atmosphere can be carried out under air or under an inert gas, and nitrogen, carbon dioxide, argon or the like can be used as the inert gas.

Moreover, the polymerization method described in JP-A-2006-328290 is preferable because it exhibits excellent condensation reaction efficiency in the condensation reaction of the present invention.
In addition, the well-known method of obtaining the crosslinked copolymer of uniform particle diameter can also be used conveniently.
For example, methods disclosed in JP 2002-35560 A, JP 2001-294602 A, JP 57-102905 A, and JP 3-249931 A can be suitably used.

[2-2-2] (b) A step of setting the content of the eluting compound having a specific structure to 3000 μg or less with respect to 1 g of the crosslinked copolymer.
The method for producing a cation exchange resin according to the present invention includes the content of the eluting compound represented by the following formula (I) (hereinafter referred to as the content of the elution compound represented by the following formula (I)) before sulfonating the crosslinked copolymer obtained in [2-2-1]. In some cases, it is referred to as “eluting compound (I)”) at 3000 μg or less, preferably 1000 μg or less, more preferably 700 μg or less, per 1 g of the crosslinked copolymer.

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)
Here, the alkyl group of Z is a C1-C8 alkyl group normally, Preferably, they are a methyl group, an ethyl group, a propyl group, and a butyl group, More preferably, they are a methyl group and an ethyl group.
If the content of the eluting compound (I) in the cross-linked copolymer to be subjected to sulfonation is too large, it is impossible to obtain a cation exchange resin with a small amount of the eluting material in which the remaining of impurities and the generation of decomposition products are suppressed. . The content of the eluting compound (I) is preferably as low as possible, but the lower limit is usually about 0.1 μg.

The eluting compound (I) according to the present invention is an unreacted or incomplete reaction product obtained when copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer. This eluting compound (I) causes an ion exchange resin eluate at the time of product, and has a weight average molecular weight in terms of polystyrene of usually 200 or more, preferably 300 or more, and usually 1,000,000. 000 or less, preferably 100,000 or less. For example, in the case of a styrene resin, styrene dimer, styrene trimer, styrene oligomer, etc. are mentioned as low polymer components that are insufficiently polymerized, and linear polystyrene, polystyrene fine particles, etc. are mentioned as free polymer components. Moreover, as a by-product in the chain transfer reaction in the polymerization reaction, a low polymer component or a free polymer component to which a polymerization inhibitor contained in the monomer is bonded can be mentioned.
The content of the eluting compound (I) in the crosslinked copolymer can be determined, for example, by an elution test described in the Examples section described later.

The step (b) according to the present invention is performed simultaneously with the step (a) by adjusting the polymerization conditions in the step (a). Further, after the polymerization, the resulting crosslinked copolymer is washed to remove the eluting compound (I), thereby obtaining a crosslinked copolymer with a reduced content of the eluting compound.
In the case of obtaining a cross-linked copolymer having a low content of the eluting compound by adjusting the polymerization conditions in the step (a), examples of the method for adjusting the polymerization conditions include the following.

[2-2-2-1] Adjustment of polymerization temperature
As described above, if the polymerization temperature in the copolymerization reaction in the present invention is too high, depolymerization occurs at the same time, and the degree of completion of polymerization is lowered. On the contrary, if the polymerization temperature is too low, the degree of completion of polymerization becomes insufficient, and the eluting compound A crosslinked copolymer with a low content cannot be obtained. Accordingly, the polymerization temperature of the monovinyl aromatic monomer and the crosslinkable aromatic monomer is room temperature (about 18 ° C. to 25 ° C.) or higher, preferably 40 ° C. or higher, more preferably 70 ° C. or higher and 250 ° C. or lower, preferably 150 ° C. or lower. More preferably, it is adjusted appropriately within a range of 140 ° C. or less. Among these, a method of obtaining a crosslinked polymer by a high temperature polymerization reaction described in detail below is particularly preferable.

[Conditions for high-temperature polymerization reaction]
What is necessary is just to perform the high temperature polymerization reaction in part or all at the temperature of 100 degreeC or more normally. Unpolymerized monomer component (monomer) generated due to insufficient progress / completion of polymerization reaction, low polymer component (dimer, trimer, oligomer) insufficiently polymerized, free polymer component (linear polymer, polymer) From the viewpoint of ensuring that impurities such as fine particles) and by-products due to the polymerization reaction are brought into a glass transition state, it is preferable to carry out at a temperature of 110 ° C. or higher, more preferably 115 ° C. or higher, particularly 120 ° C. or higher. Specifically, the glass transition point of polystyrene is about 105 ° C. when the degree of crosslinking is 5%, and is about 108 ° C. when the degree of crosslinking is 10%. However, if the temperature is too high, it takes time to raise the temperature of the polymerization solution, the range of selection of the polymerization initiator is reduced, the production equipment becomes expensive, or more than the rise of the polymerization temperature. Since the low elution effect does not appear or the produced polymer may be modified or decomposed, the upper limit of the temperature is usually 160 ° C. or lower, preferably 150 ° C. or lower, more preferably 140 ° C. or lower.

  The time for the high temperature polymerization reaction (the time at which the temperature is 100 ° C. or higher) is usually 1 hour or longer, preferably 2 hours or longer, and usually 20 hours or shorter, preferably 10 hours or shorter, more preferably 6 hours or shorter. is there. If the time of the high temperature polymerization reaction is too short, a sufficient effect cannot be obtained, while if it is too long, the effect cannot be sufficiently exhibited because there are few remaining polymerization initiators, or the produced polymer is modified or decomposed. There is a case.

The high temperature polymerization reaction may be carried out continuously, or may be carried out intermittently in several steps with a period of 100 ° C. or less in the middle. In that case, the time which is 100 degreeC or more should just be in said range in total. However, from the viewpoint of sufficiently obtaining the above effects, it is preferable to continuously perform the high temperature polymerization reaction.
The atmosphere in the high temperature polymerization reaction is preferably as low as possible with the amount of oxygen in the polymerization reaction system being usually 5 ppm or less, particularly 3 ppm or less, and more preferably 1 ppm or less as a ratio to the total raw material monomers. In the polymerization reaction (especially radical polymerization reaction), if oxygen is present in the reaction system, the terminal radical is easily copolymerized with oxygen, so oxygen is taken into the polymerization reaction of the raw material monomer and a polymer containing a peroxide bond is formed. To do. As a result, this peroxide bond can be chemically and thermally cleaved during the resin production process, washing process, or during resin use, causing oligomer generation and elution, and this peroxide bond. Is decomposed to form decomposed products such as formaldehyde and benzaldehyde, which may cause elution. Therefore, in order to suppress the elution of such oligomers and decomposition products, it is important to keep the oxygen amount in the polymerization reaction system extremely low and maintain this state.

  In order to reduce the amount of oxygen in the reaction system, it is preferable to carry out the reaction after sufficiently replacing the gas phase in the reactor with an inert gas. Degassing methods include a method of bubbling an inert gas, a method of repeating degassing under reduced pressure, a method of replacing dissolved oxygen in a liquid phase or gas phase with an inert gas by pressurization and / or heating, etc. Can be replaced by methods known in the art. Examples of the inert gas include nitrogen gas and argon gas, and nitrogen gas is preferable.

[Number of stages of high-temperature polymerization reaction]
In the high temperature polymerization reaction, at least a part of the polymerization reaction needs to be performed at a high temperature of 100 ° C. or higher, but this high temperature polymerization reaction may be combined with a polymerization reaction at a lower temperature and performed in multiple stages.
For example, as described above, when no organic solvent is present in the reaction system (for example, in the case of producing a gel-type polymer, etc.), the conversion rate of the raw material monomer is still 100 ° C. at a low stage. When the temperature is raised above, the raw material monomer is vaporized together with water to fill the reactor, and a part of the monomer is polymerized at the lid portion of the reactor, resulting in a problem that it adheres as an aggregate. Therefore, the polymerization reaction is first carried out at a comparatively low temperature of less than 100 ° C. (this is referred to as “preliminary polymerization” as appropriate), and the monomer conversion rate is increased to a certain extent, and then the high temperature polymerization reaction of 100 ° C. or more is carried out. (This is appropriately referred to as “post-stage polymerization”).

  In this case, the temperature of the pre-polymerization is usually 50 ° C. or higher, preferably 60 ° C. or higher, more preferably 70 ° C. or higher, and usually 100 ° C. or lower, preferably 90 ° C. or lower, more preferably 85 ° C. or lower. . If the temperature of the former stage polymerization is too low, the conversion rate of the polymerizable monomer is low, which is not preferable because the amount of deposits in the latter stage polymerization increases. On the other hand, if the temperature of the pre-polymerization is too high, the amount of deposits increases, and a dimer structure or a trimer structure due to thermal polymerization peculiar to styrene is not preferable.

The time for the pre-polymerization varies depending on the half-life temperature and amount of the polymerization initiator, the polymerizability of the monomer, the degree of crosslinking of the resin, etc., but usually 2 hours or more, preferably 3 hours or more, more preferably 4 hours or more, The range is usually 24 hours or less, preferably 12 hours or less, more preferably 8 hours or less. If the prepolymerization time is too short, it is not preferable because the polymerization cannot be completed and the amount of the remaining low polymer component, free polymer component and the like cannot be reduced. In addition, if the pre-polymerization time is too long, it is not preferable because the productivity is lowered.
On the other hand, as described above, when an organic solvent is present in the reaction system (for example, when a porous polymer is produced, etc.), the above-mentioned problem that the aggregates adhere to the lid of the reactor. Therefore, the polymerization reaction may be performed in one step.

  In the condensation reaction of the present invention, a cation exchange resin that combines the production method by the high temperature polymerization reaction, and (ii) reducing the uniformity coefficient, and (ii) reducing the weight average particle diameter, which will be described later, Particularly excellent condensation reaction efficiency is exhibited. The reason for this is that, in addition to obtaining a cation exchange resin in which the eluate as impurities is reduced by the high temperature polymerization reaction, the cross-linked structure of the ion exchange resin becomes more homogeneous due to the high temperature polymerization, It was inferred that the network structure became more homogeneous. That is, (1) high-temperature polymerization promotes the polymerization reaction rate during high-temperature polymerization, so that the cross-linked structure and network structure of the resulting polyvinyl monomer are more homogeneous, and the diffusibility of the reactant during the condensation reaction is improved. (2) The polymer produced by the high-temperature polymerization method has less residual steric hindrance during the condensation reaction because the remaining vinyl groups of the non-crosslinked polyvinyl monomer unit remaining in the polymer remain evenly, (3) high temperature In the polymer produced by the polymerization method, heating the polymer above the glass transition temperature reduces the entanglement of the polymer chain, making the crosslinked structure and network structure of the resulting polyvinyl monomer more uniform and diffusion in the condensation reaction. The reason is that the structure has good properties.

[2-2-2-2] Addition of deoxygenated monomer
A deoxygenated monomer is one in which the oxygen concentration in the monomer is lower than the saturated oxygen concentration. Low polymer components (dimers, trimers, oligomers) that are insufficiently polymerized, free polymer components (linear polymers, polymer fine particles) ), And has a role to suppress the generation of by-products due to the polymerization reaction. For example, the saturated oxygen concentration of a normal styrenic monomer is about 5% to 10% by weight. In the present invention, a deoxygenated monomer having a saturated oxygen concentration of less than 5% by weight, particularly 3% by weight or less is used. Is preferred.

  Specific methods for preparing the deoxygenated monomer include a method of bubbling the monomer with an inert gas, a method of degassing the membrane, a method of circulating the inert gas in the upper gas phase of the monomer storage tank, and a column such as silica gel. The method of doing is mentioned. Alternatively, commercially available deoxygenated monomers can also be used. Among them, the method of bubbling the monomer with an inert gas is preferable, and in this case, the inert gas used is preferably nitrogen, carbon dioxide, or argon. The deoxygenated monomer is stored in an inert gas atmosphere.

  The addition amount of the deoxygenated monomer is usually 10% by weight or more, preferably 50% by weight or more, more preferably 80% by weight or more based on the total amount of the monomer mixture. If the amount of deoxygenated monomer is too small, low polymer components (dimers, trimers, oligomers) that are insufficiently polymerized, free polymer components (linear polymers, polymer fine particles), and by-products due to polymerization reactions are generated. Become more.

[2-2-2-3] Use of monomer from which polymerization inhibitor has been removed
By removing the polymerization inhibitor in the mixture of monovinyl aromatic monomer and crosslinkable aromatic monomer used in the polymerization, low polymer components (dimers, trimers, oligomers) that are insufficiently polymerized, free polymer components (line) Generation of by-products due to polymerization reaction, polymer fine particles), polymerization reaction, and the like, and a crosslinked copolymer having a low content of eluting compounds can be obtained.

[2-2-2-4] Use of a crosslinkable aromatic monomer with few impurities
Usually, in the crosslinkable aromatic monomer, for example, divinylbenzene, non-polymerizable impurities such as diethylbenzene are present, which causes the formation of the eluting compound (I). The group monomer is preferably one having a low impurity content.

  As such a crosslinkable aromatic monomer having a low impurity content, a specific grade having a crosslinkable aromatic monomer content (purity) higher than 57% by weight is preferably selected and used. In addition, a crosslinkable aromatic monomer having a small impurity content can be obtained by removing impurities by, for example, distillation.

  The crosslinkable aromatic monomer content (purity) of the crosslinkable aromatic monomer used in the present invention is particularly preferably 60% by weight or more, more preferably 80% by weight or more, and is non-polymerizable in the crosslinkable aromatic monomer. The impurity content is usually 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less per monomer weight. If this impurity content is too high, it tends to cause a chain transfer reaction to impurities during polymerization, so the amount of eluting oligomer (polystyrene) remaining in the polymer after polymerization may increase, and the eluting compound content A small amount of a crosslinked copolymer cannot be obtained.

[2-2-2-5] Adjustment of use amount of crosslinkable aromatic monomer
As described above, the more the crosslinkable aromatic monomer used for copolymerization, the more the oxidation resistance of the resin tends to be improved. On the other hand, if the degree of crosslinking is too high, removal of the eluting oligomer in the subsequent step is incomplete. The amount of the crosslinkable aromatic monomer used is usually 0.5% by weight or more, preferably 1% by weight or more, based on the total monomer weight, because it is easy to obtain a crosslinked copolymer with a low content of the eluting compound. More preferably, it is 2% by weight or more, usually 99% by weight or less, preferably 18% by weight or less, and more preferably 14% by weight or less. Adjust appropriately within the range.
In addition, when the step (b) is performed after the step (a), the following cleaning step can be employed.

[2-2-2-6] Step of washing the crosslinked copolymer
In the present invention, if necessary, the cross-linked copolymer produced from the monovinyl aromatic monomer and the cross-linkable aromatic monomer in the step (a) is used with a solvent before the later-described (c) sulfonation step. The eluting compound (I) can be removed by washing.

This washing method can be carried out by a column method in which a crosslinked copolymer is packed in a column and a solvent is passed, or by a batch washing method.
The washing temperature is usually room temperature (20 ° C) or higher, preferably 30 ° C or higher, more preferably 50 ° C or higher, particularly preferably 90 ° C or higher, and usually 150 ° C or lower, preferably 130 ° C or lower, more preferably 120 ° C or lower. It is. If the washing temperature is too high, the cross-linked copolymer will be decomposed. If the washing temperature is too low, the washing efficiency is lowered.

The contact time with the solvent is usually 5 minutes or longer, preferably 1 hour or longer, more preferably 2 hours or longer, and usually 4 hours or shorter. If the contact time with the solvent is too short, the cleaning efficiency is lowered, and if the time is too long, the productivity is lowered.
Solvents used for washing include aliphatic hydrocarbons having 5 or more carbon atoms, such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, and the like; alcohols such as methanol, Ethanol, propanol, butanol, etc .; ketones such as acetone, methyl ethyl ketone, etc .; ethers such as dimethyl ether, diethyl ether, methylal, etc .; chlorinated solvents such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, etc .; phenols such as Such as phenol, and the like. These may be used alone or in combination of two or more. Of these, benzene, toluene, xylene, acetone, diethyl ether, methylal, dichloromethane, chloroform, dichloroethane, and trichloroethane are preferable. Further, a method of mixing these solvents with water, raising the temperature, and washing in an azeotropic state can also be employed.

[2-2-3] (c) Step of sulfonating the crosslinked copolymer
The crosslinked copolymer obtained through the steps of [2-2-1] and [2-2-2] is then sulfonated to introduce ion exchange groups according to a known method.
For example, as a method for introducing a sulfonic acid group, methods described in JP-A-5-132565, JP-T-10-508061, and the like are used.

[2-2-4] (d) A step of removing an eluting compound having a specific structure from a sulfonated crosslinked copolymer (sulfonated crosslinked copolymer)
In the present invention, the sulfonated cross-linked copolymer obtained in [2-2-3] is then referred to as an eluting compound represented by the following formula (II) (hereinafter referred to as “eluting compound (II)”). In some cases, the content of the eluting compound (II) is preferably 10,000 μg or less, more preferably 5,000 μg or less, particularly 1 mL of the sulfonated crosslinked copolymer. It is preferable to purify the sulfonated cross-linked copolymer so that the amount is preferably 1,000 μg or less, particularly preferably 100 μg or less. When the content of the eluting compound (II) is large, it is not possible to obtain a cation exchange resin with a small amount of the eluting material in which the remaining of impurities and the generation of decomposition products are suppressed. The smaller the content of the eluting compound (II), the better.

(In the formula (II), X represents a hydrogen atom, a halogen atom, or an alkyl group which may be substituted with a halogen atom. Y represents a hydrogen atom, a metal atom, or a quaternary ammonium group. Indicates a natural number.)
Here, the alkyl group which may be substituted with the halogen atom of X is usually an alkyl group having 1 to 10 carbon atoms or a haloalkyl group, preferably a methyl group, an ethyl group, a propyl group, a butyl group, a halomethyl group. , A haloethyl group, a halopropyl group, and a halobutyl group, and more preferably a methyl group, an ethyl group, a halomethyl group, and a haloethyl group.

Examples of the metal atom of Y include cation metals such as sodium, calcium, potassium, iron, zinc, lead, aluminum, manganese, and nickel.
In addition, the said elution compound (II) based on this invention causes the elution thing of the ion exchange resin at the time of a product similarly to the said elution compound (I). The breakdown includes substances derived from the eluting compounds originally contained in the cross-linked copolymer which is the base of sulfonation, and substances generated at the stage of sulfonation.

The substance derived from the eluting compound originally contained in the cross-linked copolymer that is the base of the sulfonation is a sulfonated compound of the eluting compound (I) described in [2-2-2] (b), and It corresponds to the substance represented by the formula (II). Also included are substances into which a plurality of sulfone groups are introduced.
Examples of the substance generated in the sulfonation stage include substances caused by oxidation during sulfonation, which is also represented by the above formula (II). For example, low-molecular and high-molecular polymers and oligomer components generated by cleavage of the main chain of the crosslinked copolymer.

  The weight average molecular weight of these eluting compounds (II) in terms of polystyrene sulfonic acid is usually 200 or more, preferably 300 or more, and usually 1,000,000 or less, preferably 100,000 or less. For example, in the case of a styrene resin, the eluting compound (II) is a styrene dimer, styrene trimer, sulfonated styrene oligomer or the like as a low polymer component that is insufficiently polymerized, and linear polystyrene or polystyrene fine particles as a free polymer component. Examples include sulfonated products. Further, as a by-product in the chain transfer reaction in the polymerization reaction, a low polymer component combined with a polymerization inhibitor contained in the monomer and a sulfonated product of a free polymer component can be mentioned.

Such eluting compound (II) can be removed, for example, by washing the sulfonated crosslinked copolymer obtained in step (c) with water and / or an organic solvent.
This washing method can be performed by a column system in which a sulfonated cross-linked copolymer is packed in a column and an organic solvent and / or water is passed through, or a batch washing method.

The washing temperature is usually room temperature (20 ° C) or higher, preferably 30 ° C or higher, more preferably 50 ° C or higher, particularly preferably 90 ° C or higher, and usually 150 ° C or lower, preferably 130 ° C or lower, more preferably 120 ° C or lower. It is. If the washing temperature is too high, the polymer is decomposed and the sulfone group is removed. If the washing temperature is too low, the washing efficiency is lowered.
The contact time with water and / or an organic solvent is usually 5 minutes or longer, preferably 1 hour or longer, more preferably 2 hours or longer, and usually 4 hours or shorter. If the contact time is too short, the cleaning efficiency is lowered, and if the time is too long, the productivity is lowered.

Examples of the organic solvent used for washing include aliphatic hydrocarbons having 5 or more carbon atoms such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and diethylbenzene; alcohols such as Methanol, ethanol, propanol, butanol, etc .; Ketones, such as acetone, methyl ethyl ketone, etc .; Ethers, such as dimethyl ether, diethyl ether, methylal, etc .; Chlorine solvents, such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, etc .; Phenols , For example, phenol and the like. These may be used alone or in combination of two or more. Of these, water, methanol, ethanol, propanol, toluene, and methylal are preferable.
The cation exchange resin of the present invention can be obtained by one or more methods selected from, for example, a seed polymerization method, a vibration method, and a tube reactor method. Hereinafter, each method will be described in detail.

  “Seed polymerization method (seed-feed (seed-feed) method)” uses seed particles with a small particle diameter (1 μm to several hundred μm) prepared in advance by a dispersion polymerization method. This is a technique for producing polymer particles having a larger particle size by impregnating particles with a large amount of monomer by a dynamic swelling method to form large monomer swollen particles and polymerizing the particles. The cation exchange resin produced by such a seed polymerization method, the seed polymerization method is an efficient technique for producing a large number of polymer particles having a desired particle size, and the degree of crosslinking of the resulting resin. It is preferable in the condensation reaction method of the present invention in that the network structure can be controlled to be uniform. As the seed polymerization method, for example, methods described in documents such as US Pat. No. 4,564,644, JP-A-61-16902, and JP-T-10-508061 can be used.

  The vibration method is as follows: (1) A monomer layer composed of a polymerizable monomer having laminar flow characteristics is suspended in a liquid and a stabilizing amount that are immiscible with the polymerizable monomer or monomer phase through an opening such as a nozzle or an orifice. By making it flow into a continuous phase composed of a dispersant, a monomer jet flow of a monomer layer made of a polymerizable monomer having laminar flow characteristics is formed. (2) The monomer jet flow is excited by vibrationally exciting the jet flow. Crushed into droplets, (3) these droplets are raised at a free rise rate or lowered at a free fall rate, transferred to a batch polymerization tank without substantial polymerization of the monomer, and (4) then suspended. In this method, the polymerization is carried out under conditions that do not cause the turbid monomer to coalesce, adhere, or stick.

In this vibration method, a method using an ultrasonic wave or a piezoelectric element is preferable as a means for exciting vibration in order to break the monomer jet flow from the orifice into small droplets. There are various methods for evenly propagating vibration. For example, a method of applying vibration to the entire apparatus, a method of applying vibration to the monomer, a method of applying vibration to the orifice plate, and the polymerizable monomer or monomer phase There is a method of applying vibration to a continuous phase composed of an immiscible liquid and a stabilizing amount of a suspension dispersant, and any of them can be preferably used. Examples of these vibration methods include Japanese Patent No. 2715029, Japanese Patent Publication No. 7-62045, Japanese Patent Application Laid-Open No. 5-194611, Japanese Patent Publication No. 2007-44654 as an ultrasonic vibration method, Japanese Patent Application Laid-Open No. 2007-44654, and orifices. Japanese Patent Application No. 2000-219991 and Japanese Patent Application No. 2000-1111587 as the excitation method, and Japanese Patent Application Laid-Open No. 2000-310645 as a method of using the piezoelectric element. In addition to the nozzle and the orifice, a method of passing the packed bed apparatus is also preferable for the portion where the monomer is ejected. For example, JP-T-2007-515392 is exemplified.
The cation exchange resin produced by this vibration method is preferable in the condensation reaction method of the present invention in that it is an efficient technique for producing a large number of polymer particles having a desired particle size.

  The tube reactor method is (1) a liquid in which a monomer layer composed of a polymerizable monomer having laminar flow characteristics is not miscible with the polymerizable monomer or the monomer phase through an opening such as a nozzle, and a stabilizing amount of a suspension dispersant. To form a monomer jet flow of a monomer layer made of a polymerizable monomer having laminar flow characteristics. (2) By exciting this jet flow vibrationally, droplets of the monomer jet flow are formed. (3) The droplets are raised at a free rise rate or lowered at a free fall rate and introduced into a tubular reactor without substantial polymerization of the monomer, (4) and then suspended. In this method, the polymerization is carried out under conditions that do not cause the turbid monomer to coalesce, adhere, or stick.

In the case of such a tube reactor method, the polymerization can be started in a tubular reactor immediately after the monomer jet stream is broken into small droplets, so that the productivity is excellent. On the other hand, when polymerizing in a batch polymerization tank, when feeding monomer droplets to the batch polymerization tank, it is necessary to feed until a predetermined amount is stored in the polymerization tank, which takes time.
In the case of the tube reactor method, since the polymerization can be started in the tubular reactor immediately after the monomer jet stream is broken into small droplets, it is not necessary to maintain the suspension dispersibility of the generated droplets for a long time. . As a result, since the amount of the suspension dispersant added to the continuous phase can be reduced, the cost can be reduced and the load of the step of removing the suspension dispersant after polymerization can be reduced.

For these reasons, an ion exchange resin produced by a tube reactor method is preferred in the condensation reaction method of the present invention. As the tube reactor method, for example, methods such as JP2008-7668 and non-patent literature (Macromol. Symp. 2006, 245-246, 398-402.) Can be employed.

[2-3] Oxidation TOC Elution Resistance The cation exchange resin as a condensation reaction catalyst used in the present invention is characterized by an oxidation TOC elution resistance measured by the following method of 5 ppm or less.
[Oxidation resistance TOC elution measurement method]
(1) The cation exchange resin is centrifuged in water at 3000 rpm for 5 minutes to drain water. 10 mL of the obtained cation exchange resin in a drained state is put into an Erlenmeyer flask, and 100 mL of ultrapure water having a TOC of 10 ppb or less is added. The Erlenmeyer flask is immersed in a water bath maintained at 40 ° C. and shaken for 20 hours, and then the supernatant is collected and its TOC value is measured. This is defined as the “initial TOC value”.
(2) In the above (1), except that 100 mL of 0.1% hydrogen peroxide solution diluted with ultrapure water having a TOC of 10 ppb or less was added instead of ultrapure water having a TOC of 10 ppb or less. Similarly, the TOC value is measured, and this is referred to as “oxidized TOC value”.
(3) The oxidation resistance TOC elution property is calculated by the following formula.
(Oxidation TOC dissolution property) = (Oxidation TOC value) − (Initial TOC value)

[2-4] Weight average particle diameter The weight average particle diameter of the cation exchange resin used in the present invention is usually 400 µm or less, preferably 350 µm or less, more preferably 250 µm or less, and usually 100 µm or more. If the weight average particle diameter is too large, the reaction activity tends to decrease, and if it is too small, the pressure loss tends to increase when the reaction liquid flows in the reactor. As described above, when a cation exchange resin having a weight average particle size in the above range is produced using the above-described high temperature polymerization reaction, the reaction efficiency of the condensation reaction of the present invention is further excellent.

The weight average particle diameter is measured and calculated by the following measurement method.
<Weight average particle size measurement method>
The sieves having a sieve mesh diameter of 1180 μm, 850 μm, 710 μm, 600 μm, 425 μm, and 300 μm are stacked so that the sieve mesh diameter decreases as it goes downward. This stacked sieve is placed on a vat, and about 100 mL of cation exchange resin is put into a 1180 μm sieve stacked on the top.

  Gently pour water onto the resin from a rubber tube connected to tap water and screen the small particles downward. The cation exchange resin remaining in the 1180 μm sieve is further screened for small particles by the following method. That is, water is filled up to a depth of about 1/2 of another bat, and a 1180 μm sieve is repeatedly shaken by giving up and down and rotational motion in the bat, and small particles are sieved.

  The small particles in the vat are returned to the next 850 μm sieve, and the cation exchange resin remaining on the 1180 μm sieve is collected in another vat. If the cation exchange resin is clogged in the sieve, place the sieve in the vat reversely, closely contact the rubber tube connected to the tap water, and take out the cation exchange resin clogged with the water by strongly flowing water. The cation exchange resin taken out is transferred to the bat where the cation exchange resin remaining on the 1180 μm sieve is collected, and the volume is measured with a graduated cylinder. Let this volume be a (mL). The cation exchange resin that passed through the 1180 μm sieve was subjected to the same operation for the 850 μm, 710 μm, 600 μm, 425 μm, and 300 μm sieves, respectively, and the volume b (mL), c (mL), d (mL), e (mL) and f (mL) are obtained, and finally, the volume of the resin that has passed through the 300 μm sieve is measured with a graduated cylinder to be g (mL).

V = a + b + c + d + e + f + g, a / V × 100 = a ′ (%), b / V × 100 = b ′ (%), c / V × 100 = c ′ (%), d / V × 100 = d ′ ( %), E / V × 100 = e ′ (%), f / V × 100 = f ′ (%), g / V × 100 = g ′ (%).
From the above a ′ to g ′, the residual amount cumulative (%) of each sieve is taken on one axis, and the diameter (mm) of the sieve mesh is taken on the other axis, and this is plotted on the logarithmic probability paper. Take 3 points in the order of the remaining amount, draw a line that satisfies these 3 points as much as possible, obtain the diameter (mm) of the sieve mesh corresponding to 50% of the accumulated residue from this line, and calculate the weight average The particle size.

In addition, the calculation method of the said weight average particle diameter is described, for example in Mitsubishi Chemical Corporation ion exchange resin division "Diaion I basics edition" 14th edition (September 1, 1999) pp.139-141. This is a known calculation method.
The anion exchange resin of the present invention having the above weight average particle diameter can be obtained by, for example, a known classification method. As the classification method, classification using a sieve, a water sieve using a water stream, a wind sieve using an air stream, and the like can be used.

[2-5] Uniformity coefficient The cation exchange resin used in the present invention preferably has a sharp particle size distribution, and the uniformity coefficient shown by the following calculation method is usually 1.5 or less, preferably 1.4 or less, Preferably it is 1.3 or less. Moreover, it is 1.0 or more normally. It is preferable that the uniformity coefficient is within such a range in that the reaction activity is improved and the pressure loss during liquid passage is reduced. A smaller uniformity coefficient is desirable, but if it is too large, the reaction activity tends to decrease.
As described above, when a cation exchange resin having a small uniformity coefficient is produced using the above-described high-temperature polymerization reaction, the reaction efficiency of the condensation reaction of the present invention is further excellent.

<Uniformity coefficient measurement method>
A cation exchange resin sieved by the above-mentioned weight average particle diameter measuring method is used. On the logarithmic probability paper, plot the cumulative residual amount (%) of each sieve of a ′ to g ′ and the diameter (mm) of the corresponding sieve mesh, and select 3 points in order of the residual content from among them. Draw a straight line that satisfies the three points as much as possible. From this straight line, the diameter (mm) of the sieve mesh corresponding to 90% of the accumulated residue is obtained, and this is set as the effective diameter. Next, the diameter (mm) of the sieve mesh corresponding to the residual amount of 40% is obtained, and the uniformity coefficient is obtained by the following equation.

Uniformity coefficient = [diameter of sieve mesh corresponding to 40% cumulative residue (mm)] / [effective diameter (mm)]
In addition, the calculation method of the said uniform grain coefficient is described in Mitsubishi Chemical Corporation ion exchange resin division "Diaion I basics edition" 14th edition (September 1, 1999) pp. 139-141, for example. This is a known calculation method.
As the classification method, classification using a sieve, a water sieve using a water stream, a wind sieve using an air stream, and the like can be used. Further, the cation exchange resin of the present invention having the above-mentioned uniformity coefficient can also be obtained by the uniform particle size production technique described in Japanese Patent Application No. 63-0116916.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.
[Example 1]
1800 mL of demineralized water was placed in a 3 liter separable flask, and 33 mL of a 6 wt% aqueous solution of polyvinyl alcohol (for industrial use, manufactured by Nippon Synthetic Chemical Co., Ltd.) was added and dissolved to prepare an aqueous phase. In this aqueous phase, 620 g of styrene (industrial grade, manufactured by Idemitsu), 36 g of divinylbenzene (industrial grade, purity 63% by weight, manufactured by Dow), dibenzoyl peroxide (purity 75% by weight, wet product, manufactured by NOF Corporation) 1 .8 g and a mixture of 2.0 g of t-butylperoxy-2-ethylhexyl monocarbonate (purity 99% by weight, manufactured by NOF Corporation) were added and suspended by stirring. The suspension was kept at 80 ° C. for 5 hours with stirring, and then reacted at 120 ° C. for 4 hours to obtain a copolymer (1).
The amount of elution polystyrene was quantified by the following procedure (B) with respect to the obtained crosslinked copolymer.

Procedure (B) Elutable polystyrene amount 1) 1 part of a cross-linked copolymer is placed in an Erlenmeyer flask.
2) Add 5 times amount of tetrahydrofuran (grade for high performance liquid chromatography manufactured by Wako Pure Chemical Industries).
3) Hold at 40 ° C. for 5 hours.
4) Mix the obtained tetrahydrofuran supernatant and water in a ratio of 1: 7.
5) The turbidity of the obtained solution is measured by the UV method, and the amount of elution polystyrene is determined based on the calibration curve of the tetrahydrofuran solution of the polystyrene sample measured by the same method.

  120 parts of the copolymer was put into a reactor, and 180 parts of nitrobenzene (a Wako Pure Chemicals reagent) was added to sufficiently swell the copolymer. Thereafter, 660 parts of 98% sulfuric acid (special grade manufactured by Kishida Chemical Co., Ltd.) was added, and the reaction was conducted by heating at 73 ° C. for 5 hours and at 100 ° C. for 1 hour while stirring in an oil bath. Thereafter, it was diluted with dilute sulfuric acid and demineralized water to obtain a cation exchange resin.

  The obtained cation exchange resin was adjusted in particle size by sieving so that the average particle size was 366 μm and the uniformity coefficient was 1.1. The average particle diameter and uniformity coefficient of the obtained resin and bisphenol A (BPA) catalytic activity were evaluated, and the results are shown in Table-1.

[Bisphenol A (BPA) catalytic activity evaluation]
3.0 g of cation exchange resin was weighed in a four-necked flask equipped with a reflux tube and a stirring blade. Next, after adding phenol and stirring for 10 minutes, the supernatant liquid of phenol was extracted with an ejector, and the operation was repeated three times. Thereafter, phenol was charged to 90 g, maintained at 70 ° C., and 4.3 g of acetone was added to start the reaction. Supernatant was collected at predetermined time intervals in a sample bottle, diluted with tetrahydrofuran, and then analyzed for bisphenol A conversion by gas chromatography.

[Oxidation-resistant TOC dissolution test]
The oxidation resistance TOC elution property of the ion exchange resin was evaluated by the following formula by measuring “initial TOC value” and “oxidation TOC value” as follows.
(Oxidation TOC dissolution property) = (Oxidation TOC value) − (Initial TOC value)
The initial TOC value was based on the method specified below.

[Initial TOC value measurement method]
The ion exchange resin to be measured was drained by a centrifugal technique in a wet state. 10 mL of the obtained ion exchange resin in a drained state was put into an Erlenmeyer flask, and 100 mL of ultrapure water having a TOC of 10 ppb or less was added. After shaking at 40 ° C. for 20 hours, the supernatant was collected and its TOC value was measured with Shimadzu TOC-5000A, which was used as the initial TOC value.

[Oxidation TOC value measurement method]
The ion exchange resin to be measured was drained by a centrifugal technique in a wet state. 10 mL of the obtained ion exchange resin in a drained state was placed in an Erlenmeyer flask, and 100 mL of 0.1% hydrogen peroxide diluted with ultrapure water of TOC 10 ppb or less was added. After shaking at 40 ° C. for 20 hours, the supernatant was collected and its TOC value was measured with Shimadzu TOC-5000A, which was defined as the oxidized TOC value.

[Comparative Example 1]
To 2220 parts of demineralized water, 34 parts of a 6% by weight aqueous solution of polyvinyl alcohol (for industrial use, manufactured by Nippon Synthetic Chemical) was added and dissolved to prepare an aqueous phase. In this aqueous phase, 380 parts of styrene (industrial grade, manufactured by Idemitsu Co., Ltd.), 29 parts of divinylbenzene (industrial grade, purity 57% by weight, manufactured by Nippon Steel Chemical Co., Ltd.), dibenzoyl peroxide (purity 75% by weight, wet product, manufactured by NOF Corporation) ) 0.7 parts mixed liquid was added and stirred to suspend. The suspension was kept at 80 ° C. for 5 hours with stirring, and then reacted at 120 ° C. for 4 hours to obtain a copolymer (1).

The amount of elution polystyrene was quantified by the procedure (B) described in Example 1 for the obtained crosslinked copolymer.
The copolymer was converted into a cation exchange resin in the same procedure as in Example 1.
The average particle diameter and uniformity coefficient of the obtained resin and bisphenol A (BPA) catalytic activity evaluation were carried out, and the results are shown in Table-1.

[Comparative Example 2]
The particle size of the cation exchange resin produced in Comparative Example 1 was adjusted to a uniformity coefficient of 1.06 at 710 μm, and then the BPA catalyst activity was evaluated. Moreover, the oxidation-resistant TOC test was also conducted and the results are shown in Table 1.

[Comparative Example 3]
The cation exchange resin produced in Comparative Example 1 was subjected to BPA catalyst activity evaluation after adjusting the particle size to a uniformity coefficient of 1.1 at 380 μm by sieving. Moreover, the oxidation-resistant TOC test was also conducted and the results are shown in Table 1.

  As is clear from comparison of the BPA yield values in Table 1, the cation exchange resins obtained in the present invention are both high yields and less elution than the resins obtained by the conventional method. Also excellent in terms.

Claims (6)

A condensation reaction comprising (A) a phenol compound and (B) a carbonyl compound, wherein a cation exchange resin produced by a method comprising the following step (b) is used as a condensation reaction catalyst. Method.
(B) A step of setting the content of the eluting compound represented by the following formula (I) to 3000 μg or less with respect to 1 g of the monovinyl aromatic monomer and the crosslinkable aromatic monomer crosslinked copolymer.

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.) A method of condensing (A) a phenol compound and (B) a carbonyl compound, wherein a cation exchange resin having an oxidation TOC resistance of 5 ppm or less measured by the following method is used as a condensation reaction catalyst. A condensation reaction method.
[Oxidation resistance TOC elution measurement method]
(1) The cation exchange resin is centrifuged in water at 3000 rpm for 5 minutes to drain water. 10 mL of the obtained cation exchange resin in a drained state is put into an Erlenmeyer flask, and 100 mL of ultrapure water having a TOC of 10 ppb or less is added. The Erlenmeyer flask is immersed in a water bath maintained at 40 ° C. and shaken for 20 hours, and then the supernatant is collected and its TOC value is measured. This is defined as the “initial TOC value”.
(2) In the above (1), except that 100 mL of 0.1% hydrogen peroxide solution diluted with ultrapure water having a TOC of 10 ppb or less was added instead of ultrapure water having a TOC of 10 ppb or less. Similarly, the TOC value is measured, and this is referred to as “oxidized TOC value”.
(3) The oxidation resistance TOC elution property is calculated by the following formula.
(Oxidation TOC dissolution property) = (Oxidation TOC value) − (Initial TOC value)   The condensation reaction method according to claim 1 or 2, wherein the uniformity coefficient of the cation exchange resin is 1.5 or less.   The condensation reaction method according to any one of claims 1 to 3, wherein the cation exchange resin has a weight average particle diameter of 400 µm or less.   The condensation reaction method according to any one of claims 1 to 4, further comprising a step of obtaining the cation exchange resin by one or more methods selected from a seed polymerization method, a vibration method, and a tube reactor method.   The condensation reaction method according to claim 1, wherein the phenol compound is phenol, the carbonyl compound is acetone, and the condensation reaction is a bisphenol A production reaction.