JPS5812895B2 - Method for producing polymers having halogenated methyl groups - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polymer having a methyl rogenation group.

Traditionally, anion exchange resins are most commonly prepared by reacting a base polymer with an aromatic nucleus with a haloalkyl ether such as chloromethyl ether using a Friedel-Crafts catalyst in the presence or absence of a suitable swelling agent. The haloalkylated polymer is produced by reacting the haloalkyl group with a suitable amine.

However, this method has a problem in that it uses potentially harmful halogen-containing compounds such as chloromethyl ether, and recently, methods for producing anion exchange resins that do not use such haloalkyl ethers have been studied.

One method for producing anion exchange resins that does not use haloalkyl ethers is to use a monomer that has both a polymerizable unsaturated bond and a halogenated methyl group in its aromatic nucleus, such as chloromethylstyrene, to form a polyfunctional vinyl such as divinylbenzene. A method is known in which a halomethylated polymer is copolymerized with a monomer and the resulting halomethylated polymer is reacted with an appropriate amine.

In the conventional universal method of introducing a functional group into a base polymer having an aromatic nucleus, if a crosslinking agent having an aromatic nucleus such as divinylbenzene is used, a functional group can also be introduced into the aromatic nucleus involved in the crosslinked structure. Therefore, the amount of ion exchange per unit area of the product is relatively small.

On the other hand, the method of copolymerizing a halomethyl-substituted aromatic monomer such as chloromethylstyrene with a crosslinking agent such as divinylbenzene has the disadvantage that the content of functional groups decreases by the amount of crosslinking monomer used.

If the amount of crosslinking monomer used is reduced in order to maintain the content of functional groups at a certain level (in other words, the degree of crosslinking is lowered)
, the mechanical strength of the produced ion exchange resin deteriorates, and therefore there are natural restrictions on reducing the amount of crosslinking monomer used.

The present inventors have conducted extensive research to solve the above problems, and have completed the present invention.

An object of the present invention is to provide a method for producing a polymer having a halogenated methyl group, which has a high functional group density per unit area and the functional resin derived therefrom has excellent performance. The purpose of this is to copolymerize a monomer having a polymerizable unsaturated bond and a halogenated methyl group in the aromatic nucleus with a polyfunctional vinyl monomer according to the present invention, and then add both of the above monomers to the thus obtained crosslinked copolymer to absorb the monomer. This is achieved by repeatedly carrying out polymerization.

As described above, the present invention involves copolymerizing a monomer having at least a polymerizable unsaturated bond and a halogenated methyl group in its aromatic nucleus, for example, chloromethylstyrene and a polyfunctional vinyl monomer such as divinylbenzene. Once a crosslinked polymer is produced with a certain degree of crosslinking, a mixture of both monomers is added to the previously produced crosslinked polymer and absorbed, polymerization is carried out again, and this operation is repeated as many times as necessary.

When producing an anion exchange resin, the final product obtained as described above may be reacted with a suitable amine.

The resin thus obtained is an ion-exchange product obtained by aminating the polymer obtained by polymerizing in the first stage the same monomer composition ratio in all stages including the first stage polymer or both monomers added in the latter stage. It exhibits an apparently higher degree of crosslinking than resin, and has a larger ion exchange capacity per unit volume.

For ion exchange resins, when the skeletal structure of the resin matrix and the type of exchange group are the same, there is a certain correlation between the degree of crosslinking (expressed by the content of crosslinking agent in the copolymer) and the moisture content of the wet resin. As the degree of crosslinking increases, the moisture content of the wet resin decreases.

Ion-exchange resins made from polymers obtained by multi-stage polymerization according to the present invention have the same degree of crosslinking (same amount of cross-linking ), the moisture content of the wet resin is low, the ion exchange capacity per unit volume is high, and the mechanical properties are good.

Therefore, in terms of moisture and mechanical properties, the effect is similar to that of increasing the degree of crosslinking (increasing the amount of crosslinking agent used).

In this book, this phenomenon is expressed as ``apparently high degree of crosslinking.''

When attempting to obtain an ion exchange resin from one obtained by multi-stage polymerization according to the method of the present invention from one obtained by one-stage polymerization,
Since the amount of crosslinking agent must be increased, the exchange capacity per unit volume is inevitably reduced.

It is not necessarily clear why the above-mentioned effects of the method of the present invention are produced, but it is because the polymer obtained by multi-stage polymerization has a denser structure than that obtained by one-stage polymerization. It is speculated that this is the case.

Examples of the monomer having a polymerizable unsaturated bond and a halogenated methyl group used in the method of the present invention include p-chloromethylstyrene, m-chloromethylstyrene, chloromethylvinylnaphthalene, and mixtures thereof.

Further, examples of the polyfunctional vinyl monomer used in the method of the present invention include divinylbenzene, divinyltoluene, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate.

The amount of this substance to be used is selected from the range of 0.1 to 20% by weight, preferably 0.5 to 10%.

The first stage polymerization is carried out by selecting an appropriate suspension stabilizer from among polyvinyl alcohol, gelatin, and other known suspension stabilizers, and performing so-called pearl polymerization or other suspension polymerization using water as a dispersion medium. is suitable.

Polymerization is carried out according to a conventional method using a polymerization initiator such as benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, or the like.

The amount of polymerization initiator used is 0.01 to 5% based on the monomer.
It is.

The reaction temperature is 50 to 120'C, and the reaction time is about 5 to 20 hours.

The vinyl monomer, crosslinking agent, and polymerization initiator used in the second stage polymerization are selected from those listed above, but they do not necessarily have to be the same as those in the first stage polymerization, and different monomers, different crosslinking agents, and different polymerization initiators are used. may be used in different concentrations.

The amount of monomer used in the second-stage polymerization varies depending on the swelling performance of the polymer obtained in the first-stage polymerization and the properties of the desired resin, but in general, the larger the amount, the more effective it is in increasing the "apparent degree of crosslinking." becomes.

The amount used in the subsequent polymerization is 5 to 150% by weight, preferably 20 to 70% by weight of the base resin obtained in the first stage.

In the latter stage polymerization, the base polymer is dispersed in a dispersion medium such as water, a vinyl monomer, a crosslinking agent, and a polymerization initiator are added to the base polymer, and the polymer is sufficiently absorbed into the base before being heated and polymerized.

The number of repetitions of the subsequent polymerization can be selected as appropriate depending on the purpose, as the "apparent degree of crosslinking" increases as the number increases.
Generally, a sufficient effect can be achieved by repeating the procedure once or twice.

Various ion exchange resins can be obtained by reacting the halomethylated aromatic crosslinked polymer thus obtained with a suitable amine.

The amines used are monoamines such as methylamine, dimethylamine, and trimethylamine; polyalkylene polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, and propylene diamine; aromatic amines such as pyridine; cyclic amines such as piperidine and piperazine; dimethylethanolamine , and amino alcohols such as diethanolamine.

The reaction between the amine and the halomethyl-substituted aromatic crosslinked polymer is carried out according to known methods.

The halomethyl-substituted aromatic crosslinked polymer produced by the method of the present invention is not only reacted with an amine to form an ion exchange resin, but also converted into other so-called functional polymers using highly reactive haloalkyl groups.

For example, when crosslinked polychloromethylstyrene is reacted with hydroquinone, naphthoquinone, trihydroxybenzene, etc., so-called crosslinked polyvinylbenzylhydroquinone, crosslinked polyvinylbe/zilnaphthoquinone, crosslinked polyvinylbenzyltrihydroxybenzene, etc. are produced which have oxidizing and reducing functions. What is called a redox resin is obtained.

Further, a product obtained by reacting crosslinked polychloromethylstyrene with iminodiacetic acid is known as a chelate exchange resin having high selectivity for heavy metals.

The halomethyl-substituted aromatic polymer produced by the method of the present invention can be applied not only to anion exchange resins but also to the production of other so-called functional polymers, and exhibits the same effects as anion exchange resins.

In other words, when the amount of crosslinking agent used is the same, the functional group density per unit volume increases and the performance of the functional resin increases, and the mechanical strength increases when the amount of crosslinking agent used is the same. It is thought that this will also improve.

Next, examples of the method of the present invention will be described, but the present invention is not limited by these examples unless it departs from the gist thereof.

The chloromethylsterene used in the following Comparative Examples and Examples consists of 65% meta-isomer and 35% para-isomer.

Comparative Example 1 In this comparative example, polymerization was performed in one stage, and the resulting polymer was aminated to produce an anion exchange resin.

106.4 g of water and 6 5.6 grams of calcium chloride in a four-eye flask with a cooling tube. , hollyhinyl alcohol 0.
1. 6 After adding P and purging with nitrogen, 4.6 g of chloromethylstyrene 6 and divinylbenzene 4 with a purity of 57% were added.
18 g and 0.41.2 g of benzoyl peroxide were added, and the mixture was reacted at 80° C. for 8 hours with stirring.

The obtained copolymer was filtered, washed, and dried to give 65.2P.
A copolymer was obtained.

251 of this copolymer was taken, placed in a four-bottle flask equipped with a condenser, and 70 g of benzene and 200 g of a 10% aqueous trimethylamine solution were added thereto, followed by reaction at 50° C. for 4 hours with stirring.

After the reaction was completed, the resin was filtered and further heat-treated in boiling water for 5 hours, and then thoroughly washed with water to give a concentration of 1.12 meq/ml.
3. Exchange capacity of 8 1 meq/g and 58.56%
114 ml of a strongly basic anion exchange resin having a moisture content of 114 ml was obtained.

Example 1 An amount half the amount stated in Comparative Example 1, ie 32.3 g of chloromethylstyrene, 57% purity dipinylbenzene 2.
Polymerization was carried out under the same conditions as in Comparative Example 1 using 0.09 g of benzoyl peroxide and 0.2062 g of benzoyl peroxide.
Equivalent amounts of monomers as in the stage polymerization: 32.3 g of chloromethylstyrene, 2. divinylbenzene of 57% purity.
After adding 0.09 g of benzoyl peroxide and 0.206 y' of benzoyl peroxide and leaving the mixture at room temperature for 16 hours, 103.2 g of water and 688 g of calcium chloride were added, and the mixture was polymerized at 80° C. for 8 hours with stirring.

After thoroughly washing the obtained copolymer, it was dried to obtain 57.
8 g of copolymer was obtained.

25 g of this copolymer was aminated in the same manner as in Comparative Example 1 to obtain 109 ml of a strongly basic anion exchange resin having an exchange capacity of 1.36 meq/ml, 3.85 meq/g, and a water content of 47.2%. .

Example 2 33.5 g of chloromethylstyrene, 0.84 g of fusivinylbenzene with 57% purity and 0.20 g of benzoyl peroxide
The first stage polymerization was carried out in the same manner as in Comparative Example 1 using 6 g of chlorometherstyrene, and 31.1 g of chlormetherstyrene was added to the obtained copolymer.
g, 3.34 g of divinylbenzene with a purity of 57% and 0.206 g of benzoyl peroxide were added, and the second stage polymerization was carried out in the same manner as in Example 1 to obtain 56.6 g (dry product) of the copolymer. Obtained.

15 grams of the thus obtained copolymer was taken and aminated in the same manner as described in Comparative Example 1.1. 30 meq/m
l! 13. Exchange capacity of 5 7 meq/g and 47
．． Strongly basic anion exchange resin 66m with 9% water content
I got l.

Example 3 32.7 g of chloromethylstyrene, 1.67 P of 57% pure divinylbenzene and 0.206 P of benzoyl peroxide
The first stage polymerization was carried out in the same manner as in Comparative Example 1 using
g, 2.51 g of divinylbenzene with a purity of 57% and 0.206 g of benzoyl peroxide were added, and the second stage polymerization was carried out in the same manner as in Example 1 to obtain 58.0 g (dry product) of a copolymer. .

15 g of this copolymer was taken and aminated in the same manner as described in Comparative Example 1. 29 meq/ml, 3.4
69 ml of strongly basic anion exchange resin with an exchange capacity of 6 meq/g and a water content of 4821% was obtained.

Comparative Example 2 58.0 g of chloromethylstyrene in the same manner as Comparative Example 1
, 8.31 g of divinylbenzene with a purity of 57% and 0.686 g of benzoyl peroxide were used to obtain 52.5 g (dry product) of a copolymer.

15 g of this copolymer was taken and aminated in the same manner as in Comparative Example 1. 3 3 meq/ml, 3.42 meq
66.2 ml of strongly basic anion exchange resin containing an exchange capacity of /g and a water content of 43.51% was obtained.

Example 4 29.0 g of chloromethylstyrene, 4.15 g of 57% pure divinylbenzene and 0.343 g of benzoyl peroxide
The first stage polymerization was carried out in the same manner as in Comparative Example 1 using 29.0 g of chloromethylstyrene to the obtained copolymer.
, 415 g of divinylbenzene with a purity of 57% and 0.343 g of benzoyl peroxide were added, and 2 was prepared in the same manner as in Example 1.
Stage polymerization was carried out to obtain 58.3 g (dry product) of a copolymer.

15 g of this copolymer was taken and aminated in the same manner as in Comparative Example 1. 6 2 meq/ml, 3.4
63.2 ml of strongly basic anion exchange resin with an exchange capacity of 3 meq/g and a water content of 39.67% was obtained.

Comparing the ion exchange resin from the product of the example according to the method of the present invention and that from the comparative example using one-stage polymerization, it is found that Examples 1 to 3 have the same proportions of monomer and crosslinking agent as in Comparative Example 1. (In Example 1, it is the same at each stage, and in Examples 2 and 3, it is the same throughout all stages.) However, the water content of the product processed by the method of the present invention is lower than that of the comparative example, The exchange capacity per unit volume is a dog.

Comparative Example 2 and Example 4 also show similar results.

Claims (1)

[Claims] 1. A monomer having a polymerizable unsaturated bond and a halogenated methyl group in the aromatic nucleus is copolymerized with a polyfunctional vinyl monomer, and both of the above monomers are further added to and absorbed into the thus obtained crosslinked copolymer, and the polymerization is repeated. A method for producing a polymer having a halogenated methyl group, characterized in that: