JPH0414126B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the resin obtained by the reaction of chloromethylated cross-linked polystyrene and polymeric amines,
The present invention relates to a method for producing a chelate resin obtained by alkylene phosphonation.

Such resins are particularly useful for selectively removing metal ions from aqueous solutions.

Many chelate resins that can selectively remove metal ions from aqueous solutions have been devised, but most of them have aminocarboxylic acid groups. Patent No.
No. 7425610 describes -CH ₂ NHRPO(OH) ₂ (where R is C ₁
~ _C3 alkylene groups)). After forming a primary amine on an aromatic nucleus, the aminoalkylene-phosphonate (-CH ₂ NHRPO(OH) ₂ ) group is converted into one aromatic nucleus by reacting with an appropriate phosphonating agent, aldehyde, etc. The number of functional groups is proportional to the aromatic nucleus of the copolymer, and at the same time it depends on the primary amine group induced into the aromatic nucleus, which increases the metal adsorption ability. There is a limit to
In addition, the resin obtained here is brittle and has the disadvantage of being easily crushed during use and recycling.

In order to improve these problems, we conducted studies and found that polyethyleneimine or a condensate of meta-xylene diamine and epichlorohydrin was used as the raw material for introducing amino groups, and a plurality of groups were added to one aromatic ring of styrene. By introducing a monoamine group and a secondary amine group and further introducing an alkylene phosphonate group thereto, it is possible to improve the adsorption ability of metal ions and to obtain a chelate resin that is elastic and resistant to crushing. I found out.

The polyethyleneimine used here has a molecular weight of
300 or more ethyleneimine polymer, with an alkyl group having 1 to 5 carbon atoms as a substituent bonded to N,
Alternatively, those containing polyethyleneimine partially substituted with a phenyl group or the like are also effective for the purpose of the present invention.

An object of the present invention is to provide a method for producing a chelate resin that can efficiently and selectively remove metal ions from an aqueous solution.

The resin according to the invention consists of a cross-linked polystyrene copolymer having a large number of >NRPO(OH) ₂ per aromatic nucleus.

Such resins can be efficiently produced by using polymeric amines, such as chloromethylated styrene-divinylbenzene (DVB).
The copolymer is aminated with polymeric amines, and then the phosphonating agent and aldehydes are reacted to produce -
A resin having _two NRPO(OH) groups is obtained.

The resin according to the present invention can efficiently and selectively remove metal ions in water, has better chemical and mechanical stability than conventional resins, and has extremely high adsorption rate and adsorption capacity for metals. It's big.

The chloromethylated crosslinked polystyrene of the present invention can be obtained by chloromethylating a crosslinked copolymer such as styrene-divinylbenzene using chloromethyl ether, or can be obtained by chloromethylating a crosslinked copolymer such as styrene-divinylbenzene, or by chloromethylating a crosslinked copolymer such as styrene-divinylbenzene, or a combination of styrene, vinylbenzyl chloride, and divinylbenzene. Although it can be obtained by performing a copolymerization reaction using a crosslinking monomer, it is preferable to use a styrene-divinylbenzene copolymer. As the crosslinking agent, in addition to divinylbenzene, for example, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trivinylbenzene, etc. can be used.

Taking styrene-divinylbenzene copolymer as an example, these granular solid resins are generally obtained in spherical form, contain 1 to 25% crosslinking agent, and are either gel type or porous. It is of type.

There are two methods for introducing chloromethyl groups into aromatic rings: one is to react the polymer with chloromethyl ether, and the other is to directly introduce a monomer such as vinylbenzyl chloride that has a chloromethyl group in the molecule during the polymerization reaction. Generally speaking, there is a method of introducing a chloromethyl group into a copolymer, and the present invention can be used with either method.

Once the chloromethylated styrene-divinylbenzene copolymer is obtained, the chloromethyl group is then reacted with polymeric amines to obtain an aminated resin, but this reaction generally involves removing the resin using an organic solvent. There is a method of swelling it and reacting it with an amine compound. However, it is desirable to use a water-soluble organic solvent to react with polymeric amines.

i.e. dioxane, acetone, methylal,
The copolymer is swollen with a swelling agent such as tetrahydrofuran, dimethylformamide and N-methylpyrrolidone. Further, these organic solvents are not limited to the above compounds. By further adding a polymeric amine and further adding water, the viscosity of the system can be lowered and the reaction can proceed smoothly. Although the reaction temperature is not particularly limited, it is preferable to carry out the reaction at the reflux temperature of the solvent so that the amination can proceed efficiently.

Next, to alkylene-phosphonate the aminated resin, a reaction is carried out using phosphorous acid or phosphorous trihalide as a phosphonating agent in the presence of hydrochloric acid and water together with aldehydes, trioxane, paraformaldehyde, etc. By doing so, you can get what you want. Examples of the aldehydes used here include formaldehyde, acetaldehyde, ethylaldehyde, propionaldehyde, and the like. The reaction temperature is preferably refluxed with water.

Introducing a metal ion into the cation exchange group of the alkylene-phosphonated resin is carried out by a commonly used method.

For example, in order to obtain a sodium salt type, the resin is washed with a caustic soda aqueous solution in a batch or column type, and the excess alkali is washed out with water.

The use of the chelating resins of the present invention in the removal of metal ions from aqueous solutions is not limited as to operating conditions such as pH, temperature, concentration, etc., nor is there any limitation as to the ionic type of the resin.

Next, the present invention will be explained by examples.

Comparative Example 1 Using a commercially available aminomethyl phosphate type resin, an aqueous copper ion solution adjusted to 50 ppm in advance was used to measure the adsorption amount of copper, which was found to be 20 mg/g of resin. Furthermore, the crushing strength of one particle of the resin used here was measured. A grain of resin was taken and weighed, and the number of grams of weight when crushed was measured. As a result, the amount was 150g/piece.

Example 1 Put 4.5% of a 0.6% polyvinyl alcohol aqueous solution into a three-necked flask equipped with a stirrer and a reflux condenser, and add divinylbenzene (divinylbenzene content: 55%) to 500g of vinylbenzyl chloride while stirring.
A solution containing 42 g of 42 g of isooctane, 490 ml of isooctane, and 4 g of benzoyl peroxide was added thereto, and the temperature was raised to 90° C. over 1 hour, and a suspension polymerization reaction was carried out at the same temperature for 8 hours. After the reaction was completed, the resin was filtered, washed with water, and dried to obtain a bolus type chloromethylated polystyrene-6% divinylbenzene resin. 300ml of the resulting resin
was swollen in 360 ml of acetone, 93 g of polyethyleneimine with a molecular weight of 300 and 250 ml of water were charged thereto, and the reaction was carried out under reflux for 5 hours. The obtained resin was filtered and further washed thoroughly with pure water. 136 ml of 35% hydrochloric acid was added to the resulting resin, the mixture was stirred at 90°C for 2 hours, and then 95 g of phosphorous acid was added.
Add 35g of paraformaldehyde and 300ml of water,
The reaction was carried out under reflux for 2 hours. The resin was filtered off, thoroughly washed with water, and then treated with a 10% NaOH aqueous solution to obtain a Na-type resin. The adsorption amount of this resin was measured using the same copper ion aqueous solution as in Comparative Example 1, and the adsorption amount was 25 mg/g-resin.

Moreover, the crushing strength of the particles of this resin was 175 g/piece.

Example 2 The same raw materials and amounts as in Example 1 were used, and the same conditions were used as in Example 1, except that 93 g of polyethyleneimine with a molecular weight of 30,000 was used instead of the polyethyleneimine of Example 1, and 360 ml of dioxane was used instead of acetone. The reaction was carried out to obtain a Na-type resin.

For this resin, the adsorption amount was measured using the same copper ion aqueous solution used in Comparative Example 1. The amount of adsorption is
It was 27 mg/g of resin. The crushing strength of the resin particles was 180 g/piece.

Example 3 Chloromethyl ether was added to 200 g of a granular copolymer resin consisting of 98% styrene and 2% divinylbenzene.
800 ml and 60 ml of stannic chloride were added, and a chloromethylation reaction was carried out for 10 hours at the reflux temperature of chloromethyl ether. After the reaction, the resin was filtered, washed with a 5% methanol solution of hydrochloric acid, then with acetone, and dried to obtain 2% chloromethylated polystyrene.
Divinylbenzene resin (chlorine content 21.6%) was obtained. To 120 g of the obtained resin, 160 ml of tetrahydrofuran was added as a swelling agent, and an epichlorohydrin condensate of meta-xylene diamine (gascamine) was added.
103 g of G328 (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in 250 ml of water, added, heated, and reacted under reflux for 2 hours. After the reaction, the resin was separated and thoroughly washed with water. To the aminated resin obtained, 130 g of a 37% formalin aqueous solution and 200 ml of water were added, and phosphorus trichloride was added under stirring.
220g was added dropwise over 1 hour. The reaction was further carried out under reflux for 2 hours, and the resin was separated and thoroughly washed with water. Further, the same treatment as in Example 1 was carried out.
A Na-type resin was obtained.

As a result of measuring the adsorption amount of this resin using the same copper ion aqueous solution as in Comparative Example 1, the adsorption amount was
It was 27.5 mg/g-resin. The crushing strength of the resin particles was 165 g/piece.

Claims (1)

[Claims] 1 Phosphous acid or trihalogen is added to a resin resin that has been aminated by reacting chloromethylated cross-linked polystyrene with (a) a condensation reaction product of meta-xylene diamine and epichlorohydrin or (b) polyethyleneimine with a molecular weight of 300 or more. 1. A method for producing a chelate resin, comprising alkylene phosphonation using phosphorus chloride and at least one selected from the group consisting of formaldehyde, acetaldehyde, trioxane, and paraformaldehyde.