KR930002701B1 - Process for preparing phosphoric xylate resin for adsorbing uranium ion - Google Patents

Abstract

The phosphoric acid based cholate resin of formula (I) or (II) for an absorbing uranium ion is prepared by the steps of: suspension copolymerization of styrene, divinyl benzene and bis-(2-chloroethyl)vinyl phosphonate at 40-100 deg.C for 2-50 hrs.; hydrolysis at 40-130 deg.C for 1-60 hrs. to obtain the copolymer resin; reacting phosphoric trichloride with phenyl gp. or chloroalkyl gp. connected with the phenyl gp. of branched chain in the copolymer at 40-100 deg.C for 2-50 hrs.; hydrolysis and oxydation, at the same time, at 40-130 deg.C for 1-60 hrs.

Description

Method for preparing phosphate chelate resin for uranium ion adsorption

The present invention relates to a method for preparing a phosphate chelate resin useful for adsorption of uranium ions, and more particularly, polymerizes a unit and a styrene unit having a structure that can be converted into a phosphono group on the main chain side, but divinylbenzene is used as a crosslinking agent. After synthesizing the mesh type copolymer resin, the phospho group is added to the phenyl structure of the copolymer resin or the chloroalkyl introduced into the phenyl group, so that the basic skeleton of the copolymer chelate functional group is benzene. The present invention relates to a new process for producing phosphate chelate resin for uranium ion adsorption which enhances the ability of chelate formation to uranium ions by introducing abundant components of these functional groups.

It is known that two phosphono functional groups chelate adsorption for one uranium ion (UO ₂ ⁺⁺ ). [Chem. Reproc. Irradi. Nuclear Fuel. 55, 64 (1977).

Phosphoric acid chelate resins known to date are prepared by esterification of phosphoric acid to polyol resins (polymer chemistry 10, 117 (1953), Ind. Eng. Chem., 46, 1042 (1954)), or styrene copolymers. It was prepared by introducing a phosphono group into the side chain phenyl group (US Pat. Nos. 2,764,562, 2,764,564, Japanese Patent Publication No. 74-18719, German Patents 2,500,744). In the former case, the hydrolysis occurs in the presence of acid or alkali, and the content of phosphate groups decreases, thereby reducing the adsorption effect of uranium ions in the reusability resulting from repeated use of adsorption and desorption. In view of the basic skeleton, since all of the phosphono groups are introduced into the side chain positions of the basic skeleton of the copolymer resin, the arrangement of functional components for chelate formation is simplified, and There was a problem that the ability to form chelates significantly decreased.

Accordingly, there has been a need for the development of new and improved phosphoric acid chelate resins for adsorption of uranium ions.

The phosphate-based chelate resin for uranium ion adsorption that has been recently developed in this background has a side chain when the functional structure of the phosphate group (phosphono group) is centered on the basic skeleton of the copolymer resin to prevent hydrolysis caused by acid or alkali. The phosphono group was introduced directly into the carbon atom at the position, and in order to improve the ability of chelate formation for uranium ions, the phosphono group structure was introduced into the main chain and the side chain position, which is the basic skeleton of the copolymer resin, to chelate function. This was to be improved.

In other words, in order to produce such phosphate chelate resins, phosphono groups were introduced into copolymer resins obtained from styrene and divinyl benzene, and the method introduced phosphono groups into the phenyl group itself, which is a side chain of these copolymer resins, or Methods of introducing phosphono groups after chloromethylation of the phenyl group structure [J. Appl. Polym. Sci., 29, 2045 (1984).

However, all of these methods introduce the phosphono group structure only to the phenyl group, which is the side chain of the copolymer backbone, and the introduction of the phosphono group to the phenyl group reacts due to steric hindrance at the ortho- position of the phenyl group. Is difficult and is mainly introduced only in the para position.

Here, when the phosphono groups introduced on the phenyl group are centered on the basic skeleton of these copolymer resins, the phosphono group, which is a chelate-forming functional group, is less steric-dispersed and has a large chelate-forming ability for uranium ions by being oriented only on one side chain. It showed a tendency to fall.

Therefore, the present invention, unlike the conventional methods as described above, introduces a phosphate group (phosphono group) structure capable of chelation in the main chain, which is a basic skeleton of the copolymer resin, and again a phenyl group or a phenyl group, which is a side chain of the copolymer resin. By introducing a phosphono group for chelate formation into the introduced chloroalkyl group, the uneven structure is formed in a phenyl group which is a side chain or a phosphono group substituted with a chloroalkyl group introduced into the phenyl group in the backbone of the copolymer resin. Adsorption capacity of uranium ions was increased by maintaining the formation capacity larger.

These phosphono functional groups have a structure directly bonded to a carbon atom, so that the reusability is remarkably improved by preventing hydrolysis by acid or alkali solutions used in repeated regeneration of adsorption-desorption. It is an object of the present invention to provide a method for preparing a chelate resin.

Hereinafter, the present invention will be described in detail.

The present invention, in the preparation of uranium ion adsorption chelate resin, of bis- (2-chloroethyl) vinyl phosphonate (hereinafter abbreviated as "CEVP") which is a kind of styrene, divinylbenzene and vinyl phosphonate The copolymer is prepared by suspending the co-polymerization reaction of the unit, followed by hydrolysis, to prepare a copolymer by reacting and hydrolyzing phosphorus trichloride with respect to a phenyl group which is a side chain of the main skeleton of the copolymer or a chloroalkyl group introduced into the phenyl group.

The present invention will be described in more detail as follows.

The present invention is to prepare a phosphate chelate resin for adsorption of uranium ion, a unit having a structure that can be converted into a phosphono group, copolymerizes CEVP, vinyl units of styrene and divinylbenzene, and then hydrolyzes the base of the copolymer resin. A phosphono group structure capable of chelate formation in the backbone was formed, and a phosphorus trichloride was reacted with a phenyl group, which is a side chain of the main skeleton of the copolymer, or a chloroalkyl group introduced into the phenyl group, thereby converting a phosphono group for chelate formation. It was then oxidized at the same time as hydrolysis and converted to phosphono groups.

These chelate copolymer resins have a phosphono group in both the main chain and the side chain of the basic skeleton, and has a chelate-forming ability by forming a concave-convex structure with a phenyl group as a side chain or a phosphono group substituted with a chloroalkyl group introduced into the phenyl group. It is kept larger than this.

In addition, the phosphate chelate resin of the present invention has a structure in which a phosphono functional group is directly bonded to a carbon atom, so that the phosphono group structure is hydrolyzed in the presence of an acid or alkaline solution during regeneration in which the adsorption-desorption process is repeated. Since there is no desorption, it has good chelate formation and durability that can be reused.

In the present invention, a method of preparing a phosphate chelate resin according to the present invention may be represented as follows.

The present invention will be described in more detail. First, toluene is added to a unit such as styrene, divinylbenzene, or CEVP (including alkylvinylphosphonate) as a diluent, and a radical initiator is added to suspend polymerization at 40 to 100 ° C for 2 to 50 hours. After the reaction, the obtained copolymer resin is hydrolyzed at 40 to 130 ° C. for 1 to 60 hours in the presence of an acid catalyst to prepare a resin containing a phosphono group in the main chain of the copolymer resin.

Here, the copolymerization between the hydrophilic CEVP unit and the lipophilic styrene unit is a suspension polymerization method, in which the polymer is formed into a spherical shape, and the inside of the composition includes a large amount of lipophilic styrene structure and the outside of the sphere. Pages are arranged with many hydrophilic CEVP structures.

That is, the CEVP structure used to introduce the functional group for uranium ion adsorption is arranged more on the surface of the chelate resin, so that the CEVP structure higher than the average expected value is introduced on the surface.

According to the present invention, phosphoric trichloride is reacted at 40 to 100 DEG C for 2 to 50 hours in a phenyl group which is a side chain of the copolymer main skeleton or a chloroalkyl group introduced into the phenyl group in these phosphoric acid copolymer resin structures, and 40 to 130 in the presence of an acid catalyst. By oxidizing at the same time with hydrolysis at 1 to 60 hours, the phosphono group structure became more abundant.

It is possible to produce a phosphate chelate resin that exhibits a good chelating ability by arranging the phosphono groups introduced into the phenyl group, which is the side chain of these copolymers, at the apex and the uneven state of the main chain.

On the other hand, CEVP, a kind of vinyl phosphonate used in the present invention, is preferably used within 0.45 mol% (maximum value in solution polymerization) of the total composition of the copolymer, and if the content of CEVP is 0.45 mol% or more, It is not preferable because the copolymer yield decreases and the reaction time is very long due to the steric hindrance of the copolymer CEVP structure, the possibility of homopolymerization of CEVP, and the chain transfer reaction to CEVP itself.

In addition, in the present invention, the amount of divinylbenzene used as a crosslinking agent in the copolymerization may be used in a ratio of 2.0 to 30% by weight based on the total amount of the used monomers.

In other words, the divinylbenzene is a crosslinking agent that gives mechanical strength to the styrene-based spheroidal copolymer and acts as a ladder of the network structure through which uranium can enter, and when the amount is less than the amount used, the network structure does not act as a ladder. It is not good, and if it is large, the surface area becomes small due to the increase of the degree of crosslinking and the adsorption effect is reduced, which is not good.

In addition, a small amount of organic diluent such as toluene, cyclohexane, etc. which can be used during copolymerization in the present invention is used at a ratio of 2.0 to 20% by weight based on the total amount of the monomers used, and they are spherical air as a precipitant during the copolymerization reaction. It is used to make physical concavo-convex structure of the copolymer, and after the reaction, it is physically mixed in the spherical copolymer, and the specific surface area of the spherical copolymer is increased by drying them.

Meanwhile, in the present invention, a radical polymerization method is used, wherein as the radical initiator, benzoyl peroxide, P, P'-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, di-t-butyl peroxide, and Both peroxide initiators, such as potassium lactate or ammonium persulfate, and azo radical initiators, such as bis azoisobutylonitrile, can be used.

In addition, the copolymerization method of the present invention uses a radical suspension polymerization method, wherein the suspending agent is methyl cellulose, partially hydrolyzed polyvinyl alcohol, polyvinylpyrrolidone or a mixture thereof. The amount of the suspending agent used herein is 0.01 to 4.0% by weight, particularly 0.1 to 2.0% by weight based on the total amount of used monomers.

In general, such suspension polymerization is carried out in an aqueous dispersion (aqueous dispersion), so even in the copolymerization method of the present invention, radical polymerization takes place in the water dispersion phase, wherein the weight ratio of water to organic units is preferably 0.5 to 15 weight ratio.

If less than 0.5 weight ratio of water is added, the viscosity becomes so large that it is difficult to obtain a uniform aqueous phase. On the other hand, if more than 15 weight ratio is added, productivity decreases and a large amount of water needs to be heated. Will not.

According to the present invention, the size of the spherical copolymer particles is adjusted from the amount of the suspending agent used herein and the weight ratio between the water and the organic units in the aqueous phase.

The hydrolysis of the phosphoric acid copolymer obtained in the present invention is added to the ethanol of 2 to 10 times by weight and the concentrated hydrochloric acid of 1 to 20 times by weight per dry copolymer resin and maintained at 40 to 130 ℃ for 1 to 60 hours Subsequent purification can be accomplished by blowing off the volatile components, washing the residue with water and methanol and then drying.

On the other hand, the additional phosphono group introduction method for the phenyl group which is the side chain of the phosphate copolymer resin obtained in the present invention or the chloroalkyl group introduced into the phenyl group is 0.01 to 20 to 20 times by weight of the cyclohexane solution per dry copolymer resin weight. Using a 10-fold weight ratio of aluminum chloride as a catalyst, 0.01 to 15-fold weight ratio of phosphorus trichloride is reacted for 2 to 50 hours at Friedel-Crafts at 40 to 100 ° C.

In order to introduce a chloroalkyl group to the phenyl group, which is a side chain of the copolymer resin basic skeleton, 0.01 to 10 times by weight of aluminum chloride in a 1 to 30 times weight ratio of cyclohexane solution per weight of the copolymer is used as a catalyst. The chloroalkyl alkyl ether in the weight ratio is reacted.

Next, the reaction product was separated by filtration, washed with distilled water and methanol, and a nitric acid solution having a concentration of 1 to 30% by weight was added at a weight of 2 to 30% by weight of the reactant resin to activate the phosphino structure. The stock is added at a weight ratio of 50 times and oxidized simultaneously with hydrolysis at 40 to 130 ° C. for 1 to 60 hours. The final product thus obtained may be washed with water and methanol after filtration and dried.

In connection with the present invention as described above, the functional structure of tributyl phosphate is widely used for adsorption recovery of uranium ions.

Therefore, in the production of the phosphate chelate resin of the present invention, the phosphono structure, which is considered to be the same as the function of tributyl phosphate for uranium ion, in the design of the coordination band for the functional portion of the chelate (O = P structure) The effect of phosphono group content, the effect of the positional change of the main and side chains of the phosphono group in the chelate copolymer backbone, the effect of crosslinking agent content and specific surface area size, and the reusability from adsorption-desorption, etc. In consideration of the above, it is possible to produce a phosphate chelate resin with remarkably improved adsorption and reusability to uranium ions compared to conventional products.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not limited by the Examples.

EXAMPLES 1-10

치)를 2.5로 하고, 1% 메틸셀룰로오즈 수용액을 분산제로 사용하였다.Styrene, divinylbenzene, bis- (2-chloroethyl) vinylphosphonate (CEVP), toluene, and the like were added to a reactor with a stirrer, and 0.2 wt% of benzoyl peroxide was used as a polymerization initiator. Defense with the monomers (

N) to 2.5, and a 1% aqueous solution of methyl cellulose was used as a dispersant.

The suspension polymerization was maintained at 70 ° C. for 25 hours, and the resulting polymerization product was filtered and washed with water. The resultant was dried for 48 hours in a vacuum dryer maintained at 60 ° C., and then filtered through a 60/80 mesh sieve.

The introduction of the phosphono group into the main chain of the copolymer resin was carried out by hydrolysis by refluxing at 90 ° C. for 42 hours, adding 4 parts by weight of methanol and triple hydrochloric acid per weight of the dried resin obtained by the copolymerization reaction. Its purification gave off volatiles, washed the residue with distilled water and dried.

Then, in order to introduce a phosphono group to the phenyl group, which is a side chain of the copolymer resin skeleton, an 8 weight ratio cyclohexane solution per weight of the chelating resin in which the phosphono group is introduced into the main chain was used, and 0.25 weight ratio was present in the presence of 0.25 weight ratio aluminum chloride catalyst. Phosphorus trichloride was reacted at 70 ° C. for 30 hours, and the reaction mixture was filtered and washed with water and methanol and dried.

Here, the dried reactant was oxidized at the concentration of 2% nitric acid solution per weight at the same time with hydrolysis at 80 ° C. for 20 hours. This was then vacuum dried at 60 ° C. for 48 hours to produce a yellow spherical chelate resin. The composition, phosphorus content and uranium ion adsorption amount of the obtained human phosphorus chelate resin were as shown in Table 1 below.

TABLE 1

a In the above table, the adsorption amount of uranium ion is calculated as the concentration difference of the solution after adding 0.2 g of sample to 20 ml of uranium ion solution of pH = 4.27, 21.2 ppm concentration and stirring for 28 hours.

b All amounts used for copolymerization are considered to be reacted.

c Calculated by chlorine analysis.

d The composition of the product obtained in each reaction for the main and side chains is calculated from the weight change before and after the reaction.

e weight percent

Comparative Examples 1 to 5

치)를 2.5로 하고 1% 메틸셀룰로오즈 수용액을 분산제로 사용하였다.Styrene, divinylbenzene, and the like were added to the reactor with a stirrer, and as the polymerization initiator, benzoyl peroxide was used in an amount of 0.2% by weight based on the monomers.

C) to 2.5 and a 1% aqueous solution of methyl cellulose was used as a dispersant.

The suspension polymerization reaction was maintained at 70 ° C. for 25 hours, and the resulting polymerized product was washed with water. The resultant was dried for 48 hours in a vacuum dryer maintained at 60 ° C. and filtered through a 50/80 mesh sieve.

Then, in order to introduce a phosphono group to the phenyl group, which is the side chain of the copolymer resin skeleton, a 0.25 weight ratio of phosphorus trichloride was added in an 8 weight ratio cyclohexane solution per weight of the copolymer resin in the presence of 0.25 weight ratio of aluminum chloride catalyst at 70 ° C for 30 hours. The reaction was filtered, washed with water and methanol and dried. Here, the dried reactant was oxidized at the concentration of 2% nitric acid solution per unit weight at the same time by hydrolysis at 70 ° C. for 20 hours.

This was then vacuum dried at 60 ° C. for 48 hours to produce a yellow spherical chelate resin. The composition, phosphorus content and uranium ion adsorption amount of the obtained chelate resin were as shown in Table 2.

Comparative Examples 6 to 10

치)를 2.5로 하고, 1% 메틸셀룰로오즈 수용액을 분산제로 사용하였다.Styrene and divinylbenzene were added to the reactor with a stirrer, and as the polymerization initiator, benzoyl peroxide was used in an amount of 0.2% by weight based on the monomers.

N) to 2.5, and a 1% aqueous solution of methyl cellulose was used as a dispersant.

The suspension polymerization was maintained at 70 ° C. for 25 hours, and the resulting polymerization product was filtered and washed with water. The resultant was dried for 48 hours in a vacuum dryer maintained at 60 ° C., and then sieved with a 50/80 mesh sieve.

Then, in order to introduce chloromethyl group to the phenyl group, which is the side chain of the copolymer resin backbone, at 80 ° C with 1 part by weight of chloromethyl methyl ether in the presence of 0.3 part by weight of aluminum chloride catalyst in 10 parts by weight of cyclohexane solution After reacting for 20 hours, the mixture was filtered and dried for 48 hours in a vacuum dryer maintained at 50 ℃.

Then, in order to introduce a phosphono group to the chlorobenzyl group, which is the side chain of the basic skeleton of the copolymer resin, a 0.25 weight ratio of phosphorus trichloride was added at 80 ° C in a presence of 0.25 weight ratio of aluminum chloride catalyst in an 8 weight ratio cyclohexane solution per copolymer resin weight. The reaction was carried out for a period of time and the reaction was filtered, washed with water and methanol and dried. Here, the dried reactant was oxidized simultaneously with hydrolysis for 20 hours using 10% by weight of a nitric acid solution at a concentration of 2% per weight. This was then dried at 60 ° C. for 48 hours to give a yellow spherical chelate resin. The composition, phosphorus content and uranium ion adsorption amount of the obtained phosphate chelate resin were as described in Table 2 below.

TABLE 2

a In the above table, the adsorption amount of uranium ion is calculated as the concentration difference of the solution after adding 0.2 g of sample to 20 ml of uranium ion solution of pH = 4.27, 21.2 ppm concentration and stirring for 28 hours.

b All the amount used for copolymerization is considered to react.

c Calculated by chlorine analysis.

d The composition of the product obtained in each reaction for the main and side chains is calculated from the weight change before and after the reaction.

e weight percent

Claims (5)

In preparing phosphate chelate resin for uranium ion adsorption, styrene, divinylbenzene, and bis- (2-chloroethyl) vinylphosphonate, a unit capable of converting a product into a vinyl phosphate structure, were added at 40 to 100 ° C. After the suspension copolymerization for ˜50 hours, hydrolysis at 40 to 130 ° C. for 1 to 60 hours, phosphorus trichloride was reacted at 40 to 100 ° C. for 2 to 50 hours at a phenyl group which is a side chain of the obtained copolymer resin or a chloroalkyl group introduced to the phenyl group. A method for producing a phosphate chelate resin for uranium ion adsorption, characterized in that it is produced by oxidizing at the same time for 1 to 60 hours at 40 to 130 ° C. The method of claim 1, wherein the bis- (2-chloroethyl) vinyl phosphonate is used within 0.45 mol% of the total composition of the copolymer, and divinylbenzene is used at 2.0-30% by weight based on the vinyl units used. Method for producing a phosphate chelate resin, characterized in that. The method of claim 1, wherein the phosphorus trichloride is dissolved in a solvent of 2 to 20 times the weight ratio of cyclohexane in the presence of 0.01 to 10 weight ratio of aluminum chloride catalyst per unit weight of the copolymer to use a 0.01 to 15 times weight ratio Process for producing phosphate chelate resin. The method of claim 1, wherein the introduction of the chloroalkyl group to the phenyl group of the copolymer resin is 0.05 to 15 times by using 0.01 to 10 times the weight ratio of aluminum chloride in the cyclohexane solution of 1 to 30 times the weight ratio of the copolymer resin. A method for producing a phosphate chelate resin, characterized by using chloroalkyl ether in a weight ratio. The phosphate system according to claim 1, wherein the hydrolysis and oxidation reaction is performed by using a nitric acid solution having a concentration of 1 to 30% by weight based on the weight of the dry copolymer resin after washing and drying after the Friedel-Craft reaction. Process for preparing chelate resin.