JPS58153541A - Ion exchange resin - Google Patents

Abstract

PURPOSE:To provide an ion exchange resin which consists practically of linear polyimide and is so formulated as to be used stably at high temp. by incorporating a specific imide unit and a sulfonated imide unit as repetitive units and specifying the rate of imidation. CONSTITUTION:This invetion relates to an ion exchange resin which has the imide unit A expressed by a general formulaI(R<1> is a bivalent org. group) and the sulfonated imide unit B expressed by the general formula II R<2> is an aromatic group of (m+2) valency, -SO3M is -SO3H or its metallic salt, m is 1-4 as repetitive units and consists substantially of linear polyimide. In this structure, the sulfonated imide unit B is so regulated as to occupy 5-90mol% of the entire amt. of the units and the rate of imidation the number of imide rings/(the number of imide rings + the number of amic acid structure) as to attain >=70%. Since this ion exchange resin is resistant to heat, and has stability against high temp., the resin is usable for separating and recovering heavy metal ions in water, separating and recovering radioactive nuclear species in reactor water, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion exchange resin, and more particularly to an ion exchange resin that can be stably used even at high temperatures.

Various ion exchange resins are already known, and are used in various fields such as the separation and recovery of heavy metal ions in wastewater, the separation and recovery of radionuclides in the reactor water of power reactors, as well as reaction catalysts. However, its use is subject to many restrictions due to its poor heat resistance.For example, a general-purpose strongly acidic cation exchange resin with a sulfonic acid group as an exchange group has a working temperature of 120℃ in gel form and 120℃ in dish form. The limit is 150°C, and as long as the ion exchange resin is made of a styrene-divinylbenzene copolymer, the resin will partially soften or decompose if exposed to high temperatures of 200°C or higher. For this reason, it has also been proposed that a heat-resistant ion exchange resin is obtained by producing polyphenylene ether having a halomethyl group as a substituent, and converting this halomethyl group into an acidic group such as a sulfonic acid group or a sulfonic acid group. Do you know (Tokuko 1977-)
No. 24398), the reaction process is complicated, and the resin cannot be obtained quantitatively, so there is a big disadvantage in manufacturing.

The present invention was made to solve the various problems described above, and an object of the present invention is to provide an ion exchange resin that has excellent heat resistance and can be used stably even at high temperatures.

The ion exchange resin according to the present invention has an imide unit (2) represented by the general formula (wherein R1 represents a divalent organic group).
(may contain an amic acid structural unit which is a precursor structure of the unit (4)) and the general formula (where R' is (m+23 valent aromatic group, -80sMj
1-80sB or a metal salt thereof, m is an integer of 1-4. ) represented by sulfonated imide units (to) (units (
may contain an amic acid structural unit which is a precursor structure of (to)) as a repeating unit, occupying 5 to 90 moles of the total amount of units (to), and [number of imide rings/
It is characterized by being made of a substantially linear polyimide having an imidization rate defined by (the number i of tens of asymmetric imide ring structures) or higher than TOS.

In the polyimide forming the ion exchange resin of the present invention, the units (to) are 5 to 5 of the total amount of units (2) and (g).
The amount is 90 moles, preferably 20 to 70 moles. If the unit (g) is less than 5 mol% of the total amount of units, the ion exchange capacity of the polyimide is too small to be practical (on the other hand, polyimide exceeding 900 mol% generally has a large molecular weight). This is because the strength is poor and the polyimide swells when adsorbing metal ions, resulting in a decrease in strength.

Moreover, the polyimide used in the present invention is usually 0.
40-1.00. Preferably 0.60 NO, 85) intrinsic viscosity (as a N-methyl-2-pyrrolidone solution at 30°C
The same applies hereafter. , ).

If the intrinsic viscosity is too low, the polyimide will not have practical strength, while if the intrinsic viscosity is too high, difficulties may arise in the process of molding the polyimide into various shapes. The average molecular weight of the polyimide used in the present invention, which may be related to this intrinsic viscosity, is usually
10,000 N120,000, preferably 20,000~
It is 5oooo.

As described later, the polyimide containing the unit (2) and the unit [presence] as repeating units preferably has a polyimide of 1°2,
Polyimide can be obtained by condensing 3.4-butanetetracarboxylic acid (hereinafter referred to as BTO) and diamine in an organic solvent, or depending on the reaction conditions, the type of diamine used, etc. 2) and [Yes]
In addition to these, they contain repeating units of an amic acid structure, which is their precursor structure. As a repeating unit having this amic acid structure, for example, 0 0
(80 Hata Mum000H
It will be easily understood that O and the like can be mentioned.

In the present invention, the polyimide is allowed to have a certain amount of such amic acid structural units.

That is, it is possible to use a polyimide whose imidization rate defined by the following is about 70 or more of the total units. Imidization rate is about 70
If it is less than -%, the resulting polyimide will have poor heat resistance, which is undesirable. Therefore, the imidization rate in the polyimide used in the present invention is about 70% or more, preferably 90% or more, and particularly preferably about 98% or more. Particularly preferred is a polyimide that does not substantially contain an amic acid structure.

In addition, even when the polyimide has a polyamic acid structure like this, the polyimide contains the polyamic acid structural unit which is the unit and its precursor structure in an amount of 5 to 90 moles, preferably 20 to 70 moles of the total amount of units. It's good to attack 0.

Next, in the unit (2) of polyimide, R1 is 2
A valent organic group, specifically an aromatic, aliphatic or alicyclic divalent organic group, or a divalent organic group in which these groups are bonded via an organic bonding group X.

Here, as a specific example of the bonding group X, a carbon-carbon bond directly bonding a divalent organic group, -0Hs-1-0-OH5-1
-0(〇〇-1-8αm-5-O-1-NH-1-8-
1-0ONH-1 (wherein ♂ and R4 each independently represent a cycloalkyl group or phenyl group having 3 to 10 carbon atoms), and the like.

Preferably, R1 is an aromatic group, eg (However, X is the same as above.) I can list many things.

In addition, R1 in the unit @ is an (m+2)-valent aromatic group, preferably of the general formula (wherein -sosM, X and m are the same as above,
p and q are numerical values of 0 to 4, and p+q=m. It is represented by J, and OsM and the like can be cited as preferred specific examples.

In both Bl and V, the aromatic ring may have an alkyl group such as a methyl group or an ethyl group.

The polyimide used in the present invention is, for example, JP-A-56-55
It can be obtained according to the method for producing carboxylated polyimide described in Publication No. 428, and preferably tL< is represented by BTO and the general formula % (where R1 is the same as above). diamine and the general formula (however, R1, -80°C and m are the same as above)
The aromatic diamino represented by the following formula can be obtained by reacting in an organic solvent, usually under heating, under conditions where the molar ratio of the total amount of these diamines to the total amount of diamines is about 1. It is preferable that the diamine represented by the formula (1) is used in the form of a sulfonate such as a sodium salt or a potassium salt. The ion exchange resin of the present invention can be obtained by regenerating the obtained acid groups.

As the organic solvent, it is preferable to use one that dissolves BTO and diamine as well as dissolves the resulting polymer, and usually includes N-methyl-2-pyrrolidone, dimethylformamide, N,N-dimethylacetamide, and N-methyl. -2-Piperidone, dihydroxybenzene, phenols such as phenol and cresol are used. Particularly preferred solvents are N-methyl-2-pyrrolidone and N-methyl-2-piperidone. These have high solubility in the raw materials and the resulting polymer, and have a high boiling point, so one reaction must proceed rapidly at high temperatures.

This is because it can be done.

General - The amount of solvent used is not particularly limited, and it is sufficient to use a sufficient amount to allow the reaction to proceed uniformly. Usually, 60 to 90,011 parts per 11,100 parts by weight of B'I'0 and diamine in total. It is a quantity part.

The reaction is usually carried out at 100 to 300'C mJf.
Do time. Under these conditions, the resulting polyimide is a linear polymer consisting essentially of repeating units (2) and (2). The amic acid structure is formed together with the ring.

In the diamine represented by (1) above, 11 is as described above, and specific examples of such diamine include m-
7 Enylene diamine, p-phenylene diamine, 4.4
'-Diaminodiphenylmethane, 4゜4'-Diaminodiphenyl ether, 3.4'-Diaminodiphenyl ether, 4.4'-Diaminodiphenyl sulfide,
4.4'-diaminodiphenylsulfone, p-bis(4
-aminophenoxy)benzene, m-bis(4-aminophenoxydinebenzene, N.

N-piperazine-bis(p-aminobenzimide), m
-xylylenediamine, p-xylylenediamine, bis(4-aminocyclohexylunemethane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, 1,4-diaminocyclohexane, bis(4-
Examples include adenophenyl J diethylsilane.

In addition, specific examples of aromatic diamines represented by the above (phantom) include 3.5-cyanobenzenesulfonic acid, 3.3-cyanobenzenesulfonic acid,
'-Dimethylbenzidine-2,2'-disulfonic acid, 4
．． 4'-diaminodiphenylmethane-3,3'-disulfonic acid, 4,4'-diaminodiphenyl ether-3J
'-disulfonic acid, benzidine-2,2I-disulfonic acid, 4,4'-diaminostilbene-2,2'-disulfonic acid, diaminonaphthalenedisulfonic acid, and the like.

The ion-exchanged tung fat according to the present invention can be used in various forms such as powder, beads, film, membrane, tube, thread, etc., but is not limited in shape.

As described above, the polyimide resin used in the present invention is obtained by melting using a retrieval solvent as a solvent, so it can be easily molded into various shapes.

For example, to obtain a fat powder of polyimide, a solvent that is compatible with the reaction solvent and does not dissolve the polyimide (hereinafter referred to as a coagulating solvent), preferably water, alcohol, or a mixed solvent thereof, is vigorously stirred, The polyimide solution may be gradually added to this. In addition to the above-mentioned coagulating solvent, a mixed solvent of water and an organic solvent having compatibility with water, such as acetone, ethylene glycol, diethylene glycol, ethylene glycol monomethyl ether, etc., can be used as the coagulating solvent. The content of these organic solvents in the mixed solvent is usually less than 101 it%, or if desired, these organic solvents can be used alone as coagulation solvents.

In order to obtain bead-shaped resin, for example, a polyimide solution may be added in the form of droplets to the coagulation solvent to coagulate the polyimide. In addition, K, which forms polyimide oil into a film,
This can be done by applying a polyimide solution onto a suitable substrate, such as a glass plate or a metal plate, and heating it to volatilize the solvent.Furthermore, after applying the polyimide solution onto the substrate, it can be immersed in the above-mentioned coagulating solvent. , a polyimide film can be obtained. Note that a porous polyimide membrane can be obtained by dissolving a swelling agent made of a metal salt soluble in a coagulating solvent in a polyimide solution and then immersing the solution in a coagulating solvent. A method for manufacturing such a polyimide porous membrane is already known, for example, as described in the above-mentioned Japanese Patent Application Laid-Open No. 56-55428. Halides of metals, preferably lithium, sodium, potassium and magnesium, in particular, but not limited to, chlorides and bromides, nitrates, sulfates and mixtures thereof are used. Preferably, lithium nitrate, potassium nitrate, lithium chloride, potassium chloride, calcium chloride, calcium nitrate, calcium sulfate, potassium bromide, etc. are used. Such swelling agents are typically used in an amount of 10 parts per 100 parts of polyimide.
01i theory section and below are preferred.

is used in an amount of 10 to 30 parts by weight. This is because if the amount of swelling agent used is too large, it tends to impede the uniformity of the polyimide solution, making it difficult to obtain a uniform film. Incidentally, instead of adding these inorganic swelling agents to the polyimide solution during the polymerization reaction, the inorganic swelling agent can be added in advance during the polymerization reaction, and the polymer solution thus obtained can be used for film formation.

Moreover, polyhydric alcohols and their ether derivatives can also be used as swelling agents. Specific examples include ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol monomethyl ether, etc.
Ethylene glycol and its lower alkyl ether, glycerin, 1,3-furopanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2,3,4-butanetetraol, Polyhydric alcohols such as pentaerythritol, xylift, and sorbitol can be mentioned.

Furthermore, in addition to the above, organic swelling agents that are compatible with water may be used. Examples of these include acetone, tetrahydrofuran, formic acid, acetic acid, and the like.

These organic I#IIIMs are typically polyimide 10
0 to 5 to 300 parts by weight per part, preferably 10 to 1
00 parts by weight are used.

If desired, it may be used in combination with the inorganic expansion described above.

When obtaining a polyimide porous membrane as described above, woven or nonwoven fabric sheets or tubes made of polyester fibers, charcoal fibers, or other inorganic fibers can also be used as the base material.

By applying a polyimide solution onto such a support substrate and forming a membrane, a porous membrane integrated with these substrates can be obtained.

The polyimide is coagulated into an acid form by immersing it in a coagulating solvent.

The temperature at which the coagulation is performed is generally below the boiling point of the coagulating solvent. In the case of a coagulating solvent or water, the temperature is usually 0 to 80°C, preferably 0 to 50°C. The coagulation time is not particularly limited, and 1 to 10 hours is usually sufficient.

Since the ion exchange resin of the present invention can be obtained in various shapes as described above, it can be used for ion exchange in various ways depending on the shape. For example, the resin may be packed in a column or tower and passed through a solution containing the metal ions to be ion-exchanged, or the resin may be immersed in the solution.

The ion exchange resin of the present invention has excellent hydrophilicity due to the polyimide skeleton and the sulfonic acid groups it has, and also has solvent insolubility, heat resistance, and strength due to the polyimide skeleton, so it can be used in a temperature range of up to 350°C. It can withstand ion exchange and can be practically used for ion exchange over a warm friction range of 80 to 300°C. In particular, it is a great advantage that ion exchange can be performed in a high temperature range of 200° C. or higher, which is difficult to use with conventional ion exchange resins made of styrene-divinylbenzene copolymers. Generally, the rate of ion exchange increases as the processing temperature increases, so the ion exchange resin of the present invention can shorten the processing time. Furthermore, in the case of a solution containing metal ions, such as nuclear reactor water, which is discharged at high temperature, the solution can be cooled and ion exchanged in places. Of course, ion exchange can also be performed at room temperature. The time for contacting the metal ion-containing solution with the ion exchange resin of the present invention is as described above.
Depending on the temperature of the processing solution, usually 1 minute to 30 hours.
Preferably, the time is about 5 minutes to 2 hours, but the time is not limited thereto.

In order to recover the metal ions captured by the ion exchange resin of the present invention, for example, the ion exchange resin can be brought into contact with an aqueous mineral acid solution, in the same way as conventional ion exchange resins that use sulfonic acid groups as ion exchange groups ( , whereby the ion exchange resin is simultaneously regenerated and can be reused.

The present invention will be specifically explained below with reference to polyimide production examples and examples, but the present invention is not limited to these examples in any way.

Production Example 1 BT823.4 f (0.1 mol), 3 was placed in a reaction vessel equipped with a stirrer, a nitrogen gas inlet, a reflux tower with a reaction product water removal device, and a jacket bath that can be heated to a temperature of 250"C.
．． Sodium 5-diaminobenzenesulfonate 12.6
y < o, os mol), 10.0 f (0.06 mol) of 4,4'-diaminodiphenyl ether, 147 f of N-methyl-2-pyrrolidone, and 6 f of xylene as a dehydration azeotropic solvent were charged, and the mixture was heated to about -70°C. The mixture was heated to 180-200" under a nitrogen stream to dissolve it uniformly.
The reaction was carried out at a temperature of C for 20 hours. During this time, water 71 was removed by azeotropy.

After the reaction is completed, xylene is distilled off, the concentration of isomorphic components is reduced, and the
%, a viscosity of 1'240 poise, an imidization rate of 99% or more, and an intrinsic viscosity of 0.68. This polyimide is
It consists of a 50-mol unit that becomes substantial and a 50-mol unit that becomes .

This polyimide skeleton was diluted with NMP to less than 10% by weight, and then gradually added to methanol that was vigorously stirred in a household mixer to obtain a powdered polyimide.

Production Example 2 Sodium 3.5-diaminobenzenesulfonate Replaced with sodium benzidine-2,2'-disulfonate 1
G, 41 (0.05 mol) was used, and the reaction time was 19 hours, except that 1. solid content concentration 20 weight 2. imidization rate 99% or more, intrinsic viscosity 0. 6
Polyimide No. 9 was obtained. This polyimide consists essentially of 50 mole percent of units and 507 mole percent of OO units.

This polyimide solution was treated in the same manner as in Production Example 1 to obtain polyimide powder.

Example 1 The polyimide powders obtained in Production Examples 1 and 2 above were each treated with hydrochloric acid to convert the sodium sulfonate groups of the polyimide into free sulfonic acid groups, and then If was changed to a 10009Ixn aqueous solution of cobalt nitrate K at 30°C. at 24
Soaked under shaking for an hour.

After heating, the cobalt ion exchange capacity of the resin was determined by measuring the residual cobalt ion concentration in the aqueous solution using atomic absorption spectrometry. The results are shown in Table 1.

Next, separately, a powdered ion exchange resin of the present invention and a commercially available ion exchange resin (Amberlite IRO-50 manufactured by Tokyo Organic Chemical Industry ■, methacrylic acid carboxyl group type)
After heating each 1f in hot water at 20 G° C. in an autoclave for 6 days, the cobalt ion exchange capacity was determined in the same manner as above. The results are shown in Table 181.

It is clear from Table 1 that the ion exchange resin of the present invention has excellent heat resistance. On the other hand, it was observed that some of the commercially available ion exchange resins were melted due to heat treatment.

Example 2 The polyimide solution obtained in Production Example 1 was layered at 101:.

After diluting the nonionic surfactant by weight, add 0.01% of the nonionic surfactant.
Add it in the form of droplets to the ion-exchanged water containing the weight, and add it to the particle size 10
~15μ porous beaded polyimide was obtained. These beads were further immersed in ion-exchanged water at room temperature for one hour to completely remove the brown color from the polyimide resin, and then separated from the polyimide resin to obtain an ion-exchange resin in the form of porous beads.

This ion exchange resin and the same commercially available ion exchange resin as above were packed into a pressure-resistant metal column that can be heated from the outside, and after passing hot water at 200°C at a space velocity of 51/hour, Cobalt ion exchange capacity was determined in the same manner. The results are shown in Table 2.

Table 2 Similar to Example 1, the ion exchange resin of the present invention retains its cobalt ion exchange capacity even after heat treatment.
It was observed that some of the commercially available ion exchange resins were melted by heat treatment, and the ion exchange capacity was significantly reduced.

Claims (1)

[Claims] (11 General formula (where R1 represents a divalent organic group. J, which may contain a structural unit, and a sulfone represented by the general formula (wherein R3 is (m+23 a slight aromatic group, -801M is -80sH or a metal salt thereof, and m is an integer from 1 to 4) It has as a repeating unit an amic acid structural unit (which may contain an amic acid structural unit which is a precursor structure of the unit (t)), and the unit (g) or the total amount of units is
Consisting of a substantially linear polyimide that occupies 90 mol 2 and has an imidization rate defined by [number of imide rings / (number of imide rings + number of amic acid structures)] of 70% or more. Ion exchange resin. (2) The battery consists essentially of the unit (2) and the unit (to), and the unit (to) is 5 to 90 of the total amount of the unit.
The ion exchange resin according to claim 1, characterized in that it contains a mole. (3) Polyimide or substantially unit (2) and unit (to)
and 20 to 70 of the unit (to) or the total amount of the unit
The ion exchange resin according to claim 2, characterized in that it contains 6 molar fractions. 141 R1 (however, X represents a carbon-carbon bond or a divalent organic bonding group.
p and q are integers from O to 4, and p+q=m. ) Claims 1 to 3 are characterized in that:
The ion exchange resin according to any one of the above.