JPS6411335B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a cation exchanger having excellent chemical resistance and heat resistance. Hitherto, few attempts have been made to graft an organic fluorine-based monomer containing a fluorine-containing vinyl group in its molecule to an inorganic polymer. The present inventors have continued research in the field of organic fluorine chemistry for many years. The most important feature of organic fluorine compounds is that they have excellent chemical resistance and heat resistance. Another characteristic of organic fluorine-based organic acids, such as organic fluorine-based carboxylic acids, is that they exhibit strong acidity with a PKa of 2 or less. The present inventors focused on the characteristics of these organic fluorine compounds and conducted intensive research to develop an inorganic polymer containing an organic fluorine-based ion exchange group that has excellent chemical resistance and heat resistance. I've been piling it up. However, organic fluorine-based monomers containing fluorine-containing vinyl groups have significantly poor polymerizability due to their bulky fluorine atoms compared to hydrocarbon monomers with the corresponding structure, and only a limited number of monomers can be used. It has the disadvantage that it only polymerizes under very limited conditions. Furthermore, since organic fluorine-based monomers exhibit strong water repellency, they also have the disadvantage of having no affinity with inorganic polymers. That is, the grafting of organic fluorine-based monomers and inorganic polymers is extremely difficult, so that very little research has been conducted to date.
As a result of extensive research into the grafting reaction between organic fluorine-based monomers and inorganic polymers, the present inventors found that
Surprisingly, we have found that this grafting reaction proceeds easily under radiation irradiation. The inventors conducted further detailed research,
We have finally succeeded in producing an ion exchanger containing an organic fluorine-based ion exchange group based on an inorganic polymer, and have completed the present invention. That is, the present invention provides at least one group selected from the group consisting of a cation exchange group, a functional group that can be easily exchanged into a cation exchange group, and an organic group that can introduce a cation exchange group, and a fluorine-containing group. When grafting an organic fluorine-based monomer containing a vinyl group in the molecule to an inorganic polymer comprising silicon oxide or aluminum oxide or a silicon polymer having an organic group, the inorganic polymer is irradiated with radiation. This is a method for producing a cation exchanger, which comprises grafting an organic fluorine-based monomer onto a silicon polymer having a body or an organic group, and adding a cation exchange group as necessary. The organic fluorine-based monomer used in the present invention contains in its molecule an ion exchange group, a functional group that can be easily converted into an ion exchange group, or an organic group that can introduce an ion exchange group, and a fluorine-containing vinyl group. It is. The above-mentioned ion exchange group or a group capable of imparting an ion exchange group through post-treatment is a necessary group for the object of the present invention to be an ion exchanger, and is not particularly limited as long as it can become an ion exchanger as a result. It may be any ion exchange group or one that can be converted into an ion exchange group by post-treatment. Since the target product obtained in the present invention is a cation exchanger, the above ion exchange group needs to be a cation exchange group. As the cation exchange group, known ones can be used, and representative examples that are generally preferably used include sulfonic acid group,
These include carboxylic acid groups, other cation exchange groups, and salts thereof such as sodium, potassium, and ammonium. Examples of functional groups that can be easily converted into ion exchange groups include:

[Formula] or

[Formula] (wherein, X is a fluorine atom or a trifluoromethyl group, and Y is a chlorine atom, a fluorine atom, or OR (provided, R is an alkyl group)). The above alkyl group is preferably an alkyl group having 1 to 5 carbon atoms. These functional groups can be converted into ion exchange groups such as carboxylic acid groups, sulfonic acid groups, or alkali metal or ammonium salts thereof, for example, by hydrolysis. Furthermore, organic groups into which ion exchange groups can be introduced include, for example, benzene rings,

[Formula] (where A is a hydrogen atom, a fluorine atom, a trifluoromethyl group, etc.) or -O-
Organic groups such as CF=CF ₂ can be suitably used. A sulfonic acid group can be easily introduced into the benzene ring by, for example, treatment with concentrated sulfuric acid, chlorosulfonic acid, etc. and hydrolysis if necessary. An ion exchange group can be added by oxidation or by reacting with an ion exchange group or a compound having a functional group that can be easily converted into an ion exchange group, and if necessary converting it into an ion exchange group by post-treatment. can. Furthermore, when the organic fluorine-based monomer does not have a fluorine-containing vinyl group, no graft reaction occurs. Therefore, in the present invention, it is necessary to have a fluorine-containing vinyl group. The fluorine-containing vinyl group is not particularly limited as long as it is a known fluorine-containing vinyl group. In particular, generally preferred fluorine-containing vinyl groups include, for example:

[Formula] (where A is a hydrogen atom, a fluorine atom, or a trifluoromethyl group), and the above group may be bonded directly to carbon, or may be bonded to carbon through another atom such as oxygen. good. More specific examples of the organic fluorine monomers preferably used in the present invention are as follows.

【formula】

CF ₂ = CF (-CF ₂ ) - _l CF = CF ₂ ,

【formula】

【formula】

【formula】

【formula】

[Formula] However, Y in the above formula is a fluorine atom, a chlorine atom,
or OZ (Z is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, ammonium, or an alkali metal), and n=0 to 8, l=0 to 8, and m=2 to 10. The organic fluorine monomer used in the present invention can be used alone, or two or more organic fluorine monomers can be used in combination. Furthermore, these organic fluorine-based monomers can also be used in combination with a highly polymerizable monomer such as tetrafluoroethylene. Furthermore, such organic fluorine monomers are
It can be used as it is, or it can be used with a solvent or dispersant added if necessary. The solvent is preferably one that is stable to radiation, and can be used without particular restrictions as long as the organic fluorine monomer can be dissolved.
Organic fluorine-based solvents that are good solvents for organic fluorine-based monomers, such as 1,1,2-trichloro-trifluoroethane, fombrine oil (trade name), perfluorokerosene, and the like are preferred. The inorganic polymer used in the present invention preferably has silicon oxide or aluminum oxide as a constituent, and silicon oxide or aluminum oxide bonded with other organic groups or metal oxides are also preferably used. . Typical inorganic polymers that are generally preferably used include silica gel, alumina, asbestos, and glass. Furthermore, as the silicon polymer having an organic group (hereinafter simply referred to as an organosilicon polymer) used in the present invention, known ones can be used, and examples of commonly used silicon polymers include polysilane, polysiloxane, polysilazane, and polymetallosiloxane. , polysilmethylene, polysilphenylene, polysilphenylene siloxane, and other silicon polymers. The shape of these inorganic polymers or organosilicon polymers is not particularly limited, but powder, sheet, porous film, fiber, bead, and the like are preferably used. In terms of graft reaction efficiency, it is generally preferable to use a material with a large surface area per unit weight. The most important feature of the present invention is that when the organic fluorine monomer is grafted onto an inorganic polymer or an organosilicon polymer containing silicon oxide or aluminum oxide, the inorganic polymer or organosilicon polymer is grafted by irradiation with radiation. The method involves grafting the organofluorine monomer onto an organosilicon polymer. The type of radiation mentioned above is not particularly limited, and known ones such as α, β, and γ rays are preferable, and γ rays are particularly preferable. The radiation dose in the present invention is not particularly limited, but the optimum dose may be determined depending on various factors such as the efficiency of the graft and the stability of the organic fluorine compound against radiation. types, irradiation dose rate, types of organic fluorine monomers, types of inorganic polymers, etc. Usually 0.01~100Mrad, preferably 0.20
It is preferable to select from the range of ~50 Mrad. The method of grafting the organofluorine monomer to the inorganic polymer or organosilicon polymer in the present invention is not particularly limited and any method may be employed, but in general, the inorganic polymer or organosilicon polymer is grafted with radiation. A method of contacting the inorganic polymer or organosilicon polymer with an organic fluorine-based monomer after irradiating the inorganic polymer or organosilicon monomer with the organic fluorine-based monomer; A method of irradiating the light with a light source, etc. is preferably adopted. Although the mechanism by which the above-mentioned grafting reaction proceeds is still unclear, the present inventors have discovered that active radicals are generated when the inorganic polymer or organosilicon polymer is irradiated with radiation, and that these active radicals are It is presumed that the organic fluorine monomer reacts with the action. Generally, in the grafting reaction, as the radiation dose increases, the amount of organic fluorine-based monomer grafted onto the surface of the inorganic polymer or organosilicon polymer increases, as is clear from the examples described later. There is a tendency. Of course, at this time,
Some organic fluorine-based monomers may cause graft polymerization. For example, when grafting is carried out in the coexistence of tetrafluoroethylene, the surface of the inorganic polymer or organosilicon polymer becomes coated with the organic fluorine-based polymer. That is, a copolymer or block polymer of an organic fluorine monomer and tetrafluoroethylene is formed on the surface of the inorganic polymer or organosilicon polymer. In addition to tetrafluoroethylene, compounds such as perfluoroalkoxyvinyether [general formula CF ₂ = CF-O-B (where B is CF ₃ ,
The same applies when a perfluoroalkyl group such as a C ₂ F ₅ or C ₃ F ₇ group is present. After the graft reaction product produced by the above reaction is separated and removed by appropriate means such as extraction, evaporation, filtration, washing, etc., unreacted organic fluorine monomers and by-products are removed, and then the necessary An ion exchange group may be introduced depending on the requirements. The method for introducing the ion exchange group is not particularly limited, and may be carried out by known methods such as hydrolysis or post-treatment with sulfuric acid, chlorosulfonic acid, or the like. As explained above, the ion exchanger of the present invention can be obtained by grafting an organic fluorine-based monomer onto an inorganic polymer or an organosilicon polymer by the extremely simple means of radiation irradiation. Even if the grafted product is extracted with a solvent that dissolves the organic fluorine monomer or its polymer, such as 1,1,2-trichlorotrifluoroethane, the organic fluorine monomer or its polymer cannot be separated. It has become an incredibly strong bond. The ion exchanger obtained in the present invention has excellent chemical resistance and heat resistance. Therefore, the ion exchanger can be used without being limited to known applications as an ion exchanger, and in particular can be used as a diaphragm for electrolysis, a solid catalyst such as a solid alkylation catalyst having a strongly acidic ion exchange group, and water for olefins. Widely used as a catalyst. EXAMPLES In order to explain the present invention more specifically, the present invention will be described below with reference to Examples, but the present invention is not limited to these Examples. Example 1 1.0 g of silica gel (35-70 mesh) was placed in a glass ampoule with a diameter of 8 mm, and perfluorosulfonic acid monomer was added. was added until the silica gel was immersed, and the tube was sealed.
Gamma rays from C ₀ ⁶⁰ were applied to this sealed tube sample at a dose rate of
It was irradiated for 123 hours at 2.0×10 ⁴ (rad/hr) for a total irradiation dose of 2.5 Mrad. After irradiation, take out the sample and add water and 1,
Unreacted monomers and soluble components were extracted and removed with 1,2-trichlorotrifluoroethane for several hours each. The exchange capacity of the thus obtained graft product insoluble in the solvent was measured by titration and was found to be 1.3 meq/g. Example 2 Organic fluorine monomers and inorganic polymers are shown in Table 1.
Various organic fluorine-based monomers were grafted onto various inorganic polymers and post-treated in the same manner as in Example 1, except for the following changes. During the post-treatment -COF group, -COCl group, _-SO2F group,
In the case of an organic fluorine monomer having ₅ -CO ₂ C ₂ H groups, the soluble portion was removed by decantation after stirring in 1N-NaOH at 60°C for 5 hours, and the product was acidified with hydrochloric acid. Obtained.

[Table] Example 3 By the same method as Example 1,

A mixture of [Formula] and 2.3 g (35 to 70 mesh) of silica gel was irradiated with C ₀ ⁶⁰ γ-rays at a total dose of 2.0 Mrad. After irradiation, soluble components such as unreacted monomers were extracted and removed in the same manner as in Example 1. The resulting grafted product was then immersed in concentrated sulfuric acid at 60°C for 3 hours to effect sulfonation and introduce ion exchange groups. The presence of sulfonyl groups can be determined by quantitative determination of sulfur by elemental analysis and by infrared absorption spectrum (IR).
This was confirmed by the appearance of absorption near 1200 cm ^-1 . The ion exchange capacity of the ion exchanger thus obtained was determined by titration.
It was 1.0meq/g. Example 4 By the same method as in Example 3, various organic fluorine monomers shown in Table 2 were grafted. Examples of soluble components such as unreacted monomers

[Table] Removed in the same manner as in 3. The resulting graft product was sulfonated using the sulfonating agent shown in Table 2 in the same manner as in Example 3. The results were as shown in Table 2. Example 5 CF ₂ =CF-O-CF ₂ -CF ₂ -O-CF=CF ₂ was added in the same manner as in Example 1 until silica gel (35 to 70 mesh; 2.3 g) was immersed, and the tube was sealed. Next, this sealed tube sample was irradiated with C ₀ ⁶⁰ γ-rays at 1.5 Mrad. The resulting grafted product was washed with 1,1,2-trichlorotrifluoroethane. Then, using a UV lamp (Toshiba mercury lamp SHL-100UV2),
By irradiating the grafted product with ultraviolet rays for 8 hours in air at a temperature of 0.degree. C., mainly vinyl groups remaining in the grafted product were oxidized with oxygen to generate carboxyl groups.
That is, the oxidation product is 1780 cm ^-1 by IR measurement.
It showed absorption derived from CF ₂ COOH group. The exchange capacity of the ion exchanger obtained in this way is
It was 0.8meq/g. Example 6 For the purpose of examining the solvent used in the grafting reaction, grafting was carried out under the same reaction conditions as in Example 2-6 in the presence of the various solvents shown below. The results are shown in Table 3.

[Table] Example 7 A graft reaction was carried out in the same manner as described in Example 1, except that the radiation shown in Table 4 was used. The results are shown in Table 4.

[Table] Example 8 A graft reaction was carried out under exactly the same conditions as described in Example 1, except that during radiation irradiation, the dose was varied as shown in Table 5. The relationship between the irradiation dose and the ion exchange capacity of the grafted product was as shown in Table 5.

[Table] Example 9 Silica gel (35 to 70 mesh; 2.1 g) was placed in a glass ampoule, degassed, sealed, and irradiated with γ-rays of 2 Mrad. Then put it in a thick Teflon container. The above ampoule and iron ball were placed in the ampoule, and after degassing, the mixture was sealed and shaken vigorously. The grafted product was then allowed to stand for about 8 hours, removed from the Teflon container, and subjected to the same post-treatment as described in Example 1. The graft product thus obtained had the same properties as those obtained in Example 1, and the exchange capacity was 1.2 meq/g. Example 10 Silica gel (35~
70mesh; 10.0g) 20 ml was added to dissolve the tetrafluoroethylene therein, and the ampoule was sealed at a gauge pressure of 3 kg/cm ² . When the sealed ampoule was irradiated with γ-rays at 0.5 Mrad, the exchange capacity of the resulting graft product was
0.4meq/g, weight increase rate ({weight after grafting (g) - original sample (g)}/original sample (g) x 100
[%]) was 35%. Example 11 The graft reaction and post-treatment were carried out under the same conditions as in Example 10, except that tetrafluoroethylene was not used. The exchange capacity of the resulting grafted product is
It was 0.3meq/g, and the weight increase rate was 20%. Example 12 CF ₂ =CF− instead of tetrafluoroethylene
The graft reaction and post-treatment were carried out under the same conditions as in Example 10, except that O-C ₃ F ₇ (20 ml) was used.
The exchange capacity of the obtained grafted product is 0.4meq/
g, and the weight increase rate was 33%. Example 13 Trichlorophenylsilane was hydrolyzed in a dilute aqueous hydrochloric acid solution, and the obtained phenylsilsesquioxane was ground in an agate mortar to form a fine powder of 100 mesh or more. 5.0g of the above fine powder was mixed with perfluorosulfonic acid monomer. A glass ampoule immersed in 5 ml was prepared in the same manner as in Example 1. This glass ampoule was irradiated with 2.2 Mrad of gamma rays,
The resulting grafted product was subjected to the same post-treatment as described in Example 1. The exchange capacity of the grafted product thus obtained was 1.3meq/
It was hot at g. Example 14 Silica gel (35-70mesh; 2.0g) was prepared using the formula The sample was immersed in a solution in which 30 parts by weight of sodium perfluorocarboxylate represented by was dissolved in 70 parts by weight of degassed pure water, and irradiated with 3 Mrad of γ-rays. The resulting grafted product had an exchange capacity of 0.85 meq/g. Example 15 Organic fluorine monomer The graft reaction and post-treatment were carried out in the same manner as in Example 14, except for the following. The resulting product had an exchange capacity of 0.80 meq/g. Example 16 The organic fluorine monomer is CF ₂ =CF−(CF ₂ −) ₅ CF=
The graft reaction, post-treatment, and ultraviolet irradiation were carried out in the same manner as in Example 5, except that CF ₂ was used. The product is −CF ₂ − at 1780 cm ⁻¹ in IR measurement.
It showed absorption derived from CO ₂ H group. The exchange capacity of the ion exchanger obtained in this way is
It was 0.8meq/g. Reference example 1 The organic fluorine monomer was irradiated with γ-rays at 3 Mrad. After irradiation, the solubility of the sample in various solvents was examined. As a result, it was found to be easily soluble in 1,1,2-trichlorotrifluoroethane, fombin oil, perfluorokerosene, and tetrahydrofuran. Reference example 2 Then, γ-rays were irradiated at 3 Mrad. This one is 1,
It was easily soluble in 1,2-trichlorotrifluoroethane, fombin oil, and perfluorokerosene.

Claims (1)

[Scope of Claims] 1. At least one group selected from the group consisting of a cation exchange group, a functional group that can be easily converted into a cation exchange group, and an organic group that can introduce a cation exchange group, and a cation exchange group. When grafting an organic fluorine-based monomer containing a vinyl group in its molecule to an inorganic polymer containing silicon oxide or aluminum oxide or a silicon polymer having an organic group, the inorganic A method for producing a cation exchanger, which comprises grafting an organic fluorine-based monomer onto a polymer or a silicon polymer having an organic group, and optionally imparting a cation exchange group. 2. The method according to claim 1, wherein the inorganic polymer is silica gel, alumina, asbestos, or glass. 3 A functional group that can be easily converted into a cation exchange group has the general formula: [Formula] [Formula] , Z is a hydrogen atom, an alkyl group, ammonium or an alkali metal). 4. The organic group into which a cation exchange group can be introduced is a benzene ring, [Formula] (where A is a hydrogen atom, a fluorine atom, or a trifluoromethyl group), or -
The method according to claim 1, wherein O-CF= _CF2 is an organic group. 5. The method according to claim 1, wherein the containing fluorine vinyl group is [Formula] (wherein A is a hydrogen atom, a fluorine atom, or a trifluoromethyl group).