TW202111161A - Method and device for producing quaternary ammonium hydroxide - Google Patents

Abstract

A method for producing quaternary ammonium hydroxide in an electrolysis vessel configured so that a negative ion exchange film and a positive ion exchange film are arranged between electrodes, the method being performed by supplying an aqueous solution of quaternary ammonium halide to a chamber partitioned by the negative ion exchange film and the positive ion exchange film and performing electrolysis, wherein the method for producing quaternary ammonium hydroxide is characterized in that electrolysis is performed by using, as the negative ion exchange film, a film in which a proton-transmission-suppressing layer comprising a high-crosslinking resin layer, etc., is formed on a film surface on one side, the film being used in a state in which the surface where the proton-transmission-suppressing layer is formed is arranged so as to face the negative-electrode side.

Description

Manufacturing method and manufacturing device of quaternary ammonium hydroxide

The present invention relates to a method and device for producing quaternary ammonium hydroxide by electrolysis using ion exchange membranes.

The quaternary ammonium hydroxide represented by tetramethylammonium hydroxide is used as a phase transfer catalyst, a standard solution of alkali in non-aqueous solvent titration, and an organic alkali agent, etc., used for the conduct or analysis of various chemical reactions, etc. In the compound. In addition, recently, when manufacturing IC (integrated circuit) and LSI (Large Scale Integration), it is widely used as a processing agent for manufacturing semiconductor substrates, developing resists, and the like.

Quaternary ammonium hydroxide requires less impurities and high purity, especially when used in the semiconductor manufacturing process, the requirements are relatively high. In recent years, semiconductor devices have significantly increased their integration. It is known that when semiconductor substrates are manufactured using a developer containing low-purity quaternary ammonium hydroxide, etc., leakage in the high-integration circuit will cause defective products. The rate becomes higher.

As a method for producing high-purity quaternary ammonium hydroxide, a method of electrolysis using quaternary ammonium halide (specifically, tetramethylammonium chloride) as a raw material is known (see Patent Document 1). In this method, an anion exchange membrane and a cation exchange membrane are arranged between the electrodes, and an aqueous solution of quaternary ammonium halide is supplied to a chamber (raw material chamber) separated by the anion exchange membrane and the cation exchange membrane to perform electrolysis. In this manufacturing method, quaternary ammonium ions pass through a cation exchange membrane arranged on the cathode side and move to a caustic chamber (cathode chamber) supplied with water, where quaternary ammonium hydroxide is generated in a high concentration.

In the production method of quaternary ammonium hydroxide by such electrolysis, the halide ions (specifically chloride ions) in the raw material compartment pass through the anion exchange membrane separating the anode side and move to the anode compartment by the following _{^{formula: 2X - → X 2 + 2e}} - the electrode reaction shown halogen gas (e.g. chlorine).

At this time, the above-mentioned anion exchange membranes usually use the following composite membranes: a polymerizable composition that becomes the precursor of an anion exchange crosslinked resin is coated on a high-void substrate for polymerization, and anion exchange groups are introduced as necessary. . It has also been proposed to use the following anion exchange membrane as appropriate: in order to impart degradation resistance to hypohalous acid (such as hypochlorous acid) generated in the anode compartment, an anion layer with high oxidation resistance is provided on the surface of the membrane Exchange membrane (for example, refer to Patent Documents 2 and 3). When used in the case of an anion exchange membrane with an oxidation resistant layer provided on the membrane surface, in order to impart deterioration resistance in contact with hypohalous acid contained in the anolyte, this arrangement inevitably makes the oxidation resistant layer face Anode side (Patent Document 2, page 3, upper left column, lines 7-12, Patent Document 3, claim 1). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 1-87793 [Patent Document 2] Japanese Patent Laid-Open No. 1-87796 [Patent Document 3] Japanese Patent Laid-Open No. 2009-13477

[The problem to be solved by the invention]

Of course, although the anion exchange membrane has the properties of allowing anions to pass through and it is difficult to pass cations, nevertheless, compared with other metal cations, protons can easily pass through. Therefore, when quaternary ammonium hydroxide is produced by the above-mentioned electrolysis, it is inevitable that a certain amount of protons will pass through the anion exchange membrane and move from the anode chamber to the raw material chamber side. Therefore, the current efficiency is reduced.

According to research conducted by the inventors, this phenomenon does not fundamentally change when a membrane with an oxidation-resistant layer formed on the surface of the membrane is used as the anion exchange membrane. That is, the reason is that although the oxidation-resistant layer on the surface of the film may also have the effect of inhibiting the passage of protons, even in this case, the oxidation-resistant layer is arranged so as to face the anode side as described above. As an anion exchange membrane, although the proton permeation suppression effect is exerted at the beginning of electrolysis, if it is operated continuously for a long time, even if the surface of the membrane is an oxidation-resistant layer, it will gradually be affected by oxidative degradation and gradually lose the protons mentioned above. Through the suppression effect.

Based on the above background, the purpose of the present invention is to develop a production method of quaternary ammonium hydroxide using electrolysis, which can highly inhibit the permeation of protons from the anode chamber to the raw material chamber, and maintain the above-mentioned production well even if the production is continued for a long time. This penetration suppression effect makes it possible to stably manufacture the above-mentioned target with excellent current efficiency. [Technical means to solve the problem]

In view of the above-mentioned problems, the present invention continues to make intensive research. As a result, it was found that a membrane with a proton permeation inhibiting layer formed on one side of the membrane is used as an anion exchange membrane, and the membrane is arranged such that the surface on which the proton permeation inhibiting layer is formed faces the cathode side, thereby achieving good The above-mentioned problems have been solved, and the present invention has been completed.

That is, the present invention relates to a method for producing quaternary ammonium hydroxide, which is in an electrolytic cell composed of an anion exchange membrane and a cation exchange membrane arranged between the electrodes, and supplies halogenation to a chamber separated by the anion exchange membrane and the cation exchange membrane. A method of electrolyzing an aqueous solution of quaternary ammonium to produce quaternary ammonium hydroxide; The manufacturing method is characterized in that: a membrane with a proton permeation suppression layer formed on the surface of the membrane on one side is arranged so that the surface on which the proton permeation suppression layer is formed faces the cathode side, and the film is used as The above-mentioned anion exchange membrane performs electrolysis.

In addition, the present invention relates to a quaternary ammonium hydroxide production device, which is to arrange an anion exchange membrane and a cation exchange membrane between the electrodes, and supply an aqueous solution of quaternary ammonium halide to a compartment separated by the anion exchange membrane and the cation exchange membrane. Conduct electrolysis to produce a device for quaternary ammonium hydroxide; The manufacturing device is characterized in that the anion exchange membrane is provided with a proton permeation suppression layer on the cathode side surface.

As mentioned above, in order to protect the anion exchange membrane from the hypohalous acid generated in the anode compartment, an oxidation resistant layer was provided on the anode side surface of the anion exchange membrane. That is, since the oxidation resistant layer was previously provided on the cathode side, the anion membrane could not be protected from the hypohalogenous acid generated in the anode chamber, so the oxidation resistant layer was provided on the anode side surface of the anion exchange membrane. However, it is not considered that the oxidation resistant layer is provided on the cathode side. On the other hand, under the new concept of suppressing the penetration of protons from the anode chamber to the raw material chamber in the present invention, a proton-permeation suppression layer is unimaginably provided on the cathode side of the anion exchange membrane in the previous ideas, thereby being able to achieve long-term excellent current efficiency Stable production of quaternary ammonium hydroxide. [Effects of Invention]

According to the present invention, in the production method of quaternary ammonium hydroxide using electrolysis, the penetration of protons from the anode chamber to the raw material chamber can be highly suppressed, thereby operating with excellent current efficiency. Moreover, even if the operation is continued for a long time, the proton permeation suppression effect can be maintained well. Therefore, as a stable manufacturing method of quaternary ammonium hydroxide, the industrial use value of the present invention is extremely great.

In the electrolysis apparatus shown in the schematic explanatory diagram of FIG. 1, between the anode 1 and the cathode 2, an anion exchange membrane A is arranged on the anode side, and a cation exchange membrane C1 is arranged on the cathode side. Thereby, the raw material chamber 5 is formed between the anion exchange membrane A and the cation exchange membrane C1, and the anode chamber 4 is formed between the anion exchange membrane A and the anode 1. In addition, a cathode chamber 6 is adjacent to between the cation exchange membrane C1 and the cathode 2.

In the manufacturing method of the present invention, the electrolysis device constructed as described above is used to supply an aqueous solution of quaternary ammonium halide used as a raw material to the raw material chamber 5, to supply an acidic aqueous solution to the anode chamber 4, and to supply hydroxide to the cathode chamber 6. Aqueous solution of quaternary ammonium. Then, in this state, a specific voltage is applied between the anode 1 and the cathode 2, and electrolysis is performed at a specific current density.

In addition, as shown in FIG. 2 showing other aspects of the present invention, in an electrolysis device, for the purpose of improving the durability of the anion exchange membrane A, a cation exchange membrane C2 may be arranged between the anode 1 and the anion exchange membrane A. . In this case, acid is generated in the acid chamber 7 between the cation exchange membrane C2 and the anion exchange membrane A, and pure water is supplied to keep the concentration constant.

Among the electrodes used in the above-mentioned electrolysis device, the anode can be used without limitation as an electrode that is stable in an oxidizing atmosphere. For example, carbon, a titanium plate coated with platinum, and an insoluble anode in which Ru, Ir, etc. are coated on a titanium plate can be cited. On the other hand, the cathode can be used without limitation in a stable and low-voltage electrode under a strong alkaline atmosphere. For example, insoluble active cathodes for salt electrolysis, such as SUS316, platinum plates, and nickel plates coated with platinum, can be cited. The shape of the electrodes can be plate-shaped, mesh-shaped, curtain-shaped, and other well-known shapes without limitation.

Furthermore, as the cation exchange membrane used in the above-mentioned electrolysis device, it may be a well-known one, for example, one having a structure in which the voids of the above-mentioned high void substrate are filled with a cation exchange resin. The above-mentioned cation exchange resin is preferably one having a hydrocarbon-based or fluorine-based resin introduced, and particularly from the viewpoint of acid resistance, alkali resistance, etc., a fluorine-based resin such as a perfluorocarbon-based resin is preferably used.

In the present invention, a quaternary ammonium salt as raw materials, for example, the following general formula (1) is represented ^{_{by: [R 4 N +] ·}} X - (1) ( wherein, R represents an alkyl, hydroxyalkyl Group or aryl group, the 4 Rs may be the same group or different groups, X is a halogen). Among the groups represented by R, the alkyl group is preferably one having 4 or less carbon atoms such as methyl, ethyl, propyl, and butyl. The hydroxyalkyl group is preferably a hydroxy substituent of the above-mentioned alkyl group. The aryl group is preferably one having 6 to 7 carbon atoms such as phenyl, benzyl, and tolyl. The halogen may be any of chlorine, bromine, fluorine, etc., and is usually chlorine or bromine.

As representative examples of the quaternary ammonium salt, tetramethylammonium halide, tetraethylammonium halide, tetrapropylammonium halide, tetrabutylammonium halide, and the like can be cited.

With the manufacturing method of the present invention, the quaternary ammonium salt in the general formula (1) as the starting material for producing the following general formula (2) is of a quaternary ammonium ^{_{hydroxide: [R 4 N +] ·}} OH - (2 ) (In the formula, R is the same as that shown in the above general formula (1)). For example, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. are produced.

Hereinafter, the principle of the present invention will be explained by using tetramethylammonium chloride (TMAC) as a raw material as shown in FIGS. 1 and 2 and supplying it to electrolysis to produce quaternary ammonium hydroxide.

The above-mentioned TMAC aqueous solution is supplied to the raw material chamber 5, while the acid aqueous solution is supplied to the anode chamber 4 and the acid chamber 7, and then the tetramethylammonium hydroxide (TMAH) aqueous solution is supplied to the cathode chamber 6. In this state, the anode 1 A specific voltage is applied between the cathode and the cathode 2. The current density is preferably 1-50 A/dm ² , and the temperature in the electrolysis device is preferably maintained at no more than 90°C. It is desirable that the concentration of the quaternary ammonium salt supplied to the raw material compartment 5 is usually 0.2 to 5.0 equivalents, more preferably 1.0 to 4.0 equivalents. When the concentration is too low or too high, the conductivity of the liquid becomes lower and the resistance of the solution becomes larger, so the efficiency of electrolysis decreases.

When the electrolysis described above, tetramethylammonium ions (TMA ⁺⁾ cation exchange membrane Cl, feed chamber 5, the following expression occurs from the cathode 2 move to the cathode chamber _{^{6: TMA + + H 2 O +}} e - → The electrode represented by TMAH+1/2H ₂ reacts to obtain tetramethylammonium hydroxide (TMAH). Although an aqueous solution of quaternary ammonium hydroxide is supplied to the cathode chamber, if the concentration of the quaternary ammonium hydroxide becomes higher, the current efficiency will decrease. Therefore, it is generally preferable to adjust the quaternary ammonium hydroxide to 0.1 to 4.5 equivalents.

In FIG. 1, the chloride ions (Cl ⁻ ) in the raw material compartment 5 pass through the anion exchange membrane A and move to the anode compartment 4. To the anode chamber 4, Cl ^- by the following _{^{equation: 2Cl - → Cl 2 + 2e}} - represented by the electrode reaction becomes chlorine gas (Cl _2). As the acid used in the anode chamber 4, inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, or organic acids such as formic acid and acetic acid are used. The concentration of the acid is in the range of 0.05-3.0 equivalents. Especially in order to keep the current efficiency of the anion exchange membrane A high, it is preferable to use 0.1-1.0 equivalents of acid. Furthermore, the current efficiency of the anion exchange membrane A described herein refers to the ratio of halide ions in the ions that pass through the anion exchange membrane A. In this way, since the anode chamber 4 is an acid solution, as described above, a part of it is represented by the following formula: Cl ₂ +H ₂ O→HCl+HClO, and hypochlorous acid with strong oxidizing power is generated.

As shown in FIG. 2, when the cation exchange membrane C2 is arranged between the anode 1 and the anion exchange membrane A, the Cl ^{− in the} raw material chamber 5 moves to the acid chamber 7 through the anion exchange membrane A. In addition, a dilute acid aqueous solution (for example, a sulfuric acid aqueous solution) is supplied to the anode chamber 4, and protons move to the acid chamber 7 through the cation exchange membrane C2. As a result, acid (HCl) is generated in the acid chamber 7. Use mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, or organic acids such as formic acid, acetic acid, etc. as the acid used in the acid chamber 7. The concentration is in the range of 0.05 to 3.0 equivalents, especially to keep the current efficiency of the anion exchange membrane A relatively high. High, preferably 0.1 to 1.0 equivalent of acid is used.

^{In Fig. 1, all the Cl-that has} passed through the anion exchange membrane A is supplied to the anode 1. In contrast, in Fig. 2, a ^{part of the Cl-} that has moved to the acid chamber 7 passes through the cation exchange membrane C2 to the anode due to the action of the electric field. Room 4 invaded. Therefore, as the amount of generated chlorine gas, the aspect shown in Fig. 2 is reduced.

The biggest feature of the present invention is that in the production of quaternary ammonium hydroxide using electrolysis as described above, the anion exchange membrane A is used on one side of the membrane surface with proton (H ⁺ ) permeation suppression layer 9 formed, and The membrane is arranged such that the surface on which the proton permeation suppression layer 9 is formed faces the cathode side. That is, due to the presence of the proton permeation suppression layer 9, in the production of the above-mentioned quaternary ammonium hydroxide, the permeation of protons from the anode chamber 4 to the raw material chamber 5, which is the cause of the decrease in current efficiency, is largely suppressed. In addition, the proton permeation suppression layer 9 is preferably provided as a highly cross-linked resin layer as described later, and therefore, it is inherently excellent in oxidation resistance in many cases. In addition, in the present invention, since the surface on which the proton permeation suppression layer 9 is formed faces the cathode side (in other words, faces the raw material chamber 5), this layer is in line with the hypohalogen generated in the anode chamber 4 The acid contact itself is also greatly suppressed. As a result, the above-mentioned proton permeation suppression effect of the anion exchange membrane A is well maintained, and even if the operation is continued for a long time, the problem of reduced current efficiency is greatly improved.

On the contrary, when the surface on which the proton permeation suppression layer 9 is formed faces the anode side, at the beginning of electrolysis, the proton permeation suppression effect is exerted to a certain level due to the effect of the same proton permeation suppression layer 9, but if Long-term continuous operation, the effect will gradually decrease. That is, the reason is that the oxidative degradation effect of hypohalous acid is very strong, even if the proton permeation suppression layer 9 is a highly crosslinked resin layer with excellent oxidation resistance, if it is directed toward the anode chamber, it will come into contact with hypohalous acid in a large amount. It is still unavoidable to gradually deteriorate after long-term operation under the environment.

The anion exchange membrane A includes a base layer 10 and a proton permeation suppression layer 9 formed on the membrane surface on one side of the base layer 10. Here, the proton permeation suppression layer 9 is defined as a layer having a lower proton permeability than that of the base layer 10. In the anion exchange membrane, in order to reduce the proton permeability of the membrane surface in this way, it is preferable to increase the degree of crosslinking, etc., so as to reduce the water content of affinity with the anion exchange group. Thereby, the permeability of anions can be ensured to a certain level, while the permeability of protons is relatively suppressed.

Such an anion exchange membrane A with a proton permeation suppression layer formed on the membrane surface is preferably obtained by the following method. That is, this method is based on the original membrane for introduction of anion exchange groups obtained by polymerizing a polymerizable composition containing an aromatic polymerizable monomer having a halogenated alkyl group and a crosslinkable polymerizable monomer, and the dialkylamine compound or The polyamine compound contacts the film surface on one side to form a highly crosslinked resin layer on its surface with a higher crosslinking ratio than the inside. Then, the trialkylamine is brought into contact with the remaining haloalkyl groups in the film to convert it into a quaternary ammonium group. . According to this method, in the above-mentioned original membrane for anion exchange group introduction, the haloalkyl group existing on the membrane surface part of one side is contacted with the dialkylamine compound or polyamine compound at a certain ratio and is consumed in the crosslinking process. . Therefore, the film surface portion becomes a dense structure due to crosslinking, and therefore the water content is reduced, and it becomes a layer that is particularly excellent for inhibiting proton permeation.

In this method, the above-mentioned aromatic polymerizable monomer having a halogenated alkyl group can be used without limitation. The number of carbon atoms in the alkyl group is preferably from 1 to 8, and examples of the halogen atom to be substituted include chlorine, bromine, and iodine. Such halogenated alkyl groups are chloromethyl, bromomethyl, iodomethyl, chloroethyl, bromoethyl, iodoethyl, chloropropyl, bromopropyl, iodopropyl, chlorobutyl, bromobutyl, iodine Butyl, chloropentyl, bromopentyl, iodopentyl, chlorohexyl, bromohexyl, iodohexyl, etc. Specific examples of aromatic polymerizable monomers having such halogenated alkyl groups include: chloromethyl styrene, bromomethyl styrene, iodomethyl styrene, chloroethyl styrene, bromoethyl styrene, and ethyl iodide. Butyl styrene, chloropropyl styrene, bromopropyl styrene, iodopropyl styrene, chlorobutyl styrene, bromobutyl styrene, iodobutyl styrene, chloropentyl styrene, bromopentyl benzene Ethylene, iodopentyl styrene, chlorohexyl styrene, bromohexyl styrene, iodohexyl styrene, etc., among which the use of chloromethyl styrene, bromomethyl styrene, iodomethyl styrene, ethyl chloride is particularly preferred Butyl styrene, bromoethyl styrene, iodoethyl styrene, chloropropyl styrene, bromopropyl styrene, iodopropyl styrene, chlorobutyl styrene, bromobutyl styrene, iodobutyl benzene Vinyl.

As for the original membrane for introduction of anion exchange groups obtained by polymerizing the above-mentioned polymerizable composition, it is derived from the above-mentioned aromatic polymerizable monomer having a halogenated alkyl group and has a halogenated alkyl group in the film, and the halogenated alkyl group is described later. Converted into anion exchange group, that is, quaternary ammonium group. The quaternary ammonium-based strongly basic group is particularly excellent as an anion exchange group. However, when it is desired to have anion exchange group other than this, in the polymerizable composition, in addition to the above-mentioned aromatic halogenated alkyl group In addition to the polymerizable monomer, a polymerizable monomer having another anion exchange group or a polymerizable monomer having a functional group into which another anion exchange group can be introduced may also be used in combination. The anion exchange group other than the quaternary ammonium group is not particularly limited as long as it is a functional group that can become negatively or positively charged in an aqueous solution. Examples include primary to tertiary amino groups, pyridyl groups, imidazole groups, Quaternary pyridinium group and so on.

Specific examples of such monomers having other anion exchange groups include: amino styrene, alkyl amino styrene, dialkyl amino styrene, trialkyl amino styrene, vinyl benzyl trimethyl amine , Vinylbenzyl triethylamine and other amine monomers; vinyl pyridine, methyl vinyl pyridine, ethyl vinyl pyridine, vinyl pyrrolidone, vinyl carbazole, vinyl imidazole and other nitrogen-containing heterocyclic systems Monomers, salts and esters of these monomers, etc.

In addition, as a polymerizable monomer having a functional group into which other anion exchange groups can be introduced, styrene can be suitably used, and substituents such as halogen, alkyl, or haloalkyl can be introduced into the aromatic ring or vinyl of the styrene. Into the styrene substitution body and so on. Specifically, styrene, vinyl toluene, chloromethyl styrene, etc. are mentioned. In addition, vinyl pyridine, vinyl imidazole, α-methyl styrene, vinyl naphthalene, acrylamide, vinyl pyrrolidone, methyl vinyl ketone, and the like can also be used.

In the polymerizable composition, the amount of the polymerizable monomers having other anion exchange groups or the polymerizable monomers having functional groups that can be introduced into other anion exchange groups is not particularly limited. For 100 parts by mass of the aromatic polymerizable monomer, it is preferably 100 parts by mass or less, and more preferably 50 parts by mass or less.

Furthermore, in the polymerizable composition, in addition to the polymerizable monomers used to introduce anion exchange groups into the anion exchange membrane, polymerizable monomers that do not directly participate in the introduction of such anion exchange membranes can also be prepared as needed. Examples of such polymerizable monomers that do not participate in the introduction of the anion exchange membrane include styrene, acrylonitrile, methyl styrene, acrolein, methyl vinyl ketone, and vinyl biphenyl.

In the polymerizable composition, the amount of the polymerizable monomer that does not directly participate in the introduction of the anion exchange membrane is not particularly limited, and it is preferably relative to 100 parts by mass of the above-mentioned aromatic polymerizable monomer having a halogenated alkyl group. It is 400 parts by mass or less, more preferably 150 parts by mass or less.

In the polymerizable composition, in order to increase the compactness of the obtained anion exchange membrane and increase the membrane strength, it is preferable to use a crosslinkable polymerizable monomer. As such a crosslinkable polymerizable monomer, a previously known monomer for producing an ion exchange membrane can also be used without particular limitation. Specifically, for example, meta-, p-, or o-divinylbenzene, divinyl biphenyl, divinyl sulfide, butadiene, chloroprene, isoprene, trivinylbenzene, divinyl benzene can be used Other functional vinylbenzyl compounds disclosed in naphthalene, diallylamine, triallylamine, divinylpyridine, or Japanese Patent Laid-Open No. 62-205153, etc., having 3 or more vinylbenzyl groups Wait.

If these crosslinkable polymerizable monomers are blended too much with respect to the aromatic polymerizable monomers having halogenated alkyl groups, there is a risk that not only will the ion exchange capacity of the anion exchange membrane decrease, but the degree of crosslinking may also be caused If it is too high, the membrane resistance will increase, which will increase the power consumption rate. On the contrary, if the blending ratio of the crosslinkable polymerizable monomer is too small, there is a risk that not only will the strength of the membrane be reduced, but also the degree of crosslinking is different from that of the proton permeation inhibiting layer provided on the membrane surface. The difference in the swelling rate in the state becomes too large, which may cause the proton permeation suppression layer to warp on the inside and make it difficult to handle. Therefore, it is preferable to formulate 5 with respect to 100 parts by mass of the total polymerizable monomer component including an aromatic polymerizable monomer having a halogenated alkyl group and other polymerizable monomers used in combination as necessary as described above. ~40 parts by mass, preferably 10-30 parts by mass of a crosslinkable polymerizable monomer.

In the polymerizable composition, a polymerization initiator is usually blended. The polymerization initiator can be used without any particular limitation, and can be appropriately selected in consideration of the high void base material used, molding conditions, and the like. As specific examples thereof, preferred are: p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, α,α'-bis(tert-butylperoxy m-isopropyl)benzene, di-tert-butyl Peroxide, tertiary butyl hydroperoxide, di-tertiary amyl peroxide, tertiary butyl cumyl peroxide, dicumyl peroxide, 2,5-dimethyl -2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3, cumene peroxide Hydrogen, 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethyl-2,5-dihydroperoxyhexane, 2,5-dimethyl-2,5- Hexyne-3 dihydroperoxide, benzoyl peroxide, methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexane peroxide, methyl cyclohexane peroxide, peroxide Isobutyl, 2,4-dichlorobenzyl peroxide, o-methylbenzyl peroxide, bis-3,5,5-trimethylhexyl peroxide, lauryl peroxide, p-chlorine peroxide Benzoyl, 1,1-di-tert-butylperoxy-trimethylcyclohexane, 1,1-di-tert-butylperoxycyclohexane, 2,2-di-(the Tributylperoxy)-butane, 4,4-di-tert-butylperoxyvalerate n-butyl, peroxyphenoxyacetic acid-2,4,4-trimethylpentyl, peroxide Α-Cumyl neodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, t-butyl peroxy2-ethylhexanoate, third-butyl peroxyisobutyrate Butyl ester, di-tertiary butyl peroxide hexahydroterephthalate, di-tertiary butyl peroxide azelate, tertiary butyl peroxide 3,5,5-trimethylhexanoate, third butyl peroxyacetic acid Tributyl ester, tert-butyl peroxybenzoate, etc. These alone or in a combination of two or more are added and mixed in the monomer slurry.

As for the usage amount of the above-mentioned polymerization initiator, it is usually in the range of preferably 0.1-30 parts by weight, and more preferably within the range of 1-10 parts by weight, relative to 100 parts by weight of the above-mentioned polymerizable monomer components.

In addition, in the polymerizable composition, a matrix resin can also be formulated as a viscosity modifier. By blending such a matrix resin, the coatability of the polymerizable composition can be improved, and sagging when it is applied to a substrate with high voids can be prevented.

As such a matrix resin, for example, polyvinyl chloride, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, vinyl chloride-based elastomer, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene-propylene copolymer, Saturated aliphatic hydrocarbon polymers such as polybutene, styrene polymers such as styrene-butadiene copolymers, and copolymers of the following monomers: vinyl toluene, vinyl xylene, chlorine Styrenic monomers such as styrene, chloromethylstyrene, α-methylstyrene, α-halogenated styrene, α,β,β'-trihalogenated styrene, monoolefins such as ethylene and butene, or butylene Conjugated dienes such as diene and isoprene, etc. In addition, styrene-butadiene rubber or its hydrogenated rubber, nitrile rubber or its hydrogenated nitrile rubber, pyridine rubber or its hydrogenated rubber, or styrene-based thermoplastic elastomer can also be preferably used.

Here, the styrene-based thermoplastic elastomer system polystyrene polymer and the alternating copolymer of styrene and polybutadiene, polyisoprene, vinyl polyisoprene, ethylene-butene, ethylene-propylene Alternating copolymer. For example, polystyrene-hydrogenated polybutadiene-polystyrene copolymer, polystyrene-(polyethylene/butylene rubber)-polystyrene copolymer, polystyrene-hydrogenated polyisoprene rubber can be exemplified -Polystyrene copolymer, polystyrene-(polyethylene/propylene rubber)-polystyrene copolymer, polystyrene-polyethylene-(polyethylene/propylene rubber)-polystyrene copolymer, polystyrene- Vinyl polyisoprene-polystyrene copolymer, etc. The molecular weight of the matrix resin is not particularly limited, and is usually preferably in the range of 1,000 to 1,000,000, especially 50,000 to 500,000.

In addition, the matrix resin is formulated in the polymerizable composition in an amount that can ensure a moderate viscosity according to the molecular weight. For example, the amount is preferably relative to 100 parts by weight of the polymerizable monomer component. 1 to 50 parts by weight, more preferably 3 to 15 parts by weight.

Furthermore, in the polymerizable composition, in addition to the various ingredients mentioned above, it can also be formulated as needed: dioctyl phthalate, dibutyl phthalate, tributyl phosphate, styrene oxide, or fatty acid or aromatic Plasticizers such as alcohol esters of family acids, or organic solvents, etc.

In addition, in the polymerizable composition, in order to supplement the halogen gas or hydrogen halide gas generated by the thermal decomposition of the aromatic polymerizable monomer having a halogenated alkyl group, it is also preferable to add styrene oxide or diethylene glycol. Compounds with one or more epoxy groups such as diglycidyl ether.

After the polymerizable composition composed of the above components is filled into the voids of the base material containing the high void material, polymerization is performed to obtain the original membrane for introducing anion exchange groups. As such a high-void substrate, any material known as a high-void substrate for ion exchange membranes can also be used. Generally, a support material with a porosity of 20 to 90%, and more preferably 40 to 80% is used. For example, woven fabrics, non-woven fabrics, porous films, nets, etc. formed of polyvinyl chloride, polyolefin, etc. can be cited. Among them, it is particularly preferable to use a porous membrane in terms of a method capable of obtaining a high proton permeation suppression effect without extreme increase in membrane resistance. The thickness of the high void substrate is generally selected from the range of 5 to 300 μm, and from the viewpoint of maintaining film resistance or strength, it is preferably 70 to 250 μm.

The method of filling the polymerizable composition into the high-void substrate is not particularly limited. For example, a method of coating or spraying a polymerizable composition on a high-voided substrate, or immersing a high-voided substrate in a polymerizable composition, etc. can be exemplified. When the polymerizable composition is in a paste form, it is preferably applied by coating. The filling of the high-void substrate by coating can be performed by known devices or methods such as a roll coater, a flat coater, a knife coater, a gap wheel coater, spraying, and dipping.

As described above, after the polymerizable composition is applied to the high-void substrate, it is heated and polymerized to obtain the original membrane for introducing an anion exchange group containing a film-like polymer. In order to obtain the anion exchange membrane A used in the present invention, after obtaining the original membrane for the introduction of anion exchange groups in this way, before the operation of introducing anion exchange groups, protons containing a highly crosslinked resin layer are formed on the surface of the membrane. Through the operation of the suppression layer. This forming operation can be performed by, for example, bringing a dialkylamine compound or a polyamine compound into contact with the membrane surface on one side of the original membrane for introduction of the anion exchange group.

That is, when the proton permeation suppression layer is formed only on one side of the original membrane for the introduction of anion exchange groups, the membrane surface on the other side is covered with a membrane or the like, so that the membrane surface on the side that is not covered by the membrane and the two The alkylamine compound or the polyamine compound contacts to form a highly crosslinked resin layer with a higher crosslinking ratio on the surface of the film than the inside.

The alkylamine group of the dialkylamine compound can react with the halogenated alkyl group to remove hydrogen chloride to form a quaternary ammonium group. Since the dialkylamine compound is bifunctional, it reacts with two halogenated alkyl groups to form a crosslink structure. The alkyl group of such a dialkylamine compound is preferably one having 1 to 4 carbon atoms such as methyl, ethyl, propyl, and butyl. If it shows the specific example of a dialkylamine compound, dimethylamine, diethylamine, dipropylamine, dibutylamine, etc. can be used.

Polyamine compounds are compounds that can react with halogenated alkyl groups to form quaternary ammonium groups and have two or more tertiary amine groups in one molecule. Any known polyamines can be used without limitation, preferably diamines, Triamines and tetraamines, and diamines are particularly preferred. As such diamines, alkylene diamines having 1 to 6 carbon atoms in the alkylene group are preferred. Specifically, ethylene diamine, diethylene triamine, propylene diamine, butane diamine, and pentane diamine can be used. Amine, hexamethylene diamine, tetramethyl ethylene diamine, tetramethyl hexamethylene diamine, etc.

In terms of improving the inhibition of proton permeation, the shorter the distance between the cross-linking points, the better the effect of reducing the moisture content. In this regard, it is better to use dialkylamines, and it is better not to reduce the amount of anions as much as possible. Because of its permeability, it is best to use dimethylamine.

In addition, as for the proton permeation suppression layer, the higher the reaction ratio of the haloalkyl group existing in the layer with the dialkylamine compound or polyamine compound, the more highly cross-linked resin layer can be formed, thereby becoming the permeation of protons Suppress the excellent layer. In addition, if the proton permeation suppression layer becomes thicker, the proton permeation inhibition is improved, but if it reaches a certain thickness, even if the thickness is further increased, the proton permeation inhibition hardly increases, and only the membrane resistance increases. Therefore, the preferred form of the proton permeation suppression layer is to adopt a highly cross-linked structure in which as many halogenated alkyl groups as possible react with dialkylamine compounds or polyamine compounds, and form a layer with a minimum thickness for high proton permeation suppression. . As the thickness of the proton permeation suppression layer, for example, it is preferably 50% or less of 1/2 the thickness of the anion exchange membrane, and more preferably 25% or less.

When forming such a proton permeation suppressing layer, it is preferable to perform a crosslinking reaction by contacting an aqueous solution of a dialkylamine compound or a polyamine compound. If an organic solvent is used, the affinity with the membrane is good, so it diffuses quickly into the original membrane for the introduction of anion exchange groups, and at the same time cross-links near the contact surface, it also cross-links inside the membrane. Therefore, not only the protons are cross-linked through the suppression layer, but the cross-linking also progresses to a part of the base layer, and the membrane resistance is increased more than necessary.

On the other hand, in the case of an aqueous solution, since the affinity with the membrane is lower than that of the organic solvent, the diffusion rate into the interior becomes very slow. Therefore, the crosslinking proceeds very slowly to the inside from the vicinity of the contact surface, so that the thickness of the proton permeation suppression layer can be easily controlled by taking the film out of the liquid at a specific time, and the crosslinking of the base layer can also be prevented. Furthermore, since the cross-linking reaction time of the liquid-impregnated layer is kept longer, a large amount of halogenated alkyl groups undergo cross-linking reaction, so that a layer with higher cross-linking can be formed. Therefore, it is best to form the proton permeation suppression layer by an aqueous solution.

However, when the molecular weight of the dialkylamine compound or polyamine compound is high, the diffusion rate in the aqueous solution is too slow, or the solubility is poor, in order to adjust the diffusion rate and improve the solubility, it is effective It replaces part of the water with an organic solvent. In this case, hydrophilic solvents such as methanol, ethanol, 1-propanol, 2-propanol, acetone, etc. can be used as organic solvents to replace water. The content is preferably within 30% by mass relative to water, particularly 5 to 15% by mass.

In the case of dissolving the dialkylamine compound or polyamine compound in water to perform the crosslinking reaction, the concentration is preferably 0.01 mol/L to 2 mol/L, and particularly preferably 0.03 mol/L to 1 mol/L. When the concentration is too low, the crosslinking reactivity with halogenated alkyl groups is reduced. When the concentration is too high, the diffusion inside the original membrane for the introduction of anion exchange groups is enhanced, and crosslinking to the substrate layer is likely to occur.

Furthermore, the reaction temperature is about 20-50°C. After reacting the original membrane for anion exchange group introduction with the polyamine, it is also possible to perform washing for the purpose of removing the excess dialkylamine compound or polyamine compound that has not been supplied to the reaction.

By this reaction with dialkylamine compounds or polyamine compounds, a cross-linked structure with anion exchange capacity is formed on the surface of the original membrane for anion exchange group introduction. Therefore, the original membrane for anion exchange group introduction can be used for the After the reaction, the anion exchange capacity was measured, thereby clarifying the degree of crosslinking formed on the membrane surface.

After completing the operation of forming a highly cross-linked resin layer on the membrane surface of the original membrane for the introduction of anion exchange groups, then contact the trialkylamine with the remaining haloalkyl groups in the membrane to convert them into quaternary ammonium groups. This method can be based on the conventional method of introducing quaternary ammonium groups in the manufacture of anion exchange membranes. In this case, in the above-mentioned polymerizable composition used in the production of the original membrane for the introduction of anion exchange groups, in addition to the aromatic polymerizable monomer having a halogenated alkyl group, a polymerizable composition having a functional group capable of introducing other anion exchange groups is used. In the case of monomers, the conversion of the anion exchange group corresponding to the functional group can be carried out in accordance with conventional methods. Specifically, a benzene ring such as styrene is chloromethylated, and then trialkylamine is brought into contact with it. In addition, in the case of having primary to tertiary amines, the desired anion exchange group can be introduced by a method such as quaternary amination by alkylation.

By the above method, the anion exchange membrane A can be manufactured, and a proton permeation suppression layer including a highly crosslinked resin layer is formed on the surface of the membrane on one side. In order to perform high-efficiency electrolysis with the obtained anion exchange membrane A, the anion exchange capacity is preferably 0.6-5.0 meq/g-dry membrane, especially within the range of 0.8-2.0 meq/g-dry membrane. The thickness is preferably 5 to 350 μm, especially in the range of 70 to 280 μm. That is, in order to have such physical properties, the composition of the polymerizable composition (the amount or type of monomer components or crosslinking agent), the thickness of the high void substrate, and the amount of anion exchange groups to be introduced can be appropriately set.

Furthermore, in the anion exchange membrane A obtained in this way, the anion exchange capacity of the proton permeation suppression layer is usually 0.005-0.5 meq/g-dry membrane, more preferably 0.01-0.2 meq/g-dry membrane. Here, the dry membrane used as a weight basis when determining the anion exchange capacity of the proton permeation suppression layer is the weight of the anion exchange membrane A as a whole. If the anion exchange capacity is less than this range, the permeation inhibition of protons cannot be sufficiently obtained, and if it exceeds this range, the resistance becomes high, and therefore the power consumption rate becomes high.

Furthermore, the anion exchange capacity of the proton permeation suppression layer is preferably 0.002 to 0.3 times the anion exchange capacity of the anion exchange membrane A as a whole, especially in the range of 0.005 to 0.25 times. If the ratio of the anion exchange capacity of the proton permeation suppression layer is lower than the above range, the proton permeation suppression still cannot be sufficiently obtained. Moreover, if it exceeds this range, the crosslinked layer will become too thick, it will become high resistance, and power consumption will become high.

The anion exchange capacity of the proton permeation suppression layer formed on the surface of the membrane can be determined by measuring the anion exchange capacity at the stage where the highly crosslinked resin layer is formed on the surface of the original membrane for introduction of anion exchange groups. Furthermore, in the above-mentioned polymerizable composition supplied to the manufacture of the anion exchange membrane, in addition to the aromatic polymerizable monomer having a halogenated alkyl group, a polymerizable monomer having a functional group capable of introducing other anion exchange groups is used together In the case, the introduction amount of other ion exchange groups relative to the amount of the quaternary ammonium group introduced by converting the haloalkyl group can be calculated based on the composition ratio, and based on the introduction amount, correction in the stage of forming the above-mentioned highly cross-linked resin layer The measured value of the anion exchange capacity of the original membrane used for the introduction of the anion exchange group to obtain the final anion exchange capacity of the proton permeation suppression layer. In addition, when polymerizable monomers with other anion exchange groups are used in combination, the measurement of the anion exchange capacity of the original membrane for the introduction of anion exchange groups in the step of forming the above-mentioned highly crosslinked resin layer can be measured before the In the stage before the formation of the highly cross-linked resin layer, the anion exchange capacity of the original membrane is also measured, and the measured value of the former is obtained by subtracting the measured value to obtain the anion exchange capacity of the proton permeation suppression layer. That is, the introduction amount of other ion exchange groups can be used to correct the final anion exchange capacity of the proton permeation suppression layer. The introduction amount of the other ion exchange groups is based on this value and based on the polymerizable composition supplied to the production Calculated, the introduction amount of other ion exchange groups relative to the amount of quaternary ammonium groups introduced by conversion of the above-mentioned halogenated alkyl group.

In the present invention, the above-mentioned anion exchange membrane A can not only form the proton permeation suppression layer including the above-mentioned highly crosslinked resin layer on the side facing the cathode side of the electrolytic device, but also on the opposite side facing the anode side. One side of the face. That is, a specific example of this aspect is shown in FIG. 3.

As shown in FIG. 3, the oxidation resistance of the anion exchange membrane A facing the anode side is improved, and even if it comes into contact with hypohalous acid contained in the anolyte, it is difficult to oxidize and deteriorate. As a result, the durability of the entire membrane is improved, and the continuity of the effect of the proton permeation suppression layer toward the cathode side, which is the feature of the present invention, is also greatly improved, and the quaternary ammonium hydroxide is more synergistically improved. Stable manufacturing is preferred.

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited to these examples. Furthermore, in the following examples and comparative examples, the anion exchange capacity of the anion exchange membrane and the anion exchange capacity of the original membrane for the introduction of an anion exchange group with a highly crosslinked resin layer formed on the membrane surface are measured by Measured by the following method. (Measurement method of anion exchange capacity) Cut the anion exchange membrane (or the original membrane for the introduction of the anion exchange group with the above-mentioned highly crosslinked resin layer) into 2×2 cm, immerse it in a 1 mol/L hydrochloric acid aqueous solution, and set counter ion Cl ^{-. After fully washing the Cl-} type anion exchange membrane with ultrapure water, immerse it in a 1 mol/L sodium nitrate aqueous solution to ^{release Cl-} into the liquid. The anion exchange membrane was removed from the 1 mol / L aqueous solution of sodium nitrate, the by potentiometric titration apparatus was titrated with 0.1 mol / L of aqueous solution of silver nitrate according to the following formula: Cl ^- chloro not generated ⁺ Ag + → AgCl obtained The titration of silver. On the other hand, the anion immersed in 1 mol / L aqueous solution of sodium nitrate exchange membrane was immersed again in 1 mol / L of aqueous hydrochloric acid, the counterion to Cl ^-, after sufficiently washed with ultrapure water, by The film is fully dried by a vacuum dryer. Measure the weight of the anion exchange membrane after drying.

Using the obtained result, according to the following formula: Anion exchange capacity (meq/g-dry membrane) = titration (mL)×0.1 (mol/L)/dry membrane weight (g-dry membrane) Determine the anion exchange capacity.

<Example 1> To 100 parts by weight of a polymerizable composition including 35 parts by weight of chloromethylstyrene, 40 parts by weight of styrene, and 10 parts by weight of divinylbenzene, di-tertiary butyl peroxide is added as a radical polymerization initiator 5 parts by weight and 10 parts by weight of a styrene-butadiene copolymer as a matrix resin to obtain a paste-like polymerizable composition.

Next, the above polymerizable composition was coated on a high-density polyethylene woven fabric (trade name: NIPPU strong net 200 mesh, wire diameter 86 μm, mesh number per inch is 156 (longitudinal)/100 (horizontal) Root, manufactured by NBC Industries), both sides are covered with a release film containing polyester film, and then polymerized by the slurry method. The polymerization method was to raise the temperature from 20°C to 100°C in 2 hours, then to 120°C in 30 minutes, and maintain at 120°C for 6 hours to obtain the original membrane for the introduction of anion exchange groups.

Next, peel off the peeling film from the original film for the introduction of anion exchange groups. At this time, the peeling film on both sides of the original film is not completely peeled off, and the peeling film is still attached to one side. The original film for introducing anion exchange groups covered with a release film on one side was immersed in a 0.05N-dimethylamine aqueous solution at 30°C for 8 hours to form a proton permeation suppression layer (highly crosslinked resin layer) on the other surface. At this stage, the anion exchange capacity of the anion exchange membrane was measured, and the result was 0.03 meq/g-dry membrane. Before the treatment of converting a chloromethyl group into a quaternary ammonium group described later, the membrane has the above-mentioned anion exchange capacity, so it can be confirmed that the anion exchange capacity of the highly crosslinked resin layer in the membrane is the above-mentioned value.

Secondly, remove the polyester film covering one side. Using an aqueous solution containing 10% by mass of trimethylamine and 20% by mass of acetone, it was subjected to a quaternization reaction at 30°C for 16 hours to convert the remaining chloromethyl groups in the film into quaternary ammonium groups. The anion exchange capacity of the obtained anion exchange membrane was measured, and the result was 1.37 meq/g-dry membrane. From this result, it was confirmed that the anion exchange capacity of the above-mentioned highly crosslinked resin layer was 0.02 times the ratio of the anion exchange capacity of the entire anion exchange membrane. The thickness of the anion exchange membrane is 190 μm.

Next, the obtained anion exchange membrane and Nafion N324 manufactured by DuPont as a cation exchange membrane were assembled into an electrolysis device with ^{an effective membrane area of 1 dm 2 arranged in the manner shown in FIG. 1.} The anion exchange membrane is arranged so that the surface on which the highly crosslinked resin layer is formed faces the cathode side. Furthermore, the anode uses platinum plated titanium plate, and the cathode uses SUS316.

Circulate 0.5 equivalent of sulfuric acid in the anode chamber of the above electrolysis device, and circulate 2.5 equivalent of tetramethylammonium chloride aqueous solution between the anion exchange membrane and the cation exchange membrane on the cathode side, and make the quaternary ammonium hydroxide aqueous solution in the cathode chamber In the cycle, electrolysis was continuously performed while maintaining the current density at 30 A/dm ² and the temperature at 40°C. During continuous operation, the concentration of tetramethylammonium hydroxide in the cathode compartment was made 2.0 equivalents. Add pure water when the concentration becomes high, and add this component when it becomes low, so that the concentration of the liquid circulating in the same chamber becomes fixed.

Perform continuous operation for 3 months to evaluate the initial (first day) voltage value and the current efficiency of the anion exchange membrane at the beginning, after 1 month, 2 months, and 3 months. The results are shown in Table 1.

<Example 2> In Example 1, the original membrane for the introduction of anion exchange groups was immersed in a 0.05N-dimethylamine aqueous solution for 3 hours, except that it was carried out in the same manner as in Example 1. The membrane produced on one side was formed with proton permeation The anion exchange membrane of the suppression layer (highly cross-linked resin layer).

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.01 meq/g-dry membrane. In addition, the anion exchange capacity of the anion exchange membrane as a whole is 1.39 meq/g-dry membrane. From this result, it was confirmed that the anion exchange capacity of the highly crosslinked resin layer was 0.007 times the anion exchange capacity of the entire anion exchange membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

<Example 3> In Example 1, the original membrane for the introduction of anion exchange groups was immersed in a 0.05N-dimethylamine aqueous solution for 40 hours, except that it was carried out in the same manner as in Example 1. The surface of the membrane produced on one side was formed with protons permeating The anion exchange membrane of the suppression layer (highly cross-linked resin layer).

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.20 meq/g-dry membrane. In addition, the anion exchange capacity of the anion exchange membrane as a whole is 1.2 meq/g-dry membrane. From this result, it was confirmed that the anion exchange capacity of the highly crosslinked resin layer was 0.17 times the ratio of the anion exchange capacity of the entire anion exchange membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

<Example 4> In Example 1, the original membrane for introducing anion exchange groups was immersed in a 0.05N-dimethylamine aqueous solution in a state where the peeling films on both sides were peeled off, and it was carried out in the same manner as in Example 1, except that the original membrane was immersed in a 0.05N-dimethylamine aqueous solution. An anion exchange membrane with proton permeation suppression layers (highly cross-linked resin layers) formed on both sides of the membrane.

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.03 meq/g per single side-dry membrane. In addition, the anion exchange capacity of the anion exchange membrane as a whole is 1.34 meq/g-dry membrane. From this result, it was confirmed that the anion exchange capacity per one side of the highly crosslinked resin layer was 0.02 times the anion exchange capacity of the entire anion exchange membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

<Example 5> In Example 1, the original membrane for the introduction of anion exchange groups was immersed in a 0.05N-dimethylamine aqueous solution for 2 hours, except that it was carried out in the same manner as in Example 1. The membrane surface produced on one side was formed with protons permeating The anion exchange membrane of the suppression layer (highly cross-linked resin layer).

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.006 meq/g-dry membrane. In addition, the anion exchange capacity of the anion exchange membrane as a whole is 1.394 meq/g-dry membrane. From this result, it can be confirmed that the anion exchange capacity of the highly crosslinked resin layer is 0.004 times the ratio of the anion exchange capacity of the entire anion exchange membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

<Example 6> In Example 1, the original membrane for the introduction of anion exchange groups was immersed in a 0.05N-dimethylamine aqueous solution for 60 hours, except that it was carried out in the same manner as in Example 1. The membrane produced on one side was formed with proton permeation The anion exchange membrane of the suppression layer (highly cross-linked resin layer).

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.3 meq/g-dry membrane. In addition, the anion exchange capacity of the entire anion exchange membrane is 1.1 meq/g-dry membrane. From this result, it was confirmed that the anion exchange capacity of the highly crosslinked resin layer was 0.27 times the ratio of the anion exchange capacity of the entire anion exchange membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

<Example 7> In Example 1, the original membrane for the introduction of anion exchange groups was immersed in a 0.05N-diethylamine aqueous solution for 10 hours, except that it was carried out in the same manner as in Example 1. The membrane surface produced on one side was formed with protons permeating The anion exchange membrane of the suppression layer (highly cross-linked resin layer).

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.03 meq/g-dry membrane. In addition, the anion exchange capacity of the entire anion exchange membrane was 1.37 meq/g-dry membrane, which was the same as in Example 1. From this result, it was confirmed that the anion exchange capacity of the above-mentioned highly crosslinked resin layer was 0.02 times the ratio of the anion exchange capacity of the entire anion exchange membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

<Example 8> In Example 1, the original membrane for the introduction of anion exchange groups was immersed in a 0.05N-tetramethylethylenediamine aqueous solution for 15 hours, except that it was carried out in the same manner as in Example 1, and the membrane surface was formed on one side. Anion exchange membrane with proton permeation suppression layer (highly cross-linked resin layer).

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.06 meq/g-dry membrane. In addition, the anion exchange capacity of the entire anion exchange membrane is 1.4 meq/g-dry membrane. From this result, it can be confirmed that the anion exchange capacity of the highly crosslinked resin layer is 0.04 times the ratio of the anion exchange capacity of the entire anion exchange membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

<Example 9> To 100 parts by weight of a polymerizable composition containing 35 parts by weight of chloromethylstyrene, 40 parts by weight of styrene, and 10 parts by weight of divinylbenzene, di-tertiary butyl peroxide is added as a radical polymerization initiator 5 parts by weight to obtain a paste-like polymerizable composition.

Next, the above-mentioned polymerizable composition was applied to a polyethylene biaxially stretched porous film (thickness 135 μm, porosity 49%, average pore diameter 0.13 μm), and the two sides of the polyethylene film were peeled off. After the film is coated, polymerization is carried out by the slurry method. The polymerization method was to raise the temperature from 20°C to 100°C in 2 hours, then to 120°C in 30 minutes, and maintain at 120°C for 6 hours to obtain the original membrane for the introduction of anion exchange groups.

Next, peel off the peeling film from the original film for the introduction of anion exchange groups. At this time, the peeling film on both sides of the original film is not completely peeled off, and the peeling film is still attached to one side. The original film for introducing anion exchange groups covered with a release film on one side was immersed in a 0.05N-dimethylamine aqueous solution at 30°C for 12 hours to form a proton permeation suppression layer (highly crosslinked resin layer) on the other surface.

Secondly, remove the polyester film covering one side. Using an aqueous solution containing 10% by mass of trimethylamine and 20% by mass of acetone, it was subjected to a quaternization reaction at 30°C for 16 hours to obtain an anion exchange membrane.

In this anion exchange membrane, the anion exchange capacity of the highly crosslinked resin layer is 0.03 meq/g-dry membrane. In addition, the anion exchange capacity of the anion exchange membrane as a whole is 1.67 meq/g-dry membrane. From this result, it was confirmed that the anion exchange capacity of the highly crosslinked resin layer was 0.018 times the ratio of the anion exchange capacity of the entire anion exchange membrane. The thickness of the anion exchange membrane is 160 μm.

Using this anion exchange membrane, production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1.

＜Comparative example 1＞ In Example 1, the original membrane for introducing anion exchange groups was not immersed in a 0.05N-dimethylamine aqueous solution, except that it was carried out in the same manner as in Example 1, and no proton permeation suppression was formed on the surface of any membrane. Layer (highly cross-linked resin layer) anion exchange membrane.

The anion exchange capacity of the anion exchange membrane as a whole is 1.4 meq/g-dry membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1. In addition, the current efficiency dropped too much before reaching 3 months and the liquid balance could not be maintained, so the electrolysis was stopped.

＜Comparative example 2＞ In Example 1, for the electrolytic device of FIG. 1, the obtained anion exchange membrane with a proton permeation suppression layer (highly crosslinked resin layer) formed on one side of the membrane surface was formed with the highly crosslinked resin layer Except for disposing the surface facing the anode side, the same procedure as in Example 1 was carried out to manufacture tetramethylammonium hydroxide. In this production, the voltage value and the current efficiency of the anion exchange membrane were measured, and the results are shown in Table 1.

<Comparative Example 3> In Example 9, the original membrane for introducing anion exchange groups was not immersed in a 0.05N-dimethylamine aqueous solution, except that it was carried out in the same manner as in Example 9, and no proton permeation suppression was formed on the surface of any membrane. Layer (highly cross-linked resin layer) anion exchange membrane.

The anion exchange capacity of the anion exchange membrane as a whole is 1.7 meq/g-dry membrane. Furthermore, using this anion exchange membrane, the production of tetramethylammonium hydroxide was carried out in the same manner as in Example 1, and the voltage value and the current efficiency of the anion exchange membrane were measured. The results are shown in Table 1. In addition, the current efficiency dropped too much before reaching 3 months and the liquid balance could not be maintained, so the electrolysis was stopped.

[Table 1] High void substrate for anion exchange membrane Configuration of proton penetration suppression layer Amine compound for forming proton permeation suppression layer Processing time Anion exchange capacity of proton permeation suppression layer The ratio of the proton permeation suppression layer to the anion exchange capacity of the whole membrane Current efficiency Voltage hour meq/g-dry film Times % V initial 1 month later 2 months later 3 months later initial Example 1 Weaving Cathode side Dimethylamine 8 0.03 0.02 85 84 83 79 11 Example 2 3 0.01 0.007 83 82 81 77 10 Example 3 40 0.2 0.17 89 88 87 83 17 Example 4 Two sides 8 0.03 (per side) 0.02 (per side) 86 86 85 84 12 Example 5 Cathode side 2 0.006 0.004 82 81 79 75 10 Example 6 60 0.3 0.27 90 89 88 85 twenty two Example 7 Diethylamine 10 0.03 0.02 85 84 83 80 14 Example 8 Tetramethylhexamethylenediamine 15 0.06 0.04 84 82 81 76 12 Example 9 Porous membrane Dimethylamine 12 0.03 0.018 87 86 85 81 9 Comparative example 1 Weaving no - - - - 81 77 70 - 9 Comparative example 2 Anode side Dimethylamine 8 0.03 0.02 85 83 78 72 10 Comparative example 3 Porous membrane no - - - - 80 77 71 - 7

1: anode 2: cathode 3: power supply 4: anode chamber 5: Raw material room 6: Cathode chamber 7: Acid Room 9: Protons pass through the inhibitory layer 10: base layer A: Anion exchange membrane C1: Cation exchange membrane C2: Cation exchange membrane

Fig. 1 is a schematic explanatory diagram showing the principle of electrolysis of the production method of quaternary ammonium hydroxide according to the present invention. Fig. 2 is a schematic explanatory diagram showing another aspect of electrolysis of the principle of the method for producing quaternary ammonium hydroxide of the present invention. Fig. 3 is a schematic explanatory diagram showing the principle of the method for producing quaternary ammonium hydroxide of the present invention and other aspects of electrolysis.

Claims (7)

A method for producing quaternary ammonium hydroxide, in which an anion exchange membrane and a cation exchange membrane are arranged between the electrodes in an electrolytic cell, and an aqueous solution of quaternary ammonium halide is supplied to a compartment separated by the anion exchange membrane and the cation exchange membrane. A method of electrolysis to produce quaternary ammonium hydroxide; The manufacturing method is characterized in that: a membrane with a proton permeation suppression layer formed on the surface of the membrane on one side is arranged so that the surface on which the proton permeation suppression layer is formed faces the cathode side, and the film is used as The above-mentioned anion exchange membrane performs electrolysis. The method for producing quaternary ammonium hydroxide according to claim 1, wherein the proton permeation suppression layer has an anion exchange capacity of 0.005 to 0.5 meq/g-dry membrane, and the anion exchange capacity is relative to the anion exchange capacity of the whole anion exchange membrane The ratio is 0.002 to 0.3 times. The method for producing quaternary ammonium hydroxide according to claim 1 or 2, wherein the proton permeation suppression layer is formed of a highly cross-linked resin layer. The method for producing quaternary ammonium hydroxide according to any one of claims 1 to 3, wherein a proton permeation suppression layer is also provided on the surface of the membrane on the other side facing the cathode side. The method for producing quaternary ammonium hydroxide according to any one of claims 1 to 4, wherein the anion exchange membrane is produced as follows: for making an aromatic polymerizable monomer having a halogenated alkyl group and a crosslinkable polymerizable monomer The original membrane for the introduction of anion exchange groups obtained by the polymerization of the polymerizable composition, the dialkylamine compound or polyamine compound is brought into contact with the membrane surface on one side, and a highly crosslinked resin with a higher crosslinking ratio than the inside is formed on the membrane surface After that, the trialkylamine is contacted with the remaining haloalkyl group in the film to convert it into a quaternary ammonium group. A device for producing quaternary ammonium hydroxide, which disposes an anion exchange membrane and a cation exchange membrane between the electrodes, and supplies an aqueous solution of quaternary ammonium halide to a chamber separated by the anion exchange membrane and the cation exchange membrane for electrolysis, thereby manufacturing Equipment for quaternary ammonium hydroxide; The manufacturing device is characterized in that the anion exchange membrane is provided with a proton permeation suppression layer on the cathode side surface. Such as the quaternary ammonium hydroxide manufacturing device of claim 6, wherein the anion exchange membrane also has a proton permeation suppression layer on the anode side surface.

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