JPH11106975A - Method for producing quaternary ammonium hydroxide - Google Patents

Abstract

[PROBLEMS] To develop a method for stably producing a quaternary ammonium hydroxide aqueous solution for a long period of time. In one embodiment, between an anode and a cathode, 1
One or more cation exchange membranes, one or more anion exchange membranes,
By disposing one or more cation exchange membranes, an anode chamber in which an anode is present, an acid chamber in which the anode side is partitioned by a cation exchange membrane and the cathode side is partitioned by an anion exchange membrane, and the anode side is an anion exchange membrane A raw material chamber partitioned by a cation exchange membrane on the cathode side, a cathode chamber in which a cathode exists, and two or more cation exchange membranes or anion exchange membranes when the same kind of ion exchange membranes are used. Production of a quaternary ammonium hydroxide in which a quaternary ammonium halide aqueous solution is supplied to a raw material chamber and electrolysis is performed using an electrolytic cell having a prepared intermediate chamber, and quaternary ammonium hydroxide is generated in a cathode chamber. In the method, one or more chamber liquids of an anode chamber, an acid chamber, and an intermediate chamber located between the anode chamber and the acid chamber are circulated and supplied while performing a treatment for removing free halogens such as aeration treatment. Let Quaternary method for producing ammonium hydroxide, characterized in that.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing quaternary ammonium hydroxide, and more particularly, to a method for electrolyzing a quaternary ammonium salt through an ion exchange membrane to obtain a high-purity quaternary ammonium hydroxide.
The present invention relates to a method for stably producing an aqueous solution of quaternary ammonium.

[0002]

2. Description of the Related Art Quaternary ammonium hydroxide is useful as a phase transfer catalyst, a standard solution of a base in nonaqueous solvent titration, and a strong organic base such as an organic alkaline agent. It is also used for cleaning and etching semiconductor substrates in the manufacture of LSIs, and as a developer for positive resist.

Heretofore, for producing quaternary ammonium hydroxide, there is known a method of electrolyzing a quaternary ammonium halide as a raw material through an ion exchange membrane. Of which
A cation exchange membrane, an anion exchange membrane, and a cation exchange membrane are arranged between a cathode and an anode in this order from the anode side as described in JP-A-1-108388, and an anode chamber in which the anode exists. There are an acid chamber separated on the anode side by a cation exchange membrane and a cathode side separated by an anion exchange membrane, a raw material chamber separated on the anode side by an anion exchange membrane and separated on the cathode side by a cation exchange membrane, and a cathode. A method for performing electrolysis by using an electrolytic cell in which a cathode chamber is formed and supplying a quaternary ammonium halide aqueous solution to the raw material chamber is a method for producing high purity quaternary ammonium hydroxide.
Grade ammonium can be obtained as an aqueous solution, and the anion exchange membrane can be used without deterioration if operated for a certain period of time.

That is, in the above method, the quaternary ammonium halide supplied to the raw material chamber is decomposed into quaternary ammonium ions and anions constituting a salt, and each of the quaternary ammonium ions and the cation exchange membrane is anion exchange membrane. As a result,
Quaternary ammonium hydroxide is generated in the cathode chamber of the electrolytic cell, and acid is generated in the acid chamber.

[0005]

In the above-mentioned method for producing quaternary ammonium hydroxide by electrolysis,
Although the chamber is partitioned from the adjacent acid chamber by the cation exchange membrane into the anode chamber, halide ions permeate from the acid chamber. The permeated halide ions are oxidized in the anode chamber to become halogens and free halogens of hypohalous acids, and are dissolved in the anode chamber liquid. Then, a part of the dissolved free halogens permeate the cation exchange membrane again and enter the acid chamber. Thus, free halogens are strongly oxidizing substances, while
Anion exchange membranes generally have a property of being easily degraded by such oxidizing substances. Therefore, even in such a manufacturing method,
When the chamber liquid is supplied by the circulation method, the concentration of free halogens in the acid chamber increases, and the problem that the anion exchange membrane gradually deteriorates when the operation is performed for a long time occurs.

When the anion exchange membrane deteriorates in this way, the amount of cations permeating through the cation exchange membrane on the cathode side and the amount of anions permeating through the anion exchange membrane cannot be balanced, resulting in abnormal operation. Come. Therefore, it has been desired to develop a method for stably producing a quaternary ammonium hydroxide aqueous solution over a long period of time.

[0007]

Means for Solving the Problems In view of the above-mentioned problems, the present inventors have continued intensive studies. As a result, in the production of a quaternary ammonium hydroxide aqueous solution, by performing a treatment for removing free halogens on the chamber liquid in the anode chamber or acid chamber,
The inventors have found that the above problems can be solved, and have completed the present invention.

That is, according to the present invention, at least one cation exchange membrane is provided between an anode and a cathode in order from the anode side.
By arranging at least one or more anion exchange membranes and at least one or more cation exchange membranes, the anode chamber where the anode exists, the anode side is partitioned by the cation exchange membrane, and the cathode side is partitioned by the anion exchange membrane. Acid chamber, a raw material chamber in which the anode side is partitioned by an anion exchange membrane and the cathode side is partitioned by a cation exchange membrane, a cathode chamber in which a cathode is present, and two positive electrodes in the case where a plurality of the same type ion exchange membranes are used. Using an electrolytic cell having an intermediate chamber separated by an ion exchange membrane or an anion exchange membrane, a quaternary ammonium halide aqueous solution is supplied to the raw material chamber to perform electrolysis, and a quaternary ammonium hydroxide is supplied to the cathode chamber. In the method for producing a quaternary ammonium hydroxide for producing the above, the intermediate chamber in the case of using an anode chamber, an acid chamber, and a plurality of cation exchange membranes between the anode chamber and the acid chamber At least room of chamber fluid selected et a method for producing a quaternary ammonium hydroxide, characterized in that circulating supplies while subjected to removal treatment of the free halogens.

In the electrolytic cell used in the production method of the present invention, the case where there is no intermediate chamber is provided between an anode 1 and a cathode 2 in order from the anode side as illustrated in the schematic diagram of FIG.
The cation exchange membrane 3, the anion exchange membrane 4, and the cation exchange membrane 5 are provided. In the electrolytic cell, a chamber partitioned by an anion exchange membrane 4 on the anode side and a cathode exchange membrane 5 on the cathode side becomes a raw material chamber 8 for supplying a quaternary ammonium halide aqueous solution, and a cathode chamber in which the cathode 2 exists. 9 is a chamber for producing quaternary ammonium hydroxide.

[0010] A chamber partitioned on the anode side by the cation exchange membrane 3 and on the cathode side by the anion exchange membrane 4 is an acid chamber 7 in which an acid is generated. Thus, by forming an acid chamber between the raw material chamber and the anode chamber, it becomes possible to prevent free halogens dissolved in the anolyte from directly contacting the anion exchange membrane 4. .

In the above electrolytic cell, a quaternary ammonium hydroxide aqueous solution is contained in the cathode chamber 9, a quaternary ammonium halide aqueous solution is contained in the raw material chamber 8, and a quaternary ammonium halide solution is contained in the acid chamber 7. An aqueous solution of an acid composed of anions and hydrogen ions (hereinafter sometimes referred to as an acid chamber solution) constituting an acid solution is provided in the anode chamber 6 with an aqueous solution of an acid such as sulfuric acid, nitric acid, and hydrochloric acid (hereinafter referred to as an anolyte). May be supplied).

In the electrolytic cell used in the present invention, one or more cation exchange membranes are further provided between the anode and the cation exchange membrane constituting the acid chamber, in addition to the above basic chamber configuration. One or more anion exchange membranes may be further provided between the cation exchange membrane constituting the acid chamber and the anion exchange membrane constituting the raw material chamber, or the cation exchange membrane and the cathode constituting the raw material chamber may be provided. Each intermediate chamber may be formed by further providing one or more cation exchange membranes between them. In this case, these intermediate chambers are adjacent to each other because the quaternary ammonium halide in the raw material chamber liquid and the free halogens in the cathode chamber liquid diffuse through the respective ion exchange membranes from the raw material chamber and the cathode chamber. It has the function of preventing transmission to the room. Further, in such an embodiment, an acid aqueous solution is supplied to an intermediate chamber formed between the anode chamber and the acid chamber, and an acidic aqueous solution is supplied to an intermediate chamber formed between the acid chamber and the raw material chamber, A quaternary ammonium hydroxide aqueous solution is supplied to an intermediate chamber formed between the raw material chamber and the cathode chamber.

In the present invention, the quaternary ammonium halide supplied as a raw material has a general formula [R ₄ N] X, wherein R is an alkyl group generally having 1 to 4 carbon atoms,
X represents a hydroxyalkyl group or an aryl group, and X represents a halogen selected from fluorine, chlorine, bromine, and iodine.
Is an organic salt represented by Specifically, for example, tetramethylammonium fluoride, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium fluoride,
Tetraalkylammonium halides such as tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetraphenylammonium fluoride , Tetraphenylammonium chloride, tetraphenylammonium bromide, tetraphenylammonium iodide and the like, tetraarylammonium halides, tetrahydroxymethylammonium fluoride, tetrahydroxymethylammonium chloride, tetrahydroxymethylammonium bromide, tetrahydroxy iodide Methyl ammonium, tetrahydroxyethyl ammonium fluoride, tetrahydroxyethyl ammonium chloride Monium, tetrahydroxyethylammonium bromide, tetrahydroxyethylammonium iodide, etc., halogenated tetrahydroxyalkylammoniums, or halogenated alkyl / arylammoniums, such as trialkyl / arylammonium halides, and trihydroxyalkyl halides. Hydroxyalkyl halides such as aryl ammoniums, aryl ammoniums, trialkyl halides, etc.
Alkyl hydroxyalkyl ammonium halides such as hydroxyalkyl ammoniums are generally mentioned. Of these, tetraalkylammonium halides are generally and preferably used. Specifically, it is particularly preferable to use tetramethylammonium chloride and tetraethylammonium chloride.

The concentration of the quaternary ammonium halide aqueous solution supplied to the raw material chamber of the electrolytic cell is 1 to 4 kmo.
1 / m ³ is common. The quaternary ammonium hydroxide obtained in the present invention includes a compound represented by the general formula [R ₄ N] OH
(Wherein, R is the same as above), and is an organic compound corresponding to the above-mentioned quaternary ammonium halide as a raw material, for example, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like. The concentration of the aqueous solution of quaternary ammonium hydroxide supplied to the cathode compartment of the electrolytic cell is generally 1 to ³ kmol / m3.

The acid chamber liquid used in the present invention has the general formula HX
(Wherein, X is the same as above), specifically, an aqueous solution of hydrogen halide such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, and oxalic acid. The concentration of the aqueous acid solution supplied to the acid chamber of the electrolytic cell is 0.1 to 1 kmol /
m ³ is common.

The anolyte used in the present invention is an aqueous solution of an acid such as sulfuric acid or nitric acid. Hydrochloric acid is not preferred because the generation of free chlorine becomes severe. The concentration of the aqueous acid solution supplied to the anode chamber of the electrolytic cell is 0.1 to 1 kmol / m ^3.
Is common.

In the above-mentioned electrolytic cell, the chamber liquid is forcibly or spontaneously discharged from each chamber, and the discharged chamber liquid is controlled so that the concentration of each aqueous solution is within the above-mentioned preferred range. However, it is preferable to circulate and supply at least a part thereof to the original chamber again from the viewpoint of maintaining stable operation. In particular, in the present invention, it is essential that at least one chamber liquid selected from the anode chamber, the acid chamber, and the intermediate chamber located between the anode chamber and the acid chamber be circulated and supplied as described later. Here, the circulation supply may be all or part of the discharged room liquid.

The cation exchange membrane 3 used in the electrolytic cell is
Conventionally known ones are used without any limitation, for example, cations having a sulfonic acid group, a carboxylic acid group, a phosphoric acid group or the like as an ion exchange group, and a base such as a hydrocarbon-based, fluorocarbon-based, or perfluorocarbon-based resin. An exchange membrane is used.

On the other hand, as the anion exchange membrane 4, a conventionally known one can be used without any limitation. For example, not only an anion exchange membrane having a strongly basic group such as a quaternary ammonium base, a phosphonium base, or a sulfonium base but also an anion exchange membrane can be used. , First grade, second grade
It is also effective for anion exchange membranes having weakly basic groups such as primary and tertiary amino groups.

The electrolysis is preferably carried out at a current density of 0.1 to 50 kA / m ² and a temperature of each chamber liquid of 20 to 60 ° C.

In the production of quaternary ammonium hydroxide using the electrolytic cell having the above structure, free halogens are generated in the anode chamber 9 and dissolved in the anolyte as described above. Then, the transfer of the free halogens to the acid chamber is blocked by the cation exchange membrane 5, but the permeation of the free halogens permeates the cation exchange membrane 5 by diffusion. Further, when an intermediate chamber is provided between the anode chamber 6 and the acid chamber 7, the invasion of the free halogens into the acid chamber is further suppressed, but the permeation gradually proceeds. Therefore, the anode compartment, acid compartment,
When the operation is performed while circulating and supplying at least one chamber liquid selected from the intermediate chamber located between the anode chamber and the acid chamber, the concentration of free halogens in the acid chamber increases, and the operation is performed for a long time. Then, the anion exchange membrane 4 is deteriorated.

On the other hand, according to the present invention, in the method for producing quaternary ammonium hydroxide, in order to prevent the anion exchange membrane from deteriorating due to free halogens, the anode chamber, the acid chamber, The most characteristic feature is that at least one chamber liquid selected from the intermediate chamber located between the anode chamber and the acid chamber is subjected to the removal treatment of the free halogens. In particular, in the chamber liquid of the acid chamber supplied by circulation,
It is effective to remove the free halogens. As a result, the amount of free halogens in contact with the anion exchange membrane is greatly reduced. As a result, in the present invention, it is possible to stably produce quaternary ammonium hydroxide for a long time without deteriorating the anion exchange membrane.

In the present invention, free halogens include halogens such as fluorine, chlorine, bromine and iodine, and halogens such as hypofluorite, hypochlorous acid, hypobromite and hypoiodite. Refers to hypohalous acids. In the present invention, it is preferable to perform the above-described free halogen removal treatment so that the concentration of these free halogens in the acid chamber is maintained at 10 ppm or less, preferably 1 ppm or less, and more preferably 0.5 ppm or less.

The removal treatment of free halogens from the circulated and supplied room liquid may be carried out in the chamber of the electrolytic cell if possible, but is generally performed in the middle of the circulated supply path of the room liquid. You. For example, as shown in FIG. 1, it is preferable to provide a storage tank 11 in the middle of the circulation supply path, and to carry out the storage tank 11 therein.

The specific method of removing the oxidizing substance is not particularly limited, and may be carried out by any known method. Preferable examples include aeration treatment, blending of a reducing substance into a liquid, and contact with an adsorbent.

For the aeration treatment, a well-known method for bringing the treatment liquid into contact with a gas that does not react with the treatment liquid and removing substances dissolved in the treatment liquid can be appropriately employed. Preferably, a method in which the gas is bubbled in a storage tank provided in the middle of the circulation supply path, a method in which the gas is sprayed on the liquid surface, and the like are exemplified.

As the gas, any gas can be used as long as it does not react with water and acid and does not adversely affect the cation exchange membrane and the anion exchange membrane. For example, nitrogen, oxygen, air, helium, neon, argon, xenon and the like can be mentioned. At this time, the gas is usually 0.01 m ³
It is preferable to continuously or intermittently aerate at a supply rate of 0.0001 to 50 Nm ³ per hour. In this range, the aeration effect is sufficiently exhibited, and the operation can be performed without excessively increasing the size of the gas supply device and the waste gas treatment device. From the viewpoint of good effects and economy, the supply amount of this gas is preferably 0.01 to 10 Nm ^{3 /} h. Usually, the liquid temperature at the time of performing the aeration treatment is preferably from 0 to 80 ° C. If the temperature of the aeration treatment is lower than 0 ° C, the efficiency of removing free halogens by the aeration treatment tends to decrease, and if it is higher than 80 ° C, stable operation of the electrolytic cell tends to be difficult. 20-60 ° C which is a suitable temperature for electrolysis
Is more preferred. The pressure may be any of normal pressure, increased pressure, and reduced pressure, but it is economically preferable to perform the same pressure as in the electrolysis.

Further, in the present invention, the compounding treatment of the reducing substance is performed in a pipe or a storage tank in the middle of the circulation supply path.
It is preferred to carry out by incorporating the substance into the circulating fluid. As the reducing substance to be used, a general reducing agent can be employed without any limitation. For example, sodium thiosulfate,
Low oxygen salts such as potassium thiosulfate, ammonium sulfite, potassium sulfite, ammonium phosphite, ammonium hydrogen phosphite, sodium phosphite, sodium hydrogen phosphite, aldehydes such as formic acid, formaldehyde and acetaldehyde, and hydroxylamine And olefins such as ethylene and propylene, and hydroquinones such as hydroquinone and substituted hydroquinone. Preferred are those containing no metal ion, and aldehydes such as formic acid, formaldehyde and acetaldehyde, hydroxylamines and hydrazines, olefins such as ethylene and propylene, and hydroquinones such as hydroquinone and substituted hydroquinone are particularly preferred.

The molar ratio of the reducing substance to the dissolved free halogen is preferably 0.01 to 1000 times, and it is economical and preferable. In order to carry out the present invention more efficiently, the compounding amount is preferably 0.1 to 100 times the molar ratio of free halogens. Such a reducing substance may be diluted with water and blended. When the reducing substance is a gas, a method of blending by aeration is also effective. The temperature at the time of addition is not particularly limited, but is preferably adjusted to the operating temperature of the electrolytic cell in view of energy costs.

Further, in the present invention, the contact treatment with the adsorbent is carried out by bringing the adsorbent into contact with the circulating liquid in the middle of the circulation supply path. As a method for bringing the adsorbent into contact with the liquid, a general solid-liquid contact method can be employed without limitation. Examples include the fixed bed method and the fluidized bed method. As the adsorbent, an adsorbent having acid resistance can be employed without limitation.
For example, activated carbon, molecular sieves, clay minerals and the like can be mentioned. The amount of adsorbent used depends on the equilibrium adsorption amount of the adsorbent to be used, so it cannot be specified unconditionally.However, it is necessary to use an amount such that the adsorbed amount of free halogens does not exceed the equilibrium adsorption amount of the adsorbent. General.

[0031]

According to the present invention, in the production of quaternary ammonium hydroxide by electrolysis, deterioration of the anion exchange membrane can be largely prevented. As a result, quaternary ammonium hydroxide can be stably produced for a long period of time.

[0032]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Example 1 A cation exchange membrane (manufactured by DuPont, trade name: Nafion 324) and an anion exchange membrane (manufactured by Tokuyama Corporation) were arranged between an anode formed by plating platinum on a titanium plate and a cathode formed of SUS316 in order from the anode. And a cation exchange membrane (manufactured by DuPont, trade name: Nafion 901) to form an electrolytic cell having an effective energizing area of 0.01 m ² comprising four chambers.

Using the above electrolytic cell, 0.3 km
ol / m ³ of sulfuric acid, 0.3 Kmol / m ³ of hydrochloric acid in the acid chamber, 2.5 Kmol / m ³ of tetramethylammonium chloride aqueous solution in the raw material chamber, and 2.3 Kmol / m ³ of hydroxide in the cathode chamber. A tetramethylammonium aqueous solution was supplied, and the discharged liquid was circulated and supplied again to each chamber while adjusting the concentration. In this electrolytic cell, electrolysis was continuously performed at a current density of 1.8 KA / m ² .

At this time, a polypropylene tank having a volume of 0.01 m ³ is provided in the circulation path of the chamber liquid (hydrochloric acid) circulating in the acid chamber, and the hydrochloric acid constantly circulating in this tank is 0.005 m ^3.
I decided to stay. Then, nitrogen gas was bubbled into the liquid stored in the tank at a flow rate of 0.06 Nm ^{3 /} hour. The liquid in each chamber was circulated at a flow rate of 0.15 m ³ / H.

Meanwhile, the sulfuric acid in the anode chamber and the hydrochloric acid in the acid chamber were sampled with time, neutralized, and then subjected to JIS K
The amount of dissolved chlorine and free chlorine composed of hypochlorous acid was measured by the residual chlorine determination method described in 0101-1. The current efficiency of the anion exchange membrane was also measured.

One week after the start of operation, 2000 ppm of free chlorine was observed in sulfuric acid in the anode compartment, but only 0.1 ppm of free chlorine was observed in hydrochloric acid in the acid compartment.
The current efficiency of the anion exchange membrane was 80%. Thereafter, during a continuous operating period of 9 months, 2000 ppm of free chlorine was observed in sulfuric acid in the anode compartment, but only 0.1 ppm of free chlorine in hydrochloric acid in the acid compartment was observed. The current efficiency of the anion exchange membrane was maintained at 80%.

Comparative Example 1 The same operation as in Example 1 was performed except that bubbling with nitrogen gas was not performed on the circulating supply liquid in the acid chamber.

One week after the start of the operation, 2000 ppm of free chlorine in sulfuric acid in the anode chamber and about 20 ppm of free chlorine in hydrochloric acid in the acid chamber were observed. The current efficiency of the anion exchange membrane was 80%. Thereafter, during a continuous operation period of 9 months, about 20 ppm of free chlorine was observed in the hydrochloric acid in the acid chamber. Nine months after the start of operation, the current efficiency of the anion exchange membrane dropped to 70%.

Example 2 In Example 1, instead of providing a polypropylene tank having a volume of 0.01 m ^{3 in} the circulation path of hydrochloric acid circulating in the acid chamber, a volume of 0.01 mm was supplied to the circulation line of sulfuric acid circulating in the anode chamber.
except the provision of the polypropylene tank m ^3, was subjected to the same procedure as in Example 1.

As a result, one week after the start of the operation, 20 ppm of free chlorine in sulfuric acid in the anode compartment was observed, but only 0.2 ppm of free chlorine in hydrochloric acid in the acid compartment was observed.

The current efficiency of the anion exchange membrane is 80%.
Met. During the continuous operating period of 9 months, 20 ppm of free chlorine was still observed in sulfuric acid in the anode compartment, but only 0.2 ppm of free chlorine in hydrochloric acid in the acid compartment was observed thereafter. The current efficiency of the anion exchange membrane was maintained at 80%.

Example 3 The same operation as in Example 1 was performed, except that bubbling with nitrogen gas was performed at a flow rate of 1 Nm ^{3 /} hour.

As a result, one week after the start of the operation, 2000 ppm of free chlorine was observed in sulfuric acid in the anode compartment, but only 0.02 ppm of free chlorine in hydrochloric acid in the acid compartment was observed. The current efficiency of the anion exchange membrane was 79%. During the 9 months of continuous operation, 2000 ppm of free chlorine was still observed in sulfuric acid in the anode compartment, but only 0.02 ppm of free chlorine in hydrochloric acid in the acid compartment was observed thereafter. The current efficiency of the anion exchange membrane was maintained at 79%.

[0045] Example 4 In Example 1, instead of bubbling with nitrogen gas, except that added to the tank at a flow rate of 0.001Kmol / m ³ of hydroxylamine hydrochloride solution per hour 0.003 m ^3, Example 1 The same operation as described above was performed. At this time,
The amount of hydroxylamine hydrochloride added to the tank was equivalent to 5 mole times the amount of free chlorine observed in Comparative Example 1.

As a result, one week after the start of the operation, 2000 ppm of free chlorine in sulfuric acid in the anode compartment was observed, but only 0.1 ppm of free chlorine in hydrochloric acid in the acid compartment was observed. The current efficiency of the anion exchange membrane was 80%. During the 9 months of continuous operation, 2000 ppm of free chlorine was still observed in sulfuric acid in the anode compartment, but only 0.1 ppm of free chlorine in hydrochloric acid in the acid compartment was observed thereafter. The current efficiency of the anion exchange membrane was maintained at 80%.

Example 5 The procedure of Example 4 was repeated, except that an aqueous solution of 0.001 kmol / m ³ of hydrazine dihydrochloride was added to the tank at a flow rate of 0.005 m ³ per hour instead of the aqueous solution of hydroxylamine hydrochloride. The same operation as in No. 4 was performed.

As a result, one week after the start of operation, 2000 ppm of free chlorine was observed in sulfuric acid in the anode compartment, but only 0.1 ppm of free chlorine in hydrochloric acid in the acid compartment was observed. The current efficiency of the anion exchange membrane was 80%. During the 9 months of continuous operation, 2000 ppm of free chlorine was still observed in sulfuric acid in the anode compartment, but only 0.1 ppm of free chlorine in hydrochloric acid in the acid compartment was observed thereafter. The current efficiency of the anion exchange membrane was maintained at 80%.

Example 6 The same operation as in Example 4 was performed, except that the flow rate of the aqueous solution of hydroxylamine hydrochloride was changed to 0.03 m ^{3 /} h. At this time, the amount of the hydroxylamine hydrochloride aqueous solution added to the tank was equivalent to 50 mol times the amount of free chlorine observed in Comparative Example 1.

As a result, one week after the start of the operation, 2000 ppm of free chlorine in sulfuric acid in the anode compartment was observed, but only 0.02 ppm of free chlorine in hydrochloric acid in the acid compartment was observed. The current efficiency of the anion exchange membrane was 80%. During the 9 months of continuous operation, 2000 ppm of free chlorine was still observed in sulfuric acid in the anode compartment, but only 0.02 ppm of free chlorine in hydrochloric acid in the acid compartment was observed thereafter. The current efficiency of the anion exchange membrane was maintained at 80%.

Example 7 In Example 1, instead of bubbling with nitrogen gas, a filling tank filled with 10 kg of activated carbon was installed in the middle of the circulation supply path, and replaced with 10 kg of new activated carbon every month. Except for this, the same operation as in Example 1 was performed.

As a result, one week after the start of the operation, 2000 ppm of free chlorine in sulfuric acid in the anode compartment was observed, but only 0.2 ppm of free chlorine in hydrochloric acid in the acid compartment was observed. The current efficiency of the anion exchange membrane was 79%. During the 9 months of continuous operation, 2000 ppm of free chlorine was still observed in the sulfuric acid in the anode compartment, but only 0.2 ppm in the hydrochloric acid in the acid compartment. The current efficiency of the anion exchange membrane was maintained at 79%.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a typical electrolytic cell used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; Cathode 2; Anode 3; Cation exchange membrane 4; Anion exchange membrane 5; Cation exchange membrane 6; Raw material chamber 7; Cathode chamber 8; Acid chamber 9; Anode chamber 10; Circulation supply channel 11; Circulating pump

Claims (5)

[Claims] At least one cation exchange membrane, at least one anion exchange membrane, and at least one cation exchange membrane are arranged between an anode and a cathode in this order from the anode side. By this, the anode chamber where the anode exists, the acid chamber separated on the anode side by a cation exchange membrane and the cathode side separated by an anion exchange membrane, the anode side separated by an anion exchange membrane, and the cathode side separated by a cation exchange membrane A raw material chamber, a cathode chamber in which a cathode is present, and an electrolytic cell having an intermediate chamber separated by two cation exchange membranes or anion exchange membranes when a plurality of the same ion exchange membranes are used, In the method for producing quaternary ammonium hydroxide, in which a quaternary ammonium halide aqueous solution is supplied to the raw material chamber to perform electrolysis and quaternary ammonium hydroxide is generated in the cathode chamber, an anode chamber, A quaternary hydroxide, wherein at least one chamber liquid selected from the chamber and an intermediate chamber located between the anode chamber and the acid chamber is circulated and supplied while removing free halogens. Method for producing ammonium. 2. The method for producing a quaternary ammonium hydroxide aqueous solution according to claim 1, wherein the treatment for removing free halogens is an aeration treatment. 3. The method for producing a quaternary ammonium hydroxide aqueous solution according to claim 1, wherein the treatment for removing free halogens is a blending of a reducing substance. 4. The method for producing a quaternary ammonium hydroxide aqueous solution according to claim 1, wherein the treatment for removing free halogens is contact with an adsorbent. 5. The concentration of free halogens in an acid chamber is 10 pp.
5. The method for producing a quaternary ammonium hydroxide aqueous solution according to claim 1, wherein the aqueous solution is kept at m or less.