Chlorine dioxide generation method

Abstract

To provide a method for generating chlorine dioxide in solution without using catalysts or hypochlorites, and a method for efficiently generating chlorine dioxide by light application under neutral to basic conditions, which has been difficult with sodium chlorite due to superior corrosion resistance and safety aspects.SOLUTION: A method for generating chlorine dioxide is characterized by applying light including ultraviolet light to an aqueous solution containing chlorite represented by the following formula (1) and adjusted to pH 6 or higher. (In formula (1), R11, R21, R31, and R41 are each an alkyl group, and may contain an ether bond, a ketone (carbonyl group), an ester bond, or an amide bond, or an aromatic ring.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for generating chlorine dioxide by irradiating an aqueous solution of chlorite with light to generate chlorine dioxide.

Background Art

[0002] Chlorine dioxide (ClO2) is a gas having a strong oxidizing power at normal temperature and pressure. It is widely used not only in the form of gas but also dissolved in solvents such as water as a bactericide, disinfectant, fungicide, deodorant, bleaching agent, and various oxidizing agents.

[0003] However, chlorine dioxide is very unstable, and high-concentration chlorine dioxide gas has explosiveness. Therefore, a method of generating chlorine dioxide gas at the actual place of use is adopted.

[0004] A general method for generating chlorine dioxide is to add an acid to metal chlorites such as sodium chlorite. In addition, there are methods such as adding a catalyst or hypochlorite to metal chlorite as described in Patent Documents 1 and 2. Further, a method of irradiating light on a metal chlorite added with an acid as described in Patent Document 3 is known.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] As a method for generating chlorine dioxide using a solution, an acid, a catalyst, a hypochlorite, etc. are used in an aqueous solution of metal chlorites such as sodium chlorite. In the above Patent Document 1, a radical generation catalyst using an ammonium salt is used in a metal chlorite solution, and in Patent Document 2, an aqueous solution of a metal hypochlorite is added to a metal chlorite solution to generate chlorine dioxide. However, in Patent Documents 1 and 2, since it is necessary to add a catalyst or a hypochlorite and it is difficult to control the reaction, there is a problem that a large amount of chlorine dioxide is generated at the initial stage of the reaction.

[0007] In Patent Document 3, a pH buffer is added to an aqueous solution of a metal chlorite, and chlorine dioxide is generated by irradiating ultraviolet light under acidic conditions. However, the method of irradiating ultraviolet light to an aqueous solution of a metal chlorite has low chlorine dioxide generation efficiency, is limited to acidic conditions, and has problems in terms of corrosiveness and safety under acidic conditions. Further, in Patent Document 3, when sodium chlorite is used as the metal chlorite, an example in which the chlorine dioxide generation efficiency decreases in the neutral to basic region is described.

[0008] Therefore, an object of the present invention is to provide a method for generating chlorine dioxide in a solution without using a catalyst or a hypochlorite. Another object is to provide an efficient method for generating chlorine dioxide by light irradiation, which has been difficult with sodium chlorite under neutral to basic conditions that are excellent in terms of corrosiveness and safety.

Means for Solving the Problems

[0009] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by irradiating an aqueous solution containing a specific chlorite with light containing ultraviolet light, and have completed the present invention. That is, the present invention having the following content has been completed.

[0010] [1] A method for generating chlorine dioxide, characterized by irradiating an aqueous solution containing a chlorite represented by the following formula (1) and adjusted to a pH of 6 or more with light containing ultraviolet light.

Chemical formula

[0011] According to the present invention, when generating chlorine dioxide, an aqueous solution containing the substance represented by the chemical formula (1) and light containing ultraviolet light are used to provide a method for generating chlorine dioxide in a solution without using a catalyst or hypochlorite. Further, an efficient method for generating chlorine dioxide by light irradiation, which has been difficult with sodium chlorite under neutral to basic conditions with a pH of 6 or more, which is excellent in terms of corrosiveness and safety, can be provided.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the method for generating chlorine dioxide according to the present invention will be described.

[0013] (Method for Generating Chlorine Dioxide) Dissolve the chlorite represented by the following chemical formula (1) in water and adjust the pH to 6 or more to obtain an aqueous solution. Then, irradiate the aqueous solution with light containing ultraviolet light to generate chlorine dioxide. The concentration of the chlorite in the aqueous solution is not particularly limited and may be appropriately set according to the amount of chlorine dioxide generated.

[0014] As the direction of irradiating the light containing ultraviolet light, it may be from any direction, up and down, left and right, or front and back, with respect to the aqueous chlorite solution.

[0015] As the light containing ultraviolet light, either an irradiator or sunlight may be used. Examples of the irradiator include irradiators capable of irradiating light of a single wavelength or a mixed wavelength using laser light, lamp light, LED light, etc. When using an irradiator, the wavelength of the irradiated light is preferably 200 nm or more and 500 nm or less, and more preferably 254 nm or 365 nm from the viewpoint of chlorine dioxide generation efficiency. The amount of irradiated light is not particularly limited and may be appropriately set according to the amount of chlorine dioxide generated.

[0016] (Explanation of Chlorite) Next, the chlorite used in the method for generating chlorine dioxide of the present invention is represented by the following formula (1). [Chemical formula] (In the above formula (1), R 11 , R 21 , R 31 , and R 41 are each an alkyl group, and may contain an ether bond, a ketone (carbonyl group), an ester bond, or an amide bond, or an aromatic ring. R 11 , R 21 , R 31 , and R 41 may be the same or different from each other. R 11 , R 21 , R 31 , or R 41 contains at least one electron-withdrawing group.)

[0017] In the alkyl group of R 11 , R 21 , R 31 , or R 41 in the chlorite of the formula (1), when the carbon atom bonded to the nitrogen atom in the formula (1) is defined as the first carbon atom, the carbon atom bonded to the first carbon atom is defined as the second carbon atom, the carbon atom bonded to the second carbon atom is defined as the third carbon atom, and the carbon atom bonded to the third carbon atom is defined as the fourth carbon atom, it is preferable that the electron-withdrawing group is bonded to any one of the first to fourth carbon atoms. Note that in the alkyl group of R 11 , R 21 , R 31 , or R 41 , the number of carbon atoms is not always four or more and may be less than four. For example, when the number of carbon atoms contained in the alkyl group of R 11 , R 21 , R 31 , or R 41 is three, the carbon atom bonded to the nitrogen atom in the formula (1) is defined as the first carbon atom, the carbon atom bonded to the first carbon atom is defined as the second carbon atom, the carbon atom bonded to the second carbon atom is defined as the third carbon atom, and it is preferable that the electron-withdrawing group is bonded to any one of the first to third carbon atoms. R 11 , R21 , R 31 or R 41 When the number of carbon atoms contained in the alkyl group of or is 2, the carbon atom bonded to the nitrogen atom in the formula (1) is defined as the first carbon atom, the carbon atom bonded to the first carbon atom is defined as the second carbon atom, and it is preferable that the electron-withdrawing group is bonded to either the first or second carbon atom. R 11 , R 21 , R 31 or R 41 When the number of carbon atoms contained in the alkyl group of or is 1, the carbon atom bonded to the nitrogen atom in the formula (1) is defined as the first carbon atom, and it is preferable that the electron-withdrawing group is bonded to the first carbon atom.

[0018] Further, the chain-like substituent of the chlorite (for example, a hydrocarbon group such as an alkyl group or an unsaturated aliphatic hydrocarbon group) may be linear or branched unless otherwise specified, and the number of carbon atoms is not particularly limited. For example, it may be 1 to 40, 1 to 32, 1 to 24, 1 to 18, 1 to 12, 1 to 6, or 1 to 2 (2 or more in the case of an unsaturated hydrocarbon group). In the present invention, the number of ring members (the number of atoms constituting the ring) of an aromatic ring or a cyclic group (for example, an aryl group, a heteroaryl group, etc.) is not particularly limited. For example, it may be 5 to 32, 5 to 24, 6 to 18, 6 to 12, or 6 to 10. When isomers exist in substituents or the like, any isomer may be used unless otherwise specified. For example, when simply referred to as a "naphthyl group", it may be a 1-naphthyl group or a 2-naphthyl group.

[0019] The electron-withdrawing group is not particularly limited, and examples thereof include a halogen group, a nitro group, an amino group, a cyano group, a carbonyl group, a carboxy group, a sulfone group, a methoxy group, and a hydroxy group. From the viewpoint of easily releasing chlorite ions, a hydroxy group is preferable.

[0020] The chlorite is not particularly limited, and examples thereof include 2-hydroxyethyltrimethylammonium chlorite, bis(2-hydroxyethyl)dimethylammonium chlorite, and tris(2-hydroxyethyl)methylammonium chlorite. From the viewpoint of chlorine dioxide generation efficiency, 2-hydroxyethyltrimethylammonium chlorite is preferable.

[0021] The above-mentioned chlorite (quaternary ammonium chlorite) can be produced by reacting an ammonium salt represented by the following formula (2) with chlorine dioxide.

Chemical formula

[0022] The electron-withdrawing group is not particularly limited, and examples thereof include a halogen group, a nitro group, an amino group, a cyano group, a carbonyl group, a carboxy group, a sulfone group, a methoxy group, and a hydroxy group. From the viewpoint of facilitating the release of chlorite ions, a hydroxy group is preferable.

[0023] In the formula (2), R 11 , R 21 , R 31 , or R 41In the alkyl group, when the carbon atom bonded to the nitrogen atom in the formula (2) is defined as the first carbon atom, the carbon atom bonded to the first carbon atom is defined as the second carbon atom, the carbon atom bonded to the second carbon atom is defined as the third carbon atom, and the carbon atom bonded to the third carbon atom is defined as the fourth carbon atom, it is preferable that the electron-withdrawing group is bonded to any one of the first to fourth carbon atoms. Note that R 11 、R 21 、R 31 、or R 41 In the alkyl group, the number of carbon atoms does not always have to be 4 or more, and may be less than 4. For example, when the number of carbon atoms contained in the alkyl group of R 11 、R 21 、R 31 、or R 41 is 3, the carbon atom bonded to the nitrogen atom in the formula (2) is defined as the first carbon atom, the carbon atom bonded to the first carbon atom is defined as the second carbon atom, the carbon atom bonded to the second carbon atom is defined as the third carbon atom, and it is preferable that the electron-withdrawing group is bonded to any one of the first to third carbon atoms. R 11 、R 21 、R 31 、or R 41 When the number of carbon atoms contained in the alkyl group is 2, the carbon atom bonded to the nitrogen atom in the formula (2) is defined as the first carbon atom, the carbon atom bonded to the first carbon atom is defined as the second carbon atom, and it is preferable that the electron-withdrawing group is bonded to any one of the first to second carbon atoms. R 11 、R 21 、R 31 、or R 41 When the number of carbon atoms contained in the alkyl group is 1, the carbon atom bonded to the nitrogen atom in the formula (2) is defined as the first carbon atom, and it is preferable that the electron-withdrawing group is bonded to the first carbon atom.

[0024] The chlorite (the quaternary ammonium chlorite) is not particularly limited. For example, R 11 、R 21 、R 31 、R 41When they are each a linear alkyl group having 1 to 6 carbon atoms, R 11 is one in which a hydroxy group is bonded as an electron-withdrawing group to any one of the first to sixth carbon atoms counted from the side closer to the nitrogen atom, or R 11 R 21 is one in which a hydroxy group is bonded as an electron-withdrawing group to any one of the first to sixth carbon atoms counted from the side closer to the nitrogen atom in each of the alkyl groups of R 11 R 21 R 31 is one in which a hydroxy group is bonded as an electron-withdrawing group to any one of the first to sixth carbon atoms counted from the side closer to the nitrogen atom in each of the alkyl groups of R 11 R 21 R 31 R 41 R

[0025] Furthermore, when R 11 R 21 R 31 R 41 in formula (2) are each an alkyl group having 1 to 2 carbon atoms, R 11 is one in which a hydroxy group is bonded as an electron-withdrawing group to either the first or second carbon atom counted from the side closer to the nitrogen atom, or R 11 R 21 is one in which a hydroxy group is bonded as an electron-withdrawing group to either the first or second carbon atom counted from the side closer to the nitrogen atom in each of the alkyl groups of R 11 R 21 R 31 is one in which a hydroxy group is bonded as an electron-withdrawing group to either the first or second carbon atom counted from the side closer to the nitrogen atom in each of the alkyl groups of R 11 R 21 R 31 R 41、In each of the alkyl groups, it is more preferable that a hydroxy group is bonded as an electron-withdrawing group to either the first or second carbon atom counted from the carbon atom closer to the nitrogen atom.

[0026] Furthermore, R in formula (2) 11 、R 21 、R 31 、are each a methyl group, and 2-hydroxyethyltrimethylammonium hydroxide in which R 41 is 2-hydroxyethyl, or bis(2-hydroxyethyl)dimethylammonium hydroxide in which R 11 、R 21 、are each a methyl group, and R 31 、R 41 、are each 2-hydroxyethyl, or tris(2-hydroxyethyl)methylammonium hydroxide in which R 11 is a methyl group, and R 21 、R 31 、R 41 、are each 2-hydroxyethyl, is particularly preferable. Among them, 2-hydroxyethyltrimethylammonium hydroxide is most preferable.

[0027] (Method for producing chlorite (quaternary ammonium chlorite)) The method for producing a chlorite (quaternary ammonium chlorite) preferably includes a reaction step of bringing a solution of a quaternary ammonium hydroxide salt represented by the above formula (2) into contact with chlorine dioxide. A chlorite (quaternary ammonium chlorite) can be obtained by lyophilizing the chlorite (quaternary ammonium chlorite) solution obtained by the above reaction.

[0028] In the reaction step of bringing the solution of the quaternary ammonium hydroxide salt represented by the above formula (2) into contact with chlorine dioxide, the concentration of the quaternary ammonium hydroxide salt solution is preferably 0.01 to 37.5% by mass, more preferably 0.05 to 30% by mass, and even more preferably 0.1 to 25% by mass.

[0029] By bringing chlorine dioxide into contact and reacting with ammonium in an aqueous solution of a quaternary ammonium hydroxide salt so as to be equimolar with respect to the ammonium, the hydroxide ions of the quaternary ammonium hydroxide are replaced with chlorite ions in the state where chlorine dioxide is ionized, and a chlorite (quaternary ammonium chlorite salt) solution is produced.

[0030] The produced chlorite solution can be freeze-dried to obtain a chlorite (quaternary ammonium salt).

[0031] The chlorite is dissolved in water, and the aqueous chlorite solution is adjusted to pH 6 or higher. Preferably, the pH at 25 °C is 6 or higher, more preferably 6.0 to 14.0 at 25 °C, and particularly preferably 6.0 to 11.0 at 25 °C from the viewpoint of chlorine dioxide generation efficiency. Needless to say, if the pH of the aqueous solution is 6 or higher when the chlorite is dissolved in water, there is no particular need to adjust the pH.

[0032] The aqueous solution of the chlorite may contain a pH adjuster to adjust the pH to 6 or higher. The pH adjuster added to the aqueous solution in which the chlorite is dissolved may be a hydroxide salt having a cation represented by the above formula (1) or (2), or may be, for example, a hydroxide salt, carbonate, bicarbonate, ammonia, monoethanolamine, diethanolamine, guanidine, etc., which are generally used as pH adjusters.

[0033] The pH of the aqueous solution of the chlorite can be measured with a pH meter, and for the pH meter, the product name "LAQUA series" (manufactured by Horiba, Ltd.) can be used.

[0034] The chlorine dioxide generated as described above can be used for the same applications as conventional chlorine dioxide, such as the oxidation of a wide range of substances.

Examples

[0035] Hereinafter, specific examples of the present invention will be described. However, the present invention is not limited to the following examples.

[0036] [Production Example 1] [Preparation of 2-Hydroxyethyltrimethylammonium Chlorite] A 1.46 M solution of 2-hydroxyethyltrimethylammonium hydroxide was prepared, and chlorine dioxide gas was blown in to make it 1.46 M to obtain a 2-hydroxyethyltrimethylammonium chlorite solution. The 2-hydroxyethyltrimethylammonium chlorite solution was lyophilized to obtain a powder of 2-hydroxyethyltrimethylammonium chlorite salt.

[0037] [Example 1] [Adjustment of Aqueous Solution of 2-Hydroxyethyltrimethylammonium Chlorite] The 2-hydroxyethyltrimethylammonium chlorite salt obtained in Production Example 1 was dissolved in ultrapure water to obtain a 7.4 mM aqueous solution of 2-hydroxyethyltrimethylammonium chlorite.

[0038] [pH Measurement Method] The pH was measured using a compact pH meter, "LAQUAtwin-pH-22B" (manufactured by Horiba, Ltd.), after stabilizing at 25°C.

[0039] [Chlorine Dioxide Generation Method] 10 g of a 7.4 mM aqueous solution of 2-hydroxyethyltrimethylammonium chlorite was accurately measured into a screw bottle, and the screw bottle was sealed. The side of the screw bottle was irradiated with light, and the concentration was measured every time a predetermined integrated light amount was reached. The light source was a UV irradiator (Light Hammer6 manufactured by Heraeus, irradiation light amount: about 300 mW / cm 2 ) was used, and the irradiation light wavelength was a mixed wavelength of 200 to 500 nm.

[0040] [Calculation Method of Chlorine Dioxide Concentration] The measurement of the amount of chlorine dioxide generated was calculated as the concentration using absorbance. The absorbance at 360 nm was measured using a spectrophotometer (U-4100 type manufactured by Hitachi High-Tech Corporation), and the chlorine dioxide concentration was calculated from the calibration curve using Lambert-Beer's law. The results obtained are shown in Table 1.

[0041] [Example 2] <Preparation of 2-hydroxyethyltrimethylammonium chlorite aqueous solution> The 2-hydroxyethyltrimethylammonium chlorite salt obtained in Production Example 1 was dissolved in ultrapure water to obtain a 150 mM aqueous solution of 2-hydroxyethyltrimethylammonium chlorite.

[0042] The pH measurement method was carried out in the same manner as in Example 1. As the method for generating chlorine dioxide, 10 g of a 150 mM aqueous solution of 2-hydroxyethyltrimethylammonium chlorite was accurately measured into a screw bottle, and the screw bottle was sealed. Light was irradiated on the side surface of the screw bottle, and the concentration was measured every time a predetermined integrated light amount was reached. The light source was a handy UV-LED irradiator (HANDY POWER LHPH / U365 manufactured by Iida Lighting Co., Ltd., irradiation light amount: about 50 mW / cm 2 ) was used, and the irradiation light wavelength was 365 nm. The method for calculating the generated chlorine dioxide concentration was carried out in the same manner as in Example 1. The results obtained are shown in Table 2.

[0043] [Example 3] The preparation of the 2-hydroxyethyltrimethylammonium chlorite aqueous solution and the pH measurement method were carried out in the same manner as in Example 1. As the method for generating chlorine dioxide, 3 g of a 7.4 mM aqueous solution of 2-hydroxyethyltrimethylammonium chlorite was accurately measured into a rectangular quartz cell (10 mm × 10 mm × 40 mm), and the quartz cell was sealed. Light was irradiated on the side surface of the cell, and the concentration was measured every time a predetermined integrated light amount was reached. The light source was a UV irradiator (Handy UV Lamp SLUV4 manufactured by AS ONE Corporation, irradiation light amount: about 0.9 mW / cm 2 ) was used, and the irradiation light wavelength was 254 nm. The method for calculating the generated chlorine dioxide concentration was carried out in the same manner as in Example 1. The results obtained are shown in Table 3.

[0044] [Comparative Example 1] [Preparation of Sodium Chlorite Salt] A powder of sodium chlorite salt was obtained in the same manner as in Production Example 1, except that sodium hydroxide was used instead of 2-hydroxyethyltrimethylammonium hydroxide.

[0045] [Adjustment of Aqueous Sodium Chlorite Solution] The sodium chlorite salt was dissolved in ultrapure water to obtain a 7.4 mM aqueous solution of sodium chlorite.

[0046] The pH measurement method was carried out in the same manner as in Example 1. Chlorine dioxide was generated in the same manner as in Example 1, and the method for calculating the chlorine dioxide concentration was also carried out in the same manner as in Example 1. The results obtained are shown in Table 1.

[0047] [Comparative Example 2] [Adjustment of Aqueous Sodium Chlorite Solution] The sodium chlorite salt was dissolved in ultrapure water to obtain a 150 mM aqueous solution of sodium chlorite.

[0048] The pH measurement method was carried out in the same manner as in Example 1. Chlorine dioxide was generated in the same manner as in Example 2, and the method for calculating the chlorine dioxide concentration was carried out in the same manner as in Example 1. The results obtained are shown in Table 2.

[0049] [Comparative Example 3] The adjustment of the aqueous sodium chlorite solution was carried out in the same manner as in Comparative Example 1. The pH measurement method was carried out in the same manner as in Example 1. Chlorine dioxide was generated in the same manner as in Example 3, and the method for calculating the chlorine dioxide concentration was carried out in the same manner as in Example 1. The results obtained are shown in Table 3.

[0050] [Table 1]

[0051] [Table 2]

[0052]

Table 3

[0053] As described above, in the examples, by irradiating ultraviolet rays at pH 6 or higher, chlorine dioxide could be generated more efficiently and stably than sodium chlorite in the comparative examples. Although the details are not clear, in the embodiments of the present invention, it is presumed that the photogeneration reaction of chlorine dioxide occurs more than the photodegradation reaction or the photodegradation reaction of the generated chlorine dioxide is suppressed, and thus the generation efficiency is improved. On the other hand, in the comparative examples, the photogeneration reaction of chlorine dioxide occurs in the same manner, but it is presumed that the photodegradation reaction occurs more, resulting in poor generation efficiency. In addition, in the examples, the pH of the aqueous solution was between 6 and 11 during the test.

[0054] [Production Example 2] [Preparation of tris(2-hydroxyethyl)methylammonium chlorite] A 1.46 M aqueous solution of tris(2-hydroxyethyl)methylammonium hydroxide was prepared, and chlorine dioxide gas was blown in to make it 1.46 M to obtain an aqueous solution of tris(2-hydroxyethyl)methylammonium chlorite. The aqueous solution of tris(2-hydroxyethyl)methylammonium chlorite was freeze-dried to obtain a powder of tris(2-hydroxyethyl)methylammonium chlorite salt.

[0055] [Example 4] [Adjustment of aqueous solution of tris(2-hydroxyethyl)methylammonium chlorite] The tris(2-hydroxyethyl)methylammonium chlorite salt obtained in Production Example 2 was dissolved in ultrapure water to obtain a 7.4 mM aqueous solution of tris(2-hydroxyethyl)methylammonium chlorite.

[0056] The pH measurement method was carried out in the same manner as in Example 1. Chlorine dioxide was generated in the same manner as in Example 3, and the method for calculating the chlorine dioxide concentration was carried out in the same manner as in Example 1. The obtained results are shown in Table 4.

[0057] [Comparative Example 4] The aqueous sodium chlorite solution was prepared in the same manner as in Comparative Example 1. The pH measurement method was carried out in the same manner as in Example 1. Chlorine dioxide was generated in the same manner as in Example 3, and the method for calculating the chlorine dioxide concentration was carried out in the same manner as in Example 1. The results obtained are shown in Table 4.

[0058]

Table 4

[0059] Even when tris(2-hydroxyethyl)methylammonium chlorite was used instead of 2-hydroxyethyltrimethylammonium chlorite used in Examples 1 to 3, chlorine dioxide could be efficiently and stably generated more efficiently than sodium chlorite in the comparative example by irradiating ultraviolet rays at pH 6 or higher. In the examples, the pH of the aqueous solution was between 6 and 11 during the test.

Industrial Applicability

[0060] The present invention can easily generate chlorine dioxide without using a catalyst or hypochlorite, and can efficiently and stably generate chlorine dioxide in the liquid under neutral to basic conditions, which is excellent in terms of corrosiveness and safety. Therefore, it can be used for the oxidation of a wide range of substances.

Claims

1. A method for generating chlorine dioxide, characterized by irradiating an aqueous solution containing a chlorite represented by the following formula (1) and adjusted to a pH of 6 or higher with light containing ultraviolet light. 【Chemical Formula 1】 (In the above formula (1), R １１ , R ２１ , R ３１ , and R ４１ are each an alkyl group, and may contain an ether bond, a ketone (carbonyl group), an ester bond, or an amide bond, or an aromatic ring. R １１ , R ２１ , R ３１ , and R ４１ may be the same or different from each other. R １１ , R ２１ , R ３１ , or R ４１ contains at least one electron-withdrawing group.)

2. The method for generating chlorine dioxide according to Claim 1, wherein the electron-withdrawing group of the chlorite is a hydroxy group.

3. The R of the hydrochloride １１ , R ２１ , R ３１ , or R ４１ In the alkyl group, when the carbon atom bonded to the nitrogen atom in the formula (1) is defined as the first carbon atom, the carbon atom bonded to the first carbon atom is defined as the second carbon atom, the carbon atom bonded to the second carbon atom is defined as the third carbon atom, and the carbon atom bonded to the third carbon atom is defined as the fourth carbon atom, the method for generating chlorine dioxide according to claim 1 or claim 2, wherein the electron-withdrawing group is bonded to any one of the first to fourth carbon atoms.

4. The method for generating chlorine dioxide according to Claim 1 or Claim 2, wherein the chlorite represented by the formula (1) is 2-hydroxyethyltrimethylammonium chlorite.

5. The method for generating chlorine dioxide according to Claim 1, wherein the pH of the aqueous solution is 6 to 11 at 25°C.

6. The method for generating chlorine dioxide according to Claim 1, wherein the wavelength of the irradiated light is 200 nm or more and 500 nm or less.

7. The method for generating chlorine dioxide according to Claim 1, wherein the wavelength of the irradiated light is 254 nm or 365 nm.

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