JP7693207B2 - Chlorine dioxide generating device and chlorine dioxide generating method - Google Patents

Description

The present invention relates to a chlorine dioxide generating device and a chlorine dioxide generating method that generate chlorine dioxide gas in a solvent in a container.

Conventionally, there are known tools and devices that generate chlorine dioxide gas by reacting a solution of chlorite with an acidic substance (for example, Patent Document 1).

JP 2007-145654 A

In the method of generating chlorine dioxide gas described in Patent Document 1, for example, a large amount of high-concentration chlorine dioxide gas is generated at the beginning of the reaction, and low-concentration chlorine dioxide gas is generated after a certain period of time has passed. For example, when it is desired to sterilize a room or other similar space with chlorine dioxide gas in an environment where people are present, it is necessary to stably generate a relatively low-concentration chlorine dioxide gas for a long period of time from the beginning of the reaction.

Therefore, the object of the present invention is to provide a chlorine dioxide generating device and a chlorine dioxide generating method that can stably and controllably generate chlorine dioxide gas from the early stages of the reaction.

The chlorine dioxide generator according to the present invention for achieving the above object has a characteristic configuration in which, in a solvent in a container, a chlorite, an acidic substance which reacts with the chlorite to generate chlorine dioxide gas, and a buffer substance which is a salt or conjugate base of the acidic substance and has a buffering effect on the acidic substance are mixed to generate chlorine dioxide gas, and the buffer substance is configured to mix with a chlorite aqueous solution before mixing the chlorite with the acidic substance.

In the chlorine dioxide generator of the present invention, chlorite reacts with an acidic substance in a solvent in a container to generate chlorine dioxide gas. At this time, since a buffering substance, which is a salt or conjugate base of the acidic substance that has a buffering effect on the acidic substance, is present in the solvent, the pH of the solvent is less likely to fluctuate (it can be kept substantially constant) when chlorite reacts with the acidic substance to generate chlorine dioxide. Therefore, chlorine dioxide gas can be generated in a stable and controlled manner from the early stage of the reaction between chlorite and the acidic substance.

In Example 1 described below, when a buffer substance is added to the reaction system of chlorite and an acidic substance, a low concentration of chlorine dioxide gas is generated at the beginning of the reaction, and the amount of chlorine dioxide gas generated thereafter maintains the low concentration at the beginning of the reaction for a long period of time. On the other hand, when a buffer substance is not added to the reaction system of chlorite and an acidic substance, a high concentration of chlorine dioxide gas is generated suddenly and in large quantities at the beginning of the reaction, and the amount of chlorine dioxide gas generated thereafter decreases rapidly.

Therefore, when a buffer substance is added to the reaction system of chlorite and an acidic substance as in the chlorine dioxide generator of the present invention, the concentration of chlorine dioxide gas at the initial stage of the reaction can be suppressed compared to the case where a buffer substance is not added, so that the generation period of chlorine dioxide gas can be dramatically extended while maintaining the generated concentration of chlorine dioxide gas at the initial stage of the reaction.
In addition, in this configuration, before mixing chlorite and acidic substance, buffering substance is mixed with chlorite aqueous solution.By dissolving buffering substance in chlorite aqueous solution, buffering substance can be made uniform in chlorite aqueous solution, and when acidic substance is mixed in this state, when chlorite reacts with acidic substance to generate chlorine dioxide, pH of solvent is less likely to change.Therefore, concentration at the beginning of reaction can be reliably suppressed, and chlorine dioxide gas generation period can be further extended while maintaining the generation concentration at the beginning of reaction.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the chlorite is sodium chlorite or potassium chlorite, and the acidic substance is any one of an inorganic acid, an organic acid, and an amphipathic substance.

According to this configuration, sodium chlorite or potassium chlorite as the chlorite is easily available, so the present invention can be easily implemented. In addition, if the acidic substance is any of an inorganic acid, an organic acid, and an amphipathic substance, it can react with the chlorite, sodium chlorite or potassium chlorite, to generate chlorine dioxide.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the acidic substance is a phosphoric acid compound.

According to this configuration, if the acidic substance is a phosphate compound, it is easy to obtain, and therefore the present invention can be easily implemented.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the acidic substance is sodium dihydrogen phosphate or potassium dihydrogen phosphate.

According to this configuration, the acidic substance sodium dihydrogen phosphate or potassium dihydrogen phosphate has excellent storage stability, does not generate corrosive gases, and is easy to handle, making it easy to implement the present invention.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the buffer substance is a phosphate.

According to this configuration, if the buffering substance is a phosphate, it can reliably exert a buffering effect on the phosphate compound (sodium dihydrogen phosphate or potassium dihydrogen phosphate) as an acidic substance in the solvent in the container.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the buffering substance contains at least one of tripotassium phosphate, trisodium phosphate, dipotassium hydrogen phosphate and disodium hydrogen phosphate.

According to this configuration, the buffer substances tripotassium phosphate, trisodium phosphate, dipotassium hydrogen phosphate and disodium hydrogen phosphate are easily available, so that the present invention can be easily implemented.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the acidic substance is acetic acid.

According to this configuration, if the acidic substance is acetic acid, it is easy to obtain, has excellent storage stability, does not generate corrosive gases, and is easy to handle, making it easy to implement the present invention.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the buffer substance is an acetate salt.

According to this configuration, if the buffering substance is an acetate salt, it can reliably exert a buffering effect on acetic acid, which is an acidic substance, in the solvent in the container.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the buffering substance contains at least one of potassium acetate and sodium acetate.

According to this configuration, the present invention can be easily implemented because the buffer substances potassium acetate and sodium acetate are easily available.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the acidic substance is citric acid.

According to this configuration, if the acidic substance is citric acid, it is easy to obtain, has excellent storage stability, does not generate corrosive gases, and is easy to handle, making it easy to implement the present invention.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the buffer substance is a citrate salt.

According to this configuration, if the buffering substance is a citrate salt, it can reliably exert a buffering effect on citric acid, which is an acidic substance, in the solvent in the container.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the buffering substance contains at least one of potassium citrate and sodium citrate.

According to this configuration, the present invention can be easily implemented because the buffer substances potassium citrate and sodium citrate are easily available.

A further characteristic feature of the chlorine dioxide generator of the present invention is that the pH of the solvent is 5 to 7.

According to this configuration, by setting the pH of the solvent to 5 to 7, it is possible to more stably control and generate low-concentration chlorine dioxide gas from the early stage of the reaction (see Example 5 described below).

A further characteristic feature of the chlorine dioxide generating device according to the present invention is that the concentration of the chlorite is 3 to 25% by weight.

In Example 2 described later, the amount of chlorine dioxide gas generated was investigated when the concentration of the chlorite aqueous solution was changed in various ways (3 to 25% by weight). As a result, it was found that the concentration of chlorine dioxide gas at the initial stage of the reaction can be suppressed, and the generation period of chlorine dioxide gas can be dramatically extended while maintaining the generation concentration of chlorine dioxide gas at the initial stage of the reaction.
Therefore, in consideration of safety, stability, and efficiency of generating chlorine dioxide gas, the concentration of chlorite should be 3 to 25% by weight.

A further characteristic feature of the chlorine dioxide generator of the present invention is that a gelling agent is added to the solvent in the container.

According to this configuration, the solvent in the container can be gelled by adding a gelling agent.
Therefore, even if the container is tilted, the gelled solvent is unlikely to spill out of the container, making the chlorine dioxide generator easy to handle.

The chlorine dioxide generating method according to the present invention is characterized in that, in the method for generating chlorine dioxide gas, a chlorite, an acidic substance which reacts with the chlorite to generate chlorine dioxide gas, and a buffering substance which is a salt or a conjugate base of the acidic substance and has a buffering effect on the acidic substance are mixed in a solvent in a container, the buffering substance is mixed with the chlorite aqueous solution before mixing the chlorite with the acidic substance.

In the chlorine dioxide generation method of the present invention, chlorite reacts with an acidic substance in a solvent in a container to generate chlorine dioxide gas. At this time, since a buffering substance, which is a salt or conjugate base of the acidic substance that has a buffering effect on the acidic substance, is present in the solvent, the pH of the solvent is less likely to fluctuate (it can be kept substantially constant) when chlorite reacts with the acidic substance to generate chlorine dioxide. Therefore, chlorine dioxide gas can be generated in a stable and controlled manner from the early stage of the reaction between chlorite and the acidic substance.

Therefore, when a buffer substance is added to the reaction system of chlorite and an acidic substance as in the chlorine dioxide generating method of the present invention, the concentration of chlorine dioxide gas at the initial stage of the reaction can be suppressed compared to the case where a buffer substance is not added, so that the generation period of chlorine dioxide gas can be dramatically extended while maintaining the generated concentration of chlorine dioxide gas at the initial stage of the reaction.
In addition, in this configuration, before mixing chlorite and acidic substance, buffering substance is mixed with chlorite aqueous solution.By dissolving buffering substance in chlorite aqueous solution, buffering substance can be made uniform in chlorite aqueous solution, and when acidic substance is mixed in this state, when chlorite reacts with acidic substance to generate chlorine dioxide, pH of solvent is less likely to change.Therefore, concentration at the beginning of reaction can be reliably suppressed, and chlorine dioxide gas generation period can be further extended while maintaining the generation concentration at the beginning of reaction.

A further characteristic feature of the chlorine dioxide generating method according to the present invention is that the acidic substance and the gelling agent are mixed in a state in which the buffer substance is dissolved in the aqueous chlorite solution.

According to this configuration, the solvent in the container can be gelled by adding a gelling agent.
Therefore, even if the container is tilted, the gelled solvent is unlikely to spill out of the container, making it easy to carry out the chlorine dioxide generating method.

FIG. 1 is a schematic diagram showing a chlorine dioxide generating device according to an embodiment. 1 is a graph showing the relationship between the amount of chlorine dioxide gas generated and time (Example 1). 1 is a graph showing the relationship between the amount of chlorine dioxide gas generated and time (Example 2). 1 is a graph showing the relationship between the amount of chlorine dioxide gas generated and time (Example 3). 1 is a graph showing the relationship between the amount of chlorine dioxide gas generated and time (Example 4). 1 is a graph showing the results of an investigation into how the amount of chlorine dioxide gas generated changes when the pH of the reaction system is changed by changing the amount of a buffer substance added (Example 5). 1 is a graph showing the results of an investigation into how the amount of chlorine dioxide gas generated changes when the mode of adding a buffer substance is changed (Example 6). FIG. 1 is a schematic diagram of a chlorine dioxide generation device (pouch type) of another embodiment. 1 is a graph showing the results of an investigation into how chlorine dioxide gas is generated when the container is in the form of a pouch (Example 7). 1 is a graph showing the results of an investigation into how chlorine dioxide gas is generated when a gelling agent is added (Example 8).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The chlorine dioxide generator of the present invention generates chlorine dioxide gas by mixing, in a solvent in a container, a chlorite, an acidic substance that reacts with the chlorite to generate chlorine dioxide gas, and a buffering substance that is a salt or conjugate base of the acidic substance that has a buffering effect on the acidic substance.The chlorine dioxide generating method of the present invention generates chlorine dioxide gas by mixing, in a solvent in a container, a chlorite, an acidic substance that reacts with the chlorite to generate chlorine dioxide gas, and a buffering substance that is a salt or conjugate base of the acidic substance that has a buffering effect on the acidic substance.

The reaction between the chlorite and the acidic substance is configured to take place in a solvent in the container. The solvent is preferably an aqueous solution. At this time, at least one of the chlorite and the acidic substance is in the form of an aqueous solution, and the two are mixed in the container to react. In this embodiment, a case where the chlorite is an aqueous chlorite solution is described. In this case, the acidic substance may be in the form of a powder, a solid, or a liquid. In this embodiment, a case where a powdered acidic substance is used is described.

Figure 1 shows a chlorine dioxide generator X in which an acidic substance B is added to a solvent (aqueous chlorite solution A) in a container 1 having an opening at one end, and the two are mixed and reacted in the container 1 to generate chlorine dioxide gas. The container 1 of this embodiment may be a container (chlorite storage section 12) capable of storing the aqueous chlorite solution A. The acidic substance B may be stored in a container (acidic substance storage section 13) outside the container 1, and the acidic substance B may be added to the container 1 when the chlorine dioxide generator X is used. The opening of the container 1 serves as a gas release section 11 capable of releasing gas.

The buffer substance C, which is a salt or conjugate base of the acidic substance B that has a buffering effect on the acidic substance B, may be used in either a solid or liquid form. The buffer substance C is preferably dissolved or mixed in the chlorite aqueous solution A or the acidic substance B (powder, solid, or liquid) before mixing the chlorite aqueous solution A and the acidic substance B. In this embodiment, a case will be described in which the buffer substance C is dissolved in the chlorite aqueous solution A and then mixed with the acidic substance B.

The shape of the container 1 may be, but is not limited to, a bottle, a tube (test tube), a stick, a bag (pouch), a box, etc. In this embodiment, the container 1 is described as being bottle-shaped. The material of the container 1 is not particularly limited as long as it is a material that is heat-resistant and chemical-resistant. Glass, metals such as stainless steel, and resins such as polypropylene, polyethylene, and Tritan (registered trademark, manufactured by Eastman Co.), which have excellent heat and chemical resistance, are particularly preferred.

The gas release section 11 may be an open system, but may be provided with a lid having a structure with breathability or a non-permeable member with breathability. These members may be attached to the opening of the container 1 after the acidic substance B is added to the container 1. The non-permeable member may be, for example, a moisture-permeable waterproof sheet (or a breathable waterproof sheet) that allows gas, air, and moisture to pass through but does not allow liquid to pass through. The moisture-permeable waterproof sheet may be a microporous film (a film made of a material having many very small holes) used alone, or a material made by laminating multiple sheets together, a material that is nonporous but allows the movement of gas, air, and moisture (water vapor), or a coating type material in which a high-density woven fabric is subjected to a strong water-repellent treatment. Examples of materials on the market include Gore-Tex (registered trademark), Exepol (registered trademark, manufactured by Mitsubishi Plastics), Porum (registered trademark, manufactured by Tokuyama Corporation), Entrant E (registered trademark, manufactured by Toray Industries, Inc.), Tyvek (registered trademark, manufactured by DuPont), and Melfit (registered trademark, manufactured by Unicel Corporation). In order to facilitate attachment to the container 1, the water-impermeable member desirably has heat sealability (thermal welding property).

(Chlorite)
The chlorite used in the present invention can be, for example, alkali metal chlorite or alkaline earth metal chlorite.The alkali metal chlorite can be, for example, sodium chlorite, potassium chlorite, and lithium chlorite, and the alkaline earth metal chlorite can be, for example, calcium chlorite, magnesium chlorite, and barium chlorite.Among them, sodium chlorite and potassium chlorite are preferred from the viewpoint of easy availability, and sodium chlorite is most preferred.These chlorites can be used alone or in combination of two or more.

The proportion of chlorite in the chlorite aqueous solution is preferably 0.1 to 30% by weight. If it is less than 0.1% by weight, there is a possibility that there will be a problem of insufficient chlorite in the generation of chlorine dioxide gas, and if it exceeds 30% by weight, there is a possibility that there will be a problem of saturation of chlorite and easy precipitation of crystals. In consideration of safety, stability, and the efficiency of generation of chlorine dioxide gas, a proportion of 3 to 25% by weight is preferable, and a more preferable range is 3 to 15% by weight.

(acidic substance)
The acidic substance that can be used in the present invention is an acid that reacts with chlorite, and is not particularly limited as long as it is preferably any of inorganic acids, organic acids, and amphipathic substances. Examples of the acidic substance include, for example, phosphoric acid compounds (sodium dihydrogen phosphate or potassium dihydrogen phosphate), acetic acid, sulfuric acid, etc. in the case of inorganic acids, citric acid, malic acid, lactic acid, etc. in the case of organic acids, and 3-morpholinopropanesulfonic acid, 2-morpholinoethanesulfonic acid, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, etc. in the case of amphipathic substances. Among them, it is preferable to use phosphoric acid compounds (sodium dihydrogen phosphate or potassium dihydrogen phosphate), acetic acid, and citric acid because they have excellent storage stability, do not generate corrosive gases, and do not change in concentration during storage. The acidic substance may be used alone or in combination of two or more types. In addition, the acidic substance may be in the form of either anhydride or hydrate.

The acidic substance may be contained in a porous substance. The porous substance may be, for example, a porous material or a burned aggregate, but is not limited thereto.
Examples of porous materials include porous silica, sepiolite, montmorillonite, diatomaceous earth, talc, zeolite, activated clay, molecular sieve, activated alumina, etc. Among them, it is preferable to use porous silica, which is easily available, has excellent porosity (wide pore space), and can easily contain acidic substances or chlorite. There is no particular limitation on the specific surface area of these porous silicas, etc. Examples of fired aggregates that can be used include bones of animals (including mammals, fish, and birds), shells, and coral that have been fired into crushed pieces, particles, or powder.

When contained in such a porous material, it is preferable for the final concentration of the acidic substance to be 30% by weight or less.

(buffering substance)
The buffering substance that can be used in the present invention is not particularly limited as long as it is a salt or conjugate base thereof that has a buffering effect on an acidic substance. A substance that corresponds to "a salt or conjugate base thereof that has a buffering effect on an acidic substance" is a "salt of an acidic substance" or a "conjugate base of an acidic substance". One type of buffering substance may be used alone, or two or more types may be used in combination.

When an inorganic acid phosphate compound (sodium dihydrogen phosphate or potassium dihydrogen phosphate) is used as the acidic substance, the buffering substance may contain at least one of the phosphate salts of tripotassium phosphate, trisodium phosphate, dipotassium hydrogen phosphate, and disodium hydrogen phosphate. When an inorganic acid acetic acid is used as the acidic substance, the buffering substance may contain at least one of the acetate salts of potassium acetate and sodium acetate. When an organic acid citric acid is used as the acidic substance, the buffering substance may contain at least one of the citrate salts of potassium citrate and sodium citrate. The buffering substance may be in either an anhydrous or hydrate form.

By dissolving the buffering substance C in the aqueous chlorite solution A, the buffering substance C can be made uniform in the aqueous chlorite solution A. When an acidic substance B is mixed in this state, the pH of the solvent is less likely to fluctuate when the chlorite reacts with the acidic substance to produce chlorine dioxide.

In this embodiment, the buffer substance C is dissolved in the aqueous chlorite solution A and then mixed with the acidic substance B, but a gelling agent may also be added together with the acidic substance B and mixed.

The gelling agent may be a water-absorbent gelling agent, such as a water-absorbent resin, but is not limited to this form. Examples of the water-absorbent resin include AQUALIC (registered trademark, manufactured by Nippon Shokubai Co., Ltd.), SANFRESH (registered trademark, manufactured by Sanyo Chemical Industries, Ltd.), AQUAKEEP (registered trademark, manufactured by Sumitomo Seika Chemicals Co., Ltd.), and KI GEL (registered trademark, manufactured by Kuraray Co., Ltd.), but are not limited to these.

The timing of adding the gelling agent to container 1 is not limited to the above embodiment, and the gelling agent may be added after the buffer substance C is dissolved in the aqueous chlorite solution A and the acidic substance B is mixed therewith.

By adding a gelling agent, the solvent in the container 1 can be gelled, so that even if the container 1 is tilted, the gelled solvent is less likely to spill from the container 1, making the chlorine dioxide generator X easy to handle.

In the chlorine dioxide generator X of the present invention, chlorite reacts with an acidic substance in a solvent in a container to generate chlorine dioxide gas. At this time, since a buffering substance, which is a salt or conjugate base of the acidic substance that has a buffering effect on the acidic substance, is present in the solvent, it is possible to reduce (maintain approximately constant) the pH fluctuation of the solvent when chlorite reacts with the acidic substance to generate chlorine dioxide. Therefore, chlorine dioxide gas can be generated in a stable and controlled manner from the early stage of the reaction between chlorite and the acidic substance.

Therefore, when a buffer substance is added to a reaction system between chlorite and an acidic substance, as in the chlorine dioxide generator X of the present invention, the initial reaction concentration of chlorine dioxide gas can be suppressed compared to when a buffer substance is not added, and the generation period can be dramatically extended while maintaining the generated concentration of chlorine dioxide gas at the initial reaction time.

The pH of the solvent is preferably 5 to 7. In this case, the pH of the solvent is the pH value in a state in which the sodium chlorite aqueous solution A, the acidic substance B, and the buffer substance C are mixed, and can be adjusted by the amount of buffer substance C added. If the pH is within this range, low-concentration chlorine dioxide gas can be stably and controlled to be generated from the early stage of the reaction. Preferably, the pH of the solvent is adjusted to 5.5 to 7, which can further suppress the amount of chlorine dioxide gas generated in the early stage of the reaction, and more preferably, the pH of the solvent is adjusted to 6 to 7, which can further suppress the amount of chlorine dioxide gas generated in the early stage of the reaction.

There is no particular limit to the places where the chlorine dioxide generator X of the present invention can be used, and it can be used in a variety of situations, such as in ordinary homes (living rooms, entrances, bathrooms, kitchens, etc.), industrial (factory) use, medical facilities such as hospitals, clinics, and nursing homes, and public facilities such as schools, train stations, and public toilets. It can also be used not only in relatively large spaces such as indoor spaces where people can live, but also in small spaces such as refrigerators, shoe cabinets, and the inside of vehicles (cars, buses, and trains). In this way, there is no particular limit to the size of the space to which the generator of the present invention can be applied.

[Another embodiment 1]
The present invention is not limited to the above embodiment, and may be applied to an embodiment in which a solid (powdered) chlorite is used and the acidic substance is in a liquid state. In this case, the buffer substance C may be dissolved in an aqueous solution of the acidic substance B in the container 1 and then mixed with the chlorite.

The acidic substance that can be used in this embodiment can be any of the above-mentioned acidic substances. The concentration of the aqueous solution of the acidic substance should be 30% by weight or less.

Example 1
The chlorine dioxide generator X of the present invention was prepared by placing 23.5 wt % sodium chlorite aqueous solution A (43 mL) in container 1 (bottle-shaped, 100 mL volume) and dissolving 7.7 g of tripotassium phosphate (buffer substance C), and placing acidic substance B in a container (acidic substance storage section 13) outside container 1. Acidic substance B was 8.5 g of sodium dihydrogen phosphate (powder).

Sodium dihydrogen phosphate was added to container 1 to bring chlorite aqueous solution A and sodium dihydrogen phosphate into contact. Chlorine dioxide gas generated immediately after mixing chlorite aqueous solution A and sodium dihydrogen phosphate was released to the outside of container 1 via gas release section 11, and chlorine dioxide treatment of the object to be treated was carried out for a predetermined time in the fumigation chamber. Figure 2 is a graph showing the relationship between the amount of chlorine dioxide gas generated and time. As Comparative Example 1, the amount of chlorine dioxide gas generated when buffer substance C was not added is shown.

As a result, in Comparative Example 1, high-concentration chlorine dioxide gas was generated suddenly and in large quantities (up to a maximum of about 3.5 mg per hour) in the early stages of the reaction (up to about 100 hours), and after about 720 hours (about one month), low-concentration chlorine dioxide gas was generated (0.5 mg or less per hour), after which the amount of chlorine dioxide gas generated per hour gradually decreased until about six months had passed.

On the other hand, in Example 1 of the present invention, a low concentration of chlorine dioxide gas (0.3 mg or less per hour) was generated at the beginning of the reaction, and the amount of chlorine dioxide gas generated was maintained at the low concentration at the beginning of the reaction for a long period of time (7200 hours, about 10 months). In addition, at the time when about 2500 hours (about 3.5 months) had passed since the reaction, the amount of chlorine dioxide gas generated per hour exceeded the amount generated per hour in Comparative Example 1. Therefore, in Example 1 of the present invention, it was recognized that it is possible to stably control and generate low concentration chlorine dioxide gas from the beginning of the reaction. In addition, in Example 1 of the present invention, since the concentration of chlorine dioxide gas at the beginning of the reaction can be suppressed, it is possible to dramatically extend the generation period while maintaining the generation concentration of chlorine dioxide gas at the beginning of the reaction, and it is recognized that the life of the chlorine dioxide generator X can be extended.

Example 2
In the chlorine dioxide generator X used in Example 1, the generation of chlorine dioxide gas was investigated when the concentration of the chlorite aqueous solution A was changed variously (3 to 25% by weight) (Invention Examples 2-1 to 2-4). The results are shown in Figure 3. Comparative Examples 2-1 to 2-4 show the generation amount of chlorine dioxide gas when the buffer substance C was not added.

As a result, it was found that in all of the present invention examples 2-1 to 2-4, it was possible to stably control and generate low concentrations of chlorine dioxide gas from the early stage of the reaction compared to the respective comparative examples 2-1 to 2-4. Therefore, it was found that if the concentration of the chlorite aqueous solution A is 3 to 25% by weight, it is possible to suppress the concentration of chlorine dioxide gas at the early stage of the reaction, and to dramatically extend the generation period while maintaining the generation concentration of chlorine dioxide gas at the early stage of the reaction.

Example 3
In the chlorine dioxide generator X used in Example 1, the generation of chlorine dioxide gas was investigated in an embodiment in which the acidic substance B was potassium dihydrogen phosphate (9.6 g) and the buffering substance C was tripotassium phosphate (7.7 g) (Invention Example 3-1), and an embodiment in which the acidic substance B was sodium dihydrogen phosphate (16.5 g) and the buffering substance C was disodium hydrogen phosphate (8.4 g) (Invention Example 3-2). The results are shown in Figure 4. Comparative Examples 3-1 and 3-2 show the amount of chlorine dioxide gas generated when no buffering substance C was added.

As a result, it was found that in each of the present invention examples 3-1 to 3-2, it was possible to stably control and generate low concentrations of chlorine dioxide gas from the early stage of the reaction compared to the respective comparative examples 3-1 to 3-2. Therefore, it was found that by using at least the combination of acidic substance B and buffering substance C as in this example, it is possible to suppress the concentration of chlorine dioxide gas at the early stage of the reaction, and to dramatically extend the generation period while maintaining the generated concentration of chlorine dioxide gas at the early stage of the reaction.

Example 4
In the chlorine dioxide generator X used in Example 1, the generation of chlorine dioxide gas was investigated in an embodiment in which the acidic substance B was acetic acid (2.0 mL) and the buffering substance C was sodium acetate (25.4 g) (Invention Example 4-1), and an embodiment in which the acidic substance B was citric acid (6.8 g) and the buffering substance C was trisodium citrate dihydrate (41.6 g) (Invention Example 4-2). The results are shown in Figure 5. Comparative Examples 4-1 and 4-2 show the amount of chlorine dioxide gas generated when the buffering substance C was not added.

As a result, it was found that in each of the present invention examples 4-1 to 4-2, it was possible to stably control and generate low concentrations of chlorine dioxide gas from the early stage of the reaction, compared to the respective comparative examples 4-1 to 4-2. Therefore, it was found that by using at least the acidic substance B and the buffering substance C in combination as in this example, it is possible to suppress the concentration of chlorine dioxide gas at the early stage of the reaction, and to dramatically extend the generation period while maintaining the generated concentration of chlorine dioxide gas at the early stage of the reaction.

Example 5
In the embodiment of chlorine dioxide generator X (Example 3-1 of the present invention) in which acidic substance B is potassium dihydrogen phosphate and buffer substance C is tripotassium phosphate, the amount of tripotassium phosphate added as buffer substance C was changed to change the pH of the reaction system, and the change in the amount of chlorine dioxide gas generated was examined. The results are shown in Figure 6. As Comparative Example 5, the amount of chlorine dioxide gas generated when buffer substance C was not added is shown.

The pH of the reaction system in Comparative Example 5 was 4.5.
In addition, when 0.5 g of tripotassium phosphate, which is buffer substance C, was added, the pH of the reaction system was 5.0 (Example 5-1 of the invention), when 1.7 g of tripotassium phosphate was added, the pH of the reaction system was 5.5 (Example 5-2 of the invention), when 3.5 g of tripotassium phosphate was added, the pH of the reaction system was 6.0 (Example 5-3 of the invention), and when 7.9 g of tripotassium phosphate was added, the pH of the reaction system was 6.7 to 7.0 (Example 5-4 of the invention).

As a result, it was found that the amount of chlorine dioxide gas generated was 3 mg or less per hour when tripotassium phosphate, which is the buffer substance C, was added, and that in all of the present invention examples 5-1 to 5-4, it was possible to stably control and generate low-concentration chlorine dioxide gas from the beginning of the reaction compared to Comparative Example 5. It was also found that the amount of chlorine dioxide gas generated was suppressed as the pH of the reaction system increased from 5.0 to 6.7 (about 7.0). Therefore, it was found that the amount of chlorine dioxide gas generated could be controlled by adjusting the amount of buffer substance C added to adjust the pH of the reaction system. In particular, it was found that the amount of chlorine dioxide gas generated was 2 mg or less per hour when the pH of the reaction system was adjusted to 5.5 to 7.0, and the amount of chlorine dioxide gas generated was 1 mg or less per hour when the pH of the reaction system was adjusted to 6.0 to 7.0, and that it was found that low-concentration chlorine dioxide gas could be generated more stably and controlled from the beginning of the reaction.

In this example, the results were shown for the case where the acidic substance was a phosphate compound and the buffering substance was a phosphate, but similar results were also obtained when the acidic substance was acetic acid and the buffering substance was acetate, and when the acidic substance was citric acid and the buffering substance was citrate (results not shown).

Example 6
In the chlorine dioxide generator X used in Example 1, tripotassium phosphate, which is the buffering substance C, was dissolved in the aqueous sodium chlorite solution A, and then the acidic substance B was added. In contrast, when the buffering substance C was dissolved in an aqueous solution of the acidic substance B and then mixed with the aqueous sodium chlorite solution A (Example 6-1 of the present invention), and when it was mixed with the solid acidic substance B and then mixed with the aqueous sodium chlorite solution A (Example 6-2 of the present invention), the generation of chlorine dioxide gas was investigated. The results are shown in FIG. 7.

As a result, in any of the cases of Invention Examples 6-1 to 6-2, the behavior of chlorine dioxide gas generation was the same as Invention Example 1, and it was found that low concentrations of chlorine dioxide gas could be stably and controlled to be generated from the early stages of the reaction.

Example 7
In the chlorine dioxide generator X of Example 1, a bottle-shaped container 1 was used, but when the container 1 was made into a pouch shape (bag shape) (Invention Example 7), it was examined how chlorine dioxide gas was generated.

The pouch-shaped container 1 was processed into a rectangular bag (120 mm x 200 mm) when viewed from above (Figure 8). The pouch-shaped container 1 contained a first storage container 10 (100 mm x 150 mm) made of a destructible delamination-type film 10A containing sodium chlorite aqueous solution A and buffer substance C (tripotassium phosphate), and a second storage container 20 (80 mm x 100 mm) made of a water-soluble PVA film containing acidic substance B (sodium dihydrogen phosphate, powder), stacked together. At least one of the front and back surfaces of the container 1 is a gas release portion 11 that is gas permeable and liquid impermeable.

The container 1 was deformed by applying an external force by pressing it with a finger from the outside. At this time, the external force applied to the container 1 was transmitted to the easily destructible first storage container 10, deforming the first storage container 10, and the internal pressure increased, peeling off the desired layer in the interlayer peeling film 10A, making it possible to easily destroy the first storage container 10. The sodium chlorite aqueous solution A released into the inside of the container 1 by destroying the first storage container 10 immediately came into contact with the second storage container 20, and part of the water-soluble second storage container 20 was dissolved. Furthermore, by shaking the container 1 from side to side several times, most of the water-soluble second storage container 20 was dissolved. As a result, the sodium chlorite aqueous solution, tripotassium phosphate, and sodium dihydrogen phosphate were mixed together, and chlorine dioxide gas was generated.

The results are shown in Figure 9. Comparative Example 7 shows the amount of chlorine dioxide gas generated when buffer substance C was not added.

As a result, as in the case of chlorine dioxide generator X in Example 1, in Example 7 of the present invention, it was found that it is possible to stably control and generate low concentrations of chlorine dioxide gas (3 mg or less per hour) from the early stage of the reaction compared to Comparative Example 7, and that it is possible to dramatically extend the generation period while maintaining the generated concentration of chlorine dioxide gas at the early stage of the reaction.

In this example, the results were shown for a case where the acidic substance was a phosphate compound and the buffering substance was a phosphate, but similar results were also obtained when the acidic substance was citric acid and the buffering substance was a citrate (results not shown).

Example 8
In the chlorine dioxide generator X of Example 1, when a gelling agent (water-absorbent resin: AQUALIC (manufactured by Nippon Shokubai Co., Ltd.)) was added together with the acidic substance B, the generation of chlorine dioxide gas was investigated (Invention Example 8). The results are shown in Figure 10. As Comparative Example 8, the generation amount of chlorine dioxide gas when the buffer substance C was not added is shown.

As a result, as in the case of chlorine dioxide generator X in Example 1 of the present invention, it was found that in Example 8 of the present invention, it is possible to stably control the generation of low concentrations of chlorine dioxide gas (0.5 mg or less per hour) from the early stages of the reaction, compared to Comparative Example 8.

The present invention can be used in a chlorine dioxide generator and a chlorine dioxide generation method that generate chlorine dioxide gas in a solvent in a container.

X Chlorine dioxide generator A Chlorite solution B Acidic substance C Buffer substance 1 Container

Claims (17)

A chlorine dioxide generator for generating chlorine dioxide gas by mixing, in a solvent in a container, a chlorite, an acidic substance which reacts with the chlorite to generate chlorine dioxide gas, and a buffer substance which is a salt or a conjugate base of the acidic substance and has a buffering effect on the acidic substance, comprising:
The chlorine dioxide generator is configured to mix the buffering agent with the aqueous chlorite solution prior to mixing the chlorite with the acidic agent. The chlorine dioxide generator according to claim 1, wherein the chlorite is sodium chlorite or potassium chlorite, and the acidic substance is any one of an inorganic acid, an organic acid, and an amphipathic substance. The chlorine dioxide generator according to claim 1 or 2, wherein the acidic substance is a phosphoric acid compound. The chlorine dioxide generator according to any one of claims 1 to 3, wherein the acidic substance is sodium dihydrogen phosphate or potassium dihydrogen phosphate. The chlorine dioxide generator according to claim 3 or 4, wherein the buffering agent is a phosphate. The chlorine dioxide generator according to claim 5, wherein the buffering agent includes at least one of tripotassium phosphate, trisodium phosphate, dipotassium hydrogen phosphate, and disodium hydrogen phosphate. The chlorine dioxide generator according to claim 1 or 2, wherein the acidic substance is acetic acid. The chlorine dioxide generator according to claim 7, wherein the buffering agent is an acetate salt. The chlorine dioxide generator according to claim 7 or 8, wherein the buffering agent contains at least one of potassium acetate and sodium acetate. The chlorine dioxide generator according to claim 1 or 2, wherein the acidic substance is citric acid. The chlorine dioxide generator according to claim 10, wherein the buffering agent is a citrate salt. The chlorine dioxide generator according to claim 10 or 11, wherein the buffering agent contains at least one of potassium citrate and sodium citrate. The chlorine dioxide generator according to any one of claims 1 to 12, wherein the pH of the solvent is 5 to 7. The chlorine dioxide generating apparatus according to any one of claims 1 to 13, wherein the concentration of the chlorite is 3 to 25% by weight. The chlorine dioxide generator according to any one of claims 1 to 14, wherein a gelling agent is added to the solvent in the container. A method for generating chlorine dioxide gas by mixing a chlorite, an acidic substance which reacts with the chlorite to generate chlorine dioxide gas, and a buffer substance which is a salt or a conjugate base of the acidic substance and has a buffering effect on the acidic substance in a solvent in a container, comprising:
The method for generating chlorine dioxide, comprising mixing the buffering substance with the aqueous chlorite solution before mixing the chlorite with the acidic substance. The method for generating chlorine dioxide according to claim 16, wherein the acidic substance and the gelling agent are mixed in a state in which the buffer substance is dissolved in the aqueous chlorite solution.

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