Method and device for producing halogen oxygen-containing acid

Abstract

The present invention provides a method and apparatus for producing an industrially superior halogen-containing oxyacid solution with high efficiency and quality. Specifically, the method and apparatus include the following steps: continuously supplying an organic base solution and a halogen from one end of a reaction tube to the other end, causing a liquid phase and a gas phase to alternate within a transfer passage of the reaction tube; and performing gas-liquid mixing of the organic base solution and the halogen in the liquid phase and / or gas phase.

Description

Technical Field

[0001] The present invention relates to a method for producing a halogen-containing oxygen acid solution, wherein an organic base solution and a halogen are simultaneously supplied to a reaction tube, and the organic base solution and the halogen are mixed and dissolved in the tube in a gas-liquid manner, which is industrially excellent. Background Art

[0002] In the past, various methods have been tried as a method for achieving a target treatment by mixing a gas that exhibits solubility relative to the liquid being the object. For example, a method for obtaining a liquid of a specified concentration by absorbing a gas while circulating the liquid in a tank can be cited (Patent Document 1). It is also known that in order to more efficiently carry out the above method, a method in the form of a tubular device is adopted instead of a tank. For example, the generation of ozone water by blowing ozone into circulating water (Patent Document 2) or the neutralization treatment of alkaline wastewater by blowing carbon dioxide gas into the water (Patent Document 3) can be cited.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-21798

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-221180

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 53-118278 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] The above-mentioned gas dissolution method has no problem when the amount of gas used is within the range of the amount of gas that can be completely dissolved in the liquid. However, as a process for dissolving a large amount of gas in a liquid, any method has disadvantages. That is, when using a gas with low solubility in the liquid as the object, the undissolved gas will leak out of the system, so the gas exceeding the required amount will be wasted. If gases with high environmental loads such as ozone and halogen leak out of the system, leakage measures for harmlessness must be taken. For example, methods for increasing the time and frequency of contact between the gas and the liquid can be cited for the purpose of improving the solubility of the gas in the liquid. However, for this purpose, methods such as increasing the volume of the device or providing a line mixer for the purpose of stirring in the process must be adopted. These methods all make the device larger and the structure more complicated, and the impact on cost and quality also becomes larger.

[0010] Therefore, the present invention focuses on the solubility of halogens in organic alkaline solutions and achieves gas-liquid mixing and dissolution within a pipeline, even without the use of an inline mixer. This method does not increase the size of the apparatus and does not complicate the structure. Furthermore, the present invention provides a method and apparatus for producing an industrially superior halogen-containing oxyacid solution that contains little unreacted halogen, is efficient, and offers high quality.

[0011] Solutions for solving problems

[0012] The present inventors have repeatedly conducted research to achieve the above-mentioned objectives, and as a result, have discovered the following method and its production apparatus, thereby completing the present invention. The method comprises continuously supplying an organic alkaline solution and a halogen from one end of a reaction tube to the other end, and allowing a liquid phase and a gas phase to alternately exist in a transfer passage of the reaction tube. As a result, the organic alkaline solution and the halogen gas-liquid are mixed in the liquid phase and / or the gas phase, thereby industrially producing a halogen-containing oxygen acid more stably and efficiently.

[0013] That is, the configuration of the present invention is as follows.

[0014] Item 1: A method for producing a halogen-containing oxygen acid, comprising the following steps: continuously supplying an organic base solution and a halogen from one end of a reaction tube toward the other end, so that a liquid phase and a gas phase alternately exist in a transfer passage of the reaction tube, and performing gas-liquid mixing of the organic base solution and the halogen in the liquid phase and / or the gas phase.

[0015] Item 2: The method for producing a halogen oxyacid according to Item 1, wherein a ratio of a volume flow rate of the halogen supplied to the reaction tube to a volume flow rate of the organic alkaline solution is 1 to 50.

[0016] Item 3: The method for producing a halogen oxyacid according to Item 1 or 2, wherein the reaction tube extends in the axial direction while rotating around a direction extending from one end to the other end thereof as an axis.

[0017] Item 4: The method for producing a halogen oxyacid according to any one of Items 1 to 3, wherein the reaction tube is arranged so as to extend in a substantially horizontal direction.

[0018] Item 5: The method for producing a halogen-containing oxyacid according to any one of Items 1 to 4, wherein the reaction tube is formed in a spiral shape with a direction extending from one end to the other end thereof as an axis and the axis serving as a spiral axis.

[0019] Item 6: The method for producing a halogen oxyacid according to any one of Items 1 to 5, wherein the reaction tube is a reaction tube made of a fluororesin.

[0020] Item 7: The method for producing a halogen oxyacid according to any one of Items 1 to 6, wherein the average inner diameter of the reaction tube is 5 mm or more.

[0021] Item 8: A device for producing a halogen-containing oxygen acid, comprising a reaction tube, wherein the reaction tube extends in the axial direction while rotating around the axis extending from one end thereof toward the other end, the reaction tube being configured so that the axis extends in a substantially horizontal direction. The device for producing a halogen-containing oxygen acid has the following structure: an organic alkaline solution and a halogen are continuously supplied from the one end toward the other end, so that a liquid phase and a gas phase alternately exist in a transfer passage of the reaction tube, and the organic alkaline solution and the halogen are mixed as a gas and a liquid in the liquid phase and / or the gas phase.

[0022] Item 9: The apparatus for producing a halogen oxyacid according to Item 8, further comprising means for supplying the organic alkaline solution and the halogen to the reaction tube at a ratio of 1 to 50 of the volume flow rate of the halogen to the volume flow rate of the organic alkaline solution.

[0023] Item 10: The apparatus for producing a halogen oxyacid according to Item 8 or 9, wherein the reaction tube is a spirally formed reaction tube, and is arranged so that the spiral axis of the reaction tube extends in a substantially horizontal direction.

[0024] Item 11: The apparatus for producing a halogen oxyacid according to any one of Items 8 to 10, wherein the reaction tube is a reaction tube made of a fluororesin.

[0025] Item 12: The apparatus for producing a halogen oxyacid according to any one of Items 8 to 11, wherein the average inner diameter of the reaction tube is 5 mm or more.

[0026] Item 13: The apparatus for producing a halogen oxyacid according to any one of Items 8 to 12, wherein the reaction tube is configured so that the liquid residence time of the organic alkaline solution is 5 seconds to 30 minutes.

[0027] Effects of the Invention

[0028] An organic alkaline solution and a halogen are continuously supplied from one end of the reaction tube, and the reaction solution containing the generated halogen oxyacid is continuously taken out from the other end of the reaction tube. By frequently performing gas-liquid mixing in the mixed solution in the reaction tube, under steady state, the component concentration, pH, etc. of the organic alkaline solution as a raw material and the generated halogen oxyacid are maintained constant. Thus, side reactions, etc. are suppressed, and a reaction solution with good storage stability is obtained, and unreacted halogen decreases, thereby suppressing the waste of raw materials. In addition, the effect of shortening the time from the start of the reaction to the reaction solution obtaining a stable composition is also obtained, therefore, the generation amount of waste liquid can also be reduced, therefore, halogen oxyacid is efficiently and stably obtained. In addition, by the continuous supply of raw materials and the continuous taking out of reaction product, a large number of industrial manufacturing can be coped with. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram showing one aspect of a production apparatus according to an embodiment of the present invention.

[0030] Figure 2 This is a graph showing the relationship between the operating time and the effective chlorine concentration when the production methods according to the embodiment of the present invention and the comparative example are used.

[0031] Figure 3 This is a schematic diagram showing the existence of the gas phase and liquid phase in the reaction tube. Figure 3 (a) shows the state in which the liquid phase and the gas phase alternately repeat in the reaction tube. Figure 3 (b) shows a state where the liquid phase and the gas phase do not alternate in the reaction tube. DETAILED DESCRIPTION

[0032] <Method for producing halogen-containing oxygen acid>

[0033] (Reaction format, reaction tube)

[0034] Next, one of the characteristics of this embodiment is that an organic alkaline solution and a halogen are continuously supplied, and the generated reaction solution containing a halogen-containing oxyacid is continuously taken out. It should be noted that the continuous removal of the reaction solution containing the halogen-containing oxyacid is preferably a scheme in which an amount corresponding to the amount of the continuously supplied organic alkaline solution and the halogen is taken out. The corresponding amount refers to an amount that is the same as or proportional to the total amount of the supplied organic alkaline solution and the halogen (the total amount of the organic base and the halogen > the amount taken out: all are by volume). The same is also true in the manufacturing device described later.

[0035] In the present invention, it is preferable to keep constant the components in the reaction tube in a steady state, namely, the amount of the organic alkaline solution, the amount of the generated halogen oxyacid, and the pH of the reaction solution taken out of the reaction tube, and to adjust the supply amount with high precision.

[0036] The conventional semi-batch reaction method is a process in which a halogen is gradually added to an organic alkaline solution already loaded into a reactor. This results in a tendency for the pH of the reaction solution to be high at the start of the reaction, making it easy for the halogen-containing oxyacid to decompose at high pH. Furthermore, the halogen-containing oxyacid generated in the high pH region generates decomposition products resulting from the decomposition of the halogen-containing oxyacid, thus presenting problems with storage stability. On the other hand, if the organic alkaline solution and halogen are continuously supplied and the reaction solution is continuously withdrawn, the reaction solution in the reaction tube reaches a steady state after a certain period of time, maintaining a constant pH. Consequently, the decomposition of the halogen-containing oxyacid after reaching a steady state is suppressed.

[0037] According to the production method of the embodiment of the present invention, it is possible to prevent the pH of the reaction solution from being maintained at a high state. It should be noted that, unless otherwise specified, the pH in the present invention refers to a value at 25°C.

[0038] In this way, by continuously supplying an organic alkaline solution and a halogen and continuously taking out the generated reaction solution containing a halogen-containing oxyacid, the residence time of the high pH that causes the maximum side reaction of this reaction can be shortened. In the case where chlorine gas or chlorine is used as an example of the halogen used, the result is that the chlorine yield can be maintained high. The chlorine yield mentioned here can be calculated by the ratio (%) of the number of moles of hypochlorite ions generated relative to the number of moles of chlorine molecules supplied to the organic alkaline solution. When the chlorine added to the organic alkaline solution reacts in total (no decomposition occurs), the chlorine yield is 100%. When the hypochlorite ions decompose during the reaction, the chlorine yield decreases.

[0039] It should be noted that, in the present invention, a reaction tube refers to an apparatus for performing a chemical reaction during the production process of a chemical substance. The organic base solution and the halogen are preferably continuously supplied to the reaction tube at a constant ratio. Supplying at a constant ratio means that the supply rate is constant. Furthermore, the continuous removal of the reaction solution may be initiated simultaneously with the start of the production method according to an embodiment of the present invention, or may be performed after the pH of the reaction solution removed from the reaction tube reaches a constant value.

[0040] Furthermore, it is preferable to uniformize the components and pH of the reaction solution within the reaction tube. The pH of the reaction solution of the organic alkaline solution and the halogen supplied to the reaction tube is preferably 10.5 to 14.5. Furthermore, the pH of the reaction solution of the organic alkaline solution and the halogen is more preferably 10.5 to 13.8. Furthermore, the pH of the reaction solution of the organic alkaline solution and the halogen is even more preferably 12.0 to 13.8. Furthermore, the pH of the reaction solution removed from the reaction tube is preferably 12.0 to 13.8.

[0041] In order to mix the organic alkali solution with the halogen in the reaction tube, it is preferred that the liquid phase and the gas phase are alternately and repeatedly present in the transfer direction in the transfer passage. Thus, even if a pipeline mixer for the purpose of mixing operation is not provided in the tube, the liquid can be uniformly stirred and mixed. A pipeline mixer (stirring mixer) is usually used as a stirring method for uniformly stirring the fluid passing through the tube. As for pipeline mixers, the main ones include: a pipeline mixer that drives the stirring blades provided in the space inside the tube to mix the fluid; or a tubular static mixer (inline mixer, static mixing agitator) that does not have a driving part and uses the fluid to mix by passing through a component fixed in the space inside the tube. These pipeline mixers are used for efficient fluid mixing, but when it is necessary to generate a high-purity liquid such as a semiconductor liquid that is not contaminated by particles, metal components, etc., the contamination from the contact part will greatly affect the quality, so it is sometimes difficult to set a pipeline mixer in the tube. In a reaction tube without an inline mixer, the mixing property of gas and liquid is reduced, resulting in uneven concentration of the reaction liquid and short pass of the gas phase in the tube, which is disadvantageous as an industrial production method.

[0042] In the transfer passage of the reaction tube, the state in which the liquid phase and the gas phase do not alternate and repeatedly exist in the transfer direction will lead to a reduction in the number of gas-liquid contacts and the frequency, so the gas-liquid mixed state in the tube deteriorates. In this case, in order to stabilize the liquid composition, it is necessary to add a process to improve the mixed state of gas and liquid. In the case where a pipeline mixer is not provided in the tube, the length of the reaction tube must be extended. In addition to increasing equipment costs, extending the reaction tube will also lead to an increase in the amount of waste liquid generated when replacing in the reaction tube. Therefore, in terms of equipment and raw materials, it is disadvantageous in terms of cost. As the present invention makes the liquid phase and the gas phase alternate and repeatedly exist in the transfer passage of the reaction tube, it will help to subdivide the number of gas-liquid contacts and the frequency in the reaction tube, and form a state close to simulating piston flow (plug flow) in the reaction tube, thereby continuously obtaining a reaction solution of the same concentration. Thus, the organic alkaline solution and the halogen can be evenly mixed in the reaction tube without the need to provide a pipeline mixer.

[0043] Due to these effects, the present invention is also characterized in that, only by the reaction solution replacing once in the reaction tube, the liquid of stable composition can be continuously obtained. That is, the volume required for switching the state in the tube from the organic alkaline solution before the reaction to the liquid after the reaction is determined by the length from the entrance to the outlet of the reaction tube. Thus, the replacement operation in the tube carried out by the reaction solution can be optimized, and the amount of unnecessary waste liquid can be suppressed to a minimum from the start of the reaction to the stable liquid composition, so there is a favorable effect in industry.

[0044] The simplest way to alternately arrange the liquid phase and the gas phase in the reaction tube is to set the diameter of the supply pipe for the gas phase and the liquid phase to be the same as or smaller than the diameter of the reaction tube. In this way, a gas phase and a liquid phase with the same diameter as the reaction tube can be alternately formed on the inlet side of the reaction tube where the gas and liquid are in contact. However, when the liquid-gas ratio (the value obtained by dividing the volume flow rate of the liquid phase supplied to the reaction tube per unit time by the volume flow rate of the gas phase supplied to the reaction tube per unit time) becomes greater than 1, the halogen present in the gas phase will not be fully dissolved in the liquid phase, but will be discharged from the outlet side of the reaction tube as undissolved halogen. As a countermeasure, a method of extending the time until the halogen dissolves by extending the length of the reaction tube can be cited, but as a simpler method to promote the dissolution of the halogen in the reaction tube, it is preferred to extend the tube while rotating relative to the axial direction of the extension of the reaction tube. That is, it is preferred that the direction extending from one end of the reaction tube to the other end is the axis, and the reaction tube is extended in the axial direction while rotating around the axis. The axial direction mentioned here preferably extends in the horizontal direction rather than the vertical direction, but this does not limit the axis to the horizontal direction. The direction of the extending axis may be in any inclination. Among the inclination axes, it is more preferable to extend the reaction tube in a substantially horizontal direction.

[0045] The required rotation diameter for axial rotation can be determined based on the length of the reaction tube and the strength of the material used. For example, it can be between 30 mm and 3000 mm, preferably between 60 mm and 600 mm. By rotating the reaction tube once or more, the gas-liquid mixing efficiency is improved. The reaction tube is essentially divided into two phases: a gas phase that rises due to the buoyancy generated by the gas volume, and a liquid phase that descends due to gravity. However, by rotating the reaction tube, for example, the gas phase always comes into contact with the liquid phase located vertically below. Therefore, a higher rotation speed of the reaction tube improves gas-liquid mixing and prevents short-circuiting of the gas phase. It should be noted that the gas phase may not exist in the vertically lower portion of the reaction tube. Furthermore, the lengths of the gas and liquid phases in the reaction tube may vary in the transfer direction. There is no upper limit to the number of rotations of the rotating reaction tube, but it is preferably two or more, more preferably five or more, and even more preferably ten or more. On the other hand, the upper limit of the number of rotations is usually 50 or less. In addition, the average inner diameter of the reaction tube has no upper limit, but is preferably 5 mm or more, more preferably 5 mm or more and 500 mm or less, and further preferably 10 mm or more and 100 mm or less.

[0046] The appearance of the device that meets these device structures is most preferably in the form of a reaction tube formed in a spiral shape along the axial direction, but the form of the reaction tube is not limited to this. It is also preferred that the reaction tube is alternately bent along the axial direction or processed into a wavy shape along the axial direction.

[0047] The inner diameter and length of a reaction tube affect the volume of the reaction solution and are therefore important factors for industrial mass production of the reaction solution. Industrial mass production herein refers to reducing the amount of waste liquid generated to efficiently and continuously produce the target reaction solution. Preferably, the production rate is at least one multiple, more preferably at least five times, and even more preferably at least 100 times the volume of the liquid in the tube per hour.

[0048] The inert gas can also be supplied to the reaction tube together with the organic base solution and the halogen that are continuously supplied to the reaction tube. The supply of inert gas is useful in terms of playing the role of making the liquid phase and the gas phase alternately exist repeatedly in the reaction tube, and preventing the backflow of the liquid phase and the gas phase in the system. Inert shielding gas refers to air, nitrogen, argon, helium and other gases that are irrelevant to the reaction and stable, and is preferably air from the cost aspect. However, the carbon dioxide contained in the air can dissolve in the reaction solution and cause the reduction of pH, or may become the reason for generating impurities by reaction, so it is more preferred to use an inert shielding gas purified to high purity, wherein, nitrogen is preferably used from the cost aspect.

[0049] The volume in the reaction tube can be changed according to the supply rate of the organic alkali solution used. When the value obtained by dividing the volume in the reaction tube by the capacity of the organic alkali solution supplied to the reaction tube per unit time is defined as the liquid residence time, the liquid residence time of the organic alkali solution in the reaction tube is preferably a reaction tube of 5 seconds to 30 minutes, more preferably 10 seconds to 5 minutes. In the present invention, only by replacing the reaction solution once in the reaction tube, a liquid of a stable composition is continuously obtained. This means that the time required to obtain a stable liquid composition is directly related to the liquid residence time. When the reaction starts, when the mixed state in the tube is insufficient, in order to obtain a liquid of a stable composition, at least 3 times or more of the liquid residence time is required.

[0050] Furthermore, the supply rate of the supplied halogen, expressed as the ratio of the volume flow rate of the halogen supplied to the reaction tube to the volume flow rate of the organic alkaline solution, is preferably 1 to 50, and more preferably 10 to 30. Within this range, even when the shape of the reaction tube is not the shape in which the tube is extended while being rotated about the axial direction of the elongation of the reaction tube as described above, it can contribute to the realization of a configuration in which the gas phase and the liquid phase alternate in the direction of transfer into the reaction tube.

[0051] In addition, when the halogen is a gas, the volume flow rate of the halogen supplied to the reaction tube is calculated based on 0° C. and 1 atm.

[0052] By dissolving the halogen supplied to the reaction tube in the organic alkaline solution in the tube, the dissolved gas in the solution can be degassed. That is, by generating heat of solution by the halogen in the reaction tube and raising the liquid temperature of the solution, the dissolved gas that cannot be completely dissolved in the liquid moves out of the liquid, thereby achieving a degassing effect. The greater the liquid-to-gas ratio, the greater the heat of solution and the supply amount of the halogen, and therefore the more easily degassed effect can be achieved. It should be noted that the dissolved gas may include nitrogen, oxygen, carbon dioxide, etc., but the dissolved gas to be degassed is not limited thereto.

[0053] In addition, there are also cylindrical reaction tubes (cylindrical reaction tubes), but these are in a state where only one of the openings of the reaction tube is blocked. Cylindrical reaction tubes are structurally unsuitable for quickly obtaining a liquid with a stable composition, which is the effect of the present invention. Specifically, a separate portion is required to circulate the liquid through the reaction tube, and it is difficult to replace the liquid within the reaction tube, making it difficult to stabilize the liquid. Therefore, the liquid before stabilization must be discarded. The present invention, which achieves stabilization through a single liquid replacement, also reduces the amount of waste liquid generated, thus being economically advantageous.

[0054] (Organic alkaline solution)

[0055] The organic alkali solution supplied to the reaction tube may be any of an aqueous solution obtained by dissolving an organic base in water or a solution obtained by dissolving an organic base in a non-aqueous solvent. The organic alkali solution can be obtained by dissolving the organic base in water or a non-aqueous solvent, diluting a commercially available organic alkali solution to a desired concentration, etc. Among these water or non-aqueous solvents, water is preferably used because it is easily available industrially and can produce a high-purity organic alkali solution. As non-aqueous solvents, known organic solvents that can dissolve organic bases can be listed. Specifically, alcohols and glycols can be listed, with methanol and propylene glycol being particularly preferred. The concentration of the organic alkali solution is not particularly limited, but if the concentration of the organic base becomes high, salts will precipitate and become solids. Therefore, the concentration of the organic base in the organic alkali solution is preferably 0.01 to 30% by mass, more preferably 0.05 to 27.5% by mass, and even more preferably 0.1 to 25% by mass.

[0056] As the solvent for the organic alkali solution, an aqueous solution having only water as a solvent can be used, or it can be mixed with an organic solvent and used in the form of a non-aqueous solution, or the aqueous solution can be mixed with an organic solvent. The solvent can be appropriately changed correspondingly to the purpose of the solution comprising the halogen oxyacid. For example, when the cleaning object is set to ruthenium, the solvent can be fully cleaned by using only water, so it can be used in the form of an aqueous solution of an organic base.

[0057] In the present embodiment, the organic alkali solution is preferably a solution of onium hydroxide. As an example of onium hydroxide, one or more of the group consisting of ammonium hydroxide, phosphonium hydroxide, sulfonium hydroxide, iminium hydroxide (iminium hydroxide) and diazonium hydroxide containing multiple bonds can be listed. Among them, more preferably a solution of ammonium hydroxide in which a relatively stable compound exists in large quantities. In addition, the solution of the above-mentioned onium hydroxide is preferably an aqueous solution of onium hydroxide. In addition, the solution of the above-mentioned ammonium hydroxide is preferably a tetraalkylammonium hydroxide solution.

[0058] The tetraalkylammonium hydroxide solution is preferably a solution of tetraalkylammonium hydroxide in which the alkyl groups independently have 1 to 10 carbon atoms, and more preferably a solution of tetraalkylammonium hydroxide in which the carbon atoms independently have 1 to 5 carbon atoms. Specific examples of tetraalkylammonium hydroxides include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and choline. These tetraalkylammonium hydroxides may be used alone or in combination of two or more. Furthermore, the four alkyl groups in the tetraalkylammonium hydroxide may have the same or different carbon atoms.

[0059] It should be noted that the various conditions described above and below, such as the concentration range of the organic base in the organic base solution supplied to the reactor, the pH range of the organic base solution, the concentration range of the organic base in the reaction solution, etc., can be applied when any specific example of the above-mentioned organic base is used.

[0060] The organic alkaline solution may also contain chemical species other than the organic base. Examples of such chemical species include halides and halogen-containing organic substances. More specifically, tetraalkylammonium halides such as tetramethylammonium bromide may be exemplified, but are not limited thereto. Furthermore, the organic alkaline solution may be prepared by reusing the reaction solution obtained by reacting the halogen once with the halogen, or by supplying the same halogen or another halogen to the solution.

[0061] (Step of mixing an organic base solution with a halogen gas-liquid to produce a reaction solution containing a halogen oxyacid)

[0062] In the process of mixing an organic alkaline solution with a halogen gas-liquid and reacting them to manufacture a reaction solution comprising a halogen oxyacid, there is a tendency that the pH of the reaction solution comprising the halogen oxyacid produced in the reaction tube decreases. In the present embodiment, the lower limit of the pH of the organic alkaline solution that becomes the raw material is 10.5 or more, preferably 11.0 or more, more preferably 11.5 or more, and particularly preferably more than 12.0. The upper limit of the pH of the organic alkaline solution is determined according to the concentration of the organic base. As an example of the upper limit of the pH of the organic alkaline solution, 14.5 or less can be cited.

[0063] Furthermore, in the organic alkaline solution used in this embodiment, the metal content, specifically sodium, potassium, aluminum, magnesium, iron, nickel, copper, silver, cadmium, and lead, is preferably 0.01 ppb or more and 20 ppb or less. It should be noted that, while the metal content in the organic alkaline solution used can be less than 0.01 ppb, obtaining such an organic alkaline solution is inherently difficult.

[0064] Therefore, by using an organic alkaline solution having the above-mentioned metal content within the above-mentioned range, the organic alkaline solution itself can be easily obtained, and the metal impurities can be easily removed / reduced during and after the production of the reaction solution containing the halogen oxyacid.

[0065] Furthermore, the metals mentioned above are eluted from the areas in contact with the organic alkaline solution within the reaction tube, so a reaction tube with a small contact area is preferred. Specifically, a reaction tube with a small volume is important for reducing impurities and is also very effective from the perspective of quality control. There is no upper limit to the range of the contact area of the reaction tube, but a preferred contact area is 0.01 m 2 More than 10m 2 Below, more preferably 0.1m 2 Above and 1.0m 2 the following.

[0066] Commercially available organic alkaline solutions can be used as the above-mentioned organic alkaline solutions. Among them, organic alkaline solutions that have been highly purified by electrolysis and / or by contact with ion exchange resins, etc., and are used as photoresist developers for semiconductor devices, can be appropriately utilized. Furthermore, these commercially available products can be diluted with a solvent free of metal impurities, such as ultrapure water, before use.

[0067] In the production method according to the embodiment of the present invention, when the volume of the reaction tube is 1 L, the supply rate of the organic alkaline solution is preferably 33 mL / min to 12 L / min, more preferably 0.2 L / min to 6 L / min.

[0068] (Reaction by contacting an organic base solution with a halogen)

[0069] For example, when tetraalkylammonium hydroxide is used as the organic base, the hydroxide ions of the tetraalkylammonium hydroxide are replaced with hypohalite ions generated from the halogen by contacting and reacting the solution with the halogen, thereby generating a tetraalkylammonium hypohalite solution.

[0070] In the present embodiment, the halogen used is not particularly limited and commercially available products can be used. Specific examples of halogen include chlorine, bromine, iodine, hypochlorous acid, hypobromous acid, hypoiodous acid, chlorous acid, bromous acid, iodous acid, chloric acid, bromic acid, or iodic acid. When chlorine or bromine is used, their gases can be used. Among these, chlorine is preferably used.

[0071] Next, in this embodiment, as an example of an embodiment of the present invention, a method of contacting a tetraalkylammonium hydroxide solution as an organic alkaline solution and chlorine gas as a halogen will be described. In the following description, unless otherwise specified, the use of a tetraalkylammonium hydroxide solution as an organic alkaline solution and chlorine gas as a halogen may be assumed, but this is merely an example.

[0072] (pH of the liquid phase during reaction)

[0073] The pH of the liquid phase during the reaction of the present embodiment is preferably more than 10.5. It should be noted that, in the present embodiment, the liquid phase refers to the part occupied by the reaction solution generated by mixing tetraalkylammonium hydroxide solution and chlorine gas during the reaction. The upper limit of the pH of the liquid phase is not particularly limited, but if the pH in the reaction is too high, then after the reaction is completed, when the same pH is stored for a long time, hypochlorite ion is decomposed, and sometimes available chlorine concentration can be reduced. Therefore, the pH of the liquid phase during the reaction is preferably more than 10.5 and less than 14.5, more preferably more than 10.5 and less than 13.8, further preferably more than 12 and less than 13.8. If pH is above-mentioned scope, then during the storage period of the tetraalkylammonium hypochlorite solution obtained, the decomposition of hypochlorite ion is suppressed, and storage stability improves.

[0074] (Reaction temperature)

[0075] The reaction temperature in the production method of this embodiment is preferably in the range of -35°C to 45°C, more preferably -15°C to 40°C, and even more preferably -5°C to 35°C. If the reaction temperature is within the above range, the organic alkali hydroxide solution reacts fully with the halogen, and the halogen-containing oxyacid can be obtained in high yield. It should be noted that when the reaction temperature is lower than -35°C, the organic base begins to solidify, and the reaction with the halogen becomes insufficient. On the other hand, when the reaction temperature exceeds 45°C, the halogen-containing oxyacid ions generated in the halogen-containing oxyacid solution decompose due to heat. In particular, when the pH during the reaction is 13.8 or higher, the decomposition of the halogen-containing oxyacid becomes significant as the reaction temperature increases. The yield of the halogen-containing oxyacid can be evaluated by the chlorine yield. As described above, according to the production method of this embodiment, a halogen-containing oxyacid with excellent storage stability can be produced, for example, which can maintain sufficient cleaning and removal power even after 10 days after production. This demonstrates that the halogen oxyacid obtained by the production method of the present embodiment has excellent storage stability and can be suitably used in the production process of semiconductor devices.

[0076] (Material of the inner surface of the reaction tube)

[0077] In this embodiment, the organic alkaline solution is brought into contact with the chlorine gas in a reaction tube to produce the halogen oxyacid. First, a predetermined amount of the organic alkaline solution is introduced into the reaction tube, and then the chlorine gas is introduced so as to contact the organic alkaline solution.

[0078] Furthermore, in the present embodiment, the surface in contact with the organic alkaline solution in the reaction tube (hereinafter sometimes referred to as the "inner surface of the reaction tube") is formed of a general-purpose borosilicate glass or organic polymer material. According to the research of the present inventors, if a general-purpose borosilicate glass (hereinafter referred to as glass) reaction tube is used as the reaction tube, the metal components contained in the glass, such as sodium, potassium, and aluminum, will slightly dissolve in the organic alkaline solution. This is believed to be because the organic alkaline solution used as a raw material exhibits alkalinity. Therefore, it is more preferred that the inner surface of the reaction tube be formed of an organic polymer material to further reduce the mixing of impurities containing the above-mentioned metals (metal impurities).

[0079] In addition, the reaction is preferably carried out under a light-shielding environment. Specifically, the reaction tube is preferably light-shielded in the reaction tube. The above-mentioned chlorine gas present in the reaction tube is sometimes excited by light and produces chlorine free radicals. When chlorine free radicals are produced, the organic alkaline solution present in the reaction tube or the halogen oxyacid generated by the reaction may sometimes be affected and decomposed. In addition, the above-mentioned halogen oxyacid itself may sometimes decompose due to light. A preferred embodiment is to shield the reaction tube, incidental piping, etc. from light.

[0080] In this embodiment, when an organic solvent is used as the solvent, the reaction apparatus is preferably made into an explosion-proof structure. Therefore, in order to adopt a simple apparatus structure, the organic alkaline solution is preferably made of water as the solvent.

[0081] In this embodiment, the organic polymer material used for the inner surface of the reaction tube may be vinyl chloride resin (soft / hard vinyl chloride resin), nylon resin, silicone resin, polyolefin resin (polyethylene, polypropylene), fluororesin, etc. Among them, fluororesin is preferred in consideration of ease of molding, solvent resistance, and low elution of impurities.

[0082] As the fluororesin, there is no particular limitation as long as it is a resin (polymer) containing fluorine atoms, and known fluororesins can be used. For example, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, chlorotrifluoroethylene-ethylene copolymer, and cyclized polymers of perfluoro(butylene vinyl ether) can be listed. Among them, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer is preferably used due to the ease of obtaining the reaction tube itself and productivity.

[0083] In this embodiment, as methods for forming the inner surface of the reaction tube with an organic polymer material, there are: a method of forming the entire reaction tube with an organic polymer material; a method of covering only the inner surface of a glass / stainless steel reaction tube with an organic polymer material, and the like.

[0084] In addition, to prevent the metal components from being eluted from the organic polymer material, it may be cleaned before use. Specifically, it is preferably thoroughly cleaned with an acid such as high-purity nitric acid or hydrochloric acid (for example, by immersing in a solution with an acid concentration of 1 mol / L for 12 hours for cleaning), and further cleaned with ultrapure water or the like. In addition, for a stable reaction, before reacting the organic base solution with chlorine gas, the inner surface of the reactor formed by the above-mentioned organic polymer material is preferably cleaned using the above-mentioned method.

[0085] In this embodiment, if the surface in the reaction tube that contacts the organic alkaline solution is formed of an organic polymer material, the other parts may be made of glass, stainless steel, or passivated stainless steel.

[0086] In the present embodiment, as long as above-mentioned organic alkali solution is contacted with chlorine in reaction tube, the scope of reaction temperature at this moment is not particularly limited, but is preferably set to be identical with above-mentioned reaction temperature.In addition, if there is carbon dioxide in the reaction system, then there is the tendency that the pH of the halogen oxyacid solution obtained reduces.Therefore, if considering stable manufacturing, then preferably make the reaction system free of carbon dioxide.Specifically, preferably use organic alkali solution, chlorine etc. that carbon dioxide amount is reduced.And, preferably implement reaction in the presence of the inert gas that carbon dioxide amount is reduced (for example, in the presence of nitrogen).By reacting under such conditions, the pH of the halogen oxyacid solution obtained can be suppressed to reduce, and therefore, storage stability improves.

[0087] <Halogen oxygen acid production equipment>

[0088] Next, an embodiment of a halogen-containing oxyacid production apparatus will be described. The above-described production method can be implemented using the production apparatus of this embodiment. It should be noted that, as an example of the production apparatus of this embodiment, a case where a tetraalkylammonium hydroxide solution is used as the organic base and chlorine gas is used as the halogen is described. It should be noted that the conditions such as the type and concentration of the organic base and halogen supplied as raw materials can be the same as those described in the above-described halogen-containing oxyacid production method.

[0089] The manufacturing apparatus of this embodiment includes a reaction tube, which extends in the axial direction while rotating around an axis extending from one end of the reaction tube toward the other end. The reaction tube is configured so that the axis extends in a substantially horizontal direction. The manufacturing apparatus of the halogen-containing oxygen acid has the following structure: an organic alkaline solution and a halogen are continuously supplied from the one end toward the other end, so that a liquid phase and a gas phase alternately exist in a transfer passage of the reaction tube, and the organic alkaline solution and the halogen are mixed in a gas-liquid state in the liquid phase and / or the gas phase.

[0090] Figure 1 A schematic diagram of a production apparatus according to this embodiment is shown. Figure 1 The described production apparatus comprises: a reaction tube 1; a pipe 2 for supplying a tetraalkylammonium hydroxide solution, serving as an organic base supply unit for supplying the solution to the reaction tube; a pipe valve 5 for performing and stopping the supply of the solution; a pipe 3 for supplying a chlorine gas, serving as a halogen supply unit; a pipe valve 6 for performing and stopping the supply of the chlorine gas; and a reaction liquid removal pipe 8, serving as a reaction liquid removal unit for removing the reaction liquid from the reaction tube to the outside.

[0091] In reaction tube 1, a tetraalkylammonium hydroxide solution is supplied from tetraalkylammonium hydroxide solution supply pipe 2, and chlorine gas is supplied from chlorine gas supply pipe 3, both of which are continuously supplied. The supply and stop of chlorine gas are controlled by pipe valve 6. Furthermore, the generated reaction liquid is continuously withdrawn from reaction liquid withdrawal pipe 8.

[0092] The conditions described in the above-mentioned production method can be used for the areas where the tetraalkylammonium hydroxide solution flows and contacts. The inner surface of the reaction tube 1 is preferably formed from an organic polymer material. Specifically, the reaction tube is preferably a reaction tube containing a fluororesin, and preferably, the entirety of the reaction tube 1 or at least its inner surface is composed of a fluororesin. The fluororesin can be any of the materials exemplified in the "Material for the Inner Surface of the Reaction Tube" above.

[0093] The chlorine supply pipe 3, which serves as the chlorine gas supply unit, preferably has the same diameter as the reaction tube 1. However, to facilitate dispersion of the chlorine gas in the liquid phase, the diameter of the chlorine gas supply pipe 3 may be smaller than that of the reaction tube 1. The blowing rate of the chlorine gas is preferably 0.1 m / sec or higher and 10 m / sec or lower, calculated at 0°C and 1 atm.

[0094] The volume of the reaction tube can be varied depending on the feed rate of the tetraalkylammonium hydroxide solution used. When the liquid residence time is defined as the value obtained by dividing the volume of the reaction tube by the volume of the tetraalkylammonium hydroxide solution supplied to the reaction tube per unit time, a reaction tube volume of 5 seconds to 30 minutes is preferred as the liquid residence time of the tetraalkylammonium hydroxide solution, and more preferably 10 seconds to 5 minutes. Furthermore, the feed rate of the halogen supplied, calculated as the ratio of the volume flow rate of the halogen supplied to the reaction tube to the volume flow rate of the organic base solution, is preferably 1 to 50, and more preferably 10 to 30.

[0095] The reaction tube preferably extends in the axial direction while rotating around the axis. In addition, the reaction tube is preferably configured to extend in a substantially horizontal direction, and the reaction tube is a spirally formed reaction tube, and more preferably, the spiral axis of the reaction tube is extended in a substantially horizontal direction. The rotation diameter (inner diameter of the spiral circle) required for rotation can be determined according to the length of the reaction tube and the strength of the material used. For example, it can be listed as 30 mm or more and 3000 mm or less, preferably 60 mm or more and 600 mm or less. The reaction tube is rotated more than one turn to obtain an effect of improving gas-liquid mixing. Therefore, there is no upper limit to the number of rotations of the rotating reaction tube, but it is preferably formed as a device of at least 2 turns, more preferably 5 turns or more, and more preferably 10 turns or more. On the other hand, the upper limit of the number of rotations is usually 50 turns or less. The higher the number of rotations of the reaction tube, the more advantageous it is for gas-liquid mixing. The range of the average inner diameter of the reaction tube has no upper limit, but is preferably 5 mm or more, more preferably 5 mm or more and 500 mm or less, and even more preferably 10 mm or more and 100 mm or less.

[0096] In order to adjust the concentration of the gas component supplied to the reaction tube 1, the reaction tube 1 may also be provided with a nitrogen supply pipe 4 as a unit for supplying nitrogen into the reaction tube 1. In addition, a pipe valve 7 may also be provided to perform nitrogen supply and stop operations. The reaction of the tetraalkylammonium hydroxide solution and chlorine is an exothermic reaction. In the manufacturing apparatus of this embodiment, the temperature in the reaction tube 1 can be measured using, for example, a reaction liquid temperature measuring device 9 as a temperature measuring unit in the reaction tube 1. In addition, the manufacturing apparatus of this embodiment may also be provided with a reaction tube temperature control jacket 10 as a reaction temperature control unit in the reaction tube, specifically a unit for removing heat from the reaction tube. Heat removal can be performed by the reaction tube temperature control jacket 10. In order to perform the reaction under light-shielding conditions, the manufacturing apparatus of this embodiment may also be provided with a light-shielding unit.

[0097] In addition, the manufacturing apparatus of this embodiment may also be equipped with a reaction liquid pH measuring device 11 configured on the reaction liquid extraction pipe 8 as a pH measuring unit for the reaction liquid. In addition, the measuring liquid used for pH measurement may cause contamination of the reaction liquid, so it is more preferable to circulate the pipe branch in advance. By using the reaction liquid pH measuring device 11, the pH of the reaction liquid after the reaction can be measured. The manufacturing apparatus of this embodiment preferably has at least one of the reaction temperature measuring unit, the reaction temperature control unit, and the pH measuring unit in the above-mentioned reactor, more preferably has two, and even more preferably has all.

[0098] In order to avoid unreacted chlorine etc. being discharged into outside the system, also can after the taking-out piping 8 of reaction solution, remove the harm unit is set, specifically sodium hydroxide remove the harm device 13 is set.As the formation of sodium hydroxide remove the harm device 13, for example, can use following formation: in the reaction solution storage tank 12 of the reaction solution that storage is carried by the taking-out piping 8 of reaction solution, the gas contained in the reaction solution that the gas phase part of this storage tank produces is transferred to sodium hydroxide remove the harm device 13 by being connected in the exhaust pipe 14 of this storage tank, this gas is submerged in the solution that comprises sodium hydroxide.In addition, the gas phase part of this sodium hydroxide remove the harm device 13 also can be equipped with the exhaust pipe 15 that discharges the gas after being detoxified.

[0099] [Example]

[0100] Next, the present invention will be described in detail using Examples and Comparative Examples, but the present invention is not limited to the Examples.

[0101] pH measurement method

[0102] The pH of 30 mL of the tetraalkylammonium hydroxide solution and the tetraalkylammonium hypochlorite solution was measured using a benchtop pH meter (LAQUA F-73, manufactured by Horiba, Ltd.) The pH measurement was performed after the solution stabilized at 25°C.

[0103] <Calculation method for available chlorine concentration and hypochlorite ion concentration>

[0104] To a 100 mL Erlenmeyer flask were added 0.5 mL of a treatment solution (tetraalkylammonium hypochlorite solution), 2 g of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special grade reagent), 8 mL of 10% by mass acetic acid, and 10 mL of ultrapure water, and the mixture was stirred until the solid matter dissolved to obtain a brown solution.

[0105] The prepared brown solution was subjected to redox titration using a 0.02 M sodium thiosulfate solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., for volumetric analysis) until the color of the solution changed from brown to very light yellow. Subsequently, the starch solution was added to obtain a pale purple solution.

[0106] 0.02M sodium thiosulfate solution was further added to the solution until the solution became colorless and transparent, and the available chlorine concentration was calculated. Furthermore, the hypochlorite ion concentration was calculated based on the obtained available chlorine concentration. For example, if the available chlorine concentration was 1% by mass, the hypochlorite ion concentration would be 0.73% by mass.

[0107] Chlorine yield

[0108] The chlorine yield is calculated as the ratio (%) of the number of moles of hypochlorite ions generated relative to the number of moles of chlorine molecules supplied to the organic alkaline solution. If the total amount of chlorine added to the organic alkaline solution reacts (without decomposition), the chlorine yield is 100%. If the hypochlorite ions decompose during the reaction, the chlorine yield decreases.

[0109] <Evaluation method for storage stability>

[0110] The tetraalkylammonium hypochlorite solution was transferred to a glove bag. After the carbon dioxide concentration inside the glove bag reached 1 ppm or less, the solution was transferred to a PFA (perfluoroalkoxy fluororesin: tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) container and sealed. After 10 days of storage at 23°C in a light-shielded environment, the hypochlorite ion concentration of the tetraalkylammonium hypochlorite solution in the PFA container was measured. A hypochlorite ion concentration ratio (concentration after 10 days / initial concentration) of 80% or more and 100% or less was considered good, 60% or more and less than 80% was considered acceptable, and less than 60% was considered poor.

[0111] <Example 1>

[0112] A PFA fluororesin reaction tube (8 mm inner diameter, 1 m length) was placed horizontally, forming a spiral reaction tube with a diameter of 50 mm and six rotations around the horizontal axis. A tetramethylammonium hydroxide solution (12.0 mass% concentration, pH 14.1, liquid temperature 5°C) was supplied from the inlet of the reaction tube at 370 ml / min, and chlorine was supplied at 209.8 mmol / min. Only the reaction liquid obtained from the outlet of the reaction tube within one minute of the start of operation was discarded for tube replacement, and then sampling was continued for five minutes. The liquid retention time was 8 seconds, and the reaction tube alternated between gas and liquid phases in the direction of transfer. The unreacted chlorine content, calculated from the effective chlorine concentration in a sodium hydroxide solution (10 mass% concentration, 1000 ml) prepared in a subsequent step to prevent chlorine leakage, was no more than 100 mass ppm of the total chlorine supplied. As a result, a tetramethylammonium hypochlorite solution (effective chlorine concentration: 3.9% by mass, pH: 13.4, liquid temperature: 17° C.) was obtained. The chlorine yield was 99% or higher, and the storage stability was excellent.

[0113] After the above sampling, continuous operation was continued for 2 hours under the same conditions. The liquid composition of the sample taken 5 minutes after 1 hour from the start of operation was 3.9% by mass of available chlorine and 13.4% by pH. The liquid composition of the sample taken 5 minutes after 2 hours from the start of operation was 3.9% by mass of available chlorine and 13.4% by pH. The hourly production rate was 23 L / H.

[0114] Comparative Example 1

[0115] As a comparative example, an experimental example in which the processing of the reaction tube in Example 1 was not performed is shown.

[0116] A reaction tube (8 mm in inner diameter, 1 m in length) made of PFA, a fluororesin, was extended into a straight tube and placed in the horizontal direction. From one end of the reaction tube, a tetramethylammonium hydroxide solution (concentration 12.0 mass %, pH 14.1, liquid temperature 5°C) was supplied at 370 ml / min, and chlorine was supplied at 209.8 mmol / min. This caused short-circuiting of chlorine gas in the reaction tube, making the liquid supply unstable and reducing the liquid supply to 140 ml / min. The liquid retention time was 22 seconds, and in the reaction tube, the gas phase and the liquid phase were two layers, one above the other, and did not alternate in the transfer direction (see Figure 3 (b)). The reaction liquid obtained from the outlet of the reaction tube was sampled continuously for 2 minutes. The unreacted chlorine, calculated based on the effective chlorine concentration in the sodium hydroxide solution (10% by mass, 1000 ml) prepared in a subsequent step to prevent chlorine leakage, accounted for 50% of the total chlorine supplied. As a result, a tetramethylammonium hypochlorite solution (effective chlorine concentration 4.5% by mass, pH 11.0, liquid temperature 18°C) was obtained. The chlorine yield was 90% and the storage stability was poor.

[0117] <Example 2>

[0118] A PFA fluororesin reaction tube (8 mm inner diameter, 1 m length) was placed horizontally, forming a spiral reaction tube by rotating three and a half turns of 100 mm around the horizontal axis. A tetramethylammonium hydroxide solution (4.8% by mass, pH 13.7, 5°C) was supplied from the inlet of the reaction tube at 200 ml / min, and chlorine was supplied at 12.5 mmol / min. Only the reaction liquid obtained from the outlet of the reaction tube within one minute of the start of operation was discarded for tube replacement, and then sampling was continued for five minutes. The liquid retention time was 15 seconds, and the gas phase and liquid phase alternated in the direction of transfer within the reaction tube. The unreacted chlorine, calculated based on the effective chlorine concentration in a sodium hydroxide solution (10% by mass, 1000 ml) prepared in a subsequent step to prevent chlorine leakage, was equivalent to 500 ppm by mass of the total chlorine supplied. As a result, a tetramethylammonium hypochlorite solution (effective chlorine concentration: 0.4% by mass, pH: 13.6, liquid temperature: 6° C.) was obtained. The chlorine yield was 99% or higher, and the storage stability was excellent.

[0119] <Example 3>

[0120] An experimental example in which the processing of the reaction tube in Example 2 was not performed is shown.

[0121] A reaction tube (8 mm in inner diameter, 1 m in length) made of PFA, a fluororesin, was extended into a straight tube and placed in the horizontal direction. From one end of the reaction tube, a tetramethylammonium hydroxide solution (4.8% by mass, pH 13.7, liquid temperature 7°C) was supplied at 200 ml / min, and chlorine was supplied at 12.5 mmol / min. Only the reaction liquid obtained from the outlet side of the reaction tube within 1 minute of the start of operation was discarded for replacement in the tube, and then sampling was continued for 5 minutes. The liquid retention time was 15 seconds, and in the reaction tube, the gas phase and the liquid phase alternated in the transfer direction (refer to Figure 3 (a)). The unreacted chlorine, calculated based on the effective chlorine concentration in the sodium hydroxide solution (10% by mass, 1000 ml) prepared in a subsequent step to prevent chlorine leakage in the reaction tube, accounted for 5% of the total chlorine supplied. The result was a tetramethylammonium hypochlorite solution (effective chlorine concentration 0.4% by mass, pH 13.6, liquid temperature 8°C). The chlorine yield was over 99%, and the storage stability was excellent.

[0122] <Example 4>

[0123] A spiral reaction tube identical to the one used in Example 1 was set up horizontally. A tetramethylammonium hydroxide solution (25.0% by mass, pH 14.4, liquid temperature 6°C) was supplied from the inlet of the reaction tube at 75 ml / min, and chlorine was supplied at 75.9 mmol / min. Only the reaction liquid obtained from the outlet of the reaction tube within one minute of the start of operation was discarded for replacement within the tube, and then sampling was continued for 5 minutes. The liquid retention time was 40 seconds, and within the reaction tube, the gas phase and liquid phase alternated in the direction of transfer. The unreacted chlorine, calculated based on the effective chlorine concentration in a sodium hydroxide solution (10% by mass, 1000 ml) prepared in a subsequent step in the reaction tube to prevent chlorine leakage, was equivalent to 0.2% of the total amount of chlorine supplied. The result was a tetramethylammonium hypochlorite solution (6.7% by mass, pH 13.8, liquid temperature 30°C). The chlorine yield was over 99% and the storage stability was excellent.

[0124] <Example 5>

[0125] An experimental example in which the processing of the reaction tube in Example 4 was not performed is shown.

[0126] A straight tubular reaction tube identical to the one used in Comparative Example 1 was set horizontally. A tetramethylammonium hydroxide solution (25.0% by mass, pH 14.4, liquid temperature 6°C) was supplied from one end of the reaction tube at 75 ml / min, and chlorine was supplied at 75.9 mmol / min. Only the reaction liquid obtained from the outlet of the reaction tube within 1 minute of the start of operation was discarded for in-tube replacement, and then sampling was continued for 5 minutes. The liquid retention time was 40 seconds, and within the reaction tube, the gas phase and liquid phase alternated in the direction of transfer. The unreacted chlorine, calculated based on the effective chlorine concentration in the sodium hydroxide solution (10% by mass, 1000 ml) prepared in a subsequent step of the reaction tube to prevent chlorine leakage, accounted for 13% of the total amount of chlorine supplied. As a result, a tetramethylammonium hypochlorite solution (6.0% by mass, pH 14.0, liquid temperature 27°C) was obtained. The chlorine yield was over 99% and the storage stability was acceptable.

[0127] <Example 6>

[0128] A PTFE reaction tube (11 mm inner diameter, 10 m length) was formed into a spiral reaction tube, rotating 20 times around a horizontal axis at a diameter of 150 mm. This reaction tube was placed horizontally in a container filled with cold water, also cooling the reaction tube. A tetramethylammonium hydroxide solution (25% by mass, pH 14.4, 5°C) was supplied from the inlet of the reaction tube at 50 ml / min, and chlorine was supplied at 68.3 mmol / min. The reaction liquid obtained from the outlet of the reaction tube within 20 minutes of the start of operation was discarded and used for tube replacement, followed by continuous sampling for 5 minutes. The liquid retention time was 19 minutes, with the gas phase and liquid phase alternating in the direction of transfer within the reaction tube. Unreacted chlorine, calculated from the effective chlorine concentration in a sodium hydroxide solution (10% by mass, 1000 ml) prepared in a subsequent step to prevent chlorine leakage, corresponded to less than 10 ppm of the total chlorine supplied. As a result, a tetramethylammonium hypochlorite solution (effective chlorine concentration 8.8% by mass, pH 12.0, liquid temperature 15° C.) was obtained. The chlorine yield was 99% or higher, and the storage stability was excellent.

[0129] <Example 7>

[0130] A spiral reaction tube similar to that used in Example 6 was placed horizontally. A tetramethylammonium hydroxide solution (concentration 10.0 mass %, pH 14.0, liquid temperature 15°C) was supplied from the inlet of the reaction tube at 2.5 L / min, and chlorine was supplied at 1.12 mol / min. The reaction liquid obtained from the outlet of the reaction tube was continuously sampled after the start of chlorine supply. The liquid retention time was 20 seconds. Figure 2As shown, a stable tetramethylammonium hypochlorite solution (effective chlorine concentration 3.1% by mass, pH 13.3, liquid temperature 25°C) was obtained one minute after the start of chlorine supply. Within the reaction tube, gaseous and liquid phases alternated in the direction of transfer. The unreacted chlorine, calculated based on the effective chlorine concentration in a sodium hydroxide solution (10% by mass, 1000 ml) prepared in a subsequent step in the reaction tube to prevent chlorine leakage, corresponded to less than 100 ppm by mass of the total amount of chlorine supplied. The chlorine yield was 99% or higher, and storage stability was excellent.

[0131] <Example 8>

[0132] A reaction tube made of PTFE (11 mm inner diameter, 3 m length) as a fluororesin was formed into a spiral reaction tube by rotating 6 times with a diameter of 150 mm around the horizontal axis. The reaction tube was set in the horizontal direction. A tetramethylammonium hydroxide solution (5.0 mass % concentration, pH 13.7, liquid temperature 12°C) was supplied from the inlet side of the reaction tube at 110 ml / min, and chlorine was supplied at 24.3 mmol / min. After the start of the chlorine supply, the reaction liquid obtained from the outlet side of the reaction tube was continuously sampled. The liquid retention time was 2 minutes, as shown in FIG. Figure 2 As shown, a stable tetramethylammonium hypochlorite solution (effective chlorine concentration 1.5% by mass, pH 13.0, liquid temperature 17°C) was obtained 3 minutes after the start of chlorine supply. Within the reaction tube, the gas phase and liquid phase alternated in the direction of transfer. The amount of waste liquid generated during the replacement operation until the reaction stabilized was 0.2 L, and the unreacted chlorine content was less than 100 ppm by mass of the total amount of chlorine supplied.

[0133] Comparative Example 2

[0134] A cylindrical reaction tube (made of PTFE) with a diameter of 150 mm was charged with 1700 mL of a tetramethylammonium hydroxide solution (5.0% by mass, pH 13.7, and a liquid temperature of 12° C.). The tetramethylammonium hydroxide solution of the same composition was supplied to the reactor at a rate of 110 mL / min, and chlorine gas was supplied to the reactor at a rate of 24.3 mmol / min. The generated tetramethylammonium hypochlorite solution was extracted from a liquid extraction port located at a height of 100 mm from the bottom of the reactor. The liquid retention time was 16 minutes. Figure 2 As shown, a stable tetramethylammonium hypochlorite solution (effective chlorine concentration 1.5% by mass, pH 13.0, liquid temperature 17°C) was obtained 60 minutes after the start of chlorine supply. Within the reaction tube, the gas phase and liquid phase were separated into two layers, one above the other, and did not alternate in the direction of transfer. The amount of waste liquid generated during the replacement operation until the reaction stabilized was 6.7 L, and the unreacted chlorine accounted for 2% of the total amount of chlorine supplied.

[0135] <Example 9>

[0136] A spiral reaction tube, identical to the one used in Example 8, was installed horizontally. A tetramethylammonium hydroxide solution (8.5% by mass, pH 14.0, liquid temperature 10°C) was supplied from the inlet of the reaction tube at 1000 ml / min, and chlorine was supplied at 436 mmol / min. Within the reaction tube, gas and liquid phases alternated in the direction of flow. The tetramethylammonium hypochlorite solution (3.0% by mass available chlorine concentration, pH 13.0, liquid temperature 20°C) obtained from the outlet of the reaction tube had an hourly production rate of 62 L / h.

[0137] Comparative Example 3

[0138] A tetramethylammonium hypochlorite solution (effective chlorine concentration 3.0 mass %, pH 13.0, liquid temperature 5° C.) was obtained using the production method of Example 3 in the prior art (International Publication No. 2019 / 225541). The reaction time of this production method was 180 minutes, and the hourly production rate was 0.34 L / H.

[0139] [Table 1]

[0140]

[0141] *The “liquid-to-gas ratio” in the table is the ratio of the volume flow rate of the halogen (chlorine gas) to the volume flow rate of the organic alkaline solution (tetramethylammonium hydroxide solution).

[0142] Description of Reference Numerals

[0143] 1: Reaction tube; 2: Tetraalkylammonium hydroxide solution supply piping; 3: Chlorine gas supply piping; 4: Nitrogen gas supply piping; 5: Piping valve; 6: Piping valve; 7: Piping valve; 8: Reaction liquid removal piping; 9: Reaction liquid temperature measuring device; 10: Reaction tube temperature control jacket; 11: Reaction liquid pH measuring device; 12: Reaction liquid storage tank; 13: Sodium hydroxide decontamination device; 14: Exhaust piping; 15: Exhaust piping; 16: Gas phase section; 17: Liquid phase section.

Claims

1. A method for producing a halogen oxyacid, comprising the following steps: An organic base solution and a halogen are continuously supplied from one end of a reaction tube toward the other end, so that a liquid phase and a gas phase alternately exist in a transfer passage of the reaction tube, and the organic base solution and the halogen are mixed in a gas-liquid state in the liquid phase and / or the gas phase. The reaction tube is formed into a spiral shape with a direction extending from one end to the other end as an axis and the axis as a spiral axis. The diameter of the supply pipe for supplying the gas phase and the liquid phase is set to be the same as or smaller than the diameter of the reaction tube.

2. The method for producing a halogen oxyacid according to claim 1, wherein The ratio of the volume flow rate of the halogen supplied to the reaction tube to the volume flow rate of the organic alkaline solution is 1 to 50.

3. The method for producing a halogen oxyacid according to claim 1, wherein The reaction tube is configured to extend in a substantially horizontal direction.

4. The method for producing a halogen oxyacid according to claim 1 or 2, wherein The reaction tube is a reaction tube containing a fluororesin.

5. The method for producing a halogen oxyacid according to claim 1 or 2, wherein The average inner diameter of the reaction tube is greater than 5 mm.

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