HK1188176B - Method for producing an aqueous stable chlorine dioxide solution - Google Patents

Description

The present invention relates to a process for the preparation of a very pure, aqueous, long-term and storage stable, and thus transportable, chlorine dioxide solution with a concentration of chlorine dioxide of 0.3 to 4.5% by weight, comprising the steps of chlorite preparation, peroxodisulphate preparation and the combination of chlorite and peroxodisulphate in an aqueous system and in a molar ratio of peroxodisulphate to chlorite [S._{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}] of greater than 1 in the formation of the aqueous chlorine dioxide solution, without adding any additional buffer to produce the aqueous chlorine dioxide solution.

aqueous solutions of chlorine dioxide (ClO)_{2 and}However, solutions of chlorine dioxide are generally considered to be difficult to handle because gaseous chlorine dioxide escapes easily from solutions and is explosive at higher concentrations. Therefore, solutions of chlorine dioxide for the above-mentioned applications are usually not sold as finished solutions but are produced and applied freshly when needed, i.e. on site.

Various methods are known for the production of aqueous chlorine dioxide solutions.

For example, an aqueous chlorine dioxide solution can be produced by converting a sodium chlorite solution with a hydrochloric acid solution (the so-called hydrochloric acid chlorite process). This process has the disadvantage, among other things, that chlorine dioxide is not stable in such a solution and decomposes to chlorate and chloride within a short time.

The so-called chlorine-chlorite process involves the addition of a sodium chlorite solution with either chlorine or hypochloric acid. However, this process has the disadvantage that gaseous chlorine and hypochloric acid are difficult to handle. In addition, this process produces a significant amount of chlorate as an undesirable byproduct, which reduces the yield of chlorine dioxide and thus the oxidation power of the solution.

As an alternative to the two methods above, it has been proposed to produce a solution of chlorine dioxide by oxidation of chlorite with peroxodisulphate. For example, WO-A-96/33947 describes a method for the production of an aqueous chlorine dioxide solution by converting a solution of chlorite with a halogen-free oxidizer at a pH of 5.5 to 9.5 at room temperature until the chlorite is essentially completely converted into chlorine dioxide. Other Other 2ClO_{2 and} ^{- I 'm not .}+ S_{2 and}O₈ ^2-→ 2ClO_{2 and} ^{• the}+ 2SO₄ ^2-The Commission Other Other Other

On the basis of this sum equation, it is generally assumed that an equivalent peroxodisulphate oxidizes two chlorite equivalents. Consequently, WO-A-96/33947 proposes to use peroxodisulphate in a quantity between one and two times the stoichiometric quantity required to oxidize the chlorite._{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}] in the range of 0,5 to 1,0.

A similar process is also described in US Patent 2,323,593, wherein the examples of this patent show molar ratios of peroxodisulphate to chlorite [S]_{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}The US patent 2,323,593 further states that the ratio of peroxodisulphate to chlorite [S] is_{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}The effects of the reaction are not as strong as the effects of the reaction.

Err1:Expecting ',' delimiter: line 1 column 460 (char 459)_{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}] of greater than 2 is used, the peroxodisulphate solution and the chlorite solution being buffered.

However, the methods described above have a number of disadvantages which make their application difficult.

Err1:Expecting ',' delimiter: line 1 column 377 (char 376)

In addition, the methods known to the state of the art have the disadvantage that the controlled implementation requires temperatures above room temperature or, alternatively, long reaction times. Furthermore, systematically fluctuating, highly temperature-dependent reaction times and yields and the resulting varying degrees of purity are further problems for the methods used so far.

The present invention is therefore intended to provide a solution of chlorine dioxide which has a high storage stability and which therefore does not necessarily have to be produced locally but can also be marketed as a finished solution.

This task is solved by the embodiments indicated in the claims.

In particular, a method for the preparation of an aqueous chlorine dioxide solution with a concentration of chlorine dioxide of 0,3 to 4,5% by weight is provided, which includes the following steps: (a) Provision of chlorite, (b) Provision of peroxodisulphate, (c) Combining of chlorite and peroxodisulphate in an aqueous system and in a molar ratio of peroxodisulphate to chlorite [S]_{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}] of a purity by weight of more than 0,01%, where no additional buffer is added to produce the aqueous chlorine dioxide solution.

Steps (a) and (b) can be performed in any order.

In step (a) of the invention process, chlorite (ClO) is converted into a_{2 and} ^{- I 'm not .}The chlorite can be obtained in the form of the chloric acid HClO, as described in the invention._{2 and}Preferably, chlorites from the group consisting of alkali metal chlorites, especially lithium chlorite, sodium chlorite and potassium chlorite, mineral metal chlorites, especially magnesium chlorite and calcium chlorite, ammonium chlorites, especially ammonium chlorite (NH₄CIO_{2 and}The use of the product in the manufacture of other products is not permitted, but the use of the product in the manufacture of other products is permitted.

However, solid sodium chlorite, which is available on the market, can be used, for example, and can contain up to about 25% by weight of sodium chloride, preferably up to about 20% by weight of sodium chloride, preferably up to about 10% by weight of sodium chloride, as sodium chloride does not interfere with the conversion of peroxodisulphate to chlorine dioxide and does not affect the stability of the resulting chlorine dioxide.

In step (b) of the process of the invention, peroxodisulphate (S) is added to the_{2 and}O₈ ^2-The invention describes the process by which peroxodisulphate can be obtained in the form of peroxodiic sulphuric acid H._{2 and}S_{2 and}O₈The peroxodisulphates of the group consisting of alkali metal peroxodisulphates, in particular lithium peroxodisulphates, sodium peroxodisulphates and potassium peroxodisulphates, tertiary metal peroxodisulphates, in particular magnesium peroxodisulphates and calcium peroxodisulphates, ammonium peroxodisulphates, in particular ammonium peroxodisulphates (NH₄(b)_{2 and}S_{2 and}O₈The selection of the products is based on the following criteria: (i) the use of a mixture of methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, methanol, and other methanol, and the other metals are to be used for the manufacture of the products, and the products are used for the manufacture of the products.

Peroxodisulphate can be used either as a solid or in solution, especially in aqueous solution. It is preferable to use peroxodisulphate in the purest form possible, as impurities may interfere with the conversion of chlorite with peroxodisulphate to chlorine dioxide and may reduce the stability of the resulting chlorine dioxide. In a preferred embodiment of the process of the invention, peroxodisulphate is provided in solid form as a formling, tablet, capsule or pellet.

In addition, it is also possible to provide chlorite and peroxodisulphate together, for example as a 2-phase binary solid mixture or as a formulation, tablet, capsule or pellet containing both components separately and dissolving with a time delay.

The aqueous solutions may also contain other suitable co-solvents, such as halogenated or non-halogenated organic solvents. In a preferred embodiment, the further solvent is a suitable solution for the reaction, preferably from the group consisting of methanol, methanol, n-propanol, iso-propanol, B-propanol, and mixed methanol. A further solvent may be used, preferably in a volume of 10% to 80% by volume.

Step (c) of the method of the invention involves the combination of chlorite and peroxodisulphate in an aqueous system to form the aqueous chlorine dioxide solution. This combination can be done by any suitable method known to the state of the art. Preferably, the combination of the two components is done by mixing. Mixing can also be done by any suitable method known to the professional. For example, mixing can be done on a laboratory scale with a laboratory tube. On a large-scale, for example, mixing can be done in a mixing vessel. Preferably, mixing is done in such a way that a solution of the two components, which contains no more essential substances, is homogeneous. The advantage of using a chlorine peroxide fixative is that the conversion is accelerated by the use of a chlorine dioxide fixative.

In a preferred embodiment of the process of the invention, chlorite and peroxodisulphate are provided in solid form or in aqueous solution in steps (a) and (b), whereas in step (c) (c1) both components are dissolved in water before being combined, if both components are provided in solid form, or (c2) both components are provided in solid form simultaneously or successively in an aqueous solvent, or (c3) both solutions are combined if both components are provided in aqueous solutions, or (c4) both components are provided in aqueous solution and simultaneously or successively in an aqueous solvent. The water is then added to the solution to make the aqueous chlorine dioxide solution.

Preferably, the combination in step (c1) is by dissolving the two components together, simultaneously or successively, in water, when both components are provided in solid form. For example, if chlorite and peroxodisulphate are provided as a binary solid mixture or formling, this solid mixture or formling can simply be dissolved in water and then the two solutions thus obtained can be essentially dissolved simultaneously or successively in the molar ratio of the invention.

In step (c2), the two components are preferably introduced into an aqueous solvent in solid form one after the other, in particular, it is preferable to first present peroxodisulphate in aqueous solution and then to add chlorite, whether in solid form or aqueous solution.

In step (c3) both solutions are preferably combined at the same time in the molar ratio of the invention, but it is also possible to first present the aqueous solution with peroxodisulphate and then add the chlorite solution.

In step (c4), the two components are preferably prepared in aqueous solution and added successively to an aqueous solvent, in which case the order of addition is irrelevant and either the aqueous peroxodisulphate solution or the chlorite solution may be added first and the other solution added afterwards.

The preferred method is the method described in (c3), whereby both components are first dissolved separately in an aqueous solvent and then the two solutions are combined and mixed.

In particular, it is preferable to present an aqueous solvent, preferably demineralised or distilled water, in the desired quantity and then to separate the desired quantities from it to produce the aqueous solutions of the two components, to prepare the solutions and to add them back to the aqueous solvent.

In all cases (c1) to (c4), the aqueous solutions may contain chlorite at any appropriate concentration up to the saturation concentration of the corresponding chlorite salt. The specific saturation concentration is not a fixed value but depends, for example, on the temperature used and the nature of the particular chlorite salt. Sodium chlorite, for example, has a saturation concentration of about 64.5% by weight at 20°C. However, it is preferable to set the concentration of aqueous solutions of chlorite to not more than about 5% by weight, in particular not more than 2% by weight and not more than 1% by weight. The concentration of sulphur peroxide in the particular solution may vary from 20% to 5%, for example, the concentration of sulphur peroxide may not be more than 5% by weight at the temperature of the particular solution used, but may be more than 20% by weight.

The water used to produce the chlorine dioxide solution of the invention may be any suitable water, such as tap water, but preferably, demineralized or distilled water is used, as this reduces the foreign matter content of the solution, which is beneficial in terms of better conversion of chlorite and peroxodisulphate to chlorine dioxide and increased stability of the resulting chlorine dioxide.

The combination of chlorite and peroxodisulphate results in the formation of chlorine dioxide, which is present in the form of an aqueous solution as it is carried out in an aqueous system.

After the production of chlorine dioxide in more aqueous solution, it is also possible to add solvents which are not miscible with water, such as organic solvents, especially dichloromethane, chloroform and/or tetrachloromethane, and to transfer chlorine dioxide to the organic phase, thus producing stable solutions of chlorine dioxide in organic solvents.

It was surprisingly found that, in this implementation, contrary to the sum equation (1) described above, an equivalent peroxodisulphate reacts with an equivalent chlorite to form a stable solution of chlorine dioxide, while maintaining the molar ratios of peroxodisulphate to chlorite of greater than 1 according to the invention. Other Other CIO_{2 and} ^{- I 'm not .}+ HS_{2 and}O₈ ^{- I 'm not .}→ [ClO_{2 and} ^{• the} HSO₄ ^{• the}] + SO₄ ^2-(2) Other Other Other

The HS is_{2 and}O₈ ^{- I 'm not .}Autocatalytically produced from S_{2 and}O₈ ^2-The reaction of a chlorite equivalent with a peroxodisulfate equivalent results in the addition of a chlorine dioxide radical ClO to the chlorine dioxide radical._{2 and} ^{• the}whether or not a hydrogen sulphate radical HSO₄ ^{• the}These two radicals stabilize each other associatively, represented by the radical pair [ClO]_{2 and} ^{• the} HSO₄ ^{• the}It is also conceivable that such a radical pair would have an association with water of the form [ClO]_{2 and} ^{• the} H_{2 and}O HSO₄ ^{• the}The hydrogen sulphate radical itself has been considered unstable until now.

It is further assumed, without being bound by any theory, that the stabilisation of the radical complex [ClO]_{2 and} ^{• the} HSO₄ ^{• the}] can be supported by the following observations: 1) The chlorine dioxide solution has an acid pH due to the proton of the hydrogen sulphate radical (preferably in the pH range of 2.5 to 3). This places each chlorine dioxide radical in a weakly acidic environment and is thought to contribute to the stabilization of the chlorine dioxide radical.2) The association with the hydrogen sulphate radical could lead to an increase in hydration, which would increase water solubility. Furthermore, the vapour pressure of the radical could be reduced by the association.3) The association may also reduce the tendency of the chlorine dioxide radical to regrow into chlorite.4) It is thought that due to the chemical composition of the chlorine dioxide radical, there is no possibility of the chemical radical becoming reactive with water or solvent (such as sulfur sulphate or sulfur sulfur sulphate), or by the formation of a membrane-like chemical compound (such as chlorine oxide), or by the formation of a chemical compound called chlorine sulphate._{2 and} ^{• the} HSO₄ ^{• the}In oxidation reactions, the radical complex reacts to form the non-environmentally relevant chloride and sulphate anions. In contrast, conventional, i.e. unstabilized chlorine dioxide solutions tend to explode when decomposed due to the formation of chlorine and oxygen.6) The concentration of the chlorine dioxide radical is the determining quantity for the formation of radical pairs.

The formation of the radical pair association described above is supported by experimental studies showing that this radical pair association is distilled as a whole and can thus enter the gas phase and is also membrane-bound._{2 and} ^{• the} HSO₄ ^{• the}The oxidation potential of the hydrogen sulphate radical is fully available as an oxidation potential with another electron equivalent and there is therefore no loss of oxidation potential. This has been demonstrated by photometry and titration. In total, six electron equivalents are available, five for the reduction of chlorine dioxide to chloride and one for the reduction of the hydrogen sulphate radical.

In view of the above, the method of the invention is characterised by the fact that it assumes a different stoichiometry for the conversion of chlorite and peroxodisulphate to chlorine dioxide compared to the methods known at the time of the invention.

Therefore, in step (c) of the inventive process, chlorite and peroxodisulphate are obtained in a molar ratio of peroxodisulphate to chlorite [S_{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}Thus, a chlorite equivalent with a molar excess of peroxodisulphate is converted, whereas conventional methods usually use only about 0.5 peroxodisulphate equivalents for a chlorite equivalent.

In a preferred embodiment of the present invention, the starting materials are obtained in a molar ratio of peroxodisulphate to chlorite between 1 and 2 (1 < S)_{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}The solution is generally less stable (though slightly so by peroxodisulphate) than the solution, so the molar ratio of 1 to 2 described above gives a chlorine dioxide solution with increased stability.

In another preferred embodiment of the present invention, the starting materials are used in a molar ratio of peroxodisulphate to chlorite greater than 2, especially preferred by greater than 4, even more preferred by greater than 10. It is also possible to use a ratio of peroxodisulphate to chlorite up to about 100. In this embodiment, peroxodisulphate is used in a greater excess in relation to chlorite to achieve a faster or complete conversion of the chlorite used to chlorine dioxide.

The reaction is accelerated and almost quantitative by maintaining the molar ratio of the invention. In particular, it is preferable to achieve an yield of more than about 80%, in particular more than about 90%, in particular more than 95% in relation to the amount of chlorite used.

It was further established that for effective conversion of chlorite and peroxodisulphate to chlorine dioxide it is not necessary to adjust the reaction solution to a specific pH by adding a buffer. Rather, it was found that adding the buffer would introduce further foreign substances into the aqueous solution, which would reduce the rate of reaction to chlorine dioxide and the stability of the chlorine dioxide in the solution. Accordingly, no buffer is added to the aqueous chlorine dioxide solution according to the invention. Thus, no additional buffer is added during the manufacture. This does not mean that the resulting solution contains no buffer. For example, a hydrogen sulphate/sulphate bubble may form during the reaction during the conversion of sulphate.

A commonly used buffer for stabilizing chlorine dioxide is a mixture of at least one weak acid and its conjugate base._a)The pH of a solution in water is maintained within a pH range by adding a buffer, so that any buffer system has a pH range within which the pH value does not change significantly when a strong acid is added.

In particular, no buffer selected from the group consisting of an acetate buffer, a phosphate buffer, a borate buffer, a citrate buffer and a carbonate buffer is used according to the invention.

In particular, a buffer is not preferably added to the aqueous chlorite solution provided in step (a) to buffer the solution in a pH range of 9 to 12 and a buffer is not preferably added to the aqueous peroxodisulphate solution provided in step (b) to buffer the solution in a pH range of 3 to 9.

In one embodiment of the present invention, the chlorine dioxide solution is prepared by combining a solution of chlorite with a solution of peroxodisulphate. Preferably, the peroxodisulphate solution is used in such a concentration that it has a pH value in the range of about 4 to about 8. In one embodiment, the pH value of the peroxodisulphate solution is about 4 to about 6. In another embodiment, the pH value is about 6 to about 8.

If the aqueous solutions of chlorite and peroxodisulphate described above are combined, the pH of the solution during the reaction of chlorite with peroxodisulphate to chlorine dioxide is preferably about 2 to about 4, i.e. the pH of the aqueous solution is stabilized as the reaction of chlorite with peroxodisulphate to chlorine dioxide is completed to about 2 to about 4.

The resulting solutions of chlorine dioxide may be added after preparation with a buffer, preferably a buffer buffering in a pH range of about 2 to 4.

The method of the present invention can be performed at any suitable temperature, but it is advantageous to perform the conversion of chlorite and peroxodisulphate at relatively low temperatures in the range of about 0°C to about 25°C. In contrast, in conventional processes, higher temperatures generally above 25°C are required to achieve an accelerated conversion of chlorite with peroxodisulphate to chlorine dioxide. In a preferred embodiment of the present invention, the combination of peroxodisulphate and chlorite is performed at a temperature in the range of about 0°C to about 25°C, preferably in the range of about 2°C to about 20°C. The step (c) of conversion is generally reduced to about 5°C. It is preferable to perform this conversion at a temperature in the range of about 15°C, since the formation of the by-products of the reaction is somewhat more stable than at about 25°C.

It is still advantageous to maintain this temperature range not only during the combination of the chlorite component with the peroxodisulphate component but until the conversion of chlorite with peroxodisulphate to chlorine dioxide is essentially complete. This is preferably done by bringing the aqueous solutions used to the appropriate temperature before the combination and then keeping them in this temperature range until the conversion to chlorine dioxide is essentially complete. In addition to the temperature of the solutions used, it is also advantageous to maintain the environment during the combination and until the completion of the reaction to the above described steps. This can be done, for example, in a refrigerator or under a refrigerator.

In another preferred embodiment, the chlorine dioxide solution obtained by the method of the invention is maintained or stored in this temperature range after completion of implementation. Pure chlorine dioxide has a boiling point of 11°C at 1013 mbar. Therefore, the aqueous chlorine dioxide solution obtained by the method of the invention is preferably stored below about 11°C, especially at a temperature in the range of about 0°C to about 11°C.

If the combination of chlorite and peroxodisulphate is carried out in the preferred temperature range from about 0°C to about 25°C, preferably greater than 0°C to about 11°C, the occurrence of side reactions and thus of undesirable by-products such as chlorine, hypochlorite and chlorate can be essentially avoided during the formation of chlorine dioxide.

Preferably, the method of the invention is performed in the absence of light. It was found that the formation of by-products is possible in the presence of UV radiation or sunlight. The formation of by-products is detrimental, as by-products or foreign substances were found to destabilize the chlorine dioxide solution of the invention. The fewer by-products are in the reaction mixture, the more stable the solution is in the long term.

The method of the invention allows a near-quantitative turnover (i.e. a turnover of more than 95%) of chlorite to chlorine dioxide to be obtained in about 72 hours. Preferably a near-quantitative turnover is obtained after 48 hours, especially after 24 hours, preferably for 0.3-0.6% by weight solutions, and preferably after 48 hours, preferably after 24 hours. For higher-weight solutions (e.g. concentrations of 1% or less by weight) the concentration of chlorine peroxide can also be increased rapidly, especially after a constant or constant temperature of 15 minutes or less.

In contrast, the state of the art (see, for example, WO-A-96/33947) has described reaction times to quantitative implementation of about 12 days for the production of higher concentrated solutions of chlorine dioxide.

Preferably, the process of the invention at step (c) includes the further step of reacting chlorite with peroxodisulphate until the chlorite has been substantially converted (i.e. more than 95% of the chlorite used) to chlorine dioxide; in a particularly preferred embodiment, the process of the invention at step (c) includes the further step of reacting chlorite with peroxodisulphate for a duration of at least 12 hours, preferably for a duration of at least 24 hours, even more preferably for a duration of at least 36 hours; in another particularly preferred embodiment, the process of the invention at step (c) includes the further step of reacting chlorite with peroxodisulphate for a duration of 12 to 48 hours and preferably for a duration of 24 to 36 hours.

The method of the present invention allows the preparation of solutions of chlorine dioxide with a concentration of 0.3 to 4.5% by weight of chlorine dioxide. Preferably, the method of the present invention produces aqueous solutions of chlorine dioxide up to about 2% by weight, preferably about 1% by weight. Although higher concentrated solutions of chlorine dioxide are more difficult to obtain due to the limited solubility of chlorine dioxide in water, they can nevertheless be realized. When higher concentrations of chlorite are used to produce the solutions of chlorine dioxide in the gas of the present invention, in particular when chlorine concentrations are used in the saturation range of the corresponding chlorine gas, chlorine dioxide solutions with a concentration of up to 4.5% by weight of chlorine dioxide in water can be produced at a concentration of approximately 5 °C. The value of chlorine dioxide can be increased in water and the pressure can be increased at a temperature of approximately 5 °C.

Such mixtures typically contain more than about 4.5 to about 12% by weight of chlorine dioxide, relative to the total amount of chlorine dioxide and water. The solubility of chlorine dioxide in water is decisively affected by foreign substances dissolved in water, which reduce the solubility of chlorine dioxide. This means that the lower the number of foreign substances in the solution, the higher the solubility of chlorine dioxide in water. Since the method of the invention produces solutions of chlorine dioxide with a lower foreign element particle, the solubility of chlorine dioxide in the solutions of the invention is also higher than in conventional chlorine dioxide solutions.

In addition, solutions of chlorine dioxide are well-manageable even at relatively high concentrations of up to about 12% by weight and preferably up to about 2% by weight of chlorine dioxide and do not show a propensity to explode by spontaneous decomposition. However, for safety reasons, the method of the invention prefers solutions of chlorine dioxide with a concentration of up to about 2.5% by weight, particularly up to about 1% by weight and in particular about 0.6% by weight of chlorine dioxide. In contrast, the standard describes solutions of chlorine dioxide as being more stable the more diluted they are. Therefore, in the present state of the art, concentrations of not more than about 0.3% by weight are usually described. However, it is preferable to use solutions of chlorine dioxide with a concentration of up to 0.3% by weight, especially up to about 1% by weight and in particular up to about 0.6% by weight.

The present invention is intended to produce solutions with a concentration of chlorine dioxide in the range of 0.3% to 4.5% by weight, preferably in the range of 0.3% to about 2.5% by weight, and preferably in the range of about 0.3% to about 1% by weight, and particularly preferably in the range of more than 0.3% to about 0.6% by weight, and in particular from about 0.5% to about 0.6% by weight.

The method of the invention allows the production of chlorine dioxide either continuously in the flow operation or in batches in the batch operation.

In another preferred embodiment of the present invention, the solution obtained after the combination in step (c) is filled into a container in which the solution can be stored and/or transported. If the solution is filled into the container, the conversion to chlorine dioxide must not yet be complete. It is also possible that the completion of the reaction of chlorite and peroxodisulphate to chlorine dioxide will take place only after the solution has been refilled in the containers intended for storage or transport of the solution. Therefore, the step of filling can be done before or after the optional step described above of reacting with chlorite peroxides. In other embodiments, the combination is done in a pre-prepared form (clorine) or in a pre-prepared form (dioxide). This is particularly advantageous since the solution is not yet ready for transport, since the most suitable solution is not yet ready for the additional step described.

The method of the invention for the preparation of a chlorine dioxide solution and the chlorine dioxide solutions obtained from it have numerous advantages compared with the state of the art. The method of the invention allows the preparation of a chlorine dioxide solution under extremely mild reaction conditions (especially at a low temperature) using only two components. Furthermore, only a small apparatus is required, for example, since no heating of the reaction mixture is necessary. Furthermore, the method of the invention allows a near-quantitative transformation of chlorine in comparatively short reaction times without the need to add an activator or catalyst component (usually heavy metal) or a defined buffer system.

Due to the simple and complete implementation, the resulting solution contains few other components or foreign substances (such as untransformed starting materials, undesirable by-products, buffers, activators or catalysts), but almost exclusively chlorine dioxide. Surprisingly, it has now been found that this absence of foreign substances in the chlorine dioxide solution significantly improves the stability of the chlorine dioxide solution. Thus, it has been found that the higher the stability of the chlorine dioxide solution and the lower the decomposition tendency of the chlorine dioxide solution, the higher the purity of the chlorine dioxide solution. This results in an increased stability of a chlorine dioxide solution, which is achieved by using a chlorine dioxide solution which is made possible by the use of chemicals which are found to destabilize the solution.

The solution of chlorine dioxide according to the invention is highly selective in its implementation, so that there are only small amounts, if any, of hypochlorite, chlorine and chlorate as foreign substances. The risk of decomposition of chlorine dioxide by possible redox reactions with these components is therefore significantly reduced. The solution of chlorine dioxide according to the invention is therefore durable, in particular for at least one year, without significant decomposition of chlorine dioxide being observed. Therefore, the addition of a stabilizer to the solution of chlorine dioxide according to the invention is also not necessary.

In a preferred embodiment, the process is further limited to the use of the chlorite component and the peroxodisulfate component, with no further components selected from the group consisting of activators, catalysts and stabilizers being used to produce the chloride solution, i.e. no buffer is added to the starting materials or to the resulting chloride dioxide solution. Activators may be, for example, radical initiators. In a particularly preferred embodiment, no further components selected from the group consisting of activators, catalysts and stabilizers may be used to produce the chloride dioxide solution, i.e. no buffer is added to the starting materials or to the resulting chloride dioxide solution. The activators may be, for example, radical initiators. In a particularly preferred embodiment, no further components selected from the group consisting of activators, catalysts and stabilizers may be used to produce the chloride dioxide solution. The catalytic converter may be used, for example, as a transition component, or as an additive, in the production of a particular product, such as a sulphur dioxide, sodium peroxide, alkali, sulphur dioxide, or other alkali, and may also be used as an additive in the production of a particular product, such as a sulphur dioxide, chloride, sulphide, sulphur dioxide, and alkali.

The state of the art, however, describes that only high concentrations of chlorine dioxide accelerate decomposition and that buffer additives or stabilisers are required to increase stability. Other The invention of the method of the present invention does not require the preparation of the solution of chlorine dioxide on site immediately before the intended use, but it is possible to produce and pack a solution of chlorine dioxide in larger quantities and then transport it to the intended use. Other Furthermore, the invention can be applied without problems and without danger at any scale,The Commission has already made a number of recommendations to the Council and the Council on the use of the new technology. Other The solution is immediately ready for use after completion of the manufacturing process of the invention, no further processing, e.g. by absorption columns, desalination, mixing with other solutions, etc., is required. Other The present invention also relates to an aqueous chlorine dioxide solution containing chlorine dioxide in a quantity greater than 0,3% by weight to 4,5% by weight, with a pH of the aqueous solution in the range of 2 to 3 and the solution not containing a buffer.It is much more concentrated than conventional solutions of chlorine dioxide, yet is stable in storage and easy to handle. Other The aqueous chlorine dioxide solution obtained by the method of the invention may contain chlorine dioxide together with the hydrogen sulphate radical in the form of a radical pair association, but the solution does not contain a buffer. In a preferred embodiment, this chlorine dioxide solution does not contain any other components selected from the group consisting of activators, catalysts and stabilizers. Other These solutions of chlorine dioxide have the advantages described above of increased stability even at high concentrations and the associated extended storage and transport capacity.

The solutions of the invention are therefore low in corrosion due to their low acid pH and also have an additional oxidation potential to protect the solution due to the additional hydrogen sulphate radical contained in the solutions (see above sum equation (2)) or a resultant byproduct compared to conventional solutions of chlorine dioxide.

The solutions of chlorine dioxide according to the invention are durable but at least one year storable, i.e. no significant decomposition of chlorine dioxide is observed during this period. Preferably, the solutions of chlorine dioxide according to the invention are storable indefinitely. To increase the storage stability of the solutions of chlorine dioxide according to the invention, they are preferably stored refrigerated, preferably at a temperature in the range from 0 °C to about 25 °C, preferably in the range from about 2 °C to about 20 °C, preferably in the range from about 5 °C to about 15 °C.

Furthermore, it is advantageous that the solutions of chlorine dioxide of the invention are stored in the absence of light, but, surprisingly, since chlorine dioxide in aqueous solution has been found to be significantly more stable against UV radiation or sunlight than in the gas phase, it is sufficient, according to a preferred embodiment, to protect the gas phase above the solution from light within the container in which the solutions are stored, for example by using a translucent film or a transparent barrier or a transparent band.

The aqueous solutions of chlorine dioxide are real solutions of chlorine dioxide in water, whereas chlorine dioxide does not hydrolyze. The vapor pressure of the solutions is determined by Henry's law, i.e. the sum of the partial pressures gives the total pressure. The vapor pressure of chlorine dioxide is temperature dependent and increases with increasing temperature.

However, for a number of reasons it is desirable to keep the vapour pressure of the chlorine dioxide solutions of the present invention as low as possible. For example, a high vapour pressure of chlorine dioxide causes some of the chlorine dioxide to escape from the solution, which reduces the concentration of usable chlorine dioxide. This can lead to significant losses of chlorine dioxide, especially when the storage tank for the chlorine dioxide solution of the present invention is ventilated or open, for example. This allows the chlorine dioxide to gradually pass out of the solution into the gas phase and then escape from the container.

Therefore, it is advantageous to store the aqueous chlorine dioxide solutions of the invention below their boiling point of 11°C, especially in the range of greater than 0°C to 11°C, preferably in the range of 5°C to 11°C.

However, the use of a pressure relief is also advantageous in reducing the vapour pressure of chlorine dioxide. For example, solutions of chlorine dioxide according to the invention can be pressurized at a pressure of about 0.01 to about 10 bar, possibly under inert gases such as nitrogen or similar, preferably in the range of about 0.1 to about 1 bar, thereby further reducing the vapour pressure of chlorine dioxide. However, pressures above the boiling point also lead to a similar result. Thus, solutions of chlorine dioxide according to the invention can also be stored at temperatures up to 40 °C, provided that the quantity of solutions is simultaneously pressurized with an appropriate pressure relief to reduce the concentration of chlorine dioxide in the gas phase.

It has thus been shown that solutions of chlorine dioxide, both according to the invention and conventional, can be stored advantageously in a pressure vessel, preferably at a pressure of 0,01 to about 10 bar, preferably in the range of about 0,1 to about 1 bar.

In a particularly preferred embodiment, the chlorine dioxide solutions of the invention are stored at a temperature in the range of greater than 0°C to about 15°C with a simultaneous pressure increase in the range of about 0,1 bar to about 1 bar.

In another preferred embodiment of the present invention, the chlorine dioxide solutions can also be stored in an inert gas atmosphere.

For example, conventional plastic or metal containers, caps, barrels, glass bottles, etc. are suitable containers. There are no restrictions on the material as long as it is inert to chlorine dioxide and is as corrosion resistant as possible. Preferably containers made of glass, metal or plastic, especially HDPE, LDPE, PVC, PTFE or mixed polymers, are used. A preferred embodiment of the present invention is the light transparent container for mixing, transporting and/or storing solutions.

In particular, it is possible to calculate that at lower filling rates, for example after partial consumption of the chlorine dioxide solutions of the invention, the container contains more chlorine dioxide in the gas phase than in the liquid. This is also usually the main explanation for the main losses of active substance in chlorine dioxide solutions.where the passage of chlorine dioxide from the liquid to the gas phase depends on the surface of the solution and in particular the free gas space above it. If the surface of an otherwise closed vessel is covered, for example by a floating body more or less closely suspended, the rate of equilibrium of chlorine dioxide in the gas phase to the liquid is considerably reduced. Therefore, the storage and/or transport vessel of the solution of the invention preferably includes a floating vessel. This makes it possible to reduce the surface of the chlorine dioxide at low filling to the extent that the residual pressure of chlorine dioxide remains low and can be safely used.

The pH of the solutions of chlorine dioxide obtained by the method of the invention is in an embodiment of about 2 to about 4 and preferably in the range of about 2.5 to 3. This pH range is particularly advantageous in terms of the stability of the solution of the invention. In contrast, conventional chlorine dioxide solutions usually have a pH value greater than 4, which is achieved by a suitable buffer system. According to an embodiment of the present invention, this solution of chlorine dioxide does not contain a buffer. In a preferred embodiment, this solution of chlorine dioxide does not contain any other component selected from the group consisting of activators, catalysts and stabilizers.

The chlorine dioxide solution obtained by the method of the invention may contain at least one additional radical in addition to chlorine dioxide. It is clear from the sum equation (2) that it is assumed that the conversion of an equivalent chlorite with an equivalent peroxodisulphate will also produce an equivalent hydrogen sulphate radical in addition to an equivalent chlorine dioxide, as described above. Accordingly, the additional radical is preferably a hydrogen sulphate radical or a by-product thereof obtained by reaction with the hydrogen sulphate radical.

Because of the additional radical present in the solution, this chlorine dioxide solution contains another strong oxidizing agent and thus has an additional oxidizing effect which suppresses or reduces autocatalytic decomposition, which gives this chlorine dioxide solution an advantage over conventional chlorine dioxide solutions.

The solution of chlorine dioxide according to the invention can be destroyed in a short time by adding sufficient quantities of sulphite in a simple and safe manner. Adding an aqueous sodium sulphate solution to the solution of chlorine dioxide according to the invention also destroys the chlorine dioxide in the water and air phase instantly. The use of the sulphite solution simplifies the storage, allows the destruction of chlorine dioxide by hand and allows the destruction of chlorine dioxide by hand with the use of high-definition solutions and the elimination of toxic chlorine dioxide by hand.The further advantage of the destruction of chlorine dioxide is that only non-toxic chloride and, in the case of sulphite, non-toxic sulphate is produced. Other The present invention also relates to the use of the aqueous chlorine dioxide solution described above as a disinfectant, oxidizer or bleacher and/or deodorizer. The chlorine dioxide solutions of the invention may be used, for example, for the disinfection of air, soil and water, such as drinking water, bathing water, wastewater, domestic water, etc., in medicine, in filters or biofilms. The chlorine dioxide solutions of the invention may also be used as oxidizers or bleaches, for example, in various technical processes, such as papermaking, food manufacturing, etc., in the processing of waste and sludge, or in sewage treatment.The solutions of chlorine dioxide according to the invention can continue to be used as deodorizers, for example in odor control, such as in a sewage system, in industrial processes, in households, etc., in solids, suspensions and cleaning products. The above applications are not intended to be a complete list, but rather the solutions of chlorine dioxide according to the invention can be used in all appropriate fields where their disinfecting, oxidizing and deodorizing effect is useful. Other The chlorine dioxide solution of the invention can still be used to convert chlorine dioxide from this solution quantitatively into organic solvents by extraction with organic solvents such as ether, hydrocarbons, etc. This makes chlorine dioxide available for further reactions limited to suitable organic solvents.where water is obstructive or counterproductive (e.g. due to corrosion due to humidity, etc.). Other The aqueous chlorine dioxide solution obtained by the method of the invention may also be used for disinfecting drinking and bathing waters or for the treatment of municipal and waste water. Other The aqueous chlorine dioxide solution obtained by the method of the invention can also be used for disinfecting drinking and bathing water, for the treatment of domestic and waste water or for the effective control of biofilms, whereby the solution contains chlorine dioxide together with the hydrogen sulphate radical in the form of a radical pair association. Other The following are again particularly favourable uses of the chlorine dioxide solutions of the invention, which allow the chlorine dioxide solutions of the invention to be used in technical processes.Other Other Exemplary technical processes include non-destructive hygienisation (disinfection) of membrane systems, e.g. RO systems, including in the medical field; moisture removal on all types of materials; coating removal, e.g. on vehicles, ships, aircraft; odor control in production processes; industrial wastewater treatment by disinfection of wastewater, physical-chemical water separation and residual recycling; corrosion protection in wastewater systems; surface water protection of paints, coatings of all types, plastics, wood chemicals, oxides, stones, kerosene; long-term de-oxidation; the removal of internal toxicity (e.g. by disinfection of wastewater, physical-chemical water separation and residual recycling); the use of chemicals or chemicals (e.g. for preserving water, cosmetics, chemicals, chemicals, chemicals or chemicals intended for use as disinfectants); the use of chemicals for the treatment of external air, cosmetics, chemicals, chemicals or chemicals; and the use of chemicals for the treatment of diseases or diseases (e.g. for use as disinfectants, disinfectants or disinfectants);The following substances are to be used:_{2 and}S, NO, NO_{2 and}The chlorine dioxide solutions of the invention can also be used for oxidative treatment of heavy metals.

Furthermore, the chlorine dioxide solutions of the invention may be used for the treatment of drinking water, e.g. in water systems for the permanent disinfection of drinking water, in water supply systems for the permanent disinfection of water pipes, in the form of standby disinfection or in the form of a permanent disinfection, and in the non-chlorination or disinfection of drinking water, e.g. after heavy rain, after germination (e.g. after bacterial contamination of a drinking water reservoir, for the permanent disinfection of groundwater, surface water or sewage and for the removal of pathogenic germs, e.g. sewage pipes, sewage pipes, sewage or sewage disasters, etc.). In this way, chlorine dioxide solutions may be used to effectively prevent the contamination of drinking water, e.g. after heavy rain, after germination (e.g. after bacterial contamination of a drinking water reservoir, after bacterial contamination of groundwater, surface water, surface water, surface water, sewage or sewage) and in the form of a solution for the permanent removal of water from a natural body of water (e.g. a water heater), especially in the form of a solution for the formation of organic carbon monoxide, or other organic compounds, such as chlorine oxide, which may be used in the production of water, in the building or other parts of buildings, buildings, buildings, buildings, buildings, buildings, buildings, buildings, buildings, buildings, buildings, buildings, buildings, etc., etc., and buildings, especially in the building or in the building or in the building or in the building or in which the building, or in which the building, or in which the building is used, or in the building or in the building or in the building, or in the building, or in the building, or in the building or in the building or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building, or in the building,

Other suitable applications in this area are the substitution of emergency disinfection, the disinfection of earth and high-level tanks, the disinfection of fittings and pipelines, the disinfection after rupture of pipes, the disinfection after re-germination, biofilm control and biofilm prophylaxis, the treatment of waste water for drug residues and the elimination of multidrug-resistant germs.

In air conditioning units and cooling towers, the chlorine dioxide solutions of the invention can be used to remove biofilm from heat exchangers and pipelines, to remove germs such as legionella, to perform stand, permanent or impact disinfection and to protect against corrosion.

In food production, the chlorine dioxide solutions of the invention may be used for water treatment of production and rinsing water, hygiene maintenance in the production process, sterilization of transport vehicles, animal husbandry, eradication, control and prevention of infectious agents, and hygiene maintenance in the slaughterhouse, for example during processing, packaging or cleaning.

For fruit and seeds, the chlorine dioxide solutions of the invention may be used to maintain hygiene during the growing phase, during and after harvest, to maintain hygiene during processing, during packaging to extend shelf life, to maintain seed storage hygiene, to prevent seed germination, to disinfect or sterilise with a sustainable effect.

In the case of railways, aircraft or ships, the chlorine dioxide solutions of the invention may be used for the maintenance of sanitary hygiene, air conditioning, odor control, long-term ecological vegetation removal, e.g. of railway areas, signage, etc., for disinfection of ships, waste water treatment, treatment of grey, yellow or black water, disinfection of sewage and for the extraction of drinking water from seawater.

The solution can be used as a surface protection for paint, coatings of all kinds, plastics, wood, metal, ceramics, stone. The solution used is particularly effective with long-term use. The long-term effect is the result of the complete removal of the biofilm from the surface. The solution can also be used to detoxify flies and gases (gases), to maintain the air quality. It can be used for disinfection, disinfection of the oral cavity, disinfection of the oral membrane, as well as for the treatment of diseases, disinfection of the oral cavity.

The present invention also concerns a device for the production of the chlorine dioxide solution described above. This device for the production of the chlorine dioxide solution of the invention is based on the idea that the process of the invention for the production of a chlorine dioxide solution can be carried out not only on a large industrial scale, but also on a smaller scale. Therefore, a device for the implementation of the process of the invention may also be available, for example, in single or multi-family houses, in order to provide there the quantities of chlorine dioxide required, for example, for disinfecting drinking and bathing water.

In this context, the device (1) to produce the chlorine dioxide solution of the invention includes: (a) at least one storage tank for a chlorite component (2), (b) at least one storage tank for a peroxodisulphate component (3), (c) at least one mixing tank (4) connected or capable of being connected to at least one storage tank for a chlorite component (2) by a feed line for the chlorite component (5) and connected or capable of being connected to at least one storage tank for a peroxodisulphate component (6) by a feed line for the peroxodisulphate component (3); (d) at least one storage tank for the chlorine dioxide solution (7) connected or capable of being connected to at least one chlorine dioxide solution (16) by a feed line for the chlorine dioxide component (4); (e) at least one device for the chlorine dioxide solution (18) which is capable of being connected to at least one of the chlorine dioxide solutions (7) and which is located in the body of the chlorine dioxide solution (20), and which is capable of being discharged into the body of the chlorine dioxide solution (20),

The device in accordance with the invention is described below by way of example with reference to the accompanying drawing of a preferred embodiment, since the tasks, characteristics and benefits of the device in accordance with the invention are easier to understand by the following detailed description and the accompanying drawing, which should be understood as meaning that the embodiment presented in the drawing is also represented by merely preferred features which do not necessarily have to be present.

Figure 1 shows a preferred embodiment of the device of the invention for the preparation of a chlorine dioxide solution.

The device 1 includes a reservoir for a chlorite component 2 This reservoir 2 is designed to store the chlorite component, for example, in solid form and as an aqueous solution. In a preferred embodiment of the device of the invention, the reservoir 2 may include a mixing or stirring device 8 so that in the reservoir 2 an aqueous chlorite component can be produced by dissolving solid chlorite in water, facilitated by the mixing or stirring device 8 This dissolution is facilitated by the mixing or stirring device 8 In another preferred embodiment, the reservoir 2 contains a measuring device 9 or more amps, which can measure the concentration or concentration of chlorite in the reservoir 2 for example, or a measuring device suitable for measuring the pH of the oxide or chloride in the solvent, for example, for the measurement of the pH of the solvent, or for the measurement of the amount of chloride in the solvent, for example, for the measurement of the pH of the solvent, or for the measurement of the pH of the solvent.

The device 1 also contains a storage tank for a peroxodisulphate component 3 This storage tank 3 is designed to store the peroxodisulphate component, for example, in solid form and as an aqueous solution. In a preferred embodiment of the device of the invention, the storage tank 3 may include a mixing or stirring device 10 so that in the storage tank 3 an aqueous peroxodisulphate component can be produced by dissolving solid peroxodisulphate in water, facilitated by the mixing or stirring device 10 In a further embodiment, the pre-designed storage tank 3 may contain 11 or more measuring ampere, which may be suitable for determining the concentration or concentration of peroxides in the reservoir 3 or the pH of the lead-sulphate, or for measuring the potential of the peroxide in the reservoir 3

The device 1 shall also include a mixing tank 4 connected or interconnected to at least one storage tank for a chlorite component 2 by a feed line for the chlorite component 5 and a peroxodisulphate component 6 connected or interconnected to at least one storage tank for a peroxodisulphate component 3. The feed lines 5 and 6 shall be set up to deliver the chlorite or peroxodisulphate component from the storage tanks 2 and 3 to the mixing tank 4. In a preferred embodiment, the feed lines 5 and 6 shall be provided with dosing devices 12 and 13 which are set up to supply the peroxodisulphate or peroxodisulphate to be delivered in a fully regulated manner, and in a specific embodiment, the quantity of peroxodisulphate and peroxodisulphate to be delivered shall be regulated in a specific proportional manner, including the amount of peroxodisulphate and peroxodisulphate to be delivered in the feed line 5 and 12 and the amount of peroxodisulphate and peroxodisulphate to be delivered in the feed line 13 and 12 respectively._{2 and}O₈ ^2-[ [ClO]_{2 and} ^{- I 'm not .}] of more than 1 is fed into the mixing tank 4.

The mixing vessel 4 preferably contains a mixing or stirring device 14 designed to mix the chlorite and peroxodisulphate component supplied. Furthermore, the mixing vessel 4 preferably contains one or more measuring cells 15 designed to determine the amount or concentration of chlorine dioxide and/or chlorite and peroxodisulphate in the mixing vessel 4. The corresponding measuring cells 15 allow the tracking of the process of conversion of chlorite and peroxodisulphate to chlorine dioxide. Furthermore, the mixing vessel 4 is preferably designed to allow the water to be supplied in this form. This is particularly important if both are supplied to the mixing vessel 4 in the form of components.

In a preferred embodiment, the device 1 shall comprise at least two reservoirs for chlorine dioxide solution 7a and 7b. The at least one reservoir 4 shall be connected or interconnected with the mixer 4 by at least one supply line 16. The at least one reservoir 7 shall be designed to store the chlorine dioxide solution produced by the containment process until it is needed for the specific application. In a preferred embodiment, the reservoir 7 shall be provided with at least one reservoir 4 equipped with a pressure regulator to discharge chlorine dioxide solution, which is at least 20 m3/s. This is also necessary in the case of the chlorine dioxide reservoir 7 and at least one reservoir 7 with a pressure reservoir 7 in the lower reservoir.

Furthermore, the device 1 of the invention includes a dosing device 18 to which at least one reservoir for chlorine dioxide solution 7 is attached. This dosing device 18 is designed to control the removal of chlorine dioxide solution from at least one reservoir 7. The dosing device 18 may, for example, be a dosing pump. If the device 1 includes at least two reservoirs for chlorine dioxide solution 7a and 7b, it is advantageous that the dosing device 18 is designed so that it can be used to determine the concentration of chlorine dioxide solution 7a or 7b in either reservoir or reservoir. The measuring device 7 includes a pre-filled chlorine dioxide concentration 7 or 7b and can be used to determine the concentration of chlorine dioxide in the reservoir at any time and the amount of chlorine dioxide and/or peroxide in the reservoir.

The device of the invention allows the production and storage of a solution of chlorine dioxide in variable quantities. Storage in at least two different storage vessels 7a and 7b also allows the continuous removal of finished chlorine dioxide solution. For example, during the removal of the solution from storage vessels 7a, the storage vessels 7b can be refilled and vice versa.

In a preferred embodiment, the device of the invention also includes a maturation vessel, which is located between the mixer 4 and the storage vessel 7. This maturation vessel is conveniently arranged to accommodate the solutions combined in the mixer 4 and to accommodate them until the conversion of chlorite and peroxodisulphate to chlorine dioxide is completed. In a particularly preferred embodiment, the maturation vessel also includes a pressure regulator.

Furthermore, the device of the invention preferably includes an automated process control unit, which is connected or interconnected with, for example, the measuring cells 9, 11, 15 and 19, the pressure control devices 17, and the dosing devices 12 and 13, which can, for example, control the amount and concentration of the chlorine dioxide solution to be prepared by controlling the amounts of chlorite and peroxodisulphate to be introduced.

In another preferred embodiment, the device 1 of the invention is designed to produce and store the chlorine dioxide solution in a light-defensive manner, for example by having the containers and supply lines designed to be opaque to light, or by having the device 1 placed in a box or box that is opaque to light.

In another preferred embodiment, the device 1 of the invention is tempered. It is particularly desirable that the device 1 be so designed that, in particular, the mixing of the two starting products and the storage of the finished chlorine dioxide solutions can be carried out at temperatures in the range from about 0°C to about 25°C. This can be done, for example, by suitable cooling devices which cool the individual mixing or storage containers.

In another embodiment, the device 1 is designed to produce the chlorine dioxide solution continuously in a flow-through operation, and in another embodiment, the device 1 is designed to produce the chlorine dioxide solution in batches in a batch operation.

In one embodiment, the device is designed to be used as a small unit in a single or multi-family house, which is useful for providing the quantities of chlorine dioxide required to disinfect drinking and bathing water, for example, continuously or in batches as required. In another embodiment, the device is designed to produce a solution of chlorine dioxide in a transportable manner by being housed in a housing. The housing may be suitable for any transport, for example, a metal or plastic housing. The portable device is preferably a device weighing less than 500 kg, particularly less than 100 kg. This may be the case in a small house or in a multi-family house.

In another preferred embodiment, the device is designed for use as a large-scale industrial plant, e.g. a tank plant, which is advantageous, for example, for producing the chlorine dioxide solution in large quantities and then filling and distributing or transporting it into smaller containers, where appropriate, which has the advantage of not requiring the chlorine dioxide solution to be produced on site.

The invention is now explained in more detail by means of examples.

Examples Analytical report:

The concentration of chlorine dioxide in the chlorine dioxide solutions of the invention may be determined by various measurement methods, in particular by amperometry, photometry, iodometry, titration of the chlorine dioxide solution with a sulphite solution or ion chromatography.

The methods of analysis are described in detail in the worksheets of the German Association of Gas and Water Works (DVGW) W224 (February 2010), page 18ff with reference to DIN 38408-5.

In the following examples, photometry was used in particular to determine the concentration of chlorine dioxide and ion chromatography was used to determine the other components, such as chlorite, chlorate, perchlorate, hypochlorite and chlorine dioxide.

The Lambert-Beer law is fully applicable in photometry, where the concentration of chlorine dioxide is measured at 360 nm. The molar extinction coefficient is 1100+/-50 [1/mol*cm].

Err1:Expecting ',' delimiter: line 1 column 295 (char 294)

Example 1: Production of 60 litres of approximately 0.6% aqueous chlorine dioxide solution

In a 60-litre canister, 56,530 g of demineralized water are weighed. 1970 g of technical 24,5% sodium chlorite solution and 1,500 g of sodium peroxodisulphate (99%ig) are weighed separately in separate containers. The peroxide and chlorite are separately dissolved in a sufficient amount of water from the canister. After the sodium chlorite solution is introduced, the sodium peroxodisulphate solution is poured and left to stand at 12 °C for 24 to 48 hours. The residues of chlorine dioxide are 88 to 98%, depending on the sodium chlorite used.

Example 2: Manufacture of 50 caps per 0,2 litres of approximately 0,6% chlorine dioxide solution

In a 10-litre bucket, weigh 9.65 litres of demineralized water. Weigh separately 100g of powdered 80% sodium chlorite (20% sodium chloride) and 250g of sodium peroxodisulfate (99%). Both solids are dissolved separately with sufficient quantity of water from the bucket. The sodium chlorite solution is added to the remaining water of the bucket and mixed with the peroxide solution after a short stir.

The finished mixture is bottled and stored for 2 to 3 days in a refrigerator at 5 to 10°C. The yield of chlorine dioxide is 85 to 99%, depending on the sodium chlorite used.

Example 3: Production of one litre of 0.3% chlorine dioxide solution

500 mg sodium chlorite (80%ig) is dissolved in 500 ml of demineralized water and mixed with a solution of 2500 mg sodium peroxodisulfate in 497 ml of demineralized water.

Example 4: Preparation of one litre of 0.6% chlorine dioxide solution

10.00 g sodium chlorite (80%ig) are dissolved in 100 ml of demineralized water. 105.00 g sodium peroxodisulfate (99%ig) are also dissolved in 100 ml of demineralized water. Both solutions are given in 685 ml of demineralized water. The bottle is closed and left in a refrigerator for 3 h. The yield is > 95%, based on the sodium chlorite use.

Example 5: Preparation of one litre of 0.6% chlorine dioxide solution

The bottle is closed and left in a refrigerator for 30 minutes. The yield is > 98% depending on the sodium chlorite used.

All solutions of chlorine dioxide produced in examples 1 to 5 were found to be storage stable, i.e. no significant decomposition (> 5%) of chlorine dioxide was observed after one year, and the less by-products present in the reaction mixture, the more stable the solutions were.

The finished product was found to be membrane-bound as a radical pair associate and this radical pair associate has altered physical properties (vapor pressure, solubility, etc.).

The vapour pressure of a 0,6% chlorine dioxide solution was determined as follows: Other

Temperatur [°C]			Gesamtdruck inkl. Wasserdampf [mbar]
10	96	33	5
20	114	41	67
30	147	54	140
40	171	65	185
50	209	82	301

The literature (DVGW W224/1986 p.5) shows that from a CIO onwards, the_{2 and}- a concentration of 100 mbar (= 10 vol.%, 300 g of ClO_{2 and}/m³The solution is therefore not suitable for use in the manufacture of other products.

In contrast, the solutions of the invention were found to be well-managed and to show no propensity to spontaneous decomposition or explosion. Even at high temperatures of 50°C, the product reacts only slowly to chlorate, at temperatures of 80 to 90°C, quickly. The solution is not flammable at any time. This has also been tested with chlorine dioxide concentrations of up to 4.5% by weight.

If solutions with chlorine dioxide concentrations of 0.01 to 4.5% are brought into contact with flammable objects/open fire, these objects will themselves become 4.5% ClO._{2 and}- solutions are removed, but the gas phase decomposes._{2 and}The reaction with the gas phase is not detectable.

List of reference marks

1Device for the preparation of the chlorine dioxide solution according to the invention2Storage container for a chlorite component3Storage container for a peroxodisulphate component4Blending container5Storage container for the chlorite component6Storage container for the peroxodisulphate component7, 7a, 7bStorage container for the chlorine dioxide solution8Blending or R-measuring device9Storage container for a chlorite component10M or R-measuring device11Storage container for a peroxodisulphate component12Dose container for the chlorite component13Dose container for the peroxodisulphate component14M or R-measuring device15M or R-measuring device17M or R-measuring device17M for the chlorine dioxide component18Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device18Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device17Mass measuring device18

Claims (13)

1. Method for the preparation of an aqueous chlorine dioxide solution with a concentration of chlorine dioxide in the range from 0.3 to 4.5% by weight, comprising the steps:

   (a) providing chlorite,

   (b) providing peroxodisulfate,

   (c) combining chlorite and peroxodisulfate in an aqueous system and in a molar ratio of peroxodisulfate to chlorite [S₂O₈ ^2-] / [ClO₂ ^-] of greater than 1 under formation of the aqueous chlorine dioxide solution,

   wherein no additional buffer is added for the preparation of the aqueous chlorine dioxide solution.
2. Method according to Claim 1, wherein the molar ratio between peroxodisulfate and chlorite [S₂O₈ ^2-] / [ClO₂ ^-] is greater than 2.
3. Method according to Claim 1, wherein the molar ratio between peroxodisulfate and chlorite [S₂O₈ ^2-] / [ClO₂ ^-] lies between 1 and 2.
4. Method according to anyone of Claims 1 to 3, wherein chlorite and peroxodisulfate in steps (a) and (b) are provided in solid form or in the form of an aqueous solution, wherein in step (c):

   (c1) both components, if both components are provided in solid form, are dissolved in water before being combined, or

   (c2) both components are introduced into an aqueous solvent in solid form simultaneously or successively, or

   (c3) both solutions are combined, if both components are provided in the form of aqueous solutions, or

   (c4) both components are provided in aqueous solution and are introduced simultaneously or successively into an aqueous solvent,

   in order to prepare the aqueous chlorine dioxide solution.
5. Method according to Claim 4, wherein both peroxodisulfate and chlorite are provided in the form of aqueous solutions, through which the peroxodisulfate solution exhibits a pH-value in the range from about 4 to about 6 and the chlorite solution exhibits a pH-value in the range from about 10 to about 12.
6. Method according to anyone of Claims 1 to 5, wherein the combining of peroxodisulfate and chlorite is carried out at a temperature in the range from about 0°C to about 25°C.
7. Aqueous chlorine dioxide solution, which comprises chlorine dioxide in an amount in the range from more than 0.3 to 4.5% by weight, the pH of the solution lying in the range from 2 to 3 and the solution not containing a buffer.
8. Use of the aqueous chlorine dioxide solution according to Claim 7 as disinfectant, as oxidizing agent or bleaching agent and/or as deodorant.
9. Use according to Claim 8, wherein the chlorine dioxide solution is used in the form of an instant disinfection or in the form of a permanent disinfection for the removal of biofilms, legionella, or other germs in drinking-water lines, air conditioning systems, water treatment plants, boilers or pools.
10. Device (1) for the preparation of the chlorine dioxide solution according to Claim 7, comprising:

    (a) at least one storage container for a chlorite component (2),

    (b) at least one storage container for a peroxodisulfate component (3),

    (c) at least one mixing container (4), which, via a feedline for the chlorite component (5), is connected to or can be connected to the at least one storage container for a chlorite component (2) and which, via a feedline for the peroxodisulfate component (6), is connected to or can be connected to the at least one storage container for a peroxodisulfate component (3),

    (d) at least one storage container for the chlorine dioxide solution (7), which, via at least one feedline for the chlorine dioxide solution (16), is connected to or can be connected to the mixing container (4),

    (e) a metering device (18), which is installed on the at least one storage container for the chlorine dioxide solution (7), and

    (f) a floating body (20) which is adapted to cover the surface of the chlorine dioxide solution in the storage container (7).
11. Device (1) for the preparation of a chlorine dioxide solution according to Claim 10, wherein the device is adapted for use as small-scale plant in a one- or multi-family dwelling or as a large-scale industrial system.
12. Device (1) for the preparation of a chlorine dioxide solution according to Claim 10, wherein the device is adapted in portable fashion by putting it in a housing.
13. Device (1) for the preparation of a chlorine dioxide solution according to anyone of Claims 10 to 12, wherein the feedlines (5) and (6) are provided with metering devices (12) and (13), which are arranged to regulate the amount of chlorite and peroxodisulfate to be fed in in such a way that peroxodisulfate and chlorite are fed to the mixing container (4) in a ratio [S₂O₈ ^2-] / [ClO₂ ^-] of greater than 1.