JPH11189889A - Production of hydrogen peroxide and alkali hydroxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of producing a soln. of hydrogen peroxidehaving a suitable alkali ratio [the molar ratio of (alkali hydroxide)/(hydrogen peroxide)], in the electrolytic production of hydrogen peroxide by-producing alkali hydroxide, by regulating the ratio of both products. SOLUTION: An anolyte contg. sulfuric acid and sodium sulfate is fed to an anode chamber 3 as the main body of an electrolytic cell divided into the anode chamber 3 and a cathode chamber 4 by a cation exchange film 2, and electrolysis is executed. Sulfuric acid and sodium sulfate reslectively form hydrogen ions and sodium ions, and since, in the case the amt. of hydrogen ions is larger, in hydrogen peroxide and sodium hydroxide to be formed in the cathode chamber, the relative amt. of the former increases, and, in the case the amt. of sodium ions is larger, the relative amt. of the latter increases, by adjusting the amounts of sulfuric acid and sodium sulfate to be added, the ratio of alkali in the catholyte can be regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing hydrogen peroxide and alkali hydroxide by using an inorganic acid and an alkali metal salt of an inorganic acid as raw materials. The present invention relates to a method capable of controlling the ratio of hydrogen oxide and alkali hydroxide in producing a mixed solution thereof.

[0002]

BACKGROUND OF THE INVENTION Hydrogen peroxide is a useful basic chemical indispensable in the food, pharmaceutical, pulp, textile and semiconductor industries. Conventionally, hydrogen peroxide is 2
-An alkylanthraquinol is industrially obtained by autoxidation, and a large amount of synthesis is continuously performed by simultaneously reducing the obtained anthraquinol with hydrogen to return to the original anthraquinone. For the purification, complicated operations such as repeated rectification are required, and hydrogen peroxide is unstable and cannot be stored for a long period of time. Therefore, demand for an on-site type hydrogen peroxide production apparatus is increasing. In power plants and factories that use seawater as cooling water, it has been conventionally used to generate hypochlorous acid by directly electrolyzing seawater to prevent organisms from adhering to the inside of the condenser. However, the use of hypochlorous acid is being regulated from the viewpoint of environmental protection. That is, the reaction between hypochlorous acid and organisms and organic substances in seawater prevents the formation of an organic chlorine compound, which causes secondary pollution. On the other hand, it has been reported that when a small amount of hydrogen peroxide is added to the cooling water, there is a good effect of preventing biofouling. There is also a report that the addition of hydrogen peroxide is effective in maintaining the quality of fish farm water.
However, as mentioned above, there are still issues of safety and pollution control accompanying the transportation of hydrogen peroxide.

[0003] Production of hydrogen peroxide using a reduction reaction of oxygen gas has been proposed in the past, and US Patent No. 3,693,749 discloses an electrolytic production apparatus for several types of hydrogen peroxide, and US Patent No. 4,693,749.
No. 384,931 discloses a method for producing an alkaline hydrogen peroxide solution using an ion exchange membrane. U.S. Pat. No. 3,969,201 proposes an apparatus for producing hydrogen peroxide comprising a three-dimensionally structured carbon cathode and an ion exchange membrane. However, in these methods, the amount of alkali essential for the production of hydrogen peroxide increases almost in proportion to the produced hydrogen peroxide, so that the alkali concentration relative to the concentration of hydrogen peroxide obtained becomes too high and the application is limited. Would. Also, U.S. Pat. Nos. 4,406,758, 4,891,107 and 4,457,953 disclose a method for producing hydrogen peroxide using a porous membrane and a hydrophobic carbon cathode, with an alkali ratio (sodium hydroxide / hydrogen peroxide). (Molar ratio) is obtained. However, these methods have disadvantages in that it is difficult to control the amount and speed of the transfer of the electrolyte solution from the anode chamber to the cathode chamber, the management of operating conditions is complicated, and particularly the ratio of generated hydrogen peroxide is not constant. These electrolytic reactions are as follows. Anode _{^{reaction: 2OH - → 1/2 O 2 +}} H 2 0
+ 2e ^- cathodic _{reaction: O 2 + H 2 0 +} 2e - → HO
₂ ^- + OH ^- sodium ions in the anode chamber becomes sodium hydroxide migrate to the cathode chamber, and HO ₂ ^- may exhibit alkalinity becomes NaHO ₂ (sodium peroxide). Theoretically, for one molecule of hydrogen peroxide, NaOH ₂ + H ₂ O →
Since it becomes H ₂ O ₂ + NaOH, two molecules of sodium hydroxide are generated together with the previous NaOH.
OH: H ₂ O ₂ = 2.35: 1, and when an alkali component is added to the cathode chamber in advance, the ratio (weight) of sodium hydroxide further increases. In actual industrial electrolysis, a part of the anodic reaction becomes water electrolysis and hydrogen ions are generated instead of sodium ions, so that the alkali ratio is slightly lowered. However, even with an aqueous solution of hydrogen peroxide having this alkali ratio, the alkali ratio is too high for use in the papermaking industry, for example, for pulp bleaching, and is not suitable for use.

Further, Journal of Electrochemical Societ
y, vol. 130, 1117- (1983) proposes a method for stably obtaining an acidic hydrogen peroxide solution by using sulfuric acid and anion exchange membranes and supplying sulfuric acid to the intermediate chamber. Further, in Vol. 57 of Electrochemistry, p. 1073 (1989), a method of improving performance by using a membrane electrode assembly as an anode is reported. However, these methods require a unit of electric power and have a problem in economy. Jornal of Applied Electrochem.vol.125 (19
95) 613 to 627 report that the use of the membrane electrode assembly satisfies the alkali ratio, but doubles the power consumption. Therefore, at the moment, with low power consumption,
There is no known method for producing a mixed solution of sodium hydroxide and hydrogen peroxide having a low alkali ratio.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for obtaining a mixed solution of hydrogen peroxide and alkali hydroxide having a low alkali ratio or a desired alkali ratio by a simpler method than before.

[0006]

According to the present invention, an anolyte containing an alkali metal is supplied to an anode chamber of a two-chamber electrolytic cell having a cation exchange membrane as a diaphragm, and an oxygen-containing gas is supplied to a cathode chamber. A method of oxidizing water in an anode chamber and obtaining hydrogen peroxide and alkali hydroxide in a cathode chamber, wherein a solution of an inorganic acid and an alkali metal salt of an inorganic acid is used as the anolyte containing the alkali metal. It is also possible to control the ratio of hydrogen peroxide and alkali hydroxide to be produced by adjusting the ratio of the inorganic acid and the alkali metal salt of the inorganic acid. .

Hereinafter, the present invention will be described in detail. In the present invention, an inorganic acid and an alkali metal salt of the inorganic acid supplied as a raw material to the anode chamber are used. Hydrogen ions and alkali metal ions generated from the inorganic acid and the alkali metal salt of the inorganic acid, respectively, and ionized in the anolyte, pass through the cation exchange membrane and reach the cathode compartment. Both ions react with hydroxyl ions generated in the cathode chamber and are converted into water and alkali hydroxide, respectively, and the amounts of water and alkali hydroxide generated are proportional to the hydrogen ions and alkali metal ions. Therefore, the molar ratio of the inorganic acid and the alkali metal salt of the inorganic acid existing in the anode compartment at the beginning of electrolysis is almost directly proportional to the molar ratio of water and alkali hydroxide generated in the cathode compartment. And since the hydrogen peroxide generated in the cathode chamber is not affected by the molar ratio of the inorganic acid and the alkali metal salt of the inorganic acid, increasing the molar ratio of the alkali metal salt of the inorganic acid to the inorganic acid in the anolyte increases the cathode capacity. The molar ratio of sodium hydroxide / hydrogen peroxide (alkali ratio) generated in the chamber increases, while the molar ratio of the alkali metal salt of the inorganic acid to the inorganic acid in the anolyte decreases with the alkali ratio in the cathode chamber. This makes it possible to control the alkali ratio.

The present invention utilizes this principle and intends to obtain a hydrogen peroxide solution having an alkali ratio corresponding to a desired application. However, although the alkali ratio can be controlled in this manner, the neutralization of hydroxyl ions and hydrogen ions occurs in the cathode chamber, so that the electrolyte concentration decreases, the electrolyte resistance increases, and heat generation due to voltage loss increases. And requires cooling. In the present invention, the electrolyte concentration is reduced only in the cathode chamber, and the concentration decrease is made as small as possible. The inorganic acids that can be used in the present invention include hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, phosphoric acid, and the like, and the alkali metal salts of the inorganic acids include sodium salts and potassium salts of these inorganic acids. It is desirable to use sulfuric acid and sulfates. When chloride is used, chlorine or hypochlorous acid is generated by electrolytic oxidation, but when these compounds can be used industrially, it is a preferable raw material. The inorganic acid and the alkali metal salt of the inorganic acid to be used are preferably a combination of hydrochloric acid-sodium chloride and sulfuric acid-sodium sulfate which generate the same anion, but a combination of hydrochloric acid-sodium sulfate is also possible.
Further, two or more compounds may be mixed and used as an inorganic acid or an alkali metal salt of an inorganic acid. Also, a dilute alkali hydroxide may be added to the anolyte. In this case, the concentration of the alkali hydroxide in the catholyte increases, and the maximum value is the theoretical value of NaOH: H ₂ O ₂ = 2.35: 1. .

The molar ratio of the inorganic acid to the alkali metal salt of the inorganic acid in the anolyte is not particularly limited in theory. However, as the concentration of the inorganic acid increases, the current efficiency tends to decrease slightly, but the inorganic acid tends to decrease. If the concentration of the alkali metal salt is increased, the alkali ratio becomes too high as in the conventional case, so it may be appropriately set according to the required alkali ratio and electrolysis conditions. The preferred range of the molar ratio of the inorganic acid to the alkali metal salt of the inorganic acid [(molar concentration of the alkali metal salt of the inorganic acid) / (molar concentration of the inorganic acid)] is 0.05 to 10.0. The electrolytic cell used in the present invention is a two-chamber electrolytic cell partitioned by a cation exchange membrane into an anode chamber and a cathode chamber. The cation exchange membrane is used to produce hydrogen peroxide with high efficiency by preventing the hydrogen peroxide generated in the ion exchange membrane chamber from moving to the anode chamber and being oxidized and decomposed into water and oxygen. In addition, by keeping the concentration of hydrogen peroxide high to reduce the amount of hydrogen peroxide produced, the electric conductivity of the electrolytic solution is kept high, the electrolytic voltage is lowered, and the power consumption is reduced. The cation exchange membrane that can be used is not particularly limited, but it is preferable to use a fluororesin-based membrane having durability against an oxidizing agent such as hydrogen peroxide.A typical cation exchange membrane is manufactured by DuPont. There are perfluorosulfonic acid type membranes such as Nafion 115, 117, 315 and 350 under the trade name.

[0010] An anode is installed on the anode chamber side of the cation exchange membrane. The anode is not particularly limited, and may be determined depending on the liquid property of the electrolytic solution. In the present invention, in order to supply almost the same amount of hydrogen ions to sodium ions from the anode chamber to the cathode chamber, it is desirable that the pH in the vicinity of the anode chamber is acidic. As a suitable anode, platinum as a catalyst, An electrode material mainly composed of a metal such as iridium or ruthenium or an oxide thereof is applied to a corrosion-resistant wire mesh such as titanium, niobium, or tantalum, a sintered body of powder, a sintered body of metal fiber or the like by a thermal decomposition method. And an insoluble metal electrode supported by a resin fixing method, a composite plating method, or the like so that the supported amount is 10 to 500 g / m ² . When the anolyte is alkaline at pH> 12, a metal such as nickel or stainless steel may be used as the anode as it is, but at pH <12, nickel etc. forms a passive layer on its surface. In order to make it difficult to conduct electricity, it is preferable to use the insoluble metal electrode at pH <12 even in the case of alkali. The hydrogen ions generated by the anodic reaction are used to neutralize the alkali component in the cathode chamber, but the ratio of the cations to be transferred changes according to the ratio of the sodium ion concentration to the hydrogen ion concentration. If excess hydrogen ions are concentrated near the membrane, the efficiency of the hydrogen peroxide generation reaction in the cathode chamber decreases. Therefore, to suppress concentration polarization between the anode and the cation exchange membrane,
It is preferable to place them at a distance of 5 mm to facilitate the flow of the electrolyte. If the formation of hydrogen peroxide is not adversely affected, the anode and the cation exchange membrane are preferably brought into close contact to lower the electrolysis voltage. The contact between the anode and the cation exchange membrane may be mechanically bonded in advance, or during electrolysis.
It is sufficient to apply a pressure of about 0.1 to 30 kgf / cm ² .

As a cathode, a gas diffusion cathode is used. The material is preferably made of carbon, and carbon or gold is used as the electrode material. In order to quickly supply and remove the reaction product gas and liquid, it is preferable to disperse a hydrophobic material. In the case of a gas diffusion cathode, a so-called semi-hydrophobic gas diffusion electrode having a hydrophilic reaction layer and a water-repellent gas diffusion layer on both surfaces is desirable. Also, the gas diffusion electrode can be used in close contact with the cation exchange membrane, and the distance between the two can be kept to a minimum, thereby minimizing the electrolysis voltage. However, the generated catholyte is drained through the gas diffusion electrode to the side opposite to the ion exchange membrane,
Further, since the gas is supplied from the liquid drain side, the structure becomes slightly complicated. The gas diffusion electrode and the cation exchange membrane may be brought into close contact with each other mechanically in advance, or a pressure of about 0.1 to 30 kgf / cm ² may be applied during electrolysis. The electrode material of the gas diffusion electrode is desirably carbon or gold which has a high efficiency of the so-called two-electron reaction of hydrogen peroxide generation and is unlikely to decompose hydrogen peroxide. A typical example of such an electrode is ELAT, trade name of E-TEK. This electrode is formed by filling carbon fiber or cloth with carbon such as graphite or carbon black, and using a fluororesin as a water repellent as a medium. And an electrode having a water-repellent layer on one side and a hydrophilic layer on the other side.

In order to further increase the porosity of the electrode material layer, a compound which is decomposed or volatilized by heating, such as alcohol or ethylene glycol, may be added to the paste. Of course, a foaming agent may be added instead of such a decomposable or volatile substance. In order to quickly perform mass transfer of the reaction gas, it is preferable that a hydrophobic material is dispersed and supported on the electrode material layer and the current collector. As the hydrophobic material, pitch fluoride, graphite fluoride, fluororesin and the like are desirable. In particular, the fluororesin is preferably fired at a temperature of 200 to 400 ° C. in order to obtain uniform and good performance. Particle size of powder of fluorine component is 0.005 to 100 μ
m is preferable. It is desirable that the hydrophobic and hydrophilic portions are respectively continuous along the electrode cross-sectional direction. A sheet-like hydrophilic liquid permeable layer made of zirconium oxide or silicon oxide may be provided between the cation exchange membrane and the gas diffusion cathode. This hydrophilic liquid permeable layer prevents gas supply by taking out a catholyte containing a product which is transmitted through the gas diffusion cathode and taken out to the cathode chamber side at the periphery of the hydrophilic liquid permeable layer. This has the function of avoiding the catholyte solution to accumulate in the gas diffusion cathode, performing smooth gas supply and extraction, and also achieving a reduction in the electrolytic voltage.

The optimal electrolysis operation is such that a metal anode and a gas diffusion cathode are brought into close contact with both sides of a cation exchange membrane, an aqueous solution of an inorganic acid and an alkali metal salt of an inorganic acid is supplied to the anode chamber side, and oxygen gas is supplied to the cathode chamber side. The current is supplied at a temperature of 5 to 40 ° C. and the current density is 1 to 50 A / dm ² . In the present invention, the operation may be performed without changing the ratio of the inorganic acid and the alkali metal salt of the inorganic acid in the anolyte, but the concentration ratio of the alkali hydroxide and hydrogen peroxide in the generated catholyte is tracked. When the alkali ratio is larger than a desired value, the alkali ratio may be controlled during the electrolysis operation, such as increasing the amount of the inorganic acid in the anolyte to decrease the alkali ratio.

Next, an electrolytic cell that can be used for producing hydrogen peroxide according to the present invention will be described with reference to the accompanying drawings, but the electrolytic cell that can be used in the present invention is not limited to these.
FIG. 1 is a longitudinal sectional view showing an example of an electrolytic cell that can be used for producing hydrogen peroxide and sodium hydroxide according to the present invention.
The electrolytic cell body 1 is divided into an anode chamber 3 and a cathode chamber 4 by a cation exchange membrane 2, and the cation exchange membrane 2 is provided in the anode chamber 3.
The porous insoluble metal anode 5 such as an expanded mesh is disposed slightly apart from the anode. A gas diffusion cathode 6 is in close contact with the cathode chamber surface of the cation exchange membrane 2, and a cathode current collector 7 is connected to a surface of the gas diffusion cathode 6 opposite to the cation exchange membrane. Reference numeral 8 denotes an anolyte supply port formed in the bottom plate of the anode chamber 3, reference numeral 9 denotes an anolyte and formed oxygen gas outlet formed in the top plate of the anode chamber 3, and reference numeral 10 denotes a supply of oxygen-containing gas formed in the top plate of the cathode chamber 4. A mouth 11 is an outlet for hydrogen peroxide and sodium hydroxide formed in the bottom plate of the cathode chamber 4.

For example, an aqueous solution of sulfuric acid and sodium sulfate is supplied from the anolyte supply port 8 of the electrolytic cell main body 1 having such a configuration, and wet oxygen gas (or pure water and oxygen-containing gas is supplied from the oxygen-containing gas supply port 10). When a current is supplied between the anode 5 and the cathode 6 while supplying (separately), sodium ions and hydrogen ions are generated in the anode chamber, pass through the cation exchange membrane 2 and pass through the cathode chamber 4.
Reach In the cathode chamber, oxygen gas reacts with water vapor contained in the oxygen gas to generate hydrogen peroxide ions and hydroxyl ions. Hydrogen peroxide ions combine with hydrogen ions to generate hydrogen peroxide, and hydroxide ions react with sodium ions to produce sodium hydroxide or hydrogen ions to produce water. In this case, if a small amount of sodium ions permeate from the cation exchange membrane 2 to the cathode chamber 4 and a large amount of hydrogen ions,
The ratio of the latter to the formed sodium hydroxide and water is increased, so that the alkali ratio is reduced and the hydrogen peroxide content is increased. On the other hand, when a large amount of sodium ions permeate from the cation exchange membrane 2 to the cathode chamber 4 and a small amount of hydrogen ions,
The former produces a higher proportion of sodium hydroxide and water, thus increasing the alkali ratio and lowering the relative hydrogen peroxide content. In this case, the sodium ion source and the hydrogen ion source are sulfuric acid and sodium sulfate in the anolyte, respectively.By adjusting the mixing ratio of both when preparing the anolyte, the alkali ratio can be easily controlled, In particular, when the ratio of sodium sulfate is reduced, a mixed solution of sodium hydroxide and hydrogen peroxide having an alkali ratio required for pulp bleaching of about 1 can be obtained. Conversely, if the ratio of sodium sulfate is increased, a solution having an alkali ratio of 2 or more can be produced.

[0016]

EXAMPLES Next, examples of producing hydrogen peroxide and sodium hydroxide by the method of the present invention will be described, but the examples do not limit the present invention.

[0017]

Example 1 A carbon powder (trade name: Vulcan XC-) having an electrode area of 0.2 dm ² , a titanium insoluble electrode carrying an iridium oxide (IrO ₂ ) catalyst as an anode, and a gold catalyst carrying 72) was supported on a porous electrode substrate made of carbon cloth (manufactured by Nippon Carbon Co., Ltd.) using a fluororesin (Mitsui DuPont, 30J) as a binder to form a gas diffusion cathode. This gas diffusion cathode was placed in close contact with Nafion 350 (manufactured by DuPont), which is a cation exchange membrane, and the anode was placed on the opposite side of the cation exchange membrane with a space for liquid flow of 1 mm. Thus, an electrolytic cell as shown in FIG. 1 was constructed. 1M sulfuric acid and 1M in the anode compartment
Of sodium sulfate aqueous solution at a rate of 1 ml per minute,
Pure water was supplied to the cathode chamber at a rate of 0.4 ml / min, and oxygen gas was supplied at a rate of 60 ml / min from an oxygen concentrator (OA-2L). When the temperature was 30 ° C. and the electrolysis was carried out while applying a current of 2 A, the cell voltage was 2.5 V, and 10.2 g / liter of sodium hydroxide and 8.5 g
g / liter of hydrogen peroxide solution (alkaline ratio is 1.
2) was obtained with a current efficiency of 75%.

[0018]

Example 2 The sulfuric acid concentration in the example was 5, 0.5 or
Electrolysis was performed under the same conditions as in Example 1 except that the concentration was changed to 0.1 M, and the alkali ratio and current efficiency of the obtained solution were measured. The results are summarized in Table 1. From Table 1, the sulfuric acid concentration
When the concentration is about 0.1 M, the alkali ratio becomes about 2, and there is no much difference from the conventional hydrogen peroxide production.
When the ratio becomes about 1, the alkali ratio is reduced to about 1, and a mixed solution of hydrogen peroxide and sodium hydroxide, which cannot be produced conventionally, is obtained. However, it is found that the current efficiency is considerably lowered.

[0019]

[Table 1]

[0020]

Example 3 A titanium porous insoluble electrode supporting ruthenium oxide (RuO ₂ ) was used as an anode, and Nafion 117 (manufactured by DuPont) was used as a cation exchange membrane. Example 1 except that an aqueous solution of sodium chloride adjusted to 1N was supplied at 2 ml per minute.
When the electrolysis was carried out under the same conditions as in the above, the cell voltage was 2.7 V, chlorine and hypochlorous acid were generated from the anode at a current efficiency of 90%, and 10 g / l of sodium hydroxide and 8 g from the cathode chamber outlet. Per liter of hydrogen peroxide (alkaline ratio 1.3) was obtained with a current efficiency of 80%.

[0021]

According to the method of the present invention, an anolyte containing an alkali metal is supplied to an anode chamber of a two-chamber electrolytic cell having a cation exchange membrane as a diaphragm, and an oxygen-containing gas is supplied to a cathode chamber. A method of oxidizing water to obtain hydrogen peroxide and alkali hydroxide in a cathode chamber, wherein a solution of an inorganic acid and an alkali metal salt of an inorganic acid is used as the anolyte containing the alkali metal. This is a method for producing hydrogen and alkali hydroxide. In the method of the present invention, an anolyte containing an inorganic acid and an alkali metal salt of an inorganic acid is electrolyzed in the anode chamber to generate hydrogen ions and alkali metal ions, and the water in the cathode chamber is generated by the two ions passing through the cation exchange membrane. It converts acid ions into water and alkali hydroxide. At this time, the amount of water and alkali hydroxide generated in the cathode chamber is determined by the ratio of hydrogen ions and alkali metal ions permeating into the cathode chamber, and thus the alkali ratio is determined. In other words, the ratio of the inorganic acid contained in the anolyte to the alkali metal salt of the inorganic acid determines the alkali ratio. That is, if the ratio of the inorganic acid to the alkali metal salt of the inorganic acid in the initial anolyte is maintained at a predetermined value, hydrogen peroxide having a desired alkali ratio can be obtained in the cathode chamber.

The method of the present invention can control the alkali ratio of the catholyte containing hydrogen peroxide produced by a simple method of simply determining the ratio of the inorganic acid to the alkali metal salt of the inorganic acid in the initial anolyte. This eliminates the need for complicated and expensive methods such as those described above. It is desirable from the viewpoint of cost and efficiency that the inorganic acid and the alkali metal salt of the inorganic acid be sulfuric acid and sodium sulfate, respectively. The cathode in the method of the present invention is preferably a gas diffusion cathode, and a mixed solution of hydrogen peroxide and alkali hydroxide having a predetermined alkali ratio can be obtained in the cathode chamber. Further, in the method of the present invention, the alkali ratio of the generated catholyte is checked with time, and when the alkali ratio deviates from the desired alkali ratio, the alkali ratio is increased or decreased by increasing or decreasing the amount of the inorganic acid or the alkali metal salt of the inorganic acid. It can be controlled to a predetermined value.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of an electrolytic cell that can be used for producing hydrogen peroxide according to the present invention.

[Explanation of symbols]

1 ・ ・ ・ Electrolyzer main body 2 ・ ・ ・ Cation exchange membrane 3 ・ ・
・ Anode room 4 ・ ・ ・ Cathode room 5 ・ ・ ・ Insoluble metal anode
6 ... Gas diffusion cathode 7 ... Cathode current collector 8 ... Anolyte supply port 9 ... Anolyte and generated oxygen gas outlet 10 ... Oxygen-containing gas supply port 11 ... Peroxidation Hydrogen and sodium hydroxide outlet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Yoshiyuki Kawaguchi, Inventor 1-21-3, 502, Shonandai, Fujisawa-shi, Kanagawa Prefecture (72) Takayuki Shimune, 3006-30, Motomachida, Machida-shi, Tokyo

Claims (4)

[Claims] An anolyte containing an alkali metal is supplied to an anode chamber of a two-chamber electrolytic cell having a cation exchange membrane as a membrane, and an oxygen-containing gas is supplied to a cathode chamber to oxidize water in the anode chamber. A method for obtaining hydrogen peroxide and alkali hydroxide in a cathode chamber, wherein a solution of an inorganic acid and an alkali metal salt of an inorganic acid is used as the anolyte containing the alkali metal, wherein the hydrogen peroxide and the alkali hydroxide are used. Manufacturing method. 2. The method according to claim 1, wherein the inorganic acid and the alkali metal salt of the inorganic acid are sulfuric acid and sodium sulfate, respectively. 3. The method according to claim 1, wherein the gas diffusion cathode is installed in the cathode chamber in close contact with the ion exchange membrane. 4. An anolyte containing an alkali metal is supplied to an anode chamber of a two-chamber electrolytic cell having a cation exchange membrane as a diaphragm, and an oxygen-containing gas is supplied to a cathode chamber to oxidize water in the anode chamber. A method of obtaining hydrogen peroxide and alkali hydroxide in a cathode chamber, wherein a solution of an inorganic acid and an alkali metal salt of an inorganic acid is used as an anolyte containing the alkali metal, and an alkali metal salt of the inorganic acid and the inorganic acid. A method for producing hydrogen peroxide and alkali hydroxide, comprising controlling the ratio of hydrogen peroxide and alkali hydroxide produced by adjusting the mixture ratio of the above.