JP4368166B2 - Fuel cell reactor - Google Patents

Description

  The present invention relates to a fuel cell reactor and a method for producing a compound using the same, particularly hydrogen peroxide.

As a conventional method for producing hydrogen peroxide, for example, (I) an auto-oxidation method using alkylanthraquinone (see Non-Patent Document 1), (II) an electrolysis method in which oxygen is cathodically reduced in an alkali metal hydroxide ( Patent Document 1), (III) a method of catalytically reacting hydrogen and oxygen using a platinum group catalyst suspended or dissolved in sulfuric acid or hydrochloric acid aqueous solution (see Patent Document 2) is known. It is well known that the method (I) is mainly used industrially.
However, in these conventionally known methods, for example, the method (I) requires the addition of a large amount of an organic solvent, and many by-products and catalysts are deteriorated. There are economical disadvantages such as requiring a regeneration process, and development of a cheaper manufacturing method is required. Further, the method (II) has a problem of requiring expensive power energy. Furthermore, in the above method (III), it is necessary to mix hydrogen and oxygen in the same reactor, which has safety problems such as explosion risk, and has a difficulty as an industrial production method.

  On the other hand, in recent years, research for producing various useful compounds under mild conditions using a fuel cell system has been underway. A fuel cell is a system whose purpose is to completely burn electrochemically with fuel separated by an electrolyte membrane, and to directly convert the free energy change of the reaction process into electric power energy. That is, the electron emission reaction and the acceptance reaction are performed at the anode and the cathode, respectively, and the movement of the electrons through the external circuit connecting both electrodes is used as electric power. When such a fuel cell is regarded as a chemical reactor from the standpoint of organic synthesis, it is possible in principle to produce useful compounds together with electric power. A chemical synthesis method using a fuel cell system has advantageous characteristics in industrial production as described in 1) to 4) below. 1) Since active species can be separated and a special reaction field can be formed, a selective reaction that is difficult in a normal catalytic reaction is enabled. 2) The reaction rate and selectivity can be easily controlled electrically. 3) If a load is placed on an external circuit, power can be obtained together with the intended compound. 4) Since an oxidizing substance such as oxygen and a reducing substance such as hydrogen are separated by a diaphragm, the risk of explosion can be reduced.

Examples of application of the fuel cell system to chemical synthesis include (IV) partial oxidation reaction of ethylene and propylene (see Non-Patent Document 2), (V) hydroxylation reaction of benzene (see Non-Patent Document 3), (VI) An oxidative carbonylation reaction of methanol (see Non-Patent Document 4) has been proposed.
The inventors of the present invention have previously proposed (VII) a method for producing hydrogen peroxide from hydrogen and oxygen (see Non-Patent Document 5) by applying a fuel cell system. In this method, Nafion (registered trademark of DuPont) is used as a diaphragm, platinum black is used as the anode side of the membrane, gold mesh or graphite is used as the catalyst electrode on the cathode side, and hydrogen gas and hydrochloric acid aqueous solution are introduced into the anode chamber. Hydrogen peroxide is produced by blowing oxygen gas into the chamber. However, although this method has the advantages 1) to 4) and the like, the concentration of the obtained hydrogen peroxide is low, and the production of hydrogen peroxide reaches its peak over time.

In order to improve such problems, the present inventors have proposed a method for producing hydrogen peroxide composed of hydrogen and oxygen using a fuel cell reactor having a new structure (see Patent Document 3). . This method is divided into an anode chamber, an intermediate chamber, and a cathode chamber by an anode and a cathode, an electrolyte solution is present in the intermediate chamber, and a device having a structure in which both electrodes are externally short-circuited by an electronic conductor or the intermediate chamber is a cation. In this method, hydrogen is generated in the electrolyte solution in the intermediate chamber by supplying hydrogen to the anode chamber and oxygen to the cathode chamber using an apparatus having a structure partitioned by an exchange membrane. However, with this method, the production rate of hydrogen peroxide is dramatically improved, but it is not always satisfactory in terms of the accumulated concentration of hydrogen peroxide.
In the chemical industry, not only these hydrogen peroxide production methods but also the development of reaction methods and catalysts for producing useful chemicals more efficiently is always required.

See US Pat. No. 4,431,494, etc. See US Pat. No. 4,009,252, etc. JP 2001-236968 A Chemical Handbook, Applied Chemistry I, The Chemical Society of Japan, 302, 1986 Catalyst, 31, 48, 1989 J. et al. Chem. Soc. Faraday Trans. , 90, 451, 1994 Electrochimica Acta, Vol. 39, no. 14, 2109, 1994 Electrochimica Acta, Vol. 35, no. 2,319,1990

  It is an object of the present invention to produce useful chemicals in mild conditions with high selectivity, in an efficient and economical manner and to produce electricity as needed to overcome the problems of conventional catalytic processes. Providing a fuel cell type reactor capable of performing the same, and using the fuel cell type reactor, providing an efficient and economical method for producing useful chemicals under mild conditions with high selectivity, In particular, by using the reaction apparatus to produce hydrogen peroxide from hydrogen and oxygen, the use of a large amount of organic solvent in the conventional production method, the complexity of the production process, the large consumption of power energy, the hydrogen and oxygen consumption. It is to solve problems such as explosion hazard due to mixing and low hydrogen peroxide yield.

As a result of intensive studies to solve the problems of the prior art, the present inventors have reached the following present invention.
That is, the present invention
[1] A fuel cell type reaction apparatus for performing a redox reaction of a system containing a reducing substance and an oxidizing substance, which is divided into an anode chamber, an intermediate chamber, and a cathode chamber by an anode and a cathode, The anode-side intermediate chamber and the cathode-side intermediate chamber located between the anode and the anion-exchange membrane and between the cathode and the anion-exchange membrane by an anion exchange membrane, respectively. An alkaline electrolyte solution is introduced into the intermediate chamber, the anode-side intermediate chamber has an electrolyte solution inlet, the anode chamber has a reducing substance inlet, and the cathode chamber has an oxidizing substance inlet. A fuel cell type reaction apparatus comprising: an anode; and a cathode connected to each other by an electronic conductor on the outside.
[2] The fuel cell type reactor according to [1], wherein the cathode-side intermediate chamber has an inlet for an electrolyte solution.
[3] The anode-side intermediate chamber has a structure in which an inlet for supplying an alkaline electrolyte solution and a discharge port for the alkaline electrolyte solution are installed, and the alkaline electrolyte solution is continuously supplied to the anode-side intermediate chamber The fuel cell type reactor according to [1] or [2] above, wherein

[4] The fuel cell type reactor according to any one of [1] to [3], wherein the cathode is a catalyst electrode containing a conductive carbon material.
[5] The fuel cell reactor according to the above [4], wherein the conductive carbon material is one or more carbon materials selected from activated carbon, carbon fiber, graphite, carbon whisker, carbon black, and acetylene black.
[6] The fuel cell reactor according to any one of [1] to [5], wherein the alkaline electrolyte solution is an aqueous solution containing sodium hydroxide.
[7] A method for producing a compound by oxidation-reduction reaction, using the fuel cell type reactor according to any one of [1] to [6] above, introducing a reducing substance into the anode chamber, and oxidizing the cathode chamber A method for producing a compound comprising introducing a reducing substance and obtaining the compound from the reducing substance and the oxidizing substance in a cathode-side intermediate chamber.
[8] The method for producing a compound according to [7] above, wherein the reducing substance is a hydrogen donor, the oxidizing substance is oxygen gas, and the produced compound is hydrogen peroxide.

According to the present invention, it is possible to overcome problems of conventional oxidation processes such as low yield and selectivity of the target compound, complicated manufacturing process, and large consumption of energy.
By using the fuel cell type reactor of the present invention, a useful chemical substance can be produced under a mild condition with a high selectivity, a high efficiency and an economical method, and electric power can be obtained as a by-product if desired. Can do. In addition, since the reaction can be performed in a state where the reducing substance and the oxidizing substance are separated from each other at the anode and the cathode, the danger of explosion due to the formation of an explosion mixture can be avoided, and the product and the oxidation product are sequentially detected. The production of by-products due to a typical reaction can be suppressed, and the reaction activity and reaction selectivity are high. As shown in the examples, by using the reaction apparatus of the present invention, hydrogen peroxide can be produced from hydrogen and oxygen under mild conditions with high selectivity and high efficiency, and electric energy is obtained as necessary. You can also.

  Hereinafter, the details of the present invention will be described using a method for producing hydrogen peroxide as an example. Of course, the present invention is not limited to the method for producing hydrogen peroxide, and is effective for other chemical synthesis reactions to which the fuel cell system such as (IV) to (VI) described in the prior art can be applied. It will be something. FIG. 1 is a schematic diagram showing the principle of a reaction for producing hydrogen peroxide from a reducing substance (hydrogen) and an oxidizing substance (oxygen) by the method of the present invention using the fuel cell type reactor of the present invention. Show. The apparatus shown in FIG. 1 has a three-tank structure having an intermediate chamber formed between the inside of the anode 4 and the inside of the cathode 5, the anode chamber 1 outside the anode 4, and the cathode chamber 3 outside the cathode 5. The intermediate chamber is further partitioned by the anion exchange membrane 12 into a cathode-side intermediate chamber 2A and an anode-side intermediate chamber 2B. An alkaline electrolyte solution is introduced into the intermediate chamber (2A, 2B). The anode chamber 1 has a reducing substance inlet 6 for supplying a reducing substance and a reducing substance outlet 14, and the cathode chamber 3 has an oxidizing substance inlet 7 for supplying an oxidizing substance. And an outlet 15 for oxidizing substances. The anode side intermediate chamber 2B has an alkaline electrolyte solution inlet 11 and an alkaline electrolyte solution outlet 13, and the cathode side intermediate chamber 2A can be provided with an alkaline electrolyte solution inlet 8 as desired. At that time, when the cathode side intermediate chamber 2A does not have the inlet 8 for the alkaline electrolyte solution, the cathode side intermediate chamber 2A contains the alkaline electrolyte solution (for example, the electrolyte aqueous solution is covered with an ion exchange membrane). The reactor is provided in a confined state. When the electrolyte solution containing the generated hydrogen peroxide is extracted from the intermediate chamber, the hydrogen peroxide may be extracted using the inlet 8.

  2 and 3 are a partially exploded perspective view and a longitudinal sectional schematic view of the apparatus used in Example 1 as an example of the fuel cell type reaction apparatus of the present invention, respectively. 2 and 3, a current collecting metal mesh (for example, gold mesh) 21 is attached to the outer surfaces of the anode 4 and the cathode 5, and the outer surfaces of the anode 4 and the cathode 5 are electronic conductors. Are connected to each other by lead wires 9. If desired, the reaction can be promoted by providing a constant voltage generator between the anode 4 and the cathode 5 and applying a voltage. If desired, power can also be extracted from the operating device of the present invention by applying a load to the external circuit. In addition, in the example of the apparatus of the present invention shown in FIGS. 2 and 3, in addition to the members indicated by the numbers 1 to 15 and 21 described above, a Teflon (registered trademark) presser plate A22 and Teflon for pressing the electrodes are used. A (registered trademark) presser plate B23, a Teflon (registered trademark) spacer 24 having a cathode side intermediate chamber 2A inside, and a silicon spacer 25 having an anode side intermediate chamber 2B inside.

  The anode used in the present invention is made of an anode active material serving as a catalyst and has ionic conductivity or active species conductivity. In addition, the cathode used in the present invention is made of a cathode active material serving as a catalyst and has ionic conductivity or active species conductivity. Here, the “active species” means a reactive chemical species derived from a reducing substance, and means an anode that passes through the anode from the anode chamber toward the intermediate chamber. The cathode is a reactive chemical species derived from an oxidizing substance and means a substance that passes through the cathode from the cathode chamber side toward the intermediate chamber. In the present invention, various materials can be used as the anode active material and the cathode active material, and those containing at least one or more selected from various metals, metal compounds, and conductive carbon materials are usually used. Can be used. The metal used as the anode active material and the cathode active material is preferably a metal selected from Groups 1 to 16 of the periodic table. These metals may be used alone or as a mixture of two or more. In addition, compounds such as inorganic compounds and organometallic compounds of these metals are used, but preferably metal halides, metal oxides, metal hydroxides, metal nitrates, metal sulfates, metal acetates, metal phosphates Metal carbonyl, metal acetylacetonate and the like can be used as the metal compound. In addition, as the conductive carbon material used as the anode active material or the cathode active material, various carbon materials having electrical conductivity can be used, but carbon such as activated carbon, carbon black, acetylene black, graphite, carbon fiber, carbon whisker, etc. A material is preferably used, and more preferably a carbon material such as activated carbon, carbon fiber, graphite, carbon whisker, or carbon black. These carbon materials may be used alone or as a mixture of two or more.

In the present invention, when hydrogen is used as the reducing substance, a known catalyst for making hydrogen into a proton as the anode active material, for example, a metal selected from Group 8 to 10 in the periodic table, preferably A metal such as Ni, Pt, or Pd or a compound thereof is used. Further, as the cathode active material, the above-described conductive carbon material having electrical conductivity, preferably a carbon material selected from activated carbon, carbon fiber, graphite, carbon whisker, and carbon black, is used alone or as a mixture of two or more. Used.
In the case where the conductivity of the active material is insufficient, the anode and the cathode may include a conductive carbon material for the purpose of increasing the conductivity rather than as a catalyst. For example, when a metal and / or compound thereof as an electrode active material is used in combination with a conductive carbon material added for the purpose of increasing conductivity, it is uniformly mixed with the particulate conductive carbon material, It is preferable to use particles in which a metal and / or a compound thereof is supported on a particulate conductive carbon material because an anode and a cathode having a uniform composition and good electron conductivity can be obtained. As the conductive carbon material, those described above are used.

The composition of the anode active material and the cathode active material used in the apparatus of the present invention has been described above. When a metal and / or a compound thereof is used in combination with a conductive carbon material as an electrode, the total weight of both is used. The ratio of the former weight (in metal conversion) to 0.01 is preferably 0.01 to 50% by weight, and more preferably 0.1 to 30% by weight.
The periodic table referred to in the present invention is a periodic table defined by International Pure and Applied Chemistry Union Inorganic Chemical Nomenclature (1989).
When hydrogen peroxide is produced from hydrogen and oxygen by the method of the present invention as will be described later, an electrode containing platinum black and carbon fiber is preferably used as the anode (in this case, carbon fiber is It is added for the purpose of increasing conductivity, not as an active material). In addition, you may use the easily available electrode generally used with the fuel cell. Further, as the cathode, it is preferable to use an electrode in which the above conductive carbon material is used alone or as a mixture of two or more kinds (the carbon material in this case plays a role as an active material).

  The anode and cathode described above are preferably used by mixing a water repellent agent in addition to the main components described above. In this case, examples of the water repellent include polytetrafluoroethylene (PTFE), tetrafluoroethylene oligomer (TFEO), fluorinated graphite ((CF) n), and fluorinated pitch (FP). In the present invention, these water repellents are electrochemical at the three-phase interface of gas (reducing substance, oxidizing substance), liquid (electrolyte solution) and solid electrode (anode, cathode) in a gas-liquid-solid. It has the effect of improving reaction efficiency. Moreover, since these water repellents also function as a binder for catalyst particles, they can be molded into a sheet shape and used as an electrode by physical mixing with the above components and hot pressing. The amount of water repellent used can be 1 to 250% by weight, preferably 25 to 100% by weight of the electrode active material used.

  As the anion exchange membrane used in the present invention, any one of hydrocarbon-based and fluororesin-based ion exchange membranes can be used. The anion exchange membrane used in the present invention may come into contact with a high concentration alkaline aqueous solution. Therefore, it is preferable to use a high-concentration alkali-resistant fluororesin ion exchange membrane, but even a hydrocarbon ion exchange membrane can be used without any problem in operation for several months. In the case of operation for one year or longer, it is preferable to use a fluororesin-based ion exchange membrane. Examples of the hydrocarbon-based anion exchange membrane that can be used in the present invention include Aciplex (registered trademark) A-201, 211, and 221 manufactured by Asahi Kasei Co., Ltd., and examples of the fluororesin-based anion exchange membrane include Tosoh Corporation. For example, Tosflex (registered trademark) IE-SF34 is available.

  As the electrolyte solution used in the present invention, an alkaline electrolyte solution is used. As the alkaline electrolyte solution, for example, a solution containing sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia or the like may be used alone or as a mixture of two or more. As the solvent for dissolving the alkaline electrolyte, water or a nonaqueous solvent such as alcohol, methylene chloride, chloroform, acetic acid, acetonitrile, or a mixture thereof is used. Preferably, an aqueous solution containing sodium hydroxide is used as the electrolyte solution. The electrolyte concentration in the alkaline electrolyte solution in the present invention may be 0.1 to 80% by weight, preferably 0.5 to 50% by weight.

  As a method for supplying the alkaline electrolyte solution, the alkaline electrolyte solution is introduced in advance from the electrolyte solution inlet 8 provided in the cathode side intermediate chamber 2A as desired in advance and the electrolyte solution inlet 11 provided in the anode side intermediate chamber 2B. After that, a method is used in which a reducing substance is supplied to the anode chamber and an oxidizing substance is supplied to the cathode chamber to perform the reaction. Further, when the alkaline electrolyte solution is continuously supplied to the anode-side intermediate chamber, as described above, the anode-side intermediate chamber 2B is provided with the alkaline electrolyte solution inlet 11 and the alkaline electrolyte solution outlet 13 so that the intermediate The alkaline electrolyte solution may be continuously supplied by upflow from the lower part of the chamber to the upper part, or the alkaline electrolyte solution may be continuously supplied by downward flow from the upper part to the lower part. The method is not particularly limited. The flow rate when the alkaline electrolyte solution is continuously supplied can be appropriately selected according to the scale of the reaction apparatus, but is usually 0.1 ml / hour to 100,000 ml / hour, preferably 0.5 ml / hour to 1000 ml / hour. can do.

As the reducing substance used in the present invention, a compound having an electron donating ability, preferably a hydrogen donor capable of releasing protons and electrons on the anode is used. Specific examples include hydrogen, alcohols, hydroquinones, and saturated hydrocarbons. More preferably, industrially inexpensive hydrogen is used. These hydrogen donors may be used as a mixed gas with an inert gas such as nitrogen, helium, or argon.
The oxidizing substance used in the present invention is not particularly limited as long as it is a compound having an electron accepting ability. Examples thereof include air, oxygen, and nitric oxide. Air or oxygen is preferably used. Further, these oxidizing substances are not necessarily pure, and may be a mixture with an inert gas such as nitrogen, helium, or argon.

In the method of the present invention, various conditions that vary with the scale of the reaction apparatus (for example, the supply amount of the reducing substance, the oxidizing substance, and the electrolytic solution) can be appropriately selected according to the scale of the reaction apparatus.
When the reducing substance and the oxidizing substance are supplied to the anode chamber or the cathode chamber, the respective flow rates can be appropriately selected according to the scale of the reaction apparatus, but the respective flow rates are usually 0.1 ml / min to 100000 ml. / Min, preferably 1 ml / min to 1000 ml / min.
In the method of the present invention, the reaction can be accelerated by applying a voltage between the anode and the cathode. The voltage in the case of applying a voltage can be 0.1-10V normally, Preferably it can be 0.2-2V.

As reaction conditions in the method of the present invention, the reaction temperature is usually selected from the range of -20 to 200 ° C, preferably -5 to 150 ° C. Moreover, the pressure of the reducing substance and the oxidizing substance during the reaction can be carried out at normal pressure, but can be carried out under pressure or under reduced pressure as desired. In the case of carrying out under pressure, the pressure can be over normal pressure and not more than 100 atm. When carried out under reduced pressure, the pressure can be made 10 ⁻² Torr or more under normal pressure. The reaction time may be selected as appropriate by determining a substantial target value of the selectivity and yield of the reactive organism, and is not particularly limited, but is usually several seconds to several hours.
Moreover, as a reaction format, it can carry out batchwise or continuously, and it does not restrict | limit in particular. When the reaction is continuously performed, an appropriate apparatus may be used in combination, and the electrolyte solution may be continuously introduced into the cathode-side intermediate chamber while continuously extracting the reaction mixture formed in the cathode-side intermediate chamber. Specifically, for example, a new electrolyte solution outlet may be installed in the cathode-side intermediate chamber, the electrolyte solution may be continuously introduced from the inlet 8, and the reaction mixture may be continuously extracted from the outlet. .

The reaction product can be separated from the reaction mixture in the reactor by a conventional means such as distillation or extraction by a known separation means to obtain a desired purity. The size of the reactor is not particularly limited. For example, the volume of the intermediate chamber can be selected from a range of about 1 cm ³ to about 10 m ³ , and the volumes of the cathode chamber and the anode chamber are adjusted accordingly. can do.
Next, the present invention will be described by taking as an example a reaction for producing hydrogen peroxide from hydrogen and oxygen. In this case, the reaction shown in the following formulas (1) and (2) is formed by a gas-liquid-solid formed by a gas (hydrogen, oxygen), a liquid (alkali electrolyte solution), and a solid electrode (anode 4, cathode 5). It proceeds at the three-phase interface.
H ₂ + 2OH ⁻ → 2H ₂ O + 2e ⁻ (1)
O ₂ + H ₂ O + 2e ⁻ → HO ₂ ⁻ + OH ⁻ (2)

That is, hydrogen as a hydrogen donor supplied to the anode 4 reacts with hydroxide ions on the electrode to release water and electrons (formula (1)), and the electrons pass through an external circuit to the cathode 5. Moving. At the cathode 5, the supplied oxygen reacts with electrons and water to obtain hydrogen peroxide (hydroperoxyanion) and hydroxide ions as products (formula (2)). The hydroxide ions pass through the anion exchange membrane 12, move from the cathode side intermediate chamber 2A to the anode side intermediate chamber 2B, and are supplied as a reaction raw material of the formula (1).
Since the apparatus of the present invention supplies a reducing substance and an oxidizing substance as gas, each substance is compared with the conventional fuel cell reactor described in (IV) to (VII) described in the background art section. It is possible to increase the activity of the reaction, and there is an effect that the reaction activity and reaction selectivity are improved. As described above, when the above apparatus is used, the chemical species having reactivity move to the three-phase interface inside both the anode 4 and the cathode 5. For this reason, in the present invention, both the anode and the cathode are required to be ion-conductive or active species-conductive. The above reaction principle is essentially the same not only in this hydrogen peroxide production method but also in other various oxidation reactions.

Next, the present invention will be described in more detail with reference to examples and comparative examples.
[Example 1]
In Example 1, hydrogen peroxide was produced from oxygen and hydrogen using the fuel cell reactor shown in FIGS. This reactor comprises a three-tank structure having an intermediate chamber formed between the inside of the anode 4 and the inside of the cathode 5, the anode chamber 1 outside the anode 4, and the cathode chamber 3 outside the cathode 5. Further, the intermediate chamber is partitioned by the anion exchange membrane 12 into a cathode side intermediate chamber 2A and an anode side intermediate chamber 2B. As anion exchange membrane 12, Aciplex A-211 (circular, thickness: 430 to 480 μm, diameter: about 25 mm, manufactured by Asahi Kasei Co., Ltd.) was used. The anode side intermediate chamber 2B is provided with an inlet 11 and an outlet 13 for an alkaline electrolyte solution. The cathode side intermediate chamber 2A is provided with an inlet 8 for an alkaline electrolyte solution. Into the anode side intermediate chamber and the cathode side intermediate chamber, 1.2 ml each of 2N sodium hydroxide aqueous solution was introduced as an alkaline electrolyte solution from the inlet 11 and the inlet 8. The anode chamber 1 has a reducing substance (hydrogen) inlet 6 and a surplus reducing substance outlet 14. The cathode chamber 3 has an inlet 7 for oxidizing material (oxygen) and a discharge port 15 for excess oxidizing material. A gold mesh 21 for current collection is disposed on the anode 4 and the cathode 5, and is short-circuited via an ammeter 10 by a gold lead wire 9.

  The production method of the anode 4 and the cathode 5 is as follows. The anode 4 was prepared by mixing 20 mg of platinum black powder (manufactured by Wako Pure Chemical Industries, Ltd.), 70 mg of carbon fiber powder (manufactured by Showa Denko KK) and 7 mg of PTFE powder (Daikin Kogyo Co., Ltd.). A sheet (thickness: about 1 mm, diameter: about 25 mm) was formed by molding at 120 ° C. using a hot plate (TOP-15 manufactured by ADAVANTEC), a stainless steel plate, and a stainless steel roller. The cathode 5 is a mixture of 70 mg of carbon fiber powder (manufactured by Showa Denko KK) and 7 mg of PTFE powder (Daikin Kogyo Co., Ltd.). It was obtained by molding at 120 ° C. using a stainless roller. The thus obtained sheet-like anode 4 and cathode 5 are attached at an interval of 10 mm to form the cathode side intermediate chamber 2A, the anode side intermediate chamber 2B, the anode chamber 1 and the cathode chamber 3, and are arranged on both electrodes. The gold lead wire 9 connected to the electric gold mesh 21 was short-circuited through the ammeter 10 outside the reaction apparatus.

The reaction was carried out using the above reaction apparatus as follows. The alkaline electrolyte solution (2N aqueous sodium hydroxide solution) introduced into the anode-side intermediate chamber 2B is continuously supplied at 1.5 ml / hour, hydrogen gas is supplied to the anode chamber 1 and oxygen gas is supplied to the cathode chamber 3 at normal pressure. The reaction was conducted at a flow rate of 20 ml / min, with a reaction temperature of 25 ° C. and a reaction time of 2 hours. As a result, generation of hydrogen peroxide was observed in the sodium hydroxide aqueous solution in the cathode-side intermediate chamber 2A, and at the same time, generation of current was also observed. During this time, the potential difference between the anode 4 and the cathode 5, the current and the amount of electricity flowing between the two electrodes were respectively measured by a potentiometer (ELECTRONMETERHE-104 manufactured by Hokuto Denko), a non-resistance ammeter (ZEROSHUNTM METERHM-104 manufactured by Hokuto Denko) and The measurement was performed using a coulomb meter (COULOMMETERHF-210 manufactured by Hokuto Denko). The concentration of the generated hydrogen peroxide was analyzed using a KMnO ₄ aqueous solution.
The concentration of hydrogen peroxide obtained was 8.5% by weight, the rate of formation was 0.813 mmol · cm ⁻² · h ⁻¹ , the current efficiency was 70.0%, and the current density was 62.3 mA · cm ⁻² . there were. The current efficiency was obtained by measuring the amount of electricity that flowed using a non-resistance ammeter and a coulomb meter, and using the following equation.
Current efficiency = (hydrogen peroxide accumulation amount (mol) × 100 / (amount of electricity flowed (C) / 96500 (C / mol))
The quantity of electricity in the equation is a value obtained by converting the measured coulomb value (Q) into an average current value (I (A) = Q (C) · 3600 (S)).

[Example 2]
The reaction was performed in the same manner as in Example 1 except that the alkaline electrolyte solution (2N aqueous sodium hydroxide solution) was not continuously supplied to the anode-side intermediate chamber 2B. The production concentration of hydrogen peroxide was 6.3% by weight, the production rate was 0.533 mmol · cm ⁻² · h ⁻¹ , the current efficiency was 70.5%, and the current density was 40.8 mA · cm ⁻² .
[Example 3]
The reaction was performed in the same manner as in Example 1 except that Aciplex A-201 (circular, thickness: 150 to 230 μm, diameter: about 25 mm, manufactured by Asahi Kasei Co., Ltd.) was used as the anion exchange membrane. As a result, the production concentration of hydrogen peroxide was 7.1 wt%, the production rate was 0.806 mmol · cm ⁻² · h ⁻¹ , the current efficiency was 64.3%, and the current density was 67.2 mA · cm ⁻² . there were.

[Example 4]
The reaction was performed in the same manner as in Example 1 except that Aciplex A-221 (circular, thickness: 130 to 190 μm, diameter: about 25 mm, manufactured by Asahi Kasei Co., Ltd.) was used as the anion exchange membrane. As a result, the production concentration of hydrogen peroxide was 6.8% by weight, the production rate was 0.808 mmol · cm ⁻² · h ⁻¹ , the current efficiency was 65.1%, and the current density was 66.5 mA · cm ⁻² . there were.
[Example 5]
A cathode mixed with 70 mg of carbon fiber powder (manufactured by Showa Denko KK), 10 mg of carbon black (XC72 manufactured by CBOT CORPORATION) and 7 mg of PTFE powder (Daikin Industries, Ltd.) as the cathode was the same as in Example 1. The reaction was carried out in the same manner as in Example 4 except that what was obtained by molding at 120 ° C. using a stainless steel plate and a stainless roller (TOP-15 manufactured by ADAVANTEC) was used. As a result, the production concentration of hydrogen peroxide was 10.3 wt%, the production rate was 0.73 mmol · cm ⁻² · h ⁻¹ , the current efficiency was 37.0%, and the current density was 105.0 mA · cm ⁻² . there were.

[Comparative Example 1]
The reaction was performed in the same manner as in Example 1 except that the open circuit conditions were set (no short circuit between both electrodes). As a result, the reaction did not proceed and the production of hydrogen peroxide was not observed.
[Comparative Example 2]
The reaction was performed in the same manner as in Example 1 except that a mixed gas of hydrogen and oxygen was supplied to the anode chamber. As a result, the reaction proceeded, but hydrogen peroxide was not produced, and the resulting product was only water.
[Comparative Example 3]
The reaction was performed in the same manner as in Example 1 except that a mixed gas of hydrogen and oxygen was supplied to the cathode chamber. As a result, the reaction did not proceed and the production of hydrogen peroxide was not observed.
From the results of Comparative Examples 1 to 3, it is clear that this reaction proceeds by a fuel cell type reaction.

[Comparative Example 4]
The reaction was performed in the same manner as in Example 1 except that the anion exchange membrane was not used. As a result, the production concentration of hydrogen peroxide was 2.2 wt%, the production rate was 0.541 mmol · cm ⁻² · h ⁻¹ , the current efficiency was 38.0%, and the current density was 76.4 mA · cm ⁻² . there were.
[Comparative Example 5]
The reaction was performed in the same manner as in Example 1 except that a cation exchange membrane (Nafion-117 (circular, thickness: 200 μm, diameter: about 25 mm, manufactured by DuPont)) was used as the ion exchange membrane. The production concentration of hydrogen oxide was 5.9 wt%, the production rate was 1.224 mmol · cm ⁻² · h ⁻¹ , the current efficiency was 93.6%, and the current density was 70.2 mA · cm ⁻² .
[Comparative Example 6]
A cation exchange membrane (Nafion-117 (circular, thickness: 200 μm, diameter: about 25 mm, manufactured by DuPont)) is used as the ion exchange membrane, and an alkaline electrolyte solution (2N aqueous sodium hydroxide solution) is continuously added to the anode-side intermediate chamber 2B. The reaction was carried out in the same manner as in Example 1 except that the hydrogen peroxide was not supplied to 1. As a result, the production concentration of hydrogen peroxide was 4.2% by weight, and the production rate was 0.802 mmol · cm ⁻² · h ^−1. The current efficiency was 93.7%, and the current density was 45.9 mA · cm ⁻² .

  The reaction apparatus of the present invention and the method for producing a compound using the apparatus can easily produce hydrogen peroxide from chemicals, particularly hydrogen and oxygen, with high selectivity and high efficiency. Since electric energy can also be obtained, it can be used for producing hydrogen peroxide from a compound useful in the chemical industry, particularly hydrogen and oxygen. Hydrogen peroxide is a useful basic chemical used as a bleach and oxidizer in the chemical, pulp, pharmaceutical, food, textile and semiconductor industries.

It is the schematic of the method of manufacturing hydrogen peroxide from a reducing substance (hydrogen) and an oxidizing substance (oxygen) using the apparatus of this invention. It is a partial exploded perspective view of the apparatus used in Example 1 of the present invention. It is the longitudinal cross-sectional schematic of the apparatus used in Example 1 of this invention.

Explanation of symbols

1 Anode chamber 2A Cathode side intermediate chamber (includes alkaline electrolyte solution)
2B Anode-side intermediate chamber (contains alkaline electrolyte solution)
3 Cathode chamber 4 Anode 5 Cathode 6 Reducing substance (hydrogen) inlet 7 Oxidizing substance (oxygen) inlet 8 Alkaline electrolyte solution inlet 9 Lead wire 10 Ammeter 11 Alkaline electrolyte solution inlet 12 Anion exchange membrane 13 Alkaline electrolyte Solution outlet 14 Reducing substance (hydrogen) outlet 15 Oxidizing substance (oxygen) outlet 21 Gold mesh 22 Teflon (registered trademark) presser plate A
23 Teflon (registered trademark) presser plate B
24 Teflon (registered trademark) spacer 25 Silicon spacer

Claims (8)

  A fuel cell type reaction apparatus for conducting a redox reaction of a system containing a reducing substance and an oxidizing substance, which is divided into an anode chamber, an intermediate chamber, and a cathode chamber by an anode and a cathode, and the intermediate chamber is anion exchange The membrane is partitioned into an anode side intermediate chamber and a cathode side intermediate chamber located between the anode and the anion exchange membrane and between the cathode and the anion exchange membrane, respectively. An alkaline electrolyte solution is introduced, and the anode side intermediate chamber has an electrolyte solution inlet, the anode chamber has a reducing material inlet, and the cathode chamber has an oxidizing material inlet. The fuel cell type reactor is characterized in that the anode and the cathode are connected to each other by an electronic conductor on the outside.   The fuel cell type reactor according to claim 1, wherein the cathode side intermediate chamber has an inlet for an electrolyte solution.   The anode side intermediate chamber has a structure in which an inlet for supplying an alkaline electrolyte solution and a discharge port for the alkaline electrolyte solution are installed, and the alkaline electrolyte solution is continuously supplied to the anode side intermediate chamber. The fuel cell type reactor according to claim 1 or 2, characterized in that   The fuel cell reactor according to any one of claims 1 to 3, wherein the cathode is a catalyst electrode containing a conductive carbon material.   The fuel cell reactor according to claim 4, wherein the conductive carbon material is one or more carbon materials selected from activated carbon, carbon fiber, graphite, carbon whisker, carbon black, and acetylene black.   The fuel cell reactor according to any one of claims 1 to 5, wherein the alkaline electrolyte solution is an aqueous solution containing sodium hydroxide.   A method for producing a compound by an oxidation-reduction reaction, wherein the reducing substance is introduced into the anode chamber using the fuel cell reactor according to any one of claims 1 to 6, and the oxidizing substance is introduced into the cathode chamber. And a compound is obtained from the reducing substance and the oxidizing substance in the cathode side intermediate chamber.   8. The method for producing a compound according to claim 7, wherein the reducing substance is a hydrogen donor, the oxidizing substance is oxygen gas, and the produced compound is hydrogen peroxide.

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