JP5508150B2 - Method for producing hydrogen peroxide - Google Patents

Description

  The present invention relates to a method for producing hydrogen peroxide.

《Technical background》
Hydrogen peroxide (H ₂ O ₂ ) is widely used as an oxidant and, as is well known, used for bleach, disinfectant, disinfectant, preservative, catalyst, explosive, fuel, analytical reagent, etc. Has been.
Compared to heavy metal oxidizers such as nitric acid, chlorine, chromium, etc., there is a growing demand for clean oxidizers that do not derive by-products and waste that have a high environmental impact during the oxidation reaction. Large quantities are being industrially used as fine chemicals, pharmaceuticals, electronic materials, and the like.

<Conventional technology>
As such an industrial method for producing hydrogen peroxide, the so-called organic method and electrolysis method have been known, but at present, the organic method is mainly used.
Currently, a process using anthraquinone has been established as a method for producing hydrogen peroxide by an organic method, that is, a production method by an AO (Auto Oxidation) process method for auto-oxidizing hydroquinones. Therefore, an outline of the process of the anthraquinone method will be described with reference to FIG.
In the anthraquinone method, first, in steps (1), (2), and (3) of FIG. 4, 2-ethylanthraquinone (C ₁₆ H ₁₂ O ₂ ) is mixed and dissolved in an insoluble organic solvent such as benzene. The solution is called a working fluid. Next, in steps (4), (5), and (6), this hydraulic fluid is reduced with hydrogen (H ₂ ) to give 2-ethylanthrahydroquinone (C ₁₆ H ₁₄ O ₂ ) (shown below). (See reaction formula 1).
Then, in steps (7) and (8), the 2-ethylanthrahydroquinone is oxidized with oxygen gas (O ₂ ), that is, air. Then, while returning to the original 2-ethylanthraquinone, hydrogen peroxide (H ₂ O ₂ ) is by-produced (see the following reaction formula 2).
Then, 2-ethylanthraquinone is returned to step (1) and reused, and hydrogen peroxide is extracted and separated from 2-ethylanthraquinone with water in steps (9) and (10). The reaction formula of the anthraquinone method is as shown in the following chemical formula 1 and chemical formula 2.

As such a conventional anthraquinone method, for example, the one shown in the following Patent Document 1 can be mentioned.
JP-A-8-2904

By the way, the following subject was pointed out about the manufacturing method of hydrogen peroxide by such a conventional anthraquinone method.
<First problem>
First, regarding the conventional AO process method, that is, the production method by the anthraquinone method, first, a production process of 2-ethylanthraquinone that performs a catalytic function, an oxidation process of 2-ethylanthrahydroquinone, Problems have been pointed out regarding hydrogen peroxide extraction, separation, and purification processes.
In other words, each of the above steps is complicated, production efficiency (yield) is poor, production time and production equipment costs increase, and a large amount of energy is consumed. Existed.

<< Second problem >>
Secondly, in the production method based on the anthraquinone method, benzene and other organic solvents that are harmful to the human body and the environment are essential.
In addition, hydrogen peroxide is used in large quantities in the manufacturing processes of fine chemicals, pharmaceuticals, electronic materials, etc., but the amount of waste from the manufacturing processes is enormous and the burden on the environment is a problem. It was.
Furthermore, since the production facilities are large, hydrogen peroxide is often not transported at the site of use / demand, but is often transported to the site of use / demand after production. Was pointed out.
In view of these points, problems have been pointed out in terms of safety to the human body and the environment.

<< About the present invention >>
In view of such a situation, the method for producing hydrogen peroxide of the present invention has been made to solve the above-described problems of the prior art.
The first aspect of the present invention is that hydrogen peroxide can be easily and efficiently produced with excellent manufacturing cost, and secondly, it is excellent in terms of safety to the human body and the environment. It aims at proposing the manufacturing method of this.

<About Claim>
The technical means of the present invention for solving such a problem is as follows, as described in the claims.
In this method for producing hydrogen peroxide, triplet state oxygen ( ³ O ₂ ) gas is press-fitted and supplied as a gas-liquid mixed fluid together with water into the microreactor of the microreactor, and the flow path other than the light irradiation surface is formed. The photosensitizer that is attached and coated on the surface is irradiated with light by the light irradiation means.
The gas-liquid mixed fluid of oxygen and water in the triplet state has a dominant viscosity, and flows in a laminar flow so as to slip without turbulent flow entering the microchannel.
Thus, the gas-liquid mixed fluid is brought into contact with the photosensitizer at the interface in a state where the contact area per unit volume is extremely wide, and a conversion process based on molecular diffusion between molecules through the interface, and an intermediate reaction A process and a production reaction process are performed.

First, in the conversion step, excitation energy is generated in the photosensitizer by light absorption based on light irradiation, and the generated excitation energy is transferred to the triplet state oxygen at the interface. Thus, the triplet state oxygen is converted to singlet state oxygen ( ¹ O ₂ ).

Next, in the intermediate reaction step, the oxygen in the singlet state captures protons (H ⁺ ) based on its nucleophilicity to generate hydroperoxide (HO ₂ ).

Therefore, in the production reaction step, the hydroperoxide is added with a counter electron (2e ⁻ ) and a proton (H ⁺ ) based on its electrophilicity to produce hydrogen peroxide (H ₂ O ₂ ).
As described above, by using a microreactor, hydrogen peroxide can be produced at a use site or a demand place.

<About the action>
Since the present invention comprises such means, the following is achieved.
(1) In this production method, first in the conversion step, triplet state oxygen is excited and converted into singlet state oxygen in water using a photosensitizer under light irradiation.
(2) That is, in the microreactor, when the photosensitizer on the flow path forming surface is irradiated with light, oxygen flowing together with water through the micro flow path is singletized.
(3) In this way, the supplied oxygen is singletized.
(4) Singletization is carried out by transferring excitation energy generated by a photosensitizer by light absorption to oxygen in a triplet state.
(5) The singlet-state oxygen thus obtained has nucleophilicity (electron-supplying ability) and strong oxidizing power. In the next intermediate reaction step, protons are captured and hydrolyzed. Peroxide is produced.
(6) The intermediate reaction step is also performed in the micro flow path of the microreactor.
(7) Now, the obtained hydroperoxide exhibits an electrophilicity in which the oxygen end requires a counter electron, and in the next generation reaction step, a counter electron and a proton are added to generate hydrogen peroxide.
(8) The production reaction step is also performed in the microchannel of the microreactor.
(9) The production method of the present invention can produce hydrogen peroxide simply and efficiently as described above.
(10) Moreover, without using an organic solvent, the environmental load due to waste is reduced, and further, it is possible to produce hydrogen peroxide at the site where it is used and where it is demanded.
(11) Therefore, the present invention exhibits the following effects.

<< First effect >>
First, hydrogen peroxide can be produced easily and efficiently with excellent production cost.
That is, in the production method of the present invention, a predetermined microreactor is used and a photosensitizer is used under light irradiation to convert oxygen to singlet, an intermediate reaction step to generate hydroperoxide, Then, hydrogen peroxide is produced by following the production reaction step.
The present invention produces hydrogen peroxide using oxygen and water in a greatly simplified and simplified process and apparatus. Therefore, compared to the above-described conventional anthraquinone method, the production process is not complicated, the production efficiency (yield) is improved, the production time is shortened, the production equipment cost is reduced, and Energy consumption is also reduced.
As a result, hydrogen peroxide can be manufactured and supplied with excellent cost, resulting in significant cost reduction and cost reduction.

<< Second effect >>
Second, it is also excellent in terms of safety to the human body and the environment. That is, the present invention does not use benzene or other organic solvents that are harmful to the human body or the environment in the production of hydrogen peroxide, as in the above-described conventional anthraquinone method.
In addition, hydrogen peroxide is used in large quantities in the manufacturing processes for fine chemicals, pharmaceuticals, electronic materials, etc., and the amount of waste from the manufacturing process is enormous. By adopting the present invention, compared to the anthraquinone method, It is environmentally friendly and the environmental impact of waste is greatly reduced.
Furthermore, the production equipment is not as large as the anthraquinone method, and is easily simplified. This makes it possible to produce hydrogen peroxide at the site of use and where it is demanded, improving safety, and eliminating danger burdens and accident concerns during transportation.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of prior art are solved.

It is a process block diagram for description of the form for inventing about the manufacturing method of the hydrogen peroxide which concerns on this invention. For explanation of the embodiment for carrying out the invention, (1) FIG. 1 is an enlarged sectional explanatory view of the microreactor, and (2) is a plan explanatory view of the microreactor. It uses for description of the form for implementing this invention, (1) FIG. 1 is a disassembled perspective explanatory view of a microreactor. (2) The figure shows a reference example not belonging to the present invention, and is a block diagram of the reactor. It is a process block diagram for description of this kind of conventional example. It is explanatory drawing of a spin quantum state, (1) A figure relates to triplet oxygen, (2) A figure relates to singlet oxygen.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
<< About the manufacturing method of this invention >>
First, the outline of the method for producing hydrogen peroxide according to the present invention is as follows.
This method for producing hydrogen peroxide has the following conversion step, intermediate reaction step, and production reaction step. The transformation process uses the original photosensitizer of the light irradiation, water (H 2 _O) and oxygen ^{(3 O} ₂₎ of the triplet state in the oxygen singlet state excited state ⁽¹ O ₂ ).
In the intermediate reaction step, hydroperoxide (HO ₂ ) is generated from the obtained singlet state oxygen. In the production reaction step, hydrogen peroxide (H ₂ O ₂ ) is produced from the produced hydroperoxide.
The outline of the manufacturing method of the present invention is as described above. Hereinafter, this manufacturing method will be described in detail. First, a detailed description will be given with reference to FIG.

<< triplet state oxygen, singlet state oxygen >>
In the conversion step of the production method of the present invention, triplet state oxygen is excited and converted to singlet state oxygen. Therefore, triplet state oxygen and singlet state oxygen will be described.
First, the electronic ground state of the oxygen molecule O ₂ is a triplet state, and the singlet state of the oxygen molecule O ₂ is a high-energy level electronic excited state.
The oxygen molecule in the singlet state ( ¹ O ₂ ) has nucleophilicity (electron supply property) and is stronger than a normal oxygen molecule, that is, a triplet state oxygen molecule ( ³ O ₂ ). Has oxidizing power. That is, as shown in the explanatory diagram of the spin quantum state in FIG. 5A, the outer electronic structure of the oxygen molecule existing in the normal state of the electron ground state is a triple having two unpaired electron pairs. It is a term state.
On the other hand, as shown in the explanatory diagram of the spin quantum state in FIG. 5 (2), the outer electronic structure of the oxygen molecule in the singlet state of the electron excited state has a counter electron and is nucleophilic ( Compared with triplet oxygen molecules in the electron ground state, the energy held by the outer electrons is larger. A singlet state oxygen molecule has a very large energy, is highly reactive, and has a strong oxidizing power as compared with a normal triplet state oxygen molecule. In FIG. 5, illustration of the K shell (s orbit) of the electron shell is omitted.
The triplet state oxygen and singlet state oxygen are as described above.

<Conversion process>
Next, the outline | summary is demonstrated about the conversion process of the manufacturing method of this invention. In the conversion step, as shown in steps (1), (2), (3), and (4) of FIG. 1, the photosensitizer P is used under light irradiation to form a triplet state in water. Oxygen is excited and converted to singlet oxygen.
Photosensitizers P that function as catalysts in photochemical reactions include rose bengal, methylene blue, other organic dye compounds, polysilicon (porous silicon), other inorganic materials, etc., which are brought into an excited state based on light irradiation. A wide range of substances that can contribute to the intersystem crossing. This includes a so-called photocatalyst such as titanium dioxide (titania) and other metal oxides.
In the conversion step, excitation energy is generated in the photosensitizer P by light absorption, and the excitation energy thus generated is transferred to triplet state oxygen, so that triplet state oxygen is converted into singlet. Excited and converted to oxygen in the state.
That is, in the conversion step, the photosensitizer P is irradiated with light so that the photosensitizer P absorbs the photon hν (light energy), and then the photosensitizer P is brought into an excited state. → And, when the photosensitizer P returns to the ground state, the released photon (light energy) is absorbed in the triplet state oxygen, so that the intersystem crossing occurs, and the excited singlet state oxygen Is obtained.
In this way, it is possible to excite triplet state oxygen to form singlet state, that is, to excite outer electrons involved in chemical reaction, and to change the level of energy state depending on the total spin quantum number , The energy difference is excessive and usually hardly occurs. In other words, it is forbidden to spin. On the other hand, by using the photosensitizer P as described above, the forbidden state is broken and inter-term crossing is performed.
The outline of the conversion process is as described above.

<< Reactions in the conversion process >>
Next, a chemical reaction in such a conversion step will be specifically described based on a reaction formula or the like. First, the photosensitizer P under light irradiation is as follows.
By irradiation with light (photon hν), outer electrons (e ⁻ ) in the outer orbit (steady orbit) on the surface of the photosensitizer P are excited and moved from the outer orbit to the excitation orbit. Accordingly, holes (hole ⁺ ), which are electron vacancies that are lost due to electrons being escaped, are formed in the outer shell orbit of the surface of the photosensitizer P.
The formed holes have a property of extracting electrons from other substances to fill the electron vacancies, that is, an oxidizing power. Therefore, according to the reaction formula of the following chemical formula 3, electrons are extracted from water molecules (H ₂ O) and oxidized, and radically split to generate protons (H ⁺ ) and OH radicals (.OH).

The OH radical, that is, the hydroxy radical generated in this way has a strong oxidizing power (electron scavenging power) as is well known. Therefore, water molecules are oxidatively decomposed according to the reaction formula shown below. In other words, OH radicals take hydrogen atoms from water, return to water themselves, and generate and separate oxygen molecules (O ₂ ) as oxides, while generating hydrogen (H ⁺ + e ⁻ ) (also called hydrogen radicals). Is generated).
Here, when the reaction formulas of Chemical Formula 3 and Chemical Formula 4 are synthesized together, the following Reaction Formula 5 is obtained. The reaction formula of Chemical Formula 5 is widely known as a photooxidation formula (photochemical decomposition reaction formula) of water molecules.

With respect to the photosensitizer P under light irradiation, the above-described crossing of oxygen O ₂ is performed together with the above-described proton and electron generation reaction. That is, the triplet state oxygen ( ³ O ₂ ) is excited to the excited singlet state oxygen ( ¹ O ₂ ) based on the excitation of the photosensitizer P by the reaction formula of the following chemical formula 6. Transition and transformation.
In addition, the following chemical formula 7 is an electron schematic diagram in which the outermost electrons are represented by dots in the chemical formula of chemical formula 6 (the same applies to the chemical formulas of chemical formulas 9 and 11 below).

変換工程における反応等については、以上のとおり。

The reaction in the conversion process is as described above.

<< Intermediate reaction process, production reaction process >>
Next, regarding the production method of the present invention, the intermediate reaction step and the production reaction step subsequent to the conversion step described above will be described.
First, as described above, singlet oxygen obtained in the conversion step has nucleophilicity (electron supply property) and strong oxidizing power. Therefore, in the intermediate reaction step, singlet oxygen is used as a nucleophile (supplement to supply electrons) as shown in steps (4), (5), (6) of FIG. Agent) to follow the oxidation process of capturing protons, thereby producing hydroperoxide (HO ₂ ). For the proton (H ⁺ ), see the reaction formulas of Chemical Formula 3, Chemical Formula 4, and Chemical Formula 5.

The hydroperoxide obtained in the above-described intermediate reaction step exhibits electrophilicity for obtaining a counter electron at the oxygen end. Accordingly, hydroperoxide follows a reduction process in which counter electrons (2e ⁻ ) and protons (H ⁺ ) are added, as shown in the following reaction formulas 10 and 11, in the next production reaction step. Hydrogen (H ₂ O ₂ ) is produced. For the counter-electron and proton, see the reaction formulas of Chemical Formula 4 and Chemical Formula 5.

中間反応工程，生成反応工程については、以上のとおり。

The intermediate reaction process and the production reaction process are as described above.

<< About the manufacturing apparatus 1 >>
Next, the manufacturing apparatus 1 will be described. That is, the hydrogen peroxide manufacturing apparatus 1 that performs the above-described hydrogen peroxide manufacturing method, its conversion process, intermediate reaction process, and generation reaction process will be described.
As the manufacturing apparatus 1, the microreactor 2 shown in FIG. 2 or FIG. 3 (1) is used.

<< Production apparatus 1 using microreactor 2 >>
The manufacturing apparatus 1 using the microreactor 2 will be described with reference to FIG. 2 (1), FIG. 2 (2), FIG. 2 (1), and the like.
In this manufacturing apparatus 1, triplet state oxygen is supplied to the micro flow path 4 of the micro reactor 2 together with water, and the photosensitizer P coated on the flow path forming surface 5 is irradiated with light. The above-described conversion process, intermediate reaction process, and production reaction process of the manufacturing process are performed.
That is, triplet state oxygen ( ³ O ₂ ) supplied to the microchannel 4 together with water based on the light irradiation to the photosensitizer P attached and coated on the channel formation surface 5 of the microreactor 2, Hydrogen peroxide (H ₂ O ₂ ) is generated based on the conversion to singlet state oxygen ( ¹ O ₂ ) and thus the generation of hydroperoxide (HO ₂ ) from singlet state oxygen.
The outline of the manufacturing apparatus 1 using the microreactor 2 is as described above.

<< Microreactor 2 >>
These will be further described in detail. First, the microreactor 2 will be described.
The microreactor 2 includes a reactor having a micro flow path 4 having a micro-order fine structure. The micro flow path 4 has a flow path width of about several tens of μm to several 1,000 μm, for example, 100 μm to 500 μm. The path depth is about several μm to several 100 μm, for example, 25 μm to 100 μm.
The illustrated microreactor 2 is made of, for example, a three-ply glass plate having a thickness of about 2 mm, and sandwich plates in which holder plates 7 and 8 are closely stacked and fixed so as to sandwich the main body plate 6 from above and below. Consists of structure.
The microplate 4 is formed in the main body plate 6, and the upper holder plate 7 is transparent and light-transmitting in relation to light irradiation in the illustrated example, whereas the lower holder plate 7 8 may not be transparent.
The micro flow path 4 has a channel shape. In the illustrated example, the micro flow path 4 is linearly formed in the longitudinal direction of the main body plate 6 and reciprocated repeatedly in the short direction, and is continuously engraved in a zigzag meandering manner. Each bent portion is curved in a curved shape.

A gas-liquid mixed fluid F of triplet-state oxygen gas and water is supplied from the supply unit 9 to the pump 10 (typically a syringe pump) or a fine tube ( It is press-fitted and supplied through a microtube 11. As the oxygen gas, pure oxygen is used, but a gas containing oxygen can also be used.
The micro flow path 4 formed in the main body plate 6 is formed in a semicircular cross section or a rectangular cross section on a flow path forming surface 5 having an upper surface, both side surfaces, a bottom surface, and the like. In the illustrated example, the upper surface of the flow path forming surface 5 is a light irradiating surface 12 for transmitting light. The light irradiating surface 12 is opened and hermetically sealed with a higher holder plate 7.
Except for such a light irradiation surface 12, the microchannel 4 formed on the main body plate 6 has the photosensitizer P attached and coated on the channel forming surfaces 5 on both side surfaces and the bottom surface thereof. For example, an inorganic photosensitizer P such as polysilicon is fixed and supported in the form of a film by baking, sintering, coating, or the like.
Further, the light irradiation means 13 is disposed to face the micro flow path 4. The light irradiation means 13 is disposed so as to face the microchannel 4 via the upper holder plate 7 and the light irradiation surface 12.
As the light irradiation means 13 which is a light source, for example, a mercury lamp, black light, LED, and further sunlight such as natural energy can be used. Then, light (photon quantum hν) having a wavelength sufficient to photoexcite (photochemical reaction) the photosensitizer P to be used is irradiated. For example, ultraviolet light having a wavelength of about 200 nm to 300 nm or visible light having a wavelength of about 400 nm to 700 nm is irradiated.
The microreactor 2 is as described above.

<< Reactions in the microreactor 2 >>
Next, the reaction in the microreactor 2 will be described. The gas-liquid mixed fluid F press-fitted and supplied to the microchannel 4 of the microreactor 2, that is, triplet state oxygen (mostly dissolved in water to become dissolved oxygen) and water are supplied from the inlet of the microchannel 4. It flows as a laminar flow toward the exit.
Regarding laminar flow, it is as follows. The microchannel 4 has a very small and narrow channel width, and the gas-liquid mixed fluid F is press-fitted and supplied, so the Reynolds number (the dimensionless number that is the ratio of the inertial force to the frictional force due to viscosity) is small. A laminar flow is formed. The gas-liquid mixed fluid F has a dominant viscosity, and does not enter into a turbulent flow but becomes a laminar flow that slides.
Therefore, the gas-liquid mixed fluid F of oxygen and water in the triplet state becomes a laminar flow while contacting the photosensitizer P at the interface 14 in a state where the contact area (specific surface area) per unit volume is extremely wide. And flow.
The photosensitizer P generates excitation energy by light absorption based on light irradiation from the light irradiation means 13. Therefore, at the interface 14 between the photosensitizer P for which excitation energy is generated and the gas-liquid mixed fluid F flowing in a laminar flow, that is, at the interface 14 between the photosensitizer P and triplet state oxygen, excitation is performed. Energy is transferred from the photosensitizer P side to the triplet state oxygen side based on molecular diffusion.
Therefore, in the microchannel 4, the excitation energy is transferred in this manner, whereby triplet state oxygen is converted to singlet state oxygen. Then, in the micro flow path 4, such conversion into singlet oxygen, generation of hydroperoxide, and generation of hydrogen peroxide are performed.

Such a reaction is performed based on molecular diffusion. Each reaction is performed by molecular diffusion at the interface 14 between the gas-liquid mixed fluid F and the photosensitizer P flowing in a laminar flow through the microchannel 4. The molecular diffusion is as follows.
At the interface 14, there is almost no mass transfer in the flow path width direction due to hydrodynamic force like turbulent flow, and there is no energy loss for that purpose. Mass transfer in the channel width direction is mainly due to molecular diffusion, and mass transfer by hydrodynamic force works almost only in the flow direction. Accordingly, the above-described reaction process is performed based on molecular diffusion between substances and under a large contact area as described above.
As described above, by adopting the microreactor 2, the conversion process, the intermediate reaction process, and the production reaction process are performed efficiently, quickly and reliably by the molecular diffusion at the interface 14 having a large contact area in a laminar flow. The The obtained hydrogen peroxide is separated, extracted, and recovered, for example, by distillation or the like, through the fine tube 11 to the recovery unit 15.
The reaction in the microreactor 2 is as described above. The manufacturing apparatus 1 using the microreactor 2 is as described above.

《Reference example》
Here, reference examples not belonging to the present invention will be described. That is, the hydrogen peroxide production apparatus 1 using the reactor 3 shown in FIG.
In the reactor 3 of the production apparatus 1, the photosensitizer P is dispersed in the water of the container, and oxygen gas, that is, triplet state oxygen ( ³ O ₂ ) is supplied, most of which is dissolved in water. It becomes dissolved oxygen. Typically, triplet state oxygen is supplied from the supply unit 17 into the water dispersed in advance by supplying the photosensitizer P from the supply unit 16 in advance.
Then, the photosensitizer P is irradiated with light, so that triplet state oxygen is excited and converted into singlet state oxygen ( ¹ O ₂ ), and from the singlet state oxygen to hydroperoxide (HO _2). ) Is generated, hydrogen peroxide (H ₂ O ₂ ) is generated. The conversion step, intermediate reaction step, and production reaction step described above are performed by light irradiation. The illustration of the water supply unit is omitted.

In the production apparatus 1 using the reactor 3, unlike the production apparatus 1 using the microreactor 2 described above, the powder photosensitizer P is dispersed in water. That is, for example, the photosensitizer P such as rose bengal or titanium blue is dispersed and distributed in water as fine particles, and is almost uniformly diffused.
Therefore, based on the light irradiation to the photosensitizer P by the light irradiation means 13, as described above, the excitation energy is generated and transferred to convert oxygen into a singlet state, and hydroperoxide and hydrogen peroxide are converted. After being generated, it is separated, extracted and recovered by the recovery unit 15 by, for example, distillation.
As described above, this manufacturing apparatus 1 manufactures hydrogen peroxide based on the so-called batch-type water replacement method. However, the manufacturing apparatus 1 using the microreactor 2 described above, that is, a wide contact area and molecular diffusion at the interface 14, In comparison, the efficiency is inferior, but the cost is better.
The temporal order of dispersion of the photosensitizer P in water and the supply of oxygen in the triplet state is typically the former as described above, but should be simultaneous or the latter first. Is also possible.
For reference examples, see above.

《Action etc.》
The method for producing hydrogen peroxide according to the present invention is configured as described above. Therefore, it becomes as follows.
(1) In the production method of the present invention, first, in the conversion step, by using the photosensitizer P under light irradiation, normal triplet state oxygen ( ³ O ₂ ) is excited in water. It is converted into excited singlet oxygen ( ¹ O ₂ ) (the reaction formulas of Chemical Formulas 6 and 7 above, Steps (1), (2), (3), (4), etc. of FIG. See).

(2) That is, the photosensitizer P adhered to the flow path forming surface 5 of the microreactor 2 is irradiated with light by the light irradiation means 13.
Therefore, at the interface 14 with the photosensitizer P, the triplet state oxygen of the gas-liquid mixed fluid F flowing in a laminar flow with the water in the microchannel 4 is converted into a singlet state oxygen based on molecular diffusion. Excited and converted (see FIG. 2, (1), (2), FIG. 3, (1), etc.)).

  (3) In this way, triplet state oxygen supplied into water is excited and converted to singlet state oxygen.

(4) Such a conversion process is performed in the manufacturing apparatus 1 using the microreactor 2 as follows.
That is, excitation energy is generated in the photosensitizer P by light absorption, and the generated excitation energy is transferred to triplet state oxygen, so that triplet state oxygen is converted into a singlet state. Excited and converted to oxygen.

(5) In this production method, oxygen in the singlet state is thus obtained in the conversion step, and hydroperoxide (HO ₂ ) is produced from the singlet state oxygen in the next intermediate reaction step.
That is, singlet-state oxygen has nucleophilicity (electron supply property) and has a stronger oxidizing power than ordinary triplet-state oxygen. Thus, protons (H ⁺ ) are captured and hydroperoxide is generated (the reaction formulas of the above-mentioned chemical formulas 8 and 9, and further, the chemical reaction formulas of the above-mentioned chemical formulas 3, 4, and 5 and steps (4) and ( (See 5), (6), etc.)

  (6) Such an oxidation process of the intermediate reaction step is performed in the gas-liquid mixed fluid F of the microchannel 4 or in the water of the reactor 3 in the manufacturing apparatus 1 using the microreactor 2 (FIG. 2). , See FIG.

(7) In this production method, when hydroperoxide is obtained in the intermediate reaction step, hydrogen peroxide is produced from hydroperoxide (HO ₂ ) in the next production reaction step.
That is, hydroperoxide exhibits electrophilicity for the counter electron at its oxygen end, and hydrogen peroxide is generated by adding a counter electron (2e ⁻ ) and a proton (H ⁺ ) (the above formula 10, 11 reaction formula, further, the reaction formulas of the above chemical formulas 3, 4 and 5 and steps (6), (7) and (8) in FIG. 1).

  (8) Such a production reaction step is performed in the gas-liquid mixed fluid F in the microchannel 4 in the manufacturing apparatus 1 using the microreactor 2 (see FIGS. 2 and 3).

(9) As described above, the production method of the present invention pays attention to the nucleophilicity (electron supply property) and oxidizing power of singlet oxygen, and adopts a predetermined microreactor 2 together with the photosensitizer P. As a result, hydrogen peroxide can be easily and easily produced from oxygen (air) and water.
Hydrogen peroxide is produced by adding hydrogen atoms to both ends of oxygen in a singlet state by an easy production method without complicating the process with a simple structure.

(10) In addition, no organic solvent is used in the production method of the present invention. In addition, the environmental load caused by the waste generated during the production is greatly reduced. Furthermore, the production apparatus 1 that is simplified and simplified enables production of hydrogen peroxide at the use site / demand place.
The operation of the present invention is as described above.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 2 Microreactor 3 Reactor 4 Micro flow path 5 Flow path formation surface 6 Main body plate 7 Holder plate 8 Holder plate 9 Supply part 10 Pump 11 Fine tube 12 Light irradiation surface 13 Light irradiation means 14 Interface 15 Recovery part 16 Supply Part 17 Supply part F Gas-liquid mixed fluid P Photosensitizer

Claims (1)

Photosensitization in which triplet state oxygen ( ³ O ₂ ) gas is press-fitted and supplied as a gas-liquid mixed fluid together with water into the microreactor of the microreactor, and is coated on the flow path formation surface other than the light irradiation surface. The agent is irradiated with light by the light irradiation means,
The gas-liquid mixed fluid of oxygen and water in the triplet state is dominant in viscosity, and flows in a laminar flow so as to slip without turbulent flow entering the microchannel,
Thus, the gas-liquid mixed fluid is brought into contact with the photosensitizer at the interface in a state where the contact area per unit volume is extremely wide, and a conversion process based on molecular diffusion between molecules through the interface, and an intermediate reaction Process and production reaction process,
First, in the conversion step, excitation energy is generated in the photosensitizer by light absorption based on light irradiation, and the generated excitation energy is transferred to oxygen in the triplet state at the interface, thereby the triplet. State oxygen is converted to singlet state oxygen ( ¹ O ₂ ),
Next, in the intermediate reaction step, the oxygen in the singlet state captures a proton (H ⁺ ) based on its nucleophilicity to produce hydroperoxide (HO ₂ ),
Therefore, in the production reaction step, the hydroperoxide is added with a counter electron (2e ⁻ ) and a proton (H ⁺ ) based on its electrophilicity to produce hydrogen peroxide (H ₂ O ₂ ),
Thus, the manufacturing method of hydrogen peroxide characterized by exhibiting the function which can manufacture hydrogen peroxide in a use field and a demand place by utilizing a microreactor.

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