JP7787754B2 - Solid electrolyte electrolytic device and method for producing polycarbonate and polyurethane using the same - Google Patents

Description

This disclosure relates to a solid electrolyte electrolysis device and a method for producing polycarbonate and polyurethane using the same.

Carbon dioxide (hereafter sometimes abbreviated as _CO2 ) is emitted when energy is extracted from fossil fuels and other sources. Rising carbon dioxide concentrations in the atmosphere are said to be one of the causes of global warming, but because carbon dioxide is an extremely stable substance, it is difficult to decompose and reuse. Therefore, there is a need for technology that can convert carbon dioxide into other substances and reuse them as resources.

In recent years, research into carbon dioxide reduction using electrical energy has been widely conducted. In solid electrolyte electrolysis devices that reduce carbon dioxide, carbon dioxide is generally dissolved in an aqueous solution containing an electrolyte supplied to the cathode (hereinafter sometimes referred to as the cathode), and an aqueous solution containing water and an electrolyte is supplied to the anode (hereinafter sometimes referred to as the anode) for electrolysis. An electrolyte for exchanging ions is provided between the cathode and anode, and an ion exchange membrane is sometimes used as a material for this. An example of such a solid electrolyte electrolysis device is the carbon dioxide electrolysis device disclosed in Patent Document 1.

Japanese Patent Application Laid-Open No. 2018-154901

In the carbon dioxide electrolysis device disclosed in Patent Document 1, water is supplied as the anode electrolyte and electrolyzed to generate hydroxide ions, but the applied voltage required for this electrolysis is high, which could increase the amount of energy required for electrolysis.

In addition, polycarbonate production typically involves the cumene process, which produces phenol from benzene and propylene. The cumene process requires a reaction temperature of 200°C, which requires equipment capable of handling high temperatures, resulting in high capital investment costs. It is also undesirable because it generates large amounts of carbon dioxide. Carbon monoxide is generally obtained by adding a small amount of oxygen to coal and baking it, but this requires large-scale equipment and safety facilities, which can result in high capital investment costs.

Polyurethane manufacturing methods generally involve oxidizing ethylene to produce ethylene oxide. This method requires ethylene to be oxidized at 240°C, which requires equipment capable of handling high temperatures and increases capital investment costs. It is also undesirable because it generates large amounts of carbon dioxide. Furthermore, carbon monoxide is generally obtained by adding a small amount of oxygen to coal and baking it, but this requires large-scale equipment and safety facilities, which can increase capital investment costs.

Therefore, an object of the present disclosure is to provide a technology related to a solid electrolyte electrolysis device that can reduce the energy required for electrolysis by reducing the applied voltage required for electrolysis at the anode. Another object is to provide a method for producing polycarbonate using a solid electrolyte electrolysis device of the present disclosure to simultaneously produce phenol and carbon monoxide from _CO2 and benzene through organic electrolysis, thereby enabling _CO2 reuse and equipment efficiency (simplification), and reducing production costs and capital investment costs. Another object is to provide a method for producing polyurethane using a solid electrolyte electrolysis device of the present disclosure to simultaneously produce olefin oxide and carbon monoxide from _CO2 and olefin through organic electrolysis, thereby enabling _CO2 reuse and equipment efficiency (simplification), and reducing production costs and capital investment costs.

As a result of extensive research into achieving the above-mentioned objective, the inventors discovered that by including benzene or an olefin as the treated substance subjected to electrolysis at the anode, the applied voltage required to electrolyze these treated substances can be reduced compared to the case of using water, leading to the completion of the disclosed technology.

Furthermore, when the treated body contains benzene, phenol is obtained by electrolysis at the anode, and carbon monoxide (hereinafter sometimes abbreviated as CO) is obtained by electrolysis at the cathode. The phenol and carbon monoxide obtained in this manner can be used as raw materials for producing polycarbonate. Furthermore, when the treated body contains an olefin, olefin oxide is obtained by electrolysis at the anode, and carbon monoxide is obtained by electrolysis at the cathode. These olefin oxides and carbon monoxide can be used as raw materials for producing polyurethane. In this way, it has been found that including benzene or an olefin as the treated body used in the anode makes it possible to create a seamless process leading to the production of recycled carbon dioxide products. In other words, it has been found that a more efficient (and therefore more simplified) production process can be configured than conventional polycarbonate and polyurethane production processes, enabling reduced capital investment costs.

Furthermore, by using saltwater as the treatment body in the solid electrolyte electrolysis device, it is possible to produce chlorine through electrolysis at the anode and carbon monoxide through electrolysis at the cathode. These chlorine and carbon monoxide can also be used as raw materials for producing phosgene, an intermediate product in the polycarbonate and polyurethane production process. This further promotes the reuse of carbon dioxide and makes the chlorine production process more efficient (simplified), further reducing capital investment costs. In other words, the disclosed technology is as follows:

According to one aspect of the present disclosure,
a cathode where a reduction reaction takes place;
an anode that forms a pair of electrodes with the cathode;
an electrolytic cell for holding a treatment body to be electrolyzed by the anode;
a solid electrolyte interposed between the cathode and the anode in contact therewith;
a voltage application unit that applies a voltage between the cathode and the anode,
It is possible to provide a solid electrolyte electrolysis device, characterized in that the treated body contains benzene or an olefin.

This disclosure makes it possible to provide technology related to solid electrolyte electrolysis devices that reduce the energy required for electrolysis by reducing the applied voltage required for electrolysis at the anode.

FIG. 1 is a schematic diagram illustrating an example of a solid electrolyte electrolysis device according to the present disclosure. FIG. 1 is a conceptual diagram illustrating how CO ₂ can be locally and efficiently adsorbed by adding a solid base to the cathode surface in a solid electrolyte electrolysis device preferably used in an embodiment of the present disclosure. FIG. 1 is an explanatory diagram showing a method for producing polycarbonate in the present disclosure. FIG. 1 is a flow diagram showing an example of equipment using the polycarbonate production method according to the present disclosure. FIG. 1 is an explanatory diagram showing a method for producing polyurethane in the present disclosure. FIG. 1 is a flow diagram showing an example of equipment used in the production of polyurethane according to the present disclosure. FIG. 10 is an enlarged view of a portion of a cyclic voltammogram in Example 4. FIG. 1 shows the results of FID-GC analysis of the treated body (Example 4), a standard aqueous solution of phenol, and ion-exchanged water before and after the oxidation reaction (electrolysis) at the anode.

The solid electrolyte electrolysis device and the method for producing polycarbonate and polyurethane using the same according to the present disclosure are described in detail below. However, the present disclosure is not limited to the embodiments described below. Furthermore, in this disclosure, the term "to" used when describing numerical values indicates a value greater than or equal to the lower limit and less than or equal to the upper limit.

≪Solid electrolyte electrolysis device 100≫
First, a solid electrolyte electrolysis device (also referred to as an electrolytic cell or an electrolytic module) according to this embodiment will be described with reference to Figure 1. As shown in Figure 1, the solid electrolyte electrolysis device 100 according to this embodiment includes a cathode (negative electrode) 101, an anode (positive electrode) 102 that forms a pair of electrodes with the cathode 101, a solid electrolyte 103 that is disposed between the cathode 101 and the anode 102 in a contact state with at least a portion of the cathode 101 and the anode 102, a current collector 104 that is in contact with the cathode 101 at a surface 101-2 opposite to a contact surface 101-1 with the solid electrolyte 103, a support plate 105 that is in contact with the anode 102 at a surface 102-1 opposite to a contact surface 102-2 with the solid electrolyte 103, and a voltage application unit 106 that applies a voltage between the current collector 104 and the support plate 105 (i.e., between the cathode and the anode). Furthermore, an electrolytic cell 108 (hereinafter sometimes abbreviated as electrolytic cell 108) for storing the treated product of electrolysis at the anode is provided on the surface of the support plate 105 opposite the anode 102. _CO2 in a gas phase state is supplied by a supply source and a supply device (not shown). For the sake of explanation, the solid electrolyte electrolysis device 100 shown in FIG. 1 is illustrated with the cathode 101, anode 102, and other components separated. In reality, however, the current collector plate 104, cathode 101, solid electrolyte 103, anode 102, and support plate 105 are each bonded by a predetermined method and integrated into one unit. Each component may be configured to be detachable to constitute a single solid electrolyte electrolysis device 100. Each component will be described in detail below.

<Cathode 101>
(Reduction reaction at cathode 101)
The reduction reaction at the cathode 101 varies depending on the type of solid electrolyte 103 used in the solid electrolyte electrolysis device 100. When a cation exchange membrane is used as the solid electrolyte 103, the reduction reactions of the following formulas (1) and (2) occur, and when an anion exchange membrane is used as the solid electrolyte, the reduction reactions of the following formulas (3) and (4) occur.

(Basic structure and materials of cathode 101)
The cathode 101 is a gas diffusion electrode including a gas diffusion layer. The gas diffusion layer includes a porous material such as paper, nonwoven fabric, or mesh made of carbon or metal. Examples of electrode materials for the cathode 101 include graphite carbon, glassy carbon, titanium, and stainless steel. The cathode catalyst included in the cathode 101, capable of reducing CO ₂ (carbon dioxide) to CO (carbon monoxide), includes a metal selected from silver, gold, copper, or a combination thereof. More specifically, the catalyst includes gold, gold alloy, silver, silver alloy, copper, copper alloy, or a mixed metal containing at least one of these. The type of catalyst is not particularly limited as long as it functions as a catalyst, and can be determined taking into account corrosion resistance and other factors. For example, the catalyst may not include amphoteric metals such as Al, Sn, or Zn, thereby improving corrosion resistance. The catalyst can be supported on the cathode 101 (or electrode material) by carrying out a known method such as vapor deposition, deposition, adsorption, accumulation, adhesion, welding, physical mixing, or spraying.

(Solid Base 107)
Here, as shown in FIG. 2, the cathode 101 has a solid base 107 . The solid base 107 is not particularly limited as long as it is a base that is solid at room temperature (25° C.), and examples thereof include potassium bicarbonate (KHCO ₃ ), sodium hydroxide (NaOH), an oxide of an alkaline earth metal, a hydroxide of an alkaline earth metal, or a carbonate of an alkaline earth metal {e.g., magnesium oxide (MgO), magnesium hydroxide (Mg(OH) ₂ ), magnesium carbonate (MgCO ₃ ), calcium oxide (CaO), calcium hydroxide (Ca(OH) ₂ ), calcium carbonate (CaCO ₃ ), strontium oxide (SrO), strontium hydroxide (Sr(OH) ₂ ), strontium carbonate (SrCO ₃ ), barium oxide (BaO), barium hydroxide (Ba(OH) ₂ ), barium carbonate (BaCO ₃ ), etc.}, an oxide of a rare earth metal, a hydroxide of a rare earth metal, or a carbonate of a rare earth metal {e.g., yttrium oxide (Y ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), etc.}, hydrotalcite (e.g., metal complex hydroxide, carbonate, LDH, HT-CO ₃ , HT-OH, etc.), surface-base-treated zeolite, base-treated molecular sieve, surface-base-treated porous alumina (KF-Al ₂ O ₃ ), etc. are preferably used. In particular, weakly basic solid bases with small atomic numbers are more preferred. Furthermore, water-insoluble solid bases such as alkaline earth metal oxides, alkaline earth metal hydroxides or alkaline earth metal carbonates, rare earth metal oxides, rare earth metal hydroxides or rare earth metal carbonates are more preferred because they are not washed away by water in the gas or water generated by the reaction, and therefore do not reduce the durability of the cathode having the solid base 107. Here, "water-insoluble" means that 10 mg of the base does not dissolve in 100 mL of water at 20°C. The solid base 107 is preferably present on the contact surface 101-1 of the cathode 101 with the solid electrolyte 103. The reason for this configuration is that the interface between the cathode 101 and the solid electrolyte 103 is a reaction site. The solid base 107 may be present as a mixture with the material of the cathode 101, or may be present in an integrated state as a compound. The solid base 107 can be supported on the cathode 101 (or electrode material) by carrying out a known method such as coating, vapor deposition, precipitation, or physical mixing. The mass of the solid base per unit area is not particularly limited, but is, for example, 0.1 to 10 mg/cm ² , preferably 0.1 to 6 mg/cm ² .

Here, the following mechanism of action is presumed to explain why the use of the solid base 107 improves efficiency. First, when low-concentration _CO2 gas, such as factory exhaust gas, containing 10 to 20% CO2, is supplied to the solid electrolyte electrolysis device 100, the _CO2 is difficult to adsorb on the surface of the cathode 101 due to its low concentration. Therefore, as shown in FIG. 1, by adding the solid base 107 to the surface of the cathode 101, _CO2 can be efficiently adsorbed locally at the location where the solid base is present, and _CO2 reduction can proceed. Furthermore, when a cation exchange membrane is used as the solid electrolyte 103, it is understood that if there is a large amount of H ⁺ on the surface of the cathode 101, _CO2 cannot be sufficiently adsorbed. In this case, the presence of the solid base 107 is thought to promote the reaction (for example, when an ion exchange membrane is used, it is preferable to control the pH so that pH > 2). On the other hand, when an anion exchange membrane is used as the solid electrolyte, ^OH- is present on the cathode surface, which allows _CO2 to be adsorbed, making it suitable for _CO2 reduction. However, it is understood that if there is too much OH ^−, it will be adsorbed as stable CO ₃ ²⁻ , and the CO ₂ reduction reaction will not proceed sufficiently. In this case, it is thought that the presence of a weakly basic solid base 107 will allow the CO ₂ reduction reaction to proceed more efficiently (for example, when an ion exchange membrane is used, it is preferable to control the pH so that the pH is less than 12). In the present disclosure, an electrode having such a solid base and catalyst can be expressed as "an electrode having a catalyst, an electrode material having the catalyst, and at least a solid base provided on the electrode material" (in other words, an electrode having an electrode material having a catalyst and a solid base), or "a cathode having a catalyst and further having a solid base," etc.

<Anode 102>
(Oxidation Reaction at the Anode 102)
The oxidation reaction at the anode 102 varies depending on the type of solid electrolyte 103 used in the solid electrolyte electrolysis device 100. When a cation exchange membrane is used as the solid electrolyte 103, the oxidation reaction of the following formula (5) occurs, and when an anion exchange membrane is used as the solid electrolyte 103, the oxidation reaction of the following formula (6) occurs.

Furthermore, when the treated substance, as described below, is benzene, the oxidation reaction shown in Figure 3 occurs, producing phenol. In other words, organic electrolysis is possible, in which electrolysis and organic synthesis occur simultaneously. Similarly, when an olefin is used as the treated substance, the oxidation reaction shown in Figure 5 occurs, producing olefin oxide.

(Basic structure and material of the anode 102)
The anode 102 is a gas diffusion electrode including a gas diffusion layer. The gas diffusion layer includes a conductive and porous material such as carbon paper, nonwoven fabric, or metal mesh. Examples of electrode materials for the cathode 101 include graphite carbon, glassy carbon, titanium, and SUS. Examples of electrode materials for the anode 102 include _V2O5 , _MnOx , _MoO3 , _WO3 , _ZrO2 , _Cr2O3 , _Ir , _IrO2 , Ru, _RuO2 , Rh, _RhOx , Co, CoOx, Cu, CuOx, Fe, _FeOx , FeOOH, FeMn, Ni, NiOx, NiOOH, NiCo, NiCe, NiC, NiFe, NiCeCoCe, NiLa, NiMoFe, NiSn, NiZn, SUS, Au, and Pt.

<Solid electrolyte 103>
The solid electrolyte 103 is interposed between the cathode 101 and the anode 102 in a state of at least partial contact with each of the cathode 101 and the anode 102. Here, the solid electrolyte 103 is not particularly limited to a polymer membrane, but is preferably a cation exchange membrane or an anion exchange membrane, and more preferably an anion exchange membrane. Examples of the cation exchange membrane include strongly acidic cation exchange membranes in which sulfonic groups are introduced into a fluororesin matrix, such as Nafion (registered trademark) 117, Nafion 115, Nafion 212, and Nafion 350 (manufactured by DuPont), and strongly acidic cation exchange membranes in which sulfonic groups are introduced into a styrene-divinylbenzene copolymer matrix, such as NeoSepta CMX (manufactured by Tokuyama Soda Co., Ltd.). Examples of the anion exchange membrane include anion exchange membranes containing quaternary ammonium groups, primary amino groups, secondary amino groups, tertiary amino groups, and mixtures of these ion exchange groups. Specific examples include Neocepta (registered trademark) ASE, AHA, AMX, ACS, AFN, AFX (manufactured by Tokuyama Corporation), Selemion (registered trademark) AMV, AMT, DSV, AAV, ASV, AHO, AHT, APS4 (manufactured by Asahi Glass Co., Ltd.), etc.

<Current Collector Plate 104>
Examples of the current collector plate 104 include metal materials such as copper (Cu), nickel (Ni), stainless steel (SUS), nickel-plated steel, and brass, and among these, copper is preferred from the viewpoints of ease of processing and cost. When the negative electrode current collector plate 104 is made of a metal material, examples of the shape of the negative electrode current collector plate include metal foil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal.

As shown in FIG. 1, the current collector plate 104 is provided with a gas supply hole 104-1 and a gas recovery hole 104-2 for supplying and recovering gas (raw material gas and generated gas) to the cathode 101. The gas supply hole 104-1 and the gas recovery hole 104-2 make it possible to uniformly and efficiently deliver raw material gas to the cathode 101 and discharge generated gas (not limited to CO, which is the generated gas, but also including unreacted raw material gas and unreacted _CO2 ). While the figure shows one gas supply hole and one gas recovery hole, the number, location, and size of the holes are not limited and may be set as appropriate. Additionally, if the current collector plate 104 is breathable, the gas supply hole and the gas recovery hole are not necessarily required.

Note that if the cathode 101 has the role of transferring electrons, the current collector plate 104 is not necessarily required.

<Support plate 105>
The support plate 105 serves to support the anode. Therefore, the required rigidity of the support plate 105 varies depending on the thickness and rigidity of the anode. The support plate 105 must also have electrical conductivity so as to receive electrons from the anode. Examples of materials for the support plate 105 include Ti, SUS, and Ni. The support plate may also be a current collector plate with a flow path, such as 104.

As shown in Figure 1, the support plate 105 is provided with a gas flow path 105-1 for supplying raw material gas to the anode 102. This gas flow path enables raw material gas to be supplied uniformly and efficiently to the anode 102. Although nine gas flow paths are shown in the figure, the number, location, and size of these paths are not limited and can be set as appropriate.

In this embodiment, the anode 102 and support plate 105 are described as separate entities, but the anode 102 and support plate 105 may also be integrally formed (i.e., they may be configured as an integrated anode with a support function).

<Electrolytic cell 108>
The electrolytic cell 108 stores the product of electrolysis at the anode and serves as a source of raw material gas to be sent to the anode 102. Here, the raw material gas is water, hydrogen, or oxygen. Examples of materials for the electrolytic cell 108 include titanium, stainless steel, fluororesin, and polypropylene resin.

<Processing body>
The treated body is electrolyzed at the anode 102 to provide a source of raw material gas. The treated body contains benzene or an olefin, with ethylene or propylene being preferred as the olefin. When benzene or an olefin is used, it is possible to reduce the applied voltage required for electrolysis compared to when water is used. Furthermore, when benzene is used, phenol and carbon monoxide, which are raw materials for polycarbonate, can be efficiently produced simultaneously. Furthermore, when an olefin is used, olefin oxide and carbon monoxide, which are raw materials for polyurethane, can be efficiently produced simultaneously.

The treatment body can be an ionic liquid in which benzene or an olefin is dissolved. In the present disclosure, an ionic liquid refers to a molten salt (ionic compound) that is liquid at 25°C and is a salt composed of a cation component and an anion component. When an ionic liquid in which benzene or an olefin is dissolved is used as the treatment body, it is possible to further reduce the applied voltage required for electrolysis.
The ionic liquid is not particularly limited as long as it can dissolve benzene or an olefin and is not reactive with benzene or an olefin. An ionic liquid that is difficult to oxidize is preferably used. Here, the term "an ionic liquid that is difficult to oxidize" refers to an ionic liquid whose oxidation potential is more noble than 1.23 V vs. NHE.

Examples of cationic components contained in ionic liquids include alkylammonium, alkylphosphonium, alkylpyridinium, and alkylimidazolium. Examples of anionic components include tetrafluoroboric acid, hexafluorophosphate, trifluoromethanesulfonic acid, perfluoroalkylsulfonylimides, perfluoroalkylsulfonylmethides, cyclic perfluoroalkylsulfonylimides, hydrofluorides, bistrifluoromethanesulfonylimide anions, and bisfluoromethanesulfonylimide anions. Among these, ionic liquids that combine an alkylimidazolium as the cationic component and hexafluorophosphate as the anionic component are preferred, and alkylimidazolium hexafluorophosphates such as 2,3-dimethylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-octyl-3-methylimidazolium hexafluorophosphate are more preferred.

<Voltage application unit 106>
1 , the voltage application unit 106 applies a voltage between the cathode 101 and the anode 102 by applying a voltage to the current collector 104 and the support plate 105. As described above, the current collector 104 is a conductor and therefore supplies electrons to the cathode 101, while the support plate 105 is also a conductor and therefore receives electrons from the anode 102. Note that in cases where the current collector 104 is not required as described above, a voltage is applied between the cathode 101 and the support plate 105. A control unit (not shown) may be electrically connected to the voltage application unit 106 in order to apply an appropriate voltage.

<Reaction gas supply unit>
The solid electrolyte electrolysis device 100 of the present disclosure may be provided with a reactant gas supply unit (not shown) outside the solid electrolyte electrolysis device 100. That is, as long as _CO2 as the reactant gas is supplied to the surface 101-2, the reactant gas may be supplied from the reactant gas supply unit to the gas supply hole 104-1 via a pipe (not shown) or the like, or the reactant gas may be sprayed onto the surface 104-A of the current collector plate 104 opposite to the contact surface 104-B with the cathode 101. From an environmental perspective, it is preferable to use factory exhaust gas emitted from a factory as this reactant gas.

<Others>
The solid electrolyte electrolysis device 100 of the present disclosure may include other components necessary for a solid electrolyte electrolysis device, such as electrical components, control components, valves, pipes, tanks, pumps, and other piping components.

≪Applications≫
For the solid electrolyte electrolysis device according to the present disclosure as described above, it is possible to generate a synthesis gas containing at least CO and _H in a desired production ratio by using, for example, _CO gas emitted from a factory as a raw material and utilizing renewable energy such as a solar cell for the voltage application unit 106. Furthermore, when benzene is used as the treatment body, it is possible to generate phenol as a raw material for polycarbonate, and when olefin is used as the treatment body, it is possible to generate olefin oxide as a raw material for polyurethane, thereby making it possible to reuse _CO .

<Method for producing polycarbonate>
A method for producing polycarbonate using the solid electrolyte electrolysis device of the present disclosure will be described with reference to FIG. 3, assuming that the treated body in the present disclosure is benzene.
The polycarbonate production method of the present disclosure is characterized by including a bisphenol A production step (PC2-1) in which phenol and carbon monoxide produced using the solid electrolyte electrolysis device of the present disclosure are reacted with acetone to produce bisphenol A, a phosgene production step (PC2-2) in which carbon monoxide is reacted with chlorine to produce phosgene, and a polycarbonate production step (PC2-3) in which bisphenol A and phosgene are reacted to produce polycarbonate. Here, the production methods for each compound in the bisphenol A production step (PC2-1), the phosgene production step (PC2-2), and the polycarbonate production step (PC2-3) can be known production methods and are not particularly limited. The polycarbonate production method of the present disclosure allows phenol and carbon monoxide to be simultaneously produced by organic electrolysis using _CO2 and benzene, making it possible to reuse _CO2 and improve the efficiency (simplification) of equipment, thereby reducing production costs and capital investment costs. FIG. 4 shows an example of equipment and a flow diagram when the polycarbonate production method of the present disclosure is used.

Furthermore, chlorine, which is a raw material in the phosgene production step (PC2-2), can be obtained by electrolysis using a second solid electrolyte electrolysis device that uses brine instead of the treated body of the solid electrolyte electrolysis device according to the present disclosure. This allows for further reuse of _CO2 , while also enabling improved equipment efficiency (simplification), and further reducing capital investment costs. Here, chlorine is produced by electrolysis of brine at the anode of the second solid electrolyte electrolysis device. The second solid electrolyte electrolysis device includes a second cathode that performs a reduction reaction, a second anode that forms a pair of electrodes with the second cathode, a second electrolytic cell that holds brine, which is the treated body of electrolysis at the second anode, a second solid electrolyte that is interposed in contact between the second cathode and the second anode, and a second voltage application unit that applies a voltage between the second cathode and the second anode. The second solid electrolyte electrolysis device can be similar to the solid electrolyte electrolysis device according to the present disclosure, except that the treated body is brine.

<Method of producing polyurethane>
Using an olefin as the treated body according to the present disclosure, a method for producing polyurethane using a solid electrolyte electrolysis device according to the present disclosure will be described with reference to FIG. 5 .
The method for producing polyurethane according to the present disclosure is characterized by including an olefin glycol production step (PU2-1) in which olefin oxide and carbon monoxide produced using the solid electrolyte electrolysis device according to the present disclosure are reacted with water to produce olefin glycol, a phosgene production step (PU2-2) in which carbon monoxide is reacted with chlorine to produce phosgene, an isocyanate production step (PU2-3) in which phosgene is reacted with a primary amine to produce an isocyanate compound, and a polyurethane production step (PC2-4) in which the olefin glycol is reacted with the isocyanate compound to produce polyurethane carbonate. Here, the methods for producing each compound in the olefin glycol production step (PU2-1), phosgene production step (PU2-2), isocyanate production step (PU2-3), and polyurethane production step (PC2-4) can be known production methods and are not particularly limited. The polyurethane production method of the present disclosure allows for simultaneous production of olefin oxide and carbon monoxide by organic electrolysis from _CO2 and olefin, making it possible to reuse _CO2 and streamline (simplify) the equipment, thereby reducing production costs and capital investment costs. Figure 6 shows an example of equipment and a flow diagram for when the polyurethane production method of the present disclosure is used.

Furthermore, chlorine, which is a raw material in the phosgene production step (PU2-2), can be obtained by electrolysis using a second solid electrolyte electrolysis device that uses brine instead of the treatment body of the solid electrolyte electrolysis device according to the present disclosure. This allows for further reuse of _CO2 , while also enabling improved equipment efficiency (simplification), and further reducing capital investment costs. Here, chlorine is produced by electrolysis of brine at the anode of the second solid electrolyte electrolysis device. The second solid electrolyte electrolysis device includes a second cathode that performs a reduction reaction, a second anode that forms a pair of electrodes with the second cathode, a second electrolytic cell that holds brine, which is the treatment body of electrolysis at the second anode, a second solid electrolyte that is interposed in contact between the second cathode and the second anode, and a second voltage application unit that applies a voltage between the second cathode and the second anode. The second solid electrolyte electrolysis device may be similar to the solid electrolyte electrolysis device according to the present disclosure, except that the body to be treated is salt water.

The following provides a detailed explanation of the above-described embodiment using examples and comparative examples.

A solid electrolyte electrolysis device was assembled using the following components. The cathode was a mixture of conductive carbon black and silver nanocatalyst attached to carbon paper. The anode was a titanium mesh carrying iridium oxide. A cation exchange membrane was used as the solid electrolyte, and benzene (Example 1), ethylene (Example 2), propylene (Example 3), and ion-exchanged water (Comparative Example 1) were used as the treated bodies in each example and comparative example.

The solid electrolyte electrolysis device was operated, and 3.5 V was applied across the cathode and anode. The _CO2 reduction reaction was continued for 1 hour, and then the applied voltage to the anode was measured. The results are shown in Table 1.
Furthermore, when benzene was used, the solution in the electrolytic cell after electrolysis at the anode was analyzed with a GC-MS analyzer, and it was confirmed that phenol was produced. Similarly, when ethylene and propylene were used, ethylene oxide and propionate oxide were confirmed, respectively. Furthermore, in all Examples and Comparative Examples, when the gas discharged from the cathode was analyzed with a GC-MS analyzer, it was confirmed that carbon monoxide was produced.

The treated body was 1-octyl-3-methylimidazolium hexafluorophosphate, in which benzene was dissolved to a benzene concentration of 4% by volume, and electrolysis was performed in the same manner as in each example (Example 4). Figure 7 shows an enlarged portion of the cyclic voltammogram for Example 4, with peak A indicating an oxidation reaction occurring at the anode of the solid electrolyte electrolysis device and peak B indicating a reduction reaction occurring at the cathode of the solid electrolyte electrolysis device. Figure 8 also shows the results of FID-GC analysis of the treated body, a standard aqueous phenol solution, and ion-exchanged water before and after the oxidation reaction (electrolysis) at the anode. After the oxidation reaction, a peak appeared in the treated body at the same position as the peak of the standard aqueous phenol solution, confirming that phenol was produced by the oxidation reaction of the treated body.

100 Solid electrolyte electrolysis device 101 Cathode
101-1: Cathode surface in contact with the solid electrolyte; 101-2: Cathode surface in contact with the current collector; 102: Anode
102-1 Anode surface in contact with support plate 102-2 Anode surface in contact with solid electrolyte 103 Solid electrolyte 104 Current collector plate 104-1 Gas supply hole in current collector plate 104-2 Gas recovery hole in current collector plate 105 Support plate 105-1 Gas flow path in support plate 106 Voltage application unit 107 Solid base 108 Electrolytic cell

Claims (6)

a cathode where a reduction reaction takes place;
a supply means for supplying gaseous carbon dioxide toward the cathode;
an anode that forms a pair of electrodes with the cathode;
an electrolytic cell for holding a treatment body to be electrolyzed by the anode;
a solid electrolyte interposed between the cathode and the anode in contact therewith;
a voltage application unit that applies a voltage between the cathode and the anode,
The solid electrolyte electrolysis device , wherein the treatment body contains benzene or an olefin . The solid electrolyte electrolysis device according to claim 1, characterized in that the olefin includes ethylene or propylene. A method for producing polycarbonate using the solid electrolyte electrolysis device according to claim 1,
the treated body contains benzene,
a bisphenol A production step of electrolyzing the benzene at the anode to produce at least phenol, producing at least carbon monoxide from carbon dioxide at the cathode, and reacting the phenol with acetone to produce bisphenol A;
a phosgene production step in which the carbon monoxide is reacted with chlorine to produce phosgene;
a polycarbonate production step of reacting the bisphenol A with the phosgene to produce a polycarbonate. the chlorine is generated by electrolysis of brine in a second solid electrolyte electrolysis device;
The second solid electrolyte electrolysis device comprises:
a second cathode where a reduction reaction occurs;
a second anode forming a pair of electrodes together with the second cathode;
an electrolytic cell for holding brine, which is the treatment body of electrolysis at the second anode;
a solid electrolyte interposed between and in contact with the second cathode and the second anode;
4. The method for producing polycarbonate according to claim 3, further comprising: a voltage application unit that applies a voltage between the second cathode and the second anode. A method for producing polyurethane using the solid electrolyte electrolysis device according to claim 1,
the treated body comprises an olefin,
an olefin glycol production step of electrolyzing the olefin at the anode to produce at least an olefin oxide, producing at least carbon monoxide from carbon dioxide at the cathode, and reacting the olefin oxide with water to produce olefin glycol;
a phosgene production step in which the carbon monoxide is reacted with chlorine to produce phosgene;
an isocyanate-producing step of reacting the phosgene with a primary amine to produce an isocyanate compound;
a polyurethane production step of reacting the olefin glycol with the isocyanate compound to produce polyurethane. the chlorine is generated by electrolysis of brine in a second solid electrolyte electrolysis device;
The second solid electrolyte electrolysis device comprises:
a second cathode where a reduction reaction occurs;
a second anode forming a pair of electrodes together with the second cathode;
an electrolytic cell for holding brine, which is the treatment body of electrolysis at the second anode;
a second solid electrolyte interposed between and in contact with the second cathode and the second anode;
6. The method for producing polyurethane according to claim 5, further comprising: a second voltage application unit that applies a voltage between the second cathode and the second anode.